Changeset 1854


Ignore:
Timestamp:
03/09/12 05:54:40 (10 years ago)
Author:
fielding@…
Message:

(editorial) move content negotiation within section on representation

Location:
draft-ietf-httpbis/latest
Files:
2 edited

Legend:

Unmodified
Added
Removed

  • draft-ietf-httpbis/latest/p2-semantics.html

    r1853 r1854  
    480480      <link rel="Chapter" title="8 Protocol Parameters" href="#rfc.section.8">
    481481      <link rel="Chapter" title="9 Payload" href="#rfc.section.9">
    482       <link rel="Chapter" title="10 Content Negotiation" href="#rfc.section.10">
    483       <link rel="Chapter" title="11 Header Field Definitions" href="#rfc.section.11">
    484       <link rel="Chapter" title="12 IANA Considerations" href="#rfc.section.12">
    485       <link rel="Chapter" title="13 Security Considerations" href="#rfc.section.13">
    486       <link rel="Chapter" title="14 Acknowledgments" href="#rfc.section.14">
    487       <link rel="Chapter" href="#rfc.section.15" title="15 References">
     482      <link rel="Chapter" title="10 Header Field Definitions" href="#rfc.section.10">
     483      <link rel="Chapter" title="11 IANA Considerations" href="#rfc.section.11">
     484      <link rel="Chapter" title="12 Security Considerations" href="#rfc.section.12">
     485      <link rel="Chapter" title="13 Acknowledgments" href="#rfc.section.13">
     486      <link rel="Chapter" href="#rfc.section.14" title="14 References">
    488487      <link rel="Appendix" title="A Differences between HTTP and MIME" href="#rfc.section.A">
    489488      <link rel="Appendix" title="B Additional Features" href="#rfc.section.B">
    … …  
    591590               <li><a href="#rfc.section.3.2">3.2</a>&nbsp;&nbsp;&nbsp;<a href="#representation.header.fields">Representation Header Fields</a></li>
    592591               <li><a href="#rfc.section.3.3">3.3</a>&nbsp;&nbsp;&nbsp;<a href="#representation.data">Representation Data</a></li>
     592               <li><a href="#rfc.section.3.4">3.4</a>&nbsp;&nbsp;&nbsp;<a href="#content.negotiation">Content Negotiation</a><ul>
     593                     <li><a href="#rfc.section.3.4.1">3.4.1</a>&nbsp;&nbsp;&nbsp;<a href="#server-driven.negotiation">Server-driven Negotiation</a></li>
     594                     <li><a href="#rfc.section.3.4.2">3.4.2</a>&nbsp;&nbsp;&nbsp;<a href="#agent-driven.negotiation">Agent-driven Negotiation</a></li>
     595                     <li><a href="#rfc.section.3.4.3">3.4.3</a>&nbsp;&nbsp;&nbsp;<a href="#quality.values">Quality Values</a></li>
     596                  </ul>
     597               </li>
    593598            </ul>
    594599         </li>
    … …  
    696701            </ul>
    697702         </li>
    698          <li><a href="#rfc.section.10">10.</a>&nbsp;&nbsp;&nbsp;<a href="#content.negotiation">Content Negotiation</a><ul>
    699                <li><a href="#rfc.section.10.1">10.1</a>&nbsp;&nbsp;&nbsp;<a href="#server-driven.negotiation">Server-driven Negotiation</a></li>
    700                <li><a href="#rfc.section.10.2">10.2</a>&nbsp;&nbsp;&nbsp;<a href="#agent-driven.negotiation">Agent-driven Negotiation</a></li>
    701                <li><a href="#rfc.section.10.3">10.3</a>&nbsp;&nbsp;&nbsp;<a href="#quality.values">Quality Values</a></li>
     703         <li><a href="#rfc.section.10">10.</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.definitions">Header Field Definitions</a><ul>
     704               <li><a href="#rfc.section.10.1">10.1</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept">Accept</a></li>
     705               <li><a href="#rfc.section.10.2">10.2</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept-charset">Accept-Charset</a></li>
     706               <li><a href="#rfc.section.10.3">10.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept-encoding">Accept-Encoding</a></li>
     707               <li><a href="#rfc.section.10.4">10.4</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept-language">Accept-Language</a></li>
     708               <li><a href="#rfc.section.10.5">10.5</a>&nbsp;&nbsp;&nbsp;<a href="#header.allow">Allow</a></li>
     709               <li><a href="#rfc.section.10.6">10.6</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-encoding">Content-Encoding</a></li>
     710               <li><a href="#rfc.section.10.7">10.7</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-language">Content-Language</a></li>
     711               <li><a href="#rfc.section.10.8">10.8</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-location">Content-Location</a></li>
     712               <li><a href="#rfc.section.10.9">10.9</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-type">Content-Type</a></li>
     713               <li><a href="#rfc.section.10.10">10.10</a>&nbsp;&nbsp;&nbsp;<a href="#header.date">Date</a></li>
     714               <li><a href="#rfc.section.10.11">10.11</a>&nbsp;&nbsp;&nbsp;<a href="#header.expect">Expect</a></li>
     715               <li><a href="#rfc.section.10.12">10.12</a>&nbsp;&nbsp;&nbsp;<a href="#header.from">From</a></li>
     716               <li><a href="#rfc.section.10.13">10.13</a>&nbsp;&nbsp;&nbsp;<a href="#header.location">Location</a></li>
     717               <li><a href="#rfc.section.10.14">10.14</a>&nbsp;&nbsp;&nbsp;<a href="#header.max-forwards">Max-Forwards</a></li>
     718               <li><a href="#rfc.section.10.15">10.15</a>&nbsp;&nbsp;&nbsp;<a href="#header.referer">Referer</a></li>
     719               <li><a href="#rfc.section.10.16">10.16</a>&nbsp;&nbsp;&nbsp;<a href="#header.retry-after">Retry-After</a></li>
     720               <li><a href="#rfc.section.10.17">10.17</a>&nbsp;&nbsp;&nbsp;<a href="#header.server">Server</a></li>
     721               <li><a href="#rfc.section.10.18">10.18</a>&nbsp;&nbsp;&nbsp;<a href="#header.user-agent">User-Agent</a></li>
    702722            </ul>
    703723         </li>
    704          <li><a href="#rfc.section.11">11.</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.definitions">Header Field Definitions</a><ul>
    705                <li><a href="#rfc.section.11.1">11.1</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept">Accept</a></li>
    706                <li><a href="#rfc.section.11.2">11.2</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept-charset">Accept-Charset</a></li>
    707                <li><a href="#rfc.section.11.3">11.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept-encoding">Accept-Encoding</a></li>
    708                <li><a href="#rfc.section.11.4">11.4</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept-language">Accept-Language</a></li>
    709                <li><a href="#rfc.section.11.5">11.5</a>&nbsp;&nbsp;&nbsp;<a href="#header.allow">Allow</a></li>
    710                <li><a href="#rfc.section.11.6">11.6</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-encoding">Content-Encoding</a></li>
    711                <li><a href="#rfc.section.11.7">11.7</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-language">Content-Language</a></li>
    712                <li><a href="#rfc.section.11.8">11.8</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-location">Content-Location</a></li>
    713                <li><a href="#rfc.section.11.9">11.9</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-type">Content-Type</a></li>
    714                <li><a href="#rfc.section.11.10">11.10</a>&nbsp;&nbsp;&nbsp;<a href="#header.date">Date</a></li>
    715                <li><a href="#rfc.section.11.11">11.11</a>&nbsp;&nbsp;&nbsp;<a href="#header.expect">Expect</a></li>
    716                <li><a href="#rfc.section.11.12">11.12</a>&nbsp;&nbsp;&nbsp;<a href="#header.from">From</a></li>
    717                <li><a href="#rfc.section.11.13">11.13</a>&nbsp;&nbsp;&nbsp;<a href="#header.location">Location</a></li>
    718                <li><a href="#rfc.section.11.14">11.14</a>&nbsp;&nbsp;&nbsp;<a href="#header.max-forwards">Max-Forwards</a></li>
    719                <li><a href="#rfc.section.11.15">11.15</a>&nbsp;&nbsp;&nbsp;<a href="#header.referer">Referer</a></li>
    720                <li><a href="#rfc.section.11.16">11.16</a>&nbsp;&nbsp;&nbsp;<a href="#header.retry-after">Retry-After</a></li>
    721                <li><a href="#rfc.section.11.17">11.17</a>&nbsp;&nbsp;&nbsp;<a href="#header.server">Server</a></li>
    722                <li><a href="#rfc.section.11.18">11.18</a>&nbsp;&nbsp;&nbsp;<a href="#header.user-agent">User-Agent</a></li>
    723             </ul>
    724          </li>
    725          <li><a href="#rfc.section.12">12.</a>&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
    726                <li><a href="#rfc.section.12.1">12.1</a>&nbsp;&nbsp;&nbsp;<a href="#method.registry">Method Registry</a><ul>
    727                      <li><a href="#rfc.section.12.1.1">12.1.1</a>&nbsp;&nbsp;&nbsp;<a href="#method.procedure">Procedure</a></li>
    728                      <li><a href="#rfc.section.12.1.2">12.1.2</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.methods">Considerations for New Methods</a></li>
    729                      <li><a href="#rfc.section.12.1.3">12.1.3</a>&nbsp;&nbsp;&nbsp;<a href="#method.registration">Registrations</a></li>
     724         <li><a href="#rfc.section.11">11.</a>&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
     725               <li><a href="#rfc.section.11.1">11.1</a>&nbsp;&nbsp;&nbsp;<a href="#method.registry">Method Registry</a><ul>
     726                     <li><a href="#rfc.section.11.1.1">11.1.1</a>&nbsp;&nbsp;&nbsp;<a href="#method.procedure">Procedure</a></li>
     727                     <li><a href="#rfc.section.11.1.2">11.1.2</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.methods">Considerations for New Methods</a></li>
     728                     <li><a href="#rfc.section.11.1.3">11.1.3</a>&nbsp;&nbsp;&nbsp;<a href="#method.registration">Registrations</a></li>
    730729                  </ul>
    731730               </li>
    732                <li><a href="#rfc.section.12.2">12.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.registry">Status Code Registry</a><ul>
    733                      <li><a href="#rfc.section.12.2.1">12.2.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.procedure">Procedure</a></li>
    734                      <li><a href="#rfc.section.12.2.2">12.2.2</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></li>
    735                      <li><a href="#rfc.section.12.2.3">12.2.3</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.registration">Registrations</a></li>
     731               <li><a href="#rfc.section.11.2">11.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.registry">Status Code Registry</a><ul>
     732                     <li><a href="#rfc.section.11.2.1">11.2.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.procedure">Procedure</a></li>
     733                     <li><a href="#rfc.section.11.2.2">11.2.2</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></li>
     734                     <li><a href="#rfc.section.11.2.3">11.2.3</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.registration">Registrations</a></li>
    736735                  </ul>
    737736               </li>
    738                <li><a href="#rfc.section.12.3">12.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.registry">Header Field Registry</a><ul>
    739                      <li><a href="#rfc.section.12.3.1">12.3.1</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.header.fields">Considerations for New Header Fields</a></li>
    740                      <li><a href="#rfc.section.12.3.2">12.3.2</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Registrations</a></li>
     737               <li><a href="#rfc.section.11.3">11.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.registry">Header Field Registry</a><ul>
     738                     <li><a href="#rfc.section.11.3.1">11.3.1</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.header.fields">Considerations for New Header Fields</a></li>
     739                     <li><a href="#rfc.section.11.3.2">11.3.2</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Registrations</a></li>
    741740                  </ul>
    742741               </li>
    743                <li><a href="#rfc.section.12.4">12.4</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.registry">Content Coding Registry</a><ul>
    744                      <li><a href="#rfc.section.12.4.1">12.4.1</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.procedure">Procedure</a></li>
    745                      <li><a href="#rfc.section.12.4.2">12.4.2</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.registration">Registrations</a></li>
     742               <li><a href="#rfc.section.11.4">11.4</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.registry">Content Coding Registry</a><ul>
     743                     <li><a href="#rfc.section.11.4.1">11.4.1</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.procedure">Procedure</a></li>
     744                     <li><a href="#rfc.section.11.4.2">11.4.2</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.registration">Registrations</a></li>
    746745                  </ul>
    747746               </li>
    748747            </ul>
    749748         </li>
    750          <li><a href="#rfc.section.13">13.</a>&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul>
    751                <li><a href="#rfc.section.13.1">13.1</a>&nbsp;&nbsp;&nbsp;<a href="#security.sensitive">Transfer of Sensitive Information</a></li>
    752                <li><a href="#rfc.section.13.2">13.2</a>&nbsp;&nbsp;&nbsp;<a href="#encoding.sensitive.information.in.uris">Encoding Sensitive Information in URIs</a></li>
    753                <li><a href="#rfc.section.13.3">13.3</a>&nbsp;&nbsp;&nbsp;<a href="#location.spoofing-leakage">Location Header Fields: Spoofing and Information Leakage</a></li>
    754                <li><a href="#rfc.section.13.4">13.4</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.13.4">Security Considerations for CONNECT</a></li>
    755                <li><a href="#rfc.section.13.5">13.5</a>&nbsp;&nbsp;&nbsp;<a href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></li>
     749         <li><a href="#rfc.section.12">12.</a>&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul>
     750               <li><a href="#rfc.section.12.1">12.1</a>&nbsp;&nbsp;&nbsp;<a href="#security.sensitive">Transfer of Sensitive Information</a></li>
     751               <li><a href="#rfc.section.12.2">12.2</a>&nbsp;&nbsp;&nbsp;<a href="#encoding.sensitive.information.in.uris">Encoding Sensitive Information in URIs</a></li>
     752               <li><a href="#rfc.section.12.3">12.3</a>&nbsp;&nbsp;&nbsp;<a href="#location.spoofing-leakage">Location Header Fields: Spoofing and Information Leakage</a></li>
     753               <li><a href="#rfc.section.12.4">12.4</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.12.4">Security Considerations for CONNECT</a></li>
     754               <li><a href="#rfc.section.12.5">12.5</a>&nbsp;&nbsp;&nbsp;<a href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></li>
    756755            </ul>
    757756         </li>
    758          <li><a href="#rfc.section.14">14.</a>&nbsp;&nbsp;&nbsp;<a href="#acks">Acknowledgments</a></li>
    759          <li><a href="#rfc.section.15">15.</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
    760                <li><a href="#rfc.section.15.1">15.1</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
    761                <li><a href="#rfc.section.15.2">15.2</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
     757         <li><a href="#rfc.section.13">13.</a>&nbsp;&nbsp;&nbsp;<a href="#acks">Acknowledgments</a></li>
     758         <li><a href="#rfc.section.14">14.</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
     759               <li><a href="#rfc.section.14.1">14.1</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
     760               <li><a href="#rfc.section.14.2">14.2</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
    762761            </ul>
    763762         </li>
    … …  
    913912               <tr>
    914913                  <td class="left">Content-Encoding</td>
    915                   <td class="left"><a href="#header.content-encoding" id="rfc.xref.header.content-encoding.1" title="Content-Encoding">Section&nbsp;11.6</a></td>
     914                  <td class="left"><a href="#header.content-encoding" id="rfc.xref.header.content-encoding.1" title="Content-Encoding">Section&nbsp;10.6</a></td>
    916915               </tr>
    917916               <tr>
    918917                  <td class="left">Content-Language</td>
    919                   <td class="left"><a href="#header.content-language" id="rfc.xref.header.content-language.1" title="Content-Language">Section&nbsp;11.7</a></td>
     918                  <td class="left"><a href="#header.content-language" id="rfc.xref.header.content-language.1" title="Content-Language">Section&nbsp;10.7</a></td>
    920919               </tr>
    921920               <tr>
    922921                  <td class="left">Content-Location</td>
    923                   <td class="left"><a href="#header.content-location" id="rfc.xref.header.content-location.1" title="Content-Location">Section&nbsp;11.8</a></td>
     922                  <td class="left"><a href="#header.content-location" id="rfc.xref.header.content-location.1" title="Content-Location">Section&nbsp;10.8</a></td>
    924923               </tr>
    925924               <tr>
    926925                  <td class="left">Content-Type</td>
    927                   <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.1" title="Content-Type">Section&nbsp;11.9</a></td>
     926                  <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.1" title="Content-Type">Section&nbsp;10.9</a></td>
    928927               </tr>
    929928               <tr>
    … …  
    985984         defined by the <a href="#header.content-type" class="smpl">Content-Type</a> header field.
    986985      </p>
     986      <h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a>&nbsp;<a id="content.negotiation" href="#content.negotiation">Content Negotiation</a></h2>
     987      <p id="rfc.section.3.4.p.1">HTTP responses include a representation which contains information for interpretation, whether by a human user or for further
     988         processing. Often, the server has different ways of representing the same information; for example, in different formats,
     989         languages, or using different character encodings.
     990      </p>
     991      <p id="rfc.section.3.4.p.2">HTTP clients and their users might have different or variable capabilities, characteristics or preferences which would influence
     992         which representation, among those available from the server, would be best for the server to deliver. For this reason, HTTP
     993         provides mechanisms for "content negotiation" — a process of allowing selection of a representation of a given resource, when
     994         more than one is available.
     995      </p>
     996      <p id="rfc.section.3.4.p.3">This specification defines two patterns of content negotiation; "server-driven", where the server selects the representation
     997         based upon the client's stated preferences, and "agent-driven" negotiation, where the server provides a list of representations
     998         for the client to choose from, based upon their metadata. In addition, there are other patterns: some applications use an
     999         "active content" pattern, where the server returns active content which runs on the client and, based on client available
     1000         parameters, selects additional resources to invoke. "Transparent Content Negotiation" (<a href="#RFC2295" id="rfc.xref.RFC2295.1"><cite title="Transparent Content Negotiation in HTTP">[RFC2295]</cite></a>) has also been proposed.
     1001      </p>
     1002      <p id="rfc.section.3.4.p.4">These patterns are all widely used, and have trade-offs in applicability and practicality. In particular, when the number
     1003         of preferences or capabilities to be expressed by a client are large (such as when many different formats are supported by
     1004         a user-agent), server-driven negotiation becomes unwieldy, and might not be appropriate. Conversely, when the number of representations
     1005         to choose from is very large, agent-driven negotiation might not be appropriate.
     1006      </p>
     1007      <p id="rfc.section.3.4.p.5">Note that, in all cases, the supplier of representations has the responsibility for determining which representations might
     1008         be considered to be the "same information".
     1009      </p>
     1010      <h3 id="rfc.section.3.4.1"><a href="#rfc.section.3.4.1">3.4.1</a>&nbsp;<a id="server-driven.negotiation" href="#server-driven.negotiation">Server-driven Negotiation</a></h3>
     1011      <p id="rfc.section.3.4.1.p.1">If the selection of the best representation for a response is made by an algorithm located at the server, it is called server-driven
     1012         negotiation. Selection is based on the available representations of the response (the dimensions over which it can vary; e.g.,
     1013         language, content-coding, etc.) and the contents of particular header fields in the request message or on other information
     1014         pertaining to the request (such as the network address of the client).
     1015      </p>
     1016      <p id="rfc.section.3.4.1.p.2">Server-driven negotiation is advantageous when the algorithm for selecting from among the available representations is difficult
     1017         to describe to the user agent, or when the server desires to send its "best guess" to the client along with the first response
     1018         (hoping to avoid the round-trip delay of a subsequent request if the "best guess" is good enough for the user). In order to
     1019         improve the server's guess, the user agent <em class="bcp14">MAY</em> include request header fields (<a href="#header.accept" class="smpl">Accept</a>, <a href="#header.accept-language" class="smpl">Accept-Language</a>, <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a>, etc.) which describe its preferences for such a response.
     1020      </p>
     1021      <p id="rfc.section.3.4.1.p.3">Server-driven negotiation has disadvantages: </p>
     1022      <ol>
     1023         <li>It is impossible for the server to accurately determine what might be "best" for any given user, since that would require
     1024            complete knowledge of both the capabilities of the user agent and the intended use for the response (e.g., does the user want
     1025            to view it on screen or print it on paper?).
     1026         </li>
     1027         <li>Having the user agent describe its capabilities in every request can be both very inefficient (given that only a small percentage
     1028            of responses have multiple representations) and a potential violation of the user's privacy.
     1029         </li>
     1030         <li>It complicates the implementation of an origin server and the algorithms for generating responses to a request.</li>
     1031         <li>It might limit a public cache's ability to use the same response for multiple user's requests.</li>
     1032      </ol>
     1033      <p id="rfc.section.3.4.1.p.4">Server-driven negotiation allows the user agent to specify its preferences, but it cannot expect responses to always honor
     1034         them. For example, the origin server might not implement server-driven negotiation, or it might decide that sending a response
     1035         that doesn't conform to them is better than sending a <a href="#status.406" class="smpl">406
     1036            (Not Acceptable)</a> response.
     1037      </p>
     1038      <p id="rfc.section.3.4.1.p.5">HTTP/1.1 includes the following header fields for enabling server-driven negotiation through description of user agent capabilities
     1039         and user preferences: <a href="#header.accept" class="smpl">Accept</a> (<a href="#header.accept" id="rfc.xref.header.accept.1" title="Accept">Section&nbsp;10.1</a>), <a href="#header.accept-charset" class="smpl">Accept-Charset</a> (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.1" title="Accept-Charset">Section&nbsp;10.2</a>), <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.1" title="Accept-Encoding">Section&nbsp;10.3</a>), <a href="#header.accept-language" class="smpl">Accept-Language</a> (<a href="#header.accept-language" id="rfc.xref.header.accept-language.1" title="Accept-Language">Section&nbsp;10.4</a>), and <a href="#header.user-agent" class="smpl">User-Agent</a> (<a href="#header.user-agent" id="rfc.xref.header.user-agent.1" title="User-Agent">Section&nbsp;10.18</a>). However, an origin server is not limited to these dimensions and <em class="bcp14">MAY</em> vary the response based on any aspect of the request, including aspects of the connection (e.g., IP address) or information
     1040         within extension header fields not defined by this specification.
     1041      </p>
     1042      <div class="note" id="rfc.section.3.4.1.p.6">
     1043         <p> <b>Note:</b> In practice, <a href="#header.user-agent" class="smpl">User-Agent</a> based negotiation is fragile, because new clients might not be recognized.
     1044         </p>
     1045      </div>
     1046      <p id="rfc.section.3.4.1.p.7">The <a href="p6-cache.html#header.vary" class="smpl">Vary</a> header field (<a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) can be used to express the parameters the server uses to select a representation that is subject to server-driven negotiation.
     1047      </p>
     1048      <h3 id="rfc.section.3.4.2"><a href="#rfc.section.3.4.2">3.4.2</a>&nbsp;<a id="agent-driven.negotiation" href="#agent-driven.negotiation">Agent-driven Negotiation</a></h3>
     1049      <p id="rfc.section.3.4.2.p.1">With agent-driven negotiation, selection of the best representation for a response is performed by the user agent after receiving
     1050         an initial response from the origin server. Selection is based on a list of the available representations of the response
     1051         included within the header fields or body of the initial response, with each representation identified by its own URI. Selection
     1052         from among the representations can be performed automatically (if the user agent is capable of doing so) or manually by the
     1053         user selecting from a generated (possibly hypertext) menu.
     1054      </p>
     1055      <p id="rfc.section.3.4.2.p.2">Agent-driven negotiation is advantageous when the response would vary over commonly-used dimensions (such as type, language,
     1056         or encoding), when the origin server is unable to determine a user agent's capabilities from examining the request, and generally
     1057         when public caches are used to distribute server load and reduce network usage.
     1058      </p>
     1059      <p id="rfc.section.3.4.2.p.3">Agent-driven negotiation suffers from the disadvantage of needing a second request to obtain the best alternate representation.
     1060         This second request is only efficient when caching is used. In addition, this specification does not define any mechanism
     1061         for supporting automatic selection, though it also does not prevent any such mechanism from being developed as an extension
     1062         and used within HTTP/1.1.
     1063      </p>
     1064      <p id="rfc.section.3.4.2.p.4">This specification defines the <a href="#status.300" class="smpl">300 (Multiple Choices)</a> and <a href="#status.406" class="smpl">406 (Not Acceptable)</a> status codes for enabling agent-driven negotiation when the server is unwilling or unable to provide a varying response using
     1065         server-driven negotiation.
     1066      </p>
     1067      <h3 id="rfc.section.3.4.3"><a href="#rfc.section.3.4.3">3.4.3</a>&nbsp;<a id="quality.values" href="#quality.values">Quality Values</a></h3>
     1068      <p id="rfc.section.3.4.3.p.1">Many of the request header fields for server-driven content negotiation use a common parameter, named "q", to assign a relative
     1069         "weight" to the preference for that associated kind of content. This weight is referred to as a "quality value" (or "qvalue")
     1070         because the same parameter name is often used within server configurations to assign a weight to the relative quality of the
     1071         various representations that can be selected for a resource.
     1072      </p>
     1073      <p id="rfc.section.3.4.3.p.2">The weight is normalized to a real number in the range 0 through 1, where 0.001 is the least preferred and 1 is the most preferred;
     1074         a value of 0 means "not acceptable". If no "q" parameter is present, the default weight is 1.
     1075      </p>
     1076      <div id="rfc.figure.u.2"></div><pre class="inline"><span id="rfc.iref.g.1"></span><span id="rfc.iref.g.2"></span>  <a href="#quality.values" class="smpl">weight</a> = <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> "q=" <a href="#quality.values" class="smpl">qvalue</a>
     1077  <a href="#quality.values" class="smpl">qvalue</a> = ( "0" [ "." 0*3<a href="#imported.abnf" class="smpl">DIGIT</a> ] )
     1078         / ( "1" [ "." 0*3("0") ] )
     1079</pre><p id="rfc.section.3.4.3.p.4">A sender of qvalue <em class="bcp14">MUST NOT</em> generate more than three digits after the decimal point. User configuration of these values ought to be limited in the same
     1080         fashion.
     1081      </p>
    9871082      <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a id="methods" href="#methods">Request Methods</a></h1>
    9881083      <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a id="method.overview" href="#method.overview">Overview</a></h2>
    … …  
    9901085         this request and what is expected by the client as a successful result. The request semantics <em class="bcp14">MAY</em> be further specialized by the semantics of some header fields when present in a request (<a href="#request.header.fields" title="Request Header Fields">Section&nbsp;5</a>) if those additional semantics do not conflict with the method.
    9911086      </p>
    992       <div id="rfc.figure.u.2"></div><pre class="inline"><span id="rfc.iref.g.1"></span>  <a href="#method.overview" class="smpl">method</a> = <a href="#imported.abnf" class="smpl">token</a>
     1087      <div id="rfc.figure.u.3"></div><pre class="inline"><span id="rfc.iref.g.3"></span>  <a href="#method.overview" class="smpl">method</a> = <a href="#imported.abnf" class="smpl">token</a>
    9931088</pre><p id="rfc.section.4.1.p.3">HTTP was originally designed to be usable as an interface to distributed object systems. The request method was envisioned
    9941089         as applying semantics to a target resource in much the same way as invoking a defined method on an identified object would
    … …  
    10601155      </p>
    10611156      <p id="rfc.section.4.1.p.7">Additional methods <em class="bcp14">MAY</em> be used in HTTP; many have already been standardized outside the scope of this specification and registered within the HTTP
    1062          Method Registry maintained by IANA, as defined in <a href="#method.registry" title="Method Registry">Section&nbsp;12.1</a>.
    1063       </p>
    1064       <p id="rfc.section.4.1.p.8">The set of methods allowed by a target resource can be listed in an <a href="#header.allow" class="smpl">Allow</a> header field (<a href="#header.allow" id="rfc.xref.header.allow.1" title="Allow">Section&nbsp;11.5</a>). However, the set of allowed methods can change dynamically. When a request message is received that is unrecognized or
     1157         Method Registry maintained by IANA, as defined in <a href="#method.registry" title="Method Registry">Section&nbsp;11.1</a>.
     1158      </p>
     1159      <p id="rfc.section.4.1.p.8">The set of methods allowed by a target resource can be listed in an <a href="#header.allow" class="smpl">Allow</a> header field (<a href="#header.allow" id="rfc.xref.header.allow.1" title="Allow">Section&nbsp;10.5</a>). However, the set of allowed methods can change dynamically. When a request message is received that is unrecognized or
    10651160         not implemented by an origin server, the origin server <em class="bcp14">SHOULD</em> respond with the <a href="#status.501" class="smpl">501 (Not Implemented)</a> status code. When a request message is received that is known by an origin server but not allowed for the target resource,
    10661161         the origin server <em class="bcp14">SHOULD</em> respond with the <a href="#status.405" class="smpl">405 (Method Not Allowed)</a> status code.
    … …  
    11151210         are defined to be cacheable. In general, safe methods that do not depend on a current or authoritative response are cacheable,
    11161211         though the overwhelming majority of caches only support GET and HEAD. HTTP requirements for cache behavior and cacheable responses
    1117          are defined in <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>.
     1212         are defined in <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>.
    11181213      </p>
    11191214      <h2 id="rfc.section.4.3"><a href="#rfc.section.4.3">4.3</a>&nbsp;<a id="method.definitions" href="#method.definitions">Method Definitions</a></h2>
    11201215      <h3 id="rfc.section.4.3.1"><a href="#rfc.section.4.3.1">4.3.1</a>&nbsp;<a id="GET" href="#GET">GET</a></h3>
    1121       <div id="rfc.iref.g.2"></div>
     1216      <div id="rfc.iref.g.4"></div>
    11221217      <div id="rfc.iref.m.1"></div>
    11231218      <p id="rfc.section.4.3.1.p.1">The GET method requests transfer of a current representation of the target resource.</p>
    … …  
    11351230         to reject the request.
    11361231      </p>
    1137       <p id="rfc.section.4.3.1.p.6">The response to a GET request is cacheable and <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests (see <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    1138       </p>
    1139       <p id="rfc.section.4.3.1.p.7">See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;13.2</a> for security considerations when used for forms.
     1232      <p id="rfc.section.4.3.1.p.6">The response to a GET request is cacheable and <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests (see <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1233      </p>
     1234      <p id="rfc.section.4.3.1.p.7">See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;12.2</a> for security considerations when used for forms.
    11401235      </p>
    11411236      <h3 id="rfc.section.4.3.2"><a href="#rfc.section.4.3.2">4.3.2</a>&nbsp;<a id="HEAD" href="#HEAD">HEAD</a></h3>
    … …  
    11461241         hypertext links for validity, accessibility, and recent modification.
    11471242      </p>
    1148       <p id="rfc.section.4.3.2.p.2">The response to a HEAD request is cacheable and <em class="bcp14">MAY</em> be used to satisfy a subsequent HEAD request. It also has potential side effects on previously stored responses to GET; see <a href="p6-cache.html#head.effects" title="Updating Caches with HEAD Responses">Section 5</a> of <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>.
     1243      <p id="rfc.section.4.3.2.p.2">The response to a HEAD request is cacheable and <em class="bcp14">MAY</em> be used to satisfy a subsequent HEAD request. It also has potential side effects on previously stored responses to GET; see <a href="p6-cache.html#head.effects" title="Updating Caches with HEAD Responses">Section 5</a> of <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>.
    11491244      </p>
    11501245      <p id="rfc.section.4.3.2.p.3">Bodies on HEAD requests have no defined semantics. Note that sending a body on a HEAD request might cause some existing implementations
    … …  
    11691264         the result.
    11701265      </p>
    1171       <p id="rfc.section.4.3.3.p.4">If a resource has been created on the origin server, the response <em class="bcp14">SHOULD</em> be <a href="#status.201" class="smpl">201 (Created)</a> and contain a representation which describes the status of the request and refers to the new resource, and a <a href="#header.location" class="smpl">Location</a> header field (see <a href="#header.location" id="rfc.xref.header.location.1" title="Location">Section&nbsp;11.13</a>).
    1172       </p>
    1173       <p id="rfc.section.4.3.3.p.5">Responses to POST requests are only cacheable when they include explicit freshness information (see <a href="p6-cache.html#calculating.freshness.lifetime" title="Calculating Freshness Lifetime">Section 4.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). A cached POST response with a <a href="#header.content-location" class="smpl">Content-Location</a> header field (see <a href="#header.content-location" id="rfc.xref.header.content-location.2" title="Content-Location">Section&nbsp;11.8</a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests.
     1266      <p id="rfc.section.4.3.3.p.4">If a resource has been created on the origin server, the response <em class="bcp14">SHOULD</em> be <a href="#status.201" class="smpl">201 (Created)</a> and contain a representation which describes the status of the request and refers to the new resource, and a <a href="#header.location" class="smpl">Location</a> header field (see <a href="#header.location" id="rfc.xref.header.location.1" title="Location">Section&nbsp;10.13</a>).
     1267      </p>
     1268      <p id="rfc.section.4.3.3.p.5">Responses to POST requests are only cacheable when they include explicit freshness information (see <a href="p6-cache.html#calculating.freshness.lifetime" title="Calculating Freshness Lifetime">Section 4.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.6"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). A cached POST response with a <a href="#header.content-location" class="smpl">Content-Location</a> header field (see <a href="#header.content-location" id="rfc.xref.header.content-location.2" title="Content-Location">Section&nbsp;10.8</a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests.
    11741269      </p>
    11751270      <p id="rfc.section.4.3.3.p.6">Note that POST caching is not widely implemented. However, the <a href="#status.303" class="smpl">303 (See Other)</a> response can be used to direct the user agent to retrieve a cacheable representation of the resource.
    … …  
    12371332      </p>
    12381333      <p id="rfc.section.4.3.4.p.11">Responses to the PUT method are not cacheable. If a PUT request passes through a cache that has one or more stored responses
    1239          for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 6</a> of <a href="#Part6" id="rfc.xref.Part6.6"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1334         for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 6</a> of <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    12401335      </p>
    12411336      <h3 id="rfc.section.4.3.5"><a href="#rfc.section.4.3.5">4.3.5</a>&nbsp;<a id="DELETE" href="#DELETE">DELETE</a></h3>
    … …  
    12531348      </p>
    12541349      <p id="rfc.section.4.3.5.p.4">Responses to the DELETE method are not cacheable. If a DELETE request passes through a cache that has one or more stored responses
    1255          for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 6</a> of <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1350         for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 6</a> of <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    12561351      </p>
    12571352      <div id="rfc.iref.c.3"></div>
    … …  
    12641359         For example,
    12651360      </p>
    1266       <div id="rfc.figure.u.3"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
     1361      <div id="rfc.figure.u.4"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
    12671362Host: server.example.com:80
    12681363
    … …  
    12771372      </p>
    12781373      <p id="rfc.section.4.3.6.p.7">Proxy authentication might be used to establish the authority to create a tunnel:</p>
    1279       <div id="rfc.figure.u.4"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
     1374      <div id="rfc.figure.u.5"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
    12801375Host: server.example.com:80
    12811376Proxy-Authorization: basic aGVsbG86d29ybGQ=
    … …  
    13181413         but might be defined by future extensions to HTTP. Content negotiation <em class="bcp14">MAY</em> be used to select the appropriate response format. If no response body is included, the response <em class="bcp14">MUST</em> include a <a href="p1-messaging.html#header.content-length" class="smpl">Content-Length</a> field with a field-value of "0".
    13191414      </p>
    1320       <p id="rfc.section.4.3.7.p.7">The <a href="#header.max-forwards" class="smpl">Max-Forwards</a> header field <em class="bcp14">MAY</em> be used to target a specific proxy in the request chain (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.1" title="Max-Forwards">Section&nbsp;11.14</a>). If no Max-Forwards field is present in the request, then the forwarded request <em class="bcp14">MUST NOT</em> include a Max-Forwards field.
     1415      <p id="rfc.section.4.3.7.p.7">The <a href="#header.max-forwards" class="smpl">Max-Forwards</a> header field <em class="bcp14">MAY</em> be used to target a specific proxy in the request chain (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.1" title="Max-Forwards">Section&nbsp;10.14</a>). If no Max-Forwards field is present in the request, then the forwarded request <em class="bcp14">MUST NOT</em> include a Max-Forwards field.
    13211416      </p>
    13221417      <h3 id="rfc.section.4.3.8"><a href="#rfc.section.4.3.8">4.3.8</a>&nbsp;<a id="TRACE" href="#TRACE">TRACE</a></h3>
    13231418      <div id="rfc.iref.t.1"></div>
    13241419      <div id="rfc.iref.m.8"></div>
    1325       <p id="rfc.section.4.3.8.p.1">The TRACE method requests a remote, application-layer loop-back of the request message. The final recipient of the request <em class="bcp14">SHOULD</em> reflect the message received back to the client as the message body of a <a href="#status.200" class="smpl">200 (OK)</a> response. The final recipient is either the origin server or the first proxy to receive a <a href="#header.max-forwards" class="smpl">Max-Forwards</a> value of zero (0) in the request (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.2" title="Max-Forwards">Section&nbsp;11.14</a>). A TRACE request <em class="bcp14">MUST NOT</em> include a message body.
     1420      <p id="rfc.section.4.3.8.p.1">The TRACE method requests a remote, application-layer loop-back of the request message. The final recipient of the request <em class="bcp14">SHOULD</em> reflect the message received back to the client as the message body of a <a href="#status.200" class="smpl">200 (OK)</a> response. The final recipient is either the origin server or the first proxy to receive a <a href="#header.max-forwards" class="smpl">Max-Forwards</a> value of zero (0) in the request (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.2" title="Max-Forwards">Section&nbsp;10.14</a>). A TRACE request <em class="bcp14">MUST NOT</em> include a message body.
    13261421      </p>
    13271422      <p id="rfc.section.4.3.8.p.2">TRACE allows the client to see what is being received at the other end of the request chain and use that data for testing
    … …  
    13541449               <tr>
    13551450                  <td class="left">Max-Forwards</td>
    1356                   <td class="left"><a href="#header.max-forwards" id="rfc.xref.header.max-forwards.3" title="Max-Forwards">Section&nbsp;11.14</a></td>
     1451                  <td class="left"><a href="#header.max-forwards" id="rfc.xref.header.max-forwards.3" title="Max-Forwards">Section&nbsp;10.14</a></td>
    13571452               </tr>
    13581453               <tr>
    13591454                  <td class="left">Expect</td>
    1360                   <td class="left"><a href="#header.expect" id="rfc.xref.header.expect.1" title="Expect">Section&nbsp;11.11</a></td>
     1455                  <td class="left"><a href="#header.expect" id="rfc.xref.header.expect.1" title="Expect">Section&nbsp;10.11</a></td>
    13611456               </tr>
    13621457               <tr>
    … …  
    14161511               <tr>
    14171512                  <td class="left">Accept</td>
    1418                   <td class="left"><a href="#header.accept" id="rfc.xref.header.accept.1" title="Accept">Section&nbsp;11.1</a></td>
     1513                  <td class="left"><a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Section&nbsp;10.1</a></td>
    14191514               </tr>
    14201515               <tr>
    14211516                  <td class="left">Accept-Charset</td>
    1422                   <td class="left"><a href="#header.accept-charset" id="rfc.xref.header.accept-charset.1" title="Accept-Charset">Section&nbsp;11.2</a></td>
     1517                  <td class="left"><a href="#header.accept-charset" id="rfc.xref.header.accept-charset.2" title="Accept-Charset">Section&nbsp;10.2</a></td>
    14231518               </tr>
    14241519               <tr>
    14251520                  <td class="left">Accept-Encoding</td>
    1426                   <td class="left"><a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.1" title="Accept-Encoding">Section&nbsp;11.3</a></td>
     1521                  <td class="left"><a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.2" title="Accept-Encoding">Section&nbsp;10.3</a></td>
    14271522               </tr>
    14281523               <tr>
    14291524                  <td class="left">Accept-Language</td>
    1430                   <td class="left"><a href="#header.accept-language" id="rfc.xref.header.accept-language.1" title="Accept-Language">Section&nbsp;11.4</a></td>
     1525                  <td class="left"><a href="#header.accept-language" id="rfc.xref.header.accept-language.2" title="Accept-Language">Section&nbsp;10.4</a></td>
    14311526               </tr>
    14321527            </tbody>
    … …  
    14661561               <tr>
    14671562                  <td class="left">From</td>
    1468                   <td class="left"><a href="#header.from" id="rfc.xref.header.from.1" title="From">Section&nbsp;11.12</a></td>
     1563                  <td class="left"><a href="#header.from" id="rfc.xref.header.from.1" title="From">Section&nbsp;10.12</a></td>
    14691564               </tr>
    14701565               <tr>
    14711566                  <td class="left">Referer</td>
    1472                   <td class="left"><a href="#header.referer" id="rfc.xref.header.referer.1" title="Referer">Section&nbsp;11.15</a></td>
     1567                  <td class="left"><a href="#header.referer" id="rfc.xref.header.referer.1" title="Referer">Section&nbsp;10.15</a></td>
    14731568               </tr>
    14741569               <tr>
    … …  
    14781573               <tr>
    14791574                  <td class="left">User-Agent</td>
    1480                   <td class="left"><a href="#header.user-agent" id="rfc.xref.header.user-agent.1" title="User-Agent">Section&nbsp;11.18</a></td>
     1575                  <td class="left"><a href="#header.user-agent" id="rfc.xref.header.user-agent.2" title="User-Agent">Section&nbsp;10.18</a></td>
    14811576               </tr>
    14821577            </tbody>
    … …  
    15061601         </li>
    15071602      </ul>
    1508       <p id="rfc.section.6.p.4">For most status codes the response can carry a payload, in which case a <a href="#header.content-type" class="smpl">Content-Type</a> header field indicates the payload's media type (<a href="#header.content-type" id="rfc.xref.header.content-type.2" title="Content-Type">Section&nbsp;11.9</a>).
     1603      <p id="rfc.section.6.p.4">For most status codes the response can carry a payload, in which case a <a href="#header.content-type" class="smpl">Content-Type</a> header field indicates the payload's media type (<a href="#header.content-type" id="rfc.xref.header.content-type.2" title="Content-Type">Section&nbsp;10.9</a>).
    15091604      </p>
    15101605      <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a id="overview.of.status.codes" href="#overview.of.status.codes">Overview of Status Codes</a></h2>
    … …  
    17321827      <p id="rfc.section.6.1.p.2">Note that this list is not exhaustive — it does not include extension status codes defined in other specifications.</p>
    17331828      <h2 id="rfc.section.6.2"><a href="#rfc.section.6.2">6.2</a>&nbsp;<a id="status.1xx" href="#status.1xx">Informational 1xx</a></h2>
    1734       <div id="rfc.iref.23"></div>
     1829      <div id="rfc.iref.25"></div>
    17351830      <div id="rfc.iref.s.3"></div>
    17361831      <p id="rfc.section.6.2.p.1">This class of status code indicates a provisional response, consisting only of the status-line and optional header fields,
    … …  
    17451840         a request, then it need not forward the corresponding <a href="#status.100" class="smpl">100 (Continue)</a> response(s).)
    17461841      </p>
    1747       <div id="rfc.iref.24"></div>
     1842      <div id="rfc.iref.26"></div>
    17481843      <div id="rfc.iref.s.4"></div>
    17491844      <h3 id="rfc.section.6.2.1"><a href="#rfc.section.6.2.1">6.2.1</a>&nbsp;<a id="status.100" href="#status.100">100 Continue</a></h3>
    … …  
    17521847         server <em class="bcp14">MUST</em> send a final response after the request has been completed. See <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1.15"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a> for detailed discussion of the use and handling of this status code.
