Changeset 389


Ignore:
Timestamp:
Nov 14, 2008, 4:20:37 PM (11 years ago)
Author:
julian.reschke@…
Message:

move ABNF section up

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

Legend:

Unmodified
Added
Removed
  • draft-ietf-httpbis/latest/p1-messaging.html

    r385 r389  
    365365      <link rel="Index" href="#rfc.index">
    366366      <link rel="Chapter" title="1 Introduction" href="#rfc.section.1">
    367       <link rel="Chapter" title="2 Notational Conventions and Generic Grammar" href="#rfc.section.2">
    368       <link rel="Chapter" title="3 Protocol Parameters" href="#rfc.section.3">
    369       <link rel="Chapter" title="4 HTTP Message" href="#rfc.section.4">
    370       <link rel="Chapter" title="5 Request" href="#rfc.section.5">
    371       <link rel="Chapter" title="6 Response" href="#rfc.section.6">
    372       <link rel="Chapter" title="7 Connections" href="#rfc.section.7">
    373       <link rel="Chapter" title="8 Header Field Definitions" href="#rfc.section.8">
    374       <link rel="Chapter" title="9 IANA Considerations" href="#rfc.section.9">
    375       <link rel="Chapter" title="10 Security Considerations" href="#rfc.section.10">
    376       <link rel="Chapter" title="11 Acknowledgments" href="#rfc.section.11">
    377       <link rel="Chapter" href="#rfc.section.12" title="12 References">
     367      <link rel="Chapter" title="2 Protocol Parameters" href="#rfc.section.2">
     368      <link rel="Chapter" title="3 HTTP Message" href="#rfc.section.3">
     369      <link rel="Chapter" title="4 Request" href="#rfc.section.4">
     370      <link rel="Chapter" title="5 Response" href="#rfc.section.5">
     371      <link rel="Chapter" title="6 Connections" href="#rfc.section.6">
     372      <link rel="Chapter" title="7 Header Field Definitions" href="#rfc.section.7">
     373      <link rel="Chapter" title="8 IANA Considerations" href="#rfc.section.8">
     374      <link rel="Chapter" title="9 Security Considerations" href="#rfc.section.9">
     375      <link rel="Chapter" title="10 Acknowledgments" href="#rfc.section.10">
     376      <link rel="Chapter" href="#rfc.section.11" title="11 References">
    378377      <link rel="Appendix" title="A Tolerant Applications" href="#rfc.section.A">
    379378      <link rel="Appendix" title="B Compatibility with Previous Versions" href="#rfc.section.B">
     
    476475         <tr>
    477476            <td class="header left"></td>
    478             <td class="header right">November 14, 2008</td>
     477            <td class="header right">November 15, 2008</td>
    479478         </tr>
    480479      </table>
     
    516515         <li class="tocline0">1.&nbsp;&nbsp;&nbsp;<a href="#introduction">Introduction</a><ul class="toc">
    517516               <li class="tocline1">1.1&nbsp;&nbsp;&nbsp;<a href="#intro.requirements">Requirements</a></li>
    518                <li class="tocline1">1.2&nbsp;&nbsp;&nbsp;<a href="#intro.overall.operation">Overall Operation</a></li>
    519             </ul>
    520          </li>
    521          <li class="tocline0">2.&nbsp;&nbsp;&nbsp;<a href="#notation">Notational Conventions and Generic Grammar</a><ul class="toc">
    522                <li class="tocline1">2.1&nbsp;&nbsp;&nbsp;<a href="#notation.abnf">ABNF Extension: #rule</a></li>
    523                <li class="tocline1">2.2&nbsp;&nbsp;&nbsp;<a href="#basic.rules">Basic Rules</a></li>
    524                <li class="tocline1">2.3&nbsp;&nbsp;&nbsp;<a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></li>
    525             </ul>
    526          </li>
    527          <li class="tocline0">3.&nbsp;&nbsp;&nbsp;<a href="#protocol.parameters">Protocol Parameters</a><ul class="toc">
    528                <li class="tocline1">3.1&nbsp;&nbsp;&nbsp;<a href="#http.version">HTTP Version</a></li>
    529                <li class="tocline1">3.2&nbsp;&nbsp;&nbsp;<a href="#uri">Uniform Resource Identifiers</a><ul class="toc">
    530                      <li class="tocline1">3.2.1&nbsp;&nbsp;&nbsp;<a href="#http.uri">http URI scheme</a></li>
    531                      <li class="tocline1">3.2.2&nbsp;&nbsp;&nbsp;<a href="#uri.comparison">URI Comparison</a></li>
     517               <li class="tocline1">1.2&nbsp;&nbsp;&nbsp;<a href="#notation">Notational Conventions and Generic Grammar</a><ul class="toc">
     518                     <li class="tocline1">1.2.1&nbsp;&nbsp;&nbsp;<a href="#notation.abnf">ABNF Extension: #rule</a></li>
     519                     <li class="tocline1">1.2.2&nbsp;&nbsp;&nbsp;<a href="#basic.rules">Basic Rules</a></li>
     520                     <li class="tocline1">1.2.3&nbsp;&nbsp;&nbsp;<a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></li>
    532521                  </ul>
    533522               </li>
    534                <li class="tocline1">3.3&nbsp;&nbsp;&nbsp;<a href="#date.time.formats">Date/Time Formats</a><ul class="toc">
    535                      <li class="tocline1">3.3.1&nbsp;&nbsp;&nbsp;<a href="#full.date">Full Date</a></li>
     523               <li class="tocline1">1.3&nbsp;&nbsp;&nbsp;<a href="#intro.overall.operation">Overall Operation</a></li>
     524            </ul>
     525         </li>
     526         <li class="tocline0">2.&nbsp;&nbsp;&nbsp;<a href="#protocol.parameters">Protocol Parameters</a><ul class="toc">
     527               <li class="tocline1">2.1&nbsp;&nbsp;&nbsp;<a href="#http.version">HTTP Version</a></li>
     528               <li class="tocline1">2.2&nbsp;&nbsp;&nbsp;<a href="#uri">Uniform Resource Identifiers</a><ul class="toc">
     529                     <li class="tocline1">2.2.1&nbsp;&nbsp;&nbsp;<a href="#http.uri">http URI scheme</a></li>
     530                     <li class="tocline1">2.2.2&nbsp;&nbsp;&nbsp;<a href="#uri.comparison">URI Comparison</a></li>
    536531                  </ul>
    537532               </li>
    538                <li class="tocline1">3.4&nbsp;&nbsp;&nbsp;<a href="#transfer.codings">Transfer Codings</a><ul class="toc">
    539                      <li class="tocline1">3.4.1&nbsp;&nbsp;&nbsp;<a href="#chunked.transfer.encoding">Chunked Transfer Coding</a></li>
     533               <li class="tocline1">2.3&nbsp;&nbsp;&nbsp;<a href="#date.time.formats">Date/Time Formats</a><ul class="toc">
     534                     <li class="tocline1">2.3.1&nbsp;&nbsp;&nbsp;<a href="#full.date">Full Date</a></li>
    540535                  </ul>
    541536               </li>
    542                <li class="tocline1">3.5&nbsp;&nbsp;&nbsp;<a href="#product.tokens">Product Tokens</a></li>
    543             </ul>
    544          </li>
    545          <li class="tocline0">4.&nbsp;&nbsp;&nbsp;<a href="#http.message">HTTP Message</a><ul class="toc">
    546                <li class="tocline1">4.1&nbsp;&nbsp;&nbsp;<a href="#message.types">Message Types</a></li>
    547                <li class="tocline1">4.2&nbsp;&nbsp;&nbsp;<a href="#message.headers">Message Headers</a></li>
    548                <li class="tocline1">4.3&nbsp;&nbsp;&nbsp;<a href="#message.body">Message Body</a></li>
    549                <li class="tocline1">4.4&nbsp;&nbsp;&nbsp;<a href="#message.length">Message Length</a></li>
    550                <li class="tocline1">4.5&nbsp;&nbsp;&nbsp;<a href="#general.header.fields">General Header Fields</a></li>
    551             </ul>
    552          </li>
    553          <li class="tocline0">5.&nbsp;&nbsp;&nbsp;<a href="#request">Request</a><ul class="toc">
    554                <li class="tocline1">5.1&nbsp;&nbsp;&nbsp;<a href="#request-line">Request-Line</a><ul class="toc">
    555                      <li class="tocline1">5.1.1&nbsp;&nbsp;&nbsp;<a href="#method">Method</a></li>
    556                      <li class="tocline1">5.1.2&nbsp;&nbsp;&nbsp;<a href="#request-uri">Request-URI</a></li>
     537               <li class="tocline1">2.4&nbsp;&nbsp;&nbsp;<a href="#transfer.codings">Transfer Codings</a><ul class="toc">
     538                     <li class="tocline1">2.4.1&nbsp;&nbsp;&nbsp;<a href="#chunked.transfer.encoding">Chunked Transfer Coding</a></li>
    557539                  </ul>
    558540               </li>
    559                <li class="tocline1">5.2&nbsp;&nbsp;&nbsp;<a href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></li>
     541               <li class="tocline1">2.5&nbsp;&nbsp;&nbsp;<a href="#product.tokens">Product Tokens</a></li>
    560542            </ul>
    561543         </li>
    562          <li class="tocline0">6.&nbsp;&nbsp;&nbsp;<a href="#response">Response</a><ul class="toc">
    563                <li class="tocline1">6.1&nbsp;&nbsp;&nbsp;<a href="#status-line">Status-Line</a><ul class="toc">
    564                      <li class="tocline1">6.1.1&nbsp;&nbsp;&nbsp;<a href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></li>
     544         <li class="tocline0">3.&nbsp;&nbsp;&nbsp;<a href="#http.message">HTTP Message</a><ul class="toc">
     545               <li class="tocline1">3.1&nbsp;&nbsp;&nbsp;<a href="#message.types">Message Types</a></li>
     546               <li class="tocline1">3.2&nbsp;&nbsp;&nbsp;<a href="#message.headers">Message Headers</a></li>
     547               <li class="tocline1">3.3&nbsp;&nbsp;&nbsp;<a href="#message.body">Message Body</a></li>
     548               <li class="tocline1">3.4&nbsp;&nbsp;&nbsp;<a href="#message.length">Message Length</a></li>
     549               <li class="tocline1">3.5&nbsp;&nbsp;&nbsp;<a href="#general.header.fields">General Header Fields</a></li>
     550            </ul>
     551         </li>
     552         <li class="tocline0">4.&nbsp;&nbsp;&nbsp;<a href="#request">Request</a><ul class="toc">
     553               <li class="tocline1">4.1&nbsp;&nbsp;&nbsp;<a href="#request-line">Request-Line</a><ul class="toc">
     554                     <li class="tocline1">4.1.1&nbsp;&nbsp;&nbsp;<a href="#method">Method</a></li>
     555                     <li class="tocline1">4.1.2&nbsp;&nbsp;&nbsp;<a href="#request-uri">Request-URI</a></li>
     556                  </ul>
     557               </li>
     558               <li class="tocline1">4.2&nbsp;&nbsp;&nbsp;<a href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></li>
     559            </ul>
     560         </li>
     561         <li class="tocline0">5.&nbsp;&nbsp;&nbsp;<a href="#response">Response</a><ul class="toc">
     562               <li class="tocline1">5.1&nbsp;&nbsp;&nbsp;<a href="#status-line">Status-Line</a><ul class="toc">
     563                     <li class="tocline1">5.1.1&nbsp;&nbsp;&nbsp;<a href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></li>
    565564                  </ul>
    566565               </li>
    567566            </ul>
    568567         </li>
    569          <li class="tocline0">7.&nbsp;&nbsp;&nbsp;<a href="#connections">Connections</a><ul class="toc">
    570                <li class="tocline1">7.1&nbsp;&nbsp;&nbsp;<a href="#persistent.connections">Persistent Connections</a><ul class="toc">
    571                      <li class="tocline1">7.1.1&nbsp;&nbsp;&nbsp;<a href="#persistent.purpose">Purpose</a></li>
    572                      <li class="tocline1">7.1.2&nbsp;&nbsp;&nbsp;<a href="#persistent.overall">Overall Operation</a><ul class="toc">
    573                            <li class="tocline1">7.1.2.1&nbsp;&nbsp;&nbsp;<a href="#persistent.negotiation">Negotiation</a></li>
    574                            <li class="tocline1">7.1.2.2&nbsp;&nbsp;&nbsp;<a href="#pipelining">Pipelining</a></li>
     568         <li class="tocline0">6.&nbsp;&nbsp;&nbsp;<a href="#connections">Connections</a><ul class="toc">
     569               <li class="tocline1">6.1&nbsp;&nbsp;&nbsp;<a href="#persistent.connections">Persistent Connections</a><ul class="toc">
     570                     <li class="tocline1">6.1.1&nbsp;&nbsp;&nbsp;<a href="#persistent.purpose">Purpose</a></li>
     571                     <li class="tocline1">6.1.2&nbsp;&nbsp;&nbsp;<a href="#persistent.overall">Overall Operation</a><ul class="toc">
     572                           <li class="tocline1">6.1.2.1&nbsp;&nbsp;&nbsp;<a href="#persistent.negotiation">Negotiation</a></li>
     573                           <li class="tocline1">6.1.2.2&nbsp;&nbsp;&nbsp;<a href="#pipelining">Pipelining</a></li>
    575574                        </ul>
    576575                     </li>
    577                      <li class="tocline1">7.1.3&nbsp;&nbsp;&nbsp;<a href="#persistent.proxy">Proxy Servers</a></li>
    578                      <li class="tocline1">7.1.4&nbsp;&nbsp;&nbsp;<a href="#persistent.practical">Practical Considerations</a></li>
     576                     <li class="tocline1">6.1.3&nbsp;&nbsp;&nbsp;<a href="#persistent.proxy">Proxy Servers</a></li>
     577                     <li class="tocline1">6.1.4&nbsp;&nbsp;&nbsp;<a href="#persistent.practical">Practical Considerations</a></li>
    579578                  </ul>
    580579               </li>
    581                <li class="tocline1">7.2&nbsp;&nbsp;&nbsp;<a href="#message.transmission.requirements">Message Transmission Requirements</a><ul class="toc">
    582                      <li class="tocline1">7.2.1&nbsp;&nbsp;&nbsp;<a href="#persistent.flow">Persistent Connections and Flow Control</a></li>
    583                      <li class="tocline1">7.2.2&nbsp;&nbsp;&nbsp;<a href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></li>
    584                      <li class="tocline1">7.2.3&nbsp;&nbsp;&nbsp;<a href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></li>
    585                      <li class="tocline1">7.2.4&nbsp;&nbsp;&nbsp;<a href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></li>
     580               <li class="tocline1">6.2&nbsp;&nbsp;&nbsp;<a href="#message.transmission.requirements">Message Transmission Requirements</a><ul class="toc">
     581                     <li class="tocline1">6.2.1&nbsp;&nbsp;&nbsp;<a href="#persistent.flow">Persistent Connections and Flow Control</a></li>
     582                     <li class="tocline1">6.2.2&nbsp;&nbsp;&nbsp;<a href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></li>
     583                     <li class="tocline1">6.2.3&nbsp;&nbsp;&nbsp;<a href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></li>
     584                     <li class="tocline1">6.2.4&nbsp;&nbsp;&nbsp;<a href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></li>
    586585                  </ul>
    587586               </li>
    588587            </ul>
    589588         </li>
    590          <li class="tocline0">8.&nbsp;&nbsp;&nbsp;<a href="#header.fields">Header Field Definitions</a><ul class="toc">
    591                <li class="tocline1">8.1&nbsp;&nbsp;&nbsp;<a href="#header.connection">Connection</a></li>
    592                <li class="tocline1">8.2&nbsp;&nbsp;&nbsp;<a href="#header.content-length">Content-Length</a></li>
    593                <li class="tocline1">8.3&nbsp;&nbsp;&nbsp;<a href="#header.date">Date</a><ul class="toc">
    594                      <li class="tocline1">8.3.1&nbsp;&nbsp;&nbsp;<a href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></li>
     589         <li class="tocline0">7.&nbsp;&nbsp;&nbsp;<a href="#header.fields">Header Field Definitions</a><ul class="toc">
     590               <li class="tocline1">7.1&nbsp;&nbsp;&nbsp;<a href="#header.connection">Connection</a></li>
     591               <li class="tocline1">7.2&nbsp;&nbsp;&nbsp;<a href="#header.content-length">Content-Length</a></li>
     592               <li class="tocline1">7.3&nbsp;&nbsp;&nbsp;<a href="#header.date">Date</a><ul class="toc">
     593                     <li class="tocline1">7.3.1&nbsp;&nbsp;&nbsp;<a href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></li>
    595594                  </ul>
    596595               </li>
    597                <li class="tocline1">8.4&nbsp;&nbsp;&nbsp;<a href="#header.host">Host</a></li>
    598                <li class="tocline1">8.5&nbsp;&nbsp;&nbsp;<a href="#header.te">TE</a></li>
    599                <li class="tocline1">8.6&nbsp;&nbsp;&nbsp;<a href="#header.trailer">Trailer</a></li>
    600                <li class="tocline1">8.7&nbsp;&nbsp;&nbsp;<a href="#header.transfer-encoding">Transfer-Encoding</a></li>
    601                <li class="tocline1">8.8&nbsp;&nbsp;&nbsp;<a href="#header.upgrade">Upgrade</a></li>
    602                <li class="tocline1">8.9&nbsp;&nbsp;&nbsp;<a href="#header.via">Via</a></li>
     596               <li class="tocline1">7.4&nbsp;&nbsp;&nbsp;<a href="#header.host">Host</a></li>
     597               <li class="tocline1">7.5&nbsp;&nbsp;&nbsp;<a href="#header.te">TE</a></li>
     598               <li class="tocline1">7.6&nbsp;&nbsp;&nbsp;<a href="#header.trailer">Trailer</a></li>
     599               <li class="tocline1">7.7&nbsp;&nbsp;&nbsp;<a href="#header.transfer-encoding">Transfer-Encoding</a></li>
     600               <li class="tocline1">7.8&nbsp;&nbsp;&nbsp;<a href="#header.upgrade">Upgrade</a></li>
     601               <li class="tocline1">7.9&nbsp;&nbsp;&nbsp;<a href="#header.via">Via</a></li>
    603602            </ul>
    604603         </li>
    605          <li class="tocline0">9.&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul class="toc">
    606                <li class="tocline1">9.1&nbsp;&nbsp;&nbsp;<a href="#message.header.registration">Message Header Registration</a></li>
    607                <li class="tocline1">9.2&nbsp;&nbsp;&nbsp;<a href="#uri.scheme.registration">URI Scheme Registration</a></li>
    608                <li class="tocline1">9.3&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.http">Internet Media Type Registrations</a><ul class="toc">
    609                      <li class="tocline1">9.3.1&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.message.http">Internet Media Type message/http</a></li>
    610                      <li class="tocline1">9.3.2&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.application.http">Internet Media Type application/http</a></li>
     604         <li class="tocline0">8.&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul class="toc">
     605               <li class="tocline1">8.1&nbsp;&nbsp;&nbsp;<a href="#message.header.registration">Message Header Registration</a></li>
     606               <li class="tocline1">8.2&nbsp;&nbsp;&nbsp;<a href="#uri.scheme.registration">URI Scheme Registration</a></li>
     607               <li class="tocline1">8.3&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.http">Internet Media Type Registrations</a><ul class="toc">
     608                     <li class="tocline1">8.3.1&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.message.http">Internet Media Type message/http</a></li>
     609                     <li class="tocline1">8.3.2&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.application.http">Internet Media Type application/http</a></li>
    611610                  </ul>
    612611               </li>
    613612            </ul>
    614613         </li>
    615          <li class="tocline0">10.&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul class="toc">
    616                <li class="tocline1">10.1&nbsp;&nbsp;&nbsp;<a href="#personal.information">Personal Information</a></li>
    617                <li class="tocline1">10.2&nbsp;&nbsp;&nbsp;<a href="#abuse.of.server.log.information">Abuse of Server Log Information</a></li>
    618                <li class="tocline1">10.3&nbsp;&nbsp;&nbsp;<a href="#attack.pathname">Attacks Based On File and Path Names</a></li>
    619                <li class="tocline1">10.4&nbsp;&nbsp;&nbsp;<a href="#dns.spoofing">DNS Spoofing</a></li>
    620                <li class="tocline1">10.5&nbsp;&nbsp;&nbsp;<a href="#attack.proxies">Proxies and Caching</a></li>
    621                <li class="tocline1">10.6&nbsp;&nbsp;&nbsp;<a href="#attack.DoS">Denial of Service Attacks on Proxies</a></li>
     614         <li class="tocline0">9.&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul class="toc">
     615               <li class="tocline1">9.1&nbsp;&nbsp;&nbsp;<a href="#personal.information">Personal Information</a></li>
     616               <li class="tocline1">9.2&nbsp;&nbsp;&nbsp;<a href="#abuse.of.server.log.information">Abuse of Server Log Information</a></li>
     617               <li class="tocline1">9.3&nbsp;&nbsp;&nbsp;<a href="#attack.pathname">Attacks Based On File and Path Names</a></li>
     618               <li class="tocline1">9.4&nbsp;&nbsp;&nbsp;<a href="#dns.spoofing">DNS Spoofing</a></li>
     619               <li class="tocline1">9.5&nbsp;&nbsp;&nbsp;<a href="#attack.proxies">Proxies and Caching</a></li>
     620               <li class="tocline1">9.6&nbsp;&nbsp;&nbsp;<a href="#attack.DoS">Denial of Service Attacks on Proxies</a></li>
    622621            </ul>
    623622         </li>
    624          <li class="tocline0">11.&nbsp;&nbsp;&nbsp;<a href="#ack">Acknowledgments</a></li>
    625          <li class="tocline0">12.&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul class="toc">
    626                <li class="tocline1">12.1&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
    627                <li class="tocline1">12.2&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
     623         <li class="tocline0">10.&nbsp;&nbsp;&nbsp;<a href="#ack">Acknowledgments</a></li>
     624         <li class="tocline0">11.&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul class="toc">
     625               <li class="tocline1">11.1&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
     626               <li class="tocline1">11.2&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
    628627            </ul>
    629628         </li>
     
    675674      <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level requirements for the protocols it implements. An implementation that satisfies all the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level and all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "unconditionally compliant"; one that satisfies all the <em class="bcp14">MUST</em> level requirements but not all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "conditionally compliant."
    676675      </p>
    677       <h2 id="rfc.section.1.2"><a href="#rfc.section.1.2">1.2</a>&nbsp;<a id="intro.overall.operation" href="#intro.overall.operation">Overall Operation</a></h2>
    678       <p id="rfc.section.1.2.p.1">HTTP is a request/response protocol. A client sends a request to the server in the form of a request method, URI, and protocol
    679          version, followed by a MIME-like message containing request modifiers, client information, and possible body content over
    680          a connection with a server. The server responds with a status line, including the message's protocol version and a success
    681          or error code, followed by a MIME-like message containing server information, entity metainformation, and possible entity-body
    682          content. The relationship between HTTP and MIME is described in <a href="p3-payload.html#differences.between.http.entities.and.rfc.2045.entities" title="Differences Between HTTP Entities and RFC 2045 Entities">Appendix A</a> of <a href="#Part3" id="rfc.xref.Part3.2"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.
    683       </p>
    684       <p id="rfc.section.1.2.p.2">Most HTTP communication is initiated by a user agent and consists of a request to be applied to a resource on some origin
    685          server. In the simplest case, this may be accomplished via a single connection (v) between the user agent (UA) and the origin
    686          server (O).
    687       </p>
    688       <div id="rfc.figure.u.1"></div><pre class="drawing">       request chain ------------------------&gt;
    689     UA -------------------v------------------- O
    690        &lt;----------------------- response chain
    691 </pre><p id="rfc.section.1.2.p.4">A more complicated situation occurs when one or more intermediaries are present in the request/response chain. There are three
    692          common forms of intermediary: proxy, gateway, and tunnel. A proxy is a forwarding agent, receiving requests for a URI in its
    693          absolute form, rewriting all or part of the message, and forwarding the reformatted request toward the server identified by
    694          the URI. A gateway is a receiving agent, acting as a layer above some other server(s) and, if necessary, translating the requests
    695          to the underlying server's protocol. A tunnel acts as a relay point between two connections without changing the messages;
    696          tunnels are used when the communication needs to pass through an intermediary (such as a firewall) even when the intermediary
    697          cannot understand the contents of the messages.
    698       </p>
    699       <div id="rfc.figure.u.2"></div><pre class="drawing">       request chain --------------------------------------&gt;
    700     UA -----v----- A -----v----- B -----v----- C -----v----- O
    701        &lt;------------------------------------- response chain
    702 </pre><p id="rfc.section.1.2.p.6">The figure above shows three intermediaries (A, B, and C) between the user agent and origin server. A request or response
    703          message that travels the whole chain will pass through four separate connections. This distinction is important because some
    704          HTTP communication options may apply only to the connection with the nearest, non-tunnel neighbor, only to the end-points
    705          of the chain, or to all connections along the chain. Although the diagram is linear, each participant may be engaged in multiple,
    706          simultaneous communications. For example, B may be receiving requests from many clients other than A, and/or forwarding requests
    707          to servers other than C, at the same time that it is handling A's request.
    708       </p>
    709       <p id="rfc.section.1.2.p.7">Any party to the communication which is not acting as a tunnel may employ an internal cache for handling requests. The effect
    710          of a cache is that the request/response chain is shortened if one of the participants along the chain has a cached response
    711          applicable to that request. The following illustrates the resulting chain if B has a cached copy of an earlier response from
    712          O (via C) for a request which has not been cached by UA or A.
    713       </p>
    714       <div id="rfc.figure.u.3"></div><pre class="drawing">          request chain ----------&gt;
    715        UA -----v----- A -----v----- B - - - - - - C - - - - - - O
    716           &lt;--------- response chain
    717 </pre><p id="rfc.section.1.2.p.9">Not all responses are usefully cacheable, and some requests may contain modifiers which place special requirements on cache
    718          behavior. HTTP requirements for cache behavior and cacheable responses are defined in <a href="p6-cache.html#caching" title="Introduction">Section 1</a> of <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>.
    719       </p>
    720       <p id="rfc.section.1.2.p.10">In fact, there are a wide variety of architectures and configurations of caches and proxies currently being experimented with
    721          or deployed across the World Wide Web. These systems include national hierarchies of proxy caches to save transoceanic bandwidth,
    722          systems that broadcast or multicast cache entries, organizations that distribute subsets of cached data via CD-ROM, and so
    723          on. HTTP systems are used in corporate intranets over high-bandwidth links, and for access via PDAs with low-power radio links
    724          and intermittent connectivity. The goal of HTTP/1.1 is to support the wide diversity of configurations already deployed while
    725          introducing protocol constructs that meet the needs of those who build web applications that require high reliability and,
    726          failing that, at least reliable indications of failure.
    727       </p>
    728       <p id="rfc.section.1.2.p.11">HTTP communication usually takes place over TCP/IP connections. The default port is TCP 80 (&lt;<a href="http://www.iana.org/assignments/port-numbers">http://www.iana.org/assignments/port-numbers</a>&gt;), but other ports can be used. This does not preclude HTTP from being implemented on top of any other protocol on the Internet,
    729          or on other networks. HTTP only presumes a reliable transport; any protocol that provides such guarantees can be used; the
    730          mapping of the HTTP/1.1 request and response structures onto the transport data units of the protocol in question is outside
    731          the scope of this specification.
    732       </p>
    733       <p id="rfc.section.1.2.p.12">In HTTP/1.0, most implementations used a new connection for each request/response exchange. In HTTP/1.1, a connection may
    734          be used for one or more request/response exchanges, although connections may be closed for a variety of reasons (see <a href="#persistent.connections" title="Persistent Connections">Section&nbsp;7.1</a>).
    735       </p>
    736       <h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a id="notation" href="#notation">Notational Conventions and Generic Grammar</a></h1>
    737       <h2 id="rfc.section.2.1"><a href="#rfc.section.2.1">2.1</a>&nbsp;<a id="notation.abnf" href="#notation.abnf">ABNF Extension: #rule</a></h2>
    738       <p id="rfc.section.2.1.p.1">One extension to the ABNF rules of <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> is used to improve readability.
    739       </p>
    740       <p id="rfc.section.2.1.p.2">A construct "#" is defined, similar to "*", for defining lists of elements. The full form is "&lt;n&gt;#&lt;m&gt;element" indicating at
     676      <h2 id="rfc.section.1.2"><a href="#rfc.section.1.2">1.2</a>&nbsp;<a id="notation" href="#notation">Notational Conventions and Generic Grammar</a></h2>
     677      <h3 id="rfc.section.1.2.1"><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;<a id="notation.abnf" href="#notation.abnf">ABNF Extension: #rule</a></h3>
     678      <p id="rfc.section.1.2.1.p.1">One extension to the ABNF rules of <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> is used to improve readability.
     679      </p>
     680      <p id="rfc.section.1.2.1.p.2">A construct "#" is defined, similar to "*", for defining lists of elements. The full form is "&lt;n&gt;#&lt;m&gt;element" indicating at
    741681         least &lt;n&gt; and at most &lt;m&gt; elements, each separated by one or more commas (",") and <em class="bcp14">OPTIONAL</em> linear white space (OWS). This makes the usual form of lists very easy; a rule such as
    742682      </p>
    743       <div id="rfc.figure.u.4"></div><pre class="text"> ( *<a href="#rule.whitespace" class="smpl">OWS</a> element *( *<a href="#rule.whitespace" class="smpl">OWS</a> "," *<a href="#rule.whitespace" class="smpl">OWS</a> element ))</pre><p id="rfc.section.2.1.p.3">can be shown as </p>
    744       <div id="rfc.figure.u.5"></div><pre class="text"> 1#element</pre><p id="rfc.section.2.1.p.4">Wherever this construct is used, null elements are allowed, but do not contribute to the count of elements present. That is,
     683      <div id="rfc.figure.u.1"></div><pre class="text"> ( *<a href="#rule.whitespace" class="smpl">OWS</a> element *( *<a href="#rule.whitespace" class="smpl">OWS</a> "," *<a href="#rule.whitespace" class="smpl">OWS</a> element ))</pre><p id="rfc.section.1.2.1.p.3">can be shown as </p>
     684      <div id="rfc.figure.u.2"></div><pre class="text"> 1#element</pre><p id="rfc.section.1.2.1.p.4">Wherever this construct is used, null elements are allowed, but do not contribute to the count of elements present. That is,
    745685         "(element), , (element) " is permitted, but counts as only two elements. Therefore, where at least one element is required,
    746686         at least one non-null element <em class="bcp14">MUST</em> be present. Default values are 0 and infinity so that "#element" allows any number, including zero; "1#element" requires at
    747687         least one; and "1#2element" allows one or two.
    748688      </p>
    749       <p id="rfc.section.2.1.p.5"> <span class="comment">[abnf.list: At a later point of time, we may want to add an appendix containing the whole ABNF, with the list rules expanded to strict
     689      <p id="rfc.section.1.2.1.p.5"> <span class="comment">[abnf.list: At a later point of time, we may want to add an appendix containing the whole ABNF, with the list rules expanded to strict
    750690            RFC 5234 notation.]</span>
    751691      </p>
    752       <h2 id="rfc.section.2.2"><a href="#rfc.section.2.2">2.2</a>&nbsp;<a id="basic.rules" href="#basic.rules">Basic Rules</a></h2>
     692      <h3 id="rfc.section.1.2.2"><a href="#rfc.section.1.2.2">1.2.2</a>&nbsp;<a id="basic.rules" href="#basic.rules">Basic Rules</a></h3>
    753693      <div id="core.rules">
    754          <p id="rfc.section.2.2.p.1">                          This specification uses the Augmented Backus-Naur Form (ABNF) notation of <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. The following core rules are included by reference, as defined in <a href="#RFC5234" id="rfc.xref.RFC5234.3"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, <a href="http://tools.ietf.org/html/rfc5234#section-B.1">Appendix B.1</a>: ALPHA (letters), CHAR (any <a href="#USASCII" id="rfc.xref.USASCII.1"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a> character, excluding NUL), CR (carriage return), CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),
     694         <p id="rfc.section.1.2.2.p.1">                          This specification uses the Augmented Backus-Naur Form (ABNF) notation of <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. The following core rules are included by reference, as defined in <a href="#RFC5234" id="rfc.xref.RFC5234.3"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, <a href="http://tools.ietf.org/html/rfc5234#section-B.1">Appendix B.1</a>: ALPHA (letters), CHAR (any <a href="#USASCII" id="rfc.xref.USASCII.1"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a> character, excluding NUL), CR (carriage return), CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),
    755695            HEXDIG (hexadecimal 0-9/A-F/a-f), HTAB (horizontal tab), LF (line feed), OCTET (any 8-bit sequence of data), SP (space) and
    756696            WSP (white space).
     
