Changeset 1847


Ignore:
Timestamp:
02/09/12 05:22:28 (9 years ago)
Author:
fielding@…
Message:

(editorial) make header field registry consistent with others by moving considerations for new fields down to registrations

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

Legend:

Unmodified
Added
Removed

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

    r1846 r1847  
    612612               <li><a href="#rfc.section.4.3">4.3</a>&nbsp;&nbsp;&nbsp;<a href="#resource.fields">Resource Metadata Fields</a></li>
    613613               <li><a href="#rfc.section.4.4">4.4</a>&nbsp;&nbsp;&nbsp;<a href="#payload.fields">Payload Metadata Fields</a></li>
    614                <li><a href="#rfc.section.4.5">4.5</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.creating.header.fields">Considerations for Creating Header Fields</a></li>
    615                <li><a href="#rfc.section.4.6">4.6</a>&nbsp;&nbsp;&nbsp;<a href="#request.header.fields">Request Header Fields</a></li>
    616                <li><a href="#rfc.section.4.7">4.7</a>&nbsp;&nbsp;&nbsp;<a href="#response.header.fields">Response Header Fields</a></li>
     614               <li><a href="#rfc.section.4.5">4.5</a>&nbsp;&nbsp;&nbsp;<a href="#request.header.fields">Request Header Fields</a></li>
     615               <li><a href="#rfc.section.4.6">4.6</a>&nbsp;&nbsp;&nbsp;<a href="#response.header.fields">Response Header Fields</a></li>
    617616            </ul>
    618617         </li>
    … …  
    736735                  </ul>
    737736               </li>
    738                <li><a href="#rfc.section.11.3">11.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Header Field Registration</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>
     740                  </ul>
     741               </li>
    739742               <li><a href="#rfc.section.11.4">11.4</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.registry">Content Coding Registry</a><ul>
    740743                     <li><a href="#rfc.section.11.4.1">11.4.1</a>&nbsp;&nbsp;&nbsp;<a href="#content.coding.procedure">Procedure</a></li>
    … …  
    12041207      <h2 id="rfc.section.4.3"><a href="#rfc.section.4.3">4.3</a>&nbsp;<a id="resource.fields" href="#resource.fields">Resource Metadata Fields</a></h2>
    12051208      <h2 id="rfc.section.4.4"><a href="#rfc.section.4.4">4.4</a>&nbsp;<a id="payload.fields" href="#payload.fields">Payload Metadata Fields</a></h2>
    1206       <h2 id="rfc.section.4.5"><a href="#rfc.section.4.5">4.5</a>&nbsp;<a id="considerations.for.creating.header.fields" href="#considerations.for.creating.header.fields">Considerations for Creating Header Fields</a></h2>
    1207       <p id="rfc.section.4.5.p.1">New header fields are registered using the procedures described in <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>.
    1208       </p>
    1209       <p id="rfc.section.4.5.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
    1210          with "X-" if they are to be registered (either immediately or in the future).
    1211       </p>
    1212       <p id="rfc.section.4.5.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.Part1.12"><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
    1213          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>.
    1214       </p>
    1215       <p id="rfc.section.4.5.p.4">Because commas (",") are used as a generic delimiter between field-values, they need to be treated with care if they are allowed
    1216          in the field-value's payload. Typically, components that might contain a comma are protected with double-quotes using the
    1217          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.Part1.13"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    1218       </p>
    1219       <p id="rfc.section.4.5.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
    1220          these:
    1221       </p>
    1222       <div id="rfc.figure.u.4"></div><pre class="text">  Example-URI-Field: "http://example.com/a.html,foo",
    1223                      "http://without-a-comma.example.com/"
    1224   Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005"
    1225 </pre><p id="rfc.section.4.5.p.7">Note that double quote delimiters almost always are used with the quoted-string production; using a different syntax inside
    1226          double quotes will likely cause unnecessary confusion.
    1227       </p>
    1228       <p id="rfc.section.4.5.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.1" 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
    1229          parser components. When allowing both forms, the meaning of a parameter value ought to be independent of the syntax used for
    1230          it (for an example, see the notes on parameter handling for media types in <a href="#media.types" title="Media Types">Section&nbsp;6.5</a>).
    1231       </p>
    1232       <p id="rfc.section.4.5.p.9">Authors of specifications defining new header fields are advised to consider documenting: </p>
    1233       <ul>
    1234          <li>
    1235             <p>Whether the field is a single value, or whether it can be a list (delimited by commas; see <a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.14"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    1236             </p>
    1237             <p>If it does not use the list syntax, document how to treat messages where the header field occurs multiple times (a sensible
    1238                default would be to ignore the header field, but this might not always be the right choice).
    1239             </p>
    1240             <p>Note that intermediaries and software libraries might combine multiple header field instances into a single one, despite the
    1241                header field not allowing this. A robust format enables recipients to discover these situations (good example: "Content-Type",
    1242                as the comma can only appear inside quoted strings; bad example: "Location", as a comma can occur inside a URI).
    1243             </p>
    1244          </li>
    1245          <li>
    1246             <p>Under what conditions the header field can be used; e.g., only in responses or requests, in all messages, only on responses
    1247                to a particular request method.
    1248             </p>
    1249          </li>
    1250          <li>
    1251             <p>Whether it is appropriate to list the field-name in the <a href="p1-messaging.html#header.connection" class="smpl">Connection</a> header field (i.e., if the header field is to be hop-by-hop, see <a href="p1-messaging.html#header.connection" title="Connection">Section 6.1</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>).
    1252             </p>
    1253          </li>
    1254          <li>
    1255             <p>Under what conditions intermediaries are allowed to modify the header field's value, insert or delete it.</p>
    1256          </li>
    1257          <li>
    1258             <p>How the header field might interact with caching (see <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    1259             </p>
    1260          </li>
    1261          <li>
    1262             <p>Whether the header field is useful or allowable in trailers (see <a href="p1-messaging.html#chunked.encoding" title="Chunked Transfer Coding">Section 4.1</a> of <a href="#Part1" id="rfc.xref.Part1.16"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    1263             </p>
    1264          </li>
    1265          <li>
    1266             <p>Whether the header field ought to be preserved across redirects.</p>
    1267          </li>
    1268       </ul>
    1269       <h2 id="rfc.section.4.6"><a href="#rfc.section.4.6">4.6</a>&nbsp;<a id="request.header.fields" href="#request.header.fields">Request Header Fields</a></h2>
    1270       <p id="rfc.section.4.6.p.1">The request header fields allow the client to pass additional information about the request, and about the client itself,
     1209      <h2 id="rfc.section.4.5"><a href="#rfc.section.4.5">4.5</a>&nbsp;<a id="request.header.fields" href="#request.header.fields">Request Header Fields</a></h2>
     1210      <p id="rfc.section.4.5.p.1">The request header fields allow the client to pass additional information about the request, and about the client itself,
    12711211         to the server. These fields act as request modifiers, with semantics equivalent to the parameters on a programming language
    12721212         method invocation.
    … …  
    13111251               <tr>
    13121252                  <td class="left">Host</td>
    1313                   <td class="left"><a href="p1-messaging.html#header.host" title="Host">Section 5.4</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></td>
     1253                  <td class="left"><a href="p1-messaging.html#header.host" title="Host">Section 5.4</a> of <a href="#Part1" id="rfc.xref.Part1.12"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a></td>
    13141254               </tr>
    13151255               <tr>
    … …  
    13511291               <tr>
    13521292                  <td class="left">TE</td>
    1353                   <td class="left"><a href="p1-messaging.html#header.te" title="TE">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.18"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a></td>
     1293                  <td class="left"><a href="p1-messaging.html#header.te" title="TE">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.13"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a></td>
    13541294               </tr>
    13551295               <tr>
    … …  
    13601300         </table>
    13611301      </div>
    1362       <h2 id="rfc.section.4.7"><a href="#rfc.section.4.7">4.7</a>&nbsp;<a id="response.header.fields" href="#response.header.fields">Response Header Fields</a></h2>
    1363       <p id="rfc.section.4.7.p.1">The response header fields allow the server to pass additional information about the response which cannot be placed in the
    1364          status-line. These header fields give information about the server and about further access to the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</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>).
     1302      <h2 id="rfc.section.4.6"><a href="#rfc.section.4.6">4.6</a>&nbsp;<a id="response.header.fields" href="#response.header.fields">Response Header Fields</a></h2>
     1303      <p id="rfc.section.4.6.p.1">The response header fields allow the server to pass additional information about the response which cannot be placed in the
     1304         status-line. These header fields give information about the server and about further access to the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.14"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    13651305      </p>
    13661306      <div id="rfc.table.u.2">
    … …  
    13791319               <tr>
    13801320                  <td class="left">Age</td>
    1381                   <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 7.1</a> of <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
     1321                  <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 7.1</a> of <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
    13821322               </tr>
    13831323               <tr>
    … …  
    14111351               <tr>
    14121352                  <td class="left">Vary</td>
    1413                   <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
     1353                  <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
    14141354               </tr>
    14151355               <tr>
    … …  
    14431383         </li>
    14441384      </ul>
    1445       <p id="rfc.section.5.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>).
     1385      <p id="rfc.section.5.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.1" title="Content-Type">Section&nbsp;10.9</a>).
    14461386      </p>
    14471387      <h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a>&nbsp;<a id="overview.of.status.codes" href="#overview.of.status.codes">Overview of Status Codes</a></h2>
    … …  
    16871627      <p id="rfc.section.5.2.1.p.1">The client <em class="bcp14">SHOULD</em> continue with its request. This interim response is used to inform the client that the initial part of the request has been
    16881628         received and has not yet been rejected by the server. The client <em class="bcp14">SHOULD</em> continue by sending the remainder of the request or, if the request has already been completed, ignore this response. The
    1689          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.Part1.20"><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.
     1629         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.
    16901630      </p>
    16911631      <div id="rfc.iref.23"></div>
    16921632      <div id="rfc.iref.s.4"></div>
    16931633      <h3 id="rfc.section.5.2.2"><a href="#rfc.section.5.2.2">5.2.2</a>&nbsp;<a id="status.101" href="#status.101">101 Switching Protocols</a></h3>
    1694       <p id="rfc.section.5.2.2.p.1">The server understands and is willing to comply with the client's request, via the <a href="p1-messaging.html#header.upgrade" class="smpl">Upgrade</a> message header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 6.4</a> of <a href="#Part1" id="rfc.xref.Part1.21"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>), for a change in the application protocol being used on this connection. The server will switch protocols to those defined
     1634      <p id="rfc.section.5.2.2.p.1">The server understands and is willing to comply with the client's request, via the <a href="p1-messaging.html#header.upgrade" class="smpl">Upgrade</a> message header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 6.4</a> of <a href="#Part1" id="rfc.xref.Part1.16"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>), for a change in the application protocol being used on this connection. The server will switch protocols to those defined
    16951635         by the response's Upgrade header field immediately after the empty line which terminates the 101 response.