    17531848      </p>
    1754       <div id="rfc.iref.25"></div>
     1849      <div id="rfc.iref.27"></div>
    17551850      <div id="rfc.iref.s.5"></div>
    17561851      <h3 id="rfc.section.6.2.2"><a href="#rfc.section.6.2.2">6.2.2</a>&nbsp;<a id="status.101" href="#status.101">101 Switching Protocols</a></h3>
    … …  
    17631858      </p>
    17641859      <h2 id="rfc.section.6.3"><a href="#rfc.section.6.3">6.3</a>&nbsp;<a id="status.2xx" href="#status.2xx">Successful 2xx</a></h2>
    1765       <div id="rfc.iref.26"></div>
     1860      <div id="rfc.iref.28"></div>
    17661861      <div id="rfc.iref.s.6"></div>
    17671862      <p id="rfc.section.6.3.p.1">This class of status code indicates that the client's request was successfully received, understood, and accepted.</p>
    1768       <div id="rfc.iref.27"></div>
     1863      <div id="rfc.iref.29"></div>
    17691864      <div id="rfc.iref.s.7"></div>
    17701865      <h3 id="rfc.section.6.3.1"><a href="#rfc.section.6.3.1">6.3.1</a>&nbsp;<a id="status.200" href="#status.200">200 OK</a></h3>
    … …  
    17801875         <dd>a representation containing the request message as received by the end server.</dd>
    17811876      </dl>
    1782       <p id="rfc.section.6.3.1.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 200 responses.
    1783       </p>
    1784       <div id="rfc.iref.28"></div>
     1877      <p id="rfc.section.6.3.1.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 200 responses.
     1878      </p>
     1879      <div id="rfc.iref.30"></div>
    17851880      <div id="rfc.iref.s.8"></div>
    17861881      <h3 id="rfc.section.6.3.2"><a href="#rfc.section.6.3.2">6.3.2</a>&nbsp;<a id="status.201" href="#status.201">201 Created</a></h3>
    … …  
    17951890         the <a href="#header.location" class="smpl">Location</a> header field or, in case the Location header field was omitted, by the Effective Request URI (see <a href="p4-conditional.html#header.etag" title="ETag">Section 2.3</a> of <a href="#Part4" id="rfc.xref.Part4.12"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>).
    17961891      </p>
    1797       <div id="rfc.iref.29"></div>
     1892      <div id="rfc.iref.31"></div>
    17981893      <div id="rfc.iref.s.9"></div>
    17991894      <h3 id="rfc.section.6.3.3"><a href="#rfc.section.6.3.3">6.3.3</a>&nbsp;<a id="status.202" href="#status.202">202 Accepted</a></h3>
    … …  
    18071902         user can expect the request to be fulfilled.
    18081903      </p>
    1809       <div id="rfc.iref.30"></div>
     1904      <div id="rfc.iref.32"></div>
    18101905      <div id="rfc.iref.s.10"></div>
    18111906      <h3 id="rfc.section.6.3.4"><a href="#rfc.section.6.3.4">6.3.4</a>&nbsp;<a id="status.203" href="#status.203">203 Non-Authoritative Information</a></h3>
    1812       <p id="rfc.section.6.3.4.p.1">The representation in the response has been transformed or otherwise modified by a transforming proxy (<a href="p1-messaging.html#intermediaries" title="Intermediaries">Section 2.3</a> of <a href="#Part1" id="rfc.xref.Part1.17"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>). Note that the behavior of transforming intermediaries is controlled by the no-transform Cache-Control directive (<a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 7.2</a> of <a href="#Part6" id="rfc.xref.Part6.9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1907      <p id="rfc.section.6.3.4.p.1">The representation in the response has been transformed or otherwise modified by a transforming proxy (<a href="p1-messaging.html#intermediaries" title="Intermediaries">Section 2.3</a> of <a href="#Part1" id="rfc.xref.Part1.17"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>). Note that the behavior of transforming intermediaries is controlled by the no-transform Cache-Control directive (<a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 7.2</a> of <a href="#Part6" id="rfc.xref.Part6.10"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    18131908      </p>
    18141909      <p id="rfc.section.6.3.4.p.2">This status code is only appropriate when the response status code would have been <a href="#status.200" class="smpl">200 (OK)</a> otherwise. When the status code before transformation would have been different, the 214 Transformation Applied warn-code
    1815          (<a href="p6-cache.html#header.warning" title="Warning">Section 7.6</a> of <a href="#Part6" id="rfc.xref.Part6.10"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) is appropriate.
    1816       </p>
    1817       <p id="rfc.section.6.3.4.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.11"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 203 responses.
    1818       </p>
    1819       <div id="rfc.iref.31"></div>
     1910         (<a href="p6-cache.html#header.warning" title="Warning">Section 7.6</a> of <a href="#Part6" id="rfc.xref.Part6.11"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) is appropriate.
     1911      </p>
     1912      <p id="rfc.section.6.3.4.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.12"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 203 responses.
     1913      </p>
     1914      <div id="rfc.iref.33"></div>
    18201915      <div id="rfc.iref.s.11"></div>
    18211916      <h3 id="rfc.section.6.3.5"><a href="#rfc.section.6.3.5">6.3.5</a>&nbsp;<a id="status.204" href="#status.204">204 No Content</a></h3>
    … …  
    18381933      <p id="rfc.section.6.3.5.p.5">The 204 response <em class="bcp14">MUST NOT</em> include a message body, and thus is always terminated by the first empty line after the header fields.
    18391934      </p>
    1840       <div id="rfc.iref.32"></div>
     1935      <div id="rfc.iref.34"></div>
    18411936      <div id="rfc.iref.s.12"></div>
    18421937      <h3 id="rfc.section.6.3.6"><a href="#rfc.section.6.3.6">6.3.6</a>&nbsp;<a id="status.205" href="#status.205">205 Reset Content</a></h3>
    … …  
    18481943      </p>
    18491944      <h2 id="rfc.section.6.4"><a href="#rfc.section.6.4">6.4</a>&nbsp;<a id="status.3xx" href="#status.3xx">Redirection 3xx</a></h2>
    1850       <div id="rfc.iref.33"></div>
     1945      <div id="rfc.iref.35"></div>
    18511946      <div id="rfc.iref.s.13"></div>
    18521947      <p id="rfc.section.6.4.p.1">This class of status code indicates that further action needs to be taken by the user agent in order to fulfill the request.
    … …  
    18681963         </li>
    18691964         <li>
    1870             <p>Redirection offering a choice of matching resources for use by agent-driven content negotiation (<a href="#agent-driven.negotiation" title="Agent-driven Negotiation">Section&nbsp;10.2</a>). This is status code <a href="#status.300" class="smpl">300 (Multiple Choices)</a>.
     1965            <p>Redirection offering a choice of matching resources for use by agent-driven content negotiation (<a href="#agent-driven.negotiation" title="Agent-driven Negotiation">Section&nbsp;3.4.2</a>). This is status code <a href="#status.300" class="smpl">300 (Multiple Choices)</a>.
    18711966            </p>
    18721967         </li>
    … …  
    18831978         </p>
    18841979      </div>
    1885       <p id="rfc.section.6.4.p.4">A <a href="#header.location" class="smpl">Location</a> header field on a 3xx response indicates that a client <em class="bcp14">MAY</em> automatically redirect to the URI provided; see <a href="#header.location" id="rfc.xref.header.location.2" title="Location">Section&nbsp;11.13</a>.
     1980      <p id="rfc.section.6.4.p.4">A <a href="#header.location" class="smpl">Location</a> header field on a 3xx response indicates that a client <em class="bcp14">MAY</em> automatically redirect to the URI provided; see <a href="#header.location" id="rfc.xref.header.location.2" title="Location">Section&nbsp;10.13</a>.
    18861981      </p>
    18871982      <p id="rfc.section.6.4.p.5">Note that for methods not known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;4.2.1</a>, automatic redirection needs to done with care, since the redirect might change the conditions under which the request was
    … …  
    18941989         </p>
    18951990      </div>
    1896       <div id="rfc.iref.34"></div>
     1991      <div id="rfc.iref.36"></div>
    18971992      <div id="rfc.iref.s.14"></div>
    18981993      <h3 id="rfc.section.6.4.1"><a href="#rfc.section.6.4.1">6.4.1</a>&nbsp;<a id="status.300" href="#status.300">300 Multiple Choices</a></h3>
    18991994      <p id="rfc.section.6.4.1.p.1">The target resource has more than one representation, each with its own specific location, and agent-driven negotiation information
    1900          (<a href="#content.negotiation" title="Content Negotiation">Section&nbsp;10</a>) is being provided so that the user (or user agent) can select a preferred representation by redirecting its request to that
     1995         (<a href="#content.negotiation" title="Content Negotiation">Section&nbsp;3.4</a>) is being provided so that the user (or user agent) can select a preferred representation by redirecting its request to that
    19011996         location.
    19021997      </p>
    … …  
    19072002      <p id="rfc.section.6.4.1.p.3">If the server has a preferred choice of representation, it <em class="bcp14">SHOULD</em> include the specific URI for that representation in the <a href="#header.location" class="smpl">Location</a> field; user agents <em class="bcp14">MAY</em> use the Location field value for automatic redirection.
    19082003      </p>
    1909       <p id="rfc.section.6.4.1.p.4">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.12"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 300 responses.
    1910       </p>
    1911       <div id="rfc.iref.35"></div>
     2004      <p id="rfc.section.6.4.1.p.4">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.13"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 300 responses.
     2005      </p>
     2006      <div id="rfc.iref.37"></div>
    19122007      <div id="rfc.iref.s.15"></div>
    19132008      <h3 id="rfc.section.6.4.2"><a href="#rfc.section.6.4.2">6.4.2</a>&nbsp;<a id="status.301" href="#status.301">301 Moved Permanently</a></h3>
    … …  
    19152010         request URI to one or more of the new references returned by the server, where possible.
    19162011      </p>
    1917       <p id="rfc.section.6.4.2.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.13"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 301 responses.
     2012      <p id="rfc.section.6.4.2.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.14"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 301 responses.
    19182013      </p>
    19192014      <p id="rfc.section.6.4.2.p.3">The new permanent URI <em class="bcp14">SHOULD</em> be given by the <a href="#header.location" class="smpl">Location</a> field in the response. A response payload can contain a short hypertext note with a hyperlink to the new URI(s).
    … …  
    19232018         </p>
    19242019      </div>
    1925       <div id="rfc.iref.36"></div>
     2020      <div id="rfc.iref.38"></div>
    19262021      <div id="rfc.iref.s.16"></div>
    19272022      <h3 id="rfc.section.6.4.3"><a href="#rfc.section.6.4.3">6.4.3</a>&nbsp;<a id="status.302" href="#status.302">302 Found</a></h3>
    … …  
    19342029         </p>
    19352030      </div>
    1936       <div id="rfc.iref.37"></div>
     2031      <div id="rfc.iref.39"></div>
    19372032      <div id="rfc.iref.s.17"></div>
    19382033      <h3 id="rfc.section.6.4.4"><a href="#rfc.section.6.4.4">6.4.4</a>&nbsp;<a id="status.303" href="#status.303">303 See Other</a></h3>
    … …  
    19552050      <p id="rfc.section.6.4.4.p.4">Except for responses to a HEAD request, the representation of a 303 response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the <a href="#header.location" class="smpl">Location</a> URI.
    19562051      </p>
    1957       <div id="rfc.iref.38"></div>
     2052      <div id="rfc.iref.40"></div>
    19582053      <div id="rfc.iref.s.18"></div>
    19592054      <h3 id="rfc.section.6.4.5"><a href="#rfc.section.6.4.5">6.4.5</a>&nbsp;<a id="status.305" href="#status.305">305 Use Proxy</a></h3>
    19602055      <p id="rfc.section.6.4.5.p.1">The 305 status code was defined in a previous version of this specification (see <a href="#changes.from.rfc.2616" title="Changes from RFC 2616">Appendix&nbsp;C</a>), and is now deprecated.
    19612056      </p>
    1962       <div id="rfc.iref.39"></div>
     2057      <div id="rfc.iref.41"></div>
    19632058      <div id="rfc.iref.s.19"></div>
    19642059      <h3 id="rfc.section.6.4.6"><a href="#rfc.section.6.4.6">6.4.6</a>&nbsp;<a id="status.306" href="#status.306">306 (Unused)</a></h3>
    19652060      <p id="rfc.section.6.4.6.p.1">The 306 status code was used in a previous version of the specification, is no longer used, and the code is reserved.</p>
    1966       <div id="rfc.iref.40"></div>
     2061      <div id="rfc.iref.42"></div>
    19672062      <div id="rfc.iref.s.20"></div>
    19682063      <h3 id="rfc.section.6.4.7"><a href="#rfc.section.6.4.7">6.4.7</a>&nbsp;<a id="status.307" href="#status.307">307 Temporary Redirect</a></h3>
    … …  
    19782073      </div>
    19792074      <h2 id="rfc.section.6.5"><a href="#rfc.section.6.5">6.5</a>&nbsp;<a id="status.4xx" href="#status.4xx">Client Error 4xx</a></h2>
    1980       <div id="rfc.iref.41"></div>
     2075      <div id="rfc.iref.43"></div>
    19812076      <div id="rfc.iref.s.21"></div>
    19822077      <p id="rfc.section.6.5.p.1">The 4xx class of status code is intended for cases in which the client seems to have erred. Except when responding to a HEAD
    … …  
    19842079         These status codes are applicable to any request method. User agents <em class="bcp14">SHOULD</em> display any included representation to the user.
    19852080      </p>
    1986       <div id="rfc.iref.42"></div>
     2081      <div id="rfc.iref.44"></div>
    19872082      <div id="rfc.iref.s.22"></div>
    19882083      <h3 id="rfc.section.6.5.1"><a href="#rfc.section.6.5.1">6.5.1</a>&nbsp;<a id="status.400" href="#status.400">400 Bad Request</a></h3>
    19892084      <p id="rfc.section.6.5.1.p.1">The server cannot or will not process the request, due to a client error (e.g., malformed syntax).</p>
    1990       <div id="rfc.iref.43"></div>
     2085      <div id="rfc.iref.45"></div>
    19912086      <div id="rfc.iref.s.23"></div>
    19922087      <h3 id="rfc.section.6.5.2"><a href="#rfc.section.6.5.2">6.5.2</a>&nbsp;<a id="status.402" href="#status.402">402 Payment Required</a></h3>
    19932088      <p id="rfc.section.6.5.2.p.1">This code is reserved for future use.</p>
    1994       <div id="rfc.iref.44"></div>
     2089      <div id="rfc.iref.46"></div>
    19952090      <div id="rfc.iref.s.24"></div>
    19962091      <h3 id="rfc.section.6.5.3"><a href="#rfc.section.6.5.3">6.5.3</a>&nbsp;<a id="status.403" href="#status.403">403 Forbidden</a></h3>
    … …  
    20022097            (Not Found)</a>  <em class="bcp14">MAY</em> be used instead.
    20032098      </p>
    2004       <div id="rfc.iref.45"></div>
     2099      <div id="rfc.iref.47"></div>
    20052100      <div id="rfc.iref.s.25"></div>
    20062101      <h3 id="rfc.section.6.5.4"><a href="#rfc.section.6.5.4">6.5.4</a>&nbsp;<a id="status.404" href="#status.404">404 Not Found</a></h3>
    … …  
    20102105         has been refused, or when no other response is applicable.
    20112106      </p>
    2012       <div id="rfc.iref.46"></div>
     2107      <div id="rfc.iref.48"></div>
    20132108      <div id="rfc.iref.s.26"></div>
    20142109      <h3 id="rfc.section.6.5.5"><a href="#rfc.section.6.5.5">6.5.5</a>&nbsp;<a id="status.405" href="#status.405">405 Method Not Allowed</a></h3>
    20152110      <p id="rfc.section.6.5.5.p.1">The method specified in the request-line is not allowed for the target resource. The response <em class="bcp14">MUST</em> include an <a href="#header.allow" class="smpl">Allow</a> header field containing a list of valid methods for the requested resource.
    20162111      </p>
    2017       <div id="rfc.iref.47"></div>
     2112      <div id="rfc.iref.49"></div>
    20182113      <div id="rfc.iref.s.27"></div>
    20192114      <h3 id="rfc.section.6.5.6"><a href="#rfc.section.6.5.6">6.5.6</a>&nbsp;<a id="status.406" href="#status.406">406 Not Acceptable</a></h3>
    … …  
    20332128      <p id="rfc.section.6.5.6.p.4">If the response could be unacceptable, a user agent <em class="bcp14">SHOULD</em> temporarily stop receipt of more data and query the user for a decision on further actions.
    20342129      </p>
    2035       <div id="rfc.iref.48"></div>
     2130      <div id="rfc.iref.50"></div>
    20362131      <div id="rfc.iref.s.28"></div>
    20372132      <h3 id="rfc.section.6.5.7"><a href="#rfc.section.6.5.7">6.5.7</a>&nbsp;<a id="status.408" href="#status.408">408 Request Timeout</a></h3>
    20382133      <p id="rfc.section.6.5.7.p.1">The client did not produce a request within the time that the server was prepared to wait. The client <em class="bcp14">MAY</em> repeat the request without modifications at any later time.
    20392134      </p>
    2040       <div id="rfc.iref.49"></div>
     2135      <div id="rfc.iref.51"></div>
    20412136      <div id="rfc.iref.s.29"></div>
    20422137      <h3 id="rfc.section.6.5.8"><a href="#rfc.section.6.5.8">6.5.8</a>&nbsp;<a id="status.409" href="#status.409">409 Conflict</a></h3>
    … …  
    20512146         contain a list of the differences between the two versions.
    20522147      </p>
    2053       <div id="rfc.iref.50"></div>
     2148      <div id="rfc.iref.52"></div>
    20542149      <div id="rfc.iref.s.30"></div>
    20552150      <h3 id="rfc.section.6.5.9"><a href="#rfc.section.6.5.9">6.5.9</a>&nbsp;<a id="status.410" href="#status.410">410 Gone</a></h3>
    … …  
    20642159         — that is left to the discretion of the server owner.
    20652160      </p>
    2066       <p id="rfc.section.6.5.9.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.14"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 410 responses.
    2067       </p>
    2068       <div id="rfc.iref.51"></div>
     2161      <p id="rfc.section.6.5.9.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.15"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 410 responses.
     2162      </p>
     2163      <div id="rfc.iref.53"></div>
    20692164      <div id="rfc.iref.s.31"></div>
    20702165      <h3 id="rfc.section.6.5.10"><a href="#rfc.section.6.5.10">6.5.10</a>&nbsp;<a id="status.411" href="#status.411">411 Length Required</a></h3>
    … …  
    20722167         message.
    20732168      </p>
    2074       <div id="rfc.iref.52"></div>
     2169      <div id="rfc.iref.54"></div>
    20752170      <div id="rfc.iref.s.32"></div>
    20762171      <h3 id="rfc.section.6.5.11"><a href="#rfc.section.6.5.11">6.5.11</a>&nbsp;<a id="status.413" href="#status.413">413 Request Representation Too Large</a></h3>
    … …  
    20802175      <p id="rfc.section.6.5.11.p.2">If the condition is temporary, the server <em class="bcp14">SHOULD</em> include a <a href="#header.retry-after" class="smpl">Retry-After</a> header field to indicate that it is temporary and after what time the client <em class="bcp14">MAY</em> try again.
    20812176      </p>
    2082       <div id="rfc.iref.53"></div>
     2177      <div id="rfc.iref.55"></div>
    20832178      <div id="rfc.iref.s.33"></div>
    20842179      <h3 id="rfc.section.6.5.12"><a href="#rfc.section.6.5.12">6.5.12</a>&nbsp;<a id="status.414" href="#status.414">414 URI Too Long</a></h3>
    … …  
    20892184         in some servers using fixed-length buffers for reading or manipulating the request-target.
    20902185      </p>
    2091       <div id="rfc.iref.54"></div>
     2186      <div id="rfc.iref.56"></div>
    20922187      <div id="rfc.iref.s.34"></div>
    20932188      <h3 id="rfc.section.6.5.13"><a href="#rfc.section.6.5.13">6.5.13</a>&nbsp;<a id="status.415" href="#status.415">415 Unsupported Media Type</a></h3>
    … …  
    20952190         on the target resource.
    20962191      </p>
    2097       <div id="rfc.iref.55"></div>
     2192      <div id="rfc.iref.57"></div>
    20982193      <div id="rfc.iref.s.35"></div>
    20992194      <h3 id="rfc.section.6.5.14"><a href="#rfc.section.6.5.14">6.5.14</a>&nbsp;<a id="status.417" href="#status.417">417 Expectation Failed</a></h3>
    2100       <p id="rfc.section.6.5.14.p.1">The expectation given in an <a href="#header.expect" class="smpl">Expect</a> header field (see <a href="#header.expect" id="rfc.xref.header.expect.2" title="Expect">Section&nbsp;11.11</a>) could not be met by this server, or, if the server is a proxy, the server has unambiguous evidence that the request could
     2195      <p id="rfc.section.6.5.14.p.1">The expectation given in an <a href="#header.expect" class="smpl">Expect</a> header field (see <a href="#header.expect" id="rfc.xref.header.expect.2" title="Expect">Section&nbsp;10.11</a>) could not be met by this server, or, if the server is a proxy, the server has unambiguous evidence that the request could
    21012196         not be met by the next-hop server.
    21022197      </p>
    2103       <div id="rfc.iref.56"></div>
     2198      <div id="rfc.iref.58"></div>
    21042199      <div id="rfc.iref.s.36"></div>
    21052200      <h3 id="rfc.section.6.5.15"><a href="#rfc.section.6.5.15">6.5.15</a>&nbsp;<a id="status.426" href="#status.426">426 Upgrade Required</a></h3>
    21062201      <p id="rfc.section.6.5.15.p.1">The request can not be completed without a prior protocol upgrade. This response <em class="bcp14">MUST</em> include an <a href="p1-messaging.html#header.upgrade" class="smpl">Upgrade</a> header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 6.4</a> of <a href="#Part1" id="rfc.xref.Part1.19"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) specifying the required protocols.
    21072202      </p>
    2108       <div id="rfc.figure.u.5"></div>
     2203      <div id="rfc.figure.u.6"></div>
    21092204      <p>Example:</p>  <pre class="text">HTTP/1.1 426 Upgrade Required
    21102205Upgrade: HTTP/3.0
    … …  
    21182213      </p>
    21192214      <h2 id="rfc.section.6.6"><a href="#rfc.section.6.6">6.6</a>&nbsp;<a id="status.5xx" href="#status.5xx">Server Error 5xx</a></h2>
    2120       <div id="rfc.iref.57"></div>
     2215      <div id="rfc.iref.59"></div>
    21212216      <div id="rfc.iref.s.37"></div>
    21222217      <p id="rfc.section.6.6.p.1">Response status codes beginning with the digit "5" indicate cases in which the server is aware that it has erred or is incapable
    … …  
    21242219         User agents <em class="bcp14">SHOULD</em> display any included representation to the user. These response codes are applicable to any request method.
    21252220      </p>
    2126       <div id="rfc.iref.58"></div>
     2221      <div id="rfc.iref.60"></div>
    21272222      <div id="rfc.iref.s.38"></div>
    21282223      <h3 id="rfc.section.6.6.1"><a href="#rfc.section.6.6.1">6.6.1</a>&nbsp;<a id="status.500" href="#status.500">500 Internal Server Error</a></h3>
    21292224      <p id="rfc.section.6.6.1.p.1">The server encountered an unexpected condition which prevented it from fulfilling the request.</p>
    2130       <div id="rfc.iref.59"></div>
     2225      <div id="rfc.iref.61"></div>
    21312226      <div id="rfc.iref.s.39"></div>
    21322227      <h3 id="rfc.section.6.6.2"><a href="#rfc.section.6.6.2">6.6.2</a>&nbsp;<a id="status.501" href="#status.501">501 Not Implemented</a></h3>
    … …  
    21342229         does not recognize the request method and is not capable of supporting it for any resource.
    21352230      </p>
    2136       <div id="rfc.iref.60"></div>
     2231      <div id="rfc.iref.62"></div>
    21372232      <div id="rfc.iref.s.40"></div>
    21382233      <h3 id="rfc.section.6.6.3"><a href="#rfc.section.6.6.3">6.6.3</a>&nbsp;<a id="status.502" href="#status.502">502 Bad Gateway</a></h3>
    … …  
    21402235         to fulfill the request.
    21412236      </p>
    2142       <div id="rfc.iref.61"></div>
     2237      <div id="rfc.iref.63"></div>
    21432238      <div id="rfc.iref.s.41"></div>
    21442239      <h3 id="rfc.section.6.6.4"><a href="#rfc.section.6.6.4">6.6.4</a>&nbsp;<a id="status.503" href="#status.503">503 Service Unavailable</a></h3>
    21452240      <p id="rfc.section.6.6.4.p.1">The server is currently unable to handle the request due to a temporary overloading or maintenance of the server.</p>
    21462241      <p id="rfc.section.6.6.4.p.2">The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the
    2147          delay <em class="bcp14">MAY</em> be indicated in a <a href="#header.retry-after" class="smpl">Retry-After</a> header field (<a href="#header.retry-after" id="rfc.xref.header.retry-after.1" title="Retry-After">Section&nbsp;11.16</a>). If no Retry-After is given, the client <em class="bcp14">SHOULD</em> handle the response as it would for a <a href="#status.500" class="smpl">500 (Internal
     2242         delay <em class="bcp14">MAY</em> be indicated in a <a href="#header.retry-after" class="smpl">Retry-After</a> header field (<a href="#header.retry-after" id="rfc.xref.header.retry-after.1" title="Retry-After">Section&nbsp;10.16</a>). If no Retry-After is given, the client <em class="bcp14">SHOULD</em> handle the response as it would for a <a href="#status.500" class="smpl">500 (Internal
    21482243            Server Error)</a> response.
    21492244      </p>
    … …  
    21532248         </p>
    21542249      </div>
    2155       <div id="rfc.iref.62"></div>
     2250      <div id="rfc.iref.64"></div>
    21562251      <div id="rfc.iref.s.42"></div>
    21572252      <h3 id="rfc.section.6.6.5"><a href="#rfc.section.6.6.5">6.6.5</a>&nbsp;<a id="status.504" href="#status.504">504 Gateway Timeout</a></h3>
    … …  
    21642259         </p>
    21652260      </div>
    2166       <div id="rfc.iref.63"></div>
     2261      <div id="rfc.iref.65"></div>
    21672262      <div id="rfc.iref.s.43"></div>
    21682263      <h3 id="rfc.section.6.6.6"><a href="#rfc.section.6.6.6">6.6.6</a>&nbsp;<a id="status.505" href="#status.505">505 HTTP Version Not Supported</a></h3>
    … …  
    21902285               <tr>
    21912286                  <td class="left">Age</td>
    2192                   <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 7.1</a> of <a href="#Part6" id="rfc.xref.Part6.15"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
     2287                  <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 7.1</a> of <a href="#Part6" id="rfc.xref.Part6.16"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
    21932288               </tr>
    21942289               <tr>
    21952290                  <td class="left">Allow</td>
    2196                   <td class="left"><a href="#header.allow" id="rfc.xref.header.allow.2" title="Allow">Section&nbsp;11.5</a></td>
     2291                  <td class="left"><a href="#header.allow" id="rfc.xref.header.allow.2" title="Allow">Section&nbsp;10.5</a></td>
    21972292               </tr>
    21982293               <tr>
    21992294                  <td class="left">Date</td>
    2200                   <td class="left"><a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section&nbsp;11.10</a></td>
     2295                  <td class="left"><a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section&nbsp;10.10</a></td>
    22012296               </tr>
    22022297               <tr>
    … …  
    22062301               <tr>
    22072302                  <td class="left">Location</td>
    2208                   <td class="left"><a href="#header.location" id="rfc.xref.header.location.3" title="Location">Section&nbsp;11.13</a></td>
     2303                  <td class="left"><a href="#header.location" id="rfc.xref.header.location.3" title="Location">Section&nbsp;10.13</a></td>
    22092304               </tr>
    22102305               <tr>
    … …  
    22142309               <tr>
    22152310                  <td class="left">Retry-After</td>
    2216                   <td class="left"><a href="#header.retry-after" id="rfc.xref.header.retry-after.2" title="Retry-After">Section&nbsp;11.16</a></td>
     2311                  <td class="left"><a href="#header.retry-after" id="rfc.xref.header.retry-after.2" title="Retry-After">Section&nbsp;10.16</a></td>
    22172312               </tr>
    22182313               <tr>
    22192314                  <td class="left">Server</td>
    2220                   <td class="left"><a href="#header.server" id="rfc.xref.header.server.1" title="Server">Section&nbsp;11.17</a></td>
     2315                  <td class="left"><a href="#header.server" id="rfc.xref.header.server.1" title="Server">Section&nbsp;10.17</a></td>
    22212316               </tr>
    22222317               <tr>
    22232318                  <td class="left">Vary</td>
    2224                   <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.16"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
     2319                  <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.17"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
    22252320               </tr>
    22262321               <tr>
    … …  
    22362331         a fixed-length subset of that defined by <a href="#RFC1123" id="rfc.xref.RFC1123.1"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>:
    22372332      </p>
    2238       <div id="rfc.figure.u.6"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
     2333      <div id="rfc.figure.u.7"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
    22392334</pre><p id="rfc.section.8.1.p.3">The other formats are described here only for compatibility with obsolete implementations.</p>
    2240       <div id="rfc.figure.u.7"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
     2335      <div id="rfc.figure.u.8"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
    22412336Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
    22422337</pre><p id="rfc.section.8.1.p.5">HTTP/1.1 clients and servers that parse a date value <em class="bcp14">MUST</em> accept all three formats (for compatibility with HTTP/1.0), though they <em class="bcp14">MUST</em> only generate the RFC 1123 format for representing HTTP-date values in header fields.
    … …  
    22462341         time zone, and <em class="bcp14">MUST</em> be assumed when reading the asctime format. HTTP-date is case sensitive and <em class="bcp14">MUST NOT</em> include additional whitespace beyond that specifically included as SP in the grammar.
    22472342      </p>
    2248       <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.3"></span>  <a href="#http.date" class="smpl">HTTP-date</a>    = <a href="#preferred.date.format" class="smpl">rfc1123-date</a> / <a href="#obsolete.date.formats" class="smpl">obs-date</a>
     2343      <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.5"></span>  <a href="#http.date" class="smpl">HTTP-date</a>    = <a href="#preferred.date.format" class="smpl">rfc1123-date</a> / <a href="#obsolete.date.formats" class="smpl">obs-date</a>
    22492344</pre><div id="preferred.date.format">
    22502345         <p id="rfc.section.8.1.p.8">                    Preferred format:</p>
    22512346      </div>
    2252       <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span><span id="rfc.iref.g.15"></span>  <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#imported.abnf" class="smpl">SP</a> date1 <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
     2347      <div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.6"></span><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span><span id="rfc.iref.g.15"></span><span id="rfc.iref.g.16"></span><span id="rfc.iref.g.17"></span>  <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#imported.abnf" class="smpl">SP</a> date1 <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
    22532348  ; fixed length subset of the format defined in
    22542349  ; <a href="http://tools.ietf.org/html/rfc1123#section-5.2.14">Section 5.2.14</a> of <a href="#RFC1123" id="rfc.xref.RFC1123.2"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>
    … …  
    22932388         <p id="rfc.section.8.1.p.11">              Obsolete formats:</p>
    22942389      </div>
    2295       <div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.16"></span>  <a href="#obsolete.date.formats" class="smpl">obs-date</a>     = <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> / <a href="#obsolete.date.formats" class="smpl">asctime-date</a>
    2296 </pre><div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.17"></span>  <a href="#obsolete.date.formats" class="smpl">rfc850-date</a>  = <a href="#obsolete.date.formats" class="smpl">day-name-l</a> "," <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date2</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
     2390      <div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.18"></span>  <a href="#obsolete.date.formats" class="smpl">obs-date</a>     = <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> / <a href="#obsolete.date.formats" class="smpl">asctime-date</a>
     2391</pre><div id="rfc.figure.u.12"></div><pre class="inline"><span id="rfc.iref.g.19"></span>  <a href="#obsolete.date.formats" class="smpl">rfc850-date</a>  = <a href="#obsolete.date.formats" class="smpl">day-name-l</a> "," <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date2</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
    22972392  <a href="#obsolete.date.formats" class="smpl">date2</a>        = <a href="#preferred.date.format" class="smpl">day</a> "-" <a href="#preferred.date.format" class="smpl">month</a> "-" 2<a href="#imported.abnf" class="smpl">DIGIT</a>
    22982393                 ; day-month-year (e.g., 02-Jun-82)
    … …  
    23052400         / %x53.61.74.75.72.64.61.79 ; "Saturday", case-sensitive
    23062401         / %x53.75.6E.64.61.79 ; "Sunday", case-sensitive
    2307 </pre><div id="rfc.figure.u.12"></div><pre class="inline"><span id="rfc.iref.g.18"></span>  <a href="#obsolete.date.formats" class="smpl">asctime-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date3</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">year</a>
     2402</pre><div id="rfc.figure.u.13"></div><pre class="inline"><span id="rfc.iref.g.20"></span>  <a href="#obsolete.date.formats" class="smpl">asctime-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date3</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">year</a>
    23082403  <a href="#obsolete.date.formats" class="smpl">date3</a>        = <a href="#preferred.date.format" class="smpl">month</a> <a href="#imported.abnf" class="smpl">SP</a> ( 2<a href="#imported.abnf" class="smpl">DIGIT</a> / ( <a href="#imported.abnf" class="smpl">SP</a> 1<a href="#imported.abnf" class="smpl">DIGIT</a> ))
    23092404                 ; month day (e.g., Jun  2)
    … …  
    23232418         By convention, the products are listed in order of their significance for identifying the application.
    23242419      </p>
    2325       <div id="rfc.figure.u.13"></div><pre class="inline"><span id="rfc.iref.g.19"></span><span id="rfc.iref.g.20"></span>  <a href="#product.tokens" class="smpl">product</a>         = <a href="#imported.abnf" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>]
     2420      <div id="rfc.figure.u.14"></div><pre class="inline"><span id="rfc.iref.g.21"></span><span id="rfc.iref.g.22"></span>  <a href="#product.tokens" class="smpl">product</a>         = <a href="#imported.abnf" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>]
    23262421  <a href="#product.tokens" class="smpl">product-version</a> = <a href="#imported.abnf" class="smpl">token</a>
    23272422</pre><p id="rfc.section.8.2.p.3">Examples:</p>
    2328       <div id="rfc.figure.u.14"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
     2423      <div id="rfc.figure.u.15"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    23292424  Server: Apache/0.8.4
    23302425</pre><p id="rfc.section.8.2.p.5">Product tokens <em class="bcp14">SHOULD</em> be short and to the point. They <em class="bcp14">MUST NOT</em> be used for advertising or other non-essential information. Although any token octet <em class="bcp14">MAY</em> appear in a product-version, this token <em class="bcp14">SHOULD</em> only be used for a version identifier (i.e., successive versions of the same product <em class="bcp14">SHOULD</em> only differ in the product-version portion of the product value).
    … …  
    23372432         </p>
    23382433      </div>
    2339       <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.21"></span>  <a href="#rule.charset" class="smpl">charset</a> = <a href="#imported.abnf" class="smpl">token</a>
     2434      <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.23"></span>  <a href="#rule.charset" class="smpl">charset</a> = <a href="#imported.abnf" class="smpl">token</a>
    23402435</pre><p id="rfc.section.8.3.p.4">Although HTTP allows an arbitrary token to be used as a charset value, any token that has a predefined value within the IANA
    23412436         Character Set registry <em class="bcp14">MUST</em> represent the character encoding defined by that registry. Applications <em class="bcp14">SHOULD</em> limit their use of character encodings to those defined within the IANA registry.
    … …  
    23512446         directly, and only decoded by the recipient.
    23522447      </p>
    2353       <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.22"></span>  <a href="#content.codings" class="smpl">content-coding</a>   = <a href="#imported.abnf" class="smpl">token</a>
    2354 </pre><p id="rfc.section.8.4.p.3">All content-coding values are case-insensitive. HTTP/1.1 uses content-coding values in the <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.2" title="Accept-Encoding">Section&nbsp;11.3</a>) and <a href="#header.content-encoding" class="smpl">Content-Encoding</a> (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.2" title="Content-Encoding">Section&nbsp;11.6</a>) header fields. Although the value describes the content-coding, what is more important is that it indicates what decoding
     2448      <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.24"></span>  <a href="#content.codings" class="smpl">content-coding</a>   = <a href="#imported.abnf" class="smpl">token</a>
     2449</pre><p id="rfc.section.8.4.p.3">All content-coding values are case-insensitive. HTTP/1.1 uses content-coding values in the <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.3" title="Accept-Encoding">Section&nbsp;10.3</a>) and <a href="#header.content-encoding" class="smpl">Content-Encoding</a> (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.2" title="Content-Encoding">Section&nbsp;10.6</a>) header fields. Although the value describes the content-coding, what is more important is that it indicates what decoding
    23552450         mechanism will be required to remove the encoding.
    23562451      </p>
    … …  
    23672462         </li>
    23682463      </ul>
    2369       <p id="rfc.section.8.4.p.6">gzip<span id="rfc.iref.g.23"></span><span id="rfc.iref.c.7"></span> 
     2464      <p id="rfc.section.8.4.p.6">gzip<span id="rfc.iref.g.25"></span><span id="rfc.iref.c.7"></span> 
    23702465      </p>
    23712466      <ul class="empty">
    … …  
    23742469      </ul>
    23752470      <h2 id="rfc.section.8.5"><a href="#rfc.section.8.5">8.5</a>&nbsp;<a id="media.types" href="#media.types">Media Types</a></h2>
    2376       <p id="rfc.section.8.5.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> in the <a href="#header.content-type" class="smpl">Content-Type</a> (<a href="#header.content-type" id="rfc.xref.header.content-type.3" title="Content-Type">Section&nbsp;11.9</a>) and <a href="#header.accept" class="smpl">Accept</a> (<a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Section&nbsp;11.1</a>) header fields in order to provide open and extensible data typing and type negotiation.
    2377       </p>
    2378       <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.24"></span><span id="rfc.iref.g.25"></span><span id="rfc.iref.g.26"></span>  <a href="#media.types" class="smpl">media-type</a> = <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> *( <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> )
     2471      <p id="rfc.section.8.5.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> in the <a href="#header.content-type" class="smpl">Content-Type</a> (<a href="#header.content-type" id="rfc.xref.header.content-type.3" title="Content-Type">Section&nbsp;10.9</a>) and <a href="#header.accept" class="smpl">Accept</a> (<a href="#header.accept" id="rfc.xref.header.accept.3" title="Accept">Section&nbsp;10.1</a>) header fields in order to provide open and extensible data typing and type negotiation.
     2472      </p>
     2473      <div id="rfc.figure.u.18"></div><pre class="inline"><span id="rfc.iref.g.26"></span><span id="rfc.iref.g.27"></span><span id="rfc.iref.g.28"></span>  <a href="#media.types" class="smpl">media-type</a> = <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> *( <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> )
    23792474  <a href="#media.types" class="smpl">type</a>       = <a href="#imported.abnf" class="smpl">token</a>
    23802475  <a href="#media.types" class="smpl">subtype</a>    = <a href="#imported.abnf" class="smpl">token</a>
    … …  
    23832478         </p>
    23842479      </div>
    2385       <div id="rfc.figure.u.18"></div><pre class="inline"><span id="rfc.iref.g.27"></span><span id="rfc.iref.g.28"></span><span id="rfc.iref.g.29"></span>  <a href="#rule.parameter" class="smpl">parameter</a>      = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a>
     2480      <div id="rfc.figure.u.19"></div><pre class="inline"><span id="rfc.iref.g.29"></span><span id="rfc.iref.g.30"></span><span id="rfc.iref.g.31"></span>  <a href="#rule.parameter" class="smpl">parameter</a>      = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a>
    23862481  <a href="#rule.parameter" class="smpl">attribute</a>      = <a href="#imported.abnf" class="smpl">token</a>
    23872482  <a href="#rule.parameter" class="smpl">value</a>          = <a href="#imported.abnf" class="smpl">word</a>
    … …  
    24332528         of subtags:
    24342529      </p>
    2435       <div id="rfc.figure.u.19"></div><pre class="inline"><span id="rfc.iref.g.30"></span>  <a href="#language.tags" class="smpl">language-tag</a> = &lt;Language-Tag, defined in <a href="#RFC5646" id="rfc.xref.RFC5646.2"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a>, <a href="http://tools.ietf.org/html/rfc5646#section-2.1">Section 2.1</a>&gt;
     2530      <div id="rfc.figure.u.20"></div><pre class="inline"><span id="rfc.iref.g.32"></span>  <a href="#language.tags" class="smpl">language-tag</a> = &lt;Language-Tag, defined in <a href="#RFC5646" id="rfc.xref.RFC5646.2"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a>, <a href="http://tools.ietf.org/html/rfc5646#section-2.1">Section 2.1</a>&gt;
    24362531</pre><p id="rfc.section.8.6.p.4">White space is not allowed within the tag and all tags are case-insensitive. The name space of language subtags is administered
    24372532         by the IANA (see &lt;<a href="http://www.iana.org/assignments/language-subtag-registry">http://www.iana.org/assignments/language-subtag-registry</a>&gt;).
    24382533      </p>
    2439       <div id="rfc.figure.u.20"></div>
     2534      <div id="rfc.figure.u.21"></div>
    24402535      <p>Example tags include:</p>  <pre class="text">  en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN
    24412536</pre> <p id="rfc.section.8.6.p.6">See <a href="#RFC5646" id="rfc.xref.RFC5646.3"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a> for further information.
    … …  
    24782573      <p id="rfc.section.9.2.p.1">A payload body is only present in a message when a message body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.26"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>. The payload body is obtained from the message body by decoding any <a href="p1-messaging.html#header.transfer-encoding" class="smpl">Transfer-Encoding</a> that might have been applied to ensure safe and proper transfer of the message.
    24792574      </p>
    2480       <h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a>&nbsp;<a id="content.negotiation" href="#content.negotiation">Content Negotiation</a></h1>
    2481       <p id="rfc.section.10.p.1">HTTP responses include a representation which contains information for interpretation, whether by a human user or for further
    2482          processing. Often, the server has different ways of representing the same information; for example, in different formats,
    2483          languages, or using different character encodings.
    2484       </p>
    2485       <p id="rfc.section.10.p.2">HTTP clients and their users might have different or variable capabilities, characteristics or preferences which would influence
    2486          which representation, among those available from the server, would be best for the server to deliver. For this reason, HTTP
    2487          provides mechanisms for "content negotiation" — a process of allowing selection of a representation of a given resource, when
    2488          more than one is available.
    2489       </p>
    2490       <p id="rfc.section.10.p.3">This specification defines two patterns of content negotiation; "server-driven", where the server selects the representation
    2491          based upon the client's stated preferences, and "agent-driven" negotiation, where the server provides a list of representations
    2492          for the client to choose from, based upon their metadata. In addition, there are other patterns: some applications use an
    2493          "active content" pattern, where the server returns active content which runs on the client and, based on client available
    2494          parameters, selects additional resources to invoke. "Transparent Content Negotiation" (<a href="#RFC2295" id="rfc.xref.RFC2295.1"><cite title="Transparent Content Negotiation in HTTP">[RFC2295]</cite></a>) has also been proposed.
    2495       </p>
    2496       <p id="rfc.section.10.p.4">These patterns are all widely used, and have trade-offs in applicability and practicality. In particular, when the number
    2497          of preferences or capabilities to be expressed by a client are large (such as when many different formats are supported by
    2498          a user-agent), server-driven negotiation becomes unwieldy, and might not be appropriate. Conversely, when the number of representations
    2499          to choose from is very large, agent-driven negotiation might not be appropriate.
    2500       </p>
    2501       <p id="rfc.section.10.p.5">Note that, in all cases, the supplier of representations has the responsibility for determining which representations might
    2502          be considered to be the "same information".
    2503       </p>
    2504       <h2 id="rfc.section.10.1"><a href="#rfc.section.10.1">10.1</a>&nbsp;<a id="server-driven.negotiation" href="#server-driven.negotiation">Server-driven Negotiation</a></h2>
    2505       <p id="rfc.section.10.1.p.1">If the selection of the best representation for a response is made by an algorithm located at the server, it is called server-driven
    2506          negotiation. Selection is based on the available representations of the response (the dimensions over which it can vary; e.g.,
    2507          language, content-coding, etc.) and the contents of particular header fields in the request message or on other information
    2508          pertaining to the request (such as the network address of the client).