    758698      </div>
    759699      <div id="rule.CRLF">
    760          <p id="rfc.section.2.2.p.2">  HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all protocol elements except the entity-body (see <a href="#tolerant.applications" title="Tolerant Applications">Appendix&nbsp;A</a> for tolerant applications). The end-of-line marker within an entity-body is defined by its associated media type, as described
    761             in <a href="p3-payload.html#media.types" title="Media Types">Section 3.3</a> of <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.
     700         <p id="rfc.section.1.2.2.p.2">  HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all protocol elements except the entity-body (see <a href="#tolerant.applications" title="Tolerant Applications">Appendix&nbsp;A</a> for tolerant applications). The end-of-line marker within an entity-body is defined by its associated media type, as described
     701            in <a href="p3-payload.html#media.types" title="Media Types">Section 3.3</a> of <a href="#Part3" id="rfc.xref.Part3.2"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.
    762702         </p>
    763703      </div>
    764704      <div id="rule.LWS">
    765          <p id="rfc.section.2.2.p.3">All linear white space (LWS) in header field-values has the same semantics as SP. A recipient <em class="bcp14">MAY</em> replace any such linear white space with a single SP before interpreting the field value or forwarding the message downstream.
     705         <p id="rfc.section.1.2.2.p.3">All linear white space (LWS) in header field-values has the same semantics as SP. A recipient <em class="bcp14">MAY</em> replace any such linear white space with a single SP before interpreting the field value or forwarding the message downstream.
    766706         </p>
    767707      </div>
    768       <p id="rfc.section.2.2.p.4">Historically, HTTP/1.1 header field values allow linear white space folding across multiple lines. However, this specification
    769          deprecates its use; senders <em class="bcp14">MUST NOT</em> produce messages that include LWS folding (i.e., use the obs-fold rule), except within the message/http media type (<a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section&nbsp;9.3.1</a>). Receivers <em class="bcp14">SHOULD</em> still parse folded linear white space.
    770       </p>
    771       <p id="rfc.section.2.2.p.5">This specification uses three rules to denote the use of linear white space; BWS ("Bad" White Space), OWS (Optional White
     708      <p id="rfc.section.1.2.2.p.4">Historically, HTTP/1.1 header field values allow linear white space folding across multiple lines. However, this specification
     709         deprecates its use; senders <em class="bcp14">MUST NOT</em> produce messages that include LWS folding (i.e., use the obs-fold rule), except within the message/http media type (<a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section&nbsp;8.3.1</a>). Receivers <em class="bcp14">SHOULD</em> still parse folded linear white space.
     710      </p>
     711      <p id="rfc.section.1.2.2.p.5">This specification uses three rules to denote the use of linear white space; BWS ("Bad" White Space), OWS (Optional White
    772712         Space), and RWS (Required White Space).
    773713      </p>
    774       <p id="rfc.section.2.2.p.6">"Bad" white space is allowed by the BNF, but senders <em class="bcp14">SHOULD NOT</em> produce it in messages. Receivers <em class="bcp14">MUST</em> accept it in incoming messages.
    775       </p>
    776       <p id="rfc.section.2.2.p.7">Required white space is used when at least one linear white space character is required to separate field tokens. In all such
     714      <p id="rfc.section.1.2.2.p.6">"Bad" white space is allowed by the BNF, but senders <em class="bcp14">SHOULD NOT</em> produce it in messages. Receivers <em class="bcp14">MUST</em> accept it in incoming messages.
     715      </p>
     716      <p id="rfc.section.1.2.2.p.7">Required white space is used when at least one linear white space character is required to separate field tokens. In all such
    777717         cases, a single SP character <em class="bcp14">SHOULD</em> be used.
    778718      </p>
    779719      <div id="rule.whitespace">
    780          <p id="rfc.section.2.2.p.8">        </p>
     720         <p id="rfc.section.1.2.2.p.8">        </p>
    781721      </div>
    782       <div id="rfc.figure.u.6"></div><pre class="inline"><span id="rfc.iref.g.1"></span><span id="rfc.iref.g.2"></span><span id="rfc.iref.g.3"></span>  <a href="#rule.whitespace" class="smpl">OWS</a>            = *( [ obs-fold ] <a href="#core.rules" class="smpl">WSP</a> )
     722      <div id="rfc.figure.u.3"></div><pre class="inline"><span id="rfc.iref.g.1"></span><span id="rfc.iref.g.2"></span><span id="rfc.iref.g.3"></span>  <a href="#rule.whitespace" class="smpl">OWS</a>            = *( [ obs-fold ] <a href="#core.rules" class="smpl">WSP</a> )
    783723                 ; "optional" white space
    784724  <a href="#rule.whitespace" class="smpl">RWS</a>            = 1*( [ obs-fold ] <a href="#core.rules" class="smpl">WSP</a> )
     
    788728  <a href="#rule.whitespace" class="smpl">obs-fold</a>       = <a href="#core.rules" class="smpl">CRLF</a>
    789729</pre><div id="rule.TEXT">
    790          <p id="rfc.section.2.2.p.10">  The TEXT rule is only used for descriptive field contents and values that are not intended to be interpreted by the message
     730         <p id="rfc.section.1.2.2.p.10">  The TEXT rule is only used for descriptive field contents and values that are not intended to be interpreted by the message
    791731            parser. Words of *TEXT <em class="bcp14">MAY</em> contain characters from character sets other than ISO-8859-1 <a href="#ISO-8859-1" id="rfc.xref.ISO-8859-1.1"><cite title="Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1">[ISO-8859-1]</cite></a> only when encoded according to the rules of <a href="#RFC2047" id="rfc.xref.RFC2047.1"><cite title="MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text">[RFC2047]</cite></a>.
    792732         </p>
    793733      </div>
    794       <div id="rfc.figure.u.7"></div><pre class="inline"><span id="rfc.iref.g.4"></span>  <a href="#rule.TEXT" class="smpl">TEXT</a>           = %x20-7E / %x80-FF / <a href="#rule.whitespace" class="smpl">OWS</a>
     734      <div id="rfc.figure.u.4"></div><pre class="inline"><span id="rfc.iref.g.4"></span>  <a href="#rule.TEXT" class="smpl">TEXT</a>           = %x20-7E / %x80-FF / <a href="#rule.whitespace" class="smpl">OWS</a>
    795735                 ; any <a href="#core.rules" class="smpl">OCTET</a> except <a href="#core.rules" class="smpl">CTL</a>s, but including <a href="#rule.whitespace" class="smpl">OWS</a>
    796 </pre><p id="rfc.section.2.2.p.12">A CRLF is allowed in the definition of TEXT only as part of a header field continuation. It is expected that the folding LWS
     736</pre><p id="rfc.section.1.2.2.p.12">A CRLF is allowed in the definition of TEXT only as part of a header field continuation. It is expected that the folding LWS
    797737         will be replaced with a single SP before interpretation of the TEXT value.
    798738      </p>
    799739      <div id="rule.token.separators">
    800          <p id="rfc.section.2.2.p.13">    Many HTTP/1.1 header field values consist of words separated by LWS or special characters. These special characters <em class="bcp14">MUST</em> be in a quoted string to be used within a parameter value (as defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.4</a>).
     740         <p id="rfc.section.1.2.2.p.13">    Many HTTP/1.1 header field values consist of words separated by LWS or special characters. These special characters <em class="bcp14">MUST</em> be in a quoted string to be used within a parameter value (as defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;2.4</a>).
    801741         </p>
    802742      </div>
    803       <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span>  <a href="#rule.token.separators" class="smpl">tchar</a>          = "!" / "#" / "$" / "%" / "&amp;" / "'" / "*"
     743      <div id="rfc.figure.u.5"></div><pre class="inline"><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span>  <a href="#rule.token.separators" class="smpl">tchar</a>          = "!" / "#" / "$" / "%" / "&amp;" / "'" / "*"
    804744                 / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
    805745                 / <a href="#core.rules" class="smpl">DIGIT</a> / <a href="#core.rules" class="smpl">ALPHA</a>
     
    807747  <a href="#rule.token.separators" class="smpl">token</a>          = 1*<a href="#rule.token.separators" class="smpl">tchar</a>
    808748</pre><div id="rule.comment">
    809          <p id="rfc.section.2.2.p.15">    Comments can be included in some HTTP header fields by surrounding the comment text with parentheses. Comments are only allowed
     749         <p id="rfc.section.1.2.2.p.15">    Comments can be included in some HTTP header fields by surrounding the comment text with parentheses. Comments are only allowed
    810750            in fields containing "comment" as part of their field value definition. In all other fields, parentheses are considered part
    811751            of the field value.
    812752         </p>
    813753      </div>
    814       <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span>  <a href="#rule.comment" class="smpl">comment</a>        = "(" *( <a href="#rule.comment" class="smpl">ctext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> / <a href="#rule.comment" class="smpl">comment</a> ) ")"
     754      <div id="rfc.figure.u.6"></div><pre class="inline"><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span>  <a href="#rule.comment" class="smpl">comment</a>        = "(" *( <a href="#rule.comment" class="smpl">ctext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> / <a href="#rule.comment" class="smpl">comment</a> ) ")"
    815755  <a href="#rule.comment" class="smpl">ctext</a>          = &lt;any <a href="#rule.TEXT" class="smpl">TEXT</a> excluding "(" and ")"&gt;
    816756</pre><div id="rule.quoted-string">
    817          <p id="rfc.section.2.2.p.17">    A string of text is parsed as a single word if it is quoted using double-quote marks.</p>
     757         <p id="rfc.section.1.2.2.p.17">    A string of text is parsed as a single word if it is quoted using double-quote marks.</p>
    818758      </div>
    819       <div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span>  <a href="#rule.quoted-string" class="smpl">quoted-string</a>  = <a href="#core.rules" class="smpl">DQUOTE</a> *(<a href="#rule.quoted-string" class="smpl">qdtext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> ) <a href="#core.rules" class="smpl">DQUOTE</a>
     759      <div id="rfc.figure.u.7"></div><pre class="inline"><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span>  <a href="#rule.quoted-string" class="smpl">quoted-string</a>  = <a href="#core.rules" class="smpl">DQUOTE</a> *(<a href="#rule.quoted-string" class="smpl">qdtext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> ) <a href="#core.rules" class="smpl">DQUOTE</a>
    820760  <a href="#rule.quoted-string" class="smpl">qdtext</a>         = &lt;any <a href="#rule.TEXT" class="smpl">TEXT</a> excluding <a href="#core.rules" class="smpl">DQUOTE</a> and "\"&gt;
    821761</pre><div id="rule.quoted-pair">
    822          <p id="rfc.section.2.2.p.19">    The backslash character ("\") <em class="bcp14">MAY</em> be used as a single-character quoting mechanism only within quoted-string and comment constructs.
     762         <p id="rfc.section.1.2.2.p.19">    The backslash character ("\") <em class="bcp14">MAY</em> be used as a single-character quoting mechanism only within quoted-string and comment constructs.
    823763         </p>
    824764      </div>
    825       <div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span>  <a href="#rule.quoted-pair" class="smpl">quoted-text</a>    = %x01-09 /
     765      <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span>  <a href="#rule.quoted-pair" class="smpl">quoted-text</a>    = %x01-09 /
    826766                   %x0B-0C /
    827767                   %x0E-FF ; Characters excluding NUL, <a href="#core.rules" class="smpl">CR</a> and <a href="#core.rules" class="smpl">LF</a>
    828768  <a href="#rule.quoted-pair" class="smpl">quoted-pair</a>    = "\" <a href="#rule.quoted-pair" class="smpl">quoted-text</a>
    829 </pre><h2 id="rfc.section.2.3"><a href="#rfc.section.2.3">2.3</a>&nbsp;<a id="abnf.dependencies" href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></h2>
    830       <p id="rfc.section.2.3.p.1">The ABNF rules below are defined in other parts:</p>
    831       <div id="rfc.figure.u.12"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">request-header</a>  = &lt;request-header, defined in <a href="#Part2" id="rfc.xref.Part2.1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a>&gt;
     769</pre><h3 id="rfc.section.1.2.3"><a href="#rfc.section.1.2.3">1.2.3</a>&nbsp;<a id="abnf.dependencies" href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></h3>
     770      <p id="rfc.section.1.2.3.p.1">The ABNF rules below are defined in other parts:</p>
     771      <div id="rfc.figure.u.9"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">request-header</a>  = &lt;request-header, defined in <a href="#Part2" id="rfc.xref.Part2.1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a>&gt;
    832772  <a href="#abnf.dependencies" class="smpl">response-header</a> = &lt;response-header, defined in <a href="#Part2" id="rfc.xref.Part2.2"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#response.header.fields" title="Response Header Fields">Section 6</a>&gt;
    833 </pre><div id="rfc.figure.u.13"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">accept-params</a>   = &lt;accept-params, defined in <a href="#Part3" id="rfc.xref.Part3.4"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#header.accept" title="Accept">Section 6.1</a>&gt;
    834   <a href="#abnf.dependencies" class="smpl">entity-body</a>     = &lt;entity-body, defined in <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.body" title="Entity Body">Section 4.2</a>&gt;
    835   <a href="#abnf.dependencies" class="smpl">entity-header</a>   = &lt;entity-header, defined in <a href="#Part3" id="rfc.xref.Part3.6"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>&gt;
    836 </pre><div id="rfc.figure.u.14"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">Cache-Control</a>   = &lt;Cache-Control, defined in <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>&gt;
    837   <a href="#abnf.dependencies" class="smpl">Pragma</a>          = &lt;Pragma, defined in <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>&gt;
    838   <a href="#abnf.dependencies" class="smpl">Warning</a>         = &lt;Warning, defined in <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.warning" title="Warning">Section 16.6</a>&gt;
    839 </pre><h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a>&nbsp;<a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h1>
    840       <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a>&nbsp;<a id="http.version" href="#http.version">HTTP Version</a></h2>
    841       <p id="rfc.section.3.1.p.1">HTTP uses a "&lt;major&gt;.&lt;minor&gt;" numbering scheme to indicate versions of the protocol. The protocol versioning policy is intended
     773</pre><div id="rfc.figure.u.10"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">accept-params</a>   = &lt;accept-params, defined in <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#header.accept" title="Accept">Section 6.1</a>&gt;
     774  <a href="#abnf.dependencies" class="smpl">entity-body</a>     = &lt;entity-body, defined in <a href="#Part3" id="rfc.xref.Part3.4"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.body" title="Entity Body">Section 4.2</a>&gt;
     775  <a href="#abnf.dependencies" class="smpl">entity-header</a>   = &lt;entity-header, defined in <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>&gt;
     776</pre><div id="rfc.figure.u.11"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">Cache-Control</a>   = &lt;Cache-Control, defined in <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>&gt;
     777  <a href="#abnf.dependencies" class="smpl">Pragma</a>          = &lt;Pragma, defined in <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>&gt;
     778  <a href="#abnf.dependencies" class="smpl">Warning</a>         = &lt;Warning, defined in <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.warning" title="Warning">Section 16.6</a>&gt;
     779</pre><h2 id="rfc.section.1.3"><a href="#rfc.section.1.3">1.3</a>&nbsp;<a id="intro.overall.operation" href="#intro.overall.operation">Overall Operation</a></h2>
     780      <p id="rfc.section.1.3.p.1">HTTP is a request/response protocol. A client sends a request to the server in the form of a request method, URI, and protocol
     781         version, followed by a MIME-like message containing request modifiers, client information, and possible body content over
     782         a connection with a server. The server responds with a status line, including the message's protocol version and a success
     783         or error code, followed by a MIME-like message containing server information, entity metainformation, and possible entity-body
     784         content. The relationship between HTTP and MIME is described in <a href="p3-payload.html#differences.between.http.entities.and.rfc.2045.entities" title="Differences Between HTTP Entities and RFC 2045 Entities">Appendix A</a> of <a href="#Part3" id="rfc.xref.Part3.6"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.
     785      </p>
     786      <p id="rfc.section.1.3.p.2">Most HTTP communication is initiated by a user agent and consists of a request to be applied to a resource on some origin
     787         server. In the simplest case, this may be accomplished via a single connection (v) between the user agent (UA) and the origin
     788         server (O).
     789      </p>
     790      <div id="rfc.figure.u.12"></div><pre class="drawing">       request chain ------------------------&gt;
     791    UA -------------------v------------------- O
     792       &lt;----------------------- response chain
     793</pre><p id="rfc.section.1.3.p.4">A more complicated situation occurs when one or more intermediaries are present in the request/response chain. There are three
     794         common forms of intermediary: proxy, gateway, and tunnel. A proxy is a forwarding agent, receiving requests for a URI in its
     795         absolute form, rewriting all or part of the message, and forwarding the reformatted request toward the server identified by
     796         the URI. A gateway is a receiving agent, acting as a layer above some other server(s) and, if necessary, translating the requests
     797         to the underlying server's protocol. A tunnel acts as a relay point between two connections without changing the messages;
     798         tunnels are used when the communication needs to pass through an intermediary (such as a firewall) even when the intermediary
     799         cannot understand the contents of the messages.
     800      </p>
     801      <div id="rfc.figure.u.13"></div><pre class="drawing">       request chain --------------------------------------&gt;
     802    UA -----v----- A -----v----- B -----v----- C -----v----- O
     803       &lt;------------------------------------- response chain
     804</pre><p id="rfc.section.1.3.p.6">The figure above shows three intermediaries (A, B, and C) between the user agent and origin server. A request or response
     805         message that travels the whole chain will pass through four separate connections. This distinction is important because some
     806         HTTP communication options may apply only to the connection with the nearest, non-tunnel neighbor, only to the end-points
     807         of the chain, or to all connections along the chain. Although the diagram is linear, each participant may be engaged in multiple,
     808         simultaneous communications. For example, B may be receiving requests from many clients other than A, and/or forwarding requests
     809         to servers other than C, at the same time that it is handling A's request.
     810      </p>
     811      <p id="rfc.section.1.3.p.7">Any party to the communication which is not acting as a tunnel may employ an internal cache for handling requests. The effect
     812         of a cache is that the request/response chain is shortened if one of the participants along the chain has a cached response
     813         applicable to that request. The following illustrates the resulting chain if B has a cached copy of an earlier response from
     814         O (via C) for a request which has not been cached by UA or A.
     815      </p>
     816      <div id="rfc.figure.u.14"></div><pre class="drawing">          request chain ----------&gt;
     817       UA -----v----- A -----v----- B - - - - - - C - - - - - - O
     818          &lt;--------- response chain
     819</pre><p id="rfc.section.1.3.p.9">Not all responses are usefully cacheable, and some requests may contain modifiers which place special requirements on cache
     820         behavior. HTTP requirements for cache behavior and cacheable responses are defined in <a href="p6-cache.html#caching" title="Introduction">Section 1</a> of <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>.
     821      </p>
     822      <p id="rfc.section.1.3.p.10">In fact, there are a wide variety of architectures and configurations of caches and proxies currently being experimented with
     823         or deployed across the World Wide Web. These systems include national hierarchies of proxy caches to save transoceanic bandwidth,
     824         systems that broadcast or multicast cache entries, organizations that distribute subsets of cached data via CD-ROM, and so
     825         on. HTTP systems are used in corporate intranets over high-bandwidth links, and for access via PDAs with low-power radio links
     826         and intermittent connectivity. The goal of HTTP/1.1 is to support the wide diversity of configurations already deployed while
     827         introducing protocol constructs that meet the needs of those who build web applications that require high reliability and,
     828         failing that, at least reliable indications of failure.
     829      </p>
     830      <p id="rfc.section.1.3.p.11">HTTP communication usually takes place over TCP/IP connections. The default port is TCP 80 (&lt;<a href="http://www.iana.org/assignments/port-numbers">http://www.iana.org/assignments/port-numbers</a>&gt;), but other ports can be used. This does not preclude HTTP from being implemented on top of any other protocol on the Internet,
     831         or on other networks. HTTP only presumes a reliable transport; any protocol that provides such guarantees can be used; the
     832         mapping of the HTTP/1.1 request and response structures onto the transport data units of the protocol in question is outside
     833         the scope of this specification.
     834      </p>
     835      <p id="rfc.section.1.3.p.12">In HTTP/1.0, most implementations used a new connection for each request/response exchange. In HTTP/1.1, a connection may
     836         be used for one or more request/response exchanges, although connections may be closed for a variety of reasons (see <a href="#persistent.connections" title="Persistent Connections">Section&nbsp;6.1</a>).
     837      </p>
     838      <h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h1>
     839      <h2 id="rfc.section.2.1"><a href="#rfc.section.2.1">2.1</a>&nbsp;<a id="http.version" href="#http.version">HTTP Version</a></h2>
     840      <p id="rfc.section.2.1.p.1">HTTP uses a "&lt;major&gt;.&lt;minor&gt;" numbering scheme to indicate versions of the protocol. The protocol versioning policy is intended
    842841         to allow the sender to indicate the format of a message and its capacity for understanding further HTTP communication, rather
    843842         than the features obtained via that communication. No change is made to the version number for the addition of message components
     
    847846         of a message within the protocol is changed. See <a href="#RFC2145" id="rfc.xref.RFC2145.1"><cite title="Use and Interpretation of HTTP Version Numbers">[RFC2145]</cite></a> for a fuller explanation.
    848847      </p>
    849       <p id="rfc.section.3.1.p.2">The version of an HTTP message is indicated by an HTTP-Version field in the first line of the message. HTTP-Version is case-sensitive.</p>
     848      <p id="rfc.section.2.1.p.2">The version of an HTTP message is indicated by an HTTP-Version field in the first line of the message. HTTP-Version is case-sensitive.</p>
    850849      <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span>  <a href="#http.version" class="smpl">HTTP-Version</a>   = <a href="#http.version" class="smpl">HTTP-Prot-Name</a> "/" 1*<a href="#core.rules" class="smpl">DIGIT</a> "." 1*<a href="#core.rules" class="smpl">DIGIT</a>
    851850  <a href="#http.version" class="smpl">HTTP-Prot-Name</a> = %x48.54.54.50 ; "HTTP", case-sensitive
    852 </pre><p id="rfc.section.3.1.p.4">Note that the major and minor numbers <em class="bcp14">MUST</em> be treated as separate integers and that each <em class="bcp14">MAY</em> be incremented higher than a single digit. Thus, HTTP/2.4 is a lower version than HTTP/2.13, which in turn is lower than HTTP/12.3.
     851</pre><p id="rfc.section.2.1.p.4">Note that the major and minor numbers <em class="bcp14">MUST</em> be treated as separate integers and that each <em class="bcp14">MAY</em> be incremented higher than a single digit. Thus, HTTP/2.4 is a lower version than HTTP/2.13, which in turn is lower than HTTP/12.3.
    853852         Leading zeros <em class="bcp14">MUST</em> be ignored by recipients and <em class="bcp14">MUST NOT</em> be sent.
    854853      </p>
    855       <p id="rfc.section.3.1.p.5">An application that sends a request or response message that includes HTTP-Version of "HTTP/1.1" <em class="bcp14">MUST</em> be at least conditionally compliant with this specification. Applications that are at least conditionally compliant with this
     854      <p id="rfc.section.2.1.p.5">An application that sends a request or response message that includes HTTP-Version of "HTTP/1.1" <em class="bcp14">MUST</em> be at least conditionally compliant with this specification. Applications that are at least conditionally compliant with this
    856855         specification <em class="bcp14">SHOULD</em> use an HTTP-Version of "HTTP/1.1" in their messages, and <em class="bcp14">MUST</em> do so for any message that is not compatible with HTTP/1.0. For more details on when to send specific HTTP-Version values,
    857856         see <a href="#RFC2145" id="rfc.xref.RFC2145.2"><cite title="Use and Interpretation of HTTP Version Numbers">[RFC2145]</cite></a>.
    858857      </p>
    859       <p id="rfc.section.3.1.p.6">The HTTP version of an application is the highest HTTP version for which the application is at least conditionally compliant.</p>
    860       <p id="rfc.section.3.1.p.7">Proxy and gateway applications need to be careful when forwarding messages in protocol versions different from that of the
     858      <p id="rfc.section.2.1.p.6">The HTTP version of an application is the highest HTTP version for which the application is at least conditionally compliant.</p>
     859      <p id="rfc.section.2.1.p.7">Proxy and gateway applications need to be careful when forwarding messages in protocol versions different from that of the
    861860         application. Since the protocol version indicates the protocol capability of the sender, a proxy/gateway <em class="bcp14">MUST NOT</em> send a message with a version indicator which is greater than its actual version. If a higher version request is received,
    862861         the proxy/gateway <em class="bcp14">MUST</em> either downgrade the request version, or respond with an error, or switch to tunnel behavior.
    863862      </p>
    864       <p id="rfc.section.3.1.p.8">Due to interoperability problems with HTTP/1.0 proxies discovered since the publication of <a href="#RFC2068" id="rfc.xref.RFC2068.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, caching proxies <em class="bcp14">MUST</em>, gateways <em class="bcp14">MAY</em>, and tunnels <em class="bcp14">MUST NOT</em> upgrade the request to the highest version they support. The proxy/gateway's response to that request <em class="bcp14">MUST</em> be in the same major version as the request.
    865       </p>
    866       <p id="rfc.section.3.1.p.9"> </p>
     863      <p id="rfc.section.2.1.p.8">Due to interoperability problems with HTTP/1.0 proxies discovered since the publication of <a href="#RFC2068" id="rfc.xref.RFC2068.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, caching proxies <em class="bcp14">MUST</em>, gateways <em class="bcp14">MAY</em>, and tunnels <em class="bcp14">MUST NOT</em> upgrade the request to the highest version they support. The proxy/gateway's response to that request <em class="bcp14">MUST</em> be in the same major version as the request.
     864      </p>
     865      <p id="rfc.section.2.1.p.9"> </p>
    867866      <dl class="empty">
    868867         <dd> <b>Note:</b> Converting between versions of HTTP may involve modification of header fields required or forbidden by the versions involved.
    869868         </dd>
    870869      </dl>
    871       <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a>&nbsp;<a id="uri" href="#uri">Uniform Resource Identifiers</a></h2>
    872       <p id="rfc.section.3.2.p.1">Uniform Resource Identifiers (URIs) <a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a> are used in HTTP to indicate the target of a request and to identify additional resources related to that resource, the request,
     870      <h2 id="rfc.section.2.2"><a href="#rfc.section.2.2">2.2</a>&nbsp;<a id="uri" href="#uri">Uniform Resource Identifiers</a></h2>
     871      <p id="rfc.section.2.2.p.1">Uniform Resource Identifiers (URIs) <a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a> are used in HTTP to indicate the target of a request and to identify additional resources related to that resource, the request,
    873872         or the response. Each protocol element in HTTP that allows a URI reference will indicate in its ABNF whether the element allows
    874873         only a URI in absolute form, any relative reference, or some limited subset of the URI-reference grammar. Unless otherwise
    875874         indicated, relative URI references are to be parsed relative to the URI corresponding to the request target (the base URI).
    876875      </p>
    877       <p id="rfc.section.3.2.p.2">This specification adopts the definitions of "URI-reference", "absolute-URI", "fragment", "port", "host", "path-abempty",
     876      <p id="rfc.section.2.2.p.2">This specification adopts the definitions of "URI-reference", "absolute-URI", "fragment", "port", "host", "path-abempty",
    878877         "path-absolute", "query", and "authority" from <a href="#RFC3986" id="rfc.xref.RFC3986.3"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>:
    879878      </p>
     
    889888  <a href="#uri" class="smpl">relative-part</a> = &lt;relative-part, defined in <a href="#RFC3986" id="rfc.xref.RFC3986.12"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>&gt;
    890889  <a href="#uri" class="smpl">relativeURI</a>   = <a href="#uri" class="smpl">relative-part</a> [ "?" <a href="#uri" class="smpl">query</a> ]
    891 </pre><p id="rfc.section.3.2.p.4">HTTP does not place an a priori limit on the length of a URI. Servers <em class="bcp14">MUST</em> be able to handle the URI of any resource they serve, and <em class="bcp14">SHOULD</em> be able to handle URIs of unbounded length if they provide GET-based forms that could generate such URIs. A server <em class="bcp14">SHOULD</em> return 414 (Request-URI Too Long) status if a URI is longer than the server can handle (see <a href="p2-semantics.html#status.414" title="414 Request-URI Too Long">Section 9.4.15</a> of <a href="#Part2" id="rfc.xref.Part2.3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).
    892       </p>
    893       <p id="rfc.section.3.2.p.5"> </p>
     890</pre><p id="rfc.section.2.2.p.4">HTTP does not place an a priori limit on the length of a URI. Servers <em class="bcp14">MUST</em> be able to handle the URI of any resource they serve, and <em class="bcp14">SHOULD</em> be able to handle URIs of unbounded length if they provide GET-based forms that could generate such URIs. A server <em class="bcp14">SHOULD</em> return 414 (Request-URI Too Long) status if a URI is longer than the server can handle (see <a href="p2-semantics.html#status.414" title="414 Request-URI Too Long">Section 9.4.15</a> of <a href="#Part2" id="rfc.xref.Part2.3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).
     891      </p>
     892      <p id="rfc.section.2.2.p.5"> </p>
    894893      <dl class="empty">
    895894         <dd> <b>Note:</b> Servers ought to be cautious about depending on URI lengths above 255 bytes, because some older client or proxy implementations
     
    897896         </dd>
    898897      </dl>
    899       <h3 id="rfc.section.3.2.1"><a href="#rfc.section.3.2.1">3.2.1</a>&nbsp;<a id="http.uri" href="#http.uri">http URI scheme</a></h3>
     898      <h3 id="rfc.section.2.2.1"><a href="#rfc.section.2.2.1">2.2.1</a>&nbsp;<a id="http.uri" href="#http.uri">http URI scheme</a></h3>
    900899      <div id="rfc.iref.h.1"></div>
    901900      <div id="rfc.iref.u.1"></div>
    902       <p id="rfc.section.3.2.1.p.1">The "http" scheme is used to locate network resources via the HTTP protocol. This section defines the syntax and semantics
     901      <p id="rfc.section.2.2.1.p.1">The "http" scheme is used to locate network resources via the HTTP protocol. This section defines the syntax and semantics
    903902         for identifiers using the http or https URI schemes.
    904903      </p>
    905904      <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.24"></span>  <a href="#http.uri" class="smpl">http-URI</a> = "http:" "//" <a href="#uri" class="smpl">authority</a> <a href="#uri" class="smpl">path-abempty</a> [ "?" <a href="#uri" class="smpl">query</a> ]
    906 </pre><p id="rfc.section.3.2.1.p.3">If the port is empty or not given, port 80 is assumed. The semantics are that the identified resource is located at the server
    907          listening for TCP connections on that port of that host, and the Request-URI for the resource is path-absolute (<a href="#request-uri" title="Request-URI">Section&nbsp;5.1.2</a>). The use of IP addresses in URLs <em class="bcp14">SHOULD</em> be avoided whenever possible (see <a href="#RFC1900" id="rfc.xref.RFC1900.1"><cite title="Renumbering Needs Work">[RFC1900]</cite></a>). If the path-absolute is not present in the URL, it <em class="bcp14">MUST</em> be given as "/" when used as a Request-URI for a resource (<a href="#request-uri" title="Request-URI">Section&nbsp;5.1.2</a>). If a proxy receives a host name which is not a fully qualified domain name, it <em class="bcp14">MAY</em> add its domain to the host name it received. If a proxy receives a fully qualified domain name, the proxy <em class="bcp14">MUST NOT</em> change the host name.
     905</pre><p id="rfc.section.2.2.1.p.3">If the port is empty or not given, port 80 is assumed. The semantics are that the identified resource is located at the server
     906         listening for TCP connections on that port of that host, and the Request-URI for the resource is path-absolute (<a href="#request-uri" title="Request-URI">Section&nbsp;4.1.2</a>). The use of IP addresses in URLs <em class="bcp14">SHOULD</em> be avoided whenever possible (see <a href="#RFC1900" id="rfc.xref.RFC1900.1"><cite title="Renumbering Needs Work">[RFC1900]</cite></a>). If the path-absolute is not present in the URL, it <em class="bcp14">MUST</em> be given as "/" when used as a Request-URI for a resource (<a href="#request-uri" title="Request-URI">Section&nbsp;4.1.2</a>). If a proxy receives a host name which is not a fully qualified domain name, it <em class="bcp14">MAY</em> add its domain to the host name it received. If a proxy receives a fully qualified domain name, the proxy <em class="bcp14">MUST NOT</em> change the host name.
    908907      </p>
    909908      <dl class="empty">
     
    911910         </dd>
    912911      </dl>
    913       <h3 id="rfc.section.3.2.2"><a href="#rfc.section.3.2.2">3.2.2</a>&nbsp;<a id="uri.comparison" href="#uri.comparison">URI Comparison</a></h3>
    914       <p id="rfc.section.3.2.2.p.1">When comparing two URIs to decide if they match or not, a client <em class="bcp14">SHOULD</em> use a case-sensitive octet-by-octet comparison of the entire URIs, with these exceptions:
     912      <h3 id="rfc.section.2.2.2"><a href="#rfc.section.2.2.2">2.2.2</a>&nbsp;<a id="uri.comparison" href="#uri.comparison">URI Comparison</a></h3>
     913      <p id="rfc.section.2.2.2.p.1">When comparing two URIs to decide if they match or not, a client <em class="bcp14">SHOULD</em> use a case-sensitive octet-by-octet comparison of the entire URIs, with these exceptions:
    915914      </p>
    916915      <ul>
     
    922921         <li>An empty path-absolute is equivalent to an path-absolute of "/".</li>
    923922      </ul>
    924       <p id="rfc.section.3.2.2.p.2">Characters other than those in the "reserved" set (see <a href="#RFC3986" id="rfc.xref.RFC3986.13"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.2">Section 2.2</a>) are equivalent to their ""%" <a href="#core.rules" class="smpl">HEXDIG</a>  <a href="#core.rules" class="smpl">HEXDIG</a>" encoding.
    925       </p>
    926       <p id="rfc.section.3.2.2.p.3">For example, the following three URIs are equivalent:</p>
     923      <p id="rfc.section.2.2.2.p.2">Characters other than those in the "reserved" set (see <a href="#RFC3986" id="rfc.xref.RFC3986.13"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.2">Section 2.2</a>) are equivalent to their ""%" <a href="#core.rules" class="smpl">HEXDIG</a>  <a href="#core.rules" class="smpl">HEXDIG</a>" encoding.
     924      </p>
     925      <p id="rfc.section.2.2.2.p.3">For example, the following three URIs are equivalent:</p>
    927926      <div id="rfc.figure.u.18"></div><pre class="text">   http://example.com:80/~smith/home.html
    928927   http://EXAMPLE.com/%7Esmith/home.html
    929928   http://EXAMPLE.com:/%7esmith/home.html
    930 </pre><h2 id="rfc.section.3.3"><a href="#rfc.section.3.3">3.3</a>&nbsp;<a id="date.time.formats" href="#date.time.formats">Date/Time Formats</a></h2>
    931       <h3 id="rfc.section.3.3.1"><a href="#rfc.section.3.3.1">3.3.1</a>&nbsp;<a id="full.date" href="#full.date">Full Date</a></h3>
    932       <p id="rfc.section.3.3.1.p.1">HTTP applications have historically allowed three different formats for the representation of date/time stamps:</p>
     929</pre><h2 id="rfc.section.2.3"><a href="#rfc.section.2.3">2.3</a>&nbsp;<a id="date.time.formats" href="#date.time.formats">Date/Time Formats</a></h2>
     930      <h3 id="rfc.section.2.3.1"><a href="#rfc.section.2.3.1">2.3.1</a>&nbsp;<a id="full.date" href="#full.date">Full Date</a></h3>
     931      <p id="rfc.section.2.3.1.p.1">HTTP applications have historically allowed three different formats for the representation of date/time stamps:</p>
    933932      <div id="rfc.figure.u.19"></div><pre class="text">   Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
    934933   Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
    935934   Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
    936 </pre><p id="rfc.section.3.3.1.p.3">The first format is preferred as an Internet standard and represents 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>. The other formats are described here only for compatibility with obsolete implementations. HTTP/1.1 clients and servers
     935</pre><p id="rfc.section.2.3.1.p.3">The first format is preferred as an Internet standard and represents 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>. The other formats are described here only for compatibility with obsolete implementations. HTTP/1.1 clients and servers
    937936         that parse the 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. See <a href="#tolerant.applications" title="Tolerant Applications">Appendix&nbsp;A</a> for further information.
    938937      </p>
     
    942941         </dd>
    943942      </dl>
    944       <p id="rfc.section.3.3.1.p.5">All HTTP date/time stamps <em class="bcp14">MUST</em> be represented in Greenwich Mean Time (GMT), without exception. For the purposes of HTTP, GMT is exactly equal to UTC (Coordinated
     943      <p id="rfc.section.2.3.1.p.5">All HTTP date/time stamps <em class="bcp14">MUST</em> be represented in Greenwich Mean Time (GMT), without exception. For the purposes of HTTP, GMT is exactly equal to UTC (Coordinated
    945944         Universal Time). This is indicated in the first two formats by the inclusion of "GMT" as the three-letter abbreviation for
    946945         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 LWS beyond that specifically included as SP in the grammar.
     
    997996  s-Nov = %x4E.6F.76 ; "Nov", case-sensitive
    998997  s-Dec = %x44.65.63 ; "Dec", case-sensitive
    999 </pre><p id="rfc.section.3.3.1.p.7"> <b>Note:</b> HTTP requirements for the date/time stamp format apply only to their usage within the protocol stream. Clients and servers
     998</pre><p id="rfc.section.2.3.1.p.7"> <b>Note:</b> HTTP requirements for the date/time stamp format apply only to their usage within the protocol stream. Clients and servers
    1000999         are not required to use these formats for user presentation, request logging, etc.
    10011000      </p>
    1002       <h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a>&nbsp;<a id="transfer.codings" href="#transfer.codings">Transfer Codings</a></h2>
    1003       <p id="rfc.section.3.4.p.1">Transfer-coding values are used to indicate an encoding transformation that has been, can be, or may need to be applied to
     1001      <h2 id="rfc.section.2.4"><a href="#rfc.section.2.4">2.4</a>&nbsp;<a id="transfer.codings" href="#transfer.codings">Transfer Codings</a></h2>
     1002      <p id="rfc.section.2.4.p.1">Transfer-coding values are used to indicate an encoding transformation that has been, can be, or may need to be applied to
    10041003         an entity-body in order to ensure "safe transport" through the network. This differs from a content coding in that the transfer-coding
    10051004         is a property of the message, not of the original entity.
     