    16961636      </p>
    … …  
    17171657         <dd>a representation containing the request message as received by the end server.</dd>
    17181658      </dl>
    1719       <p id="rfc.section.5.3.1.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.Part6.10"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 200 responses.
     1659      <p id="rfc.section.5.3.1.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.
    17201660      </p>
    17211661      <div id="rfc.iref.26"></div>
    … …  
    17471687      <div id="rfc.iref.s.9"></div>
    17481688      <h3 id="rfc.section.5.3.4"><a href="#rfc.section.5.3.4">5.3.4</a>&nbsp;<a id="status.203" href="#status.203">203 Non-Authoritative Information</a></h3>
    1749       <p id="rfc.section.5.3.4.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.Part1.22"><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.Part6.11"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1689      <p id="rfc.section.5.3.4.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>).
    17501690      </p>
    17511691      <p id="rfc.section.5.3.4.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
    1752          (<a href="p6-cache.html#header.warning" title="Warning">Section 7.6</a> of <a href="#Part6" id="rfc.xref.Part6.12"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) is appropriate.
    1753       </p>
    1754       <p id="rfc.section.5.3.4.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.Part6.13"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 203 responses.
     1692         (<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.
     1693      </p>
     1694      <p id="rfc.section.5.3.4.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.
    17551695      </p>
    17561696      <div id="rfc.iref.29"></div>
    … …  
    17821722         another input action.
    17831723      </p>
    1784       <p id="rfc.section.5.3.6.p.2">The message body included with the response <em class="bcp14">MUST</em> be empty. Note that receivers still need to parse the response according to the algorithm defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.23"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
     1724      <p id="rfc.section.5.3.6.p.2">The message body included with the response <em class="bcp14">MUST</em> be empty. Note that receivers still need to parse the response according to the algorithm defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.18"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
    17851725      </p>
    17861726      <h2 id="rfc.section.5.4"><a href="#rfc.section.5.4">5.4</a>&nbsp;<a id="status.3xx" href="#status.3xx">Redirection 3xx</a></h2>
    … …  
    18441784      <p id="rfc.section.5.4.1.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.
    18451785      </p>
    1846       <p id="rfc.section.5.4.1.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.Part6.14"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 300 responses.
     1786      <p id="rfc.section.5.4.1.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.
    18471787      </p>
    18481788      <div id="rfc.iref.33"></div>
    … …  
    18521792         request URI to one or more of the new references returned by the server, where possible.
    18531793      </p>
    1854       <p id="rfc.section.5.4.2.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.Part6.15"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 301 responses.
     1794      <p id="rfc.section.5.4.2.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.
    18551795      </p>
    18561796      <p id="rfc.section.5.4.2.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).
    … …  
    20011941         — that is left to the discretion of the server owner.
    20021942      </p>
    2003       <p id="rfc.section.5.5.9.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.Part6.16"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 410 responses.
     1943      <p id="rfc.section.5.5.9.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.
    20041944      </p>
    20051945      <div id="rfc.iref.49"></div>
    … …  
    20411981      <div id="rfc.iref.s.35"></div>
    20421982      <h3 id="rfc.section.5.5.15"><a href="#rfc.section.5.5.15">5.5.15</a>&nbsp;<a id="status.426" href="#status.426">426 Upgrade Required</a></h3>
    2043       <p id="rfc.section.5.5.15.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.Part1.24"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>) specifying the required protocols.
    2044       </p>
    2045       <div id="rfc.figure.u.5"></div>
     1983      <p id="rfc.section.5.5.15.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.
     1984      </p>
     1985      <div id="rfc.figure.u.4"></div>
    20461986      <p>Example:</p>  <pre class="text">HTTP/1.1 426 Upgrade Required
    20471987Upgrade: HTTP/3.0
    … …  
    21062046      <p id="rfc.section.5.6.6.p.1">The server does not support, or refuses to support, the protocol version that was used in the request message. The server
    21072047         is indicating that it is unable or unwilling to complete the request using the same major version as the client, as described
    2108          in <a href="p1-messaging.html#http.version" title="Protocol Versioning">Section 2.6</a> of <a href="#Part1" id="rfc.xref.Part1.25"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>, other than with this error message. The response <em class="bcp14">SHOULD</em> contain a representation describing why that version is not supported and what other protocols are supported by that server.
     2048         in <a href="p1-messaging.html#http.version" title="Protocol Versioning">Section 2.6</a> of <a href="#Part1" id="rfc.xref.Part1.20"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>, other than with this error message. The response <em class="bcp14">SHOULD</em> contain a representation describing why that version is not supported and what other protocols are supported by that server.
    21092049      </p>
    21102050      <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h1>
    … …  
    21132053         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>:
    21142054      </p>
    2115       <div id="rfc.figure.u.6"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
     2055      <div id="rfc.figure.u.5"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
    21162056</pre><p id="rfc.section.6.1.p.3">The other formats are described here only for compatibility with obsolete implementations.</p>
    2117       <div id="rfc.figure.u.7"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
     2057      <div id="rfc.figure.u.6"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
    21182058Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
    21192059</pre><p id="rfc.section.6.1.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.
    … …  
    21232063         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.
    21242064      </p>
    2125       <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>
     2065      <div id="rfc.figure.u.7"></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>
    21262066</pre><div id="preferred.date.format">
    21272067         <p id="rfc.section.6.1.p.8">                    Preferred format:</p>
    21282068      </div>
    2129       <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>
     2069      <div id="rfc.figure.u.8"></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>
    21302070  ; fixed length subset of the format defined in
    21312071  ; <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>
    … …  
    21702110         <p id="rfc.section.6.1.p.11">              Obsolete formats:</p>
    21712111      </div>
    2172       <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>
    2173 </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>
     2112      <div id="rfc.figure.u.9"></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>
     2113</pre><div id="rfc.figure.u.10"></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>
    21742114  <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>
    21752115                 ; day-month-year (e.g., 02-Jun-82)
    … …  
    21822122         / %x53.61.74.75.72.64.61.79 ; "Saturday", case-sensitive
    21832123         / %x53.75.6E.64.61.79 ; "Sunday", case-sensitive
    2184 </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>
     2124</pre><div id="rfc.figure.u.11"></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>
    21852125  <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> ))
    21862126                 ; month day (e.g., Jun  2)
    … …  
    22002140         By convention, the products are listed in order of their significance for identifying the application.
    22012141      </p>
    2202       <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>]
     2142      <div id="rfc.figure.u.12"></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>]
    22032143  <a href="#product.tokens" class="smpl">product-version</a> = <a href="#imported.abnf" class="smpl">token</a>
    22042144</pre><p id="rfc.section.6.2.p.3">Examples:</p>
    2205       <div id="rfc.figure.u.14"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
     2145      <div id="rfc.figure.u.13"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    22062146  Server: Apache/0.8.4
    22072147</pre><p id="rfc.section.6.2.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).
    … …  
    22142154         </p>
    22152155      </div>
    2216       <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>
     2156      <div id="rfc.figure.u.14"></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>
    22172157</pre><p id="rfc.section.6.3.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
    22182158         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.
    … …  
    22282168         directly, and only decoded by the recipient.
    22292169      </p>
    2230       <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>
     2170      <div id="rfc.figure.u.15"></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>
    22312171</pre><p id="rfc.section.6.4.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;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.1" 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
    22322172         mechanism will be required to remove the encoding.
    … …  
    22352175      </p>
    22362176      <ul class="empty">
    2237          <li>See <a href="p1-messaging.html#compress.coding" title="Compress Coding">Section 4.2.1</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>.
     2177         <li>See <a href="p1-messaging.html#compress.coding" title="Compress Coding">Section 4.2.1</a> of <a href="#Part1" id="rfc.xref.Part1.21"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
    22382178         </li>
    22392179      </ul>
    … …  
    22412181      </p>
    22422182      <ul class="empty">
    2243          <li>See <a href="p1-messaging.html#deflate.coding" title="Deflate Coding">Section 4.2.2</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>.
     2183         <li>See <a href="p1-messaging.html#deflate.coding" title="Deflate Coding">Section 4.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.22"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
    22442184         </li>
    22452185      </ul>
    … …  
    22472187      </p>
    22482188      <ul class="empty">
    2249          <li>See <a href="p1-messaging.html#gzip.coding" title="Gzip Coding">Section 4.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.28"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
     2189         <li>See <a href="p1-messaging.html#gzip.coding" title="Gzip Coding">Section 4.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.23"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
    22502190         </li>
    22512191      </ul>
    22522192      <h2 id="rfc.section.6.5"><a href="#rfc.section.6.5">6.5</a>&nbsp;<a id="media.types" href="#media.types">Media Types</a></h2>
    2253       <p id="rfc.section.6.5.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.1"><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.2" title="Accept">Section&nbsp;10.1</a>) header fields in order to provide open and extensible data typing and type negotiation.
    2254       </p>
    2255       <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> )
     2193      <p id="rfc.section.6.5.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.1"><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.2" 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.2" title="Accept">Section&nbsp;10.1</a>) header fields in order to provide open and extensible data typing and type negotiation.
     2194      </p>
     2195      <div id="rfc.figure.u.16"></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> )
    22562196  <a href="#media.types" class="smpl">type</a>       = <a href="#imported.abnf" class="smpl">token</a>
    22572197  <a href="#media.types" class="smpl">subtype</a>    = <a href="#imported.abnf" class="smpl">token</a>
    … …  
    22602200         </p>
    22612201      </div>
    2262       <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>
     2202      <div id="rfc.figure.u.17"></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>
    22632203  <a href="#rule.parameter" class="smpl">attribute</a>      = <a href="#imported.abnf" class="smpl">token</a>
    22642204  <a href="#rule.parameter" class="smpl">value</a>          = <a href="#imported.abnf" class="smpl">word</a>
    … …  
    23102250         of subtags:
    23112251      </p>
    2312       <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;
     2252      <div id="rfc.figure.u.18"></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;
    23132253</pre><p id="rfc.section.6.6.p.4">White space is not allowed within the tag and all tags are case-insensitive. The name space of language subtags is administered
    23142254         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;).
    23152255      </p>
    2316       <div id="rfc.figure.u.20"></div>
     2256      <div id="rfc.figure.u.19"></div>
    23172257      <p>Example tags include:</p>  <pre class="text">  en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN
    23182258</pre> <p id="rfc.section.6.6.p.6">See <a href="#RFC5646" id="rfc.xref.RFC5646.3"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a> for further information.
