source: draft-ietf-httpbis/latest/p5-range.html @ 1804

Last change on this file since 1804 was 1804, checked in by julian.reschke@…, 7 years ago

remove pre-WGLC changelog

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445       content: "HTTP/1.1, Part 5"; 
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448       content: "Fielding, et al."; 
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469</style><link rel="Contents" href="#rfc.toc">
470      <link rel="Author" href="#rfc.authors">
471      <link rel="Copyright" href="#rfc.copyrightnotice">
472      <link rel="Index" href="#rfc.index">
473      <link rel="Chapter" title="1 Introduction" href="#rfc.section.1">
474      <link rel="Chapter" title="2 Range Units" href="#rfc.section.2">
475      <link rel="Chapter" title="3 Status Code Definitions" href="#rfc.section.3">
476      <link rel="Chapter" title="4 Responses to a Range Request" href="#rfc.section.4">
477      <link rel="Chapter" title="5 Header Field Definitions" href="#rfc.section.5">
478      <link rel="Chapter" title="6 IANA Considerations" href="#rfc.section.6">
479      <link rel="Chapter" title="7 Security Considerations" href="#rfc.section.7">
480      <link rel="Chapter" title="8 Acknowledgments" href="#rfc.section.8">
481      <link rel="Chapter" href="#rfc.section.9" title="9 References">
482      <link rel="Appendix" title="A Internet Media Type multipart/byteranges" href="#rfc.section.A">
483      <link rel="Appendix" title="B Changes from RFC 2616" href="#rfc.section.B">
484      <link rel="Appendix" title="C Collected ABNF" href="#rfc.section.C">
485      <link rel="Appendix" title="D Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.D">
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489      <link rel="schema.dct" href="http://purl.org/dc/terms/">
490      <meta name="dct.creator" content="Fielding, R.">
491      <meta name="dct.creator" content="Lafon, Y.">
492      <meta name="dct.creator" content="Reschke, J. F.">
493      <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p5-range-latest">
494      <meta name="dct.issued" scheme="ISO8601" content="2012-07-16">
495      <meta name="dct.replaces" content="urn:ietf:rfc:2616">
496      <meta name="dct.abstract" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypertext information systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 5 of the seven-part specification that defines the protocol referred to as &#34;HTTP/1.1&#34; and, taken together, obsoletes RFC 2616. Part 5 defines range requests and the rules for constructing and combining responses to those requests.">
497      <meta name="description" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypertext information systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 5 of the seven-part specification that defines the protocol referred to as &#34;HTTP/1.1&#34; and, taken together, obsoletes RFC 2616. Part 5 defines range requests and the rules for constructing and combining responses to those requests.">
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500      <table class="header">
501         <tbody>
502            <tr>
503               <td class="left">HTTPbis Working Group</td>
504               <td class="right">R. Fielding, Editor</td>
505            </tr>
506            <tr>
507               <td class="left">Internet-Draft</td>
508               <td class="right">Adobe</td>
509            </tr>
510            <tr>
511               <td class="left">Obsoletes: <a href="http://tools.ietf.org/html/rfc2616">2616</a> (if approved)
512               </td>
513               <td class="right">Y. Lafon, Editor</td>
514            </tr>
515            <tr>
516               <td class="left">Intended status: Standards Track</td>
517               <td class="right">W3C</td>
518            </tr>
519            <tr>
520               <td class="left">Expires: January 17, 2013</td>
521               <td class="right">J. Reschke, Editor</td>
522            </tr>
523            <tr>
524               <td class="left"></td>
525               <td class="right">greenbytes</td>
526            </tr>
527            <tr>
528               <td class="left"></td>
529               <td class="right">July 16, 2012</td>
530            </tr>
531         </tbody>
532      </table>
533      <p class="title">HTTP/1.1, part 5: Range Requests<br><span class="filename">draft-ietf-httpbis-p5-range-latest</span></p>
534      <h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1> 
535      <p>The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypertext information
536         systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 5 of the
537         seven-part specification that defines the protocol referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
538      </p> 
539      <p>Part 5 defines range requests and the rules for constructing and combining responses to those requests.</p> 
540      <h1 id="rfc.note.1"><a href="#rfc.note.1">Editorial Note (To be removed by RFC Editor)</a></h1> 
541      <p>Discussion of this draft takes place on the HTTPBIS working group mailing list (ietf-http-wg@w3.org), which is archived at &lt;<a href="http://lists.w3.org/Archives/Public/ietf-http-wg/">http://lists.w3.org/Archives/Public/ietf-http-wg/</a>&gt;.