    10081007  <a href="#transfer.codings" class="smpl">transfer-extension</a>      = <a href="#rule.token.separators" class="smpl">token</a> *( <a href="#rule.whitespace" class="smpl">OWS</a> ";" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#transfer.codings" class="smpl">parameter</a> )
    10091008</pre><div id="rule.parameter">
    1010          <p id="rfc.section.3.4.p.3">      Parameters are in the form of attribute/value pairs.</p>
     1009         <p id="rfc.section.2.4.p.3">      Parameters are in the form of attribute/value pairs.</p>
    10111010      </div>
    10121011      <div id="rfc.figure.u.22"></div><pre class="inline"><span id="rfc.iref.g.39"></span><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span>  <a href="#transfer.codings" class="smpl">parameter</a>               = <a href="#rule.parameter" class="smpl">attribute</a> <a href="#rule.whitespace" class="smpl">BWS</a> "=" <a href="#rule.whitespace" class="smpl">BWS</a> <a href="#rule.parameter" class="smpl">value</a>
    10131012  <a href="#rule.parameter" class="smpl">attribute</a>               = <a href="#rule.token.separators" class="smpl">token</a>
    10141013  <a href="#rule.parameter" class="smpl">value</a>                   = <a href="#rule.token.separators" class="smpl">token</a> / <a href="#rule.quoted-string" class="smpl">quoted-string</a>
    1015 </pre><p id="rfc.section.3.4.p.5">All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in the TE header field (<a href="#header.te" id="rfc.xref.header.te.1" title="TE">Section&nbsp;8.5</a>) and in the Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.1" title="Transfer-Encoding">Section&nbsp;8.7</a>).
    1016       </p>
    1017       <p id="rfc.section.3.4.p.6">Whenever a transfer-coding is applied to a message-body, the set of transfer-codings <em class="bcp14">MUST</em> include "chunked", unless the message indicates it is terminated by closing the connection. When the "chunked" transfer-coding
     1014</pre><p id="rfc.section.2.4.p.5">All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in the TE header field (<a href="#header.te" id="rfc.xref.header.te.1" title="TE">Section&nbsp;7.5</a>) and in the Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.1" title="Transfer-Encoding">Section&nbsp;7.7</a>).
     1015      </p>
     1016      <p id="rfc.section.2.4.p.6">Whenever a transfer-coding is applied to a message-body, the set of transfer-codings <em class="bcp14">MUST</em> include "chunked", unless the message indicates it is terminated by closing the connection. When the "chunked" transfer-coding
    10181017         is used, it <em class="bcp14">MUST</em> be the last transfer-coding applied to the message-body. The "chunked" transfer-coding <em class="bcp14">MUST NOT</em> be applied more than once to a message-body. These rules allow the recipient to determine the transfer-length of the message
    1019          (<a href="#message.length" title="Message Length">Section&nbsp;4.4</a>).
    1020       </p>
    1021       <p id="rfc.section.3.4.p.7">Transfer-codings are analogous to the Content-Transfer-Encoding values of MIME <a href="#RFC2045" id="rfc.xref.RFC2045.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>, which were designed to enable safe transport of binary data over a 7-bit transport service. However, safe transport has
     1018         (<a href="#message.length" title="Message Length">Section&nbsp;3.4</a>).
     1019      </p>
     1020      <p id="rfc.section.2.4.p.7">Transfer-codings are analogous to the Content-Transfer-Encoding values of MIME <a href="#RFC2045" id="rfc.xref.RFC2045.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>, which were designed to enable safe transport of binary data over a 7-bit transport service. However, safe transport has
    10221021         a different focus for an 8bit-clean transfer protocol. In HTTP, the only unsafe characteristic of message-bodies is the difficulty
    1023          in determining the exact body length (<a href="#message.length" title="Message Length">Section&nbsp;4.4</a>), or the desire to encrypt data over a shared transport.
    1024       </p>
    1025       <p id="rfc.section.3.4.p.8">The Internet Assigned Numbers Authority (IANA) acts as a registry for transfer-coding value tokens. Initially, the registry
    1026          contains the following tokens: "chunked" (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;3.4.1</a>), "gzip", "compress", and "deflate" (<a href="p3-payload.html#content.codings" title="Content Codings">Section 3.2</a> of <a href="#Part3" id="rfc.xref.Part3.7"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>).
    1027       </p>
    1028       <p id="rfc.section.3.4.p.9">New transfer-coding value tokens <em class="bcp14">SHOULD</em> be registered in the same way as new content-coding value tokens (<a href="p3-payload.html#content.codings" title="Content Codings">Section 3.2</a> of <a href="#Part3" id="rfc.xref.Part3.8"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>).
    1029       </p>
    1030       <p id="rfc.section.3.4.p.10">A server which receives an entity-body with a transfer-coding it does not understand <em class="bcp14">SHOULD</em> return 501 (Not Implemented), and close the connection. A server <em class="bcp14">MUST NOT</em> send transfer-codings to an HTTP/1.0 client.
    1031       </p>
    1032       <h3 id="rfc.section.3.4.1"><a href="#rfc.section.3.4.1">3.4.1</a>&nbsp;<a id="chunked.transfer.encoding" href="#chunked.transfer.encoding">Chunked Transfer Coding</a></h3>
    1033       <p id="rfc.section.3.4.1.p.1">The chunked encoding modifies the body of a message in order to transfer it as a series of chunks, each with its own size
     1022         in determining the exact body length (<a href="#message.length" title="Message Length">Section&nbsp;3.4</a>), or the desire to encrypt data over a shared transport.
     1023      </p>
     1024      <p id="rfc.section.2.4.p.8">The Internet Assigned Numbers Authority (IANA) acts as a registry for transfer-coding value tokens. Initially, the registry
     1025         contains the following tokens: "chunked" (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;2.4.1</a>), "gzip", "compress", and "deflate" (<a href="p3-payload.html#content.codings" title="Content Codings">Section 3.2</a> of <a href="#Part3" id="rfc.xref.Part3.7"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>).
     1026      </p>
     1027      <p id="rfc.section.2.4.p.9">New transfer-coding value tokens <em class="bcp14">SHOULD</em> be registered in the same way as new content-coding value tokens (<a href="p3-payload.html#content.codings" title="Content Codings">Section 3.2</a> of <a href="#Part3" id="rfc.xref.Part3.8"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>).
     1028      </p>
     1029      <p id="rfc.section.2.4.p.10">A server which receives an entity-body with a transfer-coding it does not understand <em class="bcp14">SHOULD</em> return 501 (Not Implemented), and close the connection. A server <em class="bcp14">MUST NOT</em> send transfer-codings to an HTTP/1.0 client.
     1030      </p>
     1031      <h3 id="rfc.section.2.4.1"><a href="#rfc.section.2.4.1">2.4.1</a>&nbsp;<a id="chunked.transfer.encoding" href="#chunked.transfer.encoding">Chunked Transfer Coding</a></h3>
     1032      <p id="rfc.section.2.4.1.p.1">The chunked encoding modifies the body of a message in order to transfer it as a series of chunks, each with its own size
    10341033         indicator, followed by an <em class="bcp14">OPTIONAL</em> trailer containing entity-header fields. This allows dynamically produced content to be transferred along with the information
    10351034         necessary for the recipient to verify that it has received the full message.
     
    10511050  <a href="#chunked.transfer.encoding" class="smpl">chunk-data</a>     = 1*<a href="#core.rules" class="smpl">OCTET</a> ; a sequence of chunk-size octets
    10521051  <a href="#chunked.transfer.encoding" class="smpl">trailer-part</a>   = *(<a href="#abnf.dependencies" class="smpl">entity-header</a> <a href="#core.rules" class="smpl">CRLF</a>)
    1053 </pre><p id="rfc.section.3.4.1.p.3">The chunk-size field is a string of hex digits indicating the size of the chunk-data in octets. The chunked encoding is ended
     1052</pre><p id="rfc.section.2.4.1.p.3">The chunk-size field is a string of hex digits indicating the size of the chunk-data in octets. The chunked encoding is ended
    10541053         by any chunk whose size is zero, followed by the trailer, which is terminated by an empty line.
    10551054      </p>
    1056       <p id="rfc.section.3.4.1.p.4">The trailer allows the sender to include additional HTTP header fields at the end of the message. The Trailer header field
    1057          can be used to indicate which header fields are included in a trailer (see <a href="#header.trailer" id="rfc.xref.header.trailer.1" title="Trailer">Section&nbsp;8.6</a>).
    1058       </p>
    1059       <p id="rfc.section.3.4.1.p.5">A server using chunked transfer-coding in a response <em class="bcp14">MUST NOT</em> use the trailer for any header fields unless at least one of the following is true:
     1055      <p id="rfc.section.2.4.1.p.4">The trailer allows the sender to include additional HTTP header fields at the end of the message. The Trailer header field
     1056         can be used to indicate which header fields are included in a trailer (see <a href="#header.trailer" id="rfc.xref.header.trailer.1" title="Trailer">Section&nbsp;7.6</a>).
     1057      </p>
     1058      <p id="rfc.section.2.4.1.p.5">A server using chunked transfer-coding in a response <em class="bcp14">MUST NOT</em> use the trailer for any header fields unless at least one of the following is true:
    10601059      </p>
    10611060      <ol>
    10621061         <li>the request included a TE header field that indicates "trailers" is acceptable in the transfer-coding of the response, as
    1063             described in <a href="#header.te" id="rfc.xref.header.te.2" title="TE">Section&nbsp;8.5</a>; or,
     1062            described in <a href="#header.te" id="rfc.xref.header.te.2" title="TE">Section&nbsp;7.5</a>; or,
    10641063         </li>
    10651064         <li>the server is the origin server for the response, the trailer fields consist entirely of optional metadata, and the recipient
     
    10681067         </li>
    10691068      </ol>
    1070       <p id="rfc.section.3.4.1.p.6">This requirement prevents an interoperability failure when the message is being received by an HTTP/1.1 (or later) proxy and
     1069      <p id="rfc.section.2.4.1.p.6">This requirement prevents an interoperability failure when the message is being received by an HTTP/1.1 (or later) proxy and
    10711070         forwarded to an HTTP/1.0 recipient. It avoids a situation where compliance with the protocol would have necessitated a possibly
    10721071         infinite buffer on the proxy.
    10731072      </p>
    1074       <p id="rfc.section.3.4.1.p.7">A process for decoding the "chunked" transfer-coding can be represented in pseudo-code as:</p>
     1073      <p id="rfc.section.2.4.1.p.7">A process for decoding the "chunked" transfer-coding can be represented in pseudo-code as:</p>
    10751074      <div id="rfc.figure.u.24"></div><pre class="text">  length := 0
    10761075  read chunk-size, chunk-ext (if any) and CRLF
     
    10881087  Content-Length := length
    10891088  Remove "chunked" from Transfer-Encoding
    1090 </pre><p id="rfc.section.3.4.1.p.9">All HTTP/1.1 applications <em class="bcp14">MUST</em> be able to receive and decode the "chunked" transfer-coding, and <em class="bcp14">MUST</em> ignore chunk-ext extensions they do not understand.
    1091       </p>
    1092       <h2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a>&nbsp;<a id="product.tokens" href="#product.tokens">Product Tokens</a></h2>
    1093       <p id="rfc.section.3.5.p.1">Product tokens are used to allow communicating applications to identify themselves by software name and version. Most fields
     1089</pre><p id="rfc.section.2.4.1.p.9">All HTTP/1.1 applications <em class="bcp14">MUST</em> be able to receive and decode the "chunked" transfer-coding, and <em class="bcp14">MUST</em> ignore chunk-ext extensions they do not understand.
     1090      </p>
     1091      <h2 id="rfc.section.2.5"><a href="#rfc.section.2.5">2.5</a>&nbsp;<a id="product.tokens" href="#product.tokens">Product Tokens</a></h2>
     1092      <p id="rfc.section.2.5.p.1">Product tokens are used to allow communicating applications to identify themselves by software name and version. Most fields
    10941093         using product tokens also allow sub-products which form a significant part of the application to be listed, separated by white
    10951094         space. By convention, the products are listed in order of their significance for identifying the application.
     
    10971096      <div id="rfc.figure.u.25"></div><pre class="inline"><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span>  <a href="#product.tokens" class="smpl">product</a>         = <a href="#rule.token.separators" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>]
    10981097  <a href="#product.tokens" class="smpl">product-version</a> = <a href="#rule.token.separators" class="smpl">token</a>
    1099 </pre><p id="rfc.section.3.5.p.3">Examples:</p>
     1098</pre><p id="rfc.section.2.5.p.3">Examples:</p>
    11001099      <div id="rfc.figure.u.26"></div><pre class="text">    User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    11011100    Server: Apache/0.8.4
    1102 </pre><p id="rfc.section.3.5.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 character <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).
    1103       </p>
    1104       <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a id="http.message" href="#http.message">HTTP Message</a></h1>
    1105       <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a id="message.types" href="#message.types">Message Types</a></h2>
    1106       <p id="rfc.section.4.1.p.1">HTTP messages consist of requests from client to server and responses from server to client.</p>
     1101</pre><p id="rfc.section.2.5.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 character <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).
     1102      </p>
     1103      <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a>&nbsp;<a id="http.message" href="#http.message">HTTP Message</a></h1>
     1104      <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a>&nbsp;<a id="message.types" href="#message.types">Message Types</a></h2>
     1105      <p id="rfc.section.3.1.p.1">HTTP messages consist of requests from client to server and responses from server to client.</p>
    11071106      <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.53"></span>  <a href="#message.types" class="smpl">HTTP-message</a>   = <a href="#request" class="smpl">Request</a> / <a href="#response" class="smpl">Response</a>     ; HTTP/1.1 messages
    1108 </pre><p id="rfc.section.4.1.p.3">Request (<a href="#request" title="Request">Section&nbsp;5</a>) and Response (<a href="#response" title="Response">Section&nbsp;6</a>) messages use the generic message format of <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a> for transferring entities (the payload of the message). Both types of message consist of a start-line, zero or more header
     1107</pre><p id="rfc.section.3.1.p.3">Request (<a href="#request" title="Request">Section&nbsp;4</a>) and Response (<a href="#response" title="Response">Section&nbsp;5</a>) messages use the generic message format of <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a> for transferring entities (the payload of the message). Both types of message consist of a start-line, zero or more header
    11091108         fields (also known as "headers"), an empty line (i.e., a line with nothing preceding the CRLF) indicating the end of the header
    11101109         fields, and possibly a message-body.
     
    11151114                    [ <a href="#message.body" class="smpl">message-body</a> ]
    11161115  <a href="#message.types" class="smpl">start-line</a>      = <a href="#request-line" class="smpl">Request-Line</a> / <a href="#status-line" class="smpl">Status-Line</a>
    1117 </pre><p id="rfc.section.4.1.p.5">In the interest of robustness, servers <em class="bcp14">SHOULD</em> ignore any empty line(s) received where a Request-Line is expected. In other words, if the server is reading the protocol
     1116</pre><p id="rfc.section.3.1.p.5">In the interest of robustness, servers <em class="bcp14">SHOULD</em> ignore any empty line(s) received where a Request-Line is expected. In other words, if the server is reading the protocol
    11181117         stream at the beginning of a message and receives a CRLF first, it should ignore the CRLF.
    11191118      </p>
    1120       <p id="rfc.section.4.1.p.6">Certain buggy HTTP/1.0 client implementations generate extra CRLF's after a POST request. To restate what is explicitly forbidden
     1119      <p id="rfc.section.3.1.p.6">Certain buggy HTTP/1.0 client implementations generate extra CRLF's after a POST request. To restate what is explicitly forbidden
    11211120         by the BNF, an HTTP/1.1 client <em class="bcp14">MUST NOT</em> preface or follow a request with an extra CRLF.
    11221121      </p>
    1123       <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a>&nbsp;<a id="message.headers" href="#message.headers">Message Headers</a></h2>
    1124       <p id="rfc.section.4.2.p.1">HTTP header fields, which include general-header (<a href="#general.header.fields" title="General Header Fields">Section&nbsp;4.5</a>), request-header (<a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), response-header (<a href="p2-semantics.html#response.header.fields" title="Response Header Fields">Section 6</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), and entity-header (<a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a> of <a href="#Part3" id="rfc.xref.Part3.9"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) fields, follow the same generic format as that given in <a href="http://tools.ietf.org/html/rfc5322#section-2.1">Section 2.1</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>. Each header field consists of a name followed by a colon (":") and the field value. Field names are case-insensitive. The
     1122      <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a>&nbsp;<a id="message.headers" href="#message.headers">Message Headers</a></h2>
     1123      <p id="rfc.section.3.2.p.1">HTTP header fields, which include general-header (<a href="#general.header.fields" title="General Header Fields">Section&nbsp;3.5</a>), request-header (<a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), response-header (<a href="p2-semantics.html#response.header.fields" title="Response Header Fields">Section 6</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), and entity-header (<a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a> of <a href="#Part3" id="rfc.xref.Part3.9"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) fields, follow the same generic format as that given in <a href="http://tools.ietf.org/html/rfc5322#section-2.1">Section 2.1</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>. Each header field consists of a name followed by a colon (":") and the field value. Field names are case-insensitive. The
    11251124         field value <em class="bcp14">MAY</em> be preceded by any amount of LWS, though a single SP is preferred. Header fields can be extended over multiple lines by preceding
    11261125         each extra line with at least one SP or HTAB. Applications ought to follow "common form", where one is known or indicated,
     
    11321131  <a href="#message.headers" class="smpl">field-value</a>    = *( <a href="#message.headers" class="smpl">field-content</a> / <a href="#rule.whitespace" class="smpl">OWS</a> )
    11331132  <a href="#message.headers" class="smpl">field-content</a>  = &lt;field content&gt;
    1134 </pre><p id="rfc.section.4.2.p.3"> <span class="comment">[rfc.comment.1: whitespace between field-name and colon is an error and MUST NOT be accepted]</span>
    1135       </p>
    1136       <p id="rfc.section.4.2.p.4">The field-content does not include any leading or trailing LWS: linear white space occurring before the first non-whitespace
     1133</pre><p id="rfc.section.3.2.p.3"> <span class="comment">[rfc.comment.1: whitespace between field-name and colon is an error and MUST NOT be accepted]</span>
     1134      </p>
     1135      <p id="rfc.section.3.2.p.4">The field-content does not include any leading or trailing LWS: linear white space occurring before the first non-whitespace
    11371136         character of the field-value or after the last non-whitespace character of the field-value. Such leading or trailing LWS <em class="bcp14">MAY</em> be removed without changing the semantics of the field value. Any LWS that occurs between field-content <em class="bcp14">MAY</em> be replaced with a single SP before interpreting the field value or forwarding the message downstream.
    11381137      </p>
    1139       <p id="rfc.section.4.2.p.5">The order in which header fields with differing field names are received is not significant. However, it is "good practice"
     1138      <p id="rfc.section.3.2.p.5">The order in which header fields with differing field names are received is not significant. However, it is "good practice"
    11401139         to send general-header fields first, followed by request-header or response-header fields, and ending with the entity-header
    11411140         fields.
    11421141      </p>
    1143       <p id="rfc.section.4.2.p.6">Multiple message-header fields with the same field-name <em class="bcp14">MAY</em> be present in a message if and only if the entire field-value for that header field is defined as a comma-separated list [i.e.,
     1142      <p id="rfc.section.3.2.p.6">Multiple message-header fields with the same field-name <em class="bcp14">MAY</em> be present in a message if and only if the entire field-value for that header field is defined as a comma-separated list [i.e.,
    11441143         #(values)]. It <em class="bcp14">MUST</em> be possible to combine the multiple header fields into one "field-name: field-value" pair, without changing the semantics
    11451144         of the message, by appending each subsequent field-value to the first, each separated by a comma. The order in which header
     
    11471146         thus a proxy <em class="bcp14">MUST NOT</em> change the order of these field values when a message is forwarded.
    11481147      </p>
    1149       <p id="rfc.section.4.2.p.7"> </p>
     1148      <p id="rfc.section.3.2.p.7"> </p>
    11501149      <dl class="empty">
    11511150         <dd> <b>Note:</b> the "Set-Cookie" header as implemented in practice (as opposed to how it is specified in <a href="#RFC2109" id="rfc.xref.RFC2109.1"><cite title="HTTP State Management Mechanism">[RFC2109]</cite></a>) can occur multiple times, but does not use the list syntax, and thus cannot be combined into a single line. (See Appendix
     
    11531152         </dd>
    11541153      </dl>
    1155       <h2 id="rfc.section.4.3"><a href="#rfc.section.4.3">4.3</a>&nbsp;<a id="message.body" href="#message.body">Message Body</a></h2>
    1156       <p id="rfc.section.4.3.p.1">The message-body (if any) of an HTTP message is used to carry the entity-body associated with the request or response. The
     1154      <h2 id="rfc.section.3.3"><a href="#rfc.section.3.3">3.3</a>&nbsp;<a id="message.body" href="#message.body">Message Body</a></h2>
     1155      <p id="rfc.section.3.3.p.1">The message-body (if any) of an HTTP message is used to carry the entity-body associated with the request or response. The
    11571156         message-body differs from the entity-body only when a transfer-coding has been applied, as indicated by the Transfer-Encoding
    1158          header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.2" title="Transfer-Encoding">Section&nbsp;8.7</a>).
     1157         header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.2" title="Transfer-Encoding">Section&nbsp;7.7</a>).
    11591158      </p>
    11601159      <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.60"></span>  <a href="#message.body" class="smpl">message-body</a> = <a href="#abnf.dependencies" class="smpl">entity-body</a>
    11611160               / &lt;entity-body encoded as per <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a>&gt;
    1162 </pre><p id="rfc.section.4.3.p.3">Transfer-Encoding <em class="bcp14">MUST</em> be used to indicate any transfer-codings applied by an application to ensure safe and proper transfer of the message. Transfer-Encoding
    1163          is a property of the message, not of the entity, and thus <em class="bcp14">MAY</em> be added or removed by any application along the request/response chain. (However, <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.4</a> places restrictions on when certain transfer-codings may be used.)
    1164       </p>
    1165       <p id="rfc.section.4.3.p.4">The rules for when a message-body is allowed in a message differ for requests and responses.</p>
    1166       <p id="rfc.section.4.3.p.5">The presence of a message-body in a request is signaled by the inclusion of a Content-Length or Transfer-Encoding header field
     1161</pre><p id="rfc.section.3.3.p.3">Transfer-Encoding <em class="bcp14">MUST</em> be used to indicate any transfer-codings applied by an application to ensure safe and proper transfer of the message. Transfer-Encoding
     1162         is a property of the message, not of the entity, and thus <em class="bcp14">MAY</em> be added or removed by any application along the request/response chain. (However, <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;2.4</a> places restrictions on when certain transfer-codings may be used.)
     1163      </p>
     1164      <p id="rfc.section.3.3.p.4">The rules for when a message-body is allowed in a message differ for requests and responses.</p>
     1165      <p id="rfc.section.3.3.p.5">The presence of a message-body in a request is signaled by the inclusion of a Content-Length or Transfer-Encoding header field
    11671166         in the request's message-headers. A message-body <em class="bcp14">MUST NOT</em> be included in a request if the specification of the request method (<a href="p2-semantics.html#method" title="Method">Section 3</a> of <a href="#Part2" id="rfc.xref.Part2.6"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) explicitly disallows an entity-body in requests. When a request message contains both a message-body of non-zero length
    11681167         and a method that does not define any semantics for that request message-body, then an origin server <em class="bcp14">SHOULD</em> either ignore the message-body or respond with an appropriate error message (e.g., 413). A proxy or gateway, when presented
    11691168         the same request, <em class="bcp14">SHOULD</em> either forward the request inbound with the message-body or ignore the message-body when determining a response.
    11701169      </p>
    1171       <p id="rfc.section.4.3.p.6">For response messages, whether or not a message-body is included with a message is dependent on both the request method and
    1172          the response status code (<a href="#status.code.and.reason.phrase" title="Status Code and Reason Phrase">Section&nbsp;6.1.1</a>). All responses to the HEAD request method <em class="bcp14">MUST NOT</em> include a message-body, even though the presence of entity-header fields might lead one to believe they do. All 1xx (informational),
     1170      <p id="rfc.section.3.3.p.6">For response messages, whether or not a message-body is included with a message is dependent on both the request method and
     1171         the response status code (<a href="#status.code.and.reason.phrase" title="Status Code and Reason Phrase">Section&nbsp;5.1.1</a>). All responses to the HEAD request method <em class="bcp14">MUST NOT</em> include a message-body, even though the presence of entity-header fields might lead one to believe they do. All 1xx (informational),
    11731172         204 (No Content), and 304 (Not Modified) responses <em class="bcp14">MUST NOT</em> include a message-body. All other responses do include a message-body, although it <em class="bcp14">MAY</em> be of zero length.
    11741173      </p>
    1175       <h2 id="rfc.section.4.4"><a href="#rfc.section.4.4">4.4</a>&nbsp;<a id="message.length" href="#message.length">Message Length</a></h2>
    1176       <p id="rfc.section.4.4.p.1">The transfer-length of a message is the length of the message-body as it appears in the message; that is, after any transfer-codings
     1174      <h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a>&nbsp;<a id="message.length" href="#message.length">Message Length</a></h2>
     1175      <p id="rfc.section.3.4.p.1">The transfer-length of a message is the length of the message-body as it appears in the message; that is, after any transfer-codings
    11771176         have been applied. When a message-body is included with a message, the transfer-length of that body is determined by one of
    11781177         the following (in order of precedence):
    11791178      </p>
    1180       <p id="rfc.section.4.4.p.2"> </p>
     1179      <p id="rfc.section.3.4.p.2"> </p>
    11811180      <ol>
    11821181         <li>
     
    11861185         </li>
    11871186         <li>
    1188             <p>If a Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.3" title="Transfer-Encoding">Section&nbsp;8.7</a>) is present and the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.4</a>) is used, the transfer-length is defined by the use of this transfer-coding. If a Transfer-Encoding header field is present
     1187            <p>If a Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.3" title="Transfer-Encoding">Section&nbsp;7.7</a>) is present and the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section&nbsp;2.4</a>) is used, the transfer-length is defined by the use of this transfer-coding. If a Transfer-Encoding header field is present
    11891188               and the "chunked" transfer-coding is not present, the transfer-length is defined by the sender closing the connection.
    11901189            </p>
    11911190         </li>
    11921191         <li>
    1193             <p>If a Content-Length header field (<a href="#header.content-length" id="rfc.xref.header.content-length.1" title="Content-Length">Section&nbsp;8.2</a>) is present, its decimal value in OCTETs represents both the entity-length and the transfer-length. The Content-Length header
     1192            <p>If a Content-Length header field (<a href="#header.content-length" id="rfc.xref.header.content-length.1" title="Content-Length">Section&nbsp;7.2</a>) is present, its decimal value in OCTETs represents both the entity-length and the transfer-length. The Content-Length header
    11941193               field <em class="bcp14">MUST NOT</em> be sent if these two lengths are different (i.e., if a Transfer-Encoding header field is present). If a message is received
    11951194               with both a Transfer-Encoding header field and a Content-Length header field, the latter <em class="bcp14">MUST</em> be ignored.
     
    12121211         </li>
    12131212      </ol>
    1214       <p id="rfc.section.4.4.p.3">For compatibility with HTTP/1.0 applications, HTTP/1.1 requests containing a message-body <em class="bcp14">MUST</em> include a valid Content-Length header field unless the server is known to be HTTP/1.1 compliant. If a request contains a message-body
     1213      <p id="rfc.section.3.4.p.3">For compatibility with HTTP/1.0 applications, HTTP/1.1 requests containing a message-body <em class="bcp14">MUST</em> include a valid Content-Length header field unless the server is known to be HTTP/1.1 compliant. If a request contains a message-body
    12151214         and a Content-Length is not given, the server <em class="bcp14">SHOULD</em> respond with 400 (Bad Request) if it cannot determine the length of the message, or with 411 (Length Required) if it wishes
    12161215         to insist on receiving a valid Content-Length.
    12171216      </p>
    1218       <p id="rfc.section.4.4.p.4">All HTTP/1.1 applications that receive entities <em class="bcp14">MUST</em> accept the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.4</a>), thus allowing this mechanism to be used for messages when the message length cannot be determined in advance.
    1219       </p>
    1220       <p id="rfc.section.4.4.p.5">Messages <em class="bcp14">MUST NOT</em> include both a Content-Length header field and a transfer-coding. If the message does include a transfer-coding, the Content-Length <em class="bcp14">MUST</em> be ignored.
    1221       </p>
    1222       <p id="rfc.section.4.4.p.6">When a Content-Length is given in a message where a message-body is allowed, its field value <em class="bcp14">MUST</em> exactly match the number of OCTETs in the message-body. HTTP/1.1 user agents <em class="bcp14">MUST</em> notify the user when an invalid length is received and detected.
    1223       </p>
    1224       <h2 id="rfc.section.4.5"><a href="#rfc.section.4.5">4.5</a>&nbsp;<a id="general.header.fields" href="#general.header.fields">General Header Fields</a></h2>
    1225       <p id="rfc.section.4.5.p.1">There are a few header fields which have general applicability for both request and response messages, but which do not apply
     1217      <p id="rfc.section.3.4.p.4">All HTTP/1.1 applications that receive entities <em class="bcp14">MUST</em> accept the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section&nbsp;2.4</a>), thus allowing this mechanism to be used for messages when the message length cannot be determined in advance.
     1218      </p>
     1219      <p id="rfc.section.3.4.p.5">Messages <em class="bcp14">MUST NOT</em> include both a Content-Length header field and a transfer-coding. If the message does include a transfer-coding, the Content-Length <em class="bcp14">MUST</em> be ignored.
     1220      </p>
     1221      <p id="rfc.section.3.4.p.6">When a Content-Length is given in a message where a message-body is allowed, its field value <em class="bcp14">MUST</em> exactly match the number of OCTETs in the message-body. HTTP/1.1 user agents <em class="bcp14">MUST</em> notify the user when an invalid length is received and detected.
     1222      </p>
     1223      <h2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a>&nbsp;<a id="general.header.fields" href="#general.header.fields">General Header Fields</a></h2>
     1224      <p id="rfc.section.3.5.p.1">There are a few header fields which have general applicability for both request and response messages, but which do not apply
    12261225         to the entity being transferred. These header fields apply only to the message being transmitted.
    12271226      </p>
    12281227      <div id="rfc.figure.u.31"></div><pre class="inline"><span id="rfc.iref.g.61"></span>  <a href="#general.header.fields" class="smpl">general-header</a> = <a href="#abnf.dependencies" class="smpl">Cache-Control</a>            ; <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 16.2</a>
    1229                  / <a href="#header.connection" class="smpl">Connection</a>               ; <a href="#header.connection" id="rfc.xref.header.connection.1" title="Connection">Section&nbsp;8.1</a>
    1230                  / <a href="#header.date" class="smpl">Date</a>                     ; <a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section&nbsp;8.3</a>
     1228                 / <a href="#header.connection" class="smpl">Connection</a>               ; <a href="#header.connection" id="rfc.xref.header.connection.1" title="Connection">Section&nbsp;7.1</a>
     1229                 / <a href="#header.date" class="smpl">Date</a>                     ; <a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section&nbsp;7.3</a>
    12311230                 / <a href="#abnf.dependencies" class="smpl">Pragma</a>                   ; <a href="#Part6" id="rfc.xref.Part6.6"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>
    1232                  / <a href="#header.trailer" class="smpl">Trailer</a>                  ; <a href="#header.trailer" id="rfc.xref.header.trailer.2" title="Trailer">Section&nbsp;8.6</a>
    1233                  / <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a>        ; <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.4" title="Transfer-Encoding">Section&nbsp;8.7</a>
    1234                  / <a href="#header.upgrade" class="smpl">Upgrade</a>                  ; <a href="#header.upgrade" id="rfc.xref.header.upgrade.1" title="Upgrade">Section&nbsp;8.8</a>
    1235                  / <a href="#header.via" class="smpl">Via</a>                      ; <a href="#header.via" id="rfc.xref.header.via.1" title="Via">Section&nbsp;8.9</a>
     1231                 / <a href="#header.trailer" class="smpl">Trailer</a>                  ; <a href="#header.trailer" id="rfc.xref.header.trailer.2" title="Trailer">Section&nbsp;7.6</a>
     1232                 / <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a>        ; <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.4" title="Transfer-Encoding">Section&nbsp;7.7</a>
     1233                 / <a href="#header.upgrade" class="smpl">Upgrade</a>                  ; <a href="#header.upgrade" id="rfc.xref.header.upgrade.1" title="Upgrade">Section&nbsp;7.8</a>
     1234                 / <a href="#header.via" class="smpl">Via</a>                      ; <a href="#header.via" id="rfc.xref.header.via.1" title="Via">Section&nbsp;7.9</a>
    12361235                 / <a href="#abnf.dependencies" class="smpl">Warning</a>                  ; <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.warning" title="Warning">Section 16.6</a>
    1237 </pre><p id="rfc.section.4.5.p.3">General-header field names can be extended reliably only in combination with a change in the protocol version. However, new
     1236</pre><p id="rfc.section.3.5.p.3">General-header field names can be extended reliably only in combination with a change in the protocol version. However, new
    12381237         or experimental header fields may be given the semantics of general header fields if all parties in the communication recognize
    12391238         them to be general-header fields. Unrecognized header fields are treated as entity-header fields.
    12401239      </p>
    1241       <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a id="request" href="#request">Request</a></h1>
    1242       <p id="rfc.section.5.p.1">A request message from a client to a server includes, within the first line of that message, the method to be applied to the
     1240      <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a id="request" href="#request">Request</a></h1>
     1241      <p id="rfc.section.4.p.1">A request message from a client to a server includes, within the first line of that message, the method to be applied to the
    12431242         resource, the identifier of the resource, and the protocol version in use.
    12441243      </p>
    1245       <div id="rfc.figure.u.32"></div><pre class="inline"><span id="rfc.iref.g.62"></span>  <a href="#request" class="smpl">Request</a>       = <a href="#request-line" class="smpl">Request-Line</a>              ; <a href="#request-line" title="Request-Line">Section&nbsp;5.1</a>
    1246                   *(( <a href="#general.header.fields" class="smpl">general-header</a>        ; <a href="#general.header.fields" title="General Header Fields">Section&nbsp;4.5</a>
     1244      <div id="rfc.figure.u.32"></div><pre class="inline"><span id="rfc.iref.g.62"></span>  <a href="#request" class="smpl">Request</a>       = <a href="#request-line" class="smpl">Request-Line</a>              ; <a href="#request-line" title="Request-Line">Section&nbsp;4.1</a>
     1245                  *(( <a href="#general.header.fields" class="smpl">general-header</a>        ; <a href="#general.header.fields" title="General Header Fields">Section&nbsp;3.5</a>
    12471246                   / <a href="#abnf.dependencies" class="smpl">request-header</a>         ; <a href="#Part2" id="rfc.xref.Part2.7"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a>
    12481247                   / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#core.rules" class="smpl">CRLF</a>)  ; <a href="#Part3" id="rfc.xref.Part3.10"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>
    12491248                  <a href="#core.rules" class="smpl">CRLF</a>
    1250                   [ <a href="#message.body" class="smpl">message-body</a> ]          ; <a href="#message.body" title="Message Body">Section&nbsp;4.3</a>
    1251 </pre><h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a>&nbsp;<a id="request-line" href="#request-line">Request-Line</a></h2>
    1252       <p id="rfc.section.5.1.p.1">The Request-Line begins with a method token, followed by the Request-URI and the protocol version, and ending with CRLF. The
     1249                  [ <a href="#message.body" class="smpl">message-body</a> ]          ; <a href="#message.body" title="Message Body">Section&nbsp;3.3</a>
     1250</pre><h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a id="request-line" href="#request-line">Request-Line</a></h2>
     1251      <p id="rfc.section.4.1.p.1">The Request-Line begins with a method token, followed by the Request-URI and the protocol version, and ending with CRLF. The
    12531252         elements are separated by SP characters. No CR or LF is allowed except in the final CRLF sequence.
    12541253      </p>
    12551254      <div id="rfc.figure.u.33"></div><pre class="inline"><span id="rfc.iref.g.63"></span>  <a href="#request-line" class="smpl">Request-Line</a>   = <a href="#method" class="smpl">Method</a> <a href="#core.rules" class="smpl">SP</a> <a href="#request-uri" class="smpl">Request-URI</a> <a href="#core.rules" class="smpl">SP</a> <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#core.rules" class="smpl">CRLF</a>
    1256 </pre><h3 id="rfc.section.5.1.1"><a href="#rfc.section.5.1.1">5.1.1</a>&nbsp;<a id="method" href="#method">Method</a></h3>
    1257       <p id="rfc.section.5.1.1.p.1">The Method token indicates the method to be performed on the resource identified by the Request-URI. The method is case-sensitive.</p>
     1255</pre><h3 id="rfc.section.4.1.1"><a href="#rfc.section.4.1.1">4.1.1</a>&nbsp;<a id="method" href="#method">Method</a></h3>
     1256      <p id="rfc.section.4.1.1.p.1">The Method token indicates the method to be performed on the resource identified by the Request-URI. The method is case-sensitive.</p>
    12581257      <div id="rfc.figure.u.34"></div><pre class="inline"><span id="rfc.iref.g.64"></span><span id="rfc.iref.g.65"></span>  <a href="#method" class="smpl">Method</a>         = <a href="#rule.token.separators" class="smpl">token</a>
    1259 </pre><h3 id="rfc.section.5.1.2"><a href="#rfc.section.5.1.2">5.1.2</a>&nbsp;<a id="request-uri" href="#request-uri">Request-URI</a></h3>
    1260       <p id="rfc.section.5.1.2.p.1">The Request-URI is a Uniform Resource Identifier (<a href="#uri" title="Uniform Resource Identifiers">Section&nbsp;3.2</a>) and identifies the resource upon which to apply the request.
     1258</pre><h3 id="rfc.section.4.1.2"><a href="#rfc.section.4.1.2">4.1.2</a>&nbsp;<a id="request-uri" href="#request-uri">Request-URI</a></h3>
     1259      <p id="rfc.section.4.1.2.p.1">The Request-URI is a Uniform Resource Identifier (<a href="#uri" title="Uniform Resource Identifiers">Section&nbsp;2.2</a>) and identifies the resource upon which to apply the request.
    12611260      </p>
    12621261      <div id="rfc.figure.u.35"></div><pre class="inline"><span id="rfc.iref.g.66"></span>  <a href="#request-uri" class="smpl">Request-URI</a>    = "*"
     