    … …  
    23432283               <tr>
    23442284                  <td class="left">Content-Length</td>
    2345                   <td class="left"><a href="p1-messaging.html#header.content-length" title="Content-Length">Section 3.3.2</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></td>
     2285                  <td class="left"><a href="p1-messaging.html#header.content-length" title="Content-Length">Section 3.3.2</a> of <a href="#Part1" id="rfc.xref.Part1.24"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a></td>
    23462286               </tr>
    23472287               <tr>
    … …  
    23532293      </div>
    23542294      <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a>&nbsp;<a id="payload.body" href="#payload.body">Payload Body</a></h2>
    2355       <p id="rfc.section.7.2.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.Part1.30"><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.
     2295      <p id="rfc.section.7.2.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.Part1.25"><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.
    23562296      </p>
    23572297      <div id="rfc.iref.r.1"></div>
    … …  
    23722312         in an HTTP message, it is referred to as the payload of the message.
    23732313      </p>
    2374       <p id="rfc.section.8.p.4">A representation 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.Part1.31"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>. The representation 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.
     2314      <p id="rfc.section.8.p.4">A representation 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 representation 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.
    23752315      </p>
    23762316      <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a>&nbsp;<a id="identifying.response.associated.with.representation" href="#identifying.response.associated.with.representation">Identifying the Resource Associated with a Representation</a></h2>
    23772317      <p id="rfc.section.8.1.p.1">It is sometimes necessary to determine an identifier for the resource associated with a representation.</p>
    23782318      <p id="rfc.section.8.1.p.2">An HTTP request representation, when present, is always associated with an anonymous (i.e., unidentified) resource.</p>
    2379       <p id="rfc.section.8.1.p.3">In the common case, an HTTP response is a representation of the target resource (see <a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</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>). However, this is not always the case. To determine the URI of the resource a response is associated with, the following
     2319      <p id="rfc.section.8.1.p.3">In the common case, an HTTP response is a representation of the target resource (see <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>). However, this is not always the case. To determine the URI of the resource a response is associated with, the following
    23802320         rules are used (with the first applicable one being selected):
    23812321      </p>
    … …  
    24262366               <tr>
    24272367                  <td class="left">Content-Type</td>
    2428                   <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.4" title="Content-Type">Section&nbsp;10.9</a></td>
     2368                  <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.3" title="Content-Type">Section&nbsp;10.9</a></td>
    24292369               </tr>
    24302370               <tr>
    24312371                  <td class="left">Expires</td>
    2432                   <td class="left"><a href="p6-cache.html#header.expires" title="Expires">Section 7.3</a> of <a href="#Part6" id="rfc.xref.Part6.17"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
     2372                  <td class="left"><a href="p6-cache.html#header.expires" title="Expires">Section 7.3</a> of <a href="#Part6" id="rfc.xref.Part6.16"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
    24332373               </tr>
    24342374            </tbody>
    … …  
    24692409      <p id="rfc.section.8.3.p.2">The data type of the representation data is determined via the header fields <a href="#header.content-type" class="smpl">Content-Type</a> and <a href="#header.content-encoding" class="smpl">Content-Encoding</a>. These define a two-layer, ordered encoding model:
    24702410      </p>
    2471       <div id="rfc.figure.u.21"></div><pre class="text">  representation-data := Content-Encoding( Content-Type( bits ) )
     2411      <div id="rfc.figure.u.20"></div><pre class="text">  representation-data := Content-Encoding( Content-Type( bits ) )
    24722412</pre><p id="rfc.section.8.3.p.4"> <a href="#header.content-type" class="smpl">Content-Type</a> specifies the media type of the underlying data, which defines both the data format and how that data <em class="bcp14">SHOULD</em> be processed by the recipient (within the scope of the request method semantics). Any HTTP/1.1 message containing a payload
    24732413         body <em class="bcp14">SHOULD</em> include a Content-Type header field defining the media type of the associated representation unless that metadata is unknown
    … …  
    25462486         </p>
    25472487      </div>
    2548       <p id="rfc.section.9.1.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.Part6.18"><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.
     2488      <p id="rfc.section.9.1.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.
    25492489      </p>
    25502490      <h2 id="rfc.section.9.2"><a href="#rfc.section.9.2">9.2</a>&nbsp;<a id="agent-driven.negotiation" href="#agent-driven.negotiation">Agent-driven Negotiation</a></h2>
    … …  
    25762516         a value of 0 means "not acceptable". If no "q" parameter is present, the default weight is 1.
    25772517      </p>
    2578       <div id="rfc.figure.u.22"></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>
     2518      <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>
    25792519  <a href="#quality.values" class="smpl">qvalue</a> = ( "0" [ "." 0*3<a href="#imported.abnf" class="smpl">DIGIT</a> ] )
    25802520         / ( "1" [ "." 0*3("0") ] )
    … …  
    25932533         for an in-line image.
    25942534      </p>
    2595       <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.33"></span><span id="rfc.iref.g.34"></span><span id="rfc.iref.g.35"></span><span id="rfc.iref.g.36"></span>  <a href="#header.accept" class="smpl">Accept</a> = #( <a href="#header.accept" class="smpl">media-range</a> [ <a href="#header.accept" class="smpl">accept-params</a> ] )
     2535      <div id="rfc.figure.u.22"></div><pre class="inline"><span id="rfc.iref.g.33"></span><span id="rfc.iref.g.34"></span><span id="rfc.iref.g.35"></span><span id="rfc.iref.g.36"></span>  <a href="#header.accept" class="smpl">Accept</a> = #( <a href="#header.accept" class="smpl">media-range</a> [ <a href="#header.accept" class="smpl">accept-params</a> ] )
    25962536 
    25972537  <a href="#header.accept" class="smpl">media-range</a>    = ( "*/*"
    … …  
    26142554      </div>
    26152555      <p id="rfc.section.10.1.p.6">The example</p>
    2616       <div id="rfc.figure.u.24"></div><pre class="text">  Accept: audio/*; q=0.2, audio/basic
     2556      <div id="rfc.figure.u.23"></div><pre class="text">  Accept: audio/*; q=0.2, audio/basic
    26172557</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
    26182558         quality".
    … …  
    26232563      </p>
    26242564      <p id="rfc.section.10.1.p.10">A more elaborate example is</p>
    2625       <div id="rfc.figure.u.25"></div><pre class="text">  Accept: text/plain; q=0.5, text/html,
     2565      <div id="rfc.figure.u.24"></div><pre class="text">  Accept: text/plain; q=0.5, text/html,
    26262566          text/x-dvi; q=0.8, text/x-c
    26272567</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
    … …  
    26312571         to a given type, the most specific reference has precedence. For example,
    26322572      </p>
    2633       <div id="rfc.figure.u.26"></div><pre class="text">  Accept: text/*, text/plain, text/plain;format=flowed, */*
     2573      <div id="rfc.figure.u.25"></div><pre class="text">  Accept: text/*, text/plain, text/plain;format=flowed, */*
    26342574</pre><p id="rfc.section.10.1.p.15">have the following precedence: </p>
    26352575      <ol>
    … …  
    26422582         which matches that type. For example,
    26432583      </p>
    2644       <div id="rfc.figure.u.27"></div><pre class="text">  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
     2584      <div id="rfc.figure.u.26"></div><pre class="text">  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
    26452585          text/html;level=2;q=0.4, */*;q=0.5
    26462586</pre><p id="rfc.section.10.1.p.18">would cause the following values to be associated:</p>
    … …  
    26912631         that capability to a server which is capable of representing documents in those character encodings.
    26922632      </p>
    2693       <div id="rfc.figure.u.28"></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> ] )
     2633      <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> ] )
    26942634</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;6.3</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;9.3</a>. An example is
    26952635      </p>
    2696       <div id="rfc.figure.u.29"></div><pre class="text">  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
     2636      <div id="rfc.figure.u.28"></div><pre class="text">  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
    26972637</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
    26982638         in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then any character encodings not explicitly
    … …  
    27092649         no encoding is preferred.
    27102650      </p>
    2711       <div id="rfc.figure.u.30"></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> ] )
     2651      <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> ] )
    27122652  <a href="#header.accept-encoding" class="smpl">codings</a>          = <a href="#content.codings" class="smpl">content-coding</a> / "identity" / "*"
    27132653</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;9.3</a>.
    27142654      </p>
    27152655      <p id="rfc.section.10.3.p.4">For example,</p>
    2716       <div id="rfc.figure.u.31"></div><pre class="text">  Accept-Encoding: compress, gzip
     2656      <div id="rfc.figure.u.30"></div><pre class="text">  Accept-Encoding: compress, gzip
    27172657  Accept-Encoding:
    27182658  Accept-Encoding: *
    … …  
    27502690         in the response. Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;6.6</a>.
    27512691      </p>
    2752       <div id="rfc.figure.u.32"></div><pre class="inline"><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span>  <a href="#header.accept-language" class="smpl">Accept-Language</a> = 1#( <a href="#header.accept-language" class="smpl">language-range</a> [ <a href="#quality.values" class="smpl">weight</a> ] )
     2692      <div id="rfc.figure.u.31"></div><pre class="inline"><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span>  <a href="#header.accept-language" class="smpl">Accept-Language</a> = 1#( <a href="#header.accept-language" class="smpl">language-range</a> [ <a href="#quality.values" class="smpl">weight</a> ] )
    27532693  <a href="#header.accept-language" class="smpl">language-range</a>  =
    27542694            &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;
    … …  
    27562696         languages specified by that range, as defined in <a href="#quality.values" title="Quality Values">Section&nbsp;9.3</a>. For example,
    27572697      </p>
    2758       <div id="rfc.figure.u.33"></div><pre class="text">  Accept-Language: da, en-gb;q=0.8, en;q=0.7
     2698      <div id="rfc.figure.u.32"></div><pre class="text">  Accept-Language: da, en-gb;q=0.8, en;q=0.7
    27592699</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>)
    27602700      </p>
    … …  
    27842724         is strictly to inform the recipient of valid request methods associated with the resource.
    27852725      </p>
    2786       <div id="rfc.figure.u.34"></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>
     2726      <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>
    27872727</pre><p id="rfc.section.10.5.p.3">Example of use:</p>
    2788       <div id="rfc.figure.u.35"></div><pre class="text">  Allow: GET, HEAD, PUT
     2728      <div id="rfc.figure.u.34"></div><pre class="text">  Allow: GET, HEAD, PUT
    27892729</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>
    27902730      <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
    … …  
    27982738         its underlying media type.
    27992739      </p>
    2800       <div id="rfc.figure.u.36"></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>
     2740      <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>
    28012741</pre><p id="rfc.section.10.6.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Section&nbsp;6.4</a>. An example of its use is
    28022742      </p>
    2803       <div id="rfc.figure.u.37"></div><pre class="text">  Content-Encoding: gzip
     2743      <div id="rfc.figure.u.36"></div><pre class="text">  Content-Encoding: gzip
    28042744</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
    28052745         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
    … …  
    28252765         that this might not be equivalent to all the languages used within the representation.