    2509       </p>
    2510       <p id="rfc.section.10.1.p.2">Server-driven negotiation is advantageous when the algorithm for selecting from among the available representations is difficult
    2511          to describe to the user agent, or when the server desires to send its "best guess" to the client along with the first response
    2512          (hoping to avoid the round-trip delay of a subsequent request if the "best guess" is good enough for the user). In order to
    2513          improve the server's guess, the user agent <em class="bcp14">MAY</em> include request header fields (<a href="#header.accept" class="smpl">Accept</a>, <a href="#header.accept-language" class="smpl">Accept-Language</a>, <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a>, etc.) which describe its preferences for such a response.
    2514       </p>
    2515       <p id="rfc.section.10.1.p.3">Server-driven negotiation has disadvantages: </p>
    2516       <ol>
    2517          <li>It is impossible for the server to accurately determine what might be "best" for any given user, since that would require
    2518             complete knowledge of both the capabilities of the user agent and the intended use for the response (e.g., does the user want
    2519             to view it on screen or print it on paper?).
    2520          </li>
    2521          <li>Having the user agent describe its capabilities in every request can be both very inefficient (given that only a small percentage
    2522             of responses have multiple representations) and a potential violation of the user's privacy.
    2523          </li>
    2524          <li>It complicates the implementation of an origin server and the algorithms for generating responses to a request.</li>
    2525          <li>It might limit a public cache's ability to use the same response for multiple user's requests.</li>
    2526       </ol>
    2527       <p id="rfc.section.10.1.p.4">Server-driven negotiation allows the user agent to specify its preferences, but it cannot expect responses to always honor
    2528          them. For example, the origin server might not implement server-driven negotiation, or it might decide that sending a response
    2529          that doesn't conform to them is better than sending a <a href="#status.406" class="smpl">406
    2530             (Not Acceptable)</a> response.
    2531       </p>
    2532       <p id="rfc.section.10.1.p.5">HTTP/1.1 includes the following header fields for enabling server-driven negotiation through description of user agent capabilities
    2533          and user preferences: <a href="#header.accept" class="smpl">Accept</a> (<a href="#header.accept" id="rfc.xref.header.accept.3" title="Accept">Section&nbsp;11.1</a>), <a href="#header.accept-charset" class="smpl">Accept-Charset</a> (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.2" title="Accept-Charset">Section&nbsp;11.2</a>), <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.3" title="Accept-Encoding">Section&nbsp;11.3</a>), <a href="#header.accept-language" class="smpl">Accept-Language</a> (<a href="#header.accept-language" id="rfc.xref.header.accept-language.2" title="Accept-Language">Section&nbsp;11.4</a>), and <a href="#header.user-agent" class="smpl">User-Agent</a> (<a href="#header.user-agent" id="rfc.xref.header.user-agent.2" title="User-Agent">Section&nbsp;11.18</a>). However, an origin server is not limited to these dimensions and <em class="bcp14">MAY</em> vary the response based on any aspect of the request, including aspects of the connection (e.g., IP address) or information
    2534          within extension header fields not defined by this specification.
    2535       </p>
    2536       <div class="note" id="rfc.section.10.1.p.6">
    2537          <p> <b>Note:</b> In practice, <a href="#header.user-agent" class="smpl">User-Agent</a> based negotiation is fragile, because new clients might not be recognized.
    2538          </p>
    2539       </div>
    2540       <p id="rfc.section.10.1.p.7">The <a href="p6-cache.html#header.vary" class="smpl">Vary</a> header field (<a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.17"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) can be used to express the parameters the server uses to select a representation that is subject to server-driven negotiation.
    2541       </p>
    2542       <h2 id="rfc.section.10.2"><a href="#rfc.section.10.2">10.2</a>&nbsp;<a id="agent-driven.negotiation" href="#agent-driven.negotiation">Agent-driven Negotiation</a></h2>
    2543       <p id="rfc.section.10.2.p.1">With agent-driven negotiation, selection of the best representation for a response is performed by the user agent after receiving
    2544          an initial response from the origin server. Selection is based on a list of the available representations of the response
    2545          included within the header fields or body of the initial response, with each representation identified by its own URI. Selection
    2546          from among the representations can be performed automatically (if the user agent is capable of doing so) or manually by the
    2547          user selecting from a generated (possibly hypertext) menu.
    2548       </p>
    2549       <p id="rfc.section.10.2.p.2">Agent-driven negotiation is advantageous when the response would vary over commonly-used dimensions (such as type, language,
    2550          or encoding), when the origin server is unable to determine a user agent's capabilities from examining the request, and generally
    2551          when public caches are used to distribute server load and reduce network usage.
    2552       </p>
    2553       <p id="rfc.section.10.2.p.3">Agent-driven negotiation suffers from the disadvantage of needing a second request to obtain the best alternate representation.
    2554          This second request is only efficient when caching is used. In addition, this specification does not define any mechanism
    2555          for supporting automatic selection, though it also does not prevent any such mechanism from being developed as an extension
    2556          and used within HTTP/1.1.
    2557       </p>
    2558       <p id="rfc.section.10.2.p.4">This specification defines the <a href="#status.300" class="smpl">300 (Multiple Choices)</a> and <a href="#status.406" class="smpl">406 (Not Acceptable)</a> status codes for enabling agent-driven negotiation when the server is unwilling or unable to provide a varying response using
    2559          server-driven negotiation.
    2560       </p>
    2561       <h2 id="rfc.section.10.3"><a href="#rfc.section.10.3">10.3</a>&nbsp;<a id="quality.values" href="#quality.values">Quality Values</a></h2>
    2562       <p id="rfc.section.10.3.p.1">Many of the request header fields for server-driven content negotiation use a common parameter, named "q", to assign a relative
    2563          "weight" to the preference for that associated kind of content. This weight is referred to as a "quality value" (or "qvalue")
    2564          because the same parameter name is often used within server configurations to assign a weight to the relative quality of the
    2565          various representations that can be selected for a resource.
    2566       </p>
    2567       <p id="rfc.section.10.3.p.2">The weight is normalized to a real number in the range 0 through 1, where 0.001 is the least preferred and 1 is the most preferred;
    2568          a value of 0 means "not acceptable". If no "q" parameter is present, the default weight is 1.
    2569       </p>
    2570       <div id="rfc.figure.u.21"></div><pre class="inline"><span id="rfc.iref.g.31"></span><span id="rfc.iref.g.32"></span>  <a href="#quality.values" class="smpl">weight</a> = <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> "q=" <a href="#quality.values" class="smpl">qvalue</a>
    2571   <a href="#quality.values" class="smpl">qvalue</a> = ( "0" [ "." 0*3<a href="#imported.abnf" class="smpl">DIGIT</a> ] )
    2572          / ( "1" [ "." 0*3("0") ] )
    2573 </pre><p id="rfc.section.10.3.p.4">A sender of qvalue <em class="bcp14">MUST NOT</em> generate more than three digits after the decimal point. User configuration of these values ought to be limited in the same
    2574          fashion.
    2575       </p>
    2576       <h1 id="rfc.section.11"><a href="#rfc.section.11">11.</a>&nbsp;<a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1>
    2577       <p id="rfc.section.11.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to request and response semantics and to the
     2575      <h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a>&nbsp;<a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1>
     2576      <p id="rfc.section.10.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to request and response semantics and to the
    25782577         payload of messages.
    25792578      </p>
    25802579      <div id="rfc.iref.a.1"></div>
    25812580      <div id="rfc.iref.h.2"></div>
    2582       <h2 id="rfc.section.11.1"><a href="#rfc.section.11.1">11.1</a>&nbsp;<a id="header.accept" href="#header.accept">Accept</a></h2>
    2583       <p id="rfc.section.11.1.p.1">The "Accept" header field can be used by user agents to specify response media types that are acceptable. Accept header fields
     2581      <h2 id="rfc.section.10.1"><a href="#rfc.section.10.1">10.1</a>&nbsp;<a id="header.accept" href="#header.accept">Accept</a></h2>
     2582      <p id="rfc.section.10.1.p.1">The "Accept" header field can be used by user agents to specify response media types that are acceptable. Accept header fields
    25842583         can be used to indicate that the request is specifically limited to a small set of desired types, as in the case of a request
    25852584         for an in-line image.
    … …  
    25932592  <a href="#header.accept" class="smpl">accept-params</a>  = <a href="#quality.values" class="smpl">weight</a> *( <a href="#header.accept" class="smpl">accept-ext</a> )
    25942593  <a href="#header.accept" class="smpl">accept-ext</a>     = <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> <a href="#imported.abnf" class="smpl">token</a> [ "=" <a href="#imported.abnf" class="smpl">word</a> ]
    2595 </pre><p id="rfc.section.11.1.p.3">The asterisk "*" character is used to group media types into ranges, with "*/*" indicating all media types and "type/*" indicating
     2594</pre><p id="rfc.section.10.1.p.3">The asterisk "*" character is used to group media types into ranges, with "*/*" indicating all media types and "type/*" indicating
    25962595         all subtypes of that type. The media-range <em class="bcp14">MAY</em> include media type parameters that are applicable to that range.
    25972596      </p>
    2598       <p id="rfc.section.11.1.p.4">Each media-range <em class="bcp14">MAY</em> be followed by one or more accept-params, beginning with the "q" parameter for indicating a relative weight, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;10.3</a>. The first "q" parameter (if any) separates the media-range parameter(s) from the accept-params.
    2599       </p>
    2600       <div class="note" id="rfc.section.11.1.p.5">
     2597      <p id="rfc.section.10.1.p.4">Each media-range <em class="bcp14">MAY</em> be followed by one or more accept-params, beginning with the "q" parameter for indicating a relative weight, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;3.4.3</a>. The first "q" parameter (if any) separates the media-range parameter(s) from the accept-params.
     2598      </p>
     2599      <div class="note" id="rfc.section.10.1.p.5">
    26012600         <p> <b>Note:</b> Use of the "q" parameter name to separate media type parameters from Accept extension parameters is due to historical practice.
    26022601            Although this prevents any media type parameter named "q" from being used with a media range, such an event is believed to
    … …  
    26052604         </p>
    26062605      </div>
    2607       <p id="rfc.section.11.1.p.6">The example</p>
     2606      <p id="rfc.section.10.1.p.6">The example</p>
    26082607      <div id="rfc.figure.u.23"></div><pre class="text">  Accept: audio/*; q=0.2, audio/basic
    2609 </pre><p id="rfc.section.11.1.p.8"> <em class="bcp14">SHOULD</em> be interpreted as "I prefer audio/basic, but send me any audio type if it is the best available after an 80% mark-down in
     2608</pre><p id="rfc.section.10.1.p.8"> <em class="bcp14">SHOULD</em> be interpreted as "I prefer audio/basic, but send me any audio type if it is the best available after an 80% mark-down in
    26102609         quality".
    26112610      </p>
    2612       <p id="rfc.section.11.1.p.9">A request without any Accept header field implies that the user agent will accept any media type in response. If an Accept
     2611      <p id="rfc.section.10.1.p.9">A request without any Accept header field implies that the user agent will accept any media type in response. If an Accept
    26132612         header field is present in a request and none of the available representations for the response have a media type that is
    26142613         listed as acceptable, the origin server <em class="bcp14">MAY</em> either honor the Accept header field by sending a <a href="#status.406" class="smpl">406 (Not Acceptable)</a> response or disregard the Accept header field by treating the response as if it is not subject to content negotiation.
    26152614      </p>
    2616       <p id="rfc.section.11.1.p.10">A more elaborate example is</p>
     2615      <p id="rfc.section.10.1.p.10">A more elaborate example is</p>
    26172616      <div id="rfc.figure.u.24"></div><pre class="text">  Accept: text/plain; q=0.5, text/html,
    26182617          text/x-dvi; q=0.8, text/x-c
    2619 </pre><p id="rfc.section.11.1.p.12">Verbally, this would be interpreted as "text/html and text/x-c are the preferred media types, but if they do not exist, then
     2618</pre><p id="rfc.section.10.1.p.12">Verbally, this would be interpreted as "text/html and text/x-c are the preferred media types, but if they do not exist, then
    26202619         send the text/x-dvi representation, and if that does not exist, send the text/plain representation".
    26212620      </p>
    2622       <p id="rfc.section.11.1.p.13">Media ranges can be overridden by more specific media ranges or specific media types. If more than one media range applies
     2621      <p id="rfc.section.10.1.p.13">Media ranges can be overridden by more specific media ranges or specific media types. If more than one media range applies
    26232622         to a given type, the most specific reference has precedence. For example,
    26242623      </p>
    26252624      <div id="rfc.figure.u.25"></div><pre class="text">  Accept: text/*, text/plain, text/plain;format=flowed, */*
    2626 </pre><p id="rfc.section.11.1.p.15">have the following precedence: </p>
     2625</pre><p id="rfc.section.10.1.p.15">have the following precedence: </p>
    26272626      <ol>
    26282627         <li>text/plain;format=flowed</li>
    … …  
    26312630         <li>*/*</li>
    26322631      </ol>
    2633       <p id="rfc.section.11.1.p.16">The media type quality factor associated with a given type is determined by finding the media range with the highest precedence
     2632      <p id="rfc.section.10.1.p.16">The media type quality factor associated with a given type is determined by finding the media range with the highest precedence
    26342633         which matches that type. For example,
    26352634      </p>
    26362635      <div id="rfc.figure.u.26"></div><pre class="text">  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
    26372636          text/html;level=2;q=0.4, */*;q=0.5
    2638 </pre><p id="rfc.section.11.1.p.18">would cause the following values to be associated:</p>
     2637</pre><p id="rfc.section.10.1.p.18">would cause the following values to be associated:</p>
    26392638      <div id="rfc.table.u.11">
    26402639         <table class="tt full left" cellpadding="3" cellspacing="0">
    … …  
    26732672         </table>
    26742673      </div>
    2675       <p id="rfc.section.11.1.p.19"> <b>Note:</b> A user agent might be provided with a default set of quality values for certain media ranges. However, unless the user agent
     2674      <p id="rfc.section.10.1.p.19"> <b>Note:</b> A user agent might be provided with a default set of quality values for certain media ranges. However, unless the user agent
    26762675         is a closed system which cannot interact with other rendering agents, this default set ought to be configurable by the user.
    26772676      </p>
    26782677      <div id="rfc.iref.a.2"></div>
    26792678      <div id="rfc.iref.h.3"></div>
    2680       <h2 id="rfc.section.11.2"><a href="#rfc.section.11.2">11.2</a>&nbsp;<a id="header.accept-charset" href="#header.accept-charset">Accept-Charset</a></h2>
    2681       <p id="rfc.section.11.2.p.1">The "Accept-Charset" header field can be used by user agents to indicate what character encodings are acceptable in a response
     2679      <h2 id="rfc.section.10.2"><a href="#rfc.section.10.2">10.2</a>&nbsp;<a id="header.accept-charset" href="#header.accept-charset">Accept-Charset</a></h2>
     2680      <p id="rfc.section.10.2.p.1">The "Accept-Charset" header field can be used by user agents to indicate what character encodings are acceptable in a response
    26822681         payload. This field allows clients capable of understanding more comprehensive or special-purpose character encodings to signal
    26832682         that capability to a server which is capable of representing documents in those character encodings.
    26842683      </p>
    26852684      <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.37"></span>  <a href="#header.accept-charset" class="smpl">Accept-Charset</a> = 1#( ( <a href="#rule.charset" class="smpl">charset</a> / "*" ) [ <a href="#quality.values" class="smpl">weight</a> ] )
    2686 </pre><p id="rfc.section.11.2.p.3">Character encoding values (a.k.a., charsets) are described in <a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;8.3</a>. Each charset <em class="bcp14">MAY</em> be given an associated quality value which represents the user's preference for that charset, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;10.3</a>. An example is
     2685</pre><p id="rfc.section.10.2.p.3">Character encoding values (a.k.a., charsets) are described in <a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;8.3</a>. Each charset <em class="bcp14">MAY</em> be given an associated quality value which represents the user's preference for that charset, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;3.4.3</a>. An example is
    26872686      </p>
    26882687      <div id="rfc.figure.u.28"></div><pre class="text">  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
    2689 </pre><p id="rfc.section.11.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding which is not mentioned elsewhere
     2688</pre><p id="rfc.section.10.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding which is not mentioned elsewhere
    26902689         in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then any character encodings not explicitly
    26912690         mentioned in the field are considered "not acceptable" to the client.
    26922691      </p>
    2693       <p id="rfc.section.11.2.p.6">A request without any Accept-Charset header field implies that the user agent will accept any character encoding in response.</p>
    2694       <p id="rfc.section.11.2.p.7">If an Accept-Charset header field is present in a request and none of the available representations for the response have
     2692      <p id="rfc.section.10.2.p.6">A request without any Accept-Charset header field implies that the user agent will accept any character encoding in response.</p>
     2693      <p id="rfc.section.10.2.p.7">If an Accept-Charset header field is present in a request and none of the available representations for the response have
    26952694         a character encoding that is listed as acceptable, the origin server <em class="bcp14">MAY</em> either honor the Accept-Charset header field by sending a <a href="#status.406" class="smpl">406 (Not Acceptable)</a> response or disregard the Accept-Charset header field by treating the response as if it is not subject to content negotiation.
    26962695      </p>
    26972696      <div id="rfc.iref.a.3"></div>
    26982697      <div id="rfc.iref.h.4"></div>
    2699       <h2 id="rfc.section.11.3"><a href="#rfc.section.11.3">11.3</a>&nbsp;<a id="header.accept-encoding" href="#header.accept-encoding">Accept-Encoding</a></h2>
    2700       <p id="rfc.section.11.3.p.1">The "Accept-Encoding" header field can be used by user agents to indicate what response content-codings (<a href="#content.codings" title="Content Codings">Section&nbsp;8.4</a>) are acceptable in the response. An "identity" token is used as a synonym for "no encoding" in order to communicate when
     2698      <h2 id="rfc.section.10.3"><a href="#rfc.section.10.3">10.3</a>&nbsp;<a id="header.accept-encoding" href="#header.accept-encoding">Accept-Encoding</a></h2>
     2699      <p id="rfc.section.10.3.p.1">The "Accept-Encoding" header field can be used by user agents to indicate what response content-codings (<a href="#content.codings" title="Content Codings">Section&nbsp;8.4</a>) are acceptable in the response. An "identity" token is used as a synonym for "no encoding" in order to communicate when
    27012700         no encoding is preferred.
    27022701      </p>
    27032702      <div id="rfc.figure.u.29"></div><pre class="inline"><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></span>  <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a>  = #( <a href="#header.accept-encoding" class="smpl">codings</a> [ <a href="#quality.values" class="smpl">weight</a> ] )
    27042703  <a href="#header.accept-encoding" class="smpl">codings</a>          = <a href="#content.codings" class="smpl">content-coding</a> / "identity" / "*"
    2705 </pre><p id="rfc.section.11.3.p.3">Each codings value <em class="bcp14">MAY</em> be given an associated quality value which represents the preference for that encoding, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;10.3</a>.
    2706       </p>
    2707       <p id="rfc.section.11.3.p.4">For example,</p>
     2704</pre><p id="rfc.section.10.3.p.3">Each codings value <em class="bcp14">MAY</em> be given an associated quality value which represents the preference for that encoding, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;3.4.3</a>.
     2705      </p>
     2706      <p id="rfc.section.10.3.p.4">For example,</p>
    27082707      <div id="rfc.figure.u.30"></div><pre class="text">  Accept-Encoding: compress, gzip
    27092708  Accept-Encoding:
    … …  
    27112710  Accept-Encoding: compress;q=0.5, gzip;q=1.0
    27122711  Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
    2713 </pre><p id="rfc.section.11.3.p.6">A server tests whether a content-coding for a given representation is acceptable, according to an Accept-Encoding field, using
     2712</pre><p id="rfc.section.10.3.p.6">A server tests whether a content-coding for a given representation is acceptable, according to an Accept-Encoding field, using
    27142713         these rules:
    27152714      </p>
    … …  
    27222721         </li>
    27232722         <li>If the representation's content-coding is one of the content-codings listed in the Accept-Encoding field, then it is acceptable
    2724             unless it is accompanied by a qvalue of 0. (As defined in <a href="#quality.values" title="Quality Values">Section&nbsp;10.3</a>, a qvalue of 0 means "not acceptable".)
     2723            unless it is accompanied by a qvalue of 0. (As defined in <a href="#quality.values" title="Quality Values">Section&nbsp;3.4.3</a>, a qvalue of 0 means "not acceptable".)
    27252724         </li>
    27262725         <li>If multiple content-codings are acceptable, then the acceptable content-coding with the highest non-zero qvalue is preferred.</li>
    27272726      </ol>
    2728       <p id="rfc.section.11.3.p.7">An Accept-Encoding header field with a combined field-value that is empty implies that the user agent does not want any content-coding
     2727      <p id="rfc.section.10.3.p.7">An Accept-Encoding header field with a combined field-value that is empty implies that the user agent does not want any content-coding
    27292728         in response. If an Accept-Encoding header field is present in a request and none of the available representations for the
    27302729         response have a content-coding that is listed as acceptable, the origin server <em class="bcp14">SHOULD</em> send a response without any content-coding.
    27312730      </p>
    2732       <p id="rfc.section.11.3.p.8">A request without an Accept-Encoding header field implies that the user agent will accept any content-coding in response.</p>
    2733       <div class="note" id="rfc.section.11.3.p.9">
     2731      <p id="rfc.section.10.3.p.8">A request without an Accept-Encoding header field implies that the user agent will accept any content-coding in response.</p>
     2732      <div class="note" id="rfc.section.10.3.p.9">
    27342733         <p> <b>Note:</b> Most HTTP/1.0 applications do not recognize or obey qvalues associated with content-codings. This means that qvalues will
    27352734            not work and are not permitted with x-gzip or x-compress.
    … …  
    27382737      <div id="rfc.iref.a.4"></div>
    27392738      <div id="rfc.iref.h.5"></div>
    2740       <h2 id="rfc.section.11.4"><a href="#rfc.section.11.4">11.4</a>&nbsp;<a id="header.accept-language" href="#header.accept-language">Accept-Language</a></h2>
    2741       <p id="rfc.section.11.4.p.1">The "Accept-Language" header field can be used by user agents to indicate the set of natural languages that are preferred
     2739      <h2 id="rfc.section.10.4"><a href="#rfc.section.10.4">10.4</a>&nbsp;<a id="header.accept-language" href="#header.accept-language">Accept-Language</a></h2>
     2740      <p id="rfc.section.10.4.p.1">The "Accept-Language" header field can be used by user agents to indicate the set of natural languages that are preferred
    27422741         in the response. Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;8.6</a>.
    27432742      </p>
    … …  
    27452744  <a href="#header.accept-language" class="smpl">language-range</a>  =
    27462745            &lt;language-range, defined in <a href="#RFC4647" id="rfc.xref.RFC4647.1"><cite title="Matching of Language Tags">[RFC4647]</cite></a>, <a href="http://tools.ietf.org/html/rfc4647#section-2.1">Section 2.1</a>&gt;
    2747 </pre><p id="rfc.section.11.4.p.3">Each language-range can be given an associated quality value which represents an estimate of the user's preference for the
    2748          languages specified by that range, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;10.3</a>. For example,
     2746</pre><p id="rfc.section.10.4.p.3">Each language-range can be given an associated quality value which represents an estimate of the user's preference for the
     2747         languages specified by that range, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;3.4.3</a>. For example,
    27492748      </p>
    27502749      <div id="rfc.figure.u.32"></div><pre class="text">  Accept-Language: da, en-gb;q=0.8, en;q=0.7
    2751 </pre><p id="rfc.section.11.4.p.5">would mean: "I prefer Danish, but will accept British English and other types of English". (see also <a href="http://tools.ietf.org/html/rfc4647#section-2.3">Section 2.3</a> of <a href="#RFC4647" id="rfc.xref.RFC4647.2"><cite title="Matching of Language Tags">[RFC4647]</cite></a>)
    2752       </p>
    2753       <p id="rfc.section.11.4.p.6">For matching, <a href="http://tools.ietf.org/html/rfc4647#section-3">Section 3</a> of <a href="#RFC4647" id="rfc.xref.RFC4647.3"><cite title="Matching of Language Tags">[RFC4647]</cite></a> defines several matching schemes. Implementations can offer the most appropriate matching scheme for their requirements.
    2754       </p>
    2755       <div class="note" id="rfc.section.11.4.p.7">
     2750</pre><p id="rfc.section.10.4.p.5">would mean: "I prefer Danish, but will accept British English and other types of English". (see also <a href="http://tools.ietf.org/html/rfc4647#section-2.3">Section 2.3</a> of <a href="#RFC4647" id="rfc.xref.RFC4647.2"><cite title="Matching of Language Tags">[RFC4647]</cite></a>)
     2751      </p>
     2752      <p id="rfc.section.10.4.p.6">For matching, <a href="http://tools.ietf.org/html/rfc4647#section-3">Section 3</a> of <a href="#RFC4647" id="rfc.xref.RFC4647.3"><cite title="Matching of Language Tags">[RFC4647]</cite></a> defines several matching schemes. Implementations can offer the most appropriate matching scheme for their requirements.
     2753      </p>
     2754      <div class="note" id="rfc.section.10.4.p.7">
    27562755         <p> <b>Note:</b> The "Basic Filtering" scheme (<a href="#RFC4647" id="rfc.xref.RFC4647.4"><cite title="Matching of Language Tags">[RFC4647]</cite></a>, <a href="http://tools.ietf.org/html/rfc4647#section-3.3.1">Section 3.3.1</a>) is identical to the matching scheme that was previously defined in <a href="http://tools.ietf.org/html/rfc2616#section-14.4">Section 14.4</a> of <a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
    27572756         </p>
    27582757      </div>
    2759       <p id="rfc.section.11.4.p.8">It might be contrary to the privacy expectations of the user to send an Accept-Language header field with the complete linguistic
    2760          preferences of the user in every request. For a discussion of this issue, see <a href="#privacy.issues.connected.to.accept.header.fields" title="Privacy Issues Connected to Accept Header Fields">Section&nbsp;13.5</a>.
    2761       </p>
    2762       <p id="rfc.section.11.4.p.9">As intelligibility is highly dependent on the individual user, it is recommended that client applications make the choice
     2758      <p id="rfc.section.10.4.p.8">It might be contrary to the privacy expectations of the user to send an Accept-Language header field with the complete linguistic
     2759         preferences of the user in every request. For a discussion of this issue, see <a href="#privacy.issues.connected.to.accept.header.fields" title="Privacy Issues Connected to Accept Header Fields">Section&nbsp;12.5</a>.
     2760      </p>
     2761      <p id="rfc.section.10.4.p.9">As intelligibility is highly dependent on the individual user, it is recommended that client applications make the choice
    27632762         of linguistic preference available to the user. If the choice is not made available, then the Accept-Language header field <em class="bcp14">MUST NOT</em> be given in the request.
    27642763      </p>
    2765       <div class="note" id="rfc.section.11.4.p.10">
     2764      <div class="note" id="rfc.section.10.4.p.10">
    27662765         <p> <b>Note:</b> When making the choice of linguistic preference available to the user, we remind implementers of the fact that users are not
    27672766            familiar with the details of language matching as described above, and ought to be provided appropriate guidance. As an example,
    … …  
    27722771      <div id="rfc.iref.a.5"></div>
    27732772      <div id="rfc.iref.h.6"></div>
    2774       <h2 id="rfc.section.11.5"><a href="#rfc.section.11.5">11.5</a>&nbsp;<a id="header.allow" href="#header.allow">Allow</a></h2>
    2775       <p id="rfc.section.11.5.p.1">The "Allow" header field lists the set of methods advertised as supported by the target resource. The purpose of this field
     2773      <h2 id="rfc.section.10.5"><a href="#rfc.section.10.5">10.5</a>&nbsp;<a id="header.allow" href="#header.allow">Allow</a></h2>
     2774      <p id="rfc.section.10.5.p.1">The "Allow" header field lists the set of methods advertised as supported by the target resource. The purpose of this field
    27762775         is strictly to inform the recipient of valid request methods associated with the resource.
    27772776      </p>
    27782777      <div id="rfc.figure.u.33"></div><pre class="inline"><span id="rfc.iref.g.42"></span>  <a href="#header.allow" class="smpl">Allow</a> = #<a href="#method.overview" class="smpl">method</a>
    2779 </pre><p id="rfc.section.11.5.p.3">Example of use:</p>
     2778</pre><p id="rfc.section.10.5.p.3">Example of use:</p>
    27802779      <div id="rfc.figure.u.34"></div><pre class="text">  Allow: GET, HEAD, PUT
    2781 </pre><p id="rfc.section.11.5.p.5">The actual set of allowed methods is defined by the origin server at the time of each request.</p>
    2782       <p id="rfc.section.11.5.p.6">A proxy <em class="bcp14">MUST NOT</em> modify the Allow header field — it does not need to understand all the methods specified in order to handle them according
     2780</pre><p id="rfc.section.10.5.p.5">The actual set of allowed methods is defined by the origin server at the time of each request.</p>
     2781      <p id="rfc.section.10.5.p.6">A proxy <em class="bcp14">MUST NOT</em> modify the Allow header field — it does not need to understand all the methods specified in order to handle them according
    27832782         to the generic message handling rules.
    27842783      </p>
    27852784      <div id="rfc.iref.c.8"></div>
    27862785      <div id="rfc.iref.h.7"></div>
    2787       <h2 id="rfc.section.11.6"><a href="#rfc.section.11.6">11.6</a>&nbsp;<a id="header.content-encoding" href="#header.content-encoding">Content-Encoding</a></h2>
    2788       <p id="rfc.section.11.6.p.1">The "Content-Encoding" header field indicates what content-codings have been applied to the representation beyond those inherent
     2786      <h2 id="rfc.section.10.6"><a href="#rfc.section.10.6">10.6</a>&nbsp;<a id="header.content-encoding" href="#header.content-encoding">Content-Encoding</a></h2>
     2787      <p id="rfc.section.10.6.p.1">The "Content-Encoding" header field indicates what content-codings have been applied to the representation beyond those inherent
    27892788         in the media type, and thus what decoding mechanisms have to be applied in order to obtain the media-type referenced by the <a href="#header.content-type" class="smpl">Content-Type</a> header field. Content-Encoding is primarily used to allow a representation to be compressed without losing the identity of
    27902789         its underlying media type.
    27912790      </p>
    27922791      <div id="rfc.figure.u.35"></div><pre class="inline"><span id="rfc.iref.g.43"></span>  <a href="#header.content-encoding" class="smpl">Content-Encoding</a> = 1#<a href="#content.codings" class="smpl">content-coding</a>
    2793 </pre><p id="rfc.section.11.6.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Section&nbsp;8.4</a>. An example of its use is
     2792</pre><p id="rfc.section.10.6.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Section&nbsp;8.4</a>. An example of its use is
    27942793      </p>
    27952794      <div id="rfc.figure.u.36"></div><pre class="text">  Content-Encoding: gzip
    2796 </pre><p id="rfc.section.11.6.p.5">The content-coding is a characteristic of the representation. Typically, the representation body is stored with this encoding
     2795</pre><p id="rfc.section.10.6.p.5">The content-coding is a characteristic of the representation. Typically, the representation body is stored with this encoding
    27972796         and is only decoded before rendering or analogous usage. However, a transforming proxy <em class="bcp14">MAY</em> modify the content-coding if the new coding is known to be acceptable to the recipient, unless the "no-transform" cache-control
    27982797         directive is present in the message.
    27992798      </p>
    2800       <p id="rfc.section.11.6.p.6">If the media type includes an inherent encoding, such as a data format that is always compressed, then that encoding would
     2799      <p id="rfc.section.10.6.p.6">If the media type includes an inherent encoding, such as a data format that is always compressed, then that encoding would
    28012800         not be restated as a Content-Encoding even if it happens to be the same algorithm as one of the content-codings. Such a content-coding
    28022801         would only be listed if, for some bizarre reason, it is applied a second time to form the representation. Likewise, an origin
    … …  
    28052804         as ..." dialog instead of automatic decompression and rendering of content).
    28062805      </p>
    2807       <p id="rfc.section.11.6.p.7">A representation that has a content-coding applied to it <em class="bcp14">MUST</em> include a Content-Encoding header field that lists the content-coding(s) applied.
    2808       </p>
    2809       <p id="rfc.section.11.6.p.8">If multiple encodings have been applied to a representation, the content codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other header fields not defined by this specification.
    2810       </p>
    2811       <p id="rfc.section.11.6.p.9">If the content-coding of a representation in a request message is not acceptable to the origin server, the server <em class="bcp14">SHOULD</em> respond with a status code of 415 (Unsupported Media Type).
     2806      <p id="rfc.section.10.6.p.7">A representation that has a content-coding applied to it <em class="bcp14">MUST</em> include a Content-Encoding header field that lists the content-coding(s) applied.
     2807      </p>
     2808      <p id="rfc.section.10.6.p.8">If multiple encodings have been applied to a representation, the content codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other header fields not defined by this specification.
     2809      </p>
     2810      <p id="rfc.section.10.6.p.9">If the content-coding of a representation in a request message is not acceptable to the origin server, the server <em class="bcp14">SHOULD</em> respond with a status code of 415 (Unsupported Media Type).
    28122811      </p>
    28132812      <div id="rfc.iref.c.9"></div>
    28142813      <div id="rfc.iref.h.8"></div>
    2815       <h2 id="rfc.section.11.7"><a href="#rfc.section.11.7">11.7</a>&nbsp;<a id="header.content-language" href="#header.content-language">Content-Language</a></h2>
    2816       <p id="rfc.section.11.7.p.1">The "Content-Language" header field describes the natural language(s) of the intended audience for the representation. Note
     2814      <h2 id="rfc.section.10.7"><a href="#rfc.section.10.7">10.7</a>&nbsp;<a id="header.content-language" href="#header.content-language">Content-Language</a></h2>
     2815      <p id="rfc.section.10.7.p.1">The "Content-Language" header field describes the natural language(s) of the intended audience for the representation. Note
    28172816         that this might not be equivalent to all the languages used within the representation.
    28182817      </p>
    28192818      <div id="rfc.figure.u.37"></div><pre class="inline"><span id="rfc.iref.g.44"></span>  <a href="#header.content-language" class="smpl">Content-Language</a> = 1#<a href="#language.tags" class="smpl">language-tag</a>
    2820 </pre><p id="rfc.section.11.7.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;8.6</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate representations according to the
     2819</pre><p id="rfc.section.10.7.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;8.6</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate representations according to the
    28212820         user's own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate
    28222821         field is
    28232822      </p>
    28242823      <div id="rfc.figure.u.38"></div><pre class="text">  Content-Language: da
    2825 </pre><p id="rfc.section.11.7.p.5">If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean
     2824</pre><p id="rfc.section.10.7.p.5">If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean
    28262825         that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language
    28272826         it is intended.
    28282827      </p>
    2829       <p id="rfc.section.11.7.p.6">Multiple languages <em class="bcp14">MAY</em> be listed for content that is intended for multiple audiences. For example, a rendition of the "Treaty of Waitangi", presented
     2828      <p id="rfc.section.10.7.p.6">Multiple languages <em class="bcp14">MAY</em> be listed for content that is intended for multiple audiences. For example, a rendition of the "Treaty of Waitangi", presented
    28302829         simultaneously in the original Maori and English versions, would call for
    28312830      </p>
    28322831      <div id="rfc.figure.u.39"></div><pre class="text">  Content-Language: mi, en
    2833 </pre><p id="rfc.section.11.7.p.8">However, just because multiple languages are present within a representation does not mean that it is intended for multiple
     2832</pre><p id="rfc.section.10.7.p.8">However, just because multiple languages are present within a representation does not mean that it is intended for multiple
    28342833         linguistic audiences. An example would be a beginner's language primer, such as "A First Lesson in Latin", which is clearly
    28352834         intended to be used by an English-literate audience. In this case, the Content-Language would properly only include "en".
    28362835      </p>
    2837       <p id="rfc.section.11.7.p.9">Content-Language <em class="bcp14">MAY</em> be applied to any media type — it is not limited to textual documents.
     2836      <p id="rfc.section.10.7.p.9">Content-Language <em class="bcp14">MAY</em> be applied to any media type — it is not limited to textual documents.
    28382837      </p>
    28392838      <div id="rfc.iref.c.10"></div>
    28402839      <div id="rfc.iref.h.9"></div>
    2841       <h2 id="rfc.section.11.8"><a href="#rfc.section.11.8">11.8</a>&nbsp;<a id="header.content-location" href="#header.content-location">Content-Location</a></h2>
    2842       <p id="rfc.section.11.8.p.1">The "Content-Location" header field supplies a URI that can be used as a specific identifier for the representation in this
     2840      <h2 id="rfc.section.10.8"><a href="#rfc.section.10.8">10.8</a>&nbsp;<a id="header.content-location" href="#header.content-location">Content-Location</a></h2>
     2841      <p id="rfc.section.10.8.p.1">The "Content-Location" header field supplies a URI that can be used as a specific identifier for the representation in this
    28432842         message. In other words, if one were to perform a GET on this URI at the time of this message's generation, then a <a href="#status.200" class="smpl">200 (OK)</a> response would contain the same representation that is enclosed as payload in this message.
    28442843      </p>
    28452844      <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.45"></span>  <a href="#header.content-location" class="smpl">Content-Location</a> = <a href="#imported.abnf" class="smpl">absolute-URI</a> / <a href="#imported.abnf" class="smpl">partial-URI</a>
    2846 </pre><p id="rfc.section.11.8.p.3">The Content-Location value is not a replacement for the effective Request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.27"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>). It is representation metadata. It has the same syntax and semantics as the header field of the same name defined for MIME
     2845</pre><p id="rfc.section.10.8.p.3">The Content-Location value is not a replacement for the effective Request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.27"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>). It is representation metadata. It has the same syntax and semantics as the header field of the same name defined for MIME
    28472846         body parts in <a href="http://tools.ietf.org/html/rfc2557#section-4">Section 4</a> of <a href="#RFC2557" id="rfc.xref.RFC2557.1"><cite title="MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)">[RFC2557]</cite></a>. However, its appearance in an HTTP message has some special implications for HTTP recipients.
    28482847      </p>
    2849       <p id="rfc.section.11.8.p.4">If Content-Location is included in a response message and its value is the same as the effective request URI, then the response
     2848      <p id="rfc.section.10.8.p.4">If Content-Location is included in a response message and its value is the same as the effective request URI, then the response
    28502849         payload <em class="bcp14">SHOULD</em> be considered a current representation of that resource. For a GET or HEAD request, this is the same as the default semantics
    28512850         when no Content-Location is provided by the server. For a state-changing request like PUT or POST, it implies that the server's
    … …  
    28542853         need for a subsequent GET request.
    28552854      </p>
    2856       <p id="rfc.section.11.8.p.5">If Content-Location is included in a response message and its value differs from the effective request URI, then the origin
     2855      <p id="rfc.section.10.8.p.5">If Content-Location is included in a response message and its value differs from the effective request URI, then the origin
    28572856         server is informing recipients that this representation has its own, presumably more specific, identifier. For a GET or HEAD
    28582857         request, this is an indication that the effective request URI identifies a resource that is subject to content negotiation
    … …  
    28622861         the payload of the <a href="#status.200" class="smpl">200 (OK)</a> response; the Content-Location value provides an identifier for retrieving a copy of that same receipt in the future.
    28632862      </p>
    2864       <p id="rfc.section.11.8.p.6">If Content-Location is included in a request message, then it <em class="bcp14">MAY</em> be interpreted by the origin server as an indication of where the user agent originally obtained the content of the enclosed
     2863      <p id="rfc.section.10.8.p.6">If Content-Location is included in a request message, then it <em class="bcp14">MAY</em> be interpreted by the origin server as an indication of where the user agent originally obtained the content of the enclosed
    28652864         representation (prior to any subsequent modification of the content by that user agent). In other words, the user agent is
    28662865         providing the same representation metadata that it received with the original representation. However, such interpretation <em class="bcp14">MUST NOT</em> be used to alter the semantics of the method requested by the client. For example, if a client makes a PUT request on a negotiated
    … …  
    28702869         latter semantics, it would have applied the PUT directly to the Content-Location URI.
    28712870      </p>
    2872       <p id="rfc.section.11.8.p.7">A Content-Location field received in a request message is transitory information that <em class="bcp14">SHOULD NOT</em> be saved with other representation metadata for use in later responses. The Content-Location's value might be saved for use
     2871      <p id="rfc.section.10.8.p.7">A Content-Location field received in a request message is transitory information that <em class="bcp14">SHOULD NOT</em> be saved with other representation metadata for use in later responses. The Content-Location's value might be saved for use
    28732872         in other contexts, such as within source links or other metadata.
    28742873      </p>
    2875       <p id="rfc.section.11.8.p.8">A cache cannot assume that a representation with a Content-Location different from the URI used to retrieve it can be used
     2874      <p id="rfc.section.10.8.p.8">A cache cannot assume that a representation with a Content-Location different from the URI used to retrieve it can be used
    28762875         to respond to later requests on that Content-Location URI.
    28772876      </p>
    2878       <p id="rfc.section.11.8.p.9">If the Content-Location value is a partial URI, the partial URI is interpreted relative to the effective request URI.</p>
     2877      <p id="rfc.section.10.8.p.9">If the Content-Location value is a partial URI, the partial URI is interpreted relative to the effective request URI.</p>
    28792878      <div id="rfc.iref.c.11"></div>
    28802879      <div id="rfc.iref.h.10"></div>
    2881       <h2 id="rfc.section.11.9"><a href="#rfc.section.11.9">11.9</a>&nbsp;<a id="header.content-type" href="#header.content-type">Content-Type</a></h2>
    2882       <p id="rfc.section.11.9.p.1">The "Content-Type" header field indicates the media type of the representation. In the case of responses to the HEAD method,
     2880      <h2 id="rfc.section.10.9"><a href="#rfc.section.10.9">10.9</a>&nbsp;<a id="header.content-type" href="#header.content-type">Content-Type</a></h2>
     2881      <p id="rfc.section.10.9.p.1">The "Content-Type" header field indicates the media type of the representation. In the case of responses to the HEAD method,
    28832882         the media type is that which would have been sent had the request been a GET.
    28842883      </p>
    28852884      <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.46"></span>  <a href="#header.content-type" class="smpl">Content-Type</a> = <a href="#media.types" class="smpl">media-type</a>
    2886 </pre><p id="rfc.section.11.9.p.3">Media types are defined in <a href="#media.types" title="Media Types">Section&nbsp;8.5</a>. An example of the field is
     2885</pre><p id="rfc.section.10.9.p.3">Media types are defined in <a href="#media.types" title="Media Types">Section&nbsp;8.5</a>. An example of the field is
    28872886      </p>
    28882887      <div id="rfc.figure.u.42"></div><pre class="text">  Content-Type: text/html; charset=ISO-8859-4
    2889 </pre><p id="rfc.section.11.9.p.5">Further discussion of Content-Type is provided in <a href="#representation.data" title="Representation Data">Section&nbsp;3.3</a>.
     2888</pre><p id="rfc.section.10.9.p.5">Further discussion of Content-Type is provided in <a href="#representation.data" title="Representation Data">Section&nbsp;3.3</a>.