    12641263                 / ( <a href="#uri" class="smpl">path-absolute</a> [ "?" <a href="#uri" class="smpl">query</a> ] )
    12651264                 / <a href="#uri" class="smpl">authority</a>
    1266 </pre><p id="rfc.section.5.1.2.p.3">The four options for Request-URI are dependent on the nature of the request. The asterisk "*" means that the request does
     1265</pre><p id="rfc.section.4.1.2.p.3">The four options for Request-URI are dependent on the nature of the request. The asterisk "*" means that the request does
    12671266         not apply to a particular resource, but to the server itself, and is only allowed when the method used does not necessarily
    12681267         apply to a resource. One example would be
    12691268      </p>
    12701269      <div id="rfc.figure.u.36"></div><pre class="text">    OPTIONS * HTTP/1.1
    1271 </pre><p id="rfc.section.5.1.2.p.5">The absolute-URI form is <em class="bcp14">REQUIRED</em> when the request is being made to a proxy. The proxy is requested to forward the request or service it from a valid cache,
     1270</pre><p id="rfc.section.4.1.2.p.5">The absolute-URI form is <em class="bcp14">REQUIRED</em> when the request is being made to a proxy. The proxy is requested to forward the request or service it from a valid cache,
    12721271         and return the response. Note that the proxy <em class="bcp14">MAY</em> forward the request on to another proxy or directly to the server specified by the absolute-URI. In order to avoid request
    12731272         loops, a proxy <em class="bcp14">MUST</em> be able to recognize all of its server names, including any aliases, local variations, and the numeric IP address. An example
     
    12751274      </p>
    12761275      <div id="rfc.figure.u.37"></div><pre class="text">    GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1
    1277 </pre><p id="rfc.section.5.1.2.p.7">To allow for transition to absolute-URIs in all requests in future versions of HTTP, all HTTP/1.1 servers <em class="bcp14">MUST</em> accept the absolute-URI form in requests, even though HTTP/1.1 clients will only generate them in requests to proxies.
    1278       </p>
    1279       <p id="rfc.section.5.1.2.p.8">The authority form is only used by the CONNECT method (<a href="p2-semantics.html#CONNECT" title="CONNECT">Section 8.9</a> of <a href="#Part2" id="rfc.xref.Part2.8"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).
    1280       </p>
    1281       <p id="rfc.section.5.1.2.p.9">The most common form of Request-URI is that used to identify a resource on an origin server or gateway. In this case the absolute
    1282          path of the URI <em class="bcp14">MUST</em> be transmitted (see <a href="#http.uri" title="http URI scheme">Section&nbsp;3.2.1</a>, path-absolute) as the Request-URI, and the network location of the URI (authority) <em class="bcp14">MUST</em> be transmitted in a Host header field. For example, a client wishing to retrieve the resource above directly from the origin
     1276</pre><p id="rfc.section.4.1.2.p.7">To allow for transition to absolute-URIs in all requests in future versions of HTTP, all HTTP/1.1 servers <em class="bcp14">MUST</em> accept the absolute-URI form in requests, even though HTTP/1.1 clients will only generate them in requests to proxies.
     1277      </p>
     1278      <p id="rfc.section.4.1.2.p.8">The authority form is only used by the CONNECT method (<a href="p2-semantics.html#CONNECT" title="CONNECT">Section 8.9</a> of <a href="#Part2" id="rfc.xref.Part2.8"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).
     1279      </p>
     1280      <p id="rfc.section.4.1.2.p.9">The most common form of Request-URI is that used to identify a resource on an origin server or gateway. In this case the absolute
     1281         path of the URI <em class="bcp14">MUST</em> be transmitted (see <a href="#http.uri" title="http URI scheme">Section&nbsp;2.2.1</a>, path-absolute) as the Request-URI, and the network location of the URI (authority) <em class="bcp14">MUST</em> be transmitted in a Host header field. For example, a client wishing to retrieve the resource above directly from the origin
    12831282         server would create a TCP connection to port 80 of the host "www.example.org" and send the lines:
    12841283      </p>
    12851284      <div id="rfc.figure.u.38"></div><pre class="text">    GET /pub/WWW/TheProject.html HTTP/1.1
    12861285    Host: www.example.org
    1287 </pre><p id="rfc.section.5.1.2.p.11">followed by the remainder of the Request. Note that the absolute path cannot be empty; if none is present in the original
     1286</pre><p id="rfc.section.4.1.2.p.11">followed by the remainder of the Request. Note that the absolute path cannot be empty; if none is present in the original
    12881287         URI, it <em class="bcp14">MUST</em> be given as "/" (the server root).
    12891288      </p>
    1290       <p id="rfc.section.5.1.2.p.12">The Request-URI is transmitted in the format specified in <a href="#http.uri" title="http URI scheme">Section&nbsp;3.2.1</a>. If the Request-URI is encoded using the "% <a href="#core.rules" class="smpl">HEXDIG</a>  <a href="#core.rules" class="smpl">HEXDIG</a>" encoding (<a href="#RFC3986" id="rfc.xref.RFC3986.14"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.4">Section 2.4</a>), the origin server <em class="bcp14">MUST</em> decode the Request-URI in order to properly interpret the request. Servers <em class="bcp14">SHOULD</em> respond to invalid Request-URIs with an appropriate status code.
    1291       </p>
    1292       <p id="rfc.section.5.1.2.p.13">A transparent proxy <em class="bcp14">MUST NOT</em> rewrite the "path-absolute" part of the received Request-URI when forwarding it to the next inbound server, except as noted
     1289      <p id="rfc.section.4.1.2.p.12">The Request-URI is transmitted in the format specified in <a href="#http.uri" title="http URI scheme">Section&nbsp;2.2.1</a>. If the Request-URI is encoded using the "% <a href="#core.rules" class="smpl">HEXDIG</a>  <a href="#core.rules" class="smpl">HEXDIG</a>" encoding (<a href="#RFC3986" id="rfc.xref.RFC3986.14"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.4">Section 2.4</a>), the origin server <em class="bcp14">MUST</em> decode the Request-URI in order to properly interpret the request. Servers <em class="bcp14">SHOULD</em> respond to invalid Request-URIs with an appropriate status code.
     1290      </p>
     1291      <p id="rfc.section.4.1.2.p.13">A transparent proxy <em class="bcp14">MUST NOT</em> rewrite the "path-absolute" part of the received Request-URI when forwarding it to the next inbound server, except as noted
    12931292         above to replace a null path-absolute with "/".
    12941293      </p>
    1295       <p id="rfc.section.5.1.2.p.14"> </p>
     1294      <p id="rfc.section.4.1.2.p.14"> </p>
    12961295      <dl class="empty">
    12971296         <dd> <b>Note:</b> The "no rewrite" rule prevents the proxy from changing the meaning of the request when the origin server is improperly using
     
    13001299         </dd>
    13011300      </dl>
    1302       <h2 id="rfc.section.5.2"><a href="#rfc.section.5.2">5.2</a>&nbsp;<a id="the.resource.identified.by.a.request" href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></h2>
    1303       <p id="rfc.section.5.2.p.1">The exact resource identified by an Internet request is determined by examining both the Request-URI and the Host header field.</p>
    1304       <p id="rfc.section.5.2.p.2">An origin server that does not allow resources to differ by the requested host <em class="bcp14">MAY</em> ignore the Host header field value when determining the resource identified by an HTTP/1.1 request. (But see <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">Appendix&nbsp;B.1.1</a> for other requirements on Host support in HTTP/1.1.)
    1305       </p>
    1306       <p id="rfc.section.5.2.p.3">An origin server that does differentiate resources based on the host requested (sometimes referred to as virtual hosts or
     1301      <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a>&nbsp;<a id="the.resource.identified.by.a.request" href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></h2>
     1302      <p id="rfc.section.4.2.p.1">The exact resource identified by an Internet request is determined by examining both the Request-URI and the Host header field.</p>
     1303      <p id="rfc.section.4.2.p.2">An origin server that does not allow resources to differ by the requested host <em class="bcp14">MAY</em> ignore the Host header field value when determining the resource identified by an HTTP/1.1 request. (But see <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">Appendix&nbsp;B.1.1</a> for other requirements on Host support in HTTP/1.1.)
     1304      </p>
     1305      <p id="rfc.section.4.2.p.3">An origin server that does differentiate resources based on the host requested (sometimes referred to as virtual hosts or
    13071306         vanity host names) <em class="bcp14">MUST</em> use the following rules for determining the requested resource on an HTTP/1.1 request:
    13081307      </p>
     
    13161315         </li>
    13171316      </ol>
    1318       <p id="rfc.section.5.2.p.4">Recipients of an HTTP/1.0 request that lacks a Host header field <em class="bcp14">MAY</em> attempt to use heuristics (e.g., examination of the URI path for something unique to a particular host) in order to determine
     1317      <p id="rfc.section.4.2.p.4">Recipients of an HTTP/1.0 request that lacks a Host header field <em class="bcp14">MAY</em> attempt to use heuristics (e.g., examination of the URI path for something unique to a particular host) in order to determine
    13191318         what exact resource is being requested.
    13201319      </p>
    1321       <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="response" href="#response">Response</a></h1>
    1322       <p id="rfc.section.6.p.1">After receiving and interpreting a request message, a server responds with an HTTP response message.</p>
    1323       <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.67"></span>  <a href="#response" class="smpl">Response</a>      = <a href="#status-line" class="smpl">Status-Line</a>               ; <a href="#status-line" title="Status-Line">Section&nbsp;6.1</a>
    1324                   *(( <a href="#general.header.fields" class="smpl">general-header</a>        ; <a href="#general.header.fields" title="General Header Fields">Section&nbsp;4.5</a>
     1320      <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a id="response" href="#response">Response</a></h1>
     1321      <p id="rfc.section.5.p.1">After receiving and interpreting a request message, a server responds with an HTTP response message.</p>
     1322      <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.67"></span>  <a href="#response" class="smpl">Response</a>      = <a href="#status-line" class="smpl">Status-Line</a>               ; <a href="#status-line" title="Status-Line">Section&nbsp;5.1</a>
     1323                  *(( <a href="#general.header.fields" class="smpl">general-header</a>        ; <a href="#general.header.fields" title="General Header Fields">Section&nbsp;3.5</a>
    13251324                   / <a href="#abnf.dependencies" class="smpl">response-header</a>        ; <a href="#Part2" id="rfc.xref.Part2.9"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#response.header.fields" title="Response Header Fields">Section 6</a>
    13261325                   / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#core.rules" class="smpl">CRLF</a>)  ; <a href="#Part3" id="rfc.xref.Part3.11"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>
    13271326                  <a href="#core.rules" class="smpl">CRLF</a>
    1328                   [ <a href="#message.body" class="smpl">message-body</a> ]          ; <a href="#message.body" title="Message Body">Section&nbsp;4.3</a>
    1329 </pre><h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a id="status-line" href="#status-line">Status-Line</a></h2>
    1330       <p id="rfc.section.6.1.p.1">The first line of a Response message is the Status-Line, consisting of the protocol version followed by a numeric status code
     1327                  [ <a href="#message.body" class="smpl">message-body</a> ]          ; <a href="#message.body" title="Message Body">Section&nbsp;3.3</a>
     1328</pre><h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a>&nbsp;<a id="status-line" href="#status-line">Status-Line</a></h2>
     1329      <p id="rfc.section.5.1.p.1">The first line of a Response message is the Status-Line, consisting of the protocol version followed by a numeric status code
    13311330         and its associated textual phrase, with each element separated by SP characters. No CR or LF is allowed except in the final
    13321331         CRLF sequence.
    13331332      </p>
    13341333      <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.68"></span>  <a href="#status-line" class="smpl">Status-Line</a> = <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a> <a href="#core.rules" class="smpl">CRLF</a>
    1335 </pre><h3 id="rfc.section.6.1.1"><a href="#rfc.section.6.1.1">6.1.1</a>&nbsp;<a id="status.code.and.reason.phrase" href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h3>
    1336       <p id="rfc.section.6.1.1.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request. These codes
     1334</pre><h3 id="rfc.section.5.1.1"><a href="#rfc.section.5.1.1">5.1.1</a>&nbsp;<a id="status.code.and.reason.phrase" href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h3>
     1335      <p id="rfc.section.5.1.1.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request. These codes
    13371336         are fully defined in <a href="p2-semantics.html#status.codes" title="Status Code Definitions">Section 9</a> of <a href="#Part2" id="rfc.xref.Part2.10"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>. The Reason Phrase exists for the sole purpose of providing a textual description associated with the numeric status code,
    13381337         out of deference to earlier Internet application protocols that were more frequently used with interactive text clients. A
    13391338         client <em class="bcp14">SHOULD</em> ignore the content of the Reason Phrase.
    13401339      </p>
    1341       <p id="rfc.section.6.1.1.p.2">The first digit of the Status-Code defines the class of response. The last two digits do not have any categorization role.
     1340      <p id="rfc.section.5.1.1.p.2">The first digit of the Status-Code defines the class of response. The last two digits do not have any categorization role.
    13421341         There are 5 values for the first digit:
    13431342      </p>
     
    13511350      <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.69"></span><span id="rfc.iref.g.70"></span><span id="rfc.iref.g.71"></span>  <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a>    = 3<a href="#core.rules" class="smpl">DIGIT</a>
    13521351  <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a>  = *&lt;<a href="#rule.TEXT" class="smpl">TEXT</a>, excluding <a href="#core.rules" class="smpl">CR</a>, <a href="#core.rules" class="smpl">LF</a>&gt;
    1353 </pre><h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="connections" href="#connections">Connections</a></h1>
    1354       <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a id="persistent.connections" href="#persistent.connections">Persistent Connections</a></h2>
    1355       <h3 id="rfc.section.7.1.1"><a href="#rfc.section.7.1.1">7.1.1</a>&nbsp;<a id="persistent.purpose" href="#persistent.purpose">Purpose</a></h3>
    1356       <p id="rfc.section.7.1.1.p.1">Prior to persistent connections, a separate TCP connection was established to fetch each URL, increasing the load on HTTP
     1352</pre><h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="connections" href="#connections">Connections</a></h1>
     1353      <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a id="persistent.connections" href="#persistent.connections">Persistent Connections</a></h2>
     1354      <h3 id="rfc.section.6.1.1"><a href="#rfc.section.6.1.1">6.1.1</a>&nbsp;<a id="persistent.purpose" href="#persistent.purpose">Purpose</a></h3>
     1355      <p id="rfc.section.6.1.1.p.1">Prior to persistent connections, a separate TCP connection was established to fetch each URL, increasing the load on HTTP
    13571356         servers and causing congestion on the Internet. The use of inline images and other associated data often require a client
    13581357         to make multiple requests of the same server in a short amount of time. Analysis of these performance problems and results
    13591358         from a prototype implementation are available <a href="#Pad1995" id="rfc.xref.Pad1995.1"><cite title="Improving HTTP Latency">[Pad1995]</cite></a>  <a href="#Spe" id="rfc.xref.Spe.1"><cite title="Analysis of HTTP Performance Problems">[Spe]</cite></a>. Implementation experience and measurements of actual HTTP/1.1 (<cite title="Hypertext Transfer Protocol -- HTTP/1.1" id="rfc.xref.RFC2068.2">RFC 2068</cite>) implementations show good results <a href="#Nie1997" id="rfc.xref.Nie1997.1"><cite title="Network Performance Effects of HTTP/1.1, CSS1, and PNG">[Nie1997]</cite></a>. Alternatives have also been explored, for example, T/TCP <a href="#Tou1998" id="rfc.xref.Tou1998.1"><cite title="Analysis of HTTP Performance">[Tou1998]</cite></a>.
    13601359      </p>
    1361       <p id="rfc.section.7.1.1.p.2">Persistent HTTP connections have a number of advantages: </p>
     1360      <p id="rfc.section.6.1.1.p.2">Persistent HTTP connections have a number of advantages: </p>
    13621361      <ul>
    13631362         <li>By opening and closing fewer TCP connections, CPU time is saved in routers and hosts (clients, servers, proxies, gateways,
     
    13761375         </li>
    13771376      </ul>
    1378       <p id="rfc.section.7.1.1.p.3">HTTP implementations <em class="bcp14">SHOULD</em> implement persistent connections.
    1379       </p>
    1380       <h3 id="rfc.section.7.1.2"><a href="#rfc.section.7.1.2">7.1.2</a>&nbsp;<a id="persistent.overall" href="#persistent.overall">Overall Operation</a></h3>
    1381       <p id="rfc.section.7.1.2.p.1">A significant difference between HTTP/1.1 and earlier versions of HTTP is that persistent connections are the default behavior
     1377      <p id="rfc.section.6.1.1.p.3">HTTP implementations <em class="bcp14">SHOULD</em> implement persistent connections.
     1378      </p>
     1379      <h3 id="rfc.section.6.1.2"><a href="#rfc.section.6.1.2">6.1.2</a>&nbsp;<a id="persistent.overall" href="#persistent.overall">Overall Operation</a></h3>
     1380      <p id="rfc.section.6.1.2.p.1">A significant difference between HTTP/1.1 and earlier versions of HTTP is that persistent connections are the default behavior
    13821381         of any HTTP connection. That is, unless otherwise indicated, the client <em class="bcp14">SHOULD</em> assume that the server will maintain a persistent connection, even after error responses from the server.
    13831382      </p>
    1384       <p id="rfc.section.7.1.2.p.2">Persistent connections provide a mechanism by which a client and a server can signal the close of a TCP connection. This signaling
    1385          takes place using the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.2" title="Connection">Section&nbsp;8.1</a>). Once a close has been signaled, the client <em class="bcp14">MUST NOT</em> send any more requests on that connection.
    1386       </p>
    1387       <h4 id="rfc.section.7.1.2.1"><a href="#rfc.section.7.1.2.1">7.1.2.1</a>&nbsp;<a id="persistent.negotiation" href="#persistent.negotiation">Negotiation</a></h4>
    1388       <p id="rfc.section.7.1.2.1.p.1">An HTTP/1.1 server <em class="bcp14">MAY</em> assume that a HTTP/1.1 client intends to maintain a persistent connection unless a Connection header including the connection-token
     1383      <p id="rfc.section.6.1.2.p.2">Persistent connections provide a mechanism by which a client and a server can signal the close of a TCP connection. This signaling
     1384         takes place using the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.2" title="Connection">Section&nbsp;7.1</a>). Once a close has been signaled, the client <em class="bcp14">MUST NOT</em> send any more requests on that connection.
     1385      </p>
     1386      <h4 id="rfc.section.6.1.2.1"><a href="#rfc.section.6.1.2.1">6.1.2.1</a>&nbsp;<a id="persistent.negotiation" href="#persistent.negotiation">Negotiation</a></h4>
     1387      <p id="rfc.section.6.1.2.1.p.1">An HTTP/1.1 server <em class="bcp14">MAY</em> assume that a HTTP/1.1 client intends to maintain a persistent connection unless a Connection header including the connection-token
    13891388         "close" was sent in the request. If the server chooses to close the connection immediately after sending the response, it <em class="bcp14">SHOULD</em> send a Connection header including the connection-token close.
    13901389      </p>
    1391       <p id="rfc.section.7.1.2.1.p.2">An HTTP/1.1 client <em class="bcp14">MAY</em> expect a connection to remain open, but would decide to keep it open based on whether the response from a server contains
     1390      <p id="rfc.section.6.1.2.1.p.2">An HTTP/1.1 client <em class="bcp14">MAY</em> expect a connection to remain open, but would decide to keep it open based on whether the response from a server contains
    13921391         a Connection header with the connection-token close. In case the client does not want to maintain a connection for more than
    13931392         that request, it <em class="bcp14">SHOULD</em> send a Connection header including the connection-token close.
    13941393      </p>
    1395       <p id="rfc.section.7.1.2.1.p.3">If either the client or the server sends the close token in the Connection header, that request becomes the last one for the
     1394      <p id="rfc.section.6.1.2.1.p.3">If either the client or the server sends the close token in the Connection header, that request becomes the last one for the
    13961395         connection.
    13971396      </p>
    1398       <p id="rfc.section.7.1.2.1.p.4">Clients and servers <em class="bcp14">SHOULD NOT</em> assume that a persistent connection is maintained for HTTP versions less than 1.1 unless it is explicitly signaled. See <a href="#compatibility.with.http.1.0.persistent.connections" title="Compatibility with HTTP/1.0 Persistent Connections">Appendix&nbsp;B.2</a> for more information on backward compatibility with HTTP/1.0 clients.
    1399       </p>
    1400       <p id="rfc.section.7.1.2.1.p.5">In order to remain persistent, all messages on the connection <em class="bcp14">MUST</em> have a self-defined message length (i.e., one not defined by closure of the connection), as described in <a href="#message.length" title="Message Length">Section&nbsp;4.4</a>.
    1401       </p>
    1402       <h4 id="rfc.section.7.1.2.2"><a href="#rfc.section.7.1.2.2">7.1.2.2</a>&nbsp;<a id="pipelining" href="#pipelining">Pipelining</a></h4>
    1403       <p id="rfc.section.7.1.2.2.p.1">A client that supports persistent connections <em class="bcp14">MAY</em> "pipeline" its requests (i.e., send multiple requests without waiting for each response). A server <em class="bcp14">MUST</em> send its responses to those requests in the same order that the requests were received.
    1404       </p>
    1405       <p id="rfc.section.7.1.2.2.p.2">Clients which assume persistent connections and pipeline immediately after connection establishment <em class="bcp14">SHOULD</em> be prepared to retry their connection if the first pipelined attempt fails. If a client does such a retry, it <em class="bcp14">MUST NOT</em> pipeline before it knows the connection is persistent. Clients <em class="bcp14">MUST</em> also be prepared to resend their requests if the server closes the connection before sending all of the corresponding responses.
    1406       </p>
    1407       <p id="rfc.section.7.1.2.2.p.3">Clients <em class="bcp14">SHOULD NOT</em> pipeline requests using non-idempotent methods or non-idempotent sequences of methods (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 8.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.11"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Otherwise, a premature termination of the transport connection could lead to indeterminate results. A client wishing to
     1397      <p id="rfc.section.6.1.2.1.p.4">Clients and servers <em class="bcp14">SHOULD NOT</em> assume that a persistent connection is maintained for HTTP versions less than 1.1 unless it is explicitly signaled. See <a href="#compatibility.with.http.1.0.persistent.connections" title="Compatibility with HTTP/1.0 Persistent Connections">Appendix&nbsp;B.2</a> for more information on backward compatibility with HTTP/1.0 clients.
     1398      </p>
     1399      <p id="rfc.section.6.1.2.1.p.5">In order to remain persistent, all messages on the connection <em class="bcp14">MUST</em> have a self-defined message length (i.e., one not defined by closure of the connection), as described in <a href="#message.length" title="Message Length">Section&nbsp;3.4</a>.
     1400      </p>
     1401      <h4 id="rfc.section.6.1.2.2"><a href="#rfc.section.6.1.2.2">6.1.2.2</a>&nbsp;<a id="pipelining" href="#pipelining">Pipelining</a></h4>
     1402      <p id="rfc.section.6.1.2.2.p.1">A client that supports persistent connections <em class="bcp14">MAY</em> "pipeline" its requests (i.e., send multiple requests without waiting for each response). A server <em class="bcp14">MUST</em> send its responses to those requests in the same order that the requests were received.
     1403      </p>
     1404      <p id="rfc.section.6.1.2.2.p.2">Clients which assume persistent connections and pipeline immediately after connection establishment <em class="bcp14">SHOULD</em> be prepared to retry their connection if the first pipelined attempt fails. If a client does such a retry, it <em class="bcp14">MUST NOT</em> pipeline before it knows the connection is persistent. Clients <em class="bcp14">MUST</em> also be prepared to resend their requests if the server closes the connection before sending all of the corresponding responses.
     1405      </p>
     1406      <p id="rfc.section.6.1.2.2.p.3">Clients <em class="bcp14">SHOULD NOT</em> pipeline requests using non-idempotent methods or non-idempotent sequences of methods (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 8.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.11"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Otherwise, a premature termination of the transport connection could lead to indeterminate results. A client wishing to
    14081407         send a non-idempotent request <em class="bcp14">SHOULD</em> wait to send that request until it has received the response status for the previous request.
    14091408      </p>
    1410       <h3 id="rfc.section.7.1.3"><a href="#rfc.section.7.1.3">7.1.3</a>&nbsp;<a id="persistent.proxy" href="#persistent.proxy">Proxy Servers</a></h3>
    1411       <p id="rfc.section.7.1.3.p.1">It is especially important that proxies correctly implement the properties of the Connection header field as specified in <a href="#header.connection" id="rfc.xref.header.connection.3" title="Connection">Section&nbsp;8.1</a>.
    1412       </p>
    1413       <p id="rfc.section.7.1.3.p.2">The proxy server <em class="bcp14">MUST</em> signal persistent connections separately with its clients and the origin servers (or other proxy servers) that it connects
     1409      <h3 id="rfc.section.6.1.3"><a href="#rfc.section.6.1.3">6.1.3</a>&nbsp;<a id="persistent.proxy" href="#persistent.proxy">Proxy Servers</a></h3>
     1410      <p id="rfc.section.6.1.3.p.1">It is especially important that proxies correctly implement the properties of the Connection header field as specified in <a href="#header.connection" id="rfc.xref.header.connection.3" title="Connection">Section&nbsp;7.1</a>.
     1411      </p>
     1412      <p id="rfc.section.6.1.3.p.2">The proxy server <em class="bcp14">MUST</em> signal persistent connections separately with its clients and the origin servers (or other proxy servers) that it connects
    14141413         to. Each persistent connection applies to only one transport link.
    14151414      </p>
    1416       <p id="rfc.section.7.1.3.p.3">A proxy server <em class="bcp14">MUST NOT</em> establish a HTTP/1.1 persistent connection with an HTTP/1.0 client (but see <a href="#RFC2068" id="rfc.xref.RFC2068.3"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> for information and discussion of the problems with the Keep-Alive header implemented by many HTTP/1.0 clients).
    1417       </p>
    1418       <h3 id="rfc.section.7.1.4"><a href="#rfc.section.7.1.4">7.1.4</a>&nbsp;<a id="persistent.practical" href="#persistent.practical">Practical Considerations</a></h3>
    1419       <p id="rfc.section.7.1.4.p.1">Servers will usually have some time-out value beyond which they will no longer maintain an inactive connection. Proxy servers
     1415      <p id="rfc.section.6.1.3.p.3">A proxy server <em class="bcp14">MUST NOT</em> establish a HTTP/1.1 persistent connection with an HTTP/1.0 client (but see <a href="#RFC2068" id="rfc.xref.RFC2068.3"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> for information and discussion of the problems with the Keep-Alive header implemented by many HTTP/1.0 clients).
     1416      </p>
     1417      <h3 id="rfc.section.6.1.4"><a href="#rfc.section.6.1.4">6.1.4</a>&nbsp;<a id="persistent.practical" href="#persistent.practical">Practical Considerations</a></h3>
     1418      <p id="rfc.section.6.1.4.p.1">Servers will usually have some time-out value beyond which they will no longer maintain an inactive connection. Proxy servers
    14201419         might make this a higher value since it is likely that the client will be making more connections through the same server.
    14211420         The use of persistent connections places no requirements on the length (or existence) of this time-out for either the client
    14221421         or the server.
    14231422      </p>
    1424       <p id="rfc.section.7.1.4.p.2">When a client or server wishes to time-out it <em class="bcp14">SHOULD</em> issue a graceful close on the transport connection. Clients and servers <em class="bcp14">SHOULD</em> both constantly watch for the other side of the transport close, and respond to it as appropriate. If a client or server does
     1423      <p id="rfc.section.6.1.4.p.2">When a client or server wishes to time-out it <em class="bcp14">SHOULD</em> issue a graceful close on the transport connection. Clients and servers <em class="bcp14">SHOULD</em> both constantly watch for the other side of the transport close, and respond to it as appropriate. If a client or server does
    14251424         not detect the other side's close promptly it could cause unnecessary resource drain on the network.
    14261425      </p>
    1427       <p id="rfc.section.7.1.4.p.3">A client, server, or proxy <em class="bcp14">MAY</em> close the transport connection at any time. For example, a client might have started to send a new request at the same time
     1426      <p id="rfc.section.6.1.4.p.3">A client, server, or proxy <em class="bcp14">MAY</em> close the transport connection at any time. For example, a client might have started to send a new request at the same time
    14281427         that the server has decided to close the "idle" connection. From the server's point of view, the connection is being closed
    14291428         while it was idle, but from the client's point of view, a request is in progress.
    14301429      </p>
    1431       <p id="rfc.section.7.1.4.p.4">This means that clients, servers, and proxies <em class="bcp14">MUST</em> be able to recover from asynchronous close events. Client software <em class="bcp14">SHOULD</em> reopen the transport connection and retransmit the aborted sequence of requests without user interaction so long as the request
     1430      <p id="rfc.section.6.1.4.p.4">This means that clients, servers, and proxies <em class="bcp14">MUST</em> be able to recover from asynchronous close events. Client software <em class="bcp14">SHOULD</em> reopen the transport connection and retransmit the aborted sequence of requests without user interaction so long as the request
    14321431         sequence is idempotent (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 8.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.12"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Non-idempotent methods or sequences <em class="bcp14">MUST NOT</em> be automatically retried, although user agents <em class="bcp14">MAY</em> offer a human operator the choice of retrying the request(s). Confirmation by user-agent software with semantic understanding
    14331432         of the application <em class="bcp14">MAY</em> substitute for user confirmation. The automatic retry <em class="bcp14">SHOULD NOT</em> be repeated if the second sequence of requests fails.
    14341433      </p>
    1435       <p id="rfc.section.7.1.4.p.5">Servers <em class="bcp14">SHOULD</em> always respond to at least one request per connection, if at all possible. Servers <em class="bcp14">SHOULD NOT</em> close a connection in the middle of transmitting a response, unless a network or client failure is suspected.
    1436       </p>
    1437       <p id="rfc.section.7.1.4.p.6">Clients that use persistent connections <em class="bcp14">SHOULD</em> limit the number of simultaneous connections that they maintain to a given server. A single-user client <em class="bcp14">SHOULD NOT</em> maintain more than 2 connections with any server or proxy. A proxy <em class="bcp14">SHOULD</em> use up to 2*N connections to another server or proxy, where N is the number of simultaneously active users. These guidelines
     1434      <p id="rfc.section.6.1.4.p.5">Servers <em class="bcp14">SHOULD</em> always respond to at least one request per connection, if at all possible. Servers <em class="bcp14">SHOULD NOT</em> close a connection in the middle of transmitting a response, unless a network or client failure is suspected.
     1435      </p>
     1436      <p id="rfc.section.6.1.4.p.6">Clients that use persistent connections <em class="bcp14">SHOULD</em> limit the number of simultaneous connections that they maintain to a given server. A single-user client <em class="bcp14">SHOULD NOT</em> maintain more than 2 connections with any server or proxy. A proxy <em class="bcp14">SHOULD</em> use up to 2*N connections to another server or proxy, where N is the number of simultaneously active users. These guidelines
    14381437         are intended to improve HTTP response times and avoid congestion.
    14391438      </p>
    1440       <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a>&nbsp;<a id="message.transmission.requirements" href="#message.transmission.requirements">Message Transmission Requirements</a></h2>
    1441       <h3 id="rfc.section.7.2.1"><a href="#rfc.section.7.2.1">7.2.1</a>&nbsp;<a id="persistent.flow" href="#persistent.flow">Persistent Connections and Flow Control</a></h3>
    1442       <p id="rfc.section.7.2.1.p.1">HTTP/1.1 servers <em class="bcp14">SHOULD</em> maintain persistent connections and use TCP's flow control mechanisms to resolve temporary overloads, rather than terminating
     1439      <h2 id="rfc.section.6.2"><a href="#rfc.section.6.2">6.2</a>&nbsp;<a id="message.transmission.requirements" href="#message.transmission.requirements">Message Transmission Requirements</a></h2>
     1440      <h3 id="rfc.section.6.2.1"><a href="#rfc.section.6.2.1">6.2.1</a>&nbsp;<a id="persistent.flow" href="#persistent.flow">Persistent Connections and Flow Control</a></h3>
     1441      <p id="rfc.section.6.2.1.p.1">HTTP/1.1 servers <em class="bcp14">SHOULD</em> maintain persistent connections and use TCP's flow control mechanisms to resolve temporary overloads, rather than terminating
    14431442         connections with the expectation that clients will retry. The latter technique can exacerbate network congestion.
    14441443      </p>
    1445       <h3 id="rfc.section.7.2.2"><a href="#rfc.section.7.2.2">7.2.2</a>&nbsp;<a id="persistent.monitor" href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></h3>
    1446       <p id="rfc.section.7.2.2.p.1">An HTTP/1.1 (or later) client sending a message-body <em class="bcp14">SHOULD</em> monitor the network connection for an error status while it is transmitting the request. If the client sees an error status,
    1447          it <em class="bcp14">SHOULD</em> immediately cease transmitting the body. If the body is being sent using a "chunked" encoding (<a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.4</a>), a zero length chunk and empty trailer <em class="bcp14">MAY</em> be used to prematurely mark the end of the message. If the body was preceded by a Content-Length header, the client <em class="bcp14">MUST</em> close the connection.
    1448       </p>
    1449       <h3 id="rfc.section.7.2.3"><a href="#rfc.section.7.2.3">7.2.3</a>&nbsp;<a id="use.of.the.100.status" href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></h3>
    1450       <p id="rfc.section.7.2.3.p.1">The purpose of the 100 (Continue) status (see <a href="p2-semantics.html#status.100" title="100 Continue">Section 9.1.1</a> of <a href="#Part2" id="rfc.xref.Part2.13"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) is to allow a client that is sending a request message with a request body to determine if the origin server is willing
     1444      <h3 id="rfc.section.6.2.2"><a href="#rfc.section.6.2.2">6.2.2</a>&nbsp;<a id="persistent.monitor" href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></h3>
     1445      <p id="rfc.section.6.2.2.p.1">An HTTP/1.1 (or later) client sending a message-body <em class="bcp14">SHOULD</em> monitor the network connection for an error status while it is transmitting the request. If the client sees an error status,
     1446         it <em class="bcp14">SHOULD</em> immediately cease transmitting the body. If the body is being sent using a "chunked" encoding (<a href="#transfer.codings" title="Transfer Codings">Section&nbsp;2.4</a>), a zero length chunk and empty trailer <em class="bcp14">MAY</em> be used to prematurely mark the end of the message. If the body was preceded by a Content-Length header, the client <em class="bcp14">MUST</em> close the connection.
     1447      </p>
     1448      <h3 id="rfc.section.6.2.3"><a href="#rfc.section.6.2.3">6.2.3</a>&nbsp;<a id="use.of.the.100.status" href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></h3>
     1449      <p id="rfc.section.6.2.3.p.1">The purpose of the 100 (Continue) status (see <a href="p2-semantics.html#status.100" title="100 Continue">Section 9.1.1</a> of <a href="#Part2" id="rfc.xref.Part2.13"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) is to allow a client that is sending a request message with a request body to determine if the origin server is willing
    14511450         to accept the request (based on the request headers) before the client sends the request body. In some cases, it might either
    14521451         be inappropriate or highly inefficient for the client to send the body if the server will reject the message without looking
    14531452         at the body.
    14541453      </p>
    1455       <p id="rfc.section.7.2.3.p.2">Requirements for HTTP/1.1 clients: </p>
     1454      <p id="rfc.section.6.2.3.p.2">Requirements for HTTP/1.1 clients: </p>
    14561455      <ul>
    14571456         <li>If a client will wait for a 100 (Continue) response before sending the request body, it <em class="bcp14">MUST</em> send an Expect request-header field (<a href="p2-semantics.html#header.expect" title="Expect">Section 10.2</a> of <a href="#Part2" id="rfc.xref.Part2.14"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) with the "100-continue" expectation.
     
    14601459         </li>
    14611460      </ul>
    1462       <p id="rfc.section.7.2.3.p.3">Because of the presence of older implementations, the protocol allows ambiguous situations in which a client may send "Expect:
     1461      <p id="rfc.section.6.2.3.p.3">Because of the presence of older implementations, the protocol allows ambiguous situations in which a client may send "Expect:
    14631462         100-continue" without receiving either a 417 (Expectation Failed) status or a 100 (Continue) status. Therefore, when a client
    14641463         sends this header field to an origin server (possibly via a proxy) from which it has never seen a 100 (Continue) status, the
    14651464         client <em class="bcp14">SHOULD NOT</em> wait for an indefinite period before sending the request body.
    14661465      </p>
    1467       <p id="rfc.section.7.2.3.p.4">Requirements for HTTP/1.1 origin servers: </p>
     1466      <p id="rfc.section.6.2.3.p.4">Requirements for HTTP/1.1 origin servers: </p>
    14681467      <ul>
    14691468         <li>Upon receiving a request which includes an Expect request-header field with the "100-continue" expectation, an origin server <em class="bcp14">MUST</em> either respond with 100 (Continue) status and continue to read from the input stream, or respond with a final status code.
     