542      </p> 
543      <p>The current issues list is at &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/report/3">http://tools.ietf.org/wg/httpbis/trac/report/3</a>&gt; and related documents (including fancy diffs) can be found at &lt;<a href="http://tools.ietf.org/wg/httpbis/">http://tools.ietf.org/wg/httpbis/</a>&gt;.
544      </p> 
545      <p>The changes in this draft are summarized in <a href="#changes.since.19" title="Since draft-ietf-httpbis-p5-range-19">Appendix&nbsp;D.1</a>.
546      </p> 
547      <h1><a id="rfc.status" href="#rfc.status">Status of This Memo</a></h1>
548      <p>This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.</p>
549      <p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute
550         working documents as Internet-Drafts. The list of current Internet-Drafts is at <a href="http://datatracker.ietf.org/drafts/current/">http://datatracker.ietf.org/drafts/current/</a>.
551      </p>
552      <p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other
553         documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work
554         in progress”.
555      </p>
556      <p>This Internet-Draft will expire on January 17, 2013.</p>
557      <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1>
558      <p>Copyright © 2012 IETF Trust and the persons identified as the document authors. All rights reserved.</p>
559      <p>This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights
560         and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License
561         text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified
562         BSD License.
563      </p>
564      <p>This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November
565         10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to
566         allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s)
567         controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative
568         works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate
569         it into languages other than English.
570      </p>
571      <hr class="noprint">
572      <h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1>
573      <ul class="toc">
574         <li>1.&nbsp;&nbsp;&nbsp;<a href="#introduction">Introduction</a><ul>
575               <li>1.1&nbsp;&nbsp;&nbsp;<a href="#intro.conformance.and.error.handling">Conformance and Error Handling</a></li>
576               <li>1.2&nbsp;&nbsp;&nbsp;<a href="#notation">Syntax Notation</a><ul>
577                     <li>1.2.1&nbsp;&nbsp;&nbsp;<a href="#core.rules">Core Rules</a></li>
578                     <li>1.2.2&nbsp;&nbsp;&nbsp;<a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></li>
579                  </ul>
580               </li>
581            </ul>
582         </li>
583         <li>2.&nbsp;&nbsp;&nbsp;<a href="#range.units">Range Units</a><ul>
584               <li>2.1&nbsp;&nbsp;&nbsp;<a href="#range.specifier.registry">Range Specifier Registry</a></li>
585            </ul>
586         </li>
587         <li>3.&nbsp;&nbsp;&nbsp;<a href="#status.code.definitions">Status Code Definitions</a><ul>
588               <li>3.1&nbsp;&nbsp;&nbsp;<a href="#status.206">206 Partial Content</a></li>
589               <li>3.2&nbsp;&nbsp;&nbsp;<a href="#status.416">416 Requested Range Not Satisfiable</a></li>
590            </ul>
591         </li>
592         <li>4.&nbsp;&nbsp;&nbsp;<a href="#rfc.section.4">Responses to a Range Request</a><ul>
593               <li>4.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.4.1">Response to a Single and Multiple Ranges Request</a></li>
594               <li>4.2&nbsp;&nbsp;&nbsp;<a href="#combining.byte.ranges">Combining Ranges</a></li>
595            </ul>
596         </li>
597         <li>5.&nbsp;&nbsp;&nbsp;<a href="#header.field.definitions">Header Field Definitions</a><ul>
598               <li>5.1&nbsp;&nbsp;&nbsp;<a href="#header.accept-ranges">Accept-Ranges</a></li>
599               <li>5.2&nbsp;&nbsp;&nbsp;<a href="#header.content-range">Content-Range</a></li>
600               <li>5.3&nbsp;&nbsp;&nbsp;<a href="#header.if-range">If-Range</a></li>
601               <li>5.4&nbsp;&nbsp;&nbsp;<a href="#header.range">Range</a><ul>
602                     <li>5.4.1&nbsp;&nbsp;&nbsp;<a href="#byte.ranges">Byte Ranges</a></li>
603                     <li>5.4.2&nbsp;&nbsp;&nbsp;<a href="#range.retrieval.requests">Range Retrieval Requests</a></li>
604                  </ul>
605               </li>
606            </ul>
607         </li>
608         <li>6.&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
609               <li>6.1&nbsp;&nbsp;&nbsp;<a href="#status.code.registration">Status Code Registration</a></li>