    28262766      </p>
    2827       <div id="rfc.figure.u.38"></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>
     2767      <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>
    28282768</pre><p id="rfc.section.10.7.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;6.6</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate representations according to the
    28292769         user's own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate
    28302770         field is
    28312771      </p>
    2832       <div id="rfc.figure.u.39"></div><pre class="text">  Content-Language: da
     2772      <div id="rfc.figure.u.38"></div><pre class="text">  Content-Language: da
    28332773</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
    28342774         that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language
    … …  
    28382778         simultaneously in the original Maori and English versions, would call for
    28392779      </p>
    2840       <div id="rfc.figure.u.40"></div><pre class="text">  Content-Language: mi, en
     2780      <div id="rfc.figure.u.39"></div><pre class="text">  Content-Language: mi, en
    28412781</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
    28422782         linguistic audiences. An example would be a beginner's language primer, such as "A First Lesson in Latin", which is clearly
    … …  
    28512791         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.
    28522792      </p>
    2853       <div id="rfc.figure.u.41"></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>
    2854 </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.Part1.33"><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
     2793      <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>
     2794</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.Part1.28"><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
    28552795         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.
    28562796      </p>
    … …  
    28912831         the media type is that which would have been sent had the request been a GET.
    28922832      </p>
    2893       <div id="rfc.figure.u.42"></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>
     2833      <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>
    28942834</pre><p id="rfc.section.10.9.p.3">Media types are defined in <a href="#media.types" title="Media Types">Section&nbsp;6.5</a>. An example of the field is
    28952835      </p>
    2896       <div id="rfc.figure.u.43"></div><pre class="text">  Content-Type: text/html; charset=ISO-8859-4
     2836      <div id="rfc.figure.u.42"></div><pre class="text">  Content-Type: text/html; charset=ISO-8859-4
    28972837</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;8.3</a>.
    28982838      </p>
    … …  
    29032843         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;6.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.
    29042844      </p>
    2905       <div id="rfc.figure.u.44"></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>
     2845      <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>
    29062846</pre><p id="rfc.section.10.10.p.3">An example is</p>
    2907       <div id="rfc.figure.u.45"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
     2847      <div id="rfc.figure.u.44"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
    29082848</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:
    29092849      </p>
    … …  
    29312871      <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>
    29322872      <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>
    2933       <div id="rfc.figure.u.46"></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>
     2873      <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>
    29342874 
    29352875  <a href="#header.expect" class="smpl">expectation</a>  = <a href="#header.expect" class="smpl">expect-name</a> [ <a href="#imported.abnf" class="smpl">BWS</a> "=" <a href="#imported.abnf" class="smpl">BWS</a> <a href="#header.expect" class="smpl">expect-value</a> ]
    … …  
    29462886      </p>
    29472887      <ul class="empty">
    2948          <li>The "100-continue" expectation is defined <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.Part1.34"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>. It does not support any expect-params.
     2888         <li>The "100-continue" expectation is defined <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.Part1.29"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>. It does not support any expect-params.
    29492889         </li>
    29502890      </ul>
    … …  
    29592899      <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>:
    29602900      </p>
    2961       <div id="rfc.figure.u.47"></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>
     2901      <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>
    29622902 
    29632903  <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;
    29642904</pre><p id="rfc.section.10.12.p.3">An example is:</p>
    2965       <div id="rfc.figure.u.48"></div><pre class="text">  From: webmaster@example.org
     2905      <div id="rfc.figure.u.47"></div><pre class="text">  From: webmaster@example.org
    29662906</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
    29672907         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
    … …  
    29802920      <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.
    29812921      </p>
    2982       <div id="rfc.figure.u.49"></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>
     2922      <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>
    29832923</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.
    29842924      </p>
    … …  
    29862926         then the original URI's fragment identifier is added to the final value.
    29872927      </p>
    2988       <div id="rfc.figure.u.50"></div>
     2928      <div id="rfc.figure.u.49"></div>
    29892929      <p>For example, the original URI "http://www.example.org/~tim", combined with a field value given as:</p>  <pre class="text">  Location: /pub/WWW/People.html#tim
    29902930</pre>  <p>would result in a final value of "http://www.example.org/pub/WWW/People.html#tim"</p>
    2991       <div id="rfc.figure.u.51"></div>
     2931      <div id="rfc.figure.u.50"></div>
    29922932      <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
    29932933</pre>  <p>would result in a final value of "http://www.example.net/index.html#larry", preserving the original fragment identifier.</p>
    … …  
    30122952         to trace a request which appears to be failing or looping mid-chain.
    30132953      </p>
    3014       <div id="rfc.figure.u.52"></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>
     2954      <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>
    30152955</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>
    30162956      <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).
    … …  
    30322972         non-HTTP URIs (e.g., FTP).
    30332973      </p>
    3034       <div id="rfc.figure.u.53"></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>
     2974      <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>
    30352975</pre><p id="rfc.section.10.15.p.5">Example:</p>
    3036       <div id="rfc.figure.u.54"></div><pre class="text">  Referer: http://www.example.org/hypertext/Overview.html
     2976      <div id="rfc.figure.u.53"></div><pre class="text">  Referer: http://www.example.org/hypertext/Overview.html
    30372977</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.
    30382978      </p>
    … …  
    30442984      </p>
    30452985      <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>
    3046       <div id="rfc.figure.u.55"></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>
     2986      <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>
    30472987</pre><div id="rule.delta-seconds">
    30482988         <p id="rfc.section.10.16.p.4">  Time spans are non-negative decimal integers, representing time in seconds.</p>
    30492989      </div>
    3050       <div id="rfc.figure.u.56"></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>
     2990      <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>
    30512991</pre><p id="rfc.section.10.16.p.6">Two examples of its use are</p>
    3052       <div id="rfc.figure.u.57"></div><pre class="text">  Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
     2992      <div id="rfc.figure.u.56"></div><pre class="text">  Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
    30532993  Retry-After: 120
    30542994</pre><p id="rfc.section.10.16.p.8">In the latter example, the delay is 2 minutes.</p>
    … …  
    30572997      <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>
    30582998      <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>
    3059       <p id="rfc.section.10.17.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.35"><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
     2999      <p id="rfc.section.10.17.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.30"><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
    30603000         identifying the application.
    30613001      </p>
    3062       <div id="rfc.figure.u.58"></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> ) )
     3002      <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> ) )
    30633003</pre><p id="rfc.section.10.17.p.4">Example:</p>
    3064       <div id="rfc.figure.u.59"></div><pre class="text">  Server: CERN/3.0 libwww/2.17
    3065 </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.Part1.36"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
     3004      <div id="rfc.figure.u.58"></div><pre class="text">  Server: CERN/3.0 libwww/2.17
     3005</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.Part1.31"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
    30663006      </p>
    30673007      <div class="note" id="rfc.section.10.17.p.7">
    … …  
    30793019         user agent limitations.
    30803020      </p>
    3081       <p id="rfc.section.10.18.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.37"><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
     3021      <p id="rfc.section.10.18.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.32"><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
    30823022         for identifying the application.
    30833023      </p>
    … …  
    30903030         doing so makes the field value more difficult to parse.
    30913031      </p>
    3092       <div id="rfc.figure.u.60"></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> ) )
     3032      <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> ) )
    30933033</pre><p id="rfc.section.10.18.p.7">Example:</p>
    3094       <div id="rfc.figure.u.61"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
     3034      <div id="rfc.figure.u.60"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    30953035</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>
    30963036      <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>
    … …  
    31163056         specific to a single application or data format, since orthogonal technologies deserve orthogonal specification.
    31173057      </p>
    3118       <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.Part1.38"><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
     3058      <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.Part1.33"><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
    31193059         algorithm or prohibit the presence of a message body on either the request or the response message. Definitions of new methods
    31203060         can specify that only zero-length bodies are allowed, which would imply that each such messages would be required to contain
    … …  
    32213161         a zero-length response body. They can require the presence of one or more particular HTTP response header field(s).
    32223162      </p>
    3223       <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.Part6.19"><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;8.1</a>; by default, it is anonymous).
     3163      <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;8.1</a>; by default, it is anonymous).
    32243164      </p>
    32253165      <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>
    … …  
    34553395         </table>
    34563396      </div>
    3457       <h2 id="rfc.section.11.3"><a href="#rfc.section.11.3">11.3</a>&nbsp;<a id="header.field.registration" href="#header.field.registration">Header Field Registration</a></h2>
    3458       <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; (see <a href="#RFC3864" id="rfc.xref.RFC3864.3"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>). The Message Header Field Registry shall be updated with the permanent registrations below:
    3459       </p>
     3397      <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>
     3398      <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>.
     3399      </p>
     3400      <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>
     3401      <p id="rfc.section.11.3.1.p.1">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
     3402         with "X-" if they are to be registered (either immediately or in the future).
     3403      </p>
     3404      <p id="rfc.section.11.3.1.p.2">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
     3405         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>.
     3406      </p>
     3407      <p id="rfc.section.11.3.1.p.3">Because commas (",") are used as a generic delimiter between field-values, they need to be treated with care if they are allowed
     3408         in the field-value's payload. Typically, components that might contain a comma are protected with double-quotes using the
     3409         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>).
     3410      </p>
     3411      <p id="rfc.section.11.3.1.p.4">For example, a textual date and a URI (either of which might contain a comma) could be safely carried in field-values like
     3412         these:
     3413      </p>
     3414      <div id="rfc.figure.u.61"></div><pre class="text">  Example-URI-Field: "http://example.com/a.html,foo",
     3415                     "http://without-a-comma.example.com/"
     3416  Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005"
     3417</pre><p id="rfc.section.11.3.1.p.6">Note that double-quote delimiters almost always are used with the quoted-string production; using a different syntax inside
     3418         double-quotes will likely cause unnecessary confusion.
     3419      </p>
     3420      <p id="rfc.section.11.3.1.p.7">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
     3421         parser components. When allowing both forms, the meaning of a parameter value ought to be independent of the syntax used for
     3422         it (for an example, see the notes on parameter handling for media types in <a href="#media.types" title="Media Types">Section&nbsp;6.5</a>).
     3423      </p>
     3424      <p id="rfc.section.11.3.1.p.8">Authors of specifications defining new header fields are advised to consider documenting: </p>
     3425      <ul>
     3426         <li>
     3427            <p>Whether the field is a single value, or whether it can be a list (delimited by commas; see <a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.36"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
     3428            </p>
     3429            <p>If it does not use the list syntax, document how to treat messages where the header field occurs multiple times (a sensible
     3430               default would be to ignore the header field, but this might not always be the right choice).
     3431            </p>
     3432            <p>Note that intermediaries and software libraries might combine multiple header field instances into a single one, despite the
     3433               header field not allowing this. A robust format enables recipients to discover these situations (good example: "Content-Type",
     3434               as the comma can only appear inside quoted strings; bad example: "Location", as a comma can occur inside a URI).