    14891488         </li>
    14901489      </ul>
    1491       <p id="rfc.section.7.2.3.p.5">Requirements for HTTP/1.1 proxies: </p>
     1490      <p id="rfc.section.6.2.3.p.5">Requirements for HTTP/1.1 proxies: </p>
    14921491      <ul>
    14931492         <li>If a proxy receives a request that includes an Expect request-header field with the "100-continue" expectation, and the proxy
     
    15041503         </li>
    15051504      </ul>
    1506       <h3 id="rfc.section.7.2.4"><a href="#rfc.section.7.2.4">7.2.4</a>&nbsp;<a id="connection.premature" href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></h3>
    1507       <p id="rfc.section.7.2.4.p.1">If an HTTP/1.1 client sends a request which includes a request body, but which does not include an Expect request-header field
     1505      <h3 id="rfc.section.6.2.4"><a href="#rfc.section.6.2.4">6.2.4</a>&nbsp;<a id="connection.premature" href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></h3>
     1506      <p id="rfc.section.6.2.4.p.1">If an HTTP/1.1 client sends a request which includes a request body, but which does not include an Expect request-header field
    15081507         with the "100-continue" expectation, and if the client is not directly connected to an HTTP/1.1 origin server, and if the
    15091508         client sees the connection close before receiving any status from the server, the client <em class="bcp14">SHOULD</em> retry the request. If the client does retry this request, it <em class="bcp14">MAY</em> use the following "binary exponential backoff" algorithm to be assured of obtaining a reliable response:
     
    15221521         </li>
    15231522      </ol>
    1524       <p id="rfc.section.7.2.4.p.2">If at any point an error status is received, the client </p>
     1523      <p id="rfc.section.6.2.4.p.2">If at any point an error status is received, the client </p>
    15251524      <ul>
    15261525         <li><em class="bcp14">SHOULD NOT</em> continue and
     
    15291528         </li>
    15301529      </ul>
    1531       <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a id="header.fields" href="#header.fields">Header Field Definitions</a></h1>
    1532       <p id="rfc.section.8.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to message framing and transport protocols.</p>
    1533       <p id="rfc.section.8.p.2">For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who
     1530      <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="header.fields" href="#header.fields">Header Field Definitions</a></h1>
     1531      <p id="rfc.section.7.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to message framing and transport protocols.</p>
     1532      <p id="rfc.section.7.p.2">For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who
    15341533         receives the entity.
    15351534      </p>
    15361535      <div id="rfc.iref.c.1"></div>
    15371536      <div id="rfc.iref.h.3"></div>
    1538       <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a>&nbsp;<a id="header.connection" href="#header.connection">Connection</a></h2>
    1539       <p id="rfc.section.8.1.p.1">The general-header field "Connection" allows the sender to specify options that are desired for that particular connection
     1537      <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a id="header.connection" href="#header.connection">Connection</a></h2>
     1538      <p id="rfc.section.7.1.p.1">The general-header field "Connection" allows the sender to specify options that are desired for that particular connection
    15401539         and <em class="bcp14">MUST NOT</em> be communicated by proxies over further connections.
    15411540      </p>
    1542       <p id="rfc.section.8.1.p.2">The Connection header's value has the following grammar:</p>
     1541      <p id="rfc.section.7.1.p.2">The Connection header's value has the following grammar:</p>
    15431542      <div id="rfc.figure.u.42"></div><pre class="inline"><span id="rfc.iref.g.72"></span><span id="rfc.iref.g.73"></span><span id="rfc.iref.g.74"></span>  <a href="#header.connection" class="smpl">Connection</a>       = "Connection" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.connection" class="smpl">Connection-v</a>
    15441543  <a href="#header.connection" class="smpl">Connection-v</a>     = 1#<a href="#header.connection" class="smpl">connection-token</a>
    15451544  <a href="#header.connection" class="smpl">connection-token</a> = <a href="#rule.token.separators" class="smpl">token</a>
    1546 </pre><p id="rfc.section.8.1.p.4">HTTP/1.1 proxies <em class="bcp14">MUST</em> parse the Connection header field before a message is forwarded and, for each connection-token in this field, remove any header
     1545</pre><p id="rfc.section.7.1.p.4">HTTP/1.1 proxies <em class="bcp14">MUST</em> parse the Connection header field before a message is forwarded and, for each connection-token in this field, remove any header
    15471546         field(s) from the message with the same name as the connection-token. Connection options are signaled by the presence of a
    15481547         connection-token in the Connection header field, not by any corresponding additional header field(s), since the additional
    15491548         header field may not be sent if there are no parameters associated with that connection option.
    15501549      </p>
    1551       <p id="rfc.section.8.1.p.5">Message headers listed in the Connection header <em class="bcp14">MUST NOT</em> include end-to-end headers, such as Cache-Control.
    1552       </p>
    1553       <p id="rfc.section.8.1.p.6">HTTP/1.1 defines the "close" connection option for the sender to signal that the connection will be closed after completion
     1550      <p id="rfc.section.7.1.p.5">Message headers listed in the Connection header <em class="bcp14">MUST NOT</em> include end-to-end headers, such as Cache-Control.
     1551      </p>
     1552      <p id="rfc.section.7.1.p.6">HTTP/1.1 defines the "close" connection option for the sender to signal that the connection will be closed after completion
    15541553         of the response. For example,
    15551554      </p>
    15561555      <div id="rfc.figure.u.43"></div><pre class="text">  Connection: close
    1557 </pre><p id="rfc.section.8.1.p.8">in either the request or the response header fields indicates that the connection <em class="bcp14">SHOULD NOT</em> be considered `persistent' (<a href="#persistent.connections" title="Persistent Connections">Section&nbsp;7.1</a>) after the current request/response is complete.
    1558       </p>
    1559       <p id="rfc.section.8.1.p.9">An HTTP/1.1 client that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every request message.
    1560       </p>
    1561       <p id="rfc.section.8.1.p.10">An HTTP/1.1 server that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every response message that does not have a 1xx (informational) status code.
    1562       </p>
    1563       <p id="rfc.section.8.1.p.11">A system receiving an HTTP/1.0 (or lower-version) message that includes a Connection header <em class="bcp14">MUST</em>, for each connection-token in this field, remove and ignore any header field(s) from the message with the same name as the
     1556</pre><p id="rfc.section.7.1.p.8">in either the request or the response header fields indicates that the connection <em class="bcp14">SHOULD NOT</em> be considered `persistent' (<a href="#persistent.connections" title="Persistent Connections">Section&nbsp;6.1</a>) after the current request/response is complete.
     1557      </p>
     1558      <p id="rfc.section.7.1.p.9">An HTTP/1.1 client that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every request message.
     1559      </p>
     1560      <p id="rfc.section.7.1.p.10">An HTTP/1.1 server that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every response message that does not have a 1xx (informational) status code.
     1561      </p>
     1562      <p id="rfc.section.7.1.p.11">A system receiving an HTTP/1.0 (or lower-version) message that includes a Connection header <em class="bcp14">MUST</em>, for each connection-token in this field, remove and ignore any header field(s) from the message with the same name as the
    15641563         connection-token. This protects against mistaken forwarding of such header fields by pre-HTTP/1.1 proxies. See <a href="#compatibility.with.http.1.0.persistent.connections" title="Compatibility with HTTP/1.0 Persistent Connections">Appendix&nbsp;B.2</a>.
    15651564      </p>
    15661565      <div id="rfc.iref.c.2"></div>
    15671566      <div id="rfc.iref.h.4"></div>
    1568       <h2 id="rfc.section.8.2"><a href="#rfc.section.8.2">8.2</a>&nbsp;<a id="header.content-length" href="#header.content-length">Content-Length</a></h2>
    1569       <p id="rfc.section.8.2.p.1">The entity-header field "Content-Length" indicates the size of the entity-body, in decimal number of OCTETs, sent to the recipient
     1567      <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a>&nbsp;<a id="header.content-length" href="#header.content-length">Content-Length</a></h2>
     1568      <p id="rfc.section.7.2.p.1">The entity-header field "Content-Length" indicates the size of the entity-body, in decimal number of OCTETs, sent to the recipient
    15701569         or, in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET.
    15711570      </p>
    15721571      <div id="rfc.figure.u.44"></div><pre class="inline"><span id="rfc.iref.g.75"></span><span id="rfc.iref.g.76"></span>  <a href="#header.content-length" class="smpl">Content-Length</a>   = "Content-Length" ":" <a href="#rule.whitespace" class="smpl">OWS</a> 1*<a href="#header.content-length" class="smpl">Content-Length-v</a>
    15731572  <a href="#header.content-length" class="smpl">Content-Length-v</a> = 1*<a href="#core.rules" class="smpl">DIGIT</a>
    1574 </pre><p id="rfc.section.8.2.p.3">An example is</p>
     1573</pre><p id="rfc.section.7.2.p.3">An example is</p>
    15751574      <div id="rfc.figure.u.45"></div><pre class="text">  Content-Length: 3495
    1576 </pre><p id="rfc.section.8.2.p.5">Applications <em class="bcp14">SHOULD</em> use this field to indicate the transfer-length of the message-body, unless this is prohibited by the rules in <a href="#message.length" title="Message Length">Section&nbsp;4.4</a>.
    1577       </p>
    1578       <p id="rfc.section.8.2.p.6">Any Content-Length greater than or equal to zero is a valid value. <a href="#message.length" title="Message Length">Section&nbsp;4.4</a> describes how to determine the length of a message-body if a Content-Length is not given.
    1579       </p>
    1580       <p id="rfc.section.8.2.p.7">Note that the meaning of this field is significantly different from the corresponding definition in MIME, where it is an optional
     1575</pre><p id="rfc.section.7.2.p.5">Applications <em class="bcp14">SHOULD</em> use this field to indicate the transfer-length of the message-body, unless this is prohibited by the rules in <a href="#message.length" title="Message Length">Section&nbsp;3.4</a>.
     1576      </p>
     1577      <p id="rfc.section.7.2.p.6">Any Content-Length greater than or equal to zero is a valid value. <a href="#message.length" title="Message Length">Section&nbsp;3.4</a> describes how to determine the length of a message-body if a Content-Length is not given.
     1578      </p>
     1579      <p id="rfc.section.7.2.p.7">Note that the meaning of this field is significantly different from the corresponding definition in MIME, where it is an optional
    15811580         field used within the "message/external-body" content-type. In HTTP, it <em class="bcp14">SHOULD</em> be sent whenever the message's length can be determined prior to being transferred, unless this is prohibited by the rules
    1582          in <a href="#message.length" title="Message Length">Section&nbsp;4.4</a>.
     1581         in <a href="#message.length" title="Message Length">Section&nbsp;3.4</a>.
    15831582      </p>
    15841583      <div id="rfc.iref.d.1"></div>
    15851584      <div id="rfc.iref.h.5"></div>
    1586       <h2 id="rfc.section.8.3"><a href="#rfc.section.8.3">8.3</a>&nbsp;<a id="header.date" href="#header.date">Date</a></h2>
    1587       <p id="rfc.section.8.3.p.1">The general-header field "Date" represents the date and time at which the message was originated, having the same semantics
    1588          as orig-date 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.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as described in <a href="#full.date" title="Full Date">Section&nbsp;3.3.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.
     1585      <h2 id="rfc.section.7.3"><a href="#rfc.section.7.3">7.3</a>&nbsp;<a id="header.date" href="#header.date">Date</a></h2>
     1586      <p id="rfc.section.7.3.p.1">The general-header field "Date" represents the date and time at which the message was originated, having the same semantics
     1587         as orig-date 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.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as described in <a href="#full.date" title="Full Date">Section&nbsp;2.3.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.
    15891588      </p>
    15901589      <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.77"></span><span id="rfc.iref.g.78"></span>  <a href="#header.date" class="smpl">Date</a>   = "Date" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.date" class="smpl">Date-v</a>
    15911590  <a href="#header.date" class="smpl">Date-v</a> = <a href="#full.date" class="smpl">HTTP-date</a>
    1592 </pre><p id="rfc.section.8.3.p.3">An example is</p>
     1591</pre><p id="rfc.section.7.3.p.3">An example is</p>
    15931592      <div id="rfc.figure.u.47"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
    1594 </pre><p id="rfc.section.8.3.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
     1593</pre><p id="rfc.section.7.3.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
    15951594      </p>
    15961595      <ol>
     
    16001599            is inconvenient or impossible to generate a valid Date.
    16011600         </li>
    1602          <li>If the server does not have a clock that can provide a reasonable approximation of the current time, its responses <em class="bcp14">MUST NOT</em> include a Date header field. In this case, the rules in <a href="#clockless.origin.server.operation" title="Clockless Origin Server Operation">Section&nbsp;8.3.1</a>  <em class="bcp14">MUST</em> be followed.
     1601         <li>If the server does not have a clock that can provide a reasonable approximation of the current time, its responses <em class="bcp14">MUST NOT</em> include a Date header field. In this case, the rules in <a href="#clockless.origin.server.operation" title="Clockless Origin Server Operation">Section&nbsp;7.3.1</a>  <em class="bcp14">MUST</em> be followed.
    16031602         </li>
    16041603      </ol>
    1605       <p id="rfc.section.8.3.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient or gatewayed via a protocol which requires
     1604      <p id="rfc.section.7.3.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient or gatewayed via a protocol which requires
    16061605         a Date. An HTTP implementation without a clock <em class="bcp14">MUST NOT</em> cache responses without revalidating them on every use. An HTTP cache, especially a shared cache, <em class="bcp14">SHOULD</em> use a mechanism, such as NTP <a href="#RFC1305" id="rfc.xref.RFC1305.1"><cite title="Network Time Protocol (Version 3) Specification, Implementation">[RFC1305]</cite></a>, to synchronize its clock with a reliable external standard.
    16071606      </p>
    1608       <p id="rfc.section.8.3.p.7">Clients <em class="bcp14">SHOULD</em> only send a Date header field in messages that include an entity-body, as in the case of the PUT and POST requests, and even
     1607      <p id="rfc.section.7.3.p.7">Clients <em class="bcp14">SHOULD</em> only send a Date header field in messages that include an entity-body, as in the case of the PUT and POST requests, and even
    16091608         then it is optional. A client without a clock <em class="bcp14">MUST NOT</em> send a Date header field in a request.
    16101609      </p>
    1611       <p id="rfc.section.8.3.p.8">The HTTP-date sent in a Date header <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means
     1610      <p id="rfc.section.7.3.p.8">The HTTP-date sent in a Date header <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means
    16121611         of generating a reasonably accurate date and time. In theory, the date ought to represent the moment just before the entity
    16131612         is generated. In practice, the date can be generated at any time during the message origination without affecting its semantic
    16141613         value.
    16151614      </p>
    1616       <h3 id="rfc.section.8.3.1"><a href="#rfc.section.8.3.1">8.3.1</a>&nbsp;<a id="clockless.origin.server.operation" href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></h3>
    1617       <p id="rfc.section.8.3.1.p.1">Some origin server implementations might not have a clock available. An origin server without a clock <em class="bcp14">MUST NOT</em> assign Expires or Last-Modified values to a response, unless these values were associated with the resource by a system or
     1615      <h3 id="rfc.section.7.3.1"><a href="#rfc.section.7.3.1">7.3.1</a>&nbsp;<a id="clockless.origin.server.operation" href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></h3>
     1616      <p id="rfc.section.7.3.1.p.1">Some origin server implementations might not have a clock available. An origin server without a clock <em class="bcp14">MUST NOT</em> assign Expires or Last-Modified values to a response, unless these values were associated with the resource by a system or
    16181617         user with a reliable clock. It <em class="bcp14">MAY</em> assign an Expires value that is known, at or before server configuration time, to be in the past (this allows "pre-expiration"
    16191618         of responses without storing separate Expires values for each resource).
     
    16211620      <div id="rfc.iref.h.6"></div>
    16221621      <div id="rfc.iref.h.7"></div>
    1623       <h2 id="rfc.section.8.4"><a href="#rfc.section.8.4">8.4</a>&nbsp;<a id="header.host" href="#header.host">Host</a></h2>
    1624       <p id="rfc.section.8.4.p.1">The request-header field "Host" specifies the Internet host and port number of the resource being requested, as obtained from
    1625          the original URI given by the user or referring resource (generally an HTTP URL, as described in <a href="#http.uri" title="http URI scheme">Section&nbsp;3.2.1</a>). The Host field value <em class="bcp14">MUST</em> represent the naming authority of the origin server or gateway given by the original URL. This allows the origin server or
     1622      <h2 id="rfc.section.7.4"><a href="#rfc.section.7.4">7.4</a>&nbsp;<a id="header.host" href="#header.host">Host</a></h2>
     1623      <p id="rfc.section.7.4.p.1">The request-header field "Host" specifies the Internet host and port number of the resource being requested, as obtained from
     1624         the original URI given by the user or referring resource (generally an HTTP URL, as described in <a href="#http.uri" title="http URI scheme">Section&nbsp;2.2.1</a>). The Host field value <em class="bcp14">MUST</em> represent the naming authority of the origin server or gateway given by the original URL. This allows the origin server or
    16261625         gateway to differentiate between internally-ambiguous URLs, such as the root "/" URL of a server for multiple host names on
    16271626         a single IP address.
    16281627      </p>
    16291628      <div id="rfc.figure.u.48"></div><pre class="inline"><span id="rfc.iref.g.79"></span><span id="rfc.iref.g.80"></span>  <a href="#header.host" class="smpl">Host</a>   = "Host" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.host" class="smpl">Host-v</a>
    1630   <a href="#header.host" class="smpl">Host-v</a> = <a href="#uri" class="smpl">uri-host</a> [ ":" <a href="#uri" class="smpl">port</a> ] ; <a href="#http.uri" title="http URI scheme">Section&nbsp;3.2.1</a>
    1631 </pre><p id="rfc.section.8.4.p.3">A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an HTTP
     1629  <a href="#header.host" class="smpl">Host-v</a> = <a href="#uri" class="smpl">uri-host</a> [ ":" <a href="#uri" class="smpl">port</a> ] ; <a href="#http.uri" title="http URI scheme">Section&nbsp;2.2.1</a>
     1630</pre><p id="rfc.section.7.4.p.3">A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an HTTP
    16321631         URL). For example, a request on the origin server for &lt;http://www.example.org/pub/WWW/&gt; would properly include:
    16331632      </p>
    16341633      <div id="rfc.figure.u.49"></div><pre class="text">  GET /pub/WWW/ HTTP/1.1
    16351634  Host: www.example.org
    1636 </pre><p id="rfc.section.8.4.p.5">A client <em class="bcp14">MUST</em> include a Host header field in all HTTP/1.1 request messages. If the requested URI does not include an Internet host name
     1635</pre><p id="rfc.section.7.4.p.5">A client <em class="bcp14">MUST</em> include a Host header field in all HTTP/1.1 request messages. If the requested URI does not include an Internet host name
    16371636         for the service being requested, then the Host header field <em class="bcp14">MUST</em> be given with an empty value. An HTTP/1.1 proxy <em class="bcp14">MUST</em> ensure that any request message it forwards does contain an appropriate Host header field that identifies the service being
    16381637         requested by the proxy. All Internet-based HTTP/1.1 servers <em class="bcp14">MUST</em> respond with a 400 (Bad Request) status code to any HTTP/1.1 request message which lacks a Host header field.
    16391638      </p>
    1640       <p id="rfc.section.8.4.p.6">See Sections <a href="#the.resource.identified.by.a.request" title="The Resource Identified by a Request">5.2</a> and <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">B.1.1</a> for other requirements relating to Host.
     1639      <p id="rfc.section.7.4.p.6">See Sections <a href="#the.resource.identified.by.a.request" title="The Resource Identified by a Request">4.2</a> and <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">B.1.1</a> for other requirements relating to Host.
    16411640      </p>
    16421641      <div id="rfc.iref.t.1"></div>
    16431642      <div id="rfc.iref.h.8"></div>
    1644       <h2 id="rfc.section.8.5"><a href="#rfc.section.8.5">8.5</a>&nbsp;<a id="header.te" href="#header.te">TE</a></h2>
    1645       <p id="rfc.section.8.5.p.1">The request-header field "TE" indicates what extension transfer-codings it is willing to accept in the response and whether
     1643      <h2 id="rfc.section.7.5"><a href="#rfc.section.7.5">7.5</a>&nbsp;<a id="header.te" href="#header.te">TE</a></h2>
     1644      <p id="rfc.section.7.5.p.1">The request-header field "TE" indicates what extension transfer-codings it is willing to accept in the response and whether
    16461645         or not it is willing to accept trailer fields in a chunked transfer-coding. Its value may consist of the keyword "trailers"
    1647          and/or a comma-separated list of extension transfer-coding names with optional accept parameters (as described in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.4</a>).
     1646         and/or a comma-separated list of extension transfer-coding names with optional accept parameters (as described in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;2.4</a>).
    16481647      </p>
    16491648      <div id="rfc.figure.u.50"></div><pre class="inline"><span id="rfc.iref.g.81"></span><span id="rfc.iref.g.82"></span><span id="rfc.iref.g.83"></span>  <a href="#header.te" class="smpl">TE</a>        = "TE" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.te" class="smpl">TE-v</a>
    16501649  <a href="#header.te" class="smpl">TE-v</a>      = #<a href="#header.te" class="smpl">t-codings</a>
    16511650  <a href="#header.te" class="smpl">t-codings</a> = "trailers" / ( <a href="#transfer.codings" class="smpl">transfer-extension</a> [ <a href="#abnf.dependencies" class="smpl">accept-params</a> ] )
    1652 </pre><p id="rfc.section.8.5.p.3">The presence of the keyword "trailers" indicates that the client is willing to accept trailer fields in a chunked transfer-coding,
    1653          as defined in <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;3.4.1</a>. This keyword is reserved for use with transfer-coding values even though it does not itself represent a transfer-coding.
    1654       </p>
    1655       <p id="rfc.section.8.5.p.4">Examples of its use are:</p>
     1651</pre><p id="rfc.section.7.5.p.3">The presence of the keyword "trailers" indicates that the client is willing to accept trailer fields in a chunked transfer-coding,
     1652         as defined in <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;2.4.1</a>. This keyword is reserved for use with transfer-coding values even though it does not itself represent a transfer-coding.
     1653      </p>
     1654      <p id="rfc.section.7.5.p.4">Examples of its use are:</p>
    16561655      <div id="rfc.figure.u.51"></div><pre class="text">  TE: deflate
    16571656  TE:
    16581657  TE: trailers, deflate;q=0.5
    1659 </pre><p id="rfc.section.8.5.p.6">The TE header field only applies to the immediate connection. Therefore, the keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.4" title="Connection">Section&nbsp;8.1</a>) whenever TE is present in an HTTP/1.1 message.
    1660       </p>
    1661       <p id="rfc.section.8.5.p.7">A server tests whether a transfer-coding is acceptable, according to a TE field, using these rules: </p>
     1658</pre><p id="rfc.section.7.5.p.6">The TE header field only applies to the immediate connection. Therefore, the keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.4" title="Connection">Section&nbsp;7.1</a>) whenever TE is present in an HTTP/1.1 message.
     1659      </p>
     1660      <p id="rfc.section.7.5.p.7">A server tests whether a transfer-coding is acceptable, according to a TE field, using these rules: </p>
    16621661      <ol>
    16631662         <li>
     
    16821681         </li>
    16831682      </ol>
    1684       <p id="rfc.section.8.5.p.8">If the TE field-value is empty or if no TE field is present, the only transfer-coding is "chunked". A message with no transfer-coding
     1683      <p id="rfc.section.7.5.p.8">If the TE field-value is empty or if no TE field is present, the only transfer-coding is "chunked". A message with no transfer-coding
    16851684         is always acceptable.
    16861685      </p>
    16871686      <div id="rfc.iref.t.2"></div>
    16881687      <div id="rfc.iref.h.9"></div>
    1689       <h2 id="rfc.section.8.6"><a href="#rfc.section.8.6">8.6</a>&nbsp;<a id="header.trailer" href="#header.trailer">Trailer</a></h2>
    1690       <p id="rfc.section.8.6.p.1">The general field "Trailer" indicates that the given set of header fields is present in the trailer of a message encoded with
     1688      <h2 id="rfc.section.7.6"><a href="#rfc.section.7.6">7.6</a>&nbsp;<a id="header.trailer" href="#header.trailer">Trailer</a></h2>
     1689      <p id="rfc.section.7.6.p.1">The general field "Trailer" indicates that the given set of header fields is present in the trailer of a message encoded with
    16911690         chunked transfer-coding.
    16921691      </p>
    16931692      <div id="rfc.figure.u.52"></div><pre class="inline"><span id="rfc.iref.g.84"></span><span id="rfc.iref.g.85"></span>  <a href="#header.trailer" class="smpl">Trailer</a>   = "Trailer" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.trailer" class="smpl">Trailer-v</a>
    16941693  <a href="#header.trailer" class="smpl">Trailer-v</a> = 1#<a href="#message.headers" class="smpl">field-name</a>
    1695 </pre><p id="rfc.section.8.6.p.3">An HTTP/1.1 message <em class="bcp14">SHOULD</em> include a Trailer header field in a message using chunked transfer-coding with a non-empty trailer. Doing so allows the recipient
     1694</pre><p id="rfc.section.7.6.p.3">An HTTP/1.1 message <em class="bcp14">SHOULD</em> include a Trailer header field in a message using chunked transfer-coding with a non-empty trailer. Doing so allows the recipient
    16961695         to know which header fields to expect in the trailer.
    16971696      </p>
    1698       <p id="rfc.section.8.6.p.4">If no Trailer header field is present, the trailer <em class="bcp14">SHOULD NOT</em> include any header fields. See <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;3.4.1</a> for restrictions on the use of trailer fields in a "chunked" transfer-coding.
    1699       </p>
    1700       <p id="rfc.section.8.6.p.5">Message header fields listed in the Trailer header field <em class="bcp14">MUST NOT</em> include the following header fields:
     1697      <p id="rfc.section.7.6.p.4">If no Trailer header field is present, the trailer <em class="bcp14">SHOULD NOT</em> include any header fields. See <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;2.4.1</a> for restrictions on the use of trailer fields in a "chunked" transfer-coding.
     1698      </p>
     1699      <p id="rfc.section.7.6.p.5">Message header fields listed in the Trailer header field <em class="bcp14">MUST NOT</em> include the following header fields:
    17011700      </p>
    17021701      <ul>
     
    17071706      <div id="rfc.iref.t.3"></div>
    17081707      <div id="rfc.iref.h.10"></div>
    1709       <h2 id="rfc.section.8.7"><a href="#rfc.section.8.7">8.7</a>&nbsp;<a id="header.transfer-encoding" href="#header.transfer-encoding">Transfer-Encoding</a></h2>
    1710       <p id="rfc.section.8.7.p.1">The general-header "Transfer-Encoding" field indicates what (if any) type of transformation has been applied to the message
     1708      <h2 id="rfc.section.7.7"><a href="#rfc.section.7.7">7.7</a>&nbsp;<a id="header.transfer-encoding" href="#header.transfer-encoding">Transfer-Encoding</a></h2>
     1709      <p id="rfc.section.7.7.p.1">The general-header "Transfer-Encoding" field indicates what (if any) type of transformation has been applied to the message
    17111710         body in order to safely transfer it between the sender and the recipient. This differs from the content-coding in that the
    17121711         transfer-coding is a property of the message, not of the entity.
     
    17151714                        <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding-v</a>
    17161715  <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding-v</a> = 1#<a href="#transfer.codings" class="smpl">transfer-coding</a>
    1717 </pre><p id="rfc.section.8.7.p.3">Transfer-codings are defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.4</a>. An example is:
     1716</pre><p id="rfc.section.7.7.p.3">Transfer-codings are defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;2.4</a>. An example is:
    17181717      </p>
    17191718      <div id="rfc.figure.u.54"></div><pre class="text">  Transfer-Encoding: chunked
    1720 </pre><p id="rfc.section.8.7.p.5">If multiple encodings have been applied to an entity, the transfer-codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other entity-header fields not defined by this specification.
    1721       </p>
    1722       <p id="rfc.section.8.7.p.6">Many older HTTP/1.0 applications do not understand the Transfer-Encoding header.</p>
     1719</pre><p id="rfc.section.7.7.p.5">If multiple encodings have been applied to an entity, the transfer-codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other entity-header fields not defined by this specification.
     1720      </p>
     1721      <p id="rfc.section.7.7.p.6">Many older HTTP/1.0 applications do not understand the Transfer-Encoding header.</p>
    17231722      <div id="rfc.iref.u.3"></div>
    17241723      <div id="rfc.iref.h.11"></div>
    1725       <h2 id="rfc.section.8.8"><a href="#rfc.section.8.8">8.8</a>&nbsp;<a id="header.upgrade" href="#header.upgrade">Upgrade</a></h2>
    1726       <p id="rfc.section.8.8.p.1">The general-header "Upgrade" allows the client to specify what additional communication protocols it supports and would like
     1724      <h2 id="rfc.section.7.8"><a href="#rfc.section.7.8">7.8</a>&nbsp;<a id="header.upgrade" href="#header.upgrade">Upgrade</a></h2>
     1725      <p id="rfc.section.7.8.p.1">The general-header "Upgrade" allows the client to specify what additional communication protocols it supports and would like
    17271726         to use if the server finds it appropriate to switch protocols. The server <em class="bcp14">MUST</em> use the Upgrade header field within a 101 (Switching Protocols) response to indicate which protocol(s) are being switched.
    17281727      </p>
    17291728      <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.88"></span><span id="rfc.iref.g.89"></span>  <a href="#header.upgrade" class="smpl">Upgrade</a>   = "Upgrade" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.upgrade" class="smpl">Upgrade-v</a>
    17301729  <a href="#header.upgrade" class="smpl">Upgrade-v</a> = 1#<a href="#product.tokens" class="smpl">product</a>
    1731 </pre><p id="rfc.section.8.8.p.3">For example,</p>
     1730</pre><p id="rfc.section.7.8.p.3">For example,</p>
    17321731      <div id="rfc.figure.u.56"></div><pre class="text">  Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
    1733 </pre><p id="rfc.section.8.8.p.5">The Upgrade header field is intended to provide a simple mechanism for transition from HTTP/1.1 to some other, incompatible
     1732</pre><p id="rfc.section.7.8.p.5">The Upgrade header field is intended to provide a simple mechanism for transition from HTTP/1.1 to some other, incompatible
    17341733         protocol. It does so by allowing the client to advertise its desire to use another protocol, such as a later version of HTTP
    17351734         with a higher major version number, even though the current request has been made using HTTP/1.1. This eases the difficult
     
    17381737         the server, possibly according to the nature of the method and/or resource being requested).
    17391738      </p>
    1740       <p id="rfc.section.8.8.p.6">The Upgrade header field only applies to switching application-layer protocols upon the existing transport-layer connection.
     1739      <p id="rfc.section.7.8.p.6">The Upgrade header field only applies to switching application-layer protocols upon the existing transport-layer connection.
    17411740         Upgrade cannot be used to insist on a protocol change; its acceptance and use by the server is optional. The capabilities
    17421741         and nature of the application-layer communication after the protocol change is entirely dependent upon the new protocol chosen,
    17431742         although the first action after changing the protocol <em class="bcp14">MUST</em> be a response to the initial HTTP request containing the Upgrade header field.
    17441743      </p>
    1745       <p id="rfc.section.8.8.p.7">The Upgrade header field only applies to the immediate connection. Therefore, the upgrade keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.5" title="Connection">Section&nbsp;8.1</a>) whenever Upgrade is present in an HTTP/1.1 message.
    1746       </p>
    1747       <p id="rfc.section.8.8.p.8">The Upgrade header field cannot be used to indicate a switch to a protocol on a different connection. For that purpose, it
     1744      <p id="rfc.section.7.8.p.7">The Upgrade header field only applies to the immediate connection. Therefore, the upgrade keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.5" title="Connection">Section&nbsp;7.1</a>) whenever Upgrade is present in an HTTP/1.1 message.
     1745      </p>
     1746      <p id="rfc.section.7.8.p.8">The Upgrade header field cannot be used to indicate a switch to a protocol on a different connection. For that purpose, it
    17481747         is more appropriate to use a 301, 302, 303, or 305 redirection response.
    17491748      </p>
    1750       <p id="rfc.section.8.8.p.9">This specification only defines the protocol name "HTTP" for use by the family of Hypertext Transfer Protocols, as defined
    1751          by the HTTP version rules of <a href="#http.version" title="HTTP Version">Section&nbsp;3.1</a> and future updates to this specification. Any token can be used as a protocol name; however, it will only be useful if both
     1749      <p id="rfc.section.7.8.p.9">This specification only defines the protocol name "HTTP" for use by the family of Hypertext Transfer Protocols, as defined
     1750         by the HTTP version rules of <a href="#http.version" title="HTTP Version">Section&nbsp;2.1</a> and future updates to this specification. Any token can be used as a protocol name; however, it will only be useful if both
    17521751         the client and server associate the name with the same protocol.
    17531752      </p>
    17541753      <div id="rfc.iref.v.1"></div>
    17551754      <div id="rfc.iref.h.12"></div>
    1756       <h2 id="rfc.section.8.9"><a href="#rfc.section.8.9">8.9</a>&nbsp;<a id="header.via" href="#header.via">Via</a></h2>
    1757       <p id="rfc.section.8.9.p.1">The general-header field "Via" <em class="bcp14">MUST</em> be used by gateways and proxies to indicate the intermediate protocols and recipients between the user agent and the server
     1755      <h2 id="rfc.section.7.9"><a href="#rfc.section.7.9">7.9</a>&nbsp;<a id="header.via" href="#header.via">Via</a></h2>
     1756      <p id="rfc.section.7.9.p.1">The general-header field "Via" <em class="bcp14">MUST</em> be used by gateways and proxies to indicate the intermediate protocols and recipients between the user agent and the server
    17581757         on requests, and between the origin server and the client on responses. It is analogous to the "Received" field defined in <a href="http://tools.ietf.org/html/rfc5322#section-3.6.7">Section 3.6.7</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.5"><cite title="Internet Message Format">[RFC5322]</cite></a> and is intended to be used for tracking message forwards, avoiding request loops, and identifying the protocol capabilities
    17591758         of all senders along the request/response chain.
     