610               <li>6.2&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Header Field Registration</a></li>
611               <li>6.3&nbsp;&nbsp;&nbsp;<a href="#range.specifier.registration">Range Specifier Registration</a></li>
612            </ul>
613         </li>
614         <li>7.&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul>
615               <li>7.1&nbsp;&nbsp;&nbsp;<a href="#overlapping.ranges">Overlapping Ranges</a></li>
616            </ul>
617         </li>
618         <li>8.&nbsp;&nbsp;&nbsp;<a href="#acks">Acknowledgments</a></li>
619         <li>9.&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
620               <li>9.1&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
621               <li>9.2&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
622            </ul>
623         </li>
624         <li><a href="#rfc.authors">Authors' Addresses</a></li>
625         <li>A.&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.multipart.byteranges">Internet Media Type multipart/byteranges</a></li>
626         <li>B.&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616">Changes from RFC 2616</a></li>
627         <li>C.&nbsp;&nbsp;&nbsp;<a href="#collected.abnf">Collected ABNF</a></li>
628         <li>D.&nbsp;&nbsp;&nbsp;<a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul>
629               <li>D.1&nbsp;&nbsp;&nbsp;<a href="#changes.since.19">Since draft-ietf-httpbis-p5-range-19</a></li>
630            </ul>
631         </li>
632         <li><a href="#rfc.index">Index</a></li>
633      </ul>
634      <h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a>&nbsp;<a id="introduction" href="#introduction">Introduction</a></h1>
635      <p id="rfc.section.1.p.1">HTTP clients often encounter interrupted data transfers as a result of canceled requests or dropped connections. When a client
636         has stored a partial representation, it is desirable to request the remainder of that representation in a subsequent request
637         rather than transfer the entire representation. There are also a number of Web applications that benefit from being able to
638         request only a subset of a larger representation, such as a single page of a very large document or only part of an image
639         to be rendered by a device with limited local storage.
640      </p>
641      <p id="rfc.section.1.p.2">This document defines HTTP/1.1 range requests, partial responses, and the multipart/byteranges media type. The protocol for
642         range requests is an <em class="bcp14">OPTIONAL</em> feature of HTTP, designed so resources or recipients that do not implement this feature can respond as if it is a normal GET
643         request without impacting interoperability. Partial responses are indicated by a distinct status code to not be mistaken for
644         full responses by intermediate caches that might not implement the feature.
645      </p>
646      <p id="rfc.section.1.p.3">Although the HTTP range request mechanism is designed to allow for extensible range types, this specification only defines
647         requests for byte ranges.
648      </p>
649      <h2 id="rfc.section.1.1"><a href="#rfc.section.1.1">1.1</a>&nbsp;<a id="intro.conformance.and.error.handling" href="#intro.conformance.and.error.handling">Conformance and Error Handling</a></h2>
650      <p id="rfc.section.1.1.p.1">The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
651         in this document are to be interpreted as described in <a href="#RFC2119" id="rfc.xref.RFC2119.1"><cite title="Key words for use in RFCs to Indicate Requirement Levels">[RFC2119]</cite></a>.
652      </p>
653      <p id="rfc.section.1.1.p.2">This specification targets conformance criteria according to the role of a participant in HTTP communication. Hence, HTTP
654         requirements are placed on senders, recipients, clients, servers, user agents, intermediaries, origin servers, proxies, gateways,
655         or caches, depending on what behavior is being constrained by the requirement. See <a href="p1-messaging.html#architecture" title="Architecture">Section 2</a> of <a href="#Part1" id="rfc.xref.Part1.1"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a> for definitions of these terms.
656      </p>
657      <p id="rfc.section.1.1.p.3">The verb "generate" is used instead of "send" where a requirement differentiates between creating a protocol element and merely
658         forwarding a received element downstream.
659      </p>
660      <p id="rfc.section.1.1.p.4">An implementation is considered conformant if it complies with all of the requirements associated with the roles it partakes
661         in HTTP. Note that SHOULD-level requirements are relevant here, unless one of the documented exceptions is applicable.