     3435            </p>
     3436         </li>
     3437         <li>
     3438            <p>Under what conditions the header field can be used; e.g., only in responses or requests, in all messages, only on responses
     3439               to a particular request method.
     3440            </p>
     3441         </li>
     3442         <li>
     3443            <p>Whether it is appropriate to list the field-name in the <a href="p1-messaging.html#header.connection" class="smpl">Connection</a> header field (i.e., if the header field is to be hop-by-hop, see <a href="p1-messaging.html#header.connection" title="Connection">Section 6.1</a> of <a href="#Part1" id="rfc.xref.Part1.37"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
     3444            </p>
     3445         </li>
     3446         <li>
     3447            <p>Under what conditions intermediaries are allowed to modify the header field's value, insert or delete it.</p>
     3448         </li>
     3449         <li>
     3450            <p>How the header field might interact with caching (see <a href="#Part6" id="rfc.xref.Part6.19"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     3451            </p>
     3452         </li>
     3453         <li>
     3454            <p>Whether the header field is useful or allowable in trailers (see <a href="p1-messaging.html#chunked.encoding" title="Chunked Transfer Coding">Section 4.1</a> of <a href="#Part1" id="rfc.xref.Part1.38"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>).
     3455            </p>
     3456         </li>
     3457         <li>
     3458            <p>Whether the header field ought to be preserved across redirects.</p>
     3459         </li>
     3460      </ul>
     3461      <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>
     3462      <p id="rfc.section.11.3.2.p.1">The Message Header Field Registry shall be updated with the following permanent registrations:</p>
    34603463      <div id="rfc.table.4">
    34613464         <div id="iana.header.registration.table"></div>
    … …  
    36063609         </table>
    36073610      </div>
    3608       <p id="rfc.section.11.3.p.2">The change controller for the above registrations is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
     3611      <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>
    36093612      <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>
    36103613      <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;.
    … …  
    48594862            </li>
    48604863            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
    4861                   <li>Accept header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">4.6</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.a.1"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3</a></li>
    4862                   <li>Accept-Charset header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">4.6</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</a>, <a href="#rfc.iref.a.2"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>
    4863                   <li>Accept-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">4.6</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</a>, <a href="#rfc.iref.a.3"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li>
    4864                   <li>Accept-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">4.6</a>, <a href="#rfc.xref.header.accept-language.2">9.1</a>, <a href="#rfc.iref.a.4"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3</a></li>
    4865                   <li>Allow header field&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4.7</a>, <a href="#rfc.iref.a.5"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3</a>, <a href="#rfc.xref.header.allow.4">C</a></li>
     4864                  <li>Accept header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">4.5</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.a.1"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3.2</a></li>
     4865                  <li>Accept-Charset header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">4.5</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</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>
     4866                  <li>Accept-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">4.5</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</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>
     4867                  <li>Accept-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">4.5</a>, <a href="#rfc.xref.header.accept-language.2">9.1</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>
     4868                  <li>Allow header field&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4.6</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>
    48664869               </ul>
    48674870            </li>
    … …  
    48784881                  <li>CONNECT method&nbsp;&nbsp;<a href="#rfc.xref.CONNECT.1">3.1</a>, <a href="#rfc.iref.c.3"><b>3.3.8</b></a>, <a href="#rfc.xref.CONNECT.2">11.1.3</a>, <a href="#rfc.xref.CONNECT.3">C</a></li>
    48794882                  <li>content negotiation&nbsp;&nbsp;<a href="#rfc.iref.c.1">1</a></li>
    4880                   <li>Content-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</a>, <a href="#rfc.iref.c.8"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3</a></li>
    4881                   <li>Content-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">8.2</a>, <a href="#rfc.iref.c.9"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3</a></li>
    4882                   <li>Content-Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</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</a>, <a href="#rfc.xref.header.content-location.5">C</a></li>
     4883                  <li>Content-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</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>
     4884                  <li>Content-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">8.2</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>
     4885                  <li>Content-Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</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>
    48834886                  <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>
    4884                   <li>Content-Type header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">4.5</a>, <a href="#rfc.xref.header.content-type.2">5</a>, <a href="#rfc.xref.header.content-type.3">6.5</a>, <a href="#rfc.xref.header.content-type.4">8.2</a>, <a href="#rfc.iref.c.11"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.5">11.3</a></li>
     4887                  <li>Content-Type header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">5</a>, <a href="#rfc.xref.header.content-type.2">6.5</a>, <a href="#rfc.xref.header.content-type.3">8.2</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>
    48854888               </ul>
    48864889            </li>
    48874890            <li><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul>
    4888                   <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">4.7</a>, <a href="#rfc.iref.d.3"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3</a></li>
     4891                  <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">4.6</a>, <a href="#rfc.iref.d.3"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3.2</a></li>
    48894892                  <li>deflate (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.d.2">6.4</a></li>
    48904893                  <li>DELETE method&nbsp;&nbsp;<a href="#rfc.xref.DELETE.1">3.1</a>, <a href="#rfc.iref.d.1"><b>3.3.6</b></a>, <a href="#rfc.xref.DELETE.2">11.1.3</a></li>
    … …  
    48924895            </li>
    48934896            <li><a id="rfc.index.E" href="#rfc.index.E"><b>E</b></a><ul>
    4894                   <li>Expect header field&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">4.6</a>, <a href="#rfc.xref.header.expect.2">5.5.14</a>, <a href="#rfc.iref.e.1"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3</a>, <a href="#rfc.xref.header.expect.4">C</a></li>
     4897                  <li>Expect header field&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">4.5</a>, <a href="#rfc.xref.header.expect.2">5.5.14</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>
    48954898                  <li>Expect Values&nbsp;&nbsp;
    48964899                     <ul>
    … …  
    49014904            </li>
    49024905            <li><a id="rfc.index.F" href="#rfc.index.F"><b>F</b></a><ul>
    4903                   <li>From header field&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">4.6</a>, <a href="#rfc.iref.f.1"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3</a></li>
     4906                  <li>From header field&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">4.5</a>, <a href="#rfc.iref.f.1"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3.2</a></li>
    49044907               </ul>
    49054908            </li>
    … …  
    49764979                  <li>Header Fields&nbsp;&nbsp;
    49774980                     <ul>
    4978                         <li>Accept&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">4.6</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.h.2"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3</a></li>
    4979                         <li>Accept-Charset&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">4.6</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</a>, <a href="#rfc.iref.h.3"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>
    4980                         <li>Accept-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">4.6</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</a>, <a href="#rfc.iref.h.4"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li>
    4981                         <li>Accept-Language&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">4.6</a>, <a href="#rfc.xref.header.accept-language.2">9.1</a>, <a href="#rfc.iref.h.5"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3</a></li>
    4982                         <li>Allow&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4.7</a>, <a href="#rfc.iref.h.6"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3</a>, <a href="#rfc.xref.header.allow.4">C</a></li>
    4983                         <li>Content-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</a>, <a href="#rfc.iref.h.7"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3</a></li>
    4984                         <li>Content-Language&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">8.2</a>, <a href="#rfc.iref.h.8"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3</a></li>
    4985                         <li>Content-Location&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</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</a>, <a href="#rfc.xref.header.content-location.5">C</a></li>
     4981                        <li>Accept&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">4.5</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.h.2"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3.2</a></li>
     4982                        <li>Accept-Charset&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">4.5</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</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>
     4983                        <li>Accept-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">4.5</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</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>
     4984                        <li>Accept-Language&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">4.5</a>, <a href="#rfc.xref.header.accept-language.2">9.1</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>
     4985                        <li>Allow&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4.6</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>
     4986                        <li>Content-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</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>
     4987                        <li>Content-Language&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">8.2</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>
     4988                        <li>Content-Location&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</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>
    49864989                        <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>
    4987                         <li>Content-Type&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">4.5</a>, <a href="#rfc.xref.header.content-type.2">5</a>, <a href="#rfc.xref.header.content-type.3">6.5</a>, <a href="#rfc.xref.header.content-type.4">8.2</a>, <a href="#rfc.iref.h.10"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.5">11.3</a></li>
    4988                         <li>Date&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">4.7</a>, <a href="#rfc.iref.h.11"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3</a></li>
    4989                         <li>Expect&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">4.6</a>, <a href="#rfc.xref.header.expect.2">5.5.14</a>, <a href="#rfc.iref.h.12"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3</a>, <a href="#rfc.xref.header.expect.4">C</a></li>
    4990                         <li>From&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">4.6</a>, <a href="#rfc.iref.h.13"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3</a></li>
    4991                         <li>Location&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4.7</a>, <a href="#rfc.xref.header.location.3">5.4</a>, <a href="#rfc.iref.h.14"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3</a>, <a href="#rfc.xref.header.location.5">C</a></li>
    4992                         <li>Max-Forwards&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4.6</a>, <a href="#rfc.iref.h.15"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>
    4993                         <li>MIME-Version&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">11.3</a>, <a href="#rfc.iref.h.20"><b>A.1</b></a></li>
    4994                         <li>Referer&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">4.6</a>, <a href="#rfc.iref.h.16"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3</a>, <a href="#rfc.xref.header.referer.3">C</a></li>
    4995                         <li>Retry-After&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">4.7</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</a>, <a href="#rfc.iref.h.17"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3</a></li>