    17671766  <a href="#header.via" class="smpl">received-by</a>       = ( <a href="#uri" class="smpl">uri-host</a> [ ":" <a href="#uri" class="smpl">port</a> ] ) / <a href="#header.via" class="smpl">pseudonym</a>
    17681767  <a href="#header.via" class="smpl">pseudonym</a>         = <a href="#rule.token.separators" class="smpl">token</a>
    1769 </pre><p id="rfc.section.8.9.p.3">The received-protocol indicates the protocol version of the message received by the server or client along each segment of
     1768</pre><p id="rfc.section.7.9.p.3">The received-protocol indicates the protocol version of the message received by the server or client along each segment of
    17701769         the request/response chain. The received-protocol version is appended to the Via field value when the message is forwarded
    17711770         so that information about the protocol capabilities of upstream applications remains visible to all recipients.
    17721771      </p>
    1773       <p id="rfc.section.8.9.p.4">The protocol-name is optional if and only if it would be "HTTP". The received-by field is normally the host and optional port
     1772      <p id="rfc.section.7.9.p.4">The protocol-name is optional if and only if it would be "HTTP". The received-by field is normally the host and optional port
    17741773         number of a recipient server or client that subsequently forwarded the message. However, if the real host is considered to
    17751774         be sensitive information, it <em class="bcp14">MAY</em> be replaced by a pseudonym. If the port is not given, it <em class="bcp14">MAY</em> be assumed to be the default port of the received-protocol.
    17761775      </p>
    1777       <p id="rfc.section.8.9.p.5">Multiple Via field values represents each proxy or gateway that has forwarded the message. Each recipient <em class="bcp14">MUST</em> append its information such that the end result is ordered according to the sequence of forwarding applications.
    1778       </p>
    1779       <p id="rfc.section.8.9.p.6">Comments <em class="bcp14">MAY</em> be used in the Via header field to identify the software of the recipient proxy or gateway, analogous to the User-Agent and
     1776      <p id="rfc.section.7.9.p.5">Multiple Via field values represents each proxy or gateway that has forwarded the message. Each recipient <em class="bcp14">MUST</em> append its information such that the end result is ordered according to the sequence of forwarding applications.
     1777      </p>
     1778      <p id="rfc.section.7.9.p.6">Comments <em class="bcp14">MAY</em> be used in the Via header field to identify the software of the recipient proxy or gateway, analogous to the User-Agent and
    17801779         Server header fields. However, all comments in the Via field are optional and <em class="bcp14">MAY</em> be removed by any recipient prior to forwarding the message.
    17811780      </p>
    1782       <p id="rfc.section.8.9.p.7">For example, a request message could be sent from an HTTP/1.0 user agent to an internal proxy code-named "fred", which uses
     1781      <p id="rfc.section.7.9.p.7">For example, a request message could be sent from an HTTP/1.0 user agent to an internal proxy code-named "fred", which uses
    17831782         HTTP/1.1 to forward the request to a public proxy at p.example.net, which completes the request by forwarding it to the origin
    17841783         server at www.example.com. The request received by www.example.com would then have the following Via header field:
    17851784      </p>
    17861785      <div id="rfc.figure.u.58"></div><pre class="text">  Via: 1.0 fred, 1.1 p.example.net (Apache/1.1)
    1787 </pre><p id="rfc.section.8.9.p.9">Proxies and gateways used as a portal through a network firewall <em class="bcp14">SHOULD NOT</em>, by default, forward the names and ports of hosts within the firewall region. This information <em class="bcp14">SHOULD</em> only be propagated if explicitly enabled. If not enabled, the received-by host of any host behind the firewall <em class="bcp14">SHOULD</em> be replaced by an appropriate pseudonym for that host.
    1788       </p>
    1789       <p id="rfc.section.8.9.p.10">For organizations that have strong privacy requirements for hiding internal structures, a proxy <em class="bcp14">MAY</em> combine an ordered subsequence of Via header field entries with identical received-protocol values into a single such entry.
     1786</pre><p id="rfc.section.7.9.p.9">Proxies and gateways used as a portal through a network firewall <em class="bcp14">SHOULD NOT</em>, by default, forward the names and ports of hosts within the firewall region. This information <em class="bcp14">SHOULD</em> only be propagated if explicitly enabled. If not enabled, the received-by host of any host behind the firewall <em class="bcp14">SHOULD</em> be replaced by an appropriate pseudonym for that host.
     1787      </p>
     1788      <p id="rfc.section.7.9.p.10">For organizations that have strong privacy requirements for hiding internal structures, a proxy <em class="bcp14">MAY</em> combine an ordered subsequence of Via header field entries with identical received-protocol values into a single such entry.
    17901789         For example,
    17911790      </p>
    17921791      <div id="rfc.figure.u.59"></div><pre class="text">  Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy
    1793 </pre><p id="rfc.section.8.9.p.12">could be collapsed to</p>
     1792</pre><p id="rfc.section.7.9.p.12">could be collapsed to</p>
    17941793      <div id="rfc.figure.u.60"></div><pre class="text">  Via: 1.0 ricky, 1.1 mertz, 1.0 lucy
    1795 </pre><p id="rfc.section.8.9.p.14">Applications <em class="bcp14">SHOULD NOT</em> combine multiple entries unless they are all under the same organizational control and the hosts have already been replaced
     1794</pre><p id="rfc.section.7.9.p.14">Applications <em class="bcp14">SHOULD NOT</em> combine multiple entries unless they are all under the same organizational control and the hosts have already been replaced
    17961795         by pseudonyms. Applications <em class="bcp14">MUST NOT</em> combine entries which have different received-protocol values.
    17971796      </p>
    1798       <h1 id="rfc.section.9"><a href="#rfc.section.9">9.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
    1799       <h2 id="rfc.section.9.1"><a href="#rfc.section.9.1">9.1</a>&nbsp;<a id="message.header.registration" href="#message.header.registration">Message Header Registration</a></h2>
    1800       <p id="rfc.section.9.1.p.1">The Message Header 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; should be updated with the permanent registrations below (see <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>):
     1797      <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
     1798      <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a>&nbsp;<a id="message.header.registration" href="#message.header.registration">Message Header Registration</a></h2>
     1799      <p id="rfc.section.8.1.p.1">The Message Header 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; should be updated with the permanent registrations below (see <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>):
    18011800      </p>
    18021801      <div id="rfc.table.1">
     
    18161815                  <td>http</td>
    18171816                  <td>standard</td>
    1818                   <td> <a href="#header.connection" id="rfc.xref.header.connection.6" title="Connection">Section&nbsp;8.1</a>
     1817                  <td> <a href="#header.connection" id="rfc.xref.header.connection.6" title="Connection">Section&nbsp;7.1</a>
    18191818                  </td>
    18201819               </tr>
     
    18231822                  <td>http</td>
    18241823                  <td>standard</td>
    1825                   <td> <a href="#header.content-length" id="rfc.xref.header.content-length.2" title="Content-Length">Section&nbsp;8.2</a>
     1824                  <td> <a href="#header.content-length" id="rfc.xref.header.content-length.2" title="Content-Length">Section&nbsp;7.2</a>
    18261825                  </td>
    18271826               </tr>
     
    18301829                  <td>http</td>
    18311830                  <td>standard</td>
    1832                   <td> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;8.3</a>
     1831                  <td> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;7.3</a>
    18331832                  </td>
    18341833               </tr>
     
    18371836                  <td>http</td>
    18381837                  <td>standard</td>
    1839                   <td> <a href="#header.host" id="rfc.xref.header.host.1" title="Host">Section&nbsp;8.4</a>
     1838                  <td> <a href="#header.host" id="rfc.xref.header.host.1" title="Host">Section&nbsp;7.4</a>
    18401839                  </td>
    18411840               </tr>
     
    18441843                  <td>http</td>
    18451844                  <td>standard</td>
    1846                   <td> <a href="#header.te" id="rfc.xref.header.te.3" title="TE">Section&nbsp;8.5</a>
     1845                  <td> <a href="#header.te" id="rfc.xref.header.te.3" title="TE">Section&nbsp;7.5</a>
    18471846                  </td>
    18481847               </tr>
     
    18511850                  <td>http</td>
    18521851                  <td>standard</td>
    1853                   <td> <a href="#header.trailer" id="rfc.xref.header.trailer.3" title="Trailer">Section&nbsp;8.6</a>
     1852                  <td> <a href="#header.trailer" id="rfc.xref.header.trailer.3" title="Trailer">Section&nbsp;7.6</a>
    18541853                  </td>
    18551854               </tr>
     
    18581857                  <td>http</td>
    18591858                  <td>standard</td>
    1860                   <td> <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.5" title="Transfer-Encoding">Section&nbsp;8.7</a>
     1859                  <td> <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.5" title="Transfer-Encoding">Section&nbsp;7.7</a>
    18611860                  </td>
    18621861               </tr>
     
    18651864                  <td>http</td>
    18661865                  <td>standard</td>
    1867                   <td> <a href="#header.upgrade" id="rfc.xref.header.upgrade.2" title="Upgrade">Section&nbsp;8.8</a>
     1866                  <td> <a href="#header.upgrade" id="rfc.xref.header.upgrade.2" title="Upgrade">Section&nbsp;7.8</a>
    18681867                  </td>
    18691868               </tr>
     
    18721871                  <td>http</td>
    18731872                  <td>standard</td>
    1874                   <td> <a href="#header.via" id="rfc.xref.header.via.2" title="Via">Section&nbsp;8.9</a>
     1873                  <td> <a href="#header.via" id="rfc.xref.header.via.2" title="Via">Section&nbsp;7.9</a>
    18751874                  </td>
    18761875               </tr>
     
    18781877         </table>
    18791878      </div>
    1880       <p id="rfc.section.9.1.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
    1881       <h2 id="rfc.section.9.2"><a href="#rfc.section.9.2">9.2</a>&nbsp;<a id="uri.scheme.registration" href="#uri.scheme.registration">URI Scheme Registration</a></h2>
    1882       <p id="rfc.section.9.2.p.1">The entry for the "http" URI Scheme in the registry located at &lt;<a href="http://www.iana.org/assignments/uri-schemes.html">http://www.iana.org/assignments/uri-schemes.html</a>&gt; should be updated to point to <a href="#http.uri" title="http URI scheme">Section&nbsp;3.2.1</a> of this document (see <a href="#RFC4395" id="rfc.xref.RFC4395.1"><cite title="Guidelines and Registration Procedures for New URI Schemes">[RFC4395]</cite></a>).
    1883       </p>
    1884       <h2 id="rfc.section.9.3"><a href="#rfc.section.9.3">9.3</a>&nbsp;<a id="internet.media.type.http" href="#internet.media.type.http">Internet Media Type Registrations</a></h2>
    1885       <p id="rfc.section.9.3.p.1">This document serves as the specification for the Internet media types "message/http" and "application/http". The following
     1879      <p id="rfc.section.8.1.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
     1880      <h2 id="rfc.section.8.2"><a href="#rfc.section.8.2">8.2</a>&nbsp;<a id="uri.scheme.registration" href="#uri.scheme.registration">URI Scheme Registration</a></h2>
     1881      <p id="rfc.section.8.2.p.1">The entry for the "http" URI Scheme in the registry located at &lt;<a href="http://www.iana.org/assignments/uri-schemes.html">http://www.iana.org/assignments/uri-schemes.html</a>&gt; should be updated to point to <a href="#http.uri" title="http URI scheme">Section&nbsp;2.2.1</a> of this document (see <a href="#RFC4395" id="rfc.xref.RFC4395.1"><cite title="Guidelines and Registration Procedures for New URI Schemes">[RFC4395]</cite></a>).
     1882      </p>
     1883      <h2 id="rfc.section.8.3"><a href="#rfc.section.8.3">8.3</a>&nbsp;<a id="internet.media.type.http" href="#internet.media.type.http">Internet Media Type Registrations</a></h2>
     1884      <p id="rfc.section.8.3.p.1">This document serves as the specification for the Internet media types "message/http" and "application/http". The following
    18861885         is to be registered with IANA (see <a href="#RFC4288" id="rfc.xref.RFC4288.1"><cite title="Media Type Specifications and Registration Procedures">[RFC4288]</cite></a>).
    18871886      </p>
    18881887      <div id="rfc.iref.m.1"></div>
    18891888      <div id="rfc.iref.m.2"></div>
    1890       <h3 id="rfc.section.9.3.1"><a href="#rfc.section.9.3.1">9.3.1</a>&nbsp;<a id="internet.media.type.message.http" href="#internet.media.type.message.http">Internet Media Type message/http</a></h3>
    1891       <p id="rfc.section.9.3.1.p.1">The message/http type can be used to enclose a single HTTP request or response message, provided that it obeys the MIME restrictions
     1889      <h3 id="rfc.section.8.3.1"><a href="#rfc.section.8.3.1">8.3.1</a>&nbsp;<a id="internet.media.type.message.http" href="#internet.media.type.message.http">Internet Media Type message/http</a></h3>
     1890      <p id="rfc.section.8.3.1.p.1">The message/http type can be used to enclose a single HTTP request or response message, provided that it obeys the MIME restrictions
    18921891         for all "message" types regarding line length and encodings.
    18931892      </p>
    1894       <p id="rfc.section.9.3.1.p.2"> </p>
     1893      <p id="rfc.section.8.3.1.p.2"> </p>
    18951894      <dl>
    18961895         <dt>Type name:</dt>
     
    19181917         <dd>none</dd>
    19191918         <dt>Published specification:</dt>
    1920          <dd>This specification (see <a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section&nbsp;9.3.1</a>).
     1919         <dd>This specification (see <a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section&nbsp;8.3.1</a>).
    19211920         </dd>
    19221921         <dt>Applications that use this media type:</dt>
     
    19431942      <div id="rfc.iref.m.3"></div>
    19441943      <div id="rfc.iref.a.1"></div>
    1945       <h3 id="rfc.section.9.3.2"><a href="#rfc.section.9.3.2">9.3.2</a>&nbsp;<a id="internet.media.type.application.http" href="#internet.media.type.application.http">Internet Media Type application/http</a></h3>
    1946       <p id="rfc.section.9.3.2.p.1">The application/http type can be used to enclose a pipeline of one or more HTTP request or response messages (not intermixed).</p>
    1947       <p id="rfc.section.9.3.2.p.2"> </p>
     1944      <h3 id="rfc.section.8.3.2"><a href="#rfc.section.8.3.2">8.3.2</a>&nbsp;<a id="internet.media.type.application.http" href="#internet.media.type.application.http">Internet Media Type application/http</a></h3>
     1945      <p id="rfc.section.8.3.2.p.1">The application/http type can be used to enclose a pipeline of one or more HTTP request or response messages (not intermixed).</p>
     1946      <p id="rfc.section.8.3.2.p.2"> </p>
    19481947      <dl>
    19491948         <dt>Type name:</dt>
     
    19731972         <dd>none</dd>
    19741973         <dt>Published specification:</dt>
    1975          <dd>This specification (see <a href="#internet.media.type.application.http" title="Internet Media Type application/http">Section&nbsp;9.3.2</a>).
     1974         <dd>This specification (see <a href="#internet.media.type.application.http" title="Internet Media Type application/http">Section&nbsp;8.3.2</a>).
    19761975         </dd>
    19771976         <dt>Applications that use this media type:</dt>
     
    19961995         <dd>IESG</dd>
    19971996      </dl>
    1998       <h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a>&nbsp;<a id="security.considerations" href="#security.considerations">Security Considerations</a></h1>
    1999       <p id="rfc.section.10.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
     1997      <h1 id="rfc.section.9"><a href="#rfc.section.9">9.</a>&nbsp;<a id="security.considerations" href="#security.considerations">Security Considerations</a></h1>
     1998      <p id="rfc.section.9.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
    20001999         as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does
    20012000         make some suggestions for reducing security risks.
    20022001      </p>
    2003       <h2 id="rfc.section.10.1"><a href="#rfc.section.10.1">10.1</a>&nbsp;<a id="personal.information" href="#personal.information">Personal Information</a></h2>
    2004       <p id="rfc.section.10.1.p.1">HTTP clients are often privy to large amounts of personal information (e.g. the user's name, location, mail address, passwords,
     2002      <h2 id="rfc.section.9.1"><a href="#rfc.section.9.1">9.1</a>&nbsp;<a id="personal.information" href="#personal.information">Personal Information</a></h2>
     2003      <p id="rfc.section.9.1.p.1">HTTP clients are often privy to large amounts of personal information (e.g. the user's name, location, mail address, passwords,
    20052004         encryption keys, etc.), and <em class="bcp14">SHOULD</em> be very careful to prevent unintentional leakage of this information. We very strongly recommend that a convenient interface
    20062005         be provided for the user to control dissemination of such information, and that designers and implementors be particularly
     
    20082007         highly adverse publicity for the implementor's company.
    20092008      </p>
    2010       <h2 id="rfc.section.10.2"><a href="#rfc.section.10.2">10.2</a>&nbsp;<a id="abuse.of.server.log.information" href="#abuse.of.server.log.information">Abuse of Server Log Information</a></h2>
    2011       <p id="rfc.section.10.2.p.1">A server is in the position to save personal data about a user's requests which might identify their reading patterns or subjects
     2009      <h2 id="rfc.section.9.2"><a href="#rfc.section.9.2">9.2</a>&nbsp;<a id="abuse.of.server.log.information" href="#abuse.of.server.log.information">Abuse of Server Log Information</a></h2>
     2010      <p id="rfc.section.9.2.p.1">A server is in the position to save personal data about a user's requests which might identify their reading patterns or subjects
    20122011         of interest. This information is clearly confidential in nature and its handling can be constrained by law in certain countries.
    20132012         People using HTTP to provide data are responsible for ensuring that such material is not distributed without the permission
    20142013         of any individuals that are identifiable by the published results.
    20152014      </p>
    2016       <h2 id="rfc.section.10.3"><a href="#rfc.section.10.3">10.3</a>&nbsp;<a id="attack.pathname" href="#attack.pathname">Attacks Based On File and Path Names</a></h2>
    2017       <p id="rfc.section.10.3.p.1">Implementations of HTTP origin servers <em class="bcp14">SHOULD</em> be careful to restrict the documents returned by HTTP requests to be only those that were intended by the server administrators.
     2015      <h2 id="rfc.section.9.3"><a href="#rfc.section.9.3">9.3</a>&nbsp;<a id="attack.pathname" href="#attack.pathname">Attacks Based On File and Path Names</a></h2>
     2016      <p id="rfc.section.9.3.p.1">Implementations of HTTP origin servers <em class="bcp14">SHOULD</em> be careful to restrict the documents returned by HTTP requests to be only those that were intended by the server administrators.
    20182017         If an HTTP server translates HTTP URIs directly into file system calls, the server <em class="bcp14">MUST</em> take special care not to serve files that were not intended to be delivered to HTTP clients. For example, UNIX, Microsoft
    20192018         Windows, and other operating systems use ".." as a path component to indicate a directory level above the current one. On
     
    20232022         bugs in such HTTP server implementations have turned into security risks.
    20242023      </p>
    2025       <h2 id="rfc.section.10.4"><a href="#rfc.section.10.4">10.4</a>&nbsp;<a id="dns.spoofing" href="#dns.spoofing">DNS Spoofing</a></h2>
    2026       <p id="rfc.section.10.4.p.1">Clients using HTTP rely heavily on the Domain Name Service, and are thus generally prone to security attacks based on the
     2024      <h2 id="rfc.section.9.4"><a href="#rfc.section.9.4">9.4</a>&nbsp;<a id="dns.spoofing" href="#dns.spoofing">DNS Spoofing</a></h2>
     2025      <p id="rfc.section.9.4.p.1">Clients using HTTP rely heavily on the Domain Name Service, and are thus generally prone to security attacks based on the
    20272026         deliberate mis-association of IP addresses and DNS names. Clients need to be cautious in assuming the continuing validity
    20282027         of an IP number/DNS name association.
    20292028      </p>
    2030       <p id="rfc.section.10.4.p.2">In particular, HTTP clients <em class="bcp14">SHOULD</em> rely on their name resolver for confirmation of an IP number/DNS name association, rather than caching the result of previous
     2029      <p id="rfc.section.9.4.p.2">In particular, HTTP clients <em class="bcp14">SHOULD</em> rely on their name resolver for confirmation of an IP number/DNS name association, rather than caching the result of previous
    20312030         host name lookups. Many platforms already can cache host name lookups locally when appropriate, and they <em class="bcp14">SHOULD</em> be configured to do so. It is proper for these lookups to be cached, however, only when the TTL (Time To Live) information
    20322031         reported by the name server makes it likely that the cached information will remain useful.
    20332032      </p>
    2034       <p id="rfc.section.10.4.p.3">If HTTP clients cache the results of host name lookups in order to achieve a performance improvement, they <em class="bcp14">MUST</em> observe the TTL information reported by DNS.
    2035       </p>
    2036       <p id="rfc.section.10.4.p.4">If HTTP clients do not observe this rule, they could be spoofed when a previously-accessed server's IP address changes. As
     2033      <p id="rfc.section.9.4.p.3">If HTTP clients cache the results of host name lookups in order to achieve a performance improvement, they <em class="bcp14">MUST</em> observe the TTL information reported by DNS.
     2034      </p>
     2035      <p id="rfc.section.9.4.p.4">If HTTP clients do not observe this rule, they could be spoofed when a previously-accessed server's IP address changes. As
    20372036         network renumbering is expected to become increasingly common <a href="#RFC1900" id="rfc.xref.RFC1900.2"><cite title="Renumbering Needs Work">[RFC1900]</cite></a>, the possibility of this form of attack will grow. Observing this requirement thus reduces this potential security vulnerability.
    20382037      </p>
    2039       <p id="rfc.section.10.4.p.5">This requirement also improves the load-balancing behavior of clients for replicated servers using the same DNS name and reduces
     2038      <p id="rfc.section.9.4.p.5">This requirement also improves the load-balancing behavior of clients for replicated servers using the same DNS name and reduces
    20402039         the likelihood of a user's experiencing failure in accessing sites which use that strategy.
    20412040      </p>
    2042       <h2 id="rfc.section.10.5"><a href="#rfc.section.10.5">10.5</a>&nbsp;<a id="attack.proxies" href="#attack.proxies">Proxies and Caching</a></h2>
    2043       <p id="rfc.section.10.5.p.1">By their very nature, HTTP proxies are men-in-the-middle, and represent an opportunity for man-in-the-middle attacks. Compromise
     2041      <h2 id="rfc.section.9.5"><a href="#rfc.section.9.5">9.5</a>&nbsp;<a id="attack.proxies" href="#attack.proxies">Proxies and Caching</a></h2>
     2042      <p id="rfc.section.9.5.p.1">By their very nature, HTTP proxies are men-in-the-middle, and represent an opportunity for man-in-the-middle attacks. Compromise
    20442043         of the systems on which the proxies run can result in serious security and privacy problems. Proxies have access to security-related
    20452044         information, personal information about individual users and organizations, and proprietary information belonging to users
     
    20472046         might be used in the commission of a wide range of potential attacks.
    20482047      </p>
    2049       <p id="rfc.section.10.5.p.2">Proxy operators should protect the systems on which proxies run as they would protect any system that contains or transports
     2048      <p id="rfc.section.9.5.p.2">Proxy operators should protect the systems on which proxies run as they would protect any system that contains or transports
    20502049         sensitive information. In particular, log information gathered at proxies often contains highly sensitive personal information,
    20512050         and/or information about organizations. Log information should be carefully guarded, and appropriate guidelines for use developed
    2052          and followed. (<a href="#abuse.of.server.log.information" title="Abuse of Server Log Information">Section&nbsp;10.2</a>).
    2053       </p>
    2054       <p id="rfc.section.10.5.p.3">Proxy implementors should consider the privacy and security implications of their design and coding decisions, and of the
     2051         and followed. (<a href="#abuse.of.server.log.information" title="Abuse of Server Log Information">Section&nbsp;9.2</a>).
     2052      </p>
     2053      <p id="rfc.section.9.5.p.3">Proxy implementors should consider the privacy and security implications of their design and coding decisions, and of the
    20552054         configuration options they provide to proxy operators (especially the default configuration).
    20562055      </p>
    2057       <p id="rfc.section.10.5.p.4">Users of a proxy need to be aware that they are no trustworthier than the people who run the proxy; HTTP itself cannot solve
     2056      <p id="rfc.section.9.5.p.4">Users of a proxy need to be aware that they are no trustworthier than the people who run the proxy; HTTP itself cannot solve
    20582057         this problem.
    20592058      </p>
    2060       <p id="rfc.section.10.5.p.5">The judicious use of cryptography, when appropriate, may suffice to protect against a broad range of security and privacy
     2059      <p id="rfc.section.9.5.p.5">The judicious use of cryptography, when appropriate, may suffice to protect against a broad range of security and privacy
    20612060         attacks. Such cryptography is beyond the scope of the HTTP/1.1 specification.
    20622061      </p>
    2063       <h2 id="rfc.section.10.6"><a href="#rfc.section.10.6">10.6</a>&nbsp;<a id="attack.DoS" href="#attack.DoS">Denial of Service Attacks on Proxies</a></h2>
    2064       <p id="rfc.section.10.6.p.1">They exist. They are hard to defend against. Research continues. Beware.</p>
    2065       <h1 id="rfc.section.11"><a href="#rfc.section.11">11.</a>&nbsp;<a id="ack" href="#ack">Acknowledgments</a></h1>
    2066       <p id="rfc.section.11.p.1">HTTP has evolved considerably over the years. It has benefited from a large and active developer community--the many people
     2062      <h2 id="rfc.section.9.6"><a href="#rfc.section.9.6">9.6</a>&nbsp;<a id="attack.DoS" href="#attack.DoS">Denial of Service Attacks on Proxies</a></h2>
     2063      <p id="rfc.section.9.6.p.1">They exist. They are hard to defend against. Research continues. Beware.</p>
     2064      <h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a>&nbsp;<a id="ack" href="#ack">Acknowledgments</a></h1>
     2065      <p id="rfc.section.10.p.1">HTTP has evolved considerably over the years. It has benefited from a large and active developer community--the many people
    20672066         who have participated on the www-talk mailing list--and it is that community which has been most responsible for the success
    20682067         of HTTP and of the World-Wide Web in general. Marc Andreessen, Robert Cailliau, Daniel W. Connolly, Bob Denny, John Franks,
     
    20702069         and Marc VanHeyningen deserve special recognition for their efforts in defining early aspects of the protocol.
    20712070      </p>
    2072       <p id="rfc.section.11.p.2">This document has benefited greatly from the comments of all those participating in the HTTP-WG. In addition to those already
     2071      <p id="rfc.section.10.p.2">This document has benefited greatly from the comments of all those participating in the HTTP-WG. In addition to those already
    20732072         mentioned, the following individuals have contributed to this specification:
    20742073      </p>
    2075       <p id="rfc.section.11.p.3">Gary Adams, Harald Tveit Alvestrand, Keith Ball, Brian Behlendorf, Paul Burchard, Maurizio Codogno, Mike Cowlishaw, Roman
     2074      <p id="rfc.section.10.p.3">Gary Adams, Harald Tveit Alvestrand, Keith Ball, Brian Behlendorf, Paul Burchard, Maurizio Codogno, Mike Cowlishaw, Roman
    20762075         Czyborra, Michael A. Dolan, Daniel DuBois, David J. Fiander, Alan Freier, Marc Hedlund, Greg Herlihy, Koen Holtman, Alex Hopmann,
    20772076         Bob Jernigan, Shel Kaphan, Rohit Khare, John Klensin, Martijn Koster, Alexei Kosut, David M. Kristol, Daniel LaLiberte, Ben
     
    20812080         Weinman, Francois Yergeau, Mary Ellen Zurko, Josh Cohen.
    20822081      </p>
    2083       <p id="rfc.section.11.p.4">Thanks to the "cave men" of Palo Alto. You know who you are.</p>
    2084       <p id="rfc.section.11.p.5">Jim Gettys (the editor of <a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>) wishes particularly to thank Roy Fielding, the editor of <a href="#RFC2068" id="rfc.xref.RFC2068.5"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, along with John Klensin, Jeff Mogul, Paul Leach, Dave Kristol, Koen Holtman, John Franks, Josh Cohen, Alex Hopmann, Scott
     2082      <p id="rfc.section.10.p.4">Thanks to the "cave men" of Palo Alto. You know who you are.</p>
     2083      <p id="rfc.section.10.p.5">Jim Gettys (the editor of <a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>) wishes particularly to thank Roy Fielding, the editor of <a href="#RFC2068" id="rfc.xref.RFC2068.5"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, along with John Klensin, Jeff Mogul, Paul Leach, Dave Kristol, Koen Holtman, John Franks, Josh Cohen, Alex Hopmann, Scott
    20852084         Lawrence, and Larry Masinter for their help. And thanks go particularly to Jeff Mogul and Scott Lawrence for performing the
    20862085         "MUST/MAY/SHOULD" audit.
    20872086      </p>
    2088       <p id="rfc.section.11.p.6">The Apache Group, Anselm Baird-Smith, author of Jigsaw, and Henrik Frystyk implemented RFC 2068 early, and we wish to thank
     2087      <p id="rfc.section.10.p.6">The Apache Group, Anselm Baird-Smith, author of Jigsaw, and Henrik Frystyk implemented RFC 2068 early, and we wish to thank
    20892088         them for the discovery of many of the problems that this document attempts to rectify.
    20902089      </p>
    2091       <p id="rfc.section.11.p.7">This specification makes heavy use of the augmented BNF and generic constructs defined by David H. Crocker for <a href="#RFC5234" id="rfc.xref.RFC5234.4"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. Similarly, it reuses many of the definitions provided by Nathaniel Borenstein and Ned Freed for MIME <a href="#RFC2045" id="rfc.xref.RFC2045.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>. We hope that their inclusion in this specification will help reduce past confusion over the relationship between HTTP and
     2090      <p id="rfc.section.10.p.7">This specification makes heavy use of the augmented BNF and generic constructs defined by David H. Crocker for <a href="#RFC5234" id="rfc.xref.RFC5234.4"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. Similarly, it reuses many of the definitions provided by Nathaniel Borenstein and Ned Freed for MIME <a href="#RFC2045" id="rfc.xref.RFC2045.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>. We hope that their inclusion in this specification will help reduce past confusion over the relationship between HTTP and
    20922091         Internet mail message formats.
    20932092      </p>
    2094       <h1 id="rfc.references"><a id="rfc.section.12" href="#rfc.section.12">12.</a> References
     2093      <h1 id="rfc.references"><a id="rfc.section.11" href="#rfc.section.11">11.</a> References
    20952094      </h1>
    2096       <h2 id="rfc.references.1"><a href="#rfc.section.12.1" id="rfc.section.12.1">12.1</a> Normative References
     2095      <h2 id="rfc.references.1"><a href="#rfc.section.11.1" id="rfc.section.11.1">11.1</a> Normative References
    20972096      </h2>
    20982097      <table summary="Normative References">                     
     
    21542153         </tr>
    21552154      </table>
    2156       <h2 id="rfc.references.2"><a href="#rfc.section.12.2" id="rfc.section.12.2">12.2</a> Informative References
     2155      <h2 id="rfc.references.2"><a href="#rfc.section.11.2" id="rfc.section.11.2">11.2</a> Informative References
    21572156      </h2>
    21582157      <table summary="Informative References">                                             
     
    23492348      <p id="rfc.section.B.1.p.1">This section summarizes major differences between versions HTTP/1.0 and HTTP/1.1.</p>
    23502349      <h3 id="rfc.section.B.1.1"><a href="#rfc.section.B.1.1">B.1.1</a>&nbsp;<a id="changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses">Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses</a></h3>
    2351       <p id="rfc.section.B.1.1.p.1">The requirements that clients and servers support the Host request-header, report an error if the Host request-header (<a href="#header.host" id="rfc.xref.header.host.2" title="Host">Section&nbsp;8.4</a>) is missing from an HTTP/1.1 request, and accept absolute URIs (<a href="#request-uri" title="Request-URI">Section&nbsp;5.1.2</a>) are among the most important changes defined by this specification.
     2350      <p id="rfc.section.B.1.1.p.1">The requirements that clients and servers support the Host request-header, report an error if the Host request-header (<a href="#header.host" id="rfc.xref.header.host.2" title="Host">Section&nbsp;7.4</a>) is missing from an HTTP/1.1 request, and accept absolute URIs (<a href="#request-uri" title="Request-URI">Section&nbsp;4.1.2</a>) are among the most important changes defined by this specification.
    23522351      </p>
    23532352      <p id="rfc.section.B.1.1.p.2">Older HTTP/1.0 clients assumed a one-to-one relationship of IP addresses and servers; there was no other established mechanism
     
    23822381         Therefore, we need some other mechanism for indicating a persistent connection is desired, which is safe to use even when
    23832382         talking to an old proxy that ignores Connection. Persistent connections are the default for HTTP/1.1 messages; we introduce
    2384          a new keyword (Connection: close) for declaring non-persistence. See <a href="#header.connection" id="rfc.xref.header.connection.7" title="Connection">Section&nbsp;8.1</a>.
     2383         a new keyword (Connection: close) for declaring non-persistence. See <a href="#header.connection" id="rfc.xref.header.connection.7" title="Connection">Section&nbsp;7.1</a>.
    23852384      </p>
    23862385      <p id="rfc.section.B.2.p.3">The original HTTP/1.0 form of persistent connections (the Connection: Keep-Alive and Keep-Alive header) is documented in <a href="#RFC2068" id="rfc.xref.RFC2068.7"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>.
     