662      </p>
663      <p id="rfc.section.1.1.p.5">This document also uses ABNF to define valid protocol elements (<a href="#notation" title="Syntax Notation">Section&nbsp;1.2</a>). In addition to the prose requirements placed upon them, senders <em class="bcp14">MUST NOT</em> generate protocol elements that do not match the grammar defined by the ABNF rules for those protocol elements that are applicable
664         to the sender's role. If a received protocol element is processed, the recipient <em class="bcp14">MUST</em> be able to parse any value that would match the ABNF rules for that protocol element, excluding only those rules not applicable
665         to the recipient's role.
666      </p>
667      <p id="rfc.section.1.1.p.6">Unless noted otherwise, a recipient <em class="bcp14">MAY</em> attempt to recover a usable protocol element from an invalid construct. HTTP does not define specific error handling mechanisms
668         except when they have a direct impact on security, since different applications of the protocol require different error handling
669         strategies. For example, a Web browser might wish to transparently recover from a response where the <a href="p2-semantics.html#header.location" class="smpl">Location</a> header field doesn't parse according to the ABNF, whereas a systems control client might consider any form of error recovery
670         to be dangerous.
671      </p>
672      <h2 id="rfc.section.1.2"><a href="#rfc.section.1.2">1.2</a>&nbsp;<a id="notation" href="#notation">Syntax Notation</a></h2>
673      <p id="rfc.section.1.2.p.1">This specification uses the Augmented Backus-Naur Form (ABNF) notation of <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> with the list rule extension defined in <a href="p1-messaging.html#notation" title="Syntax Notation">Section 1.2</a> of <a href="#Part1" id="rfc.xref.Part1.2"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>. <a href="#collected.abnf" title="Collected ABNF">Appendix&nbsp;C</a> shows the collected ABNF with the list rule expanded.
674      </p>
675      <p id="rfc.section.1.2.p.2">The following core rules are included by reference, as defined in <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, <a href="http://tools.ietf.org/html/rfc5234#appendix-B.1">Appendix B.1</a>: ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote), HEXDIG
676         (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit sequence of data), SP (space), and VCHAR (any visible US-ASCII
677         character).
678      </p>
679      <p id="rfc.section.1.2.p.3">Note that all rules derived from <a href="#core.rules" class="smpl">token</a> are to be compared case-insensitively, like <a href="#range.units" class="smpl">range-unit</a> and <a href="#header.accept-ranges" class="smpl">acceptable-ranges</a>.
680      </p>
681      <h3 id="rfc.section.1.2.1"><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;<a id="core.rules" href="#core.rules">Core Rules</a></h3>
682      <p id="rfc.section.1.2.1.p.1">The core rules below are defined in <a href="#Part1" id="rfc.xref.Part1.3"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a> and <a href="#Part2" id="rfc.xref.Part2.1"><cite title="HTTP/1.1, part 2: Semantics and Payloads">[Part2]</cite></a>:
683      </p>
684      <div id="rfc.figure.u.1"></div><pre class="inline">  <a href="#core.rules" class="smpl">OWS</a>        = &lt;OWS, defined in <a href="#Part1" id="rfc.xref.Part1.4"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>, <a href="p1-messaging.html#whitespace" title="Whitespace">Section 3.2.1</a>&gt;
685  <a href="#core.rules" class="smpl">token</a>      = &lt;token, defined in <a href="#Part1" id="rfc.xref.Part1.5"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>, <a href="p1-messaging.html#field.components" title="Field value components">Section 3.2.4</a>&gt;
686  <a href="#core.rules" class="smpl">HTTP-date</a>  = &lt;HTTP-date, defined in <a href="#Part2" id="rfc.xref.Part2.2"><cite title="HTTP/1.1, part 2: Semantics and Payloads">[Part2]</cite></a>, <a href="p2-semantics.html#http.date" title="Date/Time Formats">Section 5.1</a>&gt;
687</pre><h3 id="rfc.section.1.2.2"><a href="#rfc.section.1.2.2">1.2.2</a>&nbsp;<a id="abnf.dependencies" href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></h3>
688      <p id="rfc.section.1.2.2.p.1">The ABNF rules below are defined in other parts:</p>
689      <div id="rfc.figure.u.2"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">entity-tag</a> = &lt;entity-tag, defined in <a href="#Part4" id="rfc.xref.Part4.1"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>, <a href="p4-conditional.html#header.etag" title="ETag">Section 2.3</a>&gt;
690</pre><h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a id="range.units" href="#range.units">Range Units</a></h1>
691      <p id="rfc.section.2.p.1">HTTP/1.1 allows a client to request that only part (a range) of the representation be included within the response. HTTP/1.1
692         uses range units in the <a href="#range.retrieval.requests" class="smpl">Range</a> (<a href="#header.range" id="rfc.xref.header.range.1" title="Range">Section&nbsp;5.4</a>) and <a href="#header.content-range" class="smpl">Content-Range</a> (<a href="#header.content-range" id="rfc.xref.header.content-range.1" title="Content-Range">Section&nbsp;5.2</a>) header fields. A representation can be broken down into subranges according to various structural units.