    4996                         <li>Server&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">4.7</a>, <a href="#rfc.iref.h.18"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>
    4997                         <li>User-Agent&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">4.6</a>, <a href="#rfc.xref.header.user-agent.2">9.1</a>, <a href="#rfc.iref.h.19"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li>
     4990                        <li>Content-Type&nbsp;&nbsp;<a href="#rfc.xref.header.content-type.1">5</a>, <a href="#rfc.xref.header.content-type.2">6.5</a>, <a href="#rfc.xref.header.content-type.3">8.2</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>
     4991                        <li>Date&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">4.6</a>, <a href="#rfc.iref.h.11"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3.2</a></li>
     4992                        <li>Expect&nbsp;&nbsp;<a href="#rfc.xref.header.expect.1">4.5</a>, <a href="#rfc.xref.header.expect.2">5.5.14</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>
     4993                        <li>From&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">4.5</a>, <a href="#rfc.iref.h.13"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3.2</a></li>
     4994                        <li>Location&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4.6</a>, <a href="#rfc.xref.header.location.3">5.4</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>
     4995                        <li>Max-Forwards&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4.5</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>
     4996                        <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>
     4997                        <li>Referer&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">4.5</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>
     4998                        <li>Retry-After&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">4.6</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</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>
     4999                        <li>Server&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">4.6</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>
     5000                        <li>User-Agent&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">4.5</a>, <a href="#rfc.xref.header.user-agent.2">9.1</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>
    49985001                     </ul>
    49995002                  </li>
    … …  
    50055008            </li>
    50065009            <li><a id="rfc.index.L" href="#rfc.index.L"><b>L</b></a><ul>
    5007                   <li>Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4.7</a>, <a href="#rfc.xref.header.location.3">5.4</a>, <a href="#rfc.iref.l.1"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3</a>, <a href="#rfc.xref.header.location.5">C</a></li>
     5010                  <li>Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4.6</a>, <a href="#rfc.xref.header.location.3">5.4</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>
    50085011               </ul>
    50095012            </li>
    50105013            <li><a id="rfc.index.M" href="#rfc.index.M"><b>M</b></a><ul>
    5011                   <li>Max-Forwards header field&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4.6</a>, <a href="#rfc.iref.m.9"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>
     5014                  <li>Max-Forwards header field&nbsp;&nbsp;<a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4.5</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>
    50125015                  <li>Methods&nbsp;&nbsp;
    50135016                     <ul>
    … …  
    50225025                     </ul>
    50235026                  </li>
    5024                   <li>MIME-Version header field&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">11.3</a>, <a href="#rfc.iref.m.10"><b>A.1</b></a></li>
     5027                  <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>
    50255028               </ul>
    50265029            </li>
    … …  
    50305033            </li>
    50315034            <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul>
    5032                   <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">3.3.1</a>, <a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.9">3.3.7</a>, <a href="#rfc.xref.Part1.10">3.3.8</a>, <a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1.12">4.5</a>, <a href="#rfc.xref.Part1.13">4.5</a>, <a href="#rfc.xref.Part1.14">4.5</a>, <a href="#rfc.xref.Part1.15">4.5</a>, <a href="#rfc.xref.Part1.16">4.5</a>, <a href="#rfc.xref.Part1.17">4.6</a>, <a href="#rfc.xref.Part1.18">4.6</a>, <a href="#rfc.xref.Part1.19">4.7</a>, <a href="#rfc.xref.Part1.20">5.2.1</a>, <a href="#rfc.xref.Part1.21">5.2.2</a>, <a href="#rfc.xref.Part1.22">5.3.4</a>, <a href="#rfc.xref.Part1.23">5.3.6</a>, <a href="#rfc.xref.Part1.24">5.5.15</a>, <a href="#rfc.xref.Part1.25">5.6.6</a>, <a href="#rfc.xref.Part1.26">6.4</a>, <a href="#rfc.xref.Part1.27">6.4</a>, <a href="#rfc.xref.Part1.28">6.4</a>, <a href="#rfc.xref.Part1.29">7.1</a>, <a href="#rfc.xref.Part1.30">7.2</a>, <a href="#rfc.xref.Part1.31">8</a>, <a href="#rfc.xref.Part1.32">8.1</a>, <a href="#rfc.xref.Part1.33">10.8</a>, <a href="#rfc.xref.Part1.34">10.11</a>, <a href="#rfc.xref.Part1.35">10.17</a>, <a href="#rfc.xref.Part1.36">10.17</a>, <a href="#rfc.xref.Part1.37">10.18</a>, <a href="#rfc.xref.Part1.38">11.1.2</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>
     5035                  <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">3.3.1</a>, <a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.9">3.3.7</a>, <a href="#rfc.xref.Part1.10">3.3.8</a>, <a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1.12">4.5</a>, <a href="#rfc.xref.Part1.13">4.5</a>, <a href="#rfc.xref.Part1.14">4.6</a>, <a href="#rfc.xref.Part1.15">5.2.1</a>, <a href="#rfc.xref.Part1.16">5.2.2</a>, <a href="#rfc.xref.Part1.17">5.3.4</a>, <a href="#rfc.xref.Part1.18">5.3.6</a>, <a href="#rfc.xref.Part1.19">5.5.15</a>, <a href="#rfc.xref.Part1.20">5.6.6</a>, <a href="#rfc.xref.Part1.21">6.4</a>, <a href="#rfc.xref.Part1.22">6.4</a>, <a href="#rfc.xref.Part1.23">6.4</a>, <a href="#rfc.xref.Part1.24">7.1</a>, <a href="#rfc.xref.Part1.25">7.2</a>, <a href="#rfc.xref.Part1.26">8</a>, <a href="#rfc.xref.Part1.27">8.1</a>, <a href="#rfc.xref.Part1.28">10.8</a>, <a href="#rfc.xref.Part1.29">10.11</a>, <a href="#rfc.xref.Part1.30">10.17</a>, <a href="#rfc.xref.Part1.31">10.17</a>, <a href="#rfc.xref.Part1.32">10.18</a>, <a href="#rfc.xref.Part1.33">11.1.2</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>
    50335036                        <li><em>Section 1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.3">1.2</a></li>
    5034                         <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.22">5.3.4</a></li>
     5037                        <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.17">5.3.4</a></li>
    50355038                        <li><em>Section 2.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.2">1.1</a></li>
    5036                         <li><em>Section 2.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.25">5.6.6</a></li>
     5039                        <li><em>Section 2.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.20">5.6.6</a></li>
    50375040                        <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>
    5038                         <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1.14">4.5</a>, <a href="#rfc.xref.Part1.35">10.17</a>, <a href="#rfc.xref.Part1.37">10.18</a></li>
     5041                        <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1.30">10.17</a>, <a href="#rfc.xref.Part1.32">10.18</a>, <a href="#rfc.xref.Part1.36">11.3.1</a></li>
    50395042                        <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>
    5040                         <li><em>Section 3.2.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.13">4.5</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>
    5041                         <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.23">5.3.6</a>, <a href="#rfc.xref.Part1.30">7.2</a>, <a href="#rfc.xref.Part1.31">8</a>, <a href="#rfc.xref.Part1.38">11.1.2</a></li>
    5042                         <li><em>Section 3.3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.29">7.1</a></li>
     5043                        <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>
     5044                        <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.18">5.3.6</a>, <a href="#rfc.xref.Part1.25">7.2</a>, <a href="#rfc.xref.Part1.26">8</a>, <a href="#rfc.xref.Part1.33">11.1.2</a></li>
     5045                        <li><em>Section 3.3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.24">7.1</a></li>
    50435046                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.40">11.4.1</a></li>
    5044                         <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.16">4.5</a></li>
    5045                         <li><em>Section 4.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.26">6.4</a>, <a href="#rfc.xref.Part1.42">11.4.2</a></li>
     5047                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.38">11.3.1</a></li>
     5048                        <li><em>Section 4.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.21">6.4</a>, <a href="#rfc.xref.Part1.42">11.4.2</a></li>
    50465049                        <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>
    5047                         <li><em>Section 4.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.27">6.4</a>, <a href="#rfc.xref.Part1.43">11.4.2</a></li>
    5048                         <li><em>Section 4.2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.28">6.4</a>, <a href="#rfc.xref.Part1.44">11.4.2</a></li>
    5049                         <li><em>Section 4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.18">4.6</a></li>
     5050                        <li><em>Section 4.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.22">6.4</a>, <a href="#rfc.xref.Part1.43">11.4.2</a></li>
     5051                        <li><em>Section 4.2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.23">6.4</a>, <a href="#rfc.xref.Part1.44">11.4.2</a></li>
     5052                        <li><em>Section 4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.13">4.5</a></li>
    50505053                        <li><em>Section 5.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.7">3.3.1</a>, <a href="#rfc.xref.Part1.10">3.3.8</a></li>
    5051                         <li><em>Section 5.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.17">4.6</a></li>
    5052                         <li><em>Section 5.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.19">4.7</a>, <a href="#rfc.xref.Part1.32">8.1</a>, <a href="#rfc.xref.Part1.33">10.8</a></li>
    5053                         <li><em>Section 5.7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.36">10.17</a>, <a href="#rfc.xref.Part1.46">C</a></li>
    5054                         <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.15">4.5</a></li>
    5055                         <li><em>Section 6.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.20">5.2.1</a>, <a href="#rfc.xref.Part1.34">10.11</a></li>
    5056                         <li><em>Section 6.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.21">5.2.2</a>, <a href="#rfc.xref.Part1.24">5.5.15</a></li>
     5054                        <li><em>Section 5.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.12">4.5</a></li>
     5055                        <li><em>Section 5.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.14">4.6</a>, <a href="#rfc.xref.Part1.27">8.1</a>, <a href="#rfc.xref.Part1.28">10.8</a></li>
     5056                        <li><em>Section 5.7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.31">10.17</a>, <a href="#rfc.xref.Part1.46">C</a></li>
     5057                        <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.37">11.3.1</a></li>
     5058                        <li><em>Section 6.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.15">5.2.1</a>, <a href="#rfc.xref.Part1.29">10.11</a></li>
     5059                        <li><em>Section 6.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.16">5.2.2</a>, <a href="#rfc.xref.Part1.19">5.5.15</a></li>
    50575060                        <li><em>Section 7.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.9">3.3.7</a></li>
    50585061                        <li><em>Section 9</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.45">13</a></li>
    5059                         <li><em>Appendix B</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.12">4.5</a></li>
     5062                        <li><em>Appendix B</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.34">11.3.1</a></li>
    50605063                     </ul>
    50615064                  </li>
    5062                   <li><em>Part4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">3.3.2</a>, <a href="#rfc.xref.Part4.2">4.6</a>, <a href="#rfc.xref.Part4.3">4.6</a>, <a href="#rfc.xref.Part4.4">4.6</a>, <a href="#rfc.xref.Part4.5">4.6</a>, <a href="#rfc.xref.Part4.6">4.7</a>, <a href="#rfc.xref.Part4.7">5.1</a>, <a href="#rfc.xref.Part4.8">5.1</a>, <a href="#rfc.xref.Part4.9">5.1</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.11">5.4</a>, <a href="#rfc.xref.Part4.12">8.2</a>, <a href="#rfc.xref.Part4.13">8.2</a>, <a href="#Part4"><b>14.1</b></a>, <a href="#rfc.xref.Part4.14">F.2</a><ul>
     5065                  <li><em>Part4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">3.3.2</a>, <a href="#rfc.xref.Part4.2">4.5</a>, <a href="#rfc.xref.Part4.3">4.5</a>, <a href="#rfc.xref.Part4.4">4.5</a>, <a href="#rfc.xref.Part4.5">4.5</a>, <a href="#rfc.xref.Part4.6">4.6</a>, <a href="#rfc.xref.Part4.7">5.1</a>, <a href="#rfc.xref.Part4.8">5.1</a>, <a href="#rfc.xref.Part4.9">5.1</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.11">5.4</a>, <a href="#rfc.xref.Part4.12">8.2</a>, <a href="#rfc.xref.Part4.13">8.2</a>, <a href="#Part4"><b>14.1</b></a>, <a href="#rfc.xref.Part4.14">F.2</a><ul>
    50635066                        <li><em>Section 2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.13">8.2</a></li>
    5064                         <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.6">4.7</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.12">8.2</a></li>
    5065                         <li><em>Section 3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.2">4.6</a></li>