    28902889      </p>
    28912890      <div id="rfc.iref.d.3"></div>
    28922891      <div id="rfc.iref.h.11"></div>
    2893       <h2 id="rfc.section.11.10"><a href="#rfc.section.11.10">11.10</a>&nbsp;<a id="header.date" href="#header.date">Date</a></h2>
    2894       <p id="rfc.section.11.10.p.1">The "Date" header field represents the date and time at which the message was originated, having the same semantics as the
     2892      <h2 id="rfc.section.10.10"><a href="#rfc.section.10.10">10.10</a>&nbsp;<a id="header.date" href="#header.date">Date</a></h2>
     2893      <p id="rfc.section.10.10.p.1">The "Date" header field represents the date and time at which the message was originated, having the same semantics as the
    28952894         Origination Date Field (orig-date) defined in <a href="http://tools.ietf.org/html/rfc5322#section-3.6.1">Section 3.6.1</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as defined in <a href="#http.date" title="Date/Time Formats">Section&nbsp;8.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.
    28962895      </p>
    28972896      <div id="rfc.figure.u.43"></div><pre class="inline"><span id="rfc.iref.g.47"></span>  <a href="#header.date" class="smpl">Date</a> = <a href="#http.date" class="smpl">HTTP-date</a>
    2898 </pre><p id="rfc.section.11.10.p.3">An example is</p>
     2897</pre><p id="rfc.section.10.10.p.3">An example is</p>
    28992898      <div id="rfc.figure.u.44"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
    2900 </pre><p id="rfc.section.11.10.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
     2899</pre><p id="rfc.section.10.10.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
    29012900      </p>
    29022901      <ol>
    … …  
    29092908         </li>
    29102909      </ol>
    2911       <p id="rfc.section.11.10.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient.
    2912       </p>
    2913       <p id="rfc.section.11.10.p.7">Clients can use the Date header field as well; in order to keep request messages small, they are advised not to include it
     2910      <p id="rfc.section.10.10.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient.
     2911      </p>
     2912      <p id="rfc.section.10.10.p.7">Clients can use the Date header field as well; in order to keep request messages small, they are advised not to include it
    29142913         when it doesn't convey any useful information (as is usually the case for requests that do not contain a payload).
    29152914      </p>
    2916       <p id="rfc.section.11.10.p.8">The HTTP-date sent in a Date header field <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means
     2915      <p id="rfc.section.10.10.p.8">The HTTP-date sent in a Date header field <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means
    29172916         of generating a reasonably accurate date and time. In theory, the date ought to represent the moment just before the payload
    29182917         is generated. In practice, the date can be generated at any time during the message origination without affecting its semantic
    … …  
    29212920      <div id="rfc.iref.e.1"></div>
    29222921      <div id="rfc.iref.h.12"></div>
    2923       <h2 id="rfc.section.11.11"><a href="#rfc.section.11.11">11.11</a>&nbsp;<a id="header.expect" href="#header.expect">Expect</a></h2>
    2924       <p id="rfc.section.11.11.p.1">The "Expect" header field is used to indicate that particular server behaviors are required by the client.</p>
     2922      <h2 id="rfc.section.10.11"><a href="#rfc.section.10.11">10.11</a>&nbsp;<a id="header.expect" href="#header.expect">Expect</a></h2>
     2923      <p id="rfc.section.10.11.p.1">The "Expect" header field is used to indicate that particular server behaviors are required by the client.</p>
    29252924      <div id="rfc.figure.u.45"></div><pre class="inline"><span id="rfc.iref.g.48"></span><span id="rfc.iref.g.49"></span><span id="rfc.iref.g.50"></span><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span>  <a href="#header.expect" class="smpl">Expect</a>       = 1#<a href="#header.expect" class="smpl">expectation</a>
    29262925 
    … …  
    29312930  <a href="#header.expect" class="smpl">expect-name</a>  = <a href="#imported.abnf" class="smpl">token</a>
    29322931  <a href="#header.expect" class="smpl">expect-value</a> = <a href="#imported.abnf" class="smpl">token</a> / <a href="#imported.abnf" class="smpl">quoted-string</a>
    2933 </pre><p id="rfc.section.11.11.p.3">If all received Expect header field(s) are syntactically valid but contain an expectation that the recipient does not understand
     2932</pre><p id="rfc.section.10.11.p.3">If all received Expect header field(s) are syntactically valid but contain an expectation that the recipient does not understand
    29342933         or cannot comply with, the recipient <em class="bcp14">MUST</em> respond with a <a href="#status.417" class="smpl">417 (Expectation Failed)</a> status code. A recipient of a syntactically invalid Expectation header field <em class="bcp14">MUST</em> respond with a <a href="#status.4xx" class="smpl">4xx</a> status code other than 417.
    29352934      </p>
    2936       <p id="rfc.section.11.11.p.4">The only expectation defined by this specification is:</p>
    2937       <p id="rfc.section.11.11.p.5"><span id="rfc.iref.142"></span><span id="rfc.iref.e.2"></span> 100-continue
     2935      <p id="rfc.section.10.11.p.4">The only expectation defined by this specification is:</p>
     2936      <p id="rfc.section.10.11.p.5"><span id="rfc.iref.142"></span><span id="rfc.iref.e.2"></span> 100-continue
    29382937      </p>
    29392938      <ul class="empty">
    … …  
    29412940         </li>
    29422941      </ul>
    2943       <p id="rfc.section.11.11.p.6">Comparison is case-insensitive for names (expect-name), and case-sensitive for values (expect-value).</p>
    2944       <p id="rfc.section.11.11.p.7">The Expect mechanism is hop-by-hop: the above requirements apply to any server, including proxies. However, the Expect header
     2942      <p id="rfc.section.10.11.p.6">Comparison is case-insensitive for names (expect-name), and case-sensitive for values (expect-value).</p>
     2943      <p id="rfc.section.10.11.p.7">The Expect mechanism is hop-by-hop: the above requirements apply to any server, including proxies. However, the Expect header
    29452944         field itself is end-to-end; it <em class="bcp14">MUST</em> be forwarded if the request is forwarded.
    29462945      </p>
    2947       <p id="rfc.section.11.11.p.8">Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header field.</p>
     2946      <p id="rfc.section.10.11.p.8">Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header field.</p>
    29482947      <div id="rfc.iref.f.1"></div>
    29492948      <div id="rfc.iref.h.13"></div>
    2950       <h2 id="rfc.section.11.12"><a href="#rfc.section.11.12">11.12</a>&nbsp;<a id="header.from" href="#header.from">From</a></h2>
    2951       <p id="rfc.section.11.12.p.1">The "From" header field, if given, <em class="bcp14">SHOULD</em> contain an Internet e-mail address for the human user who controls the requesting user agent. The address <em class="bcp14">SHOULD</em> be machine-usable, as defined by "mailbox" in <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>:
     2949      <h2 id="rfc.section.10.12"><a href="#rfc.section.10.12">10.12</a>&nbsp;<a id="header.from" href="#header.from">From</a></h2>
     2950      <p id="rfc.section.10.12.p.1">The "From" header field, if given, <em class="bcp14">SHOULD</em> contain an Internet e-mail address for the human user who controls the requesting user agent. The address <em class="bcp14">SHOULD</em> be machine-usable, as defined by "mailbox" in <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>:
    29522951      </p>
    29532952      <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.53"></span>  <a href="#header.from" class="smpl">From</a>    = <a href="#header.from" class="smpl">mailbox</a>
    29542953 
    29552954  <a href="#header.from" class="smpl">mailbox</a> = &lt;mailbox, defined in <a href="#RFC5322" id="rfc.xref.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a>&gt;
    2956 </pre><p id="rfc.section.11.12.p.3">An example is:</p>
     2955</pre><p id="rfc.section.10.12.p.3">An example is:</p>
    29572956      <div id="rfc.figure.u.47"></div><pre class="text">  From: webmaster@example.org
    2958 </pre><p id="rfc.section.11.12.p.5">This header field <em class="bcp14">MAY</em> be used for logging purposes and as a means for identifying the source of invalid or unwanted requests. It <em class="bcp14">SHOULD NOT</em> be used as an insecure form of access protection. The interpretation of this field is that the request is being performed
     2957</pre><p id="rfc.section.10.12.p.5">This header field <em class="bcp14">MAY</em> be used for logging purposes and as a means for identifying the source of invalid or unwanted requests. It <em class="bcp14">SHOULD NOT</em> be used as an insecure form of access protection. The interpretation of this field is that the request is being performed
    29592958         on behalf of the person given, who accepts responsibility for the method performed. In particular, robot agents <em class="bcp14">SHOULD</em> include this header field so that the person responsible for running the robot can be contacted if problems occur on the receiving
    29602959         end.
    29612960      </p>
    2962       <p id="rfc.section.11.12.p.6">The Internet e-mail address in this field <em class="bcp14">MAY</em> be separate from the Internet host which issued the request. For example, when a request is passed through a proxy the original
     2961      <p id="rfc.section.10.12.p.6">The Internet e-mail address in this field <em class="bcp14">MAY</em> be separate from the Internet host which issued the request. For example, when a request is passed through a proxy the original
    29632962         issuer's address <em class="bcp14">SHOULD</em> be used.
    29642963      </p>
    2965       <p id="rfc.section.11.12.p.7">The client <em class="bcp14">SHOULD NOT</em> send the From header field without the user's approval, as it might conflict with the user's privacy interests or their site's
     2964      <p id="rfc.section.10.12.p.7">The client <em class="bcp14">SHOULD NOT</em> send the From header field without the user's approval, as it might conflict with the user's privacy interests or their site's
    29662965         security policy. It is strongly recommended that the user be able to disable, enable, and modify the value of this field at
    29672966         any time prior to a request.
    … …  
    29692968      <div id="rfc.iref.l.1"></div>
    29702969      <div id="rfc.iref.h.14"></div>
    2971       <h2 id="rfc.section.11.13"><a href="#rfc.section.11.13">11.13</a>&nbsp;<a id="header.location" href="#header.location">Location</a></h2>
    2972       <p id="rfc.section.11.13.p.1">The "Location" header field <em class="bcp14">MAY</em> be sent in responses to refer to a specific resource in accordance with the semantics of the status code.
     2970      <h2 id="rfc.section.10.13"><a href="#rfc.section.10.13">10.13</a>&nbsp;<a id="header.location" href="#header.location">Location</a></h2>
     2971      <p id="rfc.section.10.13.p.1">The "Location" header field <em class="bcp14">MAY</em> be sent in responses to refer to a specific resource in accordance with the semantics of the status code.
    29732972      </p>
    29742973      <div id="rfc.figure.u.48"></div><pre class="inline"><span id="rfc.iref.g.54"></span>  <a href="#header.location" class="smpl">Location</a> = <a href="#imported.abnf" class="smpl">URI-reference</a>
    2975 </pre><p id="rfc.section.11.13.p.3">For <a href="#status.201" class="smpl">201 (Created)</a> responses, the Location is the URI of the new resource which was created by the request. For <a href="#status.3xx" class="smpl">3xx (Redirection)</a> responses, the location <em class="bcp14">SHOULD</em> indicate the server's preferred URI for automatic redirection to the resource.
    2976       </p>
    2977       <p id="rfc.section.11.13.p.4">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5</a>). If the original URI, as navigated to by the user agent, did contain a fragment identifier, and the final value does not,
     2974</pre><p id="rfc.section.10.13.p.3">For <a href="#status.201" class="smpl">201 (Created)</a> responses, the Location is the URI of the new resource which was created by the request. For <a href="#status.3xx" class="smpl">3xx (Redirection)</a> responses, the location <em class="bcp14">SHOULD</em> indicate the server's preferred URI for automatic redirection to the resource.
     2975      </p>
     2976      <p id="rfc.section.10.13.p.4">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5</a>). If the original URI, as navigated to by the user agent, did contain a fragment identifier, and the final value does not,
    29782977         then the original URI's fragment identifier is added to the final value.
    29792978      </p>
    … …  
    29842983      <p>An original URI "http://www.example.org/index.html#larry", combined with a field value given as:</p>  <pre class="text">  Location: http://www.example.net/index.html
    29852984</pre>  <p>would result in a final value of "http://www.example.net/index.html#larry", preserving the original fragment identifier.</p>
    2986       <div class="note" id="rfc.section.11.13.p.7">
     2985      <div class="note" id="rfc.section.10.13.p.7">
    29872986         <p> <b>Note:</b> Some recipients attempt to recover from Location fields that are not valid URI references. This specification does not mandate
    29882987            or define such processing, but does allow it.
    29892988         </p>
    29902989      </div>
    2991       <p id="rfc.section.11.13.p.8">There are circumstances in which a fragment identifier in a Location URI would not be appropriate. For instance, when it appears
     2990      <p id="rfc.section.10.13.p.8">There are circumstances in which a fragment identifier in a Location URI would not be appropriate. For instance, when it appears
    29922991         in a <a href="#status.201" class="smpl">201
    29932992            (Created)</a> response, where the Location header field specifies the URI for the entire created resource.
    29942993      </p>
    2995       <div class="note" id="rfc.section.11.13.p.9">
    2996          <p> <b>Note:</b> The <a href="#header.content-location" class="smpl">Content-Location</a> header field (<a href="#header.content-location" id="rfc.xref.header.content-location.3" title="Content-Location">Section&nbsp;11.8</a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation.
     2994      <div class="note" id="rfc.section.10.13.p.9">
     2995         <p> <b>Note:</b> The <a href="#header.content-location" class="smpl">Content-Location</a> header field (<a href="#header.content-location" id="rfc.xref.header.content-location.3" title="Content-Location">Section&nbsp;10.8</a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation.
    29972996            It is therefore possible for a response to contain header fields for both Location and Content-Location.
    29982997         </p>
    … …  
    30002999      <div id="rfc.iref.m.9"></div>
    30013000      <div id="rfc.iref.h.15"></div>
    3002       <h2 id="rfc.section.11.14"><a href="#rfc.section.11.14">11.14</a>&nbsp;<a id="header.max-forwards" href="#header.max-forwards">Max-Forwards</a></h2>
    3003       <p id="rfc.section.11.14.p.1">The "Max-Forwards" header field provides a mechanism with the TRACE (<a href="#TRACE" id="rfc.xref.TRACE.2" title="TRACE">Section&nbsp;4.3.8</a>) and OPTIONS (<a href="#OPTIONS" id="rfc.xref.OPTIONS.2" title="OPTIONS">Section&nbsp;4.3.7</a>) methods to limit the number of times that the request is forwarded by proxies. This can be useful when the client is attempting
     3001      <h2 id="rfc.section.10.14"><a href="#rfc.section.10.14">10.14</a>&nbsp;<a id="header.max-forwards" href="#header.max-forwards">Max-Forwards</a></h2>
     3002      <p id="rfc.section.10.14.p.1">The "Max-Forwards" header field provides a mechanism with the TRACE (<a href="#TRACE" id="rfc.xref.TRACE.2" title="TRACE">Section&nbsp;4.3.8</a>) and OPTIONS (<a href="#OPTIONS" id="rfc.xref.OPTIONS.2" title="OPTIONS">Section&nbsp;4.3.7</a>) methods to limit the number of times that the request is forwarded by proxies. This can be useful when the client is attempting
    30043003         to trace a request which appears to be failing or looping mid-chain.
    30053004      </p>
    30063005      <div id="rfc.figure.u.51"></div><pre class="inline"><span id="rfc.iref.g.55"></span>  <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*<a href="#imported.abnf" class="smpl">DIGIT</a>
    3007 </pre><p id="rfc.section.11.14.p.3">The Max-Forwards value is a decimal integer indicating the remaining number of times this request message can be forwarded.</p>
    3008       <p id="rfc.section.11.14.p.4">Each recipient of a TRACE or OPTIONS request containing a Max-Forwards header field <em class="bcp14">MUST</em> check and update its value prior to forwarding the request. If the received value is zero (0), the recipient <em class="bcp14">MUST NOT</em> forward the request; instead, it <em class="bcp14">MUST</em> respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message <em class="bcp14">MUST</em> contain an updated Max-Forwards field with a value decremented by one (1).
    3009       </p>
    3010       <p id="rfc.section.11.14.p.5">The Max-Forwards header field <em class="bcp14">MAY</em> be ignored for all other request methods.
     3006</pre><p id="rfc.section.10.14.p.3">The Max-Forwards value is a decimal integer indicating the remaining number of times this request message can be forwarded.</p>
     3007      <p id="rfc.section.10.14.p.4">Each recipient of a TRACE or OPTIONS request containing a Max-Forwards header field <em class="bcp14">MUST</em> check and update its value prior to forwarding the request. If the received value is zero (0), the recipient <em class="bcp14">MUST NOT</em> forward the request; instead, it <em class="bcp14">MUST</em> respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message <em class="bcp14">MUST</em> contain an updated Max-Forwards field with a value decremented by one (1).
     3008      </p>
     3009      <p id="rfc.section.10.14.p.5">The Max-Forwards header field <em class="bcp14">MAY</em> be ignored for all other request methods.
    30113010      </p>
    30123011      <div id="rfc.iref.r.2"></div>
    30133012      <div id="rfc.iref.h.16"></div>
    3014       <h2 id="rfc.section.11.15"><a href="#rfc.section.11.15">11.15</a>&nbsp;<a id="header.referer" href="#header.referer">Referer</a></h2>
    3015       <p id="rfc.section.11.15.p.1">The "Referer" [sic] header field allows the client to specify the URI of the resource from which the target URI was obtained
     3013      <h2 id="rfc.section.10.15"><a href="#rfc.section.10.15">10.15</a>&nbsp;<a id="header.referer" href="#header.referer">Referer</a></h2>
     3014      <p id="rfc.section.10.15.p.1">The "Referer" [sic] header field allows the client to specify the URI of the resource from which the target URI was obtained
    30163015         (the "referrer", although the header field is misspelled.).
    30173016      </p>
    3018       <p id="rfc.section.11.15.p.2">The Referer header field allows servers to generate lists of back-links to resources for interest, logging, optimized caching,
     3017      <p id="rfc.section.10.15.p.2">The Referer header field allows servers to generate lists of back-links to resources for interest, logging, optimized caching,
    30193018         etc. It also allows obsolete or mistyped links to be traced for maintenance. Some servers use Referer as a means of controlling
    30203019         where they allow links from (so-called "deep linking"), but legitimate requests do not always contain a Referer header field.
    30213020      </p>
    3022       <p id="rfc.section.11.15.p.3">If the target URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard), the Referer
     3021      <p id="rfc.section.10.15.p.3">If the target URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard), the Referer
    30233022         field <em class="bcp14">MUST</em> either be sent with the value "about:blank", or not be sent at all. Note that this requirement does not apply to sources with
    30243023         non-HTTP URIs (e.g., FTP).
    30253024      </p>
    30263025      <div id="rfc.figure.u.52"></div><pre class="inline"><span id="rfc.iref.g.56"></span>  <a href="#header.referer" class="smpl">Referer</a> = <a href="#imported.abnf" class="smpl">absolute-URI</a> / <a href="#imported.abnf" class="smpl">partial-URI</a>
    3027 </pre><p id="rfc.section.11.15.p.5">Example:</p>
     3026</pre><p id="rfc.section.10.15.p.5">Example:</p>
    30283027      <div id="rfc.figure.u.53"></div><pre class="text">  Referer: http://www.example.org/hypertext/Overview.html
    3029 </pre><p id="rfc.section.11.15.p.7">If the field value is a relative URI, it <em class="bcp14">SHOULD</em> be interpreted relative to the effective request URI. The URI <em class="bcp14">MUST NOT</em> include a fragment. See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;13.2</a> for security considerations.
     3028</pre><p id="rfc.section.10.15.p.7">If the field value is a relative URI, it <em class="bcp14">SHOULD</em> be interpreted relative to the effective request URI. The URI <em class="bcp14">MUST NOT</em> include a fragment. See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;12.2</a> for security considerations.
    30303029      </p>
    30313030      <div id="rfc.iref.r.3"></div>
    30323031      <div id="rfc.iref.h.17"></div>
    3033       <h2 id="rfc.section.11.16"><a href="#rfc.section.11.16">11.16</a>&nbsp;<a id="header.retry-after" href="#header.retry-after">Retry-After</a></h2>
    3034       <p id="rfc.section.11.16.p.1">The header "Retry-After" field can be used with a <a href="#status.503" class="smpl">503 (Service
     3032      <h2 id="rfc.section.10.16"><a href="#rfc.section.10.16">10.16</a>&nbsp;<a id="header.retry-after" href="#header.retry-after">Retry-After</a></h2>
     3033      <p id="rfc.section.10.16.p.1">The header "Retry-After" field can be used with a <a href="#status.503" class="smpl">503 (Service
    30353034            Unavailable)</a> response to indicate how long the service is expected to be unavailable to the requesting client. This field <em class="bcp14">MAY</em> also be used with any <a href="#status.3xx" class="smpl">3xx (Redirection)</a> response to indicate the minimum time the user-agent is asked to wait before issuing the redirected request.
    30363035      </p>
    3037       <p id="rfc.section.11.16.p.2">The value of this field can be either an HTTP-date or an integer number of seconds (in decimal) after the time of the response.</p>
     3036      <p id="rfc.section.10.16.p.2">The value of this field can be either an HTTP-date or an integer number of seconds (in decimal) after the time of the response.</p>
    30383037      <div id="rfc.figure.u.54"></div><pre class="inline"><span id="rfc.iref.g.57"></span>  <a href="#header.retry-after" class="smpl">Retry-After</a> = <a href="#http.date" class="smpl">HTTP-date</a> / <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>
    30393038</pre><div id="rule.delta-seconds">
    3040          <p id="rfc.section.11.16.p.4">  Time spans are non-negative decimal integers, representing time in seconds.</p>
     3039         <p id="rfc.section.10.16.p.4">  Time spans are non-negative decimal integers, representing time in seconds.</p>
    30413040      </div>
    30423041      <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.58"></span>  <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>  = 1*<a href="#imported.abnf" class="smpl">DIGIT</a>
    3043 </pre><p id="rfc.section.11.16.p.6">Two examples of its use are</p>
     3042</pre><p id="rfc.section.10.16.p.6">Two examples of its use are</p>
    30443043      <div id="rfc.figure.u.56"></div><pre class="text">  Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
    30453044  Retry-After: 120
    3046 </pre><p id="rfc.section.11.16.p.8">In the latter example, the delay is 2 minutes.</p>
     3045</pre><p id="rfc.section.10.16.p.8">In the latter example, the delay is 2 minutes.</p>
    30473046      <div id="rfc.iref.s.44"></div>
    30483047      <div id="rfc.iref.h.18"></div>
    3049       <h2 id="rfc.section.11.17"><a href="#rfc.section.11.17">11.17</a>&nbsp;<a id="header.server" href="#header.server">Server</a></h2>
    3050       <p id="rfc.section.11.17.p.1">The "Server" header field contains information about the software used by the origin server to handle the request.</p>
    3051       <p id="rfc.section.11.17.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;8.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.29"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for
     3048      <h2 id="rfc.section.10.17"><a href="#rfc.section.10.17">10.17</a>&nbsp;<a id="header.server" href="#header.server">Server</a></h2>
     3049      <p id="rfc.section.10.17.p.1">The "Server" header field contains information about the software used by the origin server to handle the request.</p>
     3050      <p id="rfc.section.10.17.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;8.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.29"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for
    30523051         identifying the application.
    30533052      </p>
    30543053      <div id="rfc.figure.u.57"></div><pre class="inline"><span id="rfc.iref.g.59"></span>  <a href="#header.server" class="smpl">Server</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#imported.abnf" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#imported.abnf" class="smpl">comment</a> ) )
    3055 </pre><p id="rfc.section.11.17.p.4">Example:</p>
     3054</pre><p id="rfc.section.10.17.p.4">Example:</p>
    30563055      <div id="rfc.figure.u.58"></div><pre class="text">  Server: CERN/3.0 libwww/2.17
    3057 </pre><p id="rfc.section.11.17.p.6">If the response is being forwarded through a proxy, the proxy application <em class="bcp14">MUST NOT</em> modify the <a href="#header.server" class="smpl">Server</a> header field. Instead, it <em class="bcp14">MUST</em> include a <a href="p1-messaging.html#header.via" class="smpl">Via</a> field (as described in <a href="p1-messaging.html#header.via" title="Via">Section 5.7</a> of <a href="#Part1" id="rfc.xref.Part1.30"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    3058       </p>
    3059       <div class="note" id="rfc.section.11.17.p.7">
     3056</pre><p id="rfc.section.10.17.p.6">If the response is being forwarded through a proxy, the proxy application <em class="bcp14">MUST NOT</em> modify the <a href="#header.server" class="smpl">Server</a> header field. Instead, it <em class="bcp14">MUST</em> include a <a href="p1-messaging.html#header.via" class="smpl">Via</a> field (as described in <a href="p1-messaging.html#header.via" title="Via">Section 5.7</a> of <a href="#Part1" id="rfc.xref.Part1.30"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
     3057      </p>
     3058      <div class="note" id="rfc.section.10.17.p.7">
    30603059         <p> <b>Note:</b> Revealing the specific software version of the server might allow the server machine to become more vulnerable to attacks
    30613060            against software that is known to contain security holes. Server implementers are encouraged to make this field a configurable
    … …  
    30653064      <div id="rfc.iref.u.1"></div>
    30663065      <div id="rfc.iref.h.19"></div>
    3067       <h2 id="rfc.section.11.18"><a href="#rfc.section.11.18">11.18</a>&nbsp;<a id="header.user-agent" href="#header.user-agent">User-Agent</a></h2>
    3068       <p id="rfc.section.11.18.p.1">The "User-Agent" header field contains information about the user agent originating the request. User agents <em class="bcp14">SHOULD</em> include this field with requests.
    3069       </p>
    3070       <p id="rfc.section.11.18.p.2">Typically, it is used for statistical purposes, the tracing of protocol violations, and tailoring responses to avoid particular
     3066      <h2 id="rfc.section.10.18"><a href="#rfc.section.10.18">10.18</a>&nbsp;<a id="header.user-agent" href="#header.user-agent">User-Agent</a></h2>
     3067      <p id="rfc.section.10.18.p.1">The "User-Agent" header field contains information about the user agent originating the request. User agents <em class="bcp14">SHOULD</em> include this field with requests.
     3068      </p>
     3069      <p id="rfc.section.10.18.p.2">Typically, it is used for statistical purposes, the tracing of protocol violations, and tailoring responses to avoid particular
    30713070         user agent limitations.
    30723071      </p>
    3073       <p id="rfc.section.11.18.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;8.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.31"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance
     3072      <p id="rfc.section.10.18.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;8.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.31"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance
    30743073         for identifying the application.
    30753074      </p>
    3076       <p id="rfc.section.11.18.p.4">Because this field is usually sent on every request a user agent makes, implementations are encouraged not to include needlessly
     3075      <p id="rfc.section.10.18.p.4">Because this field is usually sent on every request a user agent makes, implementations are encouraged not to include needlessly
    30773076         fine-grained detail, and to limit (or even prohibit) the addition of subproducts by third parties. Overly long and detailed
    30783077         User-Agent field values make requests larger and can also be used to identify ("fingerprint") the user against their wishes.
    30793078      </p>
    3080       <p id="rfc.section.11.18.p.5">Likewise, implementations are encouraged not to use the product tokens of other implementations in order to declare compatibility
     3079      <p id="rfc.section.10.18.p.5">Likewise, implementations are encouraged not to use the product tokens of other implementations in order to declare compatibility
    30813080         with them, as this circumvents the purpose of the field. Finally, they are encouraged not to use comments to identify products;
    30823081         doing so makes the field value more difficult to parse.
    30833082      </p>
    30843083      <div id="rfc.figure.u.59"></div><pre class="inline"><span id="rfc.iref.g.60"></span>  <a href="#header.user-agent" class="smpl">User-Agent</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#imported.abnf" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#imported.abnf" class="smpl">comment</a> ) )
    3085 </pre><p id="rfc.section.11.18.p.7">Example:</p>
     3084</pre><p id="rfc.section.10.18.p.7">Example:</p>
    30863085      <div id="rfc.figure.u.60"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    3087 </pre><h1 id="rfc.section.12"><a href="#rfc.section.12">12.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
    3088       <h2 id="rfc.section.12.1"><a href="#rfc.section.12.1">12.1</a>&nbsp;<a id="method.registry" href="#method.registry">Method Registry</a></h2>
    3089       <p id="rfc.section.12.1.p.1">The HTTP Method Registry defines the name space for the request method token (<a href="#methods" title="Request Methods">Section&nbsp;4</a>). The method registry is maintained at &lt;<a href="http://www.iana.org/assignments/http-methods">http://www.iana.org/assignments/http-methods</a>&gt;.
    3090       </p>
    3091       <h3 id="rfc.section.12.1.1"><a href="#rfc.section.12.1.1">12.1.1</a>&nbsp;<a id="method.procedure" href="#method.procedure">Procedure</a></h3>
    3092       <p id="rfc.section.12.1.1.p.1">HTTP method registrations <em class="bcp14">MUST</em> include the following fields:
     3086</pre><h1 id="rfc.section.11"><a href="#rfc.section.11">11.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
     3087      <h2 id="rfc.section.11.1"><a href="#rfc.section.11.1">11.1</a>&nbsp;<a id="method.registry" href="#method.registry">Method Registry</a></h2>
     3088      <p id="rfc.section.11.1.p.1">The HTTP Method Registry defines the name space for the request method token (<a href="#methods" title="Request Methods">Section&nbsp;4</a>). The method registry is maintained at &lt;<a href="http://www.iana.org/assignments/http-methods">http://www.iana.org/assignments/http-methods</a>&gt;.
     3089      </p>
     3090      <h3 id="rfc.section.11.1.1"><a href="#rfc.section.11.1.1">11.1.1</a>&nbsp;<a id="method.procedure" href="#method.procedure">Procedure</a></h3>
     3091      <p id="rfc.section.11.1.1.p.1">HTTP method registrations <em class="bcp14">MUST</em> include the following fields:
    30933092      </p>
    30943093      <ul>
    … …  
    31013100         <li>Pointer to specification text</li>
    31023101      </ul>
    3103       <p id="rfc.section.12.1.1.p.2">Values to be added to this name space require IETF Review (see <a href="#RFC5226" id="rfc.xref.RFC5226.1"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
    3104       </p>
    3105       <h3 id="rfc.section.12.1.2"><a href="#rfc.section.12.1.2">12.1.2</a>&nbsp;<a id="considerations.for.new.methods" href="#considerations.for.new.methods">Considerations for New Methods</a></h3>
    3106       <p id="rfc.section.12.1.2.p.1">Standardized HTTP methods are generic; that is, they are potentially applicable to any resource, not just one particular media
     3102      <p id="rfc.section.11.1.1.p.2">Values to be added to this name space require IETF Review (see <a href="#RFC5226" id="rfc.xref.RFC5226.1"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
     3103      </p>
     3104      <h3 id="rfc.section.11.1.2"><a href="#rfc.section.11.1.2">11.1.2</a>&nbsp;<a id="considerations.for.new.methods" href="#considerations.for.new.methods">Considerations for New Methods</a></h3>
     3105      <p id="rfc.section.11.1.2.p.1">Standardized HTTP methods are generic; that is, they are potentially applicable to any resource, not just one particular media
    31073106         type, kind of resource, or application. As such, it is preferred that new HTTP methods be registered in a document that isn't
    31083107         specific to a single application or data format, since orthogonal technologies deserve orthogonal specification.
    31093108      </p>
    3110       <p id="rfc.section.12.1.2.p.2">Since HTTP message parsing (<a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.32"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) is independent of method semantics (aside from responses to HEAD), definitions of new HTTP methods cannot change the parsing
     3109      <p id="rfc.section.11.1.2.p.2">Since HTTP message parsing (<a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.32"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) is independent of method semantics (aside from responses to HEAD), definitions of new HTTP methods cannot change the parsing
    31113110         algorithm or prohibit the presence of a message body on either the request or the response message. Definitions of new methods
    31123111         can specify that only zero-length bodies are allowed, which would imply that each such messages would be required to contain
    31133112         a Content-Length header field with a value of "0".
    31143113      </p>
    3115       <p id="rfc.section.12.1.2.p.3">New method definitions need to indicate whether they are safe (<a href="#safe.methods" title="Safe Methods">Section&nbsp;4.2.1</a>), idempotent (<a href="#idempotent.methods" title="Idempotent Methods">Section&nbsp;4.2.2</a>), cacheable (<a href="#cacheable.methods" title="Cacheable Methods">Section&nbsp;4.2.3</a>), and what semantics are to be associated with the request body if any is present in the request. If a method is cacheable,
     3114      <p id="rfc.section.11.1.2.p.3">New method definitions need to indicate whether they are safe (<a href="#safe.methods" title="Safe Methods">Section&nbsp;4.2.1</a>), idempotent (<a href="#idempotent.methods" title="Idempotent Methods">Section&nbsp;4.2.2</a>), cacheable (<a href="#cacheable.methods" title="Cacheable Methods">Section&nbsp;4.2.3</a>), and what semantics are to be associated with the request body if any is present in the request. If a method is cacheable,
    31163115         the method definition ought to describe how, and under what conditions, a cache can store a response and use it to satisfy
    31173116         a subsequent request.
    31183117      </p>
    3119       <h3 id="rfc.section.12.1.3"><a href="#rfc.section.12.1.3">12.1.3</a>&nbsp;<a id="method.registration" href="#method.registration">Registrations</a></h3>
    3120       <p id="rfc.section.12.1.3.p.1">The HTTP Method Registry shall be populated with the registrations below:</p>
     3118      <h3 id="rfc.section.11.1.3"><a href="#rfc.section.11.1.3">11.1.3</a>&nbsp;<a id="method.registration" href="#method.registration">Registrations</a></h3>
     3119      <p id="rfc.section.11.1.3.p.1">The HTTP Method Registry shall be populated with the registrations below:</p>
    31213120      <div id="rfc.table.2">
    31223121         <div id="iana.method.registration.table"></div>
    … …  
    31903189         </table>
    31913190      </div>
    3192       <h2 id="rfc.section.12.2"><a href="#rfc.section.12.2">12.2</a>&nbsp;<a id="status.code.registry" href="#status.code.registry">Status Code Registry</a></h2>
    3193       <p id="rfc.section.12.2.p.1">The HTTP Status Code Registry defines the name space for the response status-code token (<a href="#status.codes" title="Response Status Codes">Section&nbsp;6</a>). The status code registry is maintained at &lt;<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>&gt;.
    3194       </p>
    3195       <p id="rfc.section.12.2.p.2">This section replaces the registration procedure for HTTP Status Codes previously defined in <a href="http://tools.ietf.org/html/rfc2817#section-7.1">Section 7.1</a> of <a href="#RFC2817" id="rfc.xref.RFC2817.1"><cite title="Upgrading to TLS Within HTTP/1.1">[RFC2817]</cite></a>.
    3196       </p>
    3197       <h3 id="rfc.section.12.2.1"><a href="#rfc.section.12.2.1">12.2.1</a>&nbsp;<a id="status.code.procedure" href="#status.code.procedure">Procedure</a></h3>
    3198       <p id="rfc.section.12.2.1.p.1">Values to be added to the HTTP status code name space require IETF Review (see <a href="#RFC5226" id="rfc.xref.RFC5226.2"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
    3199       </p>
    3200       <h3 id="rfc.section.12.2.2"><a href="#rfc.section.12.2.2">12.2.2</a>&nbsp;<a id="considerations.for.new.status.codes" href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></h3>
    3201       <p id="rfc.section.12.2.2.p.1">When it is necessary to express new semantics for a HTTP response that aren't specific to a single application or media type,
     3191      <h2 id="rfc.section.11.2"><a href="#rfc.section.11.2">11.2</a>&nbsp;<a id="status.code.registry" href="#status.code.registry">Status Code Registry</a></h2>
     3192      <p id="rfc.section.11.2.p.1">The HTTP Status Code Registry defines the name space for the response status-code token (<a href="#status.codes" title="Response Status Codes">Section&nbsp;6</a>). The status code registry is maintained at &lt;<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>&gt;.
     3193      </p>
     3194      <p id="rfc.section.11.2.p.2">This section replaces the registration procedure for HTTP Status Codes previously defined in <a href="http://tools.ietf.org/html/rfc2817#section-7.1">Section 7.1</a> of <a href="#RFC2817" id="rfc.xref.RFC2817.1"><cite title="Upgrading to TLS Within HTTP/1.1">[RFC2817]</cite></a>.
     3195      </p>
     3196      <h3 id="rfc.section.11.2.1"><a href="#rfc.section.11.2.1">11.2.1</a>&nbsp;<a id="status.code.procedure" href="#status.code.procedure">Procedure</a></h3>
     3197      <p id="rfc.section.11.2.1.p.1">Values to be added to the HTTP status code name space require IETF Review (see <a href="#RFC5226" id="rfc.xref.RFC5226.2"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
     3198      </p>
     3199      <h3 id="rfc.section.11.2.2"><a href="#rfc.section.11.2.2">11.2.2</a>&nbsp;<a id="considerations.for.new.status.codes" href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></h3>
     3200      <p id="rfc.section.11.2.2.p.1">When it is necessary to express new semantics for a HTTP response that aren't specific to a single application or media type,
    32023201         and currently defined status codes are inadequate, a new status code can be registered.
    32033202      </p>
    3204       <p id="rfc.section.12.2.2.p.2">HTTP status codes are generic; that is, they are potentially applicable to any resource, not just one particular media type,
     3203      <p id="rfc.section.11.2.2.p.2">HTTP status codes are generic; that is, they are potentially applicable to any resource, not just one particular media type,
    32053204         "type" of resource, or application. As such, it is preferred that new HTTP status codes be registered in a document that isn't
    32063205         specific to a single application, so that this is clear.
    32073206      </p>
    3208       <p id="rfc.section.12.2.2.p.3">Definitions of new HTTP status codes typically explain the request conditions that produce a response containing the status
     3207      <p id="rfc.section.11.2.2.p.3">Definitions of new HTTP status codes typically explain the request conditions that produce a response containing the status
    32093208         code (e.g., combinations of request header fields and/or method(s)), along with any interactions with response header fields
    32103209         (e.g., those that are required, those that modify the semantics of the response).
    32113210      </p>
    3212       <p id="rfc.section.12.2.2.p.4">New HTTP status codes are required to fall under one of the categories defined in <a href="#status.codes" title="Response Status Codes">Section&nbsp;6</a>. To allow existing parsers to properly handle them, new status codes cannot disallow a response body, although they can mandate
     3211      <p id="rfc.section.11.2.2.p.4">New HTTP status codes are required to fall under one of the categories defined in <a href="#status.codes" title="Response Status Codes">Section&nbsp;6</a>. To allow existing parsers to properly handle them, new status codes cannot disallow a response body, although they can mandate
    32133212         a zero-length response body. They can require the presence of one or more particular HTTP response header field(s).
    32143213      </p>
    3215       <p id="rfc.section.12.2.2.p.5">Likewise, their definitions can specify that caches are allowed to use heuristics to determine their freshness (see <a href="#Part6" id="rfc.xref.Part6.18"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>; by default, it is not allowed), and can define how to determine the resource which they carry a representation for (see <a href="#identifying.response.associated.with.representation" title="Identifying the Resource Associated with a Representation">Section&nbsp;3.1</a>; by default, it is anonymous).
    3216       </p>
    3217       <h3 id="rfc.section.12.2.3"><a href="#rfc.section.12.2.3">12.2.3</a>&nbsp;<a id="status.code.registration" href="#status.code.registration">Registrations</a></h3>
    3218       <p id="rfc.section.12.2.3.p.1">The HTTP Status Code Registry shall be updated with the registrations below:</p>
     3214      <p id="rfc.section.11.2.2.p.5">Likewise, their definitions can specify that caches are allowed to use heuristics to determine their freshness (see <a href="#Part6" id="rfc.xref.Part6.18"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>; by default, it is not allowed), and can define how to determine the resource which they carry a representation for (see <a href="#identifying.response.associated.with.representation" title="Identifying the Resource Associated with a Representation">Section&nbsp;3.1</a>; by default, it is anonymous).
     3215      </p>
     3216      <h3 id="rfc.section.11.2.3"><a href="#rfc.section.11.2.3">11.2.3</a>&nbsp;<a id="status.code.registration" href="#status.code.registration">Registrations</a></h3>
     3217      <p id="rfc.section.11.2.3.p.1">The HTTP Status Code Registry shall be updated with the registrations below:</p>
    32193218      <div id="rfc.table.3">
    32203219         <div id="iana.status.code.registration.table"></div>
    … …  
    34473446         </table>
    34483447      </div>
    3449       <h2 id="rfc.section.12.3"><a href="#rfc.section.12.3">12.3</a>&nbsp;<a id="header.field.registry" href="#header.field.registry">Header Field Registry</a></h2>
    3450       <p id="rfc.section.12.3.p.1">HTTP header fields are registered within the Message Header Field Registry located at &lt;<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>&gt;, as defined by <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>.
    3451       </p>
    3452       <h3 id="rfc.section.12.3.1"><a href="#rfc.section.12.3.1">12.3.1</a>&nbsp;<a id="considerations.for.new.header.fields" href="#considerations.for.new.header.fields">Considerations for New Header Fields</a></h3>
    3453       <p id="rfc.section.12.3.1.p.1">Header fields are key:value pairs that can be used to communicate data about the message, its payload, the target resource,
     3448      <h2 id="rfc.section.11.3"><a href="#rfc.section.11.3">11.3</a>&nbsp;<a id="header.field.registry" href="#header.field.registry">Header Field Registry</a></h2>
     3449      <p id="rfc.section.11.3.p.1">HTTP header fields are registered within the Message Header Field Registry located at &lt;<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>&gt;, as defined by <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>.
     3450      </p>
     3451      <h3 id="rfc.section.11.3.1"><a href="#rfc.section.11.3.1">11.3.1</a>&nbsp;<a id="considerations.for.new.header.fields" href="#considerations.for.new.header.fields">Considerations for New Header Fields</a></h3>
     3452      <p id="rfc.section.11.3.1.p.1">Header fields are key:value pairs that can be used to communicate data about the message, its payload, the target resource,
    34543453         or the connection (i.e., control data). See <a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.33"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a> for a general definition of header field syntax in HTTP messages.
    34553454      </p>
    3456       <p id="rfc.section.12.3.1.p.2">The requirements for header field names are defined in <a href="http://tools.ietf.org/html/rfc3864#section-4.1">Section 4.1</a> of <a href="#RFC3864" id="rfc.xref.RFC3864.2"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>. Authors of specifications defining new fields are advised to keep the name as short as practical, and not to prefix them
     3455      <p id="rfc.section.11.3.1.p.2">The requirements for header field names are defined in <a href="http://tools.ietf.org/html/rfc3864#section-4.1">Section 4.1</a> of <a href="#RFC3864" id="rfc.xref.RFC3864.2"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>. Authors of specifications defining new fields are advised to keep the name as short as practical, and not to prefix them
    34573456         with "X-" if they are to be registered (either immediately or in the future).
    34583457      </p>
    3459       <p id="rfc.section.12.3.1.p.3">New header field values typically have their syntax defined using ABNF (<a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>), using the extension defined in <a href="p1-messaging.html#abnf.extension" title="ABNF list extension: #rule">Appendix B</a> of <a href="#Part1" id="rfc.xref.Part1.34"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a> as necessary, and are usually constrained to the range of ASCII characters. Header fields needing a greater range of characters
     3458      <p id="rfc.section.11.3.1.p.3">New header field values typically have their syntax defined using ABNF (<a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>), using the extension defined in <a href="p1-messaging.html#abnf.extension" title="ABNF list extension: #rule">Appendix B</a> of <a href="#Part1" id="rfc.xref.Part1.34"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a> as necessary, and are usually constrained to the range of ASCII characters. Header fields needing a greater range of characters
    34603459         can use an encoding such as the one defined in <a href="#RFC5987" id="rfc.xref.RFC5987.1"><cite title="Character Set and Language Encoding for Hypertext Transfer Protocol (HTTP) Header Field Parameters">[RFC5987]</cite></a>.