693      </p>
694      <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="#range.units" class="smpl">range-unit</a>       = <a href="#range.units" class="smpl">bytes-unit</a> / <a href="#range.units" class="smpl">other-range-unit</a>
695  <a href="#range.units" class="smpl">bytes-unit</a>       = "bytes"
696  <a href="#range.units" class="smpl">other-range-unit</a> = <a href="#core.rules" class="smpl">token</a>
697</pre><p id="rfc.section.2.p.3">HTTP/1.1 has been designed to allow implementations of applications that do not depend on knowledge of ranges. The only range
698         unit defined by HTTP/1.1 is "bytes". Additional specifiers can be defined as described in <a href="#range.specifier.registry" title="Range Specifier Registry">Section&nbsp;2.1</a>.
699      </p>
700      <p id="rfc.section.2.p.4">If a range unit is not understood in a request, a server <em class="bcp14">MUST</em> ignore the whole <a href="#range.retrieval.requests" class="smpl">Range</a> header field (<a href="#header.range" id="rfc.xref.header.range.2" title="Range">Section&nbsp;5.4</a>). If a range unit is not understood in a response, an intermediary <em class="bcp14">SHOULD</em> pass the response to the client; a client <em class="bcp14">MUST</em> fail.
701      </p>
702      <h2 id="rfc.section.2.1"><a href="#rfc.section.2.1">2.1</a>&nbsp;<a id="range.specifier.registry" href="#range.specifier.registry">Range Specifier Registry</a></h2>
703      <p id="rfc.section.2.1.p.1">The HTTP Range Specifier Registry defines the name space for the range specifier names.</p>
704      <p id="rfc.section.2.1.p.2">Registrations <em class="bcp14">MUST</em> include the following fields:
705      </p>
706      <ul>
707         <li>Name</li>
708         <li>Description</li>
709         <li>Pointer to specification text</li>
710      </ul>
711      <p id="rfc.section.2.1.p.3">Values to be added to this name space require IETF Review (see <a href="#RFC5226" id="rfc.xref.RFC5226.1"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
712      </p>
713      <p id="rfc.section.2.1.p.4">The registry itself is maintained at &lt;<a href="http://www.iana.org/assignments/http-range-specifiers">http://www.iana.org/assignments/http-range-specifiers</a>&gt;.
714      </p>
715      <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a>&nbsp;<a id="status.code.definitions" href="#status.code.definitions">Status Code Definitions</a></h1>
716      <div id="rfc.iref.3"></div>
717      <div id="rfc.iref.s.1"></div>
718      <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a>&nbsp;<a id="status.206" href="#status.206">206 Partial Content</a></h2>
719      <p id="rfc.section.3.1.p.1">The server has fulfilled the partial GET request for the resource. The request <em class="bcp14">MUST</em> have included a <a href="#range.retrieval.requests" class="smpl">Range</a> header field (<a href="#header.range" id="rfc.xref.header.range.3" title="Range">Section&nbsp;5.4</a>) indicating the desired range, and <em class="bcp14">MAY</em> have included an <a href="#header.if-range" class="smpl">If-Range</a> header field (<a href="#header.if-range" id="rfc.xref.header.if-range.1" title="If-Range">Section&nbsp;5.3</a>) to make the request conditional.
720      </p>
721      <p id="rfc.section.3.1.p.2">The response <em class="bcp14">MUST</em> include the following header fields:
722      </p>
723      <ul>
724         <li>Either a <a href="#header.content-range" class="smpl">Content-Range</a> header field (<a href="#header.content-range" id="rfc.xref.header.content-range.2" title="Content-Range">Section&nbsp;5.2</a>) indicating the range included with this response, or a multipart/byteranges <a href="p2-semantics.html#header.content-type" class="smpl">Content-Type</a> including Content-Range fields for each part. If a <a href="p1-messaging.html#header.content-length" class="smpl">Content-Length</a> header field is present in the response, its value <em class="bcp14">MUST</em> match the actual number of octets transmitted in the message body.