    5066                         <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.4">4.6</a></li>
    5067                         <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.3">4.6</a></li>
    5068                         <li><em>Section 3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.5">4.6</a></li>
     5067                        <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.6">4.6</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.12">8.2</a></li>
     5068                        <li><em>Section 3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.2">4.5</a></li>
     5069                        <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.4">4.5</a></li>
     5070                        <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.3">4.5</a></li>
     5071                        <li><em>Section 3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.5">4.5</a></li>
    50695072                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.7">5.1</a></li>
    50705073                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.8">5.1</a>, <a href="#rfc.xref.Part4.11">5.4</a></li>
    … …  
    50725075                     </ul>
    50735076                  </li>
    5074                   <li><em>Part5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.1">3.3.2</a>, <a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.3">3.3.5</a>, <a href="#rfc.xref.Part5.4">4.6</a>, <a href="#rfc.xref.Part5.5">4.6</a>, <a href="#rfc.xref.Part5.6">4.7</a>, <a href="#rfc.xref.Part5.7">5.1</a>, <a href="#rfc.xref.Part5.8">5.1</a>, <a href="#rfc.xref.Part5.9">5.1</a>, <a href="#rfc.xref.Part5.10">7.1</a>, <a href="#Part5"><b>14.1</b></a><ul>
     5077                  <li><em>Part5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.1">3.3.2</a>, <a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.3">3.3.5</a>, <a href="#rfc.xref.Part5.4">4.5</a>, <a href="#rfc.xref.Part5.5">4.5</a>, <a href="#rfc.xref.Part5.6">4.6</a>, <a href="#rfc.xref.Part5.7">5.1</a>, <a href="#rfc.xref.Part5.8">5.1</a>, <a href="#rfc.xref.Part5.9">5.1</a>, <a href="#rfc.xref.Part5.10">7.1</a>, <a href="#Part5"><b>14.1</b></a><ul>
    50755078                        <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.7">5.1</a></li>
    50765079                        <li><em>Section 3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.8">5.1</a></li>
    50775080                        <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.9">5.1</a></li>
    5078                         <li><em>Section 5.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.6">4.7</a></li>
     5081                        <li><em>Section 5.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.6">4.6</a></li>
    50795082                        <li><em>Section 5.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.3">3.3.5</a>, <a href="#rfc.xref.Part5.10">7.1</a></li>
    5080                         <li><em>Section 5.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.4">4.6</a></li>
    5081                         <li><em>Section 5.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.5">4.6</a></li>
     5083                        <li><em>Section 5.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.4">4.5</a></li>
     5084                        <li><em>Section 5.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.5">4.5</a></li>
    50825085                     </ul>
    50835086                  </li>
    5084                   <li><em>Part6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">3.2.3</a>, <a href="#rfc.xref.Part6.2">3.3.2</a>, <a href="#rfc.xref.Part6.3">3.3.3</a>, <a href="#rfc.xref.Part6.4">3.3.4</a>, <a href="#rfc.xref.Part6.5">3.3.5</a>, <a href="#rfc.xref.Part6.6">3.3.6</a>, <a href="#rfc.xref.Part6.7">4.5</a>, <a href="#rfc.xref.Part6.8">4.7</a>, <a href="#rfc.xref.Part6.9">4.7</a>, <a href="#rfc.xref.Part6.10">5.3.1</a>, <a href="#rfc.xref.Part6.11">5.3.4</a>, <a href="#rfc.xref.Part6.12">5.3.4</a>, <a href="#rfc.xref.Part6.13">5.3.4</a>, <a href="#rfc.xref.Part6.14">5.4.1</a>, <a href="#rfc.xref.Part6.15">5.4.2</a>, <a href="#rfc.xref.Part6.16">5.5.9</a>, <a href="#rfc.xref.Part6.17">8.2</a>, <a href="#rfc.xref.Part6.18">9.1</a>, <a href="#rfc.xref.Part6.19">11.2.2</a>, <a href="#Part6"><b>14.1</b></a><ul>
     5087                  <li><em>Part6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">3.2.3</a>, <a href="#rfc.xref.Part6.2">3.3.2</a>, <a href="#rfc.xref.Part6.3">3.3.3</a>, <a href="#rfc.xref.Part6.4">3.3.4</a>, <a href="#rfc.xref.Part6.5">3.3.5</a>, <a href="#rfc.xref.Part6.6">3.3.6</a>, <a href="#rfc.xref.Part6.7">4.6</a>, <a href="#rfc.xref.Part6.8">4.6</a>, <a href="#rfc.xref.Part6.9">5.3.1</a>, <a href="#rfc.xref.Part6.10">5.3.4</a>, <a href="#rfc.xref.Part6.11">5.3.4</a>, <a href="#rfc.xref.Part6.12">5.3.4</a>, <a href="#rfc.xref.Part6.13">5.4.1</a>, <a href="#rfc.xref.Part6.14">5.4.2</a>, <a href="#rfc.xref.Part6.15">5.5.9</a>, <a href="#rfc.xref.Part6.16">8.2</a>, <a href="#rfc.xref.Part6.17">9.1</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>
    50855088                        <li><em>Section 4.1.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.4">3.3.4</a></li>
    5086                         <li><em>Section 4.1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.10">5.3.1</a>, <a href="#rfc.xref.Part6.13">5.3.4</a>, <a href="#rfc.xref.Part6.14">5.4.1</a>, <a href="#rfc.xref.Part6.15">5.4.2</a>, <a href="#rfc.xref.Part6.16">5.5.9</a></li>
     5089                        <li><em>Section 4.1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.9">5.3.1</a>, <a href="#rfc.xref.Part6.12">5.3.4</a>, <a href="#rfc.xref.Part6.13">5.4.1</a>, <a href="#rfc.xref.Part6.14">5.4.2</a>, <a href="#rfc.xref.Part6.15">5.5.9</a></li>
    50875090                        <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.3">3.3.3</a></li>
    50885091                        <li><em>Section 6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.5">3.3.5</a>, <a href="#rfc.xref.Part6.6">3.3.6</a></li>
    5089                         <li><em>Section 7.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.8">4.7</a></li>
    5090                         <li><em>Section 7.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.11">5.3.4</a></li>
    5091                         <li><em>Section 7.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.17">8.2</a></li>
    5092                         <li><em>Section 7.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.9">4.7</a>, <a href="#rfc.xref.Part6.18">9.1</a></li>
    5093                         <li><em>Section 7.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.12">5.3.4</a></li>
     5092                        <li><em>Section 7.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.7">4.6</a></li>
     5093                        <li><em>Section 7.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.10">5.3.4</a></li>
     5094                        <li><em>Section 7.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.16">8.2</a></li>
     5095                        <li><em>Section 7.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.8">4.6</a>, <a href="#rfc.xref.Part6.17">9.1</a></li>
     5096                        <li><em>Section 7.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.11">5.3.4</a></li>
    50945097                     </ul>
    50955098                  </li>
    5096                   <li><em>Part7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.1">4.6</a>, <a href="#rfc.xref.Part7.2">4.6</a>, <a href="#rfc.xref.Part7.3">4.7</a>, <a href="#rfc.xref.Part7.4">4.7</a>, <a href="#rfc.xref.Part7.5">5.1</a>, <a href="#rfc.xref.Part7.6">5.1</a>, <a href="#rfc.xref.Part7.7">5.1</a>, <a href="#Part7"><b>14.1</b></a><ul>
     5099                  <li><em>Part7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.1">4.5</a>, <a href="#rfc.xref.Part7.2">4.5</a>, <a href="#rfc.xref.Part7.3">4.6</a>, <a href="#rfc.xref.Part7.4">4.6</a>, <a href="#rfc.xref.Part7.5">5.1</a>, <a href="#rfc.xref.Part7.6">5.1</a>, <a href="#rfc.xref.Part7.7">5.1</a>, <a href="#Part7"><b>14.1</b></a><ul>
    50975100                        <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.5">5.1</a></li>
    50985101                        <li><em>Section 3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.6">5.1</a></li>
    50995102                        <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.7">5.1</a></li>
    5100                         <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.1">4.6</a></li>
    5101                         <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.3">4.7</a></li>
    5102                         <li><em>Section 4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.2">4.6</a></li>
    5103                         <li><em>Section 4.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.4">4.7</a></li>
     5103                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.1">4.5</a></li>
     5104                        <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.3">4.6</a></li>
     5105                        <li><em>Section 4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.2">4.5</a></li>
     5106                        <li><em>Section 4.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part7.4">4.6</a></li>
    51045107                     </ul>
    51055108                  </li>
    … …  
    51105113            </li>
    51115114            <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul>
    5112                   <li>Referer header field&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">4.6</a>, <a href="#rfc.iref.r.2"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3</a>, <a href="#rfc.xref.header.referer.3">C</a></li>
     5115                  <li>Referer header field&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">4.5</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>
    51135116                  <li>representation&nbsp;&nbsp;<a href="#rfc.iref.r.1">8</a></li>
    51145117                  <li><em>REST</em>&nbsp;&nbsp;<a href="#rfc.xref.REST.1">3.1</a>, <a href="#REST"><b>14.2</b></a></li>
    5115                   <li>Retry-After header field&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">4.7</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</a>, <a href="#rfc.iref.r.3"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3</a></li>
     5118                  <li>Retry-After header field&nbsp;&nbsp;<a href="#rfc.xref.header.retry-after.1">4.6</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</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>
    51165119                  <li><em>RFC1123</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1123.1">6.1</a>, <a href="#rfc.xref.RFC1123.2">6.1</a>, <a href="#RFC1123"><b>14.2</b></a><ul>
    51175120                        <li><em>Section 5.2.14</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1123.2">6.1</a></li>
    … …  
    51595162                  </li>
    51605163                  <li><em>RFC3629</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3629.1">6.3</a>, <a href="#RFC3629"><b>14.2</b></a></li>
    5161                   <li><em>RFC3864</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.1">4.5</a>, <a href="#rfc.xref.RFC3864.2">4.5</a>, <a href="#rfc.xref.RFC3864.3">11.3</a>, <a href="#RFC3864"><b>14.2</b></a><ul>
    5162                         <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.2">4.5</a></li>
     5164                  <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>
     5165                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.2">11.3.1</a></li>
    51635166                     </ul>
    51645167                  </li>
    … …  
    51805183                     </ul>
    51815184                  </li>
    5182                   <li><em>RFC5234</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.1">1.2</a>, <a href="#rfc.xref.RFC5234.2">4.5</a>, <a href="#RFC5234"><b>14.1</b></a>, <a href="#rfc.xref.RFC5234.3">D</a><ul>
     5185                  <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>
    51835186                        <li><em>Appendix B.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.3">D</a></li>
    51845187                     </ul>
    … …  
    51955198                  </li>
    51965199                  <li><em>RFC5789</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5789.1">3.3.5</a>, <a href="#RFC5789"><b>14.2</b></a></li>
    5197                   <li><em>RFC5987</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5987.1">4.5</a>, <a href="#RFC5987"><b>14.2</b></a></li>
     5200                  <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>
    51985201                  <li><em>RFC6151</em>&nbsp;&nbsp;<a href="#RFC6151"><b>14.2</b></a>, <a href="#rfc.xref.RFC6151.1">C</a></li>
    51995202                  <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>
    … …  
    52035206                  <li>safe&nbsp;&nbsp;<a href="#rfc.iref.s.1"><b>3.2.1</b></a></li>
    52045207                  <li>selected representation&nbsp;&nbsp;<a href="#rfc.iref.s.43"><b>8.2</b></a></li>
    5205                   <li>Server header field&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">4.7</a>, <a href="#rfc.iref.s.44"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>
     5208                  <li>Server header field&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">4.6</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>
    52065209                  <li>Status Codes&nbsp;&nbsp;
    52075210                     <ul>
    … …  
    52615264            </li>
    52625265            <li><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul>
    5263                   <li>User-Agent header field&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">4.6</a>, <a href="#rfc.xref.header.user-agent.2">9.1</a>, <a href="#rfc.iref.u.1"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li>
     5266                  <li>User-Agent header field&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">4.5</a>, <a href="#rfc.xref.header.user-agent.2">9.1</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>
    52645267               </ul>
    52655268            </li>

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

    r1846 r1847  
    976976
    977977<section title="Payload Metadata Fields" anchor="payload.fields">
    978 </section>
    979 
    980 <section title="Considerations for Creating Header Fields" anchor="considerations.for.creating.header.fields">
    981 <t>
    982    New header fields are registered using the procedures described in
    983    <xref target="RFC3864"/>.