    34613460      </p>
    3462       <p id="rfc.section.12.3.1.p.4">Because commas (",") are used as a generic delimiter between field-values, they need to be treated with care if they are allowed
     3461      <p id="rfc.section.11.3.1.p.4">Because commas (",") are used as a generic delimiter between field-values, they need to be treated with care if they are allowed
    34633462         in the field-value's payload. Typically, components that might contain a comma are protected with double-quotes using the
    34643463         quoted-string ABNF production (<a href="p1-messaging.html#field.components" title="Field value components">Section 3.2.4</a> of <a href="#Part1" id="rfc.xref.Part1.35"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    34653464      </p>
    3466       <p id="rfc.section.12.3.1.p.5">For example, a textual date and a URI (either of which might contain a comma) could be safely carried in field-values like
     3465      <p id="rfc.section.11.3.1.p.5">For example, a textual date and a URI (either of which might contain a comma) could be safely carried in field-values like
    34673466         these:
    34683467      </p>
    … …  
    34703469                     "http://without-a-comma.example.com/"
    34713470  Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005"
    3472 </pre><p id="rfc.section.12.3.1.p.7">Note that double-quote delimiters almost always are used with the quoted-string production; using a different syntax inside
     3471</pre><p id="rfc.section.11.3.1.p.7">Note that double-quote delimiters almost always are used with the quoted-string production; using a different syntax inside
    34733472         double-quotes will likely cause unnecessary confusion.
    34743473      </p>
    3475       <p id="rfc.section.12.3.1.p.8">Many header fields use a format including (case-insensitively) named parameters (for instance, <a href="#header.content-type" class="smpl">Content-Type</a>, defined in <a href="#header.content-type" id="rfc.xref.header.content-type.4" title="Content-Type">Section&nbsp;11.9</a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing
     3474      <p id="rfc.section.11.3.1.p.8">Many header fields use a format including (case-insensitively) named parameters (for instance, <a href="#header.content-type" class="smpl">Content-Type</a>, defined in <a href="#header.content-type" id="rfc.xref.header.content-type.4" title="Content-Type">Section&nbsp;10.9</a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing
    34763475         parser components. When allowing both forms, the meaning of a parameter value ought to be independent of the syntax used for
    34773476         it (for an example, see the notes on parameter handling for media types in <a href="#media.types" title="Media Types">Section&nbsp;8.5</a>).
    34783477      </p>
    3479       <p id="rfc.section.12.3.1.p.9">Authors of specifications defining new header fields are advised to consider documenting: </p>
     3478      <p id="rfc.section.11.3.1.p.9">Authors of specifications defining new header fields are advised to consider documenting: </p>
    34803479      <ul>
    34813480         <li>
    … …  
    35143513         </li>
    35153514      </ul>
    3516       <h3 id="rfc.section.12.3.2"><a href="#rfc.section.12.3.2">12.3.2</a>&nbsp;<a id="header.field.registration" href="#header.field.registration">Registrations</a></h3>
    3517       <p id="rfc.section.12.3.2.p.1">The Message Header Field Registry shall be updated with the following permanent registrations:</p>
     3515      <h3 id="rfc.section.11.3.2"><a href="#rfc.section.11.3.2">11.3.2</a>&nbsp;<a id="header.field.registration" href="#header.field.registration">Registrations</a></h3>
     3516      <p id="rfc.section.11.3.2.p.1">The Message Header Field Registry shall be updated with the following permanent registrations:</p>
    35183517      <div id="rfc.table.4">
    35193518         <div id="iana.header.registration.table"></div>
    … …  
    35323531                  <td class="left">http</td>
    35333532                  <td class="left">standard</td>
    3534                   <td class="left"> <a href="#header.accept" id="rfc.xref.header.accept.4" title="Accept">Section&nbsp;11.1</a>
     3533                  <td class="left"> <a href="#header.accept" id="rfc.xref.header.accept.4" title="Accept">Section&nbsp;10.1</a>
    35353534                  </td>
    35363535               </tr>
    … …  
    35393538                  <td class="left">http</td>
    35403539                  <td class="left">standard</td>
    3541                   <td class="left"> <a href="#header.accept-charset" id="rfc.xref.header.accept-charset.3" title="Accept-Charset">Section&nbsp;11.2</a>
     3540                  <td class="left"> <a href="#header.accept-charset" id="rfc.xref.header.accept-charset.3" title="Accept-Charset">Section&nbsp;10.2</a>
    35423541                  </td>
    35433542               </tr>
    … …  
    35463545                  <td class="left">http</td>
    35473546                  <td class="left">standard</td>
    3548                   <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.4" title="Accept-Encoding">Section&nbsp;11.3</a>
     3547                  <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.4" title="Accept-Encoding">Section&nbsp;10.3</a>
    35493548                  </td>
    35503549               </tr>
    … …  
    35533552                  <td class="left">http</td>
    35543553                  <td class="left">standard</td>
    3555                   <td class="left"> <a href="#header.accept-language" id="rfc.xref.header.accept-language.3" title="Accept-Language">Section&nbsp;11.4</a>
     3554                  <td class="left"> <a href="#header.accept-language" id="rfc.xref.header.accept-language.3" title="Accept-Language">Section&nbsp;10.4</a>
    35563555                  </td>
    35573556               </tr>
    … …  
    35603559                  <td class="left">http</td>
    35613560                  <td class="left">standard</td>
    3562                   <td class="left"> <a href="#header.allow" id="rfc.xref.header.allow.3" title="Allow">Section&nbsp;11.5</a>
     3561                  <td class="left"> <a href="#header.allow" id="rfc.xref.header.allow.3" title="Allow">Section&nbsp;10.5</a>
    35633562                  </td>
    35643563               </tr>
    … …  
    35673566                  <td class="left">http</td>
    35683567                  <td class="left">standard</td>
    3569                   <td class="left"> <a href="#header.content-encoding" id="rfc.xref.header.content-encoding.3" title="Content-Encoding">Section&nbsp;11.6</a>
     3568                  <td class="left"> <a href="#header.content-encoding" id="rfc.xref.header.content-encoding.3" title="Content-Encoding">Section&nbsp;10.6</a>
    35703569                  </td>
    35713570               </tr>
    … …  
    35743573                  <td class="left">http</td>
    35753574                  <td class="left">standard</td>
    3576                   <td class="left"> <a href="#header.content-language" id="rfc.xref.header.content-language.2" title="Content-Language">Section&nbsp;11.7</a>
     3575                  <td class="left"> <a href="#header.content-language" id="rfc.xref.header.content-language.2" title="Content-Language">Section&nbsp;10.7</a>
    35773576                  </td>
    35783577               </tr>
    … …  
    35813580                  <td class="left">http</td>
    35823581                  <td class="left">standard</td>
    3583                   <td class="left"> <a href="#header.content-location" id="rfc.xref.header.content-location.4" title="Content-Location">Section&nbsp;11.8</a>
     3582                  <td class="left"> <a href="#header.content-location" id="rfc.xref.header.content-location.4" title="Content-Location">Section&nbsp;10.8</a>
    35843583                  </td>
    35853584               </tr>
    … …  
    35883587                  <td class="left">http</td>
    35893588                  <td class="left">standard</td>
    3590                   <td class="left"> <a href="#header.content-type" id="rfc.xref.header.content-type.5" title="Content-Type">Section&nbsp;11.9</a>
     3589                  <td class="left"> <a href="#header.content-type" id="rfc.xref.header.content-type.5" title="Content-Type">Section&nbsp;10.9</a>
    35913590                  </td>
    35923591               </tr>
    … …  
    35953594                  <td class="left">http</td>
    35963595                  <td class="left">standard</td>
    3597                   <td class="left"> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;11.10</a>
     3596                  <td class="left"> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;10.10</a>
    35983597                  </td>
    35993598               </tr>
    … …  
    36023601                  <td class="left">http</td>
    36033602                  <td class="left">standard</td>
    3604                   <td class="left"> <a href="#header.expect" id="rfc.xref.header.expect.3" title="Expect">Section&nbsp;11.11</a>
     3603                  <td class="left"> <a href="#header.expect" id="rfc.xref.header.expect.3" title="Expect">Section&nbsp;10.11</a>
    36053604                  </td>
    36063605               </tr>
    … …  
    36093608                  <td class="left">http</td>
    36103609                  <td class="left">standard</td>
    3611                   <td class="left"> <a href="#header.from" id="rfc.xref.header.from.2" title="From">Section&nbsp;11.12</a>
     3610                  <td class="left"> <a href="#header.from" id="rfc.xref.header.from.2" title="From">Section&nbsp;10.12</a>
    36123611                  </td>
    36133612               </tr>
    … …  
    36163615                  <td class="left">http</td>
    36173616                  <td class="left">standard</td>
    3618                   <td class="left"> <a href="#header.location" id="rfc.xref.header.location.4" title="Location">Section&nbsp;11.13</a>
     3617                  <td class="left"> <a href="#header.location" id="rfc.xref.header.location.4" title="Location">Section&nbsp;10.13</a>
    36193618                  </td>
    36203619               </tr>
    … …  
    36303629                  <td class="left">http</td>
    36313630                  <td class="left">standard</td>
    3632                   <td class="left"> <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.4" title="Max-Forwards">Section&nbsp;11.14</a>
     3631                  <td class="left"> <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.4" title="Max-Forwards">Section&nbsp;10.14</a>
    36333632                  </td>
    36343633               </tr>
    … …  
    36373636                  <td class="left">http</td>
    36383637                  <td class="left">standard</td>
    3639                   <td class="left"> <a href="#header.referer" id="rfc.xref.header.referer.2" title="Referer">Section&nbsp;11.15</a>
     3638                  <td class="left"> <a href="#header.referer" id="rfc.xref.header.referer.2" title="Referer">Section&nbsp;10.15</a>
    36403639                  </td>
    36413640               </tr>
    … …  
    36443643                  <td class="left">http</td>
    36453644                  <td class="left">standard</td>
    3646                   <td class="left"> <a href="#header.retry-after" id="rfc.xref.header.retry-after.3" title="Retry-After">Section&nbsp;11.16</a>
     3645                  <td class="left"> <a href="#header.retry-after" id="rfc.xref.header.retry-after.3" title="Retry-After">Section&nbsp;10.16</a>
    36473646                  </td>
    36483647               </tr>
    … …  
    36513650                  <td class="left">http</td>
    36523651                  <td class="left">standard</td>
    3653                   <td class="left"> <a href="#header.server" id="rfc.xref.header.server.2" title="Server">Section&nbsp;11.17</a>
     3652                  <td class="left"> <a href="#header.server" id="rfc.xref.header.server.2" title="Server">Section&nbsp;10.17</a>
    36543653                  </td>
    36553654               </tr>
    … …  
    36583657                  <td class="left">http</td>
    36593658                  <td class="left">standard</td>
    3660                   <td class="left"> <a href="#header.user-agent" id="rfc.xref.header.user-agent.3" title="User-Agent">Section&nbsp;11.18</a>
     3659                  <td class="left"> <a href="#header.user-agent" id="rfc.xref.header.user-agent.3" title="User-Agent">Section&nbsp;10.18</a>
    36613660                  </td>
    36623661               </tr>
    … …  
    36643663         </table>
    36653664      </div>
    3666       <p id="rfc.section.12.3.2.p.2">The change controller for the above registrations is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
    3667       <h2 id="rfc.section.12.4"><a href="#rfc.section.12.4">12.4</a>&nbsp;<a id="content.coding.registry" href="#content.coding.registry">Content Coding Registry</a></h2>
    3668       <p id="rfc.section.12.4.p.1">The HTTP Content Coding Registry defines the name space for content coding names (<a href="p1-messaging.html#compression.codings" title="Compression Codings">Section 4.2</a> of <a href="#Part1" id="rfc.xref.Part1.39"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>). The content coding registry is maintained at &lt;<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>&gt;.
    3669       </p>
    3670       <h3 id="rfc.section.12.4.1"><a href="#rfc.section.12.4.1">12.4.1</a>&nbsp;<a id="content.coding.procedure" href="#content.coding.procedure">Procedure</a></h3>
    3671       <p id="rfc.section.12.4.1.p.1">Content Coding registrations <em class="bcp14">MUST</em> include the following fields:
     3665      <p id="rfc.section.11.3.2.p.2">The change controller for the above registrations is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
     3666      <h2 id="rfc.section.11.4"><a href="#rfc.section.11.4">11.4</a>&nbsp;<a id="content.coding.registry" href="#content.coding.registry">Content Coding Registry</a></h2>
     3667      <p id="rfc.section.11.4.p.1">The HTTP Content Coding Registry defines the name space for content coding names (<a href="p1-messaging.html#compression.codings" title="Compression Codings">Section 4.2</a> of <a href="#Part1" id="rfc.xref.Part1.39"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>). The content coding registry is maintained at &lt;<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>&gt;.
     3668      </p>
     3669      <h3 id="rfc.section.11.4.1"><a href="#rfc.section.11.4.1">11.4.1</a>&nbsp;<a id="content.coding.procedure" href="#content.coding.procedure">Procedure</a></h3>
     3670      <p id="rfc.section.11.4.1.p.1">Content Coding registrations <em class="bcp14">MUST</em> include the following fields:
    36723671      </p>
    36733672      <ul>
    … …  
    36763675         <li>Pointer to specification text</li>
    36773676      </ul>
    3678       <p id="rfc.section.12.4.1.p.2">Names of content codings <em class="bcp14">MUST NOT</em> overlap with names of transfer codings (<a href="p1-messaging.html#transfer.codings" title="Transfer Codings">Section 4</a> of <a href="#Part1" id="rfc.xref.Part1.40"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>), unless the encoding transformation is identical (as is the case for the compression codings defined in <a href="p1-messaging.html#compression.codings" title="Compression Codings">Section 4.2</a> of <a href="#Part1" id="rfc.xref.Part1.41"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    3679       </p>
    3680       <p id="rfc.section.12.4.1.p.3">Values to be added to this name space require IETF Review (see <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a> of <a href="#RFC5226" id="rfc.xref.RFC5226.3"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>), and <em class="bcp14">MUST</em> conform to the purpose of content coding defined in this section.
    3681       </p>
    3682       <h3 id="rfc.section.12.4.2"><a href="#rfc.section.12.4.2">12.4.2</a>&nbsp;<a id="content.coding.registration" href="#content.coding.registration">Registrations</a></h3>
    3683       <p id="rfc.section.12.4.2.p.1">The HTTP Content Codings Registry shall be updated with the registrations below:</p>
     3677      <p id="rfc.section.11.4.1.p.2">Names of content codings <em class="bcp14">MUST NOT</em> overlap with names of transfer codings (<a href="p1-messaging.html#transfer.codings" title="Transfer Codings">Section 4</a> of <a href="#Part1" id="rfc.xref.Part1.40"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>), unless the encoding transformation is identical (as is the case for the compression codings defined in <a href="p1-messaging.html#compression.codings" title="Compression Codings">Section 4.2</a> of <a href="#Part1" id="rfc.xref.Part1.41"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
     3678      </p>
     3679      <p id="rfc.section.11.4.1.p.3">Values to be added to this name space require IETF Review (see <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a> of <a href="#RFC5226" id="rfc.xref.RFC5226.3"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>), and <em class="bcp14">MUST</em> conform to the purpose of content coding defined in this section.
     3680      </p>
     3681      <h3 id="rfc.section.11.4.2"><a href="#rfc.section.11.4.2">11.4.2</a>&nbsp;<a id="content.coding.registration" href="#content.coding.registration">Registrations</a></h3>
     3682      <p id="rfc.section.11.4.2.p.1">The HTTP Content Codings Registry shall be updated with the registrations below:</p>
    36843683      <div id="rfc.table.5">
    36853684         <div id="iana.content.coding.registration.table"></div>
    … …  
    37163715                  <td class="left">reserved (synonym for "no encoding" in <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> header field)
    37173716                  </td>
    3718                   <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.5" title="Accept-Encoding">Section&nbsp;11.3</a>
     3717                  <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.5" title="Accept-Encoding">Section&nbsp;10.3</a>
    37193718                  </td>
    37203719               </tr>
    … …  
    37223721         </table>
    37233722      </div>
    3724       <h1 id="rfc.section.13"><a href="#rfc.section.13">13.</a>&nbsp;<a id="security.considerations" href="#security.considerations">Security Considerations</a></h1>
    3725       <p id="rfc.section.13.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
     3723      <h1 id="rfc.section.12"><a href="#rfc.section.12">12.</a>&nbsp;<a id="security.considerations" href="#security.considerations">Security Considerations</a></h1>
     3724      <p id="rfc.section.12.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
    37263725         as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does
    37273726         make some suggestions for reducing security risks.
    37283727      </p>
    3729       <h2 id="rfc.section.13.1"><a href="#rfc.section.13.1">13.1</a>&nbsp;<a id="security.sensitive" href="#security.sensitive">Transfer of Sensitive Information</a></h2>
    3730       <p id="rfc.section.13.1.p.1">Like any generic data transfer protocol, HTTP cannot regulate the content of the data that is transferred, nor is there any
     3728      <h2 id="rfc.section.12.1"><a href="#rfc.section.12.1">12.1</a>&nbsp;<a id="security.sensitive" href="#security.sensitive">Transfer of Sensitive Information</a></h2>
     3729      <p id="rfc.section.12.1.p.1">Like any generic data transfer protocol, HTTP cannot regulate the content of the data that is transferred, nor is there any
    37313730         a priori method of determining the sensitivity of any particular piece of information within the context of any given request.
    37323731         Therefore, applications <em class="bcp14">SHOULD</em> supply as much control over this information as possible to the provider of that information. Four header fields are worth
    37333732         special mention in this context: <a href="#header.server" class="smpl">Server</a>, <a href="p1-messaging.html#header.via" class="smpl">Via</a>, <a href="#header.referer" class="smpl">Referer</a> and <a href="#header.from" class="smpl">From</a>.
    37343733      </p>
    3735       <p id="rfc.section.13.1.p.2">Revealing the specific software version of the server might allow the server machine to become more vulnerable to attacks
     3734      <p id="rfc.section.12.1.p.2">Revealing the specific software version of the server might allow the server machine to become more vulnerable to attacks
    37363735         against software that is known to contain security holes. Implementers <em class="bcp14">SHOULD</em> make the <a href="#header.server" class="smpl">Server</a> header field a configurable option.
    37373736      </p>
    3738       <p id="rfc.section.13.1.p.3">Proxies which serve as a portal through a network firewall <em class="bcp14">SHOULD</em> take special precautions regarding the transfer of header information that identifies the hosts behind the firewall. In particular,
     3737      <p id="rfc.section.12.1.p.3">Proxies which serve as a portal through a network firewall <em class="bcp14">SHOULD</em> take special precautions regarding the transfer of header information that identifies the hosts behind the firewall. In particular,
    37393738         they <em class="bcp14">SHOULD</em> remove, or replace with sanitized versions, any <a href="p1-messaging.html#header.via" class="smpl">Via</a> fields generated behind the firewall.
    37403739      </p>
    3741       <p id="rfc.section.13.1.p.4">The <a href="#header.referer" class="smpl">Referer</a> header field allows reading patterns to be studied and reverse links drawn. Although it can be very useful, its power can
     3740      <p id="rfc.section.12.1.p.4">The <a href="#header.referer" class="smpl">Referer</a> header field allows reading patterns to be studied and reverse links drawn. Although it can be very useful, its power can
    37423741         be abused if user details are not separated from the information contained in the Referer. Even when the personal information
    37433742         has been removed, the Referer header field might indicate a private document's URI whose publication would be inappropriate.
    37443743      </p>
    3745       <p id="rfc.section.13.1.p.5">The information sent in the <a href="#header.from" class="smpl">From</a> field might conflict with the user's privacy interests or their site's security policy, and hence it <em class="bcp14">SHOULD NOT</em> be transmitted without the user being able to disable, enable, and modify the contents of the field. The user <em class="bcp14">MUST</em> be able to set the contents of this field within a user preference or application defaults configuration.
    3746       </p>
    3747       <p id="rfc.section.13.1.p.6">We suggest, though do not require, that a convenient toggle interface be provided for the user to enable or disable the sending
     3744      <p id="rfc.section.12.1.p.5">The information sent in the <a href="#header.from" class="smpl">From</a> field might conflict with the user's privacy interests or their site's security policy, and hence it <em class="bcp14">SHOULD NOT</em> be transmitted without the user being able to disable, enable, and modify the contents of the field. The user <em class="bcp14">MUST</em> be able to set the contents of this field within a user preference or application defaults configuration.
     3745      </p>
     3746      <p id="rfc.section.12.1.p.6">We suggest, though do not require, that a convenient toggle interface be provided for the user to enable or disable the sending
    37483747         of <a href="#header.from" class="smpl">From</a> and <a href="#header.referer" class="smpl">Referer</a> information.
    37493748      </p>
    3750       <p id="rfc.section.13.1.p.7">The <a href="#header.user-agent" class="smpl">User-Agent</a> (<a href="#header.user-agent" id="rfc.xref.header.user-agent.4" title="User-Agent">Section&nbsp;11.18</a>) or <a href="#header.server" class="smpl">Server</a> (<a href="#header.server" id="rfc.xref.header.server.3" title="Server">Section&nbsp;11.17</a>) header fields can sometimes be used to determine that a specific client or server has a particular security hole which might
     3749      <p id="rfc.section.12.1.p.7">The <a href="#header.user-agent" class="smpl">User-Agent</a> (<a href="#header.user-agent" id="rfc.xref.header.user-agent.4" title="User-Agent">Section&nbsp;10.18</a>) or <a href="#header.server" class="smpl">Server</a> (<a href="#header.server" id="rfc.xref.header.server.3" title="Server">Section&nbsp;10.17</a>) header fields can sometimes be used to determine that a specific client or server has a particular security hole which might
    37513750         be exploited. Unfortunately, this same information is often used for other valuable purposes for which HTTP currently has
    37523751         no better mechanism.
    37533752      </p>
    3754       <p id="rfc.section.13.1.p.8">Furthermore, the <a href="#header.user-agent" class="smpl">User-Agent</a> header field might contain enough entropy to be used, possibly in conjunction with other material, to uniquely identify the
     3753      <p id="rfc.section.12.1.p.8">Furthermore, the <a href="#header.user-agent" class="smpl">User-Agent</a> header field might contain enough entropy to be used, possibly in conjunction with other material, to uniquely identify the
    37553754         user.
    37563755      </p>
    3757       <p id="rfc.section.13.1.p.9">Some request methods, like TRACE (<a href="#TRACE" id="rfc.xref.TRACE.4" title="TRACE">Section&nbsp;4.3.8</a>), expose information that was sent in request header fields within the body of their response. Clients <em class="bcp14">SHOULD</em> be careful with sensitive information, like Cookies, Authorization credentials, and other header fields that might be used
     3756      <p id="rfc.section.12.1.p.9">Some request methods, like TRACE (<a href="#TRACE" id="rfc.xref.TRACE.4" title="TRACE">Section&nbsp;4.3.8</a>), expose information that was sent in request header fields within the body of their response. Clients <em class="bcp14">SHOULD</em> be careful with sensitive information, like Cookies, Authorization credentials, and other header fields that might be used
    37583757         to collect data from the client.
    37593758      </p>
    3760       <h2 id="rfc.section.13.2"><a href="#rfc.section.13.2">13.2</a>&nbsp;<a id="encoding.sensitive.information.in.uris" href="#encoding.sensitive.information.in.uris">Encoding Sensitive Information in URIs</a></h2>
    3761       <p id="rfc.section.13.2.p.1">Because the source of a link might be private information or might reveal an otherwise private information source, it is strongly
     3759      <h2 id="rfc.section.12.2"><a href="#rfc.section.12.2">12.2</a>&nbsp;<a id="encoding.sensitive.information.in.uris" href="#encoding.sensitive.information.in.uris">Encoding Sensitive Information in URIs</a></h2>
     3760      <p id="rfc.section.12.2.p.1">Because the source of a link might be private information or might reveal an otherwise private information source, it is strongly
    37623761         recommended that the user be able to select whether or not the <a href="#header.referer" class="smpl">Referer</a> field is sent. For example, a browser client could have a toggle switch for browsing openly/anonymously, which would respectively
    37633762         enable/disable the sending of Referer and From information.
    37643763      </p>
    3765       <p id="rfc.section.13.2.p.2">Clients <em class="bcp14">SHOULD NOT</em> include a <a href="#header.referer" class="smpl">Referer</a> header field in a (non-secure) HTTP request if the referring page was transferred with a secure protocol.
    3766       </p>
    3767       <p id="rfc.section.13.2.p.3">Authors of services <em class="bcp14">SHOULD NOT</em> use GET-based forms for the submission of sensitive data because that data will be placed in the request-target. Many existing
     3764      <p id="rfc.section.12.2.p.2">Clients <em class="bcp14">SHOULD NOT</em> include a <a href="#header.referer" class="smpl">Referer</a> header field in a (non-secure) HTTP request if the referring page was transferred with a secure protocol.
     3765      </p>
     3766      <p id="rfc.section.12.2.p.3">Authors of services <em class="bcp14">SHOULD NOT</em> use GET-based forms for the submission of sensitive data because that data will be placed in the request-target. Many existing
    37683767         servers, proxies, and user agents log or display the request-target in places where it might be visible to third parties.
    37693768         Such services can use POST-based form submission instead.
    37703769      </p>
    3771       <h2 id="rfc.section.13.3"><a href="#rfc.section.13.3">13.3</a>&nbsp;<a id="location.spoofing-leakage" href="#location.spoofing-leakage">Location Header Fields: Spoofing and Information Leakage</a></h2>
    3772       <p id="rfc.section.13.3.p.1">If a single server supports multiple organizations that do not trust one another, then it <em class="bcp14">MUST</em> check the values of <a href="#header.location" class="smpl">Location</a> and <a href="#header.content-location" class="smpl">Content-Location</a> header fields in responses that are generated under control of said organizations to make sure that they do not attempt to
     3770      <h2 id="rfc.section.12.3"><a href="#rfc.section.12.3">12.3</a>&nbsp;<a id="location.spoofing-leakage" href="#location.spoofing-leakage">Location Header Fields: Spoofing and Information Leakage</a></h2>
     3771      <p id="rfc.section.12.3.p.1">If a single server supports multiple organizations that do not trust one another, then it <em class="bcp14">MUST</em> check the values of <a href="#header.location" class="smpl">Location</a> and <a href="#header.content-location" class="smpl">Content-Location</a> header fields in responses that are generated under control of said organizations to make sure that they do not attempt to
    37733772         invalidate resources over which they have no authority.
    37743773      </p>
    3775       <p id="rfc.section.13.3.p.2">Furthermore, appending the fragment identifier from one URI to another one obtained from a <a href="#header.location" class="smpl">Location</a> header field might leak confidential information to the target server — although the fragment identifier is not transmitted
     3774      <p id="rfc.section.12.3.p.2">Furthermore, appending the fragment identifier from one URI to another one obtained from a <a href="#header.location" class="smpl">Location</a> header field might leak confidential information to the target server — although the fragment identifier is not transmitted
    37763775         in the final request, it might be visible to the user agent through other means, such as scripting.
    37773776      </p>
    3778       <h2 id="rfc.section.13.4"><a href="#rfc.section.13.4">13.4</a>&nbsp;Security Considerations for CONNECT
     3777      <h2 id="rfc.section.12.4"><a href="#rfc.section.12.4">12.4</a>&nbsp;Security Considerations for CONNECT
    37793778      </h2>
    3780       <p id="rfc.section.13.4.p.1">Since tunneled data is opaque to the proxy, there are additional risks to tunneling to other well-known or reserved ports.
     3779      <p id="rfc.section.12.4.p.1">Since tunneled data is opaque to the proxy, there are additional risks to tunneling to other well-known or reserved ports.
    37813780         A HTTP client CONNECTing to port 25 could relay spam via SMTP, for example. As such, proxies <em class="bcp14">SHOULD</em> restrict CONNECT access to a small number of known ports.
    37823781      </p>
    3783       <h2 id="rfc.section.13.5"><a href="#rfc.section.13.5">13.5</a>&nbsp;<a id="privacy.issues.connected.to.accept.header.fields" href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></h2>
    3784       <p id="rfc.section.13.5.p.1">Accept header fields can reveal information about the user to all servers which are accessed. The <a href="#header.accept-language" class="smpl">Accept-Language</a> header field in particular can reveal information the user would consider to be of a private nature, because the understanding
     3782      <h2 id="rfc.section.12.5"><a href="#rfc.section.12.5">12.5</a>&nbsp;<a id="privacy.issues.connected.to.accept.header.fields" href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></h2>
     3783      <p id="rfc.section.12.5.p.1">Accept header fields can reveal information about the user to all servers which are accessed. The <a href="#header.accept-language" class="smpl">Accept-Language</a> header field in particular can reveal information the user would consider to be of a private nature, because the understanding
    37853784         of particular languages is often strongly correlated to the membership of a particular ethnic group. User agents which offer
    37863785         the option to configure the contents of an Accept-Language header field to be sent in every request are strongly encouraged
    37873786         to let the configuration process include a message which makes the user aware of the loss of privacy involved.
    37883787      </p>
    3789       <p id="rfc.section.13.5.p.2">An approach that limits the loss of privacy would be for a user agent to omit the sending of Accept-Language header fields
     3788      <p id="rfc.section.12.5.p.2">An approach that limits the loss of privacy would be for a user agent to omit the sending of Accept-Language header fields
    37903789         by default, and to ask the user whether or not to start sending Accept-Language header fields to a server if it detects, by
    37913790         looking for any <a href="p6-cache.html#header.vary" class="smpl">Vary</a> header fields generated by the server, that such sending could improve the quality of service.
    37923791      </p>
    3793       <p id="rfc.section.13.5.p.3">Elaborate user-customized accept header fields sent in every request, in particular if these include quality values, can be
     3792      <p id="rfc.section.12.5.p.3">Elaborate user-customized accept header fields sent in every request, in particular if these include quality values, can be
    37943793         used by servers as relatively reliable and long-lived user identifiers. Such user identifiers would allow content providers
    37953794         to do click-trail tracking, and would allow collaborating content providers to match cross-server click-trails or form submissions
    … …  
    38003799         field configurability <em class="bcp14">SHOULD</em> warn users about the loss of privacy which can be involved.
    38013800      </p>
    3802       <h1 id="rfc.section.14"><a href="#rfc.section.14">14.</a>&nbsp;<a id="acks" href="#acks">Acknowledgments</a></h1>
    3803       <p id="rfc.section.14.p.1">See <a href="p1-messaging.html#acks" title="Acknowledgments">Section 9</a> of <a href="#Part1" id="rfc.xref.Part1.45"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
    3804       </p>
    3805       <h1 id="rfc.references"><a id="rfc.section.15" href="#rfc.section.15">15.</a> References
     3801      <h1 id="rfc.section.13"><a href="#rfc.section.13">13.</a>&nbsp;<a id="acks" href="#acks">Acknowledgments</a></h1>
     3802      <p id="rfc.section.13.p.1">See <a href="p1-messaging.html#acks" title="Acknowledgments">Section 9</a> of <a href="#Part1" id="rfc.xref.Part1.45"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
     3803      </p>
     3804      <h1 id="rfc.references"><a id="rfc.section.14" href="#rfc.section.14">14.</a> References
    38063805      </h1>
    3807       <h2 id="rfc.references.1"><a href="#rfc.section.15.1" id="rfc.section.15.1">15.1</a> Normative References
     3806      <h2 id="rfc.references.1"><a href="#rfc.section.14.1" id="rfc.section.14.1">14.1</a> Normative References
    38083807      </h2>
    38093808      <table>                             
    … …  
    38843883         </tr>
    38853884      </table>
    3886       <h2 id="rfc.references.2"><a href="#rfc.section.15.2" id="rfc.section.15.2">15.2</a> Informative References
     3885      <h2 id="rfc.references.2"><a href="#rfc.section.14.2" id="rfc.section.14.2">14.2</a> Informative References
    38873886      </h2>
    38883887      <table>                                           
    … …  
    40754074      </p>
    40764075      <h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a>&nbsp;<a id="changes.from.rfc.2616" href="#changes.from.rfc.2616">Changes from RFC 2616</a></h1>
    4077       <p id="rfc.section.C.p.1">Introduce Method Registry. (<a href="#method.registry" title="Method Registry">Section&nbsp;12.1</a>)
     4076      <p id="rfc.section.C.p.1">Introduce Method Registry. (<a href="#method.registry" title="Method Registry">Section&nbsp;11.1</a>)
    40784077      </p>
    40794078      <p id="rfc.section.C.p.2">Clarify definition of POST. (<a href="#POST" id="rfc.xref.POST.3" title="POST">Section&nbsp;4.3.3</a>)
    … …  
    40834082      <p id="rfc.section.C.p.4">Take over definition of CONNECT method from <a href="#RFC2817" id="rfc.xref.RFC2817.2"><cite title="Upgrading to TLS Within HTTP/1.1">[RFC2817]</cite></a>. (<a href="#CONNECT" id="rfc.xref.CONNECT.3" title="CONNECT">Section&nbsp;4.3.6</a>)
    40844083      </p>
    4085       <p id="rfc.section.C.p.5">Take over the Status Code Registry, previously defined in <a href="http://tools.ietf.org/html/rfc2817#section-7.1">Section 7.1</a> of <a href="#RFC2817" id="rfc.xref.RFC2817.3"><cite title="Upgrading to TLS Within HTTP/1.1">[RFC2817]</cite></a>. (<a href="#status.code.registry" title="Status Code Registry">Section&nbsp;12.2</a>)
     4084      <p id="rfc.section.C.p.5">Take over the Status Code Registry, previously defined in <a href="http://tools.ietf.org/html/rfc2817#section-7.1">Section 7.1</a> of <a href="#RFC2817" id="rfc.xref.RFC2817.3"><cite title="Upgrading to TLS Within HTTP/1.1">[RFC2817]</cite></a>. (<a href="#status.code.registry" title="Status Code Registry">Section&nbsp;11.2</a>)
    40864085      </p>
    40874086      <p id="rfc.section.C.p.6">Broadened the definition of <a href="#status.203" class="smpl">203 (Non-Authoritative Information)</a> to include cases of payload transformations as well. (<a href="#status.203" id="rfc.xref.status.203.3" title="203 Non-Authoritative Information">Section&nbsp;6.3.4</a>)
    … …  
    40994098      <p id="rfc.section.C.p.10">Define status <a href="#status.426" class="smpl">426 (Upgrade Required)</a> (this was incorporated from <a href="#RFC2817" id="rfc.xref.RFC2817.4"><cite title="Upgrading to TLS Within HTTP/1.1">[RFC2817]</cite></a>). (<a href="#status.426" id="rfc.xref.status.426.3" title="426 Upgrade Required">Section&nbsp;6.5.15</a>)
    41004099      </p>
    4101       <p id="rfc.section.C.p.11">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;11</a>)
     4100      <p id="rfc.section.C.p.11">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;10</a>)
    41024101      </p>
    41034102      <p id="rfc.section.C.p.12">Reclassify "<a href="#header.allow" class="smpl">Allow</a>" as response header field, removing the option to specify it in a PUT request. Relax the server requirement on the contents
    4104          of the Allow header field and remove requirement on clients to always trust the header field value. (<a href="#header.allow" id="rfc.xref.header.allow.4" title="Allow">Section&nbsp;11.5</a>)
     4103         of the Allow header field and remove requirement on clients to always trust the header field value. (<a href="#header.allow" id="rfc.xref.header.allow.4" title="Allow">Section&nbsp;10.5</a>)
    41054104      </p>
    41064105      <p id="rfc.section.C.p.13">The ABNF for the <a href="#header.expect" class="smpl">Expect</a> header field has been both fixed (allowing parameters for value-less expectations as well) and simplified (allowing trailing
    4107          semicolons after "100-continue" when they were invalid before). (<a href="#header.expect" id="rfc.xref.header.expect.4" title="Expect">Section&nbsp;11.11</a>)
     4106         semicolons after "100-continue" when they were invalid before). (<a href="#header.expect" id="rfc.xref.header.expect.4" title="Expect">Section&nbsp;10.11</a>)
    41084107      </p>
    41094108      <p id="rfc.section.C.p.14">Correct syntax of <a href="#header.location" class="smpl">Location</a> header field to allow URI references (including relative references and fragments), as referred symbol "absoluteURI" wasn't
    4110          what was expected, and add some clarifications as to when use of fragments would not be appropriate. (<a href="#header.location" id="rfc.xref.header.location.5" title="Location">Section&nbsp;11.13</a>)
    4111       </p>
    4112       <p id="rfc.section.C.p.15">Restrict <a href="#header.max-forwards" class="smpl">Max-Forwards</a> header field to OPTIONS and TRACE (previously, extension methods could have used it as well). (<a href="#header.max-forwards" id="rfc.xref.header.max-forwards.5" title="Max-Forwards">Section&nbsp;11.14</a>)
    4113       </p>
    4114       <p id="rfc.section.C.p.16">Allow <a href="#header.referer" class="smpl">Referer</a> field value of "about:blank" as alternative to not specifying it. (<a href="#header.referer" id="rfc.xref.header.referer.3" title="Referer">Section&nbsp;11.15</a>)
    4115       </p>
    4116       <p id="rfc.section.C.p.17">In the description of the <a href="#header.server" class="smpl">Server</a> header field, the <a href="p1-messaging.html#header.via" class="smpl">Via</a> field was described as a SHOULD. The requirement was and is stated correctly in the description of the Via header field in <a href="p1-messaging.html#header.via" title="Via">Section 5.7</a> of <a href="#Part1" id="rfc.xref.Part1.46"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>. (<a href="#header.server" id="rfc.xref.header.server.4" title="Server">Section&nbsp;11.17</a>)
     4109         what was expected, and add some clarifications as to when use of fragments would not be appropriate. (<a href="#header.location" id="rfc.xref.header.location.5" title="Location">Section&nbsp;10.13</a>)
     4110      </p>
     4111      <p id="rfc.section.C.p.15">Restrict <a href="#header.max-forwards" class="smpl">Max-Forwards</a> header field to OPTIONS and TRACE (previously, extension methods could have used it as well). (<a href="#header.max-forwards" id="rfc.xref.header.max-forwards.5" title="Max-Forwards">Section&nbsp;10.14</a>)
     4112      </p>
     4113      <p id="rfc.section.C.p.16">Allow <a href="#header.referer" class="smpl">Referer</a> field value of "about:blank" as alternative to not specifying it. (<a href="#header.referer" id="rfc.xref.header.referer.3" title="Referer">Section&nbsp;10.15</a>)
     4114      </p>
     4115      <p id="rfc.section.C.p.17">In the description of the <a href="#header.server" class="smpl">Server</a> header field, the <a href="p1-messaging.html#header.via" class="smpl">Via</a> field was described as a SHOULD. The requirement was and is stated correctly in the description of the Via header field in <a href="p1-messaging.html#header.via" title="Via">Section 5.7</a> of <a href="#Part1" id="rfc.xref.Part1.46"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>. (<a href="#header.server" id="rfc.xref.header.server.4" title="Server">Section&nbsp;10.17</a>)
    41174116      </p>
    41184117      <p id="rfc.section.C.p.18">Clarify contexts that charset is used in. (<a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;8.3</a>)
    41194118      </p>
    4120       <p id="rfc.section.C.p.19">Registration of Content Codings now requires IETF Review (<a href="#content.coding.registry" title="Content Coding Registry">Section&nbsp;12.4</a>)
     4119      <p id="rfc.section.C.p.19">Registration of Content Codings now requires IETF Review (<a href="#content.coding.registry" title="Content Coding Registry">Section&nbsp;11.4</a>)
    41214120      </p>
    41224121      <p id="rfc.section.C.p.20">Remove the default character encoding of "ISO-8859-1" for text media types; the default now is whatever the media type definition
    41234122         says. (<a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Section&nbsp;8.5.1</a>)
    41244123      </p>
    4125       <p id="rfc.section.C.p.21">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;11</a>)
     4124      <p id="rfc.section.C.p.21">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;10</a>)
    41264125      </p>
    41274126      <p id="rfc.section.C.p.22">Remove definition of Content-MD5 header field because it was inconsistently implemented with respect to partial responses,
    4128          and also because of known deficiencies in the hash algorithm itself (see <a href="#RFC6151" id="rfc.xref.RFC6151.1"><cite title="Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms">[RFC6151]</cite></a> for details). (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;11</a>)
    4129       </p>
    4130       <p id="rfc.section.C.p.23">Remove ISO-8859-1 special-casing in <a href="#header.accept-charset" class="smpl">Accept-Charset</a>. (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.4" title="Accept-Charset">Section&nbsp;11.2</a>)
     4127         and also because of known deficiencies in the hash algorithm itself (see <a href="#RFC6151" id="rfc.xref.RFC6151.1"><cite title="Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms">[RFC6151]</cite></a> for details). (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;10</a>)
     4128      </p>
     4129      <p id="rfc.section.C.p.23">Remove ISO-8859-1 special-casing in <a href="#header.accept-charset" class="smpl">Accept-Charset</a>. (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.4" title="Accept-Charset">Section&nbsp;10.2</a>)
    41314130      </p>