725         </li>
726         <li>Date</li>
727         <li> <a href="p6-cache.html#header.cache-control" class="smpl">Cache-Control</a>, <a href="p4-conditional.html#header.etag" class="smpl">ETag</a>, <a href="p6-cache.html#header.expires" class="smpl">Expires</a>, <a href="p2-semantics.html#header.content-location" class="smpl">Content-Location</a> and/or <a href="p6-cache.html#header.vary" class="smpl">Vary</a>, if the header field would have been sent in a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response to the same request
728         </li>
729      </ul>
730      <p id="rfc.section.3.1.p.3">If a 206 is sent in response to a request with an <a href="#header.if-range" class="smpl">If-Range</a> header field, it <em class="bcp14">SHOULD NOT</em> include other representation header fields. Otherwise, the response <em class="bcp14">MUST</em> include all of the representation header fields that would have been returned with a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response to the same request.
731      </p>
732      <p id="rfc.section.3.1.p.4">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 206 responses.
733      </p>
734      <div id="rfc.iref.4"></div>
735      <div id="rfc.iref.s.2"></div>
736      <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a>&nbsp;<a id="status.416" href="#status.416">416 Requested Range Not Satisfiable</a></h2>
737      <p id="rfc.section.3.2.p.1">A server <em class="bcp14">SHOULD</em> return a response with this status code if a request included a <a href="#range.retrieval.requests" class="smpl">Range</a> header field (<a href="#header.range" id="rfc.xref.header.range.4" title="Range">Section&nbsp;5.4</a>), and none of the ranges-specifier values in this field overlap the current extent of the selected resource, and the request
738         did not include an <a href="#header.if-range" class="smpl">If-Range</a> header field (<a href="#header.if-range" id="rfc.xref.header.if-range.2" title="If-Range">Section&nbsp;5.3</a>). (For byte-ranges, this means that the first-byte-pos of all of the byte-range-spec values were greater than the current
739         length of the selected resource.)
740      </p>
741      <p id="rfc.section.3.2.p.2">When this status code is returned for a byte-range request, the response <em class="bcp14">SHOULD</em> include a <a href="#header.content-range" class="smpl">Content-Range</a> header field specifying the current length of the representation (see <a href="#header.content-range" id="rfc.xref.header.content-range.3" title="Content-Range">Section&nbsp;5.2</a>). This response <em class="bcp14">MUST NOT</em> use the multipart/byteranges content-type. For example,
742      </p>
743      <div id="rfc.figure.u.4"></div><pre class="text">HTTP/1.1 416 Requested Range Not Satisfiable
744Date: Mon, 20 Jan 2012 15:41:54 GMT
745Content-Range: bytes */47022
746Content-Type: image/gif
747</pre><div class="note" id="rfc.section.3.2.p.4"> 
748         <p> <b>Note:</b> Clients cannot depend on servers to send a <a href="#status.416" class="smpl">416 (Requested
749               Range Not Satisfiable)</a> response instead of a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response for an unsatisfiable <a href="#range.retrieval.requests" class="smpl">Range</a> header field, since not all servers implement this header field.
750         </p> 
751      </div>
752      <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;Responses to a Range Request
753      </h1>
754      <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;Response to a Single and Multiple Ranges Request
755      </h2>
756      <p id="rfc.section.4.1.p.1">When an HTTP message includes the content of a single range (for example, a response to a request for a single range, or to
757         a request for a set of ranges that overlap without any holes), this content is transmitted with a <a href="#header.content-range" class="smpl">Content-Range</a> header field, and a <a href="p1-messaging.html#header.content-length" class="smpl">Content-Length</a> header field showing the number of bytes actually transferred. For example,
758      </p>
759      <div id="rfc.figure.u.5"></div><pre class="text">HTTP/1.1 206 Partial Content
760Date: Wed, 15 Nov 1995 06:25:24 GMT
761Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
762Content-Range: bytes 21010-47021/47022
763Content-Length: 26012
764Content-Type: image/gif
765</pre><p id="rfc.section.4.1.p.3">When an HTTP message includes the content of multiple ranges (for example, a response to a request for multiple non-overlapping
766         ranges), these are transmitted as a multipart message. The multipart media type used for this purpose is "multipart/byteranges"
767         as defined in <a href="#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix&nbsp;A</a>.