    23922391      <p id="rfc.section.B.3.p.2">Transfer-coding and message lengths all interact in ways that required fixing exactly when chunked encoding is used (to allow
    23932392         for transfer encoding that may not be self delimiting); it was important to straighten out exactly how message lengths are
    2394          computed. (Sections <a href="#transfer.codings" title="Transfer Codings">3.4</a>, <a href="#message.length" title="Message Length">4.4</a>, <a href="#header.content-length" id="rfc.xref.header.content-length.3" title="Content-Length">8.2</a>, see also <a href="#Part3" id="rfc.xref.Part3.14"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="#Part5" id="rfc.xref.Part5.1"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a> and <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>)
     2393         computed. (Sections <a href="#transfer.codings" title="Transfer Codings">2.4</a>, <a href="#message.length" title="Message Length">3.4</a>, <a href="#header.content-length" id="rfc.xref.header.content-length.3" title="Content-Length">7.2</a>, see also <a href="#Part3" id="rfc.xref.Part3.14"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="#Part5" id="rfc.xref.Part5.1"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a> and <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>)
    23952394      </p>
    23962395      <p id="rfc.section.B.3.p.3">The use and interpretation of HTTP version numbers has been clarified by <a href="#RFC2145" id="rfc.xref.RFC2145.3"><cite title="Use and Interpretation of HTTP Version Numbers">[RFC2145]</cite></a>. Require proxies to upgrade requests to highest protocol version they support to deal with problems discovered in HTTP/1.0
    2397          implementations (<a href="#http.version" title="HTTP Version">Section&nbsp;3.1</a>)
     2396         implementations (<a href="#http.version" title="HTTP Version">Section&nbsp;2.1</a>)
    23982397      </p>
    23992398      <p id="rfc.section.B.3.p.4">Transfer-coding had significant problems, particularly with interactions with chunked encoding. The solution is that transfer-codings
     
    24012400         codings), a new header field (TE) and enabling trailer headers in the future. Transfer encoding is a major performance benefit,
    24022401         so it was worth fixing <a href="#Nie1997" id="rfc.xref.Nie1997.2"><cite title="Network Performance Effects of HTTP/1.1, CSS1, and PNG">[Nie1997]</cite></a>. TE also solves another, obscure, downward interoperability problem that could have occurred due to interactions between
    2403          authentication trailers, chunked encoding and HTTP/1.0 clients.(Section <a href="#transfer.codings" title="Transfer Codings">3.4</a>, <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">3.4.1</a>, and <a href="#header.te" id="rfc.xref.header.te.4" title="TE">8.5</a>)
     2402         authentication trailers, chunked encoding and HTTP/1.0 clients.(Section <a href="#transfer.codings" title="Transfer Codings">2.4</a>, <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">2.4.1</a>, and <a href="#header.te" id="rfc.xref.header.te.4" title="TE">7.5</a>)
    24042403      </p>
    24052404      <h2 id="rfc.section.B.4"><a href="#rfc.section.B.4">B.4</a>&nbsp;<a id="changes.from.rfc.2616" href="#changes.from.rfc.2616">Changes from RFC 2616</a></h2>
    24062405      <p id="rfc.section.B.4.p.1">Rules about implicit linear white space between certain grammar productions have been removed; now it's only allowed when
    24072406         specifically pointed out in the ABNF. The CHAR rule does not allow the NUL character anymore (this affects the comment and
    2408          quoted-string rules). Furthermore, the quoted-pair rule does not allow escaping NUL, CR or LF anymore. (<a href="#basic.rules" title="Basic Rules">Section&nbsp;2.2</a>)
    2409       </p>
    2410       <p id="rfc.section.B.4.p.2">Clarify that HTTP-Version is case sensitive. (<a href="#http.version" title="HTTP Version">Section&nbsp;3.1</a>)
    2411       </p>
    2412       <p id="rfc.section.B.4.p.3">Remove reference to non-existant identity transfer-coding value tokens. (Sections <a href="#transfer.codings" title="Transfer Codings">3.4</a> and <a href="#message.length" title="Message Length">4.4</a>)
    2413       </p>
    2414       <p id="rfc.section.B.4.p.4">Clarification that the chunk length does not include the count of the octets in the chunk header and trailer. (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;3.4.1</a>)
    2415       </p>
    2416       <p id="rfc.section.B.4.p.5">Update use of abs_path production from RFC1808 to the path-absolute + query components of RFC3986. (<a href="#request-uri" title="Request-URI">Section&nbsp;5.1.2</a>)
    2417       </p>
    2418       <p id="rfc.section.B.4.p.6">Clarify exactly when close connection options must be sent. (<a href="#header.connection" id="rfc.xref.header.connection.8" title="Connection">Section&nbsp;8.1</a>)
     2407         quoted-string rules). Furthermore, the quoted-pair rule does not allow escaping NUL, CR or LF anymore. (<a href="#basic.rules" title="Basic Rules">Section&nbsp;1.2.2</a>)
     2408      </p>
     2409      <p id="rfc.section.B.4.p.2">Clarify that HTTP-Version is case sensitive. (<a href="#http.version" title="HTTP Version">Section&nbsp;2.1</a>)
     2410      </p>
     2411      <p id="rfc.section.B.4.p.3">Remove reference to non-existant identity transfer-coding value tokens. (Sections <a href="#transfer.codings" title="Transfer Codings">2.4</a> and <a href="#message.length" title="Message Length">3.4</a>)
     2412      </p>
     2413      <p id="rfc.section.B.4.p.4">Clarification that the chunk length does not include the count of the octets in the chunk header and trailer. (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section&nbsp;2.4.1</a>)
     2414      </p>
     2415      <p id="rfc.section.B.4.p.5">Update use of abs_path production from RFC1808 to the path-absolute + query components of RFC3986. (<a href="#request-uri" title="Request-URI">Section&nbsp;4.1.2</a>)
     2416      </p>
     2417      <p id="rfc.section.B.4.p.6">Clarify exactly when close connection options must be sent. (<a href="#header.connection" id="rfc.xref.header.connection.8" title="Connection">Section&nbsp;7.1</a>)
    24192418      </p>
    24202419      <h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a>&nbsp;<a id="terminology" href="#terminology">Terminology</a></h1>
     
    24282427      </p>
    24292428      <dl class="empty">
    2430          <dd>The basic unit of HTTP communication, consisting of a structured sequence of octets matching the syntax defined in <a href="#http.message" title="HTTP Message">Section&nbsp;4</a> and transmitted via the connection.
     2429         <dd>The basic unit of HTTP communication, consisting of a structured sequence of octets matching the syntax defined in <a href="#http.message" title="HTTP Message">Section&nbsp;3</a> and transmitted via the connection.
    24312430         </dd>
    24322431      </dl>
     
    24342433      </p>
    24352434      <dl class="empty">
    2436          <dd>An HTTP request message, as defined in <a href="#request" title="Request">Section&nbsp;5</a>.
     2435         <dd>An HTTP request message, as defined in <a href="#request" title="Request">Section&nbsp;4</a>.
    24372436         </dd>
    24382437      </dl>
     
    24402439      </p>
    24412440      <dl class="empty">
    2442          <dd>An HTTP response message, as defined in <a href="#response" title="Response">Section&nbsp;6</a>.
     2441         <dd>An HTTP response message, as defined in <a href="#response" title="Response">Section&nbsp;5</a>.
    24432442         </dd>
    24442443      </dl>
     
    24462445      </p>
    24472446      <dl class="empty">
    2448          <dd>A network data object or service that can be identified by a URI, as defined in <a href="#uri" title="Uniform Resource Identifiers">Section&nbsp;3.2</a>. Resources may be available in multiple representations (e.g. multiple languages, data formats, size, and resolutions) or
     2447         <dd>A network data object or service that can be identified by a URI, as defined in <a href="#uri" title="Uniform Resource Identifiers">Section&nbsp;2.2</a>. Resources may be available in multiple representations (e.g. multiple languages, data formats, size, and resolutions) or
    24492448            vary in other ways.
    24502449         </dd>
     
    27332732         <ul class="ind">
    27342733            <li class="indline0"><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul class="ind">
    2735                   <li class="indline1">application/http Media Type&nbsp;&nbsp;<a class="iref" href="#rfc.iref.a.1"><b>9.3.2</b></a></li>
     2734                  <li class="indline1">application/http Media Type&nbsp;&nbsp;<a class="iref" href="#rfc.iref.a.1"><b>8.3.2</b></a></li>
    27362735               </ul>
    27372736            </li>
     
    27412740                  <li class="indline1">client&nbsp;&nbsp;<a class="iref" href="#rfc.iref.c.5">C</a></li>
    27422741                  <li class="indline1">connection&nbsp;&nbsp;<a class="iref" href="#rfc.iref.c.3">C</a></li>
    2743                   <li class="indline1">Connection header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.connection.1">4.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">7.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">7.1.3</a>, <a class="iref" href="#rfc.iref.c.1"><b>8.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">8.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">8.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">9.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li>
     2742                  <li class="indline1">Connection header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.connection.1">3.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">6.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">6.1.3</a>, <a class="iref" href="#rfc.iref.c.1"><b>7.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">7.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">7.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">8.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li>
    27442743                  <li class="indline1">content negotiation&nbsp;&nbsp;<a class="iref" href="#rfc.iref.c.4">C</a></li>
    2745                   <li class="indline1">Content-Length header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.content-length.1">4.4</a>, <a class="iref" href="#rfc.iref.c.2"><b>8.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">9.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li>
     2744                  <li class="indline1">Content-Length header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.content-length.1">3.4</a>, <a class="iref" href="#rfc.iref.c.2"><b>7.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">8.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li>
    27462745               </ul>
    27472746            </li>
    27482747            <li class="indline0"><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul class="ind">
    2749                   <li class="indline1">Date header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.date.1">4.5</a>, <a class="iref" href="#rfc.iref.d.1"><b>8.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">9.1</a></li>
     2748                  <li class="indline1">Date header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.date.1">3.5</a>, <a class="iref" href="#rfc.iref.d.1"><b>7.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">8.1</a></li>
    27502749                  <li class="indline1">downstream&nbsp;&nbsp;<a class="iref" href="#rfc.iref.d.2">C</a></li>
    27512750               </ul>
     
    27592758                  <li class="indline1"><tt>Grammar</tt>&nbsp;&nbsp;
    27602759                     <ul class="ind">
    2761                         <li class="indline1"><tt>absolute-URI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.16"><b>3.2</b></a></li>
    2762                         <li class="indline1"><tt>asctime-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.29"><b>3.3.1</b></a></li>
    2763                         <li class="indline1"><tt>attribute</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.40"><b>3.4</b></a></li>
    2764                         <li class="indline1"><tt>authority</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.17"><b>3.2</b></a></li>
    2765                         <li class="indline1"><tt>BWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.3"><b>2.2</b></a></li>
    2766                         <li class="indline1"><tt>chunk</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.43"><b>3.4.1</b></a></li>
    2767                         <li class="indline1"><tt>chunk-data</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.49"><b>3.4.1</b></a></li>
    2768                         <li class="indline1"><tt>chunk-ext</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.46"><b>3.4.1</b></a></li>
    2769                         <li class="indline1"><tt>chunk-ext-name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.47"><b>3.4.1</b></a></li>
    2770                         <li class="indline1"><tt>chunk-ext-val</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.48"><b>3.4.1</b></a></li>
    2771                         <li class="indline1"><tt>chunk-size</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.44"><b>3.4.1</b></a></li>
    2772                         <li class="indline1"><tt>Chunked-Body</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.42"><b>3.4.1</b></a></li>
    2773                         <li class="indline1"><tt>comment</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.7"><b>2.2</b></a></li>
    2774                         <li class="indline1"><tt>Connection</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.72"><b>8.1</b></a></li>
    2775                         <li class="indline1"><tt>connection-token</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.74"><b>8.1</b></a></li>
    2776                         <li class="indline1"><tt>Connection-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.73"><b>8.1</b></a></li>
    2777                         <li class="indline1"><tt>Content-Length</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.75"><b>8.2</b></a></li>
    2778                         <li class="indline1"><tt>Content-Length-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.76"><b>8.2</b></a></li>
    2779                         <li class="indline1"><tt>ctext</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.8"><b>2.2</b></a></li>
    2780                         <li class="indline1"><tt>Date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.77"><b>8.3</b></a></li>
    2781                         <li class="indline1"><tt>Date-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.78"><b>8.3</b></a></li>
    2782                         <li class="indline1"><tt>date1</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.30"><b>3.3.1</b></a></li>
    2783                         <li class="indline1"><tt>date2</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.31"><b>3.3.1</b></a></li>
    2784                         <li class="indline1"><tt>date3</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.32"><b>3.3.1</b></a></li>
    2785                         <li class="indline1"><tt>extension-code</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.70"><b>6.1.1</b></a></li>
    2786                         <li class="indline1"><tt>extension-method</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.65"><b>5.1.1</b></a></li>
    2787                         <li class="indline1"><tt>field-content</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.59"><b>4.2</b></a></li>
    2788                         <li class="indline1"><tt>field-name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.57"><b>4.2</b></a></li>
    2789                         <li class="indline1"><tt>field-value</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.58"><b>4.2</b></a></li>
    2790                         <li class="indline1"><tt>general-header</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.61"><b>4.5</b></a></li>
    2791                         <li class="indline1"><tt>generic-message</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.54"><b>4.1</b></a></li>
    2792                         <li class="indline1"><tt>Host</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.79"><b>8.4</b></a></li>
    2793                         <li class="indline1"><tt>Host-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.80"><b>8.4</b></a></li>
    2794                         <li class="indline1"><tt>HTTP-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.25"><b>3.3.1</b></a></li>
    2795                         <li class="indline1"><tt>HTTP-message</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.53"><b>4.1</b></a></li>
    2796                         <li class="indline1"><tt>HTTP-Prot-Name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.14"><b>3.1</b></a></li>
    2797                         <li class="indline1"><tt>http-URI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.24"><b>3.2.1</b></a></li>
    2798                         <li class="indline1"><tt>HTTP-Version</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.13"><b>3.1</b></a></li>
    2799                         <li class="indline1"><tt>last-chunk</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.45"><b>3.4.1</b></a></li>
    2800                         <li class="indline1"><tt>message-body</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.60"><b>4.3</b></a></li>
    2801                         <li class="indline1"><tt>message-header</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.56"><b>4.2</b></a></li>
    2802                         <li class="indline1"><tt>Method</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.64"><b>5.1.1</b></a></li>
    2803                         <li class="indline1"><tt>month</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.36"><b>3.3.1</b></a></li>
    2804                         <li class="indline1"><tt>obsolete-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.27"><b>3.3.1</b></a></li>
    2805                         <li class="indline1"><tt>OWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.1"><b>2.2</b></a></li>
    2806                         <li class="indline1"><tt>parameter</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.39"><b>3.4</b></a></li>
    2807                         <li class="indline1"><tt>path-absolute</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.18"><b>3.2</b></a></li>
    2808                         <li class="indline1"><tt>port</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.19"><b>3.2</b></a></li>
    2809                         <li class="indline1"><tt>product</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.51"><b>3.5</b></a></li>
    2810                         <li class="indline1"><tt>product-version</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.52"><b>3.5</b></a></li>
    2811                         <li class="indline1"><tt>protocol-name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.93"><b>8.9</b></a></li>
    2812                         <li class="indline1"><tt>protocol-version</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.94"><b>8.9</b></a></li>
    2813                         <li class="indline1"><tt>pseudonym</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.96"><b>8.9</b></a></li>
    2814                         <li class="indline1"><tt>qdtext</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.10"><b>2.2</b></a></li>
    2815                         <li class="indline1"><tt>query</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.20"><b>3.2</b></a></li>
    2816                         <li class="indline1"><tt>quoted-pair</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.12"><b>2.2</b></a></li>
    2817                         <li class="indline1"><tt>quoted-string</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.9"><b>2.2</b></a></li>
    2818                         <li class="indline1"><tt>quoted-text</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.11"><b>2.2</b></a></li>
    2819                         <li class="indline1"><tt>Reason-Phrase</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.71"><b>6.1.1</b></a></li>
    2820                         <li class="indline1"><tt>received-by</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.95"><b>8.9</b></a></li>
    2821                         <li class="indline1"><tt>received-protocol</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.92"><b>8.9</b></a></li>
    2822                         <li class="indline1"><tt>relative-part</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.23"><b>3.2</b></a></li>
    2823                         <li class="indline1"><tt>relativeURI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.22"><b>3.2</b></a></li>
    2824                         <li class="indline1"><tt>Request</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.62"><b>5</b></a></li>
    2825                         <li class="indline1"><tt>Request-Line</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.63"><b>5.1</b></a></li>
    2826                         <li class="indline1"><tt>Request-URI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.66"><b>5.1.2</b></a></li>
    2827                         <li class="indline1"><tt>Response</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.67"><b>6</b></a></li>
    2828                         <li class="indline1"><tt>rfc1123-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.26"><b>3.3.1</b></a></li>
    2829                         <li class="indline1"><tt>rfc850-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.28"><b>3.3.1</b></a></li>
    2830                         <li class="indline1"><tt>RWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.2"><b>2.2</b></a></li>
    2831                         <li class="indline1"><tt>start-line</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.55"><b>4.1</b></a></li>
    2832                         <li class="indline1"><tt>Status-Code</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.69"><b>6.1.1</b></a></li>
    2833                         <li class="indline1"><tt>Status-Line</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.68"><b>6.1</b></a></li>
    2834                         <li class="indline1"><tt>t-codings</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.83"><b>8.5</b></a></li>
    2835                         <li class="indline1"><tt>tchar</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.6"><b>2.2</b></a></li>
    2836                         <li class="indline1"><tt>TE</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.81"><b>8.5</b></a></li>
    2837                         <li class="indline1"><tt>TE-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.82"><b>8.5</b></a></li>
    2838                         <li class="indline1"><tt>TEXT</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.4"><b>2.2</b></a></li>
    2839                         <li class="indline1"><tt>time</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.33"><b>3.3.1</b></a></li>
    2840                         <li class="indline1"><tt>token</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.5"><b>2.2</b></a></li>
    2841                         <li class="indline1"><tt>Trailer</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.84"><b>8.6</b></a></li>
    2842                         <li class="indline1"><tt>trailer-part</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.50"><b>3.4.1</b></a></li>
    2843                         <li class="indline1"><tt>Trailer-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.85"><b>8.6</b></a></li>
    2844                         <li class="indline1"><tt>transfer-coding</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.37"><b>3.4</b></a></li>
    2845                         <li class="indline1"><tt>Transfer-Encoding</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.86"><b>8.7</b></a></li>
    2846                         <li class="indline1"><tt>Transfer-Encoding-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.87"><b>8.7</b></a></li>
    2847                         <li class="indline1"><tt>transfer-extension</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.38"><b>3.4</b></a></li>
    2848                         <li class="indline1"><tt>Upgrade</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.88"><b>8.8</b></a></li>
    2849                         <li class="indline1"><tt>Upgrade-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.89"><b>8.8</b></a></li>
    2850                         <li class="indline1"><tt>uri-host</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.21"><b>3.2</b></a></li>
    2851                         <li class="indline1"><tt>URI-reference</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.15"><b>3.2</b></a></li>
    2852                         <li class="indline1"><tt>value</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.41"><b>3.4</b></a></li>
    2853                         <li class="indline1"><tt>Via</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.90"><b>8.9</b></a></li>
    2854                         <li class="indline1"><tt>Via-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.91"><b>8.9</b></a></li>
    2855                         <li class="indline1"><tt>weekday</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.35"><b>3.3.1</b></a></li>
    2856                         <li class="indline1"><tt>wkday</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.34"><b>3.3.1</b></a></li>
     2760                        <li class="indline1"><tt>absolute-URI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.16"><b>2.2</b></a></li>
     2761                        <li class="indline1"><tt>asctime-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.29"><b>2.3.1</b></a></li>
     2762                        <li class="indline1"><tt>attribute</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.40"><b>2.4</b></a></li>
     2763                        <li class="indline1"><tt>authority</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.17"><b>2.2</b></a></li>
     2764                        <li class="indline1"><tt>BWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.3"><b>1.2.2</b></a></li>
     2765                        <li class="indline1"><tt>chunk</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.43"><b>2.4.1</b></a></li>
     2766                        <li class="indline1"><tt>chunk-data</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.49"><b>2.4.1</b></a></li>
     2767                        <li class="indline1"><tt>chunk-ext</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.46"><b>2.4.1</b></a></li>
     2768                        <li class="indline1"><tt>chunk-ext-name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.47"><b>2.4.1</b></a></li>
     2769                        <li class="indline1"><tt>chunk-ext-val</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.48"><b>2.4.1</b></a></li>
     2770                        <li class="indline1"><tt>chunk-size</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.44"><b>2.4.1</b></a></li>
     2771                        <li class="indline1"><tt>Chunked-Body</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.42"><b>2.4.1</b></a></li>
     2772                        <li class="indline1"><tt>comment</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.7"><b>1.2.2</b></a></li>
     2773                        <li class="indline1"><tt>Connection</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.72"><b>7.1</b></a></li>
     2774                        <li class="indline1"><tt>connection-token</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.74"><b>7.1</b></a></li>
     2775                        <li class="indline1"><tt>Connection-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.73"><b>7.1</b></a></li>
     2776                        <li class="indline1"><tt>Content-Length</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.75"><b>7.2</b></a></li>
     2777                        <li class="indline1"><tt>Content-Length-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.76"><b>7.2</b></a></li>
     2778                        <li class="indline1"><tt>ctext</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.8"><b>1.2.2</b></a></li>
     2779                        <li class="indline1"><tt>Date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.77"><b>7.3</b></a></li>
     2780                        <li class="indline1"><tt>Date-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.78"><b>7.3</b></a></li>
     2781                        <li class="indline1"><tt>date1</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.30"><b>2.3.1</b></a></li>
     2782                        <li class="indline1"><tt>date2</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.31"><b>2.3.1</b></a></li>
     2783                        <li class="indline1"><tt>date3</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.32"><b>2.3.1</b></a></li>
     2784                        <li class="indline1"><tt>extension-code</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.70"><b>5.1.1</b></a></li>
     2785                        <li class="indline1"><tt>extension-method</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.65"><b>4.1.1</b></a></li>
     2786                        <li class="indline1"><tt>field-content</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.59"><b>3.2</b></a></li>
     2787                        <li class="indline1"><tt>field-name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.57"><b>3.2</b></a></li>
     2788                        <li class="indline1"><tt>field-value</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.58"><b>3.2</b></a></li>
     2789                        <li class="indline1"><tt>general-header</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.61"><b>3.5</b></a></li>
     2790                        <li class="indline1"><tt>generic-message</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.54"><b>3.1</b></a></li>
     2791                        <li class="indline1"><tt>Host</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.79"><b>7.4</b></a></li>
     2792                        <li class="indline1"><tt>Host-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.80"><b>7.4</b></a></li>
     2793                        <li class="indline1"><tt>HTTP-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.25"><b>2.3.1</b></a></li>
     2794                        <li class="indline1"><tt>HTTP-message</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.53"><b>3.1</b></a></li>
     2795                        <li class="indline1"><tt>HTTP-Prot-Name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.14"><b>2.1</b></a></li>
     2796                        <li class="indline1"><tt>http-URI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.24"><b>2.2.1</b></a></li>
     2797                        <li class="indline1"><tt>HTTP-Version</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.13"><b>2.1</b></a></li>
     2798                        <li class="indline1"><tt>last-chunk</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.45"><b>2.4.1</b></a></li>
     2799                        <li class="indline1"><tt>message-body</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.60"><b>3.3</b></a></li>
     2800                        <li class="indline1"><tt>message-header</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.56"><b>3.2</b></a></li>
     2801                        <li class="indline1"><tt>Method</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.64"><b>4.1.1</b></a></li>
     2802                        <li class="indline1"><tt>month</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.36"><b>2.3.1</b></a></li>
     2803                        <li class="indline1"><tt>obsolete-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.27"><b>2.3.1</b></a></li>
     2804                        <li class="indline1"><tt>OWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.1"><b>1.2.2</b></a></li>
     2805                        <li class="indline1"><tt>parameter</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.39"><b>2.4</b></a></li>
     2806                        <li class="indline1"><tt>path-absolute</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.18"><b>2.2</b></a></li>
     2807                        <li class="indline1"><tt>port</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.19"><b>2.2</b></a></li>
     2808                        <li class="indline1"><tt>product</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.51"><b>2.5</b></a></li>
     2809                        <li class="indline1"><tt>product-version</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.52"><b>2.5</b></a></li>
     2810                        <li class="indline1"><tt>protocol-name</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.93"><b>7.9</b></a></li>
     2811                        <li class="indline1"><tt>protocol-version</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.94"><b>7.9</b></a></li>
     2812                        <li class="indline1"><tt>pseudonym</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.96"><b>7.9</b></a></li>
     2813                        <li class="indline1"><tt>qdtext</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.10"><b>1.2.2</b></a></li>
     2814                        <li class="indline1"><tt>query</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.20"><b>2.2</b></a></li>
     2815                        <li class="indline1"><tt>quoted-pair</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.12"><b>1.2.2</b></a></li>
     2816                        <li class="indline1"><tt>quoted-string</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.9"><b>1.2.2</b></a></li>
     2817                        <li class="indline1"><tt>quoted-text</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.11"><b>1.2.2</b></a></li>
     2818                        <li class="indline1"><tt>Reason-Phrase</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.71"><b>5.1.1</b></a></li>
     2819                        <li class="indline1"><tt>received-by</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.95"><b>7.9</b></a></li>
     2820                        <li class="indline1"><tt>received-protocol</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.92"><b>7.9</b></a></li>
     2821                        <li class="indline1"><tt>relative-part</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.23"><b>2.2</b></a></li>
     2822                        <li class="indline1"><tt>relativeURI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.22"><b>2.2</b></a></li>
     2823                        <li class="indline1"><tt>Request</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.62"><b>4</b></a></li>
     2824                        <li class="indline1"><tt>Request-Line</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.63"><b>4.1</b></a></li>
     2825                        <li class="indline1"><tt>Request-URI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.66"><b>4.1.2</b></a></li>
     2826                        <li class="indline1"><tt>Response</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.67"><b>5</b></a></li>
     2827                        <li class="indline1"><tt>rfc1123-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.26"><b>2.3.1</b></a></li>
     2828                        <li class="indline1"><tt>rfc850-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.28"><b>2.3.1</b></a></li>
     2829                        <li class="indline1"><tt>RWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.2"><b>1.2.2</b></a></li>
     2830                        <li class="indline1"><tt>start-line</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.55"><b>3.1</b></a></li>
     2831                        <li class="indline1"><tt>Status-Code</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.69"><b>5.1.1</b></a></li>
     2832                        <li class="indline1"><tt>Status-Line</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.68"><b>5.1</b></a></li>
     2833                        <li class="indline1"><tt>t-codings</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.83"><b>7.5</b></a></li>
     2834                        <li class="indline1"><tt>tchar</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.6"><b>1.2.2</b></a></li>
     2835                        <li class="indline1"><tt>TE</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.81"><b>7.5</b></a></li>
     2836                        <li class="indline1"><tt>TE-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.82"><b>7.5</b></a></li>
     2837                        <li class="indline1"><tt>TEXT</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.4"><b>1.2.2</b></a></li>
     2838                        <li class="indline1"><tt>time</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.33"><b>2.3.1</b></a></li>
     2839                        <li class="indline1"><tt>token</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.5"><b>1.2.2</b></a></li>
     2840                        <li class="indline1"><tt>Trailer</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.84"><b>7.6</b></a></li>
     2841                        <li class="indline1"><tt>trailer-part</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.50"><b>2.4.1</b></a></li>
     2842                        <li class="indline1"><tt>Trailer-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.85"><b>7.6</b></a></li>
     2843                        <li class="indline1"><tt>transfer-coding</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.37"><b>2.4</b></a></li>
     2844                        <li class="indline1"><tt>Transfer-Encoding</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.86"><b>7.7</b></a></li>
     2845                        <li class="indline1"><tt>Transfer-Encoding-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.87"><b>7.7</b></a></li>
     2846                        <li class="indline1"><tt>transfer-extension</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.38"><b>2.4</b></a></li>
     2847                        <li class="indline1"><tt>Upgrade</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.88"><b>7.8</b></a></li>
     2848                        <li class="indline1"><tt>Upgrade-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.89"><b>7.8</b></a></li>
     2849                        <li class="indline1"><tt>uri-host</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.21"><b>2.2</b></a></li>
     2850                        <li class="indline1"><tt>URI-reference</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.15"><b>2.2</b></a></li>
     2851                        <li class="indline1"><tt>value</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.41"><b>2.4</b></a></li>
     2852                        <li class="indline1"><tt>Via</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.90"><b>7.9</b></a></li>
     2853                        <li class="indline1"><tt>Via-v</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.91"><b>7.9</b></a></li>
     2854                        <li class="indline1"><tt>weekday</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.35"><b>2.3.1</b></a></li>
     2855                        <li class="indline1"><tt>wkday</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.34"><b>2.3.1</b></a></li>
    28572856                     </ul>
    28582857                  </li>
     
    28622861                  <li class="indline1">Headers&nbsp;&nbsp;
    28632862                     <ul class="ind">
    2864                         <li class="indline1">Connection&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.connection.1">4.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">7.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">7.1.3</a>, <a class="iref" href="#rfc.iref.h.3"><b>8.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">8.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">8.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">9.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li>
    2865                         <li class="indline1">Content-Length&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.content-length.1">4.4</a>, <a class="iref" href="#rfc.iref.h.4"><b>8.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">9.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li>
    2866                         <li class="indline1">Date&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.date.1">4.5</a>, <a class="iref" href="#rfc.iref.h.5"><b>8.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">9.1</a></li>
    2867                         <li class="indline1">Host&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.7"><b>8.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">9.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li>
    2868                         <li class="indline1">TE&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.te.1">3.4</a>, <a class="iref" href="#rfc.xref.header.te.2">3.4.1</a>, <a class="iref" href="#rfc.iref.h.8"><b>8.5</b></a>, <a class="iref" href="#rfc.xref.header.te.3">9.1</a>, <a class="iref" href="#rfc.xref.header.te.4">B.3</a></li>
    2869                         <li class="indline1">Trailer&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.trailer.1">3.4.1</a>, <a class="iref" href="#rfc.xref.header.trailer.2">4.5</a>, <a class="iref" href="#rfc.iref.h.9"><b>8.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">9.1</a></li>
    2870                         <li class="indline1">Transfer-Encoding&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.transfer-encoding.1">3.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">4.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">4.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">4.5</a>, <a class="iref" href="#rfc.iref.h.10"><b>8.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">9.1</a></li>
    2871                         <li class="indline1">Upgrade&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.upgrade.1">4.5</a>, <a class="iref" href="#rfc.iref.h.11"><b>8.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">9.1</a></li>
    2872                         <li class="indline1">Via&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.via.1">4.5</a>, <a class="iref" href="#rfc.iref.h.12"><b>8.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">9.1</a></li>
     2863                        <li class="indline1">Connection&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.connection.1">3.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">6.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">6.1.3</a>, <a class="iref" href="#rfc.iref.h.3"><b>7.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">7.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">7.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">8.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li>
     2864                        <li class="indline1">Content-Length&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.content-length.1">3.4</a>, <a class="iref" href="#rfc.iref.h.4"><b>7.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">8.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li>
     2865                        <li class="indline1">Date&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.date.1">3.5</a>, <a class="iref" href="#rfc.iref.h.5"><b>7.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">8.1</a></li>
     2866                        <li class="indline1">Host&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.7"><b>7.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">8.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li>
     2867                        <li class="indline1">TE&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.te.1">2.4</a>, <a class="iref" href="#rfc.xref.header.te.2">2.4.1</a>, <a class="iref" href="#rfc.iref.h.8"><b>7.5</b></a>, <a class="iref" href="#rfc.xref.header.te.3">8.1</a>, <a class="iref" href="#rfc.xref.header.te.4">B.3</a></li>
     2868                        <li class="indline1">Trailer&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.trailer.1">2.4.1</a>, <a class="iref" href="#rfc.xref.header.trailer.2">3.5</a>, <a class="iref" href="#rfc.iref.h.9"><b>7.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">8.1</a></li>
     2869                        <li class="indline1">Transfer-Encoding&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.transfer-encoding.1">2.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">3.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">3.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">3.5</a>, <a class="iref" href="#rfc.iref.h.10"><b>7.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">8.1</a></li>
     2870                        <li class="indline1">Upgrade&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.upgrade.1">3.5</a>, <a class="iref" href="#rfc.iref.h.11"><b>7.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">8.1</a></li>
     2871                        <li class="indline1">Via&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.via.1">3.5</a>, <a class="iref" href="#rfc.iref.h.12"><b>7.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">8.1</a></li>
    28732872                     </ul>
    28742873                  </li>
    2875                   <li class="indline1">Host header&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.6"><b>8.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">9.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li>
    2876                   <li class="indline1">http URI scheme&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.1"><b>3.2.1</b></a></li>
    2877                   <li class="indline1">https URI scheme&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.2">3.2.1</a></li>
     2874                  <li class="indline1">Host header&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.6"><b>7.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">8.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li>
     2875                  <li class="indline1">http URI scheme&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.1"><b>2.2.1</b></a></li>
     2876                  <li class="indline1">https URI scheme&nbsp;&nbsp;<a class="iref" href="#rfc.iref.h.2">2.2.1</a></li>
    28782877               </ul>
    28792878            </li>
    28802879            <li class="indline0"><a id="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul class="ind">
    28812880                  <li class="indline1">inbound&nbsp;&nbsp;<a class="iref" href="#rfc.iref.i.1">C</a></li>
    2882                   <li class="indline1"><em>ISO-8859-1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.ISO-8859-1.1">2.2</a>, <a class="iref" href="#ISO-8859-1"><b>12.1</b></a></li>
     2881                  <li class="indline1"><em>ISO-8859-1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.ISO-8859-1.1">1.2.2</a>, <a class="iref" href="#ISO-8859-1"><b>11.1</b></a></li>
    28832882               </ul>
    28842883            </li>
    28852884            <li class="indline0"><a id="rfc.index.K" href="#rfc.index.K"><b>K</b></a><ul class="ind">
    2886                   <li class="indline1"><em>Kri2001</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Kri2001.1">4.2</a>, <a class="iref" href="#Kri2001"><b>12.2</b></a></li>
     2885                  <li class="indline1"><em>Kri2001</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Kri2001.1">3.2</a>, <a class="iref" href="#Kri2001"><b>11.2</b></a></li>
    28872886               </ul>
    28882887            </li>
     
    28902889                  <li class="indline1">Media Type&nbsp;&nbsp;
    28912890                     <ul class="ind">
    2892                         <li class="indline1">application/http&nbsp;&nbsp;<a class="iref" href="#rfc.iref.m.3"><b>9.3.2</b></a></li>
    2893                         <li class="indline1">message/http&nbsp;&nbsp;<a class="iref" href="#rfc.iref.m.1"><b>9.3.1</b></a></li>
     2891                        <li class="indline1">application/http&nbsp;&nbsp;<a class="iref" href="#rfc.iref.m.3"><b>8.3.2</b></a></li>
     2892                        <li class="indline1">message/http&nbsp;&nbsp;<a class="iref" href="#rfc.iref.m.1"><b>8.3.1</b></a></li>
    28942893                     </ul>
    28952894                  </li>
    28962895                  <li class="indline1">message&nbsp;&nbsp;<a class="iref" href="#rfc.iref.m.4">C</a></li>
    2897                   <li class="indline1">message/http Media Type&nbsp;&nbsp;<a class="iref" href="#rfc.iref.m.2"><b>9.3.1</b></a></li>
     2896                  <li class="indline1">message/http Media Type&nbsp;&nbsp;<a class="iref" href="#rfc.iref.m.2"><b>8.3.1</b></a></li>
    28982897               </ul>
    28992898            </li>
    29002899            <li class="indline0"><a id="rfc.index.N" href="#rfc.index.N"><b>N</b></a><ul class="ind">
    2901                   <li class="indline1"><em>Nie1997</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Nie1997.1">7.1.1</a>, <a class="iref" href="#Nie1997"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.Nie1997.2">B.3</a></li>
     2900                  <li class="indline1"><em>Nie1997</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Nie1997.1">6.1.1</a>, <a class="iref" href="#Nie1997"><b>11.2</b></a>, <a class="iref" href="#rfc.xref.Nie1997.2">B.3</a></li>
    29022901               </ul>
    29032902            </li>
     