    41324131      <p id="rfc.section.C.p.24">Remove base URI setting semantics for <a href="#header.content-location" class="smpl">Content-Location</a> due to poor implementation support, which was caused by too many broken servers emitting bogus Content-Location header fields,
    4133          and also the potentially undesirable effect of potentially breaking relative links in content-negotiated resources. (<a href="#header.content-location" id="rfc.xref.header.content-location.5" title="Content-Location">Section&nbsp;11.8</a>)
     4132         and also the potentially undesirable effect of potentially breaking relative links in content-negotiated resources. (<a href="#header.content-location" id="rfc.xref.header.content-location.5" title="Content-Location">Section&nbsp;10.8</a>)
    41344133      </p>
    41354134      <p id="rfc.section.C.p.25">Remove reference to non-existant identity transfer-coding value tokens. (<a href="#no.content-transfer-encoding" id="rfc.xref.no.content-transfer-encoding.1" title="No Content-Transfer-Encoding">Appendix&nbsp;A.5</a>)
    … …  
    48604859         <ul class="ind">
    48614860            <li><a id="rfc.index.1" href="#rfc.index.1"><b>1</b></a><ul>
    4862                   <li>100 Continue (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.100.1">6.1</a>, <a href="#rfc.iref.24"><b>6.2.1</b></a>, <a href="#rfc.xref.status.100.2">12.2.3</a></li>
    4863                   <li>100-continue (expect value)&nbsp;&nbsp;<a href="#rfc.iref.142"><b>11.11</b></a></li>
    4864                   <li>101 Switching Protocols (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.101.1">6.1</a>, <a href="#rfc.iref.25"><b>6.2.2</b></a>, <a href="#rfc.xref.status.101.2">12.2.3</a></li>
    4865                   <li>1xx Informational (status code class)&nbsp;&nbsp;<a href="#rfc.iref.23"><b>6.2</b></a></li>
     4861                  <li>100 Continue (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.100.1">6.1</a>, <a href="#rfc.iref.26"><b>6.2.1</b></a>, <a href="#rfc.xref.status.100.2">11.2.3</a></li>
     4862                  <li>100-continue (expect value)&nbsp;&nbsp;<a href="#rfc.iref.142"><b>10.11</b></a></li>
     4863                  <li>101 Switching Protocols (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.101.1">6.1</a>, <a href="#rfc.iref.27"><b>6.2.2</b></a>, <a href="#rfc.xref.status.101.2">11.2.3</a></li>
     4864                  <li>1xx Informational (status code class)&nbsp;&nbsp;<a href="#rfc.iref.25"><b>6.2</b></a></li>
    48664865               </ul>
    48674866            </li>
    48684867            <li><a id="rfc.index.2" href="#rfc.index.2"><b>2</b></a><ul>
    4869                   <li>200 OK (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.200.1">6.1</a>, <a href="#rfc.iref.27"><b>6.3.1</b></a>, <a href="#rfc.xref.status.200.2">12.2.3</a></li>
    4870                   <li>201 Created (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.201.1">6.1</a>, <a href="#rfc.iref.28"><b>6.3.2</b></a>, <a href="#rfc.xref.status.201.2">12.2.3</a></li>
    4871                   <li>202 Accepted (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.202.1">6.1</a>, <a href="#rfc.iref.29"><b>6.3.3</b></a>, <a href="#rfc.xref.status.202.2">12.2.3</a></li>
    4872                   <li>203 Non-Authoritative Information (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.203.1">6.1</a>, <a href="#rfc.iref.30"><b>6.3.4</b></a>, <a href="#rfc.xref.status.203.2">12.2.3</a>, <a href="#rfc.xref.status.203.3">C</a></li>
    4873                   <li>204 No Content (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.204.1">6.1</a>, <a href="#rfc.iref.31"><b>6.3.5</b></a>, <a href="#rfc.xref.status.204.2">12.2.3</a></li>
    4874                   <li>205 Reset Content (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.205.1">6.1</a>, <a href="#rfc.iref.32"><b>6.3.6</b></a>, <a href="#rfc.xref.status.205.2">12.2.3</a></li>
    4875                   <li>2xx Successful (status code class)&nbsp;&nbsp;<a href="#rfc.iref.26"><b>6.3</b></a></li>
     4868                  <li>200 OK (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.200.1">6.1</a>, <a href="#rfc.iref.29"><b>6.3.1</b></a>, <a href="#rfc.xref.status.200.2">11.2.3</a></li>
     4869                  <li>201 Created (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.201.1">6.1</a>, <a href="#rfc.iref.30"><b>6.3.2</b></a>, <a href="#rfc.xref.status.201.2">11.2.3</a></li>
     4870                  <li>202 Accepted (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.202.1">6.1</a>, <a href="#rfc.iref.31"><b>6.3.3</b></a>, <a href="#rfc.xref.status.202.2">11.2.3</a></li>
     4871                  <li>203 Non-Authoritative Information (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.203.1">6.1</a>, <a href="#rfc.iref.32"><b>6.3.4</b></a>, <a href="#rfc.xref.status.203.2">11.2.3</a>, <a href="#rfc.xref.status.203.3">C</a></li>
     4872                  <li>204 No Content (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.204.1">6.1</a>, <a href="#rfc.iref.33"><b>6.3.5</b></a>, <a href="#rfc.xref.status.204.2">11.2.3</a></li>
     4873                  <li>205 Reset Content (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.205.1">6.1</a>, <a href="#rfc.iref.34"><b>6.3.6</b></a>, <a href="#rfc.xref.status.205.2">11.2.3</a></li>
     4874                  <li>2xx Successful (status code class)&nbsp;&nbsp;<a href="#rfc.iref.28"><b>6.3</b></a></li>
    48764875               </ul>
    48774876            </li>
    48784877            <li><a id="rfc.index.3" href="#rfc.index.3"><b>3</b></a><ul>
    4879                   <li>300 Multiple Choices (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.300.1">6.1</a>, <a href="#rfc.iref.34"><b>6.4.1</b></a>, <a href="#rfc.xref.status.300.2">12.2.3</a></li>
    4880                   <li>301 Moved Permanently (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.301.1">6.1</a>, <a href="#rfc.iref.35"><b>6.4.2</b></a>, <a href="#rfc.xref.status.301.2">12.2.3</a>, <a href="#rfc.xref.status.301.3">C</a></li>
    4881                   <li>302 Found (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.302.1">6.1</a>, <a href="#rfc.iref.36"><b>6.4.3</b></a>, <a href="#rfc.xref.status.302.2">12.2.3</a>, <a href="#rfc.xref.status.302.3">C</a></li>
    4882                   <li>303 See Other (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.303.1">6.1</a>, <a href="#rfc.iref.37"><b>6.4.4</b></a>, <a href="#rfc.xref.status.303.2">12.2.3</a></li>
    4883                   <li>305 Use Proxy (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.305.1">6.1</a>, <a href="#rfc.iref.38"><b>6.4.5</b></a>, <a href="#rfc.xref.status.305.2">12.2.3</a>, <a href="#rfc.xref.status.305.3">C</a></li>
    4884                   <li>306 (Unused) (status code)&nbsp;&nbsp;<a href="#rfc.iref.39"><b>6.4.6</b></a>, <a href="#rfc.xref.status.306.1">12.2.3</a></li>
    4885                   <li>307 Temporary Redirect (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.307.1">6.1</a>, <a href="#rfc.iref.40"><b>6.4.7</b></a>, <a href="#rfc.xref.status.307.2">12.2.3</a>, <a href="#rfc.xref.status.307.3">C</a></li>
    4886                   <li>3xx Redirection (status code class)&nbsp;&nbsp;<a href="#rfc.iref.33"><b>6.4</b></a>, <a href="#rfc.xref.status.3xx.1">C</a></li>
     4878                  <li>300 Multiple Choices (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.300.1">6.1</a>, <a href="#rfc.iref.36"><b>6.4.1</b></a>, <a href="#rfc.xref.status.300.2">11.2.3</a></li>
     4879                  <li>301 Moved Permanently (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.301.1">6.1</a>, <a href="#rfc.iref.37"><b>6.4.2</b></a>, <a href="#rfc.xref.status.301.2">11.2.3</a>, <a href="#rfc.xref.status.301.3">C</a></li>
     4880                  <li>302 Found (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.302.1">6.1</a>, <a href="#rfc.iref.38"><b>6.4.3</b></a>, <a href="#rfc.xref.status.302.2">11.2.3</a>, <a href="#rfc.xref.status.302.3">C</a></li>
     4881                  <li>303 See Other (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.303.1">6.1</a>, <a href="#rfc.iref.39"><b>6.4.4</b></a>, <a href="#rfc.xref.status.303.2">11.2.3</a></li>
     4882                  <li>305 Use Proxy (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.305.1">6.1</a>, <a href="#rfc.iref.40"><b>6.4.5</b></a>, <a href="#rfc.xref.status.305.2">11.2.3</a>, <a href="#rfc.xref.status.305.3">C</a></li>
     4883                  <li>306 (Unused) (status code)&nbsp;&nbsp;<a href="#rfc.iref.41"><b>6.4.6</b></a>, <a href="#rfc.xref.status.306.1">11.2.3</a></li>
     4884                  <li>307 Temporary Redirect (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.307.1">6.1</a>, <a href="#rfc.iref.42"><b>6.4.7</b></a>, <a href="#rfc.xref.status.307.2">11.2.3</a>, <a href="#rfc.xref.status.307.3">C</a></li>
     4885                  <li>3xx Redirection (status code class)&nbsp;&nbsp;<a href="#rfc.iref.35"><b>6.4</b></a>, <a href="#rfc.xref.status.3xx.1">C</a></li>
    48874886               </ul>
    48884887            </li>
    48894888            <li><a id="rfc.index.4" href="#rfc.index.4"><b>4</b></a><ul>
    4890                   <li>400 Bad Request (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.400.1">6.1</a>, <a href="#rfc.iref.42"><b>6.5.1</b></a>, <a href="#rfc.xref.status.400.2">12.2.3</a></li>
    4891                   <li>402 Payment Required (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.402.1">6.1</a>, <a href="#rfc.iref.43"><b>6.5.2</b></a>, <a href="#rfc.xref.status.402.2">12.2.3</a></li>
    4892                   <li>403 Forbidden (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.403.1">6.1</a>, <a href="#rfc.iref.44"><b>6.5.3</b></a>, <a href="#rfc.xref.status.403.2">12.2.3</a></li>
    4893                   <li>404 Not Found (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.404.1">6.1</a>, <a href="#rfc.iref.45"><b>6.5.4</b></a>, <a href="#rfc.xref.status.404.2">12.2.3</a></li>
    4894                   <li>405 Method Not Allowed (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.405.1">6.1</a>, <a href="#rfc.iref.46"><b>6.5.5</b></a>, <a href="#rfc.xref.status.405.2">12.2.3</a></li>
    4895                   <li>406 Not Acceptable (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.406.1">6.1</a>, <a href="#rfc.iref.47"><b>6.5.6</b></a>, <a href="#rfc.xref.status.406.2">12.2.3</a></li>
    4896                   <li>408 Request Timeout (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.408.1">6.1</a>, <a href="#rfc.iref.48"><b>6.5.7</b></a>, <a href="#rfc.xref.status.408.2">12.2.3</a></li>
    4897                   <li>409 Conflict (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.409.1">6.1</a>, <a href="#rfc.iref.49"><b>6.5.8</b></a>, <a href="#rfc.xref.status.409.2">12.2.3</a></li>
    4898                   <li>410 Gone (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.410.1">6.1</a>, <a href="#rfc.iref.50"><b>6.5.9</b></a>, <a href="#rfc.xref.status.410.2">12.2.3</a></li>
    4899                   <li>411 Length Required (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.411.1">6.1</a>, <a href="#rfc.iref.51"><b>6.5.10</b></a>, <a href="#rfc.xref.status.411.2">12.2.3</a></li>
    4900                   <li>413 Request Representation Too Large (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.413.1">6.1</a>, <a href="#rfc.iref.52"><b>6.5.11</b></a>, <a href="#rfc.xref.status.413.2">12.2.3</a></li>
    4901                   <li>414 URI Too Long (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.414.1">6.1</a>, <a href="#rfc.iref.53"><b>6.5.12</b></a>, <a href="#rfc.xref.status.414.2">12.2.3</a></li>
    4902                   <li>415 Unsupported Media Type (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.415.1">6.1</a>, <a href="#rfc.iref.54"><b>6.5.13</b></a>, <a href="#rfc.xref.status.415.2">12.2.3</a></li>
    4903                   <li>417 Expectation Failed (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.417.1">6.1</a>, <a href="#rfc.iref.55"><b>6.5.14</b></a>, <a href="#rfc.xref.status.417.2">12.2.3</a></li>
    4904                   <li>426 Upgrade Required (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.426.1">6.1</a>, <a href="#rfc.iref.56"><b>6.5.15</b></a>, <a href="#rfc.xref.status.426.2">12.2.3</a>, <a href="#rfc.xref.status.426.3">C</a></li>
    4905                   <li>4xx Client Error (status code class)&nbsp;&nbsp;<a href="#rfc.iref.41"><b>6.5</b></a></li>
     4889                  <li>400 Bad Request (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.400.1">6.1</a>, <a href="#rfc.iref.44"><b>6.5.1</b></a>, <a href="#rfc.xref.status.400.2">11.2.3</a></li>
     4890                  <li>402 Payment Required (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.402.1">6.1</a>, <a href="#rfc.iref.45"><b>6.5.2</b></a>, <a href="#rfc.xref.status.402.2">11.2.3</a></li>
     4891                  <li>403 Forbidden (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.403.1">6.1</a>, <a href="#rfc.iref.46"><b>6.5.3</b></a>, <a href="#rfc.xref.status.403.2">11.2.3</a></li>
     4892                  <li>404 Not Found (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.404.1">6.1</a>, <a href="#rfc.iref.47"><b>6.5.4</b></a>, <a href="#rfc.xref.status.404.2">11.2.3</a></li>
     4893                  <li>405 Method Not Allowed (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.405.1">6.1</a>, <a href="#rfc.iref.48"><b>6.5.5</b></a>, <a href="#rfc.xref.status.405.2">11.2.3</a></li>
     4894                  <li>406 Not Acceptable (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.406.1">6.1</a>, <a href="#rfc.iref.49"><b>6.5.6</b></a>, <a href="#rfc.xref.status.406.2">11.2.3</a></li>
     4895                  <li>408 Request Timeout (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.408.1">6.1</a>, <a href="#rfc.iref.50"><b>6.5.7</b></a>, <a href="#rfc.xref.status.408.2">11.2.3</a></li>
     4896                  <li>409 Conflict (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.409.1">6.1</a>, <a href="#rfc.iref.51"><b>6.5.8</b></a>, <a href="#rfc.xref.status.409.2">11.2.3</a></li>
     4897                  <li>410 Gone (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.410.1">6.1</a>, <a href="#rfc.iref.52"><b>6.5.9</b></a>, <a href="#rfc.xref.status.410.2">11.2.3</a></li>
     4898                  <li>411 Length Required (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.411.1">6.1</a>, <a href="#rfc.iref.53"><b>6.5.10</b></a>, <a href="#rfc.xref.status.411.2">11.2.3</a></li>
     4899                  <li>413 Request Representation Too Large (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.413.1">6.1</a>, <a href="#rfc.iref.54"><b>6.5.11</b></a>, <a href="#rfc.xref.status.413.2">11.2.3</a></li>
     4900                  <li>414 URI Too Long (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.414.1">6.1</a>, <a href="#rfc.iref.55"><b>6.5.12</b></a>, <a href="#rfc.xref.status.414.2">11.2.3</a></li>
     4901                  <li>415 Unsupported Media Type (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.415.1">6.1</a>, <a href="#rfc.iref.56"><b>6.5.13</b></a>, <a href="#rfc.xref.status.415.2">11.2.3</a></li>
     4902                  <li>417 Expectation Failed (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.417.1">6.1</a>, <a href="#rfc.iref.57"><b>6.5.14</b></a>, <a href="#rfc.xref.status.417.2">11.2.3</a></li>
     4903                  <li>426 Upgrade Required (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.426.1">6.1</a>, <a href="#rfc.iref.58"><b>6.5.15</b></a>, <a href="#rfc.xref.status.426.2">11.2.3</a>, <a href="#rfc.xref.status.426.3">C</a></li>
     4904                  <li>4xx Client Error (status code class)&nbsp;&nbsp;<a href="#rfc.iref.43"><b>6.5</b></a></li>
    49064905               </ul>
    49074906            </li>
    49084907            <li><a id="rfc.index.5" href="#rfc.index.5"><b>5</b></a><ul>
    4909                   <li>500 Internal Server Error (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.500.1">6.1</a>, <a href="#rfc.iref.58"><b>6.6.1</b></a>, <a href="#rfc.xref.status.500.2">12.2.3</a></li>
    4910                   <li>501 Not Implemented (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.501.1">6.1</a>, <a href="#rfc.iref.59"><b>6.6.2</b></a>, <a href="#rfc.xref.status.501.2">12.2.3</a></li>
    4911                   <li>502 Bad Gateway (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.502.1">6.1</a>, <a href="#rfc.iref.60"><b>6.6.3</b></a>, <a href="#rfc.xref.status.502.2">12.2.3</a></li>
    4912                   <li>503 Service Unavailable (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.503.1">6.1</a>, <a href="#rfc.iref.61"><b>6.6.4</b></a>, <a href="#rfc.xref.status.503.2">12.2.3</a></li>
    4913                   <li>504 Gateway Timeout (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.504.1">6.1</a>, <a href="#rfc.iref.62"><b>6.6.5</b></a>, <a href="#rfc.xref.status.504.2">12.2.3</a></li>
    4914                   <li>505 HTTP Version Not Supported (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.505.1">6.1</a>, <a href="#rfc.iref.63"><b>6.6.6</b></a>, <a href="#rfc.xref.status.505.2">12.2.3</a></li>
    4915                   <li>5xx Server Error (status code class)&nbsp;&nbsp;<a href="#rfc.iref.57"><b>6.6</b></a></li>
     4908                  <li>500 Internal Server Error (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.500.1">6.1</a>, <a href="#rfc.iref.60"><b>6.6.1</b></a>, <a href="#rfc.xref.status.500.2">11.2.3</a></li>
     4909                  <li>501 Not Implemented (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.501.1">6.1</a>, <a href="#rfc.iref.61"><b>6.6.2</b></a>, <a href="#rfc.xref.status.501.2">11.2.3</a></li>
     4910                  <li>502 Bad Gateway (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.502.1">6.1</a>, <a href="#rfc.iref.62"><b>6.6.3</b></a>, <a href="#rfc.xref.status.502.2">11.2.3</a></li>
     4911                  <li>503 Service Unavailable (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.503.1">6.1</a>, <a href="#rfc.iref.63"><b>6.6.4</b></a>, <a href="#rfc.xref.status.503.2">11.2.3</a></li>
     4912                  <li>504 Gateway Timeout (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.504.1">6.1</a>, <a href="#rfc.iref.64"><b>6.6.5</b></a>, <a href="#rfc.xref.status.504.2">11.2.3</a></li>
     4913                  <li>505 HTTP Version Not Supported (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.505.1">6.1</a>, <a href="#rfc.iref.65"><b>6.6.6</b></a>, <a href="#rfc.xref.status.505.2">11.2.3</a></li>
     4914                  <li>5xx Server Error (status code class)&nbsp;&nbsp;<a href="#rfc.iref.59"><b>6.6</b></a></li>
    49164915               </ul>
    49174916            </li>
    49184917            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
    4919                   <li>Accept header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">5.3</a>, <a href="#rfc.xref.header.accept.2">8.5</a>, <a href="#rfc.xref.header.accept.3">10.1</a>, <a href="#rfc.iref.a.1"><b>11.1</b></a>, <a href="#rfc.xref.header.accept.4">12.3.2</a></li>
    4920                   <li>Accept-Charset header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">5.3</a>, <a href="#rfc.xref.header.accept-charset.2">10.1</a>, <a href="#rfc.iref.a.2"><b>11.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">12.3.2</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>
    4921                   <li>Accept-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">5.3</a>, <a href="#rfc.xref.header.accept-encoding.2">8.4</a>, <a href="#rfc.xref.header.accept-encoding.3">10.1</a>, <a href="#rfc.iref.a.3"><b>11.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">12.3.2</a>, <a href="#rfc.xref.header.accept-encoding.5">12.4.2</a></li>
    4922                   <li>Accept-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">5.3</a>, <a href="#rfc.xref.header.accept-language.2">10.1</a>, <a href="#rfc.iref.a.4"><b>11.4</b></a>, <a href="#rfc.xref.header.accept-language.3">12.3.2</a></li>
    4923                   <li>Allow header field&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">4.1</a>, <a href="#rfc.xref.header.allow.2">7</a>, <a href="#rfc.iref.a.5"><b>11.5</b></a>, <a href="#rfc.xref.header.allow.3">12.3.2</a>, <a href="#rfc.xref.header.allow.4">C</a></li>
     4918                  <li>Accept header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">3.4.1</a>, <a href="#rfc.xref.header.accept.2">5.3</a>, <a href="#rfc.xref.header.accept.3">8.5</a>, <a href="#rfc.iref.a.1"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3.2</a></li>
     4919                  <li>Accept-Charset header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">3.4.1</a>, <a href="#rfc.xref.header.accept-charset.2">5.3</a>, <a href="#rfc.iref.a.2"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3.2</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>
     4920                  <li>Accept-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">3.4.1</a>, <a href="#rfc.xref.header.accept-encoding.2">5.3</a>, <a href="#rfc.xref.header.accept-encoding.3">8.4</a>, <a href="#rfc.iref.a.3"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3.2</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li>
     4921                  <li>Accept-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">3.4.1</a>, <a href="#rfc.xref.header.accept-language.2">5.3</a>, <a href="#rfc.iref.a.4"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3.2</a></li>
     4922                  <li>Allow header field&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">4.1</a>, <a href="#rfc.xref.header.allow.2">7</a>, <a href="#rfc.iref.a.5"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3.2</a>, <a href="#rfc.xref.header.allow.4">C</a></li>
    49244923               </ul>
    49254924            </li>
    … …  
    49344933                  </li>
    49354934                  <li>compress (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.c.4">8.4</a></li>
    4936                   <li>CONNECT method&nbsp;&nbsp;<a href="#rfc.xref.CONNECT.1">4.1</a>, <a href="#rfc.iref.c.3"><b>4.3.6</b></a>, <a href="#rfc.xref.CONNECT.2">12.1.3</a>, <a href="#rfc.xref.CONNECT.3">C</a></li>
     4935                  <li>CONNECT method&nbsp;&nbsp;<a href="#rfc.xref.CONNECT.1">4.1</a>, <a href="#rfc.iref.c.3"><b>4.3.6</b></a>, <a href="#rfc.xref.CONNECT.2">11.1.3</a>, <a href="#rfc.xref.CONNECT.3">C</a></li>
    49374936                  <li>content negotiation&nbsp;&nbsp;<a href="#rfc.iref.c.1">1</a></li>
    4938                   <li>Content-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">3.2</a>, <a href="#rfc.xref.header.content-encoding.2">8.4</a>, <a href="#rfc.iref.c.8"><b>11.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">12.3.2</a></li>
    4939                   <li>Content-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">3.2</a>, <a href="#rfc.iref.c.9"><b>11.7</b></a>, <a href="#rfc.xref.header.content-language.2">12.3.2</a></li>
    4940                   <li>Content-Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.2</a>, <a href="#rfc.xref.header.content-location.2">4.3.3</a>, <a href="#rfc.iref.c.10"><b>11.8</b></a>, <a href="#rfc.xref.header.content-location.3">11.13</a>, <a href="#rfc.xref.header.content-location.4">12.3.2</a>, <a href="#rfc.xref.header.content-location.5">C</a></li>
     4937                  <li>Content-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">3.2</a>, <a href="#rfc.xref.header.content-encoding.2">8.4</a>, <a href="#rfc.iref.c.8"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3.2</a></li>
     4938                  <li>Content-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">3.2</a>, <a href="#rfc.iref.c.9"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3.2</a></li>
     4939                  <li>Content-Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.2</a>, <a href="#rfc.xref.header.content-location.2">4.3.3</a>, <a href="#rfc.iref.c.10"><b>10.8</b></a>, <a href="#rfc.xref.header.content-location.3">10.13</a>, <a href="#rfc.xref.header.content-location.4">11.3.2</a>, <a href="#rfc.xref.header.content-location.5">C</a></li>
    49414940                  <li>Content-Transfer-Encoding header field&nbsp;&nbsp;<a href="#rfc.iref.c.12">A.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">C</a></li>
    4942                   <li>Content-Type header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">3.2</a>, <a href="#rfc.xref.header.content-type.2">6</a>, <a href="#rfc.xref.header.content-type.3">8.5</a>, <a href="#rfc.iref.c.11"><b>11.9</b></a>, <a href="#rfc.xref.header.content-type.4">12.3.1</a>, <a href="#rfc.xref.header.content-type.5">12.3.2</a></li>
     4941                  <li>Content-Type header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">3.2</a>, <a href="#rfc.xref.header.content-type.2">6</a>, <a href="#rfc.xref.header.content-type.3">8.5</a>, <a href="#rfc.iref.c.11"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.4">11.3.1</a>, <a href="#rfc.xref.header.content-type.5">11.3.2</a></li>
    49434942               </ul>
    49444943            </li>
    49454944            <li><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul>
    4946                   <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">7</a>, <a href="#rfc.iref.d.3"><b>11.10</b></a>, <a href="#rfc.xref.header.date.2">12.3.2</a></li>
     4945                  <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">7</a>, <a href="#rfc.iref.d.3"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3.2</a></li>
    49474946                  <li>deflate (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.d.2">8.4</a></li>
    4948                   <li>DELETE method&nbsp;&nbsp;<a href="#rfc.xref.DELETE.1">4.1</a>, <a href="#rfc.iref.d.1"><b>4.3.5</b></a>, <a href="#rfc.xref.DELETE.2">12.1.3</a></li>
     4947                  <li>DELETE method&nbsp;&nbsp;<a href="#rfc.xref.DELETE.1">4.1</a>, <a href="#rfc.iref.d.1"><b>4.3.5</b></a>, <a href="#rfc.xref.DELETE.2">11.1.3</a></li>
    49494948               </ul>
    49504949            </li>
    49514950            <li><a id="rfc.index.E" href="#rfc.index.E"><b>E</b></a><ul>
    4952                   <li>Expect header field&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">5.1</a>, <a href="#rfc.xref.header.expect.2">6.5.14</a>, <a href="#rfc.iref.e.1"><b>11.11</b></a>, <a href="#rfc.xref.header.expect.3">12.3.2</a>, <a href="#rfc.xref.header.expect.4">C</a></li>
     4951                  <li>Expect header field&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">5.1</a>, <a href="#rfc.xref.header.expect.2">6.5.14</a>, <a href="#rfc.iref.e.1"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3.2</a>, <a href="#rfc.xref.header.expect.4">C</a></li>
    49534952                  <li>Expect Values&nbsp;&nbsp;
    49544953                     <ul>
    4955                         <li>100-continue&nbsp;&nbsp;<a href="#rfc.iref.e.2"><b>11.11</b></a></li>
     4954                        <li>100-continue&nbsp;&nbsp;<a href="#rfc.iref.e.2"><b>10.11</b></a></li>
    49564955                     </ul>
    49574956                  </li>
    … …  
    49594958            </li>
    49604959            <li><a id="rfc.index.F" href="#rfc.index.F"><b>F</b></a><ul>
    4961                   <li>From header field&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">5.5</a>, <a href="#rfc.iref.f.1"><b>11.12</b></a>, <a href="#rfc.xref.header.from.2">12.3.2</a></li>
     4960                  <li>From header field&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">5.5</a>, <a href="#rfc.iref.f.1"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3.2</a></li>
    49624961               </ul>
    49634962            </li>
    49644963            <li><a id="rfc.index.G" href="#rfc.index.G"><b>G</b></a><ul>
    4965                   <li>GET method&nbsp;&nbsp;<a href="#rfc.xref.GET.1">4.1</a>, <a href="#rfc.iref.g.2"><b>4.3.1</b></a>, <a href="#rfc.xref.GET.2">12.1.3</a></li>
     4964                  <li>GET method&nbsp;&nbsp;<a href="#rfc.xref.GET.1">4.1</a>, <a href="#rfc.iref.g.4"><b>4.3.1</b></a>, <a href="#rfc.xref.GET.2">11.1.3</a></li>
    49664965                  <li><tt>Grammar</tt>&nbsp;&nbsp;
    49674966                     <ul>
    4968                         <li><tt>Accept</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.33"><b>11.1</b></a></li>
    4969                         <li><tt>Accept-Charset</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.37"><b>11.2</b></a></li>
    4970                         <li><tt>Accept-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.38"><b>11.3</b></a></li>
    4971                         <li><tt>accept-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.36"><b>11.1</b></a></li>
    4972                         <li><tt>Accept-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.40"><b>11.4</b></a></li>
    4973                         <li><tt>accept-params</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.35"><b>11.1</b></a></li>
    4974                         <li><tt>Allow</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.42"><b>11.5</b></a></li>
    4975                         <li><tt>asctime-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.18"><b>8.1</b></a></li>
    4976                         <li><tt>attribute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.28"><b>8.5</b></a></li>
    4977                         <li><tt>charset</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.21"><b>8.3</b></a></li>
    4978                         <li><tt>codings</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.39"><b>11.3</b></a></li>
    4979                         <li><tt>content-coding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.22"><b>8.4</b></a></li>
    4980                         <li><tt>Content-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.43"><b>11.6</b></a></li>
    4981                         <li><tt>Content-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.44"><b>11.7</b></a></li>
    4982                         <li><tt>Content-Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.45"><b>11.8</b></a></li>
    4983                         <li><tt>Content-Type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.46"><b>11.9</b></a></li>
    4984                         <li><tt>Date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.47"><b>11.10</b></a></li>
    4985                         <li><tt>date1</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>8.1</b></a></li>
    4986                         <li><tt>day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.12"><b>8.1</b></a></li>
    4987                         <li><tt>day-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>8.1</b></a></li>
    4988                         <li><tt>day-name-l</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.11"><b>8.1</b></a></li>
    4989                         <li><tt>delta-seconds</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.58"><b>11.16</b></a></li>
    4990                         <li><tt>Expect</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.48"><b>11.11</b></a></li>
    4991                         <li><tt>expect-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.52"><b>11.11</b></a></li>
    4992                         <li><tt>expect-param</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.50"><b>11.11</b></a></li>
    4993                         <li><tt>expect-value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.51"><b>11.11</b></a></li>
    4994                         <li><tt>expectation</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.49"><b>11.11</b></a></li>
    4995                         <li><tt>From</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.53"><b>11.12</b></a></li>
    4996                         <li><tt>GMT</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.15"><b>8.1</b></a></li>
    4997                         <li><tt>hour</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>8.1</b></a></li>
    4998                         <li><tt>HTTP-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>8.1</b></a></li>
    4999                         <li><tt>language-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.41"><b>11.4</b></a></li>
    5000                         <li><tt>language-tag</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.30"><b>8.6</b></a></li>
    5001                         <li><tt>Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.54"><b>11.13</b></a></li>
    5002                         <li><tt>Max-Forwards</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.55"><b>11.14</b></a></li>
    5003                         <li><tt>media-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.34"><b>11.1</b></a></li>
    5004                         <li><tt>media-type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.24"><b>8.5</b></a></li>
    5005                         <li><tt>method</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>4.1</b></a></li>
     4967                        <li><tt>Accept</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.33"><b>10.1</b></a></li>
     4968                        <li><tt>Accept-Charset</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.37"><b>10.2</b></a></li>
     4969                        <li><tt>Accept-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.38"><b>10.3</b></a></li>
     4970                        <li><tt>accept-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.36"><b>10.1</b></a></li>
     4971                        <li><tt>Accept-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.40"><b>10.4</b></a></li>
     4972                        <li><tt>accept-params</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.35"><b>10.1</b></a></li>
     4973                        <li><tt>Allow</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.42"><b>10.5</b></a></li>
     4974                        <li><tt>asctime-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.20"><b>8.1</b></a></li>
     4975                        <li><tt>attribute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.30"><b>8.5</b></a></li>
     4976                        <li><tt>charset</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.23"><b>8.3</b></a></li>
     4977                        <li><tt>codings</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.39"><b>10.3</b></a></li>
     4978                        <li><tt>content-coding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.24"><b>8.4</b></a></li>
     4979                        <li><tt>Content-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.43"><b>10.6</b></a></li>
     4980                        <li><tt>Content-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.44"><b>10.7</b></a></li>
     4981                        <li><tt>Content-Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.45"><b>10.8</b></a></li>
     4982                        <li><tt>Content-Type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.46"><b>10.9</b></a></li>
     4983                        <li><tt>Date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.47"><b>10.10</b></a></li>
     4984                        <li><tt>date1</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>8.1</b></a></li>
     4985                        <li><tt>day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.14"><b>8.1</b></a></li>
     4986                        <li><tt>day-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.12"><b>8.1</b></a></li>
     4987                        <li><tt>day-name-l</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.13"><b>8.1</b></a></li>
     4988                        <li><tt>delta-seconds</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.58"><b>10.16</b></a></li>
     4989                        <li><tt>Expect</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.48"><b>10.11</b></a></li>
     4990                        <li><tt>expect-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.52"><b>10.11</b></a></li>
     4991                        <li><tt>expect-param</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.50"><b>10.11</b></a></li>
     4992                        <li><tt>expect-value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.51"><b>10.11</b></a></li>
     4993                        <li><tt>expectation</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.49"><b>10.11</b></a></li>
     4994                        <li><tt>From</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.53"><b>10.12</b></a></li>
     4995                        <li><tt>GMT</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.17"><b>8.1</b></a></li>
     4996                        <li><tt>hour</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>8.1</b></a></li>
     4997                        <li><tt>HTTP-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>8.1</b></a></li>
     4998                        <li><tt>language-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.41"><b>10.4</b></a></li>
     4999                        <li><tt>language-tag</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.32"><b>8.6</b></a></li>
     5000                        <li><tt>Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.54"><b>10.13</b></a></li>
     5001                        <li><tt>Max-Forwards</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.55"><b>10.14</b></a></li>
     5002                        <li><tt>media-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.34"><b>10.1</b></a></li>
     5003                        <li><tt>media-type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.26"><b>8.5</b></a></li>
     5004                        <li><tt>method</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>4.1</b></a></li>
    50065005                        <li><tt>MIME-Version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.61"><b>A.1</b></a></li>
    5007                         <li><tt>minute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>8.1</b></a></li>
    5008                         <li><tt>month</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.13"><b>8.1</b></a></li>
    5009                         <li><tt>obs-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.16"><b>8.1</b></a></li>
    5010                         <li><tt>parameter</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.27"><b>8.5</b></a></li>
    5011                         <li><tt>product</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.19"><b>8.2</b></a></li>
    5012                         <li><tt>product-version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.20"><b>8.2</b></a></li>
    5013                         <li><tt>qvalue</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.32"><b>10.3</b></a></li>
    5014                         <li><tt>Referer</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.56"><b>11.15</b></a></li>
    5015                         <li><tt>Retry-After</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.57"><b>11.16</b></a></li>
    5016                         <li><tt>rfc1123-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.4"><b>8.1</b></a></li>
    5017                         <li><tt>rfc850-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.17"><b>8.1</b></a></li>
    5018                         <li><tt>second</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>8.1</b></a></li>
    5019                         <li><tt>Server</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.59"><b>11.17</b></a></li>
    5020                         <li><tt>subtype</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.26"><b>8.5</b></a></li>
    5021                         <li><tt>time-of-day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>8.1</b></a></li>
    5022                         <li><tt>type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.25"><b>8.5</b></a></li>
    5023                         <li><tt>User-Agent</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.60"><b>11.18</b></a></li>
    5024                         <li><tt>value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.29"><b>8.5</b></a></li>
    5025                         <li><tt>weight</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.31"><b>10.3</b></a></li>
    5026                         <li><tt>year</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.14"><b>8.1</b></a></li>
     5006                        <li><tt>minute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>8.1</b></a></li>
     5007                        <li><tt>month</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.15"><b>8.1</b></a></li>
     5008                        <li><tt>obs-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.18"><b>8.1</b></a></li>
     5009                        <li><tt>parameter</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.29"><b>8.5</b></a></li>
     5010                        <li><tt>product</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.21"><b>8.2</b></a></li>
     5011                        <li><tt>product-version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.22"><b>8.2</b></a></li>
     5012                        <li><tt>qvalue</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.2"><b>3.4.3</b></a></li>
     5013                        <li><tt>Referer</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.56"><b>10.15</b></a></li>
     5014                        <li><tt>Retry-After</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.57"><b>10.16</b></a></li>
     5015                        <li><tt>rfc1123-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>8.1</b></a></li>
     5016                        <li><tt>rfc850-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.19"><b>8.1</b></a></li>
     5017                        <li><tt>second</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.11"><b>8.1</b></a></li>
     5018                        <li><tt>Server</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.59"><b>10.17</b></a></li>
     5019                        <li><tt>subtype</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.28"><b>8.5</b></a></li>
     5020                        <li><tt>time-of-day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>8.1</b></a></li>
     5021                        <li><tt>type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.27"><b>8.5</b></a></li>
     5022                        <li><tt>User-Agent</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.60"><b>10.18</b></a></li>
     5023                        <li><tt>value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.31"><b>8.5</b></a></li>
     5024                        <li><tt>weight</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>3.4.3</b></a></li>
     5025                        <li><tt>year</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.16"><b>8.1</b></a></li>
    50275026                     </ul>
    50285027                  </li>
    5029                   <li>gzip (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.g.23">8.4</a></li>
     5028                  <li>gzip (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.g.25">8.4</a></li>
    50305029               </ul>
    50315030            </li>
    50325031            <li><a id="rfc.index.H" href="#rfc.index.H"><b>H</b></a><ul>
    5033                   <li>HEAD method&nbsp;&nbsp;<a href="#rfc.xref.HEAD.1">4.1</a>, <a href="#rfc.iref.h.1"><b>4.3.2</b></a>, <a href="#rfc.xref.HEAD.2">12.1.3</a></li>
     5032                  <li>HEAD method&nbsp;&nbsp;<a href="#rfc.xref.HEAD.1">4.1</a>, <a href="#rfc.iref.h.1"><b>4.3.2</b></a>, <a href="#rfc.xref.HEAD.2">11.1.3</a></li>
    50345033                  <li>Header Fields&nbsp;&nbsp;
    50355034                     <ul>
    5036                         <li>Accept&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">5.3</a>, <a href="#rfc.xref.header.accept.2">8.5</a>, <a href="#rfc.xref.header.accept.3">10.1</a>, <a href="#rfc.iref.h.2"><b>11.1</b></a>, <a href="#rfc.xref.header.accept.4">12.3.2</a></li>
    5037                         <li>Accept-Charset&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">5.3</a>, <a href="#rfc.xref.header.accept-charset.2">10.1</a>, <a href="#rfc.iref.h.3"><b>11.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">12.3.2</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>
    5038                         <li>Accept-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">5.3</a>, <a href="#rfc.xref.header.accept-encoding.2">8.4</a>, <a href="#rfc.xref.header.accept-encoding.3">10.1</a>, <a href="#rfc.iref.h.4"><b>11.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">12.3.2</a>, <a href="#rfc.xref.header.accept-encoding.5">12.4.2</a></li>
    5039                         <li>Accept-Language&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">5.3</a>, <a href="#rfc.xref.header.accept-language.2">10.1</a>, <a href="#rfc.iref.h.5"><b>11.4</b></a>, <a href="#rfc.xref.header.accept-language.3">12.3.2</a></li>
    5040                         <li>Allow&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">4.1</a>, <a href="#rfc.xref.header.allow.2">7</a>, <a href="#rfc.iref.h.6"><b>11.5</b></a>, <a href="#rfc.xref.header.allow.3">12.3.2</a>, <a href="#rfc.xref.header.allow.4">C</a></li>
    5041                         <li>Content-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">3.2</a>, <a href="#rfc.xref.header.content-encoding.2">8.4</a>, <a href="#rfc.iref.h.7"><b>11.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">12.3.2</a></li>
    5042                         <li>Content-Language&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">3.2</a>, <a href="#rfc.iref.h.8"><b>11.7</b></a>, <a href="#rfc.xref.header.content-language.2">12.3.2</a></li>