    984 </t>
    985 <t>
    986    The requirements for header field names are defined in
    987    <xref target="RFC3864" x:fmt="of" x:sec="4.1"/>.  Authors of specifications
    988    defining new fields are advised to keep the name as short as practical, and
    989    not to prefix them with "X-" if they are to be registered (either
    990    immediately or in the future).
    991 </t>
    992 <t>
    993    New header field values typically have their syntax defined using ABNF
    994    (<xref target="RFC5234"/>), using the extension defined in &abnf-extension;
    995    as necessary, and are usually constrained to the range of ASCII characters.
    996    Header fields needing a greater range of characters can use an encoding
    997    such as the one defined in <xref target="RFC5987"/>.
    998 </t>
    999 <t>
    1000    Because commas (",") are used as a generic delimiter between field-values,
    1001    they need to be treated with care if they are allowed in the field-value's
    1002    payload. Typically, components that might contain a comma are protected with
    1003    double-quotes using the quoted-string ABNF production (&field-components;).
    1004 </t>
    1005 <t>
    1006    For example, a textual date and a URI (either of which might contain a comma)
    1007    could be safely carried in field-values like these:
    1008 </t>
    1009 <figure><artwork type="example">
    1010   Example-URI-Field: "http://example.com/a.html,foo",
    1011                      "http://without-a-comma.example.com/"
    1012   Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005"
    1013 </artwork></figure>
    1014 <t>
    1015    Note that double quote delimiters almost always are used with the
    1016    quoted-string production; using a different syntax inside double quotes
    1017    will likely cause unnecessary confusion.
    1018 </t>
    1019 <t>
    1020    Many header fields use a format including (case-insensitively) named
    1021    parameters (for instance, <x:ref>Content-Type</x:ref>, defined in
    1022    &header-content-type;). Allowing both unquoted (token) and quoted
    1023    (quoted-string) syntax for the parameter value enables recipients to use
    1024    existing parser components. When allowing both forms, the meaning of a
    1025    parameter value ought to be independent of the syntax used for it (for an
    1026    example, see the notes on parameter handling for media types in
    1027    &media-types;).
    1028 </t>
    1029 <t>
    1030    Authors of specifications defining new header fields are advised to consider
    1031    documenting:
    1032   <list style="symbols">
    1033     <x:lt>
    1034       <t>Whether the field is a single value, or whether it can be a list
    1035       (delimited by commas; see &header-fields;).</t>
    1036       <t>If it does not use the list syntax, document how to treat messages
    1037       where the header field occurs multiple times (a sensible default would
    1038       be to ignore the header field, but this might not always be the right
    1039       choice).</t>
    1040       <t>Note that intermediaries and software libraries might combine
    1041       multiple header field instances into a single one, despite the header
    1042       field not allowing this. A robust format enables recipients to discover
    1043       these situations (good example: "Content-Type", as the comma can only
    1044       appear inside quoted strings; bad example: "Location", as a comma can
    1045       occur inside a URI).</t>
    1046     </x:lt>
    1047     <x:lt><t>Under what conditions the header field can be used; e.g., only in
    1048     responses or requests, in all messages, only on responses to a particular
    1049     request method.</t></x:lt>
    1050     <x:lt><t>Whether it is appropriate to list the field-name in the
    1051     <x:ref>Connection</x:ref> header field (i.e., if the header field is to
    1052     be hop-by-hop, see &header-connection;).</t></x:lt>
    1053     <x:lt><t>Under what conditions intermediaries are allowed to modify the header
    1054     field's value, insert or delete it.</t></x:lt>
    1055     <x:lt><t>How the header field might interact with caching (see
    1056     <xref target="Part6"/>).</t></x:lt>
    1057     <x:lt><t>Whether the header field is useful or allowable in trailers (see
    1058     &chunked-encoding;).</t></x:lt>
    1059     <x:lt><t>Whether the header field ought to be preserved across redirects.</t></x:lt>
    1060   </list>
    1061 </t>
    1062978</section>
    1063979
    … …  
    43114227</section>
    43124228
    4313 <section title="Header Field Registration" anchor="header.field.registration">
     4229<section title="Header Field Registry" anchor="header.field.registry">
    43144230<t>
    43154231   HTTP header fields are registered within the Message Header Field Registry
    4316    located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/>
    4317    (see <xref target="RFC3864"/>).  The Message Header Field Registry
    4318    shall be updated with the permanent registrations below:
     4232   located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/>,
     4233   as defined by <xref target="RFC3864"/>.
     4234</t>
     4235
     4236<section title="Considerations for New Header Fields" anchor="considerations.for.new.header.fields">
     4237<t>
     4238   The requirements for header field names are defined in
     4239   <xref target="RFC3864" x:fmt="of" x:sec="4.1"/>.  Authors of specifications
     4240   defining new fields are advised to keep the name as short as practical, and
     4241   not to prefix them with "X-" if they are to be registered (either
     4242   immediately or in the future).
     4243</t>
     4244<t>
     4245   New header field values typically have their syntax defined using ABNF
     4246   (<xref target="RFC5234"/>), using the extension defined in &abnf-extension;
     4247   as necessary, and are usually constrained to the range of ASCII characters.
     4248   Header fields needing a greater range of characters can use an encoding
     4249   such as the one defined in <xref target="RFC5987"/>.
     4250</t>
     4251<t>
     4252   Because commas (",") are used as a generic delimiter between field-values,
     4253   they need to be treated with care if they are allowed in the field-value's
     4254   payload. Typically, components that might contain a comma are protected with
     4255   double-quotes using the quoted-string ABNF production (&field-components;).
     4256</t>
     4257<t>
     4258   For example, a textual date and a URI (either of which might contain a comma)
     4259   could be safely carried in field-values like these:
     4260</t>
     4261<figure><artwork type="example">
     4262  Example-URI-Field: "http://example.com/a.html,foo",
     4263                     "http://without-a-comma.example.com/"
     4264  Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005"
     4265</artwork></figure>
     4266<t>
     4267   Note that double-quote delimiters almost always are used with the
     4268   quoted-string production; using a different syntax inside double-quotes
     4269   will likely cause unnecessary confusion.
     4270</t>
     4271<t>
     4272   Many header fields use a format including (case-insensitively) named
     4273   parameters (for instance, <x:ref>Content-Type</x:ref>, defined in
     4274   &header-content-type;). Allowing both unquoted (token) and quoted
     4275   (quoted-string) syntax for the parameter value enables recipients to use
     4276   existing parser components. When allowing both forms, the meaning of a
     4277   parameter value ought to be independent of the syntax used for it (for an
     4278   example, see the notes on parameter handling for media types in
     4279   &media-types;).
     4280</t>
     4281<t>
     4282   Authors of specifications defining new header fields are advised to consider
     4283   documenting:
     4284  <list style="symbols">
     4285    <x:lt>
     4286      <t>Whether the field is a single value, or whether it can be a list
     4287      (delimited by commas; see &header-fields;).</t>
     4288      <t>If it does not use the list syntax, document how to treat messages
     4289      where the header field occurs multiple times (a sensible default would
     4290      be to ignore the header field, but this might not always be the right
     4291      choice).</t>
     4292      <t>Note that intermediaries and software libraries might combine
     4293      multiple header field instances into a single one, despite the header
     4294      field not allowing this. A robust format enables recipients to discover
     4295      these situations (good example: "Content-Type", as the comma can only
     4296      appear inside quoted strings; bad example: "Location", as a comma can
     4297      occur inside a URI).</t>
     4298    </x:lt>
     4299    <x:lt><t>Under what conditions the header field can be used; e.g., only in
     4300    responses or requests, in all messages, only on responses to a particular
     4301    request method.</t></x:lt>
     4302    <x:lt><t>Whether it is appropriate to list the field-name in the
     4303    <x:ref>Connection</x:ref> header field (i.e., if the header field is to
     4304    be hop-by-hop, see &header-connection;).</t></x:lt>
     4305    <x:lt><t>Under what conditions intermediaries are allowed to modify the header
     4306    field's value, insert or delete it.</t></x:lt>
     4307    <x:lt><t>How the header field might interact with caching (see
     4308    <xref target="Part6"/>).</t></x:lt>
     4309    <x:lt><t>Whether the header field is useful or allowable in trailers (see
     4310    &chunked-encoding;).</t></x:lt>
     4311    <x:lt><t>Whether the header field ought to be preserved across redirects.</t></x:lt>
     4312  </list>
     4313</t>
     4314</section>
     4315
     4316<section title="Registrations" anchor="header.field.registration">
     4317<t>
     4318   The Message Header Field Registry shall be updated with the
     4319   following permanent registrations:
    43194320</t>
    43204321<?BEGININC p2-semantics.iana-headers ?>
    … …  
    44484449</t>
    44494450</section>
     4451</section>
    44504452
    44514453<section title="Content Coding Registry" anchor="content.coding.registry">
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