    29082907            </li>
    29092908            <li class="indline0"><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul class="ind">
    2910                   <li class="indline1"><em>Pad1995</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Pad1995.1">7.1.1</a>, <a class="iref" href="#Pad1995"><b>12.2</b></a></li>
    2911                   <li class="indline1"><em>Part2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.1">2.3</a>, <a class="iref" href="#rfc.xref.Part2.2">2.3</a>, <a class="iref" href="#rfc.xref.Part2.3">3.2</a>, <a class="iref" href="#rfc.xref.Part2.4">4.2</a>, <a class="iref" href="#rfc.xref.Part2.5">4.2</a>, <a class="iref" href="#rfc.xref.Part2.6">4.3</a>, <a class="iref" href="#rfc.xref.Part2.7">5</a>, <a class="iref" href="#rfc.xref.Part2.8">5.1.2</a>, <a class="iref" href="#rfc.xref.Part2.9">6</a>, <a class="iref" href="#rfc.xref.Part2.10">6.1.1</a>, <a class="iref" href="#rfc.xref.Part2.11">7.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.12">7.1.4</a>, <a class="iref" href="#rfc.xref.Part2.13">7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.14">7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.15">7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.16">7.2.3</a>, <a class="iref" href="#Part2"><b>12.1</b></a><ul class="ind">
    2912                         <li class="indline1"><em>Section 3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.6">4.3</a></li>
    2913                         <li class="indline1"><em>Section 4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.1">2.3</a>, <a class="iref" href="#rfc.xref.Part2.4">4.2</a>, <a class="iref" href="#rfc.xref.Part2.7">5</a></li>
    2914                         <li class="indline1"><em>Section 6</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.2">2.3</a>, <a class="iref" href="#rfc.xref.Part2.5">4.2</a>, <a class="iref" href="#rfc.xref.Part2.9">6</a></li>
    2915                         <li class="indline1"><em>Section 8.1.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.11">7.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.12">7.1.4</a></li>
    2916                         <li class="indline1"><em>Section 8.9</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.8">5.1.2</a></li>
    2917                         <li class="indline1"><em>Section 9</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.10">6.1.1</a></li>
    2918                         <li class="indline1"><em>Section 9.1.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.13">7.2.3</a></li>
    2919                         <li class="indline1"><em>Section 9.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.16">7.2.3</a></li>
    2920                         <li class="indline1"><em>Section 9.4.15</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.3">3.2</a></li>
    2921                         <li class="indline1"><em>Section 10.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.14">7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.15">7.2.3</a></li>
     2909                  <li class="indline1"><em>Pad1995</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Pad1995.1">6.1.1</a>, <a class="iref" href="#Pad1995"><b>11.2</b></a></li>
     2910                  <li class="indline1"><em>Part2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.3">2.2</a>, <a class="iref" href="#rfc.xref.Part2.4">3.2</a>, <a class="iref" href="#rfc.xref.Part2.5">3.2</a>, <a class="iref" href="#rfc.xref.Part2.6">3.3</a>, <a class="iref" href="#rfc.xref.Part2.7">4</a>, <a class="iref" href="#rfc.xref.Part2.8">4.1.2</a>, <a class="iref" href="#rfc.xref.Part2.9">5</a>, <a class="iref" href="#rfc.xref.Part2.10">5.1.1</a>, <a class="iref" href="#rfc.xref.Part2.11">6.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.12">6.1.4</a>, <a class="iref" href="#rfc.xref.Part2.13">6.2.3</a>, <a class="iref" href="#rfc.xref.Part2.14">6.2.3</a>, <a class="iref" href="#rfc.xref.Part2.15">6.2.3</a>, <a class="iref" href="#rfc.xref.Part2.16">6.2.3</a>, <a class="iref" href="#Part2"><b>11.1</b></a><ul class="ind">
     2911                        <li class="indline1"><em>Section 3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.6">3.3</a></li>
     2912                        <li class="indline1"><em>Section 4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.4">3.2</a>, <a class="iref" href="#rfc.xref.Part2.7">4</a></li>
     2913                        <li class="indline1"><em>Section 6</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.5">3.2</a>, <a class="iref" href="#rfc.xref.Part2.9">5</a></li>
     2914                        <li class="indline1"><em>Section 8.1.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.11">6.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.12">6.1.4</a></li>
     2915                        <li class="indline1"><em>Section 8.9</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.8">4.1.2</a></li>
     2916                        <li class="indline1"><em>Section 9</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.10">5.1.1</a></li>
     2917                        <li class="indline1"><em>Section 9.1.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.13">6.2.3</a></li>
     2918                        <li class="indline1"><em>Section 9.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.16">6.2.3</a></li>
     2919                        <li class="indline1"><em>Section 9.4.15</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.3">2.2</a></li>
     2920                        <li class="indline1"><em>Section 10.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part2.14">6.2.3</a>, <a class="iref" href="#rfc.xref.Part2.15">6.2.3</a></li>
    29222921                     </ul>
    29232922                  </li>
    2924                   <li class="indline1"><em>Part3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.1">1</a>, <a class="iref" href="#rfc.xref.Part3.2">1.2</a>, <a class="iref" href="#rfc.xref.Part3.3">2.2</a>, <a class="iref" href="#rfc.xref.Part3.4">2.3</a>, <a class="iref" href="#rfc.xref.Part3.5">2.3</a>, <a class="iref" href="#rfc.xref.Part3.6">2.3</a>, <a class="iref" href="#rfc.xref.Part3.7">3.4</a>, <a class="iref" href="#rfc.xref.Part3.8">3.4</a>, <a class="iref" href="#rfc.xref.Part3.9">4.2</a>, <a class="iref" href="#rfc.xref.Part3.10">5</a>, <a class="iref" href="#rfc.xref.Part3.11">6</a>, <a class="iref" href="#rfc.xref.Part3.12">8.5</a>, <a class="iref" href="#Part3"><b>12.1</b></a>, <a class="iref" href="#rfc.xref.Part3.13">A</a>, <a class="iref" href="#rfc.xref.Part3.14">B.3</a>, <a class="iref" href="#rfc.xref.Part3.15">C</a>, <a class="iref" href="#rfc.xref.Part3.16">C</a>, <a class="iref" href="#rfc.xref.Part3.17">C</a><ul class="ind">
    2925                         <li class="indline1"><em>Section 3.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.7">3.4</a>, <a class="iref" href="#rfc.xref.Part3.8">3.4</a></li>
    2926                         <li class="indline1"><em>Section 3.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.3">2.2</a></li>
    2927                         <li class="indline1"><em>Section 3.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.12">8.5</a></li>
    2928                         <li class="indline1"><em>Section 4.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.6">2.3</a>, <a class="iref" href="#rfc.xref.Part3.9">4.2</a>, <a class="iref" href="#rfc.xref.Part3.10">5</a>, <a class="iref" href="#rfc.xref.Part3.11">6</a></li>
     2923                  <li class="indline1"><em>Part3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.1">1</a>, <a class="iref" href="#rfc.xref.Part3.2">1.2.2</a>, <a class="iref" href="#rfc.xref.Part3.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.4">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.5">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.6">1.3</a>, <a class="iref" href="#rfc.xref.Part3.7">2.4</a>, <a class="iref" href="#rfc.xref.Part3.8">2.4</a>, <a class="iref" href="#rfc.xref.Part3.9">3.2</a>, <a class="iref" href="#rfc.xref.Part3.10">4</a>, <a class="iref" href="#rfc.xref.Part3.11">5</a>, <a class="iref" href="#rfc.xref.Part3.12">7.5</a>, <a class="iref" href="#Part3"><b>11.1</b></a>, <a class="iref" href="#rfc.xref.Part3.13">A</a>, <a class="iref" href="#rfc.xref.Part3.14">B.3</a>, <a class="iref" href="#rfc.xref.Part3.15">C</a>, <a class="iref" href="#rfc.xref.Part3.16">C</a>, <a class="iref" href="#rfc.xref.Part3.17">C</a><ul class="ind">
     2924                        <li class="indline1"><em>Section 3.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.7">2.4</a>, <a class="iref" href="#rfc.xref.Part3.8">2.4</a></li>
     2925                        <li class="indline1"><em>Section 3.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.2">1.2.2</a></li>
     2926                        <li class="indline1"><em>Section 3.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.12">7.5</a></li>
     2927                        <li class="indline1"><em>Section 4.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.5">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.9">3.2</a>, <a class="iref" href="#rfc.xref.Part3.10">4</a>, <a class="iref" href="#rfc.xref.Part3.11">5</a></li>
    29292928                        <li class="indline1"><em>Section 4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.15">C</a></li>
    2930                         <li class="indline1"><em>Section 4.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.5">2.3</a></li>
     2929                        <li class="indline1"><em>Section 4.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.4">1.2.3</a></li>
    29312930                        <li class="indline1"><em>Section 5</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.16">C</a>, <a class="iref" href="#rfc.xref.Part3.17">C</a></li>
    2932                         <li class="indline1"><em>Section 6.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.4">2.3</a></li>
    2933                         <li class="indline1"><em>Appendix A</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.1">1</a>, <a class="iref" href="#rfc.xref.Part3.2">1.2</a></li>
     2931                        <li class="indline1"><em>Section 6.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.3">1.2.3</a></li>
     2932                        <li class="indline1"><em>Appendix A</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part3.1">1</a>, <a class="iref" href="#rfc.xref.Part3.6">1.3</a></li>
    29342933                     </ul>
    29352934                  </li>
    2936                   <li class="indline1"><em>Part5</em>&nbsp;&nbsp;<a class="iref" href="#Part5"><b>12.1</b></a>, <a class="iref" href="#rfc.xref.Part5.1">B.3</a></li>
    2937                   <li class="indline1"><em>Part6</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.1">1.2</a>, <a class="iref" href="#rfc.xref.Part6.2">2.3</a>, <a class="iref" href="#rfc.xref.Part6.3">2.3</a>, <a class="iref" href="#rfc.xref.Part6.4">2.3</a>, <a class="iref" href="#rfc.xref.Part6.5">4.5</a>, <a class="iref" href="#rfc.xref.Part6.6">4.5</a>, <a class="iref" href="#rfc.xref.Part6.7">4.5</a>, <a class="iref" href="#Part6"><b>12.1</b></a>, <a class="iref" href="#rfc.xref.Part6.8">B.3</a>, <a class="iref" href="#rfc.xref.Part6.9">C</a><ul class="ind">
    2938                         <li class="indline1"><em>Section 1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.1">1.2</a>, <a class="iref" href="#rfc.xref.Part6.9">C</a></li>
    2939                         <li class="indline1"><em>Section 16.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.5">4.5</a></li>
    2940                         <li class="indline1"><em>Section 16.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.2">2.3</a>, <a class="iref" href="#rfc.xref.Part6.3">2.3</a>, <a class="iref" href="#rfc.xref.Part6.6">4.5</a></li>
    2941                         <li class="indline1"><em>Section 16.6</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.4">2.3</a>, <a class="iref" href="#rfc.xref.Part6.7">4.5</a></li>
     2935                  <li class="indline1"><em>Part5</em>&nbsp;&nbsp;<a class="iref" href="#Part5"><b>11.1</b></a>, <a class="iref" href="#rfc.xref.Part5.1">B.3</a></li>
     2936                  <li class="indline1"><em>Part6</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.4">1.3</a>, <a class="iref" href="#rfc.xref.Part6.5">3.5</a>, <a class="iref" href="#rfc.xref.Part6.6">3.5</a>, <a class="iref" href="#rfc.xref.Part6.7">3.5</a>, <a class="iref" href="#Part6"><b>11.1</b></a>, <a class="iref" href="#rfc.xref.Part6.8">B.3</a>, <a class="iref" href="#rfc.xref.Part6.9">C</a><ul class="ind">
     2937                        <li class="indline1"><em>Section 1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.4">1.3</a>, <a class="iref" href="#rfc.xref.Part6.9">C</a></li>
     2938                        <li class="indline1"><em>Section 16.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.5">3.5</a></li>
     2939                        <li class="indline1"><em>Section 16.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.6">3.5</a></li>
     2940                        <li class="indline1"><em>Section 16.6</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Part6.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.7">3.5</a></li>
    29422941                     </ul>
    29432942                  </li>
     
    29502949                  <li class="indline1">resource&nbsp;&nbsp;<a class="iref" href="#rfc.iref.r.3">C</a></li>
    29512950                  <li class="indline1">response&nbsp;&nbsp;<a class="iref" href="#rfc.iref.r.2">C</a></li>
    2952                   <li class="indline1"><em>RFC1123</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1123.1">3.3.1</a>, <a class="iref" href="#RFC1123"><b>12.2</b></a></li>
    2953                   <li class="indline1"><em>RFC1305</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1305.1">8.3</a>, <a class="iref" href="#RFC1305"><b>12.2</b></a></li>
    2954                   <li class="indline1"><em>RFC1436</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1436.1">1</a>, <a class="iref" href="#RFC1436"><b>12.2</b></a></li>
    2955                   <li class="indline1"><em>RFC1900</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1900.1">3.2.1</a>, <a class="iref" href="#rfc.xref.RFC1900.2">10.4</a>, <a class="iref" href="#RFC1900"><b>12.2</b></a></li>
    2956                   <li class="indline1"><em>RFC1945</em>&nbsp;&nbsp;<a class="iref" href="#RFC1945"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.RFC1945.1">B</a></li>
    2957                   <li class="indline1"><em>RFC2045</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2045.1">1</a>, <a class="iref" href="#rfc.xref.RFC2045.2">3.4</a>, <a class="iref" href="#rfc.xref.RFC2045.3">11</a>, <a class="iref" href="#RFC2045"><b>12.1</b></a></li>
    2958                   <li class="indline1"><em>RFC2047</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2047.1">2.2</a>, <a class="iref" href="#RFC2047"><b>12.1</b></a></li>
    2959                   <li class="indline1"><em>RFC2068</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2068.1">3.1</a>, <a class="iref" href="#rfc.xref.RFC2068.2">7.1.1</a>, <a class="iref" href="#rfc.xref.RFC2068.3">7.1.3</a>, <a class="iref" href="#rfc.xref.RFC2068.4">7.2.3</a>, <a class="iref" href="#rfc.xref.RFC2068.5">11</a>, <a class="iref" href="#RFC2068"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.RFC2068.6">B</a>, <a class="iref" href="#rfc.xref.RFC2068.7">B.2</a><ul class="ind">
     2951                  <li class="indline1"><em>RFC1123</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1123.1">2.3.1</a>, <a class="iref" href="#RFC1123"><b>11.2</b></a></li>
     2952                  <li class="indline1"><em>RFC1305</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1305.1">7.3</a>, <a class="iref" href="#RFC1305"><b>11.2</b></a></li>
     2953                  <li class="indline1"><em>RFC1436</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1436.1">1</a>, <a class="iref" href="#RFC1436"><b>11.2</b></a></li>
     2954                  <li class="indline1"><em>RFC1900</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC1900.1">2.2.1</a>, <a class="iref" href="#rfc.xref.RFC1900.2">9.4</a>, <a class="iref" href="#RFC1900"><b>11.2</b></a></li>
     2955                  <li class="indline1"><em>RFC1945</em>&nbsp;&nbsp;<a class="iref" href="#RFC1945"><b>11.2</b></a>, <a class="iref" href="#rfc.xref.RFC1945.1">B</a></li>
     2956                  <li class="indline1"><em>RFC2045</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2045.1">1</a>, <a class="iref" href="#rfc.xref.RFC2045.2">2.4</a>, <a class="iref" href="#rfc.xref.RFC2045.3">10</a>, <a class="iref" href="#RFC2045"><b>11.1</b></a></li>
     2957                  <li class="indline1"><em>RFC2047</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2047.1">1.2.2</a>, <a class="iref" href="#RFC2047"><b>11.1</b></a></li>
     2958                  <li class="indline1"><em>RFC2068</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2068.1">2.1</a>, <a class="iref" href="#rfc.xref.RFC2068.2">6.1.1</a>, <a class="iref" href="#rfc.xref.RFC2068.3">6.1.3</a>, <a class="iref" href="#rfc.xref.RFC2068.4">6.2.3</a>, <a class="iref" href="#rfc.xref.RFC2068.5">10</a>, <a class="iref" href="#RFC2068"><b>11.2</b></a>, <a class="iref" href="#rfc.xref.RFC2068.6">B</a>, <a class="iref" href="#rfc.xref.RFC2068.7">B.2</a><ul class="ind">
    29602959                        <li class="indline1"><em>Section 19.7.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2068.6">B</a></li>
    29612960                     </ul>
    29622961                  </li>
    2963                   <li class="indline1"><em>RFC2109</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2109.1">4.2</a>, <a class="iref" href="#RFC2109"><b>12.2</b></a></li>
    2964                   <li class="indline1"><em>RFC2119</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2119.1">1.1</a>, <a class="iref" href="#RFC2119"><b>12.1</b></a>, <a class="iref" href="#rfc.xref.RFC2119.2">B.3</a></li>
    2965                   <li class="indline1"><em>RFC2145</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2145.1">3.1</a>, <a class="iref" href="#rfc.xref.RFC2145.2">3.1</a>, <a class="iref" href="#RFC2145"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.RFC2145.3">B.3</a></li>
    2966                   <li class="indline1"><em>RFC2616</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2616.1">1</a>, <a class="iref" href="#rfc.xref.RFC2616.2">11</a>, <a class="iref" href="#RFC2616"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.RFC2616.3">D.1</a></li>
    2967                   <li class="indline1"><em>RFC2818</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2818.1">3.2.1</a>, <a class="iref" href="#RFC2818"><b>12.2</b></a></li>
    2968                   <li class="indline1"><em>RFC2965</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2965.1">4.2</a>, <a class="iref" href="#RFC2965"><b>12.2</b></a></li>
    2969                   <li class="indline1"><em>RFC3864</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3864.1">9.1</a>, <a class="iref" href="#RFC3864"><b>12.2</b></a></li>
    2970                   <li class="indline1"><em>RFC3977</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3977.1">1</a>, <a class="iref" href="#RFC3977"><b>12.2</b></a></li>
    2971                   <li class="indline1"><em>RFC3986</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.1">1</a>, <a class="iref" href="#rfc.xref.RFC3986.2">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.3">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.4">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.5">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.6">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.7">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.8">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.9">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.10">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.11">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.12">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.13">3.2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.14">5.1.2</a>, <a class="iref" href="#RFC3986"><b>12.1</b></a><ul class="ind">
    2972                         <li class="indline1"><em>Section 2.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.13">3.2.2</a></li>
    2973                         <li class="indline1"><em>Section 2.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.14">5.1.2</a></li>
    2974                         <li class="indline1"><em>Section 3.2.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.9">3.2</a></li>
    2975                         <li class="indline1"><em>Section 3.2.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.11">3.2</a></li>
    2976                         <li class="indline1"><em>Section 3.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.5">3.2</a></li>
    2977                         <li class="indline1"><em>Section 3.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.7">3.2</a>, <a class="iref" href="#rfc.xref.RFC3986.8">3.2</a></li>
    2978                         <li class="indline1"><em>Section 3.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.10">3.2</a></li>
    2979                         <li class="indline1"><em>Section 3.5</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.6">3.2</a></li>
    2980                         <li class="indline1"><em>Section 4.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.12">3.2</a></li>
    2981                         <li class="indline1"><em>Section 4.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.4">3.2</a></li>
     2962                  <li class="indline1"><em>RFC2109</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2109.1">3.2</a>, <a class="iref" href="#RFC2109"><b>11.2</b></a></li>
     2963                  <li class="indline1"><em>RFC2119</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2119.1">1.1</a>, <a class="iref" href="#RFC2119"><b>11.1</b></a>, <a class="iref" href="#rfc.xref.RFC2119.2">B.3</a></li>
     2964                  <li class="indline1"><em>RFC2145</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2145.1">2.1</a>, <a class="iref" href="#rfc.xref.RFC2145.2">2.1</a>, <a class="iref" href="#RFC2145"><b>11.2</b></a>, <a class="iref" href="#rfc.xref.RFC2145.3">B.3</a></li>
     2965                  <li class="indline1"><em>RFC2616</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2616.1">1</a>, <a class="iref" href="#rfc.xref.RFC2616.2">10</a>, <a class="iref" href="#RFC2616"><b>11.2</b></a>, <a class="iref" href="#rfc.xref.RFC2616.3">D.1</a></li>
     2966                  <li class="indline1"><em>RFC2818</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2818.1">2.2.1</a>, <a class="iref" href="#RFC2818"><b>11.2</b></a></li>
     2967                  <li class="indline1"><em>RFC2965</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC2965.1">3.2</a>, <a class="iref" href="#RFC2965"><b>11.2</b></a></li>
     2968                  <li class="indline1"><em>RFC3864</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3864.1">8.1</a>, <a class="iref" href="#RFC3864"><b>11.2</b></a></li>
     2969                  <li class="indline1"><em>RFC3977</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3977.1">1</a>, <a class="iref" href="#RFC3977"><b>11.2</b></a></li>
     2970                  <li class="indline1"><em>RFC3986</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.1">1</a>, <a class="iref" href="#rfc.xref.RFC3986.2">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.3">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.4">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.5">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.6">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.7">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.8">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.9">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.10">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.11">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.12">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.13">2.2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.14">4.1.2</a>, <a class="iref" href="#RFC3986"><b>11.1</b></a><ul class="ind">
     2971                        <li class="indline1"><em>Section 2.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.13">2.2.2</a></li>
     2972                        <li class="indline1"><em>Section 2.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.14">4.1.2</a></li>
     2973                        <li class="indline1"><em>Section 3.2.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.9">2.2</a></li>
     2974                        <li class="indline1"><em>Section 3.2.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.11">2.2</a></li>
     2975                        <li class="indline1"><em>Section 3.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.5">2.2</a></li>
     2976                        <li class="indline1"><em>Section 3.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.7">2.2</a>, <a class="iref" href="#rfc.xref.RFC3986.8">2.2</a></li>
     2977                        <li class="indline1"><em>Section 3.4</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.10">2.2</a></li>
     2978                        <li class="indline1"><em>Section 3.5</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.6">2.2</a></li>
     2979                        <li class="indline1"><em>Section 4.2</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.12">2.2</a></li>
     2980                        <li class="indline1"><em>Section 4.3</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC3986.4">2.2</a></li>
    29822981                     </ul>
    29832982                  </li>
    2984                   <li class="indline1"><em>RFC4288</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC4288.1">9.3</a>, <a class="iref" href="#RFC4288"><b>12.2</b></a></li>
    2985                   <li class="indline1"><em>RFC4395</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC4395.1">9.2</a>, <a class="iref" href="#RFC4395"><b>12.2</b></a></li>
    2986                   <li class="indline1"><em>RFC5234</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5234.1">2.1</a>, <a class="iref" href="#rfc.xref.RFC5234.2">2.2</a>, <a class="iref" href="#rfc.xref.RFC5234.3">2.2</a>, <a class="iref" href="#rfc.xref.RFC5234.4">11</a>, <a class="iref" href="#RFC5234"><b>12.1</b></a><ul class="ind">
    2987                         <li class="indline1"><em>Appendix B.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5234.3">2.2</a></li>
     2983                  <li class="indline1"><em>RFC4288</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC4288.1">8.3</a>, <a class="iref" href="#RFC4288"><b>11.2</b></a></li>
     2984                  <li class="indline1"><em>RFC4395</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC4395.1">8.2</a>, <a class="iref" href="#RFC4395"><b>11.2</b></a></li>
     2985                  <li class="indline1"><em>RFC5234</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5234.1">1.2.1</a>, <a class="iref" href="#rfc.xref.RFC5234.2">1.2.2</a>, <a class="iref" href="#rfc.xref.RFC5234.3">1.2.2</a>, <a class="iref" href="#rfc.xref.RFC5234.4">10</a>, <a class="iref" href="#RFC5234"><b>11.1</b></a><ul class="ind">
     2986                        <li class="indline1"><em>Appendix B.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5234.3">1.2.2</a></li>
    29882987                     </ul>
    29892988                  </li>
    2990                   <li class="indline1"><em>RFC5322</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.1">1</a>, <a class="iref" href="#rfc.xref.RFC5322.2">4.1</a>, <a class="iref" href="#rfc.xref.RFC5322.3">4.2</a>, <a class="iref" href="#rfc.xref.RFC5322.4">8.3</a>, <a class="iref" href="#rfc.xref.RFC5322.5">8.9</a>, <a class="iref" href="#RFC5322"><b>12.2</b></a><ul class="ind">
    2991                         <li class="indline1"><em>Section 2.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.3">4.2</a></li>
    2992                         <li class="indline1"><em>Section 3.6.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.4">8.3</a></li>
    2993                         <li class="indline1"><em>Section 3.6.7</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.5">8.9</a></li>
     2989                  <li class="indline1"><em>RFC5322</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.1">1</a>, <a class="iref" href="#rfc.xref.RFC5322.2">3.1</a>, <a class="iref" href="#rfc.xref.RFC5322.3">3.2</a>, <a class="iref" href="#rfc.xref.RFC5322.4">7.3</a>, <a class="iref" href="#rfc.xref.RFC5322.5">7.9</a>, <a class="iref" href="#RFC5322"><b>11.2</b></a><ul class="ind">
     2990                        <li class="indline1"><em>Section 2.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.3">3.2</a></li>
     2991                        <li class="indline1"><em>Section 3.6.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.4">7.3</a></li>
     2992                        <li class="indline1"><em>Section 3.6.7</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.5">7.9</a></li>
    29942993                     </ul>
    29952994                  </li>
    2996                   <li class="indline1"><em>RFC959</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC959.1">1</a>, <a class="iref" href="#RFC959"><b>12.2</b></a></li>
     2995                  <li class="indline1"><em>RFC959</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC959.1">1</a>, <a class="iref" href="#RFC959"><b>11.2</b></a></li>
    29972996               </ul>
    29982997            </li>
    29992998            <li class="indline0"><a id="rfc.index.S" href="#rfc.index.S"><b>S</b></a><ul class="ind">
    30002999                  <li class="indline1">server&nbsp;&nbsp;<a class="iref" href="#rfc.iref.s.1">C</a></li>
    3001                   <li class="indline1"><em>Spe</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Spe.1">7.1.1</a>, <a class="iref" href="#Spe"><b>12.2</b></a></li>
     3000                  <li class="indline1"><em>Spe</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Spe.1">6.1.1</a>, <a class="iref" href="#Spe"><b>11.2</b></a></li>
    30023001               </ul>
    30033002            </li>
    30043003            <li class="indline0"><a id="rfc.index.T" href="#rfc.index.T"><b>T</b></a><ul class="ind">
    3005                   <li class="indline1">TE header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.te.1">3.4</a>, <a class="iref" href="#rfc.xref.header.te.2">3.4.1</a>, <a class="iref" href="#rfc.iref.t.1"><b>8.5</b></a>, <a class="iref" href="#rfc.xref.header.te.3">9.1</a>, <a class="iref" href="#rfc.xref.header.te.4">B.3</a></li>
    3006                   <li class="indline1"><em>Tou1998</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Tou1998.1">7.1.1</a>, <a class="iref" href="#Tou1998"><b>12.2</b></a></li>
    3007                   <li class="indline1">Trailer header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.trailer.1">3.4.1</a>, <a class="iref" href="#rfc.xref.header.trailer.2">4.5</a>, <a class="iref" href="#rfc.iref.t.2"><b>8.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">9.1</a></li>
    3008                   <li class="indline1">Transfer-Encoding header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.transfer-encoding.1">3.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">4.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">4.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">4.5</a>, <a class="iref" href="#rfc.iref.t.3"><b>8.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">9.1</a></li>
     3004                  <li class="indline1">TE header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.te.1">2.4</a>, <a class="iref" href="#rfc.xref.header.te.2">2.4.1</a>, <a class="iref" href="#rfc.iref.t.1"><b>7.5</b></a>, <a class="iref" href="#rfc.xref.header.te.3">8.1</a>, <a class="iref" href="#rfc.xref.header.te.4">B.3</a></li>
     3005                  <li class="indline1"><em>Tou1998</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.Tou1998.1">6.1.1</a>, <a class="iref" href="#Tou1998"><b>11.2</b></a></li>
     3006                  <li class="indline1">Trailer header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.trailer.1">2.4.1</a>, <a class="iref" href="#rfc.xref.header.trailer.2">3.5</a>, <a class="iref" href="#rfc.iref.t.2"><b>7.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">8.1</a></li>
     3007                  <li class="indline1">Transfer-Encoding header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.transfer-encoding.1">2.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">3.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">3.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">3.5</a>, <a class="iref" href="#rfc.iref.t.3"><b>7.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">8.1</a></li>
    30093008                  <li class="indline1">tunnel&nbsp;&nbsp;<a class="iref" href="#rfc.iref.t.4">C</a></li>
    30103009               </ul>
    30113010            </li>
    30123011            <li class="indline0"><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul class="ind">
    3013                   <li class="indline1">Upgrade header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.upgrade.1">4.5</a>, <a class="iref" href="#rfc.iref.u.3"><b>8.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">9.1</a></li>
     3012                  <li class="indline1">Upgrade header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.upgrade.1">3.5</a>, <a class="iref" href="#rfc.iref.u.3"><b>7.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">8.1</a></li>
    30143013                  <li class="indline1">upstream&nbsp;&nbsp;<a class="iref" href="#rfc.iref.u.5">C</a></li>
    30153014                  <li class="indline1">URI scheme&nbsp;&nbsp;
    30163015                     <ul class="ind">
    3017                         <li class="indline1">http&nbsp;&nbsp;<a class="iref" href="#rfc.iref.u.1"><b>3.2.1</b></a></li>
    3018                         <li class="indline1">https&nbsp;&nbsp;<a class="iref" href="#rfc.iref.u.2">3.2.1</a></li>
     3016                        <li class="indline1">http&nbsp;&nbsp;<a class="iref" href="#rfc.iref.u.1"><b>2.2.1</b></a></li>
     3017                        <li class="indline1">https&nbsp;&nbsp;<a class="iref" href="#rfc.iref.u.2">2.2.1</a></li>
    30193018                     </ul>
    30203019                  </li>
    3021                   <li class="indline1"><em>USASCII</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.USASCII.1">2.2</a>, <a class="iref" href="#USASCII"><b>12.1</b></a></li>
     3020                  <li class="indline1"><em>USASCII</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.USASCII.1">1.2.2</a>, <a class="iref" href="#USASCII"><b>11.1</b></a></li>
    30223021                  <li class="indline1">user agent&nbsp;&nbsp;<a class="iref" href="#rfc.iref.u.4">C</a></li>
    30233022               </ul>
     
    30253024            <li class="indline0"><a id="rfc.index.V" href="#rfc.index.V"><b>V</b></a><ul class="ind">
    30263025                  <li class="indline1">variant&nbsp;&nbsp;<a class="iref" href="#rfc.iref.v.2">C</a></li>
    3027                   <li class="indline1">Via header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.via.1">4.5</a>, <a class="iref" href="#rfc.iref.v.1"><b>8.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">9.1</a></li>
     3026                  <li class="indline1">Via header&nbsp;&nbsp;<a class="iref" href="#rfc.xref.header.via.1">3.5</a>, <a class="iref" href="#rfc.iref.v.1"><b>7.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">8.1</a></li>
    30283027               </ul>
    30293028            </li>
    30303029            <li class="indline0"><a id="rfc.index.W" href="#rfc.index.W"><b>W</b></a><ul class="ind">
    3031                   <li class="indline1"><em>WAIS</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.WAIS.1">1</a>, <a class="iref" href="#WAIS"><b>12.2</b></a></li>
     3030                  <li class="indline1"><em>WAIS</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.WAIS.1">1</a>, <a class="iref" href="#WAIS"><b>11.2</b></a></li>
    30323031               </ul>
    30333032            </li>
  • draft-ietf-httpbis/latest/p1-messaging.xml

    r385 r389  
    280280</section>
    281281
    282 <section title="Overall Operation" anchor="intro.overall.operation">
    283 <t>
    284    HTTP is a request/response protocol. A client sends a
    285    request to the server in the form of a request method, URI, and
    286    protocol version, followed by a MIME-like message containing request
    287    modifiers, client information, and possible body content over a
    288    connection with a server. The server responds with a status line,
    289    including the message's protocol version and a success or error code,
    290    followed by a MIME-like message containing server information, entity
    291    metainformation, and possible entity-body content. The relationship
    292    between HTTP and MIME is described in &diff2045entity;.
    293 </t>
    294 <t>
    295    Most HTTP communication is initiated by a user agent and consists of
    296    a request to be applied to a resource on some origin server. In the
    297    simplest case, this may be accomplished via a single connection (v)
    298    between the user agent (UA) and the origin server (O).
    299 </t>
    300 <figure><artwork type="drawing">
    301        request chain ------------------------&gt;
    302     UA -------------------v------------------- O
    303        &lt;----------------------- response chain
    304 </artwork></figure>
    305 <t>
    306    A more complicated situation occurs when one or more intermediaries
    307    are present in the request/response chain. There are three common
    308    forms of intermediary: proxy, gateway, and tunnel. A proxy is a
    309    forwarding agent, receiving requests for a URI in its absolute form,
    310    rewriting all or part of the message, and forwarding the reformatted
    311    request toward the server identified by the URI. A gateway is a
    312    receiving agent, acting as a layer above some other server(s) and, if
    313    necessary, translating the requests to the underlying server's
    314    protocol. A tunnel acts as a relay point between two connections
    315    without changing the messages; tunnels are used when the
    316    communication needs to pass through an intermediary (such as a
    317    firewall) even when the intermediary cannot understand the contents
    318    of the messages.
    319 </t>
    320 <figure><artwork type="drawing">
    321        request chain --------------------------------------&gt;
    322     UA -----v----- A -----v----- B -----v----- C -----v----- O
    323        &lt;------------------------------------- response chain
    324 </artwork></figure>
    325 <t>
    326    The figure above shows three intermediaries (A, B, and C) between the
    327    user agent and origin server. A request or response message that
    328    travels the whole chain will pass through four separate connections.
    329    This distinction is important because some HTTP communication options
    330    may apply only to the connection with the nearest, non-tunnel
    331    neighbor, only to the end-points of the chain, or to all connections
    332    along the chain. Although the diagram is linear, each participant may
    333    be engaged in multiple, simultaneous communications. For example, B
    334    may be receiving requests from many clients other than A, and/or
    335    forwarding requests to servers other than C, at the same time that it
    336    is handling A's request.
    337 </t>
    338 <t>
    339    Any party to the communication which is not acting as a tunnel may
    340    employ an internal cache for handling requests. The effect of a cache
    341    is that the request/response chain is shortened if one of the
    342    participants along the chain has a cached response applicable to that
    343    request. The following illustrates the resulting chain if B has a
    344    cached copy of an earlier response from O (via C) for a request which
    345    has not been cached by UA or A.
    346 </t>
    347 <figure><artwork type="drawing">
    348           request chain ----------&gt;
    349        UA -----v----- A -----v----- B - - - - - - C - - - - - - O
    350           &lt;--------- response chain
    351 </artwork></figure>
    352 <t>
    353    Not all responses are usefully cacheable, and some requests may
    354    contain modifiers which place special requirements on cache behavior.
    355    HTTP requirements for cache behavior and cacheable responses are
    356    defined in &caching;.
    357 </t>
    358 <t>
    359    In fact, there are a wide variety of architectures and configurations
    360    of caches and proxies currently being experimented with or deployed
    361    across the World Wide Web. These systems include national hierarchies
    362    of proxy caches to save transoceanic bandwidth, systems that
    363    broadcast or multicast cache entries, organizations that distribute
    364    subsets of cached data via CD-ROM, and so on. HTTP systems are used
    365    in corporate intranets over high-bandwidth links, and for access via
    366    PDAs with low-power radio links and intermittent connectivity. The
    367    goal of HTTP/1.1 is to support the wide diversity of configurations
    368    already deployed while introducing protocol constructs that meet the
    369    needs of those who build web applications that require high
    370    reliability and, failing that, at least reliable indications of
    371    failure.
    372 </t>
    373 <t>
    374    HTTP communication usually takes place over TCP/IP connections. The
    375    default port is TCP 80 (<eref target="http://www.iana.org/assignments/port-numbers"/>), but other ports can be used. This does
    376    not preclude HTTP from being implemented on top of any other protocol
    377    on the Internet, or on other networks. HTTP only presumes a reliable
    378    transport; any protocol that provides such guarantees can be used;
    379    the mapping of the HTTP/1.1 request and response structures onto the
    380    transport data units of the protocol in question is outside the scope
    381    of this specification.
    382 </t>
    383 <t>
    384    In HTTP/1.0, most implementations used a new connection for each
    385    request/response exchange. In HTTP/1.1, a connection may be used for
    386    one or more request/response exchanges, although connections may be
    387    closed for a variety of reasons (see <xref target="persistent.connections"/>).
    388 </t>
    389 </section>
    390 </section>
    391 
    392282<section title="Notational Conventions and Generic Grammar" anchor="notation">
    393283
     
    600490
    601491</section>
     492
     493<section title="Overall Operation" anchor="intro.overall.operation">
     494<t>
     495   HTTP is a request/response protocol. A client sends a
     496   request to the server in the form of a request method, URI, and
     497   protocol version, followed by a MIME-like message containing request
     498   modifiers, client information, and possible body content over a
     499   connection with a server. The server responds with a status line,
     500   including the message's protocol version and a success or error code,
     501   followed by a MIME-like message containing server information, entity
     502   metainformation, and possible entity-body content. The relationship
     503   between HTTP and MIME is described in &diff2045entity;.
     504</t>
     505<t>
     506   Most HTTP communication is initiated by a user agent and consists of
     507   a request to be applied to a resource on some origin server. In the
     508   simplest case, this may be accomplished via a single connection (v)
     509   between the user agent (UA) and the origin server (O).
     510</t>
     511<figure><artwork type="drawing">
     512       request chain ------------------------&gt;
     513    UA -------------------v------------------- O
     514       &lt;----------------------- response chain
     515</artwork></figure>
     516<t>
     517   A more complicated situation occurs when one or more intermediaries
     518   are present in the request/response chain. There are three common
     519   forms of intermediary: proxy, gateway, and tunnel. A proxy is a
     520   forwarding agent, receiving requests for a URI in its absolute form,
     521   rewriting all or part of the message, and forwarding the reformatted
     522   request toward the server identified by the URI. A gateway is a
     523   receiving agent, acting as a layer above some other server(s) and, if
     524   necessary, translating the requests to the underlying server's
     525   protocol. A tunnel acts as a relay point between two connections
     526   without changing the messages; tunnels are used when the
     527   communication needs to pass through an intermediary (such as a
     528   firewall) even when the intermediary cannot understand the contents
     529   of the messages.
     530</t>
     531<figure><artwork type="drawing">
     532       request chain --------------------------------------&gt;
     533    UA -----v----- A -----v----- B -----v----- C -----v----- O
     534       &lt;------------------------------------- response chain
     535</artwork></figure>
     536<t>
     537   The figure above shows three intermediaries (A, B, and C) between the
     538   user agent and origin server. A request or response message that
     539   travels the whole chain will pass through four separate connections.
     540   This distinction is important because some HTTP communication options
     541   may apply only to the connection with the nearest, non-tunnel
     542   neighbor, only to the end-points of the chain, or to all connections
     543   along the chain. Although the diagram is linear, each participant may
     544   be engaged in multiple, simultaneous communications. For example, B
     545   may be receiving requests from many clients other than A, and/or
     546   forwarding requests to servers other than C, at the same time that it
     547   is handling A's request.
     548</t>
     549<t>
     550   Any party to the communication which is not acting as a tunnel may
     551   employ an internal cache for handling requests. The effect of a cache
     552   is that the request/response chain is shortened if one of the
     553   participants along the chain has a cached response applicable to that
     554   request. The following illustrates the resulting chain if B has a
     555   cached copy of an earlier response from O (via C) for a request which
     556   has not been cached by UA or A.
     557</t>
     558<figure><artwork type="drawing">
     559          request chain ----------&gt;
     560       UA -----v----- A -----v----- B - - - - - - C - - - - - - O
     561          &lt;--------- response chain
     562</artwork></figure>
     563<t>
     564   Not all responses are usefully cacheable, and some requests may
     565   contain modifiers which place special requirements on cache behavior.
     566   HTTP requirements for cache behavior and cacheable responses are
     567   defined in &caching;.
     568</t>
     569<t>
     570   In fact, there are a wide variety of architectures and configurations
     571   of caches and proxies currently being experimented with or deployed
     572   across the World Wide Web. These systems include national hierarchies
     573   of proxy caches to save transoceanic bandwidth, systems that
     574   broadcast or multicast cache entries, organizations that distribute
     575   subsets of cached data via CD-ROM, and so on. HTTP systems are used
     576   in corporate intranets over high-bandwidth links, and for access via
     577   PDAs with low-power radio links and intermittent connectivity. The
     578   goal of HTTP/1.1 is to support the wide diversity of configurations
     579   already deployed while introducing protocol constructs that meet the
     580   needs of those who build web applications that require high
     581   reliability and, failing that, at least reliable indications of
     582   failure.
     583</t>
     584<t>
     585   HTTP communication usually takes place over TCP/IP connections. The
     586   default port is TCP 80 (<eref target="http://www.iana.org/assignments/port-numbers"/>), but other ports can be used. This does
     587   not preclude HTTP from being implemented on top of any other protocol
     588   on the Internet, or on other networks. HTTP only presumes a reliable
     589   transport; any protocol that provides such guarantees can be used;
     590   the mapping of the HTTP/1.1 request and response structures onto the
     591   transport data units of the protocol in question is outside the scope
     592   of this specification.
     593</t>
     594<t>
     595   In HTTP/1.0, most implementations used a new connection for each
     596   request/response exchange. In HTTP/1.1, a connection may be used for
     597   one or more request/response exchanges, although connections may be
     598   closed for a variety of reasons (see <xref target="persistent.connections"/>).
     599</t>
     600</section>
     601</section>
     602
    602603
    603604<section title="Protocol Parameters" anchor="protocol.parameters">
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