    5043                         <li>Content-Location&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.2</a>, <a href="#rfc.xref.header.content-location.2">4.3.3</a>, <a href="#rfc.iref.h.9"><b>11.8</b></a>, <a href="#rfc.xref.header.content-location.3">11.13</a>, <a href="#rfc.xref.header.content-location.4">12.3.2</a>, <a href="#rfc.xref.header.content-location.5">C</a></li>
     5035                        <li>Accept&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">3.4.1</a>, <a href="#rfc.xref.header.accept.2">5.3</a>, <a href="#rfc.xref.header.accept.3">8.5</a>, <a href="#rfc.iref.h.2"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3.2</a></li>
     5036                        <li>Accept-Charset&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">3.4.1</a>, <a href="#rfc.xref.header.accept-charset.2">5.3</a>, <a href="#rfc.iref.h.3"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3.2</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>
     5037                        <li>Accept-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">3.4.1</a>, <a href="#rfc.xref.header.accept-encoding.2">5.3</a>, <a href="#rfc.xref.header.accept-encoding.3">8.4</a>, <a href="#rfc.iref.h.4"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3.2</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li>
     5038                        <li>Accept-Language&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">3.4.1</a>, <a href="#rfc.xref.header.accept-language.2">5.3</a>, <a href="#rfc.iref.h.5"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3.2</a></li>
     5039                        <li>Allow&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">4.1</a>, <a href="#rfc.xref.header.allow.2">7</a>, <a href="#rfc.iref.h.6"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3.2</a>, <a href="#rfc.xref.header.allow.4">C</a></li>
     5040                        <li>Content-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">3.2</a>, <a href="#rfc.xref.header.content-encoding.2">8.4</a>, <a href="#rfc.iref.h.7"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3.2</a></li>
     5041                        <li>Content-Language&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">3.2</a>, <a href="#rfc.iref.h.8"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3.2</a></li>
     5042                        <li>Content-Location&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.2</a>, <a href="#rfc.xref.header.content-location.2">4.3.3</a>, <a href="#rfc.iref.h.9"><b>10.8</b></a>, <a href="#rfc.xref.header.content-location.3">10.13</a>, <a href="#rfc.xref.header.content-location.4">11.3.2</a>, <a href="#rfc.xref.header.content-location.5">C</a></li>
    50445043                        <li>Content-Transfer-Encoding&nbsp;&nbsp;<a href="#rfc.iref.h.21">A.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">C</a></li>
    5045                         <li>Content-Type&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">3.2</a>, <a href="#rfc.xref.header.content-type.2">6</a>, <a href="#rfc.xref.header.content-type.3">8.5</a>, <a href="#rfc.iref.h.10"><b>11.9</b></a>, <a href="#rfc.xref.header.content-type.4">12.3.1</a>, <a href="#rfc.xref.header.content-type.5">12.3.2</a></li>
    5046                         <li>Date&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">7</a>, <a href="#rfc.iref.h.11"><b>11.10</b></a>, <a href="#rfc.xref.header.date.2">12.3.2</a></li>
    5047                         <li>Expect&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">5.1</a>, <a href="#rfc.xref.header.expect.2">6.5.14</a>, <a href="#rfc.iref.h.12"><b>11.11</b></a>, <a href="#rfc.xref.header.expect.3">12.3.2</a>, <a href="#rfc.xref.header.expect.4">C</a></li>
    5048                         <li>From&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">5.5</a>, <a href="#rfc.iref.h.13"><b>11.12</b></a>, <a href="#rfc.xref.header.from.2">12.3.2</a></li>
    5049                         <li>Location&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">4.3.3</a>, <a href="#rfc.xref.header.location.2">6.4</a>, <a href="#rfc.xref.header.location.3">7</a>, <a href="#rfc.iref.h.14"><b>11.13</b></a>, <a href="#rfc.xref.header.location.4">12.3.2</a>, <a href="#rfc.xref.header.location.5">C</a></li>
    5050                         <li>Max-Forwards&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">4.3.7</a>, <a href="#rfc.xref.header.max-forwards.2">4.3.8</a>, <a href="#rfc.xref.header.max-forwards.3">5.1</a>, <a href="#rfc.iref.h.15"><b>11.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">12.3.2</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>
    5051                         <li>MIME-Version&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">12.3.2</a>, <a href="#rfc.iref.h.20"><b>A.1</b></a></li>
    5052                         <li>Referer&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">5.5</a>, <a href="#rfc.iref.h.16"><b>11.15</b></a>, <a href="#rfc.xref.header.referer.2">12.3.2</a>, <a href="#rfc.xref.header.referer.3">C</a></li>
    5053                         <li>Retry-After&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">6.6.4</a>, <a href="#rfc.xref.header.retry-after.2">7</a>, <a href="#rfc.iref.h.17"><b>11.16</b></a>, <a href="#rfc.xref.header.retry-after.3">12.3.2</a></li>
    5054                         <li>Server&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">7</a>, <a href="#rfc.iref.h.18"><b>11.17</b></a>, <a href="#rfc.xref.header.server.2">12.3.2</a>, <a href="#rfc.xref.header.server.3">13.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>
    5055                         <li>User-Agent&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">5.5</a>, <a href="#rfc.xref.header.user-agent.2">10.1</a>, <a href="#rfc.iref.h.19"><b>11.18</b></a>, <a href="#rfc.xref.header.user-agent.3">12.3.2</a>, <a href="#rfc.xref.header.user-agent.4">13.1</a></li>
     5044                        <li>Content-Type&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">3.2</a>, <a href="#rfc.xref.header.content-type.2">6</a>, <a href="#rfc.xref.header.content-type.3">8.5</a>, <a href="#rfc.iref.h.10"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.4">11.3.1</a>, <a href="#rfc.xref.header.content-type.5">11.3.2</a></li>
     5045                        <li>Date&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">7</a>, <a href="#rfc.iref.h.11"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3.2</a></li>
     5046                        <li>Expect&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">5.1</a>, <a href="#rfc.xref.header.expect.2">6.5.14</a>, <a href="#rfc.iref.h.12"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3.2</a>, <a href="#rfc.xref.header.expect.4">C</a></li>
     5047                        <li>From&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">5.5</a>, <a href="#rfc.iref.h.13"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3.2</a></li>
     5048                        <li>Location&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">4.3.3</a>, <a href="#rfc.xref.header.location.2">6.4</a>, <a href="#rfc.xref.header.location.3">7</a>, <a href="#rfc.iref.h.14"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3.2</a>, <a href="#rfc.xref.header.location.5">C</a></li>
     5049                        <li>Max-Forwards&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">4.3.7</a>, <a href="#rfc.xref.header.max-forwards.2">4.3.8</a>, <a href="#rfc.xref.header.max-forwards.3">5.1</a>, <a href="#rfc.iref.h.15"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3.2</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>
     5050                        <li>MIME-Version&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">11.3.2</a>, <a href="#rfc.iref.h.20"><b>A.1</b></a></li>
     5051                        <li>Referer&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">5.5</a>, <a href="#rfc.iref.h.16"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3.2</a>, <a href="#rfc.xref.header.referer.3">C</a></li>
     5052                        <li>Retry-After&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">6.6.4</a>, <a href="#rfc.xref.header.retry-after.2">7</a>, <a href="#rfc.iref.h.17"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3.2</a></li>
     5053                        <li>Server&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">7</a>, <a href="#rfc.iref.h.18"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3.2</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>
     5054                        <li>User-Agent&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">3.4.1</a>, <a href="#rfc.xref.header.user-agent.2">5.5</a>, <a href="#rfc.iref.h.19"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3.2</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li>
    50565055                     </ul>
    50575056                  </li>
    … …  
    50635062            </li>
    50645063            <li><a id="rfc.index.L" href="#rfc.index.L"><b>L</b></a><ul>
    5065                   <li>Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">4.3.3</a>, <a href="#rfc.xref.header.location.2">6.4</a>, <a href="#rfc.xref.header.location.3">7</a>, <a href="#rfc.iref.l.1"><b>11.13</b></a>, <a href="#rfc.xref.header.location.4">12.3.2</a>, <a href="#rfc.xref.header.location.5">C</a></li>
     5064                  <li>Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">4.3.3</a>, <a href="#rfc.xref.header.location.2">6.4</a>, <a href="#rfc.xref.header.location.3">7</a>, <a href="#rfc.iref.l.1"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3.2</a>, <a href="#rfc.xref.header.location.5">C</a></li>
    50665065               </ul>
    50675066            </li>
    50685067            <li><a id="rfc.index.M" href="#rfc.index.M"><b>M</b></a><ul>
    5069                   <li>Max-Forwards header field&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">4.3.7</a>, <a href="#rfc.xref.header.max-forwards.2">4.3.8</a>, <a href="#rfc.xref.header.max-forwards.3">5.1</a>, <a href="#rfc.iref.m.9"><b>11.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">12.3.2</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>
     5068                  <li>Max-Forwards header field&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">4.3.7</a>, <a href="#rfc.xref.header.max-forwards.2">4.3.8</a>, <a href="#rfc.xref.header.max-forwards.3">5.1</a>, <a href="#rfc.iref.m.9"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3.2</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>
    50705069                  <li>Methods&nbsp;&nbsp;
    50715070                     <ul>
    5072                         <li>CONNECT&nbsp;&nbsp;<a href="#rfc.xref.CONNECT.1">4.1</a>, <a href="#rfc.iref.m.6"><b>4.3.6</b></a>, <a href="#rfc.xref.CONNECT.2">12.1.3</a>, <a href="#rfc.xref.CONNECT.3">C</a></li>
    5073                         <li>DELETE&nbsp;&nbsp;<a href="#rfc.xref.DELETE.1">4.1</a>, <a href="#rfc.iref.m.5"><b>4.3.5</b></a>, <a href="#rfc.xref.DELETE.2">12.1.3</a></li>
    5074                         <li>GET&nbsp;&nbsp;<a href="#rfc.xref.GET.1">4.1</a>, <a href="#rfc.iref.m.1"><b>4.3.1</b></a>, <a href="#rfc.xref.GET.2">12.1.3</a></li>
    5075                         <li>HEAD&nbsp;&nbsp;<a href="#rfc.xref.HEAD.1">4.1</a>, <a href="#rfc.iref.m.2"><b>4.3.2</b></a>, <a href="#rfc.xref.HEAD.2">12.1.3</a></li>
    5076                         <li>OPTIONS&nbsp;&nbsp;<a href="#rfc.xref.OPTIONS.1">4.1</a>, <a href="#rfc.iref.m.7"><b>4.3.7</b></a>, <a href="#rfc.xref.OPTIONS.2">11.14</a>, <a href="#rfc.xref.OPTIONS.3">12.1.3</a></li>
    5077                         <li>POST&nbsp;&nbsp;<a href="#rfc.xref.POST.1">4.1</a>, <a href="#rfc.iref.m.3"><b>4.3.3</b></a>, <a href="#rfc.xref.POST.2">12.1.3</a>, <a href="#rfc.xref.POST.3">C</a></li>
    5078                         <li>PUT&nbsp;&nbsp;<a href="#rfc.xref.PUT.1">4.1</a>, <a href="#rfc.iref.m.4"><b>4.3.4</b></a>, <a href="#rfc.xref.PUT.2">12.1.3</a>, <a href="#rfc.xref.PUT.3">C</a></li>
    5079                         <li>TRACE&nbsp;&nbsp;<a href="#rfc.xref.TRACE.1">4.1</a>, <a href="#rfc.iref.m.8"><b>4.3.8</b></a>, <a href="#rfc.xref.TRACE.2">11.14</a>, <a href="#rfc.xref.TRACE.3">12.1.3</a>, <a href="#rfc.xref.TRACE.4">13.1</a></li>
     5071                        <li>CONNECT&nbsp;&nbsp;<a href="#rfc.xref.CONNECT.1">4.1</a>, <a href="#rfc.iref.m.6"><b>4.3.6</b></a>, <a href="#rfc.xref.CONNECT.2">11.1.3</a>, <a href="#rfc.xref.CONNECT.3">C</a></li>
     5072                        <li>DELETE&nbsp;&nbsp;<a href="#rfc.xref.DELETE.1">4.1</a>, <a href="#rfc.iref.m.5"><b>4.3.5</b></a>, <a href="#rfc.xref.DELETE.2">11.1.3</a></li>
     5073                        <li>GET&nbsp;&nbsp;<a href="#rfc.xref.GET.1">4.1</a>, <a href="#rfc.iref.m.1"><b>4.3.1</b></a>, <a href="#rfc.xref.GET.2">11.1.3</a></li>
     5074                        <li>HEAD&nbsp;&nbsp;<a href="#rfc.xref.HEAD.1">4.1</a>, <a href="#rfc.iref.m.2"><b>4.3.2</b></a>, <a href="#rfc.xref.HEAD.2">11.1.3</a></li>
     5075                        <li>OPTIONS&nbsp;&nbsp;<a href="#rfc.xref.OPTIONS.1">4.1</a>, <a href="#rfc.iref.m.7"><b>4.3.7</b></a>, <a href="#rfc.xref.OPTIONS.2">10.14</a>, <a href="#rfc.xref.OPTIONS.3">11.1.3</a></li>
     5076                        <li>POST&nbsp;&nbsp;<a href="#rfc.xref.POST.1">4.1</a>, <a href="#rfc.iref.m.3"><b>4.3.3</b></a>, <a href="#rfc.xref.POST.2">11.1.3</a>, <a href="#rfc.xref.POST.3">C</a></li>
     5077                        <li>PUT&nbsp;&nbsp;<a href="#rfc.xref.PUT.1">4.1</a>, <a href="#rfc.iref.m.4"><b>4.3.4</b></a>, <a href="#rfc.xref.PUT.2">11.1.3</a>, <a href="#rfc.xref.PUT.3">C</a></li>
     5078                        <li>TRACE&nbsp;&nbsp;<a href="#rfc.xref.TRACE.1">4.1</a>, <a href="#rfc.iref.m.8"><b>4.3.8</b></a>, <a href="#rfc.xref.TRACE.2">10.14</a>, <a href="#rfc.xref.TRACE.3">11.1.3</a>, <a href="#rfc.xref.TRACE.4">12.1</a></li>
    50805079                     </ul>
    50815080                  </li>
    5082                   <li>MIME-Version header field&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">12.3.2</a>, <a href="#rfc.iref.m.10"><b>A.1</b></a></li>
     5081                  <li>MIME-Version header field&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">11.3.2</a>, <a href="#rfc.iref.m.10"><b>A.1</b></a></li>
    50835082               </ul>
    50845083            </li>
    50855084            <li><a id="rfc.index.O" href="#rfc.index.O"><b>O</b></a><ul>
    5086                   <li>OPTIONS method&nbsp;&nbsp;<a href="#rfc.xref.OPTIONS.1">4.1</a>, <a href="#rfc.iref.o.1"><b>4.3.7</b></a>, <a href="#rfc.xref.OPTIONS.2">11.14</a>, <a href="#rfc.xref.OPTIONS.3">12.1.3</a></li>
     5085                  <li>OPTIONS method&nbsp;&nbsp;<a href="#rfc.xref.OPTIONS.1">4.1</a>, <a href="#rfc.iref.o.1"><b>4.3.7</b></a>, <a href="#rfc.xref.OPTIONS.2">10.14</a>, <a href="#rfc.xref.OPTIONS.3">11.1.3</a></li>
    50875086               </ul>
    50885087            </li>
    50895088            <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul>
    5090                   <li><em>Part1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1</a>, <a href="#rfc.xref.Part1.2">1.1</a>, <a href="#rfc.xref.Part1.3">1.2</a>, <a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.7">3</a>, <a href="#rfc.xref.Part1.8">3.1</a>, <a href="#rfc.xref.Part1.9">4.3.6</a>, <a href="#rfc.xref.Part1.10">4.3.7</a>, <a href="#rfc.xref.Part1.11">4.3.8</a>, <a href="#rfc.xref.Part1.12">4.3.8</a>, <a href="#rfc.xref.Part1.13">5.1</a>, <a href="#rfc.xref.Part1.14">5.5</a>, <a href="#rfc.xref.Part1.15">6.2.1</a>, <a href="#rfc.xref.Part1.16">6.2.2</a>, <a href="#rfc.xref.Part1.17">6.3.4</a>, <a href="#rfc.xref.Part1.18">6.3.6</a>, <a href="#rfc.xref.Part1.19">6.5.15</a>, <a href="#rfc.xref.Part1.20">6.6.6</a>, <a href="#rfc.xref.Part1.21">7</a>, <a href="#rfc.xref.Part1.22">8.4</a>, <a href="#rfc.xref.Part1.23">8.4</a>, <a href="#rfc.xref.Part1.24">8.4</a>, <a href="#rfc.xref.Part1.25">9.1</a>, <a href="#rfc.xref.Part1.26">9.2</a>, <a href="#rfc.xref.Part1.27">11.8</a>, <a href="#rfc.xref.Part1.28">11.11</a>, <a href="#rfc.xref.Part1.29">11.17</a>, <a href="#rfc.xref.Part1.30">11.17</a>, <a href="#rfc.xref.Part1.31">11.18</a>, <a href="#rfc.xref.Part1.32">12.1.2</a>, <a href="#rfc.xref.Part1.33">12.3.1</a>, <a href="#rfc.xref.Part1.34">12.3.1</a>, <a href="#rfc.xref.Part1.35">12.3.1</a>, <a href="#rfc.xref.Part1.36">12.3.1</a>, <a href="#rfc.xref.Part1.37">12.3.1</a>, <a href="#rfc.xref.Part1.38">12.3.1</a>, <a href="#rfc.xref.Part1.39">12.4</a>, <a href="#rfc.xref.Part1.40">12.4.1</a>, <a href="#rfc.xref.Part1.41">12.4.1</a>, <a href="#rfc.xref.Part1.42">12.4.2</a>, <a href="#rfc.xref.Part1.43">12.4.2</a>, <a href="#rfc.xref.Part1.44">12.4.2</a>, <a href="#rfc.xref.Part1.45">14</a>, <a href="#Part1"><b>15.1</b></a>, <a href="#rfc.xref.Part1.46">C</a>, <a href="#rfc.xref.Part1.47">D</a>, <a href="#rfc.xref.Part1.48">D</a>, <a href="#rfc.xref.Part1.49">D</a>, <a href="#rfc.xref.Part1.50">D</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.54">D</a>, <a href="#rfc.xref.Part1.55">D</a>, <a href="#rfc.xref.Part1.56">D</a>, <a href="#rfc.xref.Part1.57">D</a><ul>
     5089                  <li><em>Part1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1</a>, <a href="#rfc.xref.Part1.2">1.1</a>, <a href="#rfc.xref.Part1.3">1.2</a>, <a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.7">3</a>, <a href="#rfc.xref.Part1.8">3.1</a>, <a href="#rfc.xref.Part1.9">4.3.6</a>, <a href="#rfc.xref.Part1.10">4.3.7</a>, <a href="#rfc.xref.Part1.11">4.3.8</a>, <a href="#rfc.xref.Part1.12">4.3.8</a>, <a href="#rfc.xref.Part1.13">5.1</a>, <a href="#rfc.xref.Part1.14">5.5</a>, <a href="#rfc.xref.Part1.15">6.2.1</a>, <a href="#rfc.xref.Part1.16">6.2.2</a>, <a href="#rfc.xref.Part1.17">6.3.4</a>, <a href="#rfc.xref.Part1.18">6.3.6</a>, <a href="#rfc.xref.Part1.19">6.5.15</a>, <a href="#rfc.xref.Part1.20">6.6.6</a>, <a href="#rfc.xref.Part1.21">7</a>, <a href="#rfc.xref.Part1.22">8.4</a>, <a href="#rfc.xref.Part1.23">8.4</a>, <a href="#rfc.xref.Part1.24">8.4</a>, <a href="#rfc.xref.Part1.25">9.1</a>, <a href="#rfc.xref.Part1.26">9.2</a>, <a href="#rfc.xref.Part1.27">10.8</a>, <a href="#rfc.xref.Part1.28">10.11</a>, <a href="#rfc.xref.Part1.29">10.17</a>, <a href="#rfc.xref.Part1.30">10.17</a>, <a href="#rfc.xref.Part1.31">10.18</a>, <a href="#rfc.xref.Part1.32">11.1.2</a>, <a href="#rfc.xref.Part1.33">11.3.1</a>, <a href="#rfc.xref.Part1.34">11.3.1</a>, <a href="#rfc.xref.Part1.35">11.3.1</a>, <a href="#rfc.xref.Part1.36">11.3.1</a>, <a href="#rfc.xref.Part1.37">11.3.1</a>, <a href="#rfc.xref.Part1.38">11.3.1</a>, <a href="#rfc.xref.Part1.39">11.4</a>, <a href="#rfc.xref.Part1.40">11.4.1</a>, <a href="#rfc.xref.Part1.41">11.4.1</a>, <a href="#rfc.xref.Part1.42">11.4.2</a>, <a href="#rfc.xref.Part1.43">11.4.2</a>, <a href="#rfc.xref.Part1.44">11.4.2</a>, <a href="#rfc.xref.Part1.45">13</a>, <a href="#Part1"><b>14.1</b></a>, <a href="#rfc.xref.Part1.46">C</a>, <a href="#rfc.xref.Part1.47">D</a>, <a href="#rfc.xref.Part1.48">D</a>, <a href="#rfc.xref.Part1.49">D</a>, <a href="#rfc.xref.Part1.50">D</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.54">D</a>, <a href="#rfc.xref.Part1.55">D</a>, <a href="#rfc.xref.Part1.56">D</a>, <a href="#rfc.xref.Part1.57">D</a><ul>
    50915090                        <li><em>Section 1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.3">1.2</a></li>
    50925091                        <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.17">6.3.4</a></li>
    … …  
    50945093                        <li><em>Section 2.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.20">6.6.6</a></li>
    50955094                        <li><em>Section 2.7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.54">D</a>, <a href="#rfc.xref.Part1.56">D</a>, <a href="#rfc.xref.Part1.57">D</a></li>
    5096                         <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.29">11.17</a>, <a href="#rfc.xref.Part1.31">11.18</a>, <a href="#rfc.xref.Part1.33">12.3.1</a>, <a href="#rfc.xref.Part1.36">12.3.1</a></li>
     5095                        <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.29">10.17</a>, <a href="#rfc.xref.Part1.31">10.18</a>, <a href="#rfc.xref.Part1.33">11.3.1</a>, <a href="#rfc.xref.Part1.36">11.3.1</a></li>
    50975096                        <li><em>Section 3.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.48">D</a>, <a href="#rfc.xref.Part1.49">D</a>, <a href="#rfc.xref.Part1.50">D</a></li>
    5098                         <li><em>Section 3.2.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.35">12.3.1</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.55">D</a></li>
    5099                         <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.7">3</a>, <a href="#rfc.xref.Part1.18">6.3.6</a>, <a href="#rfc.xref.Part1.26">9.2</a>, <a href="#rfc.xref.Part1.32">12.1.2</a></li>
     5097                        <li><em>Section 3.2.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.35">11.3.1</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.55">D</a></li>
     5098                        <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.7">3</a>, <a href="#rfc.xref.Part1.18">6.3.6</a>, <a href="#rfc.xref.Part1.26">9.2</a>, <a href="#rfc.xref.Part1.32">11.1.2</a></li>
    51005099                        <li><em>Section 3.3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.25">9.1</a></li>
    5101                         <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.40">12.4.1</a></li>
    5102                         <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.38">12.3.1</a></li>
    5103                         <li><em>Section 4.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.22">8.4</a>, <a href="#rfc.xref.Part1.42">12.4.2</a></li>
    5104                         <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.39">12.4</a>, <a href="#rfc.xref.Part1.41">12.4.1</a></li>
    5105                         <li><em>Section 4.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.23">8.4</a>, <a href="#rfc.xref.Part1.43">12.4.2</a></li>
    5106                         <li><em>Section 4.2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.24">8.4</a>, <a href="#rfc.xref.Part1.44">12.4.2</a></li>
     5100                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.40">11.4.1</a></li>
     5101                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.38">11.3.1</a></li>
     5102                        <li><em>Section 4.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.22">8.4</a>, <a href="#rfc.xref.Part1.42">11.4.2</a></li>
     5103                        <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.39">11.4</a>, <a href="#rfc.xref.Part1.41">11.4.1</a></li>
     5104                        <li><em>Section 4.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.23">8.4</a>, <a href="#rfc.xref.Part1.43">11.4.2</a></li>
     5105                        <li><em>Section 4.2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.24">8.4</a>, <a href="#rfc.xref.Part1.44">11.4.2</a></li>
    51075106                        <li><em>Section 4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.14">5.5</a></li>
    51085107                        <li><em>Section 5.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.9">4.3.6</a>, <a href="#rfc.xref.Part1.10">4.3.7</a></li>
    51095108                        <li><em>Section 5.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.13">5.1</a></li>
    5110                         <li><em>Section 5.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.8">3.1</a>, <a href="#rfc.xref.Part1.21">7</a>, <a href="#rfc.xref.Part1.27">11.8</a></li>
    5111                         <li><em>Section 5.7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.11">4.3.8</a>, <a href="#rfc.xref.Part1.30">11.17</a>, <a href="#rfc.xref.Part1.46">C</a></li>
    5112                         <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.37">12.3.1</a></li>
    5113                         <li><em>Section 6.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.15">6.2.1</a>, <a href="#rfc.xref.Part1.28">11.11</a></li>
     5109                        <li><em>Section 5.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.8">3.1</a>, <a href="#rfc.xref.Part1.21">7</a>, <a href="#rfc.xref.Part1.27">10.8</a></li>
     5110                        <li><em>Section 5.7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.11">4.3.8</a>, <a href="#rfc.xref.Part1.30">10.17</a>, <a href="#rfc.xref.Part1.46">C</a></li>
     5111                        <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.37">11.3.1</a></li>
     5112                        <li><em>Section 6.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.15">6.2.1</a>, <a href="#rfc.xref.Part1.28">10.11</a></li>
    51145113                        <li><em>Section 6.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.16">6.2.2</a>, <a href="#rfc.xref.Part1.19">6.5.15</a></li>
    51155114                        <li><em>Section 7.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.12">4.3.8</a></li>
    5116                         <li><em>Section 9</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.45">14</a></li>
    5117                         <li><em>Appendix B</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.34">12.3.1</a></li>
     5115                        <li><em>Section 9</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.45">13</a></li>
     5116                        <li><em>Appendix B</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.34">11.3.1</a></li>
    51185117                     </ul>
    51195118                  </li>
    5120                   <li><em>Part4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">3.2</a>, <a href="#rfc.xref.Part4.2">3.2</a>, <a href="#rfc.xref.Part4.3">4.3.1</a>, <a href="#rfc.xref.Part4.4">5.2</a>, <a href="#rfc.xref.Part4.5">5.2</a>, <a href="#rfc.xref.Part4.6">5.2</a>, <a href="#rfc.xref.Part4.7">5.2</a>, <a href="#rfc.xref.Part4.8">5.2</a>, <a href="#rfc.xref.Part4.9">6.1</a>, <a href="#rfc.xref.Part4.10">6.1</a>, <a href="#rfc.xref.Part4.11">6.1</a>, <a href="#rfc.xref.Part4.12">6.3.2</a>, <a href="#rfc.xref.Part4.13">6.4</a>, <a href="#rfc.xref.Part4.14">7</a>, <a href="#Part4"><b>15.1</b></a>, <a href="#rfc.xref.Part4.15">F.2</a><ul>
     5119                  <li><em>Part4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">3.2</a>, <a href="#rfc.xref.Part4.2">3.2</a>, <a href="#rfc.xref.Part4.3">4.3.1</a>, <a href="#rfc.xref.Part4.4">5.2</a>, <a href="#rfc.xref.Part4.5">5.2</a>, <a href="#rfc.xref.Part4.6">5.2</a>, <a href="#rfc.xref.Part4.7">5.2</a>, <a href="#rfc.xref.Part4.8">5.2</a>, <a href="#rfc.xref.Part4.9">6.1</a>, <a href="#rfc.xref.Part4.10">6.1</a>, <a href="#rfc.xref.Part4.11">6.1</a>, <a href="#rfc.xref.Part4.12">6.3.2</a>, <a href="#rfc.xref.Part4.13">6.4</a>, <a href="#rfc.xref.Part4.14">7</a>, <a href="#Part4"><b>14.1</b></a>, <a href="#rfc.xref.Part4.15">F.2</a><ul>
    51215120                        <li><em>Section 2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.2">3.2</a></li>
    51225121                        <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">3.2</a>, <a href="#rfc.xref.Part4.12">6.3.2</a>, <a href="#rfc.xref.Part4.14">7</a></li>
    … …  
    51305129                     </ul>
    51315130                  </li>
    5132                   <li><em>Part5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.1">4.3.1</a>, <a href="#rfc.xref.Part5.2">4.3.1</a>, <a href="#rfc.xref.Part5.3">4.3.4</a>, <a href="#rfc.xref.Part5.4">5.1</a>, <a href="#rfc.xref.Part5.5">5.2</a>, <a href="#rfc.xref.Part5.6">6.1</a>, <a href="#rfc.xref.Part5.7">6.1</a>, <a href="#rfc.xref.Part5.8">6.1</a>, <a href="#rfc.xref.Part5.9">7</a>, <a href="#rfc.xref.Part5.10">9.1</a>, <a href="#Part5"><b>15.1</b></a><ul>
     5131                  <li><em>Part5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.1">4.3.1</a>, <a href="#rfc.xref.Part5.2">4.3.1</a>, <a href="#rfc.xref.Part5.3">4.3.4</a>, <a href="#rfc.xref.Part5.4">5.1</a>, <a href="#rfc.xref.Part5.5">5.2</a>, <a href="#rfc.xref.Part5.6">6.1</a>, <a href="#rfc.xref.Part5.7">6.1</a>, <a href="#rfc.xref.Part5.8">6.1</a>, <a href="#rfc.xref.Part5.9">7</a>, <a href="#rfc.xref.Part5.10">9.1</a>, <a href="#Part5"><b>14.1</b></a><ul>
    51335132                        <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.6">6.1</a></li>
    51345133                        <li><em>Section 3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.7">6.1</a></li>
    … …  
    51405139                     </ul>
    51415140                  </li>
    5142                   <li><em>Part6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">3.2</a>, <a href="#rfc.xref.Part6.2">4.2.3</a>, <a href="#rfc.xref.Part6.3">4.3.1</a>, <a href="#rfc.xref.Part6.4">4.3.2</a>, <a href="#rfc.xref.Part6.5">4.3.3</a>, <a href="#rfc.xref.Part6.6">4.3.4</a>, <a href="#rfc.xref.Part6.7">4.3.5</a>, <a href="#rfc.xref.Part6.8">6.3.1</a>, <a href="#rfc.xref.Part6.9">6.3.4</a>, <a href="#rfc.xref.Part6.10">6.3.4</a>, <a href="#rfc.xref.Part6.11">6.3.4</a>, <a href="#rfc.xref.Part6.12">6.4.1</a>, <a href="#rfc.xref.Part6.13">6.4.2</a>, <a href="#rfc.xref.Part6.14">6.5.9</a>, <a href="#rfc.xref.Part6.15">7</a>, <a href="#rfc.xref.Part6.16">7</a>, <a href="#rfc.xref.Part6.17">10.1</a>, <a href="#rfc.xref.Part6.18">12.2.2</a>, <a href="#rfc.xref.Part6.19">12.3.1</a>, <a href="#Part6"><b>15.1</b></a><ul>
    5143                         <li><em>Section 4.1.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.5">4.3.3</a></li>
    5144                         <li><em>Section 4.1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.8">6.3.1</a>, <a href="#rfc.xref.Part6.11">6.3.4</a>, <a href="#rfc.xref.Part6.12">6.4.1</a>, <a href="#rfc.xref.Part6.13">6.4.2</a>, <a href="#rfc.xref.Part6.14">6.5.9</a></li>
    5145                         <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.4">4.3.2</a></li>
    5146                         <li><em>Section 6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.6">4.3.4</a>, <a href="#rfc.xref.Part6.7">4.3.5</a></li>
    5147                         <li><em>Section 7.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.15">7</a></li>
    5148                         <li><em>Section 7.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.9">6.3.4</a></li>
     5141                  <li><em>Part6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">3.2</a>, <a href="#rfc.xref.Part6.2">3.4.1</a>, <a href="#rfc.xref.Part6.3">4.2.3</a>, <a href="#rfc.xref.Part6.4">4.3.1</a>, <a href="#rfc.xref.Part6.5">4.3.2</a>, <a href="#rfc.xref.Part6.6">4.3.3</a>, <a href="#rfc.xref.Part6.7">4.3.4</a>, <a href="#rfc.xref.Part6.8">4.3.5</a>, <a href="#rfc.xref.Part6.9">6.3.1</a>, <a href="#rfc.xref.Part6.10">6.3.4</a>, <a href="#rfc.xref.Part6.11">6.3.4</a>, <a href="#rfc.xref.Part6.12">6.3.4</a>, <a href="#rfc.xref.Part6.13">6.4.1</a>, <a href="#rfc.xref.Part6.14">6.4.2</a>, <a href="#rfc.xref.Part6.15">6.5.9</a>, <a href="#rfc.xref.Part6.16">7</a>, <a href="#rfc.xref.Part6.17">7</a>, <a href="#rfc.xref.Part6.18">11.2.2</a>, <a href="#rfc.xref.Part6.19">11.3.1</a>, <a href="#Part6"><b>14.1</b></a><ul>
     5142                        <li><em>Section 4.1.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.6">4.3.3</a></li>
     5143                        <li><em>Section 4.1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.9">6.3.1</a>, <a href="#rfc.xref.Part6.12">6.3.4</a>, <a href="#rfc.xref.Part6.13">6.4.1</a>, <a href="#rfc.xref.Part6.14">6.4.2</a>, <a href="#rfc.xref.Part6.15">6.5.9</a></li>
     5144                        <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.5">4.3.2</a></li>
     5145                        <li><em>Section 6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.7">4.3.4</a>, <a href="#rfc.xref.Part6.8">4.3.5</a></li>
     5146                        <li><em>Section 7.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.16">7</a></li>
     5147                        <li><em>Section 7.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.10">6.3.4</a></li>
    51495148                        <li><em>Section 7.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">3.2</a></li>
    5150                         <li><em>Section 7.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.16">7</a>, <a href="#rfc.xref.Part6.17">10.1</a></li>
    5151                         <li><em>Section 7.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.10">6.3.4</a></li>
     5149                        <li><em>Section 7.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.2">3.4.1</a>, <a href="#rfc.xref.Part6.17">7</a></li>
     5150                        <li><em>Section 7.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.11">6.3.4</a></li>
    51525151                     </ul>
    51535152                  </li>
    5154                   <li><em>Part7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.1">5.4</a>, <a href="#rfc.xref.Part7.2">5.4</a>, <a href="#rfc.xref.Part7.3">6.1</a>, <a href="#rfc.xref.Part7.4">6.1</a>, <a href="#rfc.xref.Part7.5">6.1</a>, <a href="#rfc.xref.Part7.6">7</a>, <a href="#rfc.xref.Part7.7">7</a>, <a href="#Part7"><b>15.1</b></a><ul>
     5153                  <li><em>Part7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.1">5.4</a>, <a href="#rfc.xref.Part7.2">5.4</a>, <a href="#rfc.xref.Part7.3">6.1</a>, <a href="#rfc.xref.Part7.4">6.1</a>, <a href="#rfc.xref.Part7.5">6.1</a>, <a href="#rfc.xref.Part7.6">7</a>, <a href="#rfc.xref.Part7.7">7</a>, <a href="#Part7"><b>14.1</b></a><ul>
    51555154                        <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.3">6.1</a></li>
    51565155                        <li><em>Section 3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.4">6.1</a></li>
    … …  
    51635162                  </li>
    51645163                  <li>payload&nbsp;&nbsp;<a href="#rfc.iref.p.3">9</a></li>
    5165                   <li>POST method&nbsp;&nbsp;<a href="#rfc.xref.POST.1">4.1</a>, <a href="#rfc.iref.p.1"><b>4.3.3</b></a>, <a href="#rfc.xref.POST.2">12.1.3</a>, <a href="#rfc.xref.POST.3">C</a></li>
    5166                   <li>PUT method&nbsp;&nbsp;<a href="#rfc.xref.PUT.1">4.1</a>, <a href="#rfc.iref.p.2"><b>4.3.4</b></a>, <a href="#rfc.xref.PUT.2">12.1.3</a>, <a href="#rfc.xref.PUT.3">C</a></li>
     5164                  <li>POST method&nbsp;&nbsp;<a href="#rfc.xref.POST.1">4.1</a>, <a href="#rfc.iref.p.1"><b>4.3.3</b></a>, <a href="#rfc.xref.POST.2">11.1.3</a>, <a href="#rfc.xref.POST.3">C</a></li>
     5165                  <li>PUT method&nbsp;&nbsp;<a href="#rfc.xref.PUT.1">4.1</a>, <a href="#rfc.iref.p.2"><b>4.3.4</b></a>, <a href="#rfc.xref.PUT.2">11.1.3</a>, <a href="#rfc.xref.PUT.3">C</a></li>
    51675166               </ul>
    51685167            </li>
    51695168            <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul>
    5170                   <li>Referer header field&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">5.5</a>, <a href="#rfc.iref.r.2"><b>11.15</b></a>, <a href="#rfc.xref.header.referer.2">12.3.2</a>, <a href="#rfc.xref.header.referer.3">C</a></li>
     5169                  <li>Referer header field&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">5.5</a>, <a href="#rfc.iref.r.2"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3.2</a>, <a href="#rfc.xref.header.referer.3">C</a></li>
    51715170                  <li>representation&nbsp;&nbsp;<a href="#rfc.iref.r.1">3</a></li>
    5172                   <li><em>REST</em>&nbsp;&nbsp;<a href="#rfc.xref.REST.1">4.1</a>, <a href="#REST"><b>15.2</b></a></li>
    5173                   <li>Retry-After header field&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">6.6.4</a>, <a href="#rfc.xref.header.retry-after.2">7</a>, <a href="#rfc.iref.r.3"><b>11.16</b></a>, <a href="#rfc.xref.header.retry-after.3">12.3.2</a></li>
    5174                   <li><em>RFC1123</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1123.1">8.1</a>, <a href="#rfc.xref.RFC1123.2">8.1</a>, <a href="#RFC1123"><b>15.2</b></a><ul>
     5171                  <li><em>REST</em>&nbsp;&nbsp;<a href="#rfc.xref.REST.1">4.1</a>, <a href="#REST"><b>14.2</b></a></li>
     5172                  <li>Retry-After header field&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">6.6.4</a>, <a href="#rfc.xref.header.retry-after.2">7</a>, <a href="#rfc.iref.r.3"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3.2</a></li>
     5173                  <li><em>RFC1123</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1123.1">8.1</a>, <a href="#rfc.xref.RFC1123.2">8.1</a>, <a href="#RFC1123"><b>14.2</b></a><ul>
    51755174                        <li><em>Section 5.2.14</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1123.2">8.1</a></li>
    51765175                     </ul>
    51775176                  </li>
    5178                   <li><em>RFC1945</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1945.1">6.4</a>, <a href="#RFC1945"><b>15.2</b></a>, <a href="#rfc.xref.RFC1945.2">B</a><ul>
     5177                  <li><em>RFC1945</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1945.1">6.4</a>, <a href="#RFC1945"><b>14.2</b></a>, <a href="#rfc.xref.RFC1945.2">B</a><ul>
    51795178                        <li><em>Section 9.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1945.1">6.4</a></li>
    51805179                     </ul>
    51815180                  </li>
    5182                   <li><em>RFC1950</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1950.1">12.4.2</a>, <a href="#RFC1950"><b>15.1</b></a></li>
    5183                   <li><em>RFC1951</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1951.1">12.4.2</a>, <a href="#RFC1951"><b>15.1</b></a></li>
    5184                   <li><em>RFC1952</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1952.1">12.4.2</a>, <a href="#RFC1952"><b>15.1</b></a></li>
    5185                   <li><em>RFC2045</em>&nbsp;&nbsp;<a href="#RFC2045"><b>15.1</b></a>, <a href="#rfc.xref.RFC2045.1">A</a>, <a href="#rfc.xref.RFC2045.2">A.1</a></li>
    5186                   <li><em>RFC2046</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.1">3.3</a>, <a href="#rfc.xref.RFC2046.2">8.5</a>, <a href="#rfc.xref.RFC2046.3">8.5.2</a>, <a href="#RFC2046"><b>15.1</b></a>, <a href="#rfc.xref.RFC2046.4">A.2</a><ul>
     5181                  <li><em>RFC1950</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1950.1">11.4.2</a>, <a href="#RFC1950"><b>14.1</b></a></li>
     5182                  <li><em>RFC1951</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1951.1">11.4.2</a>, <a href="#RFC1951"><b>14.1</b></a></li>
     5183                  <li><em>RFC1952</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1952.1">11.4.2</a>, <a href="#RFC1952"><b>14.1</b></a></li>
     5184                  <li><em>RFC2045</em>&nbsp;&nbsp;<a href="#RFC2045"><b>14.1</b></a>, <a href="#rfc.xref.RFC2045.1">A</a>, <a href="#rfc.xref.RFC2045.2">A.1</a></li>
     5185                  <li><em>RFC2046</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.1">3.3</a>, <a href="#rfc.xref.RFC2046.2">8.5</a>, <a href="#rfc.xref.RFC2046.3">8.5.2</a>, <a href="#RFC2046"><b>14.1</b></a>, <a href="#rfc.xref.RFC2046.4">A.2</a><ul>
    51875186                        <li><em>Section 4.5.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.1">3.3</a></li>
    51885187                        <li><em>Section 5.1.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.3">8.5.2</a></li>
    51895188                     </ul>
    51905189                  </li>
    5191                   <li><em>RFC2049</em>&nbsp;&nbsp;<a href="#RFC2049"><b>15.2</b></a>, <a href="#rfc.xref.RFC2049.1">A.2</a><ul>
     5190                  <li><em>RFC2049</em>&nbsp;&nbsp;<a href="#RFC2049"><b>14.2</b></a>, <a href="#rfc.xref.RFC2049.1">A.2</a><ul>
    51925191                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2049.1">A.2</a></li>
    51935192                     </ul>
    51945193                  </li>
    5195                   <li><em>RFC2068</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2068.1">6.4</a>, <a href="#rfc.xref.RFC2068.2">6.4</a>, <a href="#RFC2068"><b>15.2</b></a>, <a href="#rfc.xref.RFC2068.3">B</a><ul>
     5194                  <li><em>RFC2068</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2068.1">6.4</a>, <a href="#rfc.xref.RFC2068.2">6.4</a>, <a href="#RFC2068"><b>14.2</b></a>, <a href="#rfc.xref.RFC2068.3">B</a><ul>
    51965195                        <li><em>Section 10.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2068.2">6.4</a></li>
    51975196                        <li><em>Section 10.3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2068.1">6.4</a></li>
    51985197                     </ul>
    51995198                  </li>
    5200                   <li><em>RFC2076</em>&nbsp;&nbsp;<a href="#RFC2076"><b>15.2</b></a>, <a href="#rfc.xref.RFC2076.1">B</a></li>
    5201                   <li><em>RFC2119</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2119.1">1.1</a>, <a href="#RFC2119"><b>15.1</b></a></li>
    5202                   <li><em>RFC2277</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2277.1">8.3</a>, <a href="#RFC2277"><b>15.2</b></a></li>
    5203                   <li><em>RFC2295</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2295.1">10</a>, <a href="#RFC2295"><b>15.2</b></a></li>
    5204                   <li><em>RFC2388</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2388.1">8.5.2</a>, <a href="#RFC2388"><b>15.2</b></a></li>
    5205                   <li><em>RFC2557</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2557.1">11.8</a>, <a href="#RFC2557"><b>15.2</b></a>, <a href="#rfc.xref.RFC2557.2">A.6</a><ul>
    5206                         <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2557.1">11.8</a></li>
     5199                  <li><em>RFC2076</em>&nbsp;&nbsp;<a href="#RFC2076"><b>14.2</b></a>, <a href="#rfc.xref.RFC2076.1">B</a></li>
     5200                  <li><em>RFC2119</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2119.1">1.1</a>, <a href="#RFC2119"><b>14.1</b></a></li>
     5201                  <li><em>RFC2277</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2277.1">8.3</a>, <a href="#RFC2277"><b>14.2</b></a></li>
     5202                  <li><em>RFC2295</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2295.1">3.4</a>, <a href="#RFC2295"><b>14.2</b></a></li>
     5203                  <li><em>RFC2388</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2388.1">8.5.2</a>, <a href="#RFC2388"><b>14.2</b></a></li>
     5204                  <li><em>RFC2557</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2557.1">10.8</a>, <a href="#RFC2557"><b>14.2</b></a>, <a href="#rfc.xref.RFC2557.2">A.6</a><ul>
     5205                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2557.1">10.8</a></li>
    52075206                     </ul>
    52085207                  </li>
    5209                   <li><em>RFC2616</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.1">6.4</a>, <a href="#rfc.xref.RFC2616.2">11.4</a>, <a href="#RFC2616"><b>15.2</b></a>, <a href="#rfc.xref.RFC2616.3">F.1</a><ul>
     5208                  <li><em>RFC2616</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.1">6.4</a>, <a href="#rfc.xref.RFC2616.2">10.4</a>, <a href="#RFC2616"><b>14.2</b></a>, <a href="#rfc.xref.RFC2616.3">F.1</a><ul>
    52105209                        <li><em>Section 10.3.8</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.1">6.4</a></li>
    5211                         <li><em>Section 14.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.2">11.4</a></li>
     5210                        <li><em>Section 14.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.2">10.4</a></li>
    52125211                     </ul>
    52135212                  </li>
    5214                   <li><em>RFC2817</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2817.1">12.2</a>, <a href="#RFC2817"><b>15.2</b></a>, <a href="#rfc.xref.RFC2817.2">C</a>, <a href="#rfc.xref.RFC2817.3">C</a>, <a href="#rfc.xref.RFC2817.4">C</a><ul>
    5215                         <li><em>Section 7.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2817.1">12.2</a>, <a href="#rfc.xref.RFC2817.3">C</a></li>
     5213                  <li><em>RFC2817</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2817.1">11.2</a>, <a href="#RFC2817"><b>14.2</b></a>, <a href="#rfc.xref.RFC2817.2">C</a>, <a href="#rfc.xref.RFC2817.3">C</a>, <a href="#rfc.xref.RFC2817.4">C</a><ul>
     5214                        <li><em>Section 7.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2817.1">11.2</a>, <a href="#rfc.xref.RFC2817.3">C</a></li>
    52165215                     </ul>
    52175216                  </li>
    5218                   <li><em>RFC3629</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3629.1">8.3</a>, <a href="#RFC3629"><b>15.2</b></a></li>
    5219                   <li><em>RFC3864</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.1">12.3</a>, <a href="#rfc.xref.RFC3864.2">12.3.1</a>, <a href="#RFC3864"><b>15.2</b></a><ul>
    5220                         <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.2">12.3.1</a></li>
     5217                  <li><em>RFC3629</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3629.1">8.3</a>, <a href="#RFC3629"><b>14.2</b></a></li>
     5218                  <li><em>RFC3864</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.1">11.3</a>, <a href="#rfc.xref.RFC3864.2">11.3.1</a>, <a href="#RFC3864"><b>14.2</b></a><ul>
     5219                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.2">11.3.1</a></li>
    52215220                     </ul>
    52225221                  </li>
    5223                   <li><em>RFC3986</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">11.13</a>, <a href="#rfc.xref.RFC3986.2">11.13</a>, <a href="#RFC3986"><b>15.1</b></a><ul>
    5224                         <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">11.13</a></li>
    5225                         <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.2">11.13</a></li>
     5222                  <li><em>RFC3986</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">10.13</a>, <a href="#rfc.xref.RFC3986.2">10.13</a>, <a href="#RFC3986"><b>14.1</b></a><ul>
     5223                        <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">10.13</a></li>
     5224                        <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.2">10.13</a></li>
    52265225                     </ul>
    52275226                  </li>
    5228                   <li><em>RFC4288</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4288.1">8.5</a>, <a href="#RFC4288"><b>15.2</b></a></li>
    5229                   <li><em>RFC4647</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.1">11.4</a>, <a href="#rfc.xref.RFC4647.2">11.4</a>, <a href="#rfc.xref.RFC4647.3">11.4</a>, <a href="#rfc.xref.RFC4647.4">11.4</a>, <a href="#RFC4647"><b>15.1</b></a><ul>
    5230                         <li><em>Section 2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.1">11.4</a></li>
    5231                         <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.2">11.4</a></li>
    5232                         <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.3">11.4</a></li>
    5233                         <li><em>Section 3.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.4">11.4</a></li>
     5227                  <li><em>RFC4288</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4288.1">8.5</a>, <a href="#RFC4288"><b>14.2</b></a></li>
     5228                  <li><em>RFC4647</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.1">10.4</a>, <a href="#rfc.xref.RFC4647.2">10.4</a>, <a href="#rfc.xref.RFC4647.3">10.4</a>, <a href="#rfc.xref.RFC4647.4">10.4</a>, <a href="#RFC4647"><b>14.1</b></a><ul>
     5229                        <li><em>Section 2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.1">10.4</a></li>
     5230                        <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.2">10.4</a></li>
     5231                        <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.3">10.4</a></li>
     5232                        <li><em>Section 3.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.4">10.4</a></li>
    52345233                     </ul>
    52355234                  </li>
    5236                   <li><em>RFC5226</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">12.1.1</a>, <a href="#rfc.xref.RFC5226.2">12.2.1</a>, <a href="#rfc.xref.RFC5226.3">12.4.1</a>, <a href="#RFC5226"><b>15.2</b></a><ul>
    5237                         <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">12.1.1</a>, <a href="#rfc.xref.RFC5226.2">12.2.1</a>, <a href="#rfc.xref.RFC5226.3">12.4.1</a></li>
     5235                  <li><em>RFC5226</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">11.1.1</a>, <a href="#rfc.xref.RFC5226.2">11.2.1</a>, <a href="#rfc.xref.RFC5226.3">11.4.1</a>, <a href="#RFC5226"><b>14.2</b></a><ul>
     5236                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">11.1.1</a>, <a href="#rfc.xref.RFC5226.2">11.2.1</a>, <a href="#rfc.xref.RFC5226.3">11.4.1</a></li>
    52385237                     </ul>
    52395238                  </li>
    5240                   <li><em>RFC5234</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.1">1.2</a>, <a href="#rfc.xref.RFC5234.2">12.3.1</a>, <a href="#RFC5234"><b>15.1</b></a>, <a href="#rfc.xref.RFC5234.3">D</a><ul>
     5239                  <li><em>RFC5234</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.1">1.2</a>, <a href="#rfc.xref.RFC5234.2">11.3.1</a>, <a href="#RFC5234"><b>14.1</b></a>, <a href="#rfc.xref.RFC5234.3">D</a><ul>
    52415240                        <li><em>Appendix B.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.3">D</a></li>
    52425241                     </ul>
    52435242                  </li>
    5244                   <li><em>RFC5322</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.1">8.1</a>, <a href="#rfc.xref.RFC5322.2">11.10</a>, <a href="#rfc.xref.RFC5322.3">11.12</a>, <a href="#rfc.xref.RFC5322.4">11.12</a>, <a href="#RFC5322"><b>15.2</b></a>, <a href="#rfc.xref.RFC5322.5">A</a><ul>
     5243                  <li><em>RFC5322</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.1">8.1</a>, <a href="#rfc.xref.RFC5322.2">10.10</a>, <a href="#rfc.xref.RFC5322.3">10.12</a>, <a href="#rfc.xref.RFC5322.4">10.12</a>, <a href="#RFC5322"><b>14.2</b></a>, <a href="#rfc.xref.RFC5322.5">A</a><ul>
    52455244                        <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.1">8.1</a></li>
    5246                         <li><em>Section 3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.3">11.12</a>, <a href="#rfc.xref.RFC5322.4">11.12</a></li>
    5247                         <li><em>Section 3.6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.2">11.10</a></li>
     5245                        <li><em>Section 3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.3">10.12</a>, <a href="#rfc.xref.RFC5322.4">10.12</a></li>
     5246                        <li><em>Section 3.6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.2">10.10</a></li>
    52485247                     </ul>
    52495248                  </li>
    5250                   <li><em>RFC5646</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5646.1">8.6</a>, <a href="#rfc.xref.RFC5646.2">8.6</a>, <a href="#rfc.xref.RFC5646.3">8.6</a>, <a href="#RFC5646"><b>15.1</b></a><ul>
     5249                  <li><em>RFC5646</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5646.1">8.6</a>, <a href="#rfc.xref.RFC5646.2">8.6</a>, <a href="#rfc.xref.RFC5646.3">8.6</a>, <a href="#RFC5646"><b>14.1</b></a><ul>
    52515250                        <li><em>Section 2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5646.2">8.6</a></li>
    52525251                     </ul>
    52535252                  </li>
    5254                   <li><em>RFC5789</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5789.1">4.3.4</a>, <a href="#RFC5789"><b>15.2</b></a></li>
    5255                   <li><em>RFC5987</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5987.1">12.3.1</a>, <a href="#RFC5987"><b>15.2</b></a></li>
    5256                   <li><em>RFC6151</em>&nbsp;&nbsp;<a href="#RFC6151"><b>15.2</b></a>, <a href="#rfc.xref.RFC6151.1">C</a></li>
    5257                   <li><em>RFC6266</em>&nbsp;&nbsp;<a href="#RFC6266"><b>15.2</b></a>, <a href="#rfc.xref.RFC6266.1">B</a>, <a href="#rfc.xref.RFC6266.2">C</a></li>
     5253                  <li><em>RFC5789</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5789.1">4.3.4</a>, <a href="#RFC5789"><b>14.2</b></a></li>
     5254                  <li><em>RFC5987</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5987.1">11.3.1</a>, <a href="#RFC5987"><b>14.2</b></a></li>
     5255                  <li><em>RFC6151</em>&nbsp;&nbsp;<a href="#RFC6151"><b>14.2</b></a>, <a href="#rfc.xref.RFC6151.1">C</a></li>
     5256                  <li><em>RFC6266</em>&nbsp;&nbsp;<a href="#RFC6266"><b>14.2</b></a>, <a href="#rfc.xref.RFC6266.1">B</a>, <a href="#rfc.xref.RFC6266.2">C</a></li>
    52585257               </ul>
    52595258            </li>
    … …  
    52615260                  <li>safe&nbsp;&nbsp;<a href="#rfc.iref.s.2"><b>4.2.1</b></a></li>
    52625261                  <li>selected representation&nbsp;&nbsp;<a href="#rfc.iref.s.1"><b>3.2</b></a></li>
    5263                   <li>Server header field&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">7</a>, <a href="#rfc.iref.s.44"><b>11.17</b></a>, <a href="#rfc.xref.header.server.2">12.3.2</a>, <a href="#rfc.xref.header.server.3">13.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>
     5262                  <li>Server header field&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">7</a>, <a href="#rfc.iref.s.44"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3.2</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>
    52645263                  <li>Status Codes&nbsp;&nbsp;
    52655264                     <ul>
    5266                         <li>100 Continue&nbsp;&nbsp;<a href="#rfc.xref.status.100.1">6.1</a>, <a href="#rfc.iref.s.4"><b>6.2.1</b></a>, <a href="#rfc.xref.status.100.2">12.2.3</a></li>
    5267                         <li>101 Switching Protocols&nbsp;&nbsp;<a href="#rfc.xref.status.101.1">6.1</a>, <a href="#rfc.iref.s.5"><b>6.2.2</b></a>, <a href="#rfc.xref.status.101.2">12.2.3</a></li>
    5268                         <li>200 OK&nbsp;&nbsp;<a href="#rfc.xref.status.200.1">6.1</a>, <a href="#rfc.iref.s.7"><b>6.3.1</b></a>, <a href="#rfc.xref.status.200.2">12.2.3</a></li>
    5269                         <li>201 Created&nbsp;&nbsp;<a href="#rfc.xref.status.201.1">6.1</a>, <a href="#rfc.iref.s.8"><b>6.3.2</b></a>, <a href="#rfc.xref.status.201.2">12.2.3</a></li>
    5270                         <li>202 Accepted&nbsp;&nbsp;<a href="#rfc.xref.status.202.1">6.1</a>, <a href="#rfc.iref.s.9"><b>6.3.3</b></a>, <a href="#rfc.xref.status.202.2">12.2.3</a></li>
    5271                         <li>203 Non-Authoritative Information&nbsp;&nbsp;<a href="#rfc.xref.status.203.1">6.1</a>, <a href="#rfc.iref.s.10"><b>6.3.4</b></a>, <a href="#rfc.xref.status.203.2">12.2.3</a>, <a href="#rfc.xref.status.203.3">C</a></li>
    5272                         <li>204 No Content&nbsp;&nbsp;<a href="#rfc.xref.status.204.1">6.1</a>, <a href="#rfc.iref.s.11"><b>6.3.5</b></a>, <a href="#rfc.xref.status.204.2">12.2.3</a></li>
    5273                         <li>205 Reset Content&nbsp;&nbsp;<a href="#rfc.xref.status.205.1">6.1</a>, <a href="#rfc.iref.s.12"><b>6.3.6</b></a>, <a href="#rfc.xref.status.205.2">12.2.3</a></li>
    5274                         <li>300 Multiple Choices&nbsp;&nbsp;<a href="#rfc.xref.status.300.1">6.1</a>, <a href="#rfc.iref.s.14"><b>6.4.1</b></a>, <a href="#rfc.xref.status.300.2">12.2.3</a></li>
    5275                         <li>301 Moved Permanently&nbsp;&nbsp;<a href="#rfc.xref.status.301.1">6.1</a>, <a href="#rfc.iref.s.15"><b>6.4.2</b></a>, <a href="#rfc.xref.status.301.2">12.2.3</a>, <a href="#rfc.xref.status.301.3">C</a></li>
    5276                         <li>302 Found&nbsp;&nbsp;<a href="#rfc.xref.status.302.1">6.1</a>, <a href="#rfc.iref.s.16"><b>6.4.3</b></a>, <a href="#rfc.xref.status.302.2">12.2.3</a>, <a href="#rfc.xref.status.302.3">C</a></li>
    5277                         <li>303 See Other&nbsp;&nbsp;<a href="#rfc.xref.status.303.1">6.1</a>, <a href="#rfc.iref.s.17"><b>6.4.4</b></a>, <a href="#rfc.xref.status.303.2">12.2.3</a></li>
    5278                         <li>305 Use Proxy&nbsp;&nbsp;<a href="#rfc.xref.status.305.1">6.1</a>, <a href="#rfc.iref.s.18"><b>6.4.5</b></a>, <a href="#rfc.xref.status.305.2">12.2.3</a>, <a href="#rfc.xref.status.305.3">C</a></li>
    5279                         <li>306 (Unused)&nbsp;&nbsp;<a href="#rfc.iref.s.19"><b>6.4.6</b></a>, <a href="#rfc.xref.status.306.1">12.2.3</a></li>
    5280                         <li>307 Temporary Redirect&nbsp;&nbsp;<a href="#rfc.xref.status.307.1">6.1</a>, <a href="#rfc.iref.s.20"><b>6.4.7</b></a>, <a href="#rfc.xref.status.307.2">12.2.3</a>, <a href="#rfc.xref.status.307.3">C</a></li>
    5281                         <li>400 Bad Request&nbsp;&nbsp;<a href="#rfc.xref.status.400.1">6.1</a>, <a href="#rfc.iref.s.22"><b>6.5.1</b></a>, <a href="#rfc.xref.status.400.2">12.2.3</a></li>
    5282                         <li>402 Payment Required&nbsp;&nbsp;<a href="#rfc.xref.status.402.1">6.1</a>, <a href="#rfc.iref.s.23"><b>6.5.2</b></a>, <a href="#rfc.xref.status.402.2">12.2.3</a></li>
    5283                         <li>403 Forbidden&nbsp;&nbsp;<a href="#rfc.xref.status.403.1">6.1</a>, <a href="#rfc.iref.s.24"><b>6.5.3</b></a>, <a href="#rfc.xref.status.403.2">12.2.3</a></li>
    5284                         <li>404 Not Found&nbsp;&nbsp;<a href="#rfc.xref.status.404.1">6.1</a>, <a href="#rfc.iref.s.25"><b>6.5.4</b></a>, <a href="#rfc.xref.status.404.2">12.2.3</a></li>
    5285                         <li>405 Method Not Allowed&nbsp;&nbsp;<a href="#rfc.xref.status.405.1">6.1</a>, <a href="#rfc.iref.s.26"><b>6.5.5</b></a>, <a href="#rfc.xref.status.405.2">12.2.3</a></li>
    5286                         <li>406 Not Acceptable&nbsp;&nbsp;<a href="#rfc.xref.status.406.1">6.1</a>, <a href="#rfc.iref.s.27"><b>6.5.6</b></a>, <a href="#rfc.xref.status.406.2">12.2.3</a></li>
    5287                         <li>408 Request Timeout&nbsp;&nbsp;<a href="#rfc.xref.status.408.1">6.1</a>, <a href="#rfc.iref.s.28"><b>6.5.7</b></a>, <a href="#rfc.xref.status.408.2">12.2.3</a></li>
    5288                         <li>409 Conflict&nbsp;&nbsp;<a href="#rfc.xref.status.409.1">6.1</a>, <a href="#rfc.iref.s.29"><b>6.5.8</b></a>, <a href="#rfc.xref.status.409.2">12.2.3</a></li>
    5289                         <li>410 Gone&nbsp;&nbsp;<a href="#rfc.xref.status.410.1">6.1</a>, <a href="#rfc.iref.s.30"><b>6.5.9</b></a>, <a href="#rfc.xref.status.410.2">12.2.3</a></li>
    5290                         <li>411 Length Required&nbsp;&nbsp;<a href="#rfc.xref.status.411.1">6.1</a>, <a href="#rfc.iref.s.31"><b>6.5.10</b></a>, <a href="#rfc.xref.status.411.2">12.2.3</a></li>
    5291                         <li>413 Request Representation Too Large&nbsp;&nbsp;<a href="#rfc.xref.status.413.1">6.1</a>, <a href="#rfc.iref.s.32"><b>6.5.11</b></a>, <a href="#rfc.xref.status.413.2">12.2.3</a></li>
    5292                         <li>414 URI Too Long&nbsp;&nbsp;<a href="#rfc.xref.status.414.1">6.1</a>, <a href="#rfc.iref.s.33"><b>6.5.12</b></a>, <a href="#rfc.xref.status.414.2">12.2.3</a></li>
    5293                         <li>415 Unsupported Media Type&nbsp;&nbsp;<a href="#rfc.xref.status.415.1">6.1</a>, <a href="#rfc.iref.s.34"><b>6.5.13</b></a>, <a href="#rfc.xref.status.415.2">12.2.3</a></li>
    5294                         <li>417 Expectation Failed&nbsp;&nbsp;<a href="#rfc.xref.status.417.1">6.1</a>, <a href="#rfc.iref.s.35"><b>6.5.14</b></a>, <a href="#rfc.xref.status.417.2">12.2.3</a></li>
    5295                         <li>426 Upgrade Required&nbsp;&nbsp;<a href="#rfc.xref.status.426.1">6.1</a>, <a href="#rfc.iref.s.36"><b>6.5.15</b></a>, <a href="#rfc.xref.status.426.2">12.2.3</a>, <a href="#rfc.xref.status.426.3">C</a></li>
    5296                         <li>500 Internal Server Error&nbsp;&nbsp;<a href="#rfc.xref.status.500.1">6.1</a>, <a href="#rfc.iref.s.38"><b>6.6.1</b></a>, <a href="#rfc.xref.status.500.2">12.2.3</a></li>
    5297                         <li>501 Not Implemented&nbsp;&nbsp;<a href="#rfc.xref.status.501.1">6.1</a>, <a href="#rfc.iref.s.39"><b>6.6.2</b></a>, <a href="#rfc.xref.status.501.2">12.2.3</a></li>
    5298                         <li>502 Bad Gateway&nbsp;&nbsp;<a href="#rfc.xref.status.502.1">6.1</a>, <a href="#rfc.iref.s.40"><b>6.6.3</b></a>, <a href="#rfc.xref.status.502.2">12.2.3</a></li>
    5299                         <li>503 Service Unavailable&nbsp;&nbsp;<a href="#rfc.xref.status.503.1">6.1</a>, <a href="#rfc.iref.s.41"><b>6.6.4</b></a>, <a href="#rfc.xref.status.503.2">12.2.3</a></li>
    5300                         <li>504 Gateway Timeout&nbsp;&nbsp;<a href="#rfc.xref.status.504.1">6.1</a>, <a href="#rfc.iref.s.42"><b>6.6.5</b></a>, <a href="#rfc.xref.status.504.2">12.2.3</a></li>
    5301                         <li>505 HTTP Version Not Supported&nbsp;&nbsp;<a href="#rfc.xref.status.505.1">6.1</a>, <a href="#rfc.iref.s.43"><b>6.6.6</b></a>, <a href="#rfc.xref.status.505.2">12.2.3</a></li>
     5265                        <li>100 Continue&nbsp;&nbsp;<a href="#rfc.xref.status.100.1">6.1</a>, <a href="#rfc.iref.s.4"><b>6.2.1</b></a>, <a href="#rfc.xref.status.100.2">11.2.3</a></li>
     5266                        <li>101 Switching Protocols&nbsp;&nbsp;<a href="#rfc.xref.status.101.1">6.1</a>, <a href="#rfc.iref.s.5"><b>6.2.2</b></a>, <a href="#rfc.xref.status.101.2">11.2.3</a></li>
     5267                        <li>200 OK&nbsp;&nbsp;<a href="#rfc.xref.status.200.1">6.1</a>, <a href="#rfc.iref.s.7"><b>6.3.1</b></a>, <a href="#rfc.xref.status.200.2">11.2.3</a></li>
     5268                        <li>201 Created&nbsp;&nbsp;<a href="#rfc.xref.status.201.1">6.1</a>, <a href="#rfc.iref.s.8"><b>6.3.2</b></a>, <a href="#rfc.xref.status.201.2">11.2.3</a></li>
     5269                        <li>202 Accepted&nbsp;&nbsp;<a href="#rfc.xref.status.202.1">6.1</a>, <a href="#rfc.iref.s.9"><b>6.3.3</b></a>, <a href="#rfc.xref.status.202.2">11.2.3</a></li>
     5270                        <li>203 Non-Authoritative Information&nbsp;&nbsp;<a href="#rfc.xref.status.203.1">6.1</a>, <a href="#rfc.iref.s.10"><b>6.3.4</b></a>, <a href="#rfc.xref.status.203.2">11.2.3</a>, <a href="#rfc.xref.status.203.3">C</a></li>
     5271                        <li>204 No Content&nbsp;&nbsp;<a href="#rfc.xref.status.204.1">6.1</a>, <a href="#rfc.iref.s.11"><b>6.3.5</b></a>, <a href="#rfc.xref.status.204.2">11.2.3</a></li>
     5272                        <li>205 Reset Content&nbsp;&nbsp;<a href="#rfc.xref.status.205.1">6.1</a>, <a href="#rfc.iref.s.12"><b>6.3.6</b></a>, <a href="#rfc.xref.status.205.2">11.2.3</a></li>
     5273                        <li>300 Multiple Choices&nbsp;&nbsp;<a href="#rfc.xref.status.300.1">6.1</a>, <a href="#rfc.iref.s.14"><b>6.4.1</b></a>, <a href="#rfc.xref.status.300.2">11.2.3</a></li>
     5274                        <li>301 Moved Permanently&nbsp;&nbsp;<a href="#rfc.xref.status.301.1">6.1</a>, <a href="#rfc.iref.s.15"><b>6.4.2</b></a>, <a href="#rfc.xref.status.301.2">11.2.3</a>, <a href="#rfc.xref.status.301.3">C</a></li>
     5275                        <li>302 Found&nbsp;&nbsp;<a href="#rfc.xref.status.302.1">6.1</a>, <a href="#rfc.iref.s.16"><b>6.4.3</b></a>, <a href="#rfc.xref.status.302.2">11.2.3</a>, <a href="#rfc.xref.status.302.3">C</a></li>
     5276                        <li>303 See Other&nbsp;&nbsp;<a href="#rfc.xref.status.303.1">6.1</a>, <a href="#rfc.iref.s.17"><b>6.4.4</b></a>, <a href="#rfc.xref.status.303.2">11.2.3</a></li>
     5277                        <li>305 Use Proxy&nbsp;&nbsp;<a href="#rfc.xref.status.305.1">6.1</a>, <a href="#rfc.iref.s.18"><b>6.4.5</b></a>, <a href="#rfc.xref.status.305.2">11.2.3</a>, <a href="#rfc.xref.status.305.3">C</a></li>
     5278                        <li>306 (Unused)&nbsp;&nbsp;<a href="#rfc.iref.s.19"><b>6.4.6</b></a>, <a href="#rfc.xref.status.306.1">11.2.3</a></li>
     5279                        <li>307 Temporary Redirect&nbsp;&nbsp;<a href="#rfc.xref.status.307.1">6.1</a>, <a href="#rfc.iref.s.20"><b>6.4.7</b></a>, <a href="#rfc.xref.status.307.2">11.2.3</a>, <a href="#rfc.xref.status.307.3">C</a></li>
     5280                        <li>400 Bad Request&nbsp;&nbsp;<a href="#rfc.xref.status.400.1">6.1</a>, <a href="#rfc.iref.s.22"><b>6.5.1</b></a>, <a href="#rfc.xref.status.400.2">11.2.3</a></li>
     5281                        <li>402 Payment Required&nbsp;&nbsp;<a href="#rfc.xref.status.402.1">6.1</a>, <a href="#rfc.iref.s.23"><b>6.5.2</b></a>, <a href="#rfc.xref.status.402.2">11.2.3</a></li>
     5282                        <li>403 Forbidden&nbsp;&nbsp;<a href="#rfc.xref.status.403.1">6.1</a>, <a href="#rfc.iref.s.24"><b>6.5.3</b></a>, <a href="#rfc.xref.status.403.2">11.2.3</a></li>
     5283                        <li>404 Not Found&nbsp;&nbsp;<a href="#rfc.xref.status.404.1">6.1</a>, <a href="#rfc.iref.s.25"><b>6.5.4</b></a>, <a href="#rfc.xref.status.404.2">11.2.3</a></li>
     5284                        <li>405 Method Not Allowed&nbsp;&nbsp;<a href="#rfc.xref.status.405.1">6.1</a>, <a href="#rfc.iref.s.26"><b>6.5.5</b></a>, <a href="#rfc.xref.status.405.2">11.2.3</a></li>
     5285                        <li>406 Not Acceptable&nbsp;&nbsp;<a href="#rfc.xref.status.406.1">6.1</a>, <a href="#rfc.iref.s.27"><b>6.5.6</b></a>, <a href="#rfc.xref.status.406.2">11.2.3</a></li>
     5286                        <li>408 Request Timeout&nbsp;&nbsp;<a href="#rfc.xref.status.408.1">6.1</a>, <a href="#rfc.iref.s.28"><b>6.5.7</b></a>, <a href="#rfc.xref.status.408.2">11.2.3</a></li>
     5287                        <li>409 Conflict&nbsp;&nbsp;<a href="#rfc.xref.status.409.1">6.1</a>, <a href="#rfc.iref.s.29"><b>6.5.8</b></a>, <a href="#rfc.xref.status.409.2">11.2.3</a></li>
     5288                        <li>410 Gone&nbsp;&nbsp;<a href="#rfc.xref.status.410.1">6.1</a>, <a href="#rfc.iref.s.30"><b>6.5.9</b></a>, <a href="#rfc.xref.status.410.2">11.2.3</a></li>
     5289                        <li>411 Length Required&nbsp;&nbsp;<a href="#rfc.xref.status.411.1">6.1</a>, <a href="#rfc.iref.s.31"><b>6.5.10</b></a>, <a href="#rfc.xref.status.411.2">11.2.3</a></li>
     5290                        <li>413 Request Representation Too Large&nbsp;&nbsp;<a href="#rfc.xref.status.413.1">6.1</a>, <a href="#rfc.iref.s.32"><b>6.5.11</b></a>, <a href="#rfc.xref.status.413.2">11.2.3</a></li>
     5291                        <li>414 URI Too Long&nbsp;&nbsp;<a href="#rfc.xref.status.414.1">6.1</a>, <a href="#rfc.iref.s.33"><b>6.5.12</b></a>, <a href="#rfc.xref.status.414.2">11.2.3</a></li>
     5292                        <li>415 Unsupported Media Type&nbsp;&nbsp;<a href="#rfc.xref.status.415.1">6.1</a>, <a href="#rfc.iref.s.34"><b>6.5.13</b></a>, <a href="#rfc.xref.status.415.2">11.2.3</a></li>
     5293                        <li>417 Expectation Failed&nbsp;&nbsp;<a href="#rfc.xref.status.417.1">6.1</a>, <a href="#rfc.iref.s.35"><b>6.5.14</b></a>, <a href="#rfc.xref.status.417.2">11.2.3</a></li>
     5294                        <li>426 Upgrade Required&nbsp;&nbsp;<a href="#rfc.xref.status.426.1">6.1</a>, <a href="#rfc.iref.s.36"><b>6.5.15</b></a>, <a href="#rfc.xref.status.426.2">11.2.3</a>, <a href="#rfc.xref.status.426.3">C</a></li>
     5295                        <li>500 Internal Server Error&nbsp;&nbsp;<a href="#rfc.xref.status.500.1">6.1</a>, <a href="#rfc.iref.s.38"><b>6.6.1</b></a>, <a href="#rfc.xref.status.500.2">11.2.3</a></li>
     5296                        <li>501 Not Implemented&nbsp;&nbsp;<a href="#rfc.xref.status.501.1">6.1</a>, <a href="#rfc.iref.s.39"><b>6.6.2</b></a>, <a href="#rfc.xref.status.501.2">11.2.3</a></li>
     5297                        <li>502 Bad Gateway&nbsp;&nbsp;<a href="#rfc.xref.status.502.1">6.1</a>, <a href="#rfc.iref.s.40"><b>6.6.3</b></a>, <a href="#rfc.xref.status.502.2">11.2.3</a></li>
     5298                        <li>503 Service Unavailable&nbsp;&nbsp;<a href="#rfc.xref.status.503.1">6.1</a>, <a href="#rfc.iref.s.41"><b>6.6.4</b></a>, <a href="#rfc.xref.status.503.2">11.2.3</a></li>
     5299                        <li>504 Gateway Timeout&nbsp;&nbsp;<a href="#rfc.xref.status.504.1">6.1</a>, <a href="#rfc.iref.s.42"><b>6.6.5</b></a>, <a href="#rfc.xref.status.504.2">11.2.3</a></li>
     5300                        <li>505 HTTP Version Not Supported&nbsp;&nbsp;<a href="#rfc.xref.status.505.1">6.1</a>, <a href="#rfc.iref.s.43"><b>6.6.6</b></a>, <a href="#rfc.xref.status.505.2">11.2.3</a></li>
    53025301                     </ul>
    53035302                  </li>
    … …  
    53115310                     </ul>
    53125311                  </li>
    5313                   <li><em>status-308</em>&nbsp;&nbsp;<a href="#rfc.xref.status-308.1">6.4.7</a>, <a href="#status-308"><b>15.2</b></a></li>
     5312                  <li><em>status-308</em>&nbsp;&nbsp;<a href="#rfc.xref.status-308.1">6.4.7</a>, <a href="#status-308"><b>14.2</b></a></li>
    53145313               </ul>
    53155314            </li>
    53165315            <li><a id="rfc.index.T" href="#rfc.index.T"><b>T</b></a><ul>
    5317                   <li>TRACE method&nbsp;&nbsp;<a href="#rfc.xref.TRACE.1">4.1</a>, <a href="#rfc.iref.t.1"><b>4.3.8</b></a>, <a href="#rfc.xref.TRACE.2">11.14</a>, <a href="#rfc.xref.TRACE.3">12.1.3</a>, <a href="#rfc.xref.TRACE.4">13.1</a></li>
     5316                  <li>TRACE method&nbsp;&nbsp;<a href="#rfc.xref.TRACE.1">4.1</a>, <a href="#rfc.iref.t.1"><b>4.3.8</b></a>, <a href="#rfc.xref.TRACE.2">10.14</a>, <a href="#rfc.xref.TRACE.3">11.1.3</a>, <a href="#rfc.xref.TRACE.4">12.1</a></li>
    53185317               </ul>
    53195318            </li>
    53205319            <li><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul>
    5321                   <li>User-Agent header field&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">5.5</a>, <a href="#rfc.xref.header.user-agent.2">10.1</a>, <a href="#rfc.iref.u.1"><b>11.18</b></a>, <a href="#rfc.xref.header.user-agent.3">12.3.2</a>, <a href="#rfc.xref.header.user-agent.4">13.1</a></li>
     5320                  <li>User-Agent header field&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">3.4.1</a>, <a href="#rfc.xref.header.user-agent.2">5.5</a>, <a href="#rfc.iref.u.1"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3.2</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li>
    53225321               </ul>
    53235322            </li>

  • draft-ietf-httpbis/latest/p2-semantics.xml

    r1853 r1854  
    461461</t>
    462462</section>
     463
     464<section title="Content Negotiation" anchor="content.negotiation">
     465<t>
     466   HTTP responses include a representation which contains information for
     467   interpretation, whether by a human user or for further processing.
     468   Often, the server has different ways of representing the
     469   same information; for example, in different formats, languages,
     470   or using different character encodings.
     471</t>
     472<t>
     473   HTTP clients and their users might have different or variable
     474   capabilities, characteristics or preferences which would influence
     475   which representation, among those available from the server,
     476   would be best for the server to deliver. For this reason, HTTP
     477   provides mechanisms for "content negotiation" &mdash; a process of
     478   allowing selection of a representation of a given resource,
     479   when more than one is available.
     480</t>
     481<t>
     482   This specification defines two patterns of content negotiation;
     483   "server-driven", where the server selects the representation based
     484   upon the client's stated preferences, and "agent-driven" negotiation,
     485   where the server provides a list of representations for the client to
     486   choose from, based upon their metadata. In addition,  there are
     487   other patterns: some applications use an "active content" pattern,
     488   where the server returns active content which runs on the client
     489   and, based on client available parameters, selects additional
     490   resources to invoke. "Transparent Content Negotiation" (<xref target="RFC2295"/>)
     491   has also been proposed.
     492</t>
     493<t>
     494   These patterns are all widely used, and have trade-offs in applicability
     495   and practicality. In particular, when the number of preferences or
     496   capabilities to be expressed by a client are large (such as when many
     497   different formats are supported by a user-agent), server-driven
     498   negotiation becomes unwieldy, and might not be appropriate. Conversely,
     499   when the number of representations to choose from is very large,
     500   agent-driven negotiation might not be appropriate.
     501</t>
     502<t>
     503   Note that, in all cases, the supplier of representations has the
     504   responsibility for determining which representations might be
     505   considered to be the "same information".
     506</t>
     507
     508<section title="Server-driven Negotiation" anchor="server-driven.negotiation">
     509<t>
     510   If the selection of the best representation for a response is made by
     511   an algorithm located at the server, it is called server-driven
     512   negotiation. Selection is based on the available representations of
     513   the response (the dimensions over which it can vary; e.g., language,
     514   content-coding, etc.) and the contents of particular header fields in
     515   the request message or on other information pertaining to the request
     516   (such as the network address of the client).
     517</t>
     518<t>
     519   Server-driven negotiation is advantageous when the algorithm for
     520   selecting from among the available representations is difficult to
     521   describe to the user agent, or when the server desires to send its
     522   "best guess" to the client along with the first response (hoping to
     523   avoid the round-trip delay of a subsequent request if the "best
     524   guess" is good enough for the user). In order to improve the server's
     525   guess, the user agent &MAY; include request header fields (<x:ref>Accept</x:ref>,
     526   <x:ref>Accept-Language</x:ref>, <x:ref>Accept-Encoding</x:ref>, etc.) which describe its
     527   preferences for such a response.
     528</t>
     529<t>
     530   Server-driven negotiation has disadvantages:
     531  <list style="numbers">
     532    <t>
     533         It is impossible for the server to accurately determine what
     534         might be "best" for any given user, since that would require
     535         complete knowledge of both the capabilities of the user agent
     536         and the intended use for the response (e.g., does the user want
     537         to view it on screen or print it on paper?).
     538    </t>
     539    <t>
     540         Having the user agent describe its capabilities in every
     541         request can be both very inefficient (given that only a small
     542         percentage of responses have multiple representations) and a
     543         potential violation of the user's privacy.
     544    </t>
     545    <t>
     546         It complicates the implementation of an origin server and the
     547         algorithms for generating responses to a request.
     548    </t>
     549    <t>
     550         It might limit a public cache's ability to use the same response
     551         for multiple user's requests.
     552    </t>
     553  </list>
     554</t>
     555<t>
     556   Server-driven negotiation allows the user agent to specify its preferences,
     557   but it cannot expect responses to always honor them. For example, the origin
     558   server might not implement server-driven negotiation, or it might decide that
     559   sending a response that doesn't conform to them is better than sending a <x:ref>406
     560   (Not Acceptable)</x:ref> response.
     561</t>
     562<t>
     563   HTTP/1.1 includes the following header fields for enabling
     564   server-driven negotiation through description of user agent
     565   capabilities and user preferences: <x:ref>Accept</x:ref>
     566   (<xref target="header.accept"/>), <x:ref>Accept-Charset</x:ref>
     567   (<xref target="header.accept-charset"/>), <x:ref>Accept-Encoding</x:ref>
     568   (<xref target="header.accept-encoding"/>), <x:ref>Accept-Language</x:ref>
     569   (<xref target="header.accept-language"/>), and <x:ref>User-Agent</x:ref>
     570   (&header-user-agent;).
     571   However, an origin server is not limited to these dimensions and &MAY; vary
     572   the response based on any aspect of the request, including aspects
     573   of the connection (e.g., IP address) or information within extension
     574   header fields not defined by this specification.
     575</t>
     576<x:note>
     577  <t>
     578    &Note; In practice, <x:ref>User-Agent</x:ref> based negotiation is fragile,
     579    because new clients might not be recognized.
     580  </t>
     581</x:note>
     582<t>
     583   The <x:ref>Vary</x:ref> header field (&header-vary;) can be used to express
     584   the parameters the server uses to select a representation that is subject to
     585   server-driven negotiation.
     586</t>
     587</section>
     588
     589<section title="Agent-driven Negotiation" anchor="agent-driven.negotiation">
     590<t>
     591   With agent-driven negotiation, selection of the best representation
     592   for a response is performed by the user agent after receiving an
     593   initial response from the origin server. Selection is based on a list
     594   of the available representations of the response included within the
     595   header fields or body of the initial response, with each
     596   representation identified by its own URI. Selection from among the
     597   representations can be performed automatically (if the user agent is
     598   capable of doing so) or manually by the user selecting from a
     599   generated (possibly hypertext) menu.
     600</t>
     601<t>
     602   Agent-driven negotiation is advantageous when the response would vary
     603   over commonly-used dimensions (such as type, language, or encoding),
     604   when the origin server is unable to determine a user agent's
     605   capabilities from examining the request, and generally when public
     606   caches are used to distribute server load and reduce network usage.
     607</t>
     608<t>
     609   Agent-driven negotiation suffers from the disadvantage of needing a
     610   second request to obtain the best alternate representation. This
     611   second request is only efficient when caching is used. In addition,
     612   this specification does not define any mechanism for supporting
     613   automatic selection, though it also does not prevent any such
     614   mechanism from being developed as an extension and used within
     615   HTTP/1.1.
     616</t>
     617<t>
     618   This specification defines the <x:ref>300 (Multiple Choices)</x:ref> and
     619   <x:ref>406 (Not Acceptable)</x:ref> status codes for enabling agent-driven
     620   negotiation when the server is unwilling or unable to provide a varying
     621   response using server-driven negotiation.
     622</t>
     623</section>
     624
     625<section title="Quality Values" anchor="quality.values">
     626  <x:anchor-alias value="weight"/>
     627  <x:anchor-alias value="qvalue"/>
     628<t>
     629   Many of the request header fields for server-driven content negotiation
     630   use a common parameter, named "q", to assign a relative "weight" to the
     631   preference for that associated kind of content.
     632   This weight is referred to as a "quality value" (or "qvalue") because
     633   the same parameter name is often used within server configurations to
     634   assign a weight to the relative quality of the various representations
     635   that can be selected for a resource.
     636</t>
     637<t>
     638   The weight is normalized to a real number in the range 0 through 1,
     639   where 0.001 is the least preferred and 1 is the most preferred;
     640   a value of 0 means "not acceptable". If no "q" parameter is present,
     641   the default weight is 1.
     642</t>
     643<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="weight"/><iref primary="true" item="Grammar" subitem="qvalue"/>
     644  <x:ref>weight</x:ref> = <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref>
     645  <x:ref>qvalue</x:ref> = ( "0" [ "." 0*3<x:ref>DIGIT</x:ref> ] )
     646         / ( "1" [ "." 0*3("0") ] )
     647</artwork></figure>
     648<t>
     649   A sender of qvalue &MUST-NOT; generate more than three digits after the
     650   decimal point. User configuration of these values ought to be limited in
     651   the same fashion.
     652</t>
     653</section>
     654</section>
    463655</section>
    464656
    … …  
    26882880   from the message body by decoding any <x:ref>Transfer-Encoding</x:ref> that
    26892881   might have been applied to ensure safe and proper transfer of the message.
    2690 </t>
    2691 </section>
    2692 </section>
    2693 
    2694 <section title="Content Negotiation" anchor="content.negotiation">
    2695 <t>
    2696    HTTP responses include a representation which contains information for
    2697    interpretation, whether by a human user or for further processing.
    2698    Often, the server has different ways of representing the
    2699    same information; for example, in different formats, languages,
    2700    or using different character encodings.
    2701 </t>
    2702 <t>
    2703    HTTP clients and their users might have different or variable
    2704    capabilities, characteristics or preferences which would influence
    2705    which representation, among those available from the server,
    2706    would be best for the server to deliver. For this reason, HTTP
    2707    provides mechanisms for "content negotiation" &mdash; a process of
    2708    allowing selection of a representation of a given resource,
    2709    when more than one is available.
    2710 </t>
    2711 <t>
    2712    This specification defines two patterns of content negotiation;
    2713    "server-driven", where the server selects the representation based
    2714    upon the client's stated preferences, and "agent-driven" negotiation,
    2715    where the server provides a list of representations for the client to
    2716    choose from, based upon their metadata. In addition,  there are
    2717    other patterns: some applications use an "active content" pattern,
    2718    where the server returns active content which runs on the client
    2719    and, based on client available parameters, selects additional
    2720    resources to invoke. "Transparent Content Negotiation" (<xref target="RFC2295"/>)
    2721    has also been proposed.
    2722 </t>
    2723 <t>
    2724    These patterns are all widely used, and have trade-offs in applicability
    2725    and practicality. In particular, when the number of preferences or
    2726    capabilities to be expressed by a client are large (such as when many
    2727    different formats are supported by a user-agent), server-driven
    2728    negotiation becomes unwieldy, and might not be appropriate. Conversely,
    2729    when the number of representations to choose from is very large,
    2730    agent-driven negotiation might not be appropriate.
    2731 </t>
    2732 <t>
    2733    Note that, in all cases, the supplier of representations has the
    2734    responsibility for determining which representations might be
    2735    considered to be the "same information".
    2736 </t>
    2737 
    2738 <section title="Server-driven Negotiation" anchor="server-driven.negotiation">
    2739 <t>
    2740    If the selection of the best representation for a response is made by
    2741    an algorithm located at the server, it is called server-driven
    2742    negotiation. Selection is based on the available representations of
    2743    the response (the dimensions over which it can vary; e.g., language,
    2744    content-coding, etc.) and the contents of particular header fields in
    2745    the request message or on other information pertaining to the request
    2746    (such as the network address of the client).
    2747 </t>
    2748 <t>
    2749    Server-driven negotiation is advantageous when the algorithm for
    2750    selecting from among the available representations is difficult to
    2751    describe to the user agent, or when the server desires to send its
    2752    "best guess" to the client along with the first response (hoping to
    2753    avoid the round-trip delay of a subsequent request if the "best
    2754    guess" is good enough for the user). In order to improve the server's
    2755    guess, the user agent &MAY; include request header fields (<x:ref>Accept</x:ref>,
    2756    <x:ref>Accept-Language</x:ref>, <x:ref>Accept-Encoding</x:ref>, etc.) which describe its
    2757    preferences for such a response.
    2758 </t>
    2759 <t>
    2760    Server-driven negotiation has disadvantages:
    2761   <list style="numbers">
    2762     <t>
    2763          It is impossible for the server to accurately determine what
    2764          might be "best" for any given user, since that would require
    2765          complete knowledge of both the capabilities of the user agent
    2766          and the intended use for the response (e.g., does the user want
    2767          to view it on screen or print it on paper?).
    2768     </t>
    2769     <t>
    2770          Having the user agent describe its capabilities in every
    2771          request can be both very inefficient (given that only a small
    2772          percentage of responses have multiple representations) and a
    2773          potential violation of the user's privacy.
    2774     </t>
    2775     <t>
    2776          It complicates the implementation of an origin server and the
    2777          algorithms for generating responses to a request.
    2778     </t>
    2779     <t>
    2780          It might limit a public cache's ability to use the same response
    2781          for multiple user's requests.
    2782     </t>
    2783   </list>
    2784 </t>
    2785 <t>
    2786    Server-driven negotiation allows the user agent to specify its preferences,
    2787    but it cannot expect responses to always honor them. For example, the origin
    2788    server might not implement server-driven negotiation, or it might decide that
    2789    sending a response that doesn't conform to them is better than sending a <x:ref>406
    2790    (Not Acceptable)</x:ref> response.
    2791 </t>
    2792 <t>
    2793    HTTP/1.1 includes the following header fields for enabling
    2794    server-driven negotiation through description of user agent
    2795    capabilities and user preferences: <x:ref>Accept</x:ref>
    2796    (<xref target="header.accept"/>), <x:ref>Accept-Charset</x:ref>
    2797    (<xref target="header.accept-charset"/>), <x:ref>Accept-Encoding</x:ref>
    2798    (<xref target="header.accept-encoding"/>), <x:ref>Accept-Language</x:ref>
    2799    (<xref target="header.accept-language"/>), and <x:ref>User-Agent</x:ref>
    2800    (&header-user-agent;).
    2801    However, an origin server is not limited to these dimensions and &MAY; vary
    2802    the response based on any aspect of the request, including aspects
    2803    of the connection (e.g., IP address) or information within extension
    2804    header fields not defined by this specification.
    2805 </t>
    2806 <x:note>
    2807   <t>
    2808     &Note; In practice, <x:ref>User-Agent</x:ref> based negotiation is fragile,
    2809     because new clients might not be recognized.
    2810   </t>
    2811 </x:note>
    2812 <t>
    2813    The <x:ref>Vary</x:ref> header field (&header-vary;) can be used to express
    2814    the parameters the server uses to select a representation that is subject to
    2815    server-driven negotiation.
    2816 </t>
    2817 </section>
    2818 
    2819 <section title="Agent-driven Negotiation" anchor="agent-driven.negotiation">
    2820 <t>
    2821    With agent-driven negotiation, selection of the best representation
    2822    for a response is performed by the user agent after receiving an
    2823    initial response from the origin server. Selection is based on a list
    2824    of the available representations of the response included within the
    2825    header fields or body of the initial response, with each
    2826    representation identified by its own URI. Selection from among the
    2827    representations can be performed automatically (if the user agent is
    2828    capable of doing so) or manually by the user selecting from a
    2829    generated (possibly hypertext) menu.
    2830 </t>
    2831 <t>
    2832    Agent-driven negotiation is advantageous when the response would vary
    2833    over commonly-used dimensions (such as type, language, or encoding),
    2834    when the origin server is unable to determine a user agent's
    2835    capabilities from examining the request, and generally when public
    2836    caches are used to distribute server load and reduce network usage.
    2837 </t>
    2838 <t>
    2839    Agent-driven negotiation suffers from the disadvantage of needing a
    2840    second request to obtain the best alternate representation. This
    2841    second request is only efficient when caching is used. In addition,
    2842    this specification does not define any mechanism for supporting
    2843    automatic selection, though it also does not prevent any such
    2844    mechanism from being developed as an extension and used within
    2845    HTTP/1.1.
    2846 </t>
    2847 <t>
    2848    This specification defines the <x:ref>300 (Multiple Choices)</x:ref> and
    2849    <x:ref>406 (Not Acceptable)</x:ref> status codes for enabling agent-driven
    2850    negotiation when the server is unwilling or unable to provide a varying
    2851    response using server-driven negotiation.
    2852 </t>
    2853 </section>
    2854 
    2855 <section title="Quality Values" anchor="quality.values">
    2856   <x:anchor-alias value="weight"/>
    2857   <x:anchor-alias value="qvalue"/>
    2858 <t>
    2859    Many of the request header fields for server-driven content negotiation
    2860    use a common parameter, named "q", to assign a relative "weight" to the
    2861    preference for that associated kind of content.
    2862    This weight is referred to as a "quality value" (or "qvalue") because
    2863    the same parameter name is often used within server configurations to
    2864    assign a weight to the relative quality of the various representations
    2865    that can be selected for a resource.
    2866 </t>
    2867 <t>
    2868    The weight is normalized to a real number in the range 0 through 1,
    2869    where 0.001 is the least preferred and 1 is the most preferred;
    2870    a value of 0 means "not acceptable". If no "q" parameter is present,
    2871    the default weight is 1.
    2872 </t>
    2873 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="weight"/><iref primary="true" item="Grammar" subitem="qvalue"/>
    2874   <x:ref>weight</x:ref> = <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref>
    2875   <x:ref>qvalue</x:ref> = ( "0" [ "." 0*3<x:ref>DIGIT</x:ref> ] )
    2876          / ( "1" [ "." 0*3("0") ] )
    2877 </artwork></figure>
    2878 <t>
    2879    A sender of qvalue &MUST-NOT; generate more than three digits after the
    2880    decimal point. User configuration of these values ought to be limited in
    2881    the same fashion.
    28822882</t>
    28832883</section>
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