768      </p>
769      <p id="rfc.section.4.1.p.4">A server <em class="bcp14">MAY</em> combine requested ranges when those ranges are overlapping (see <a href="#overlapping.ranges" title="Overlapping Ranges">Section&nbsp;7.1</a>).
770      </p>
771      <p id="rfc.section.4.1.p.5">A response to a request for a single range <em class="bcp14">MUST NOT</em> be sent using the multipart/byteranges media type. A response to a request for multiple ranges, whose result is a single range, <em class="bcp14">MAY</em> be sent as a multipart/byteranges media type with one part. A client that cannot decode a multipart/byteranges message <em class="bcp14">MUST NOT</em> ask for multiple ranges in a single request.
772      </p>
773      <p id="rfc.section.4.1.p.6">When a client asks for multiple ranges in one request, the server <em class="bcp14">SHOULD</em> return them in the order that they appeared in the request.
774      </p>
775      <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a>&nbsp;<a id="combining.byte.ranges" href="#combining.byte.ranges">Combining Ranges</a></h2>
776      <p id="rfc.section.4.2.p.1">A response might transfer only a subrange of a representation if the connection closed prematurely or if the request used
777         one or more Range specifications. After several such transfers, a client might have received several ranges of the same representation.
778         These ranges can only be safely combined if they all have in common the same strong validator, where "strong validator" is
779         defined to be either an entity-tag that is not marked as weak (<a href="p4-conditional.html#header.etag" title="ETag">Section 2.3</a> of <a href="#Part4" id="rfc.xref.Part4.2"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>) or, if no entity-tag is provided, a <a href="p4-conditional.html#header.last-modified" class="smpl">Last-Modified</a> value that is strong in the sense defined by <a href="p4-conditional.html#lastmod.comparison" title="Comparison">Section 2.2.2</a> of <a href="#Part4" id="rfc.xref.Part4.3"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>.
780      </p>
781      <p id="rfc.section.4.2.p.2">When a client receives an incomplete <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> or <a href="#status.206" class="smpl">206 (Partial Content)</a> response and already has one or more stored responses for the same method and effective request URI, all of the stored responses
782         with the same strong validator <em class="bcp14">MAY</em> be combined with the partial content in this new response. If none of the stored responses contain the same strong validator,
783         then this new response corresponds to a new representation and <em class="bcp14">MUST NOT</em> be combined with the existing stored responses.
784      </p>
785      <p id="rfc.section.4.2.p.3">If the new response is an incomplete <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response, then the header fields of that new response are used for any combined response and replace those of the matching
786         stored responses.
787      </p>
788      <p id="rfc.section.4.2.p.4">If the new response is a <a href="#status.206" class="smpl">206 (Partial Content)</a> response and at least one of the matching stored responses is a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a>, then the combined response header fields consist of the most recent 200 response's header fields. If all of the matching
789         stored responses are 206 responses, then the stored response with the most header fields is used as the source of header fields
790         for the combined response, except that the client <em class="bcp14">MUST</em> use other header fields provided in the new response, aside from <a href="#header.content-range" class="smpl">Content-Range</a>, to replace all instances of the corresponding header fields in the stored response.
791      </p>
792      <p id="rfc.section.4.2.p.5">The combined response message body consists of the union of partial content ranges in the new response and each of the selected
793         responses. If the union consists of the entire range of the representation, then the combined response <em class="bcp14">MUST</em> be recorded as a complete <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response with a <a href="p1-messaging.html#header.content-length" class="smpl">Content-Length</a> header field that reflects the complete length. Otherwise, the combined response(s) <em class="bcp14">MUST</em> include a <a href="#header.content-range" class="smpl">Content-Range</a> header field describing the included range(s) and be recorded as incomplete. If the union consists of a discontinuous range
794         of the representation, then the client <em class="bcp14">MAY</em> store it as either a multipart range response or as multiple <a href="#status.206" class="smpl">206</a> responses with one continuous range each.
795      </p>
796      <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1>
797      <p id="rfc.section.5.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to range requests and partial responses.</p>
798      <div id="rfc.iref.a.1"></div>
799      <div id="rfc.iref.h.1"></div>
800      <h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a>&nbsp;<a id="header.accept-ranges" href="#header.accept-ranges">Accept-Ranges</a></h2>
801      <p id="rfc.section.5.1.p.1">The "Accept-Ranges" header field allows a resource to indicate its acceptance of range requests.</p>
802      <div id="rfc.figure.u.6"></div><pre class="inline"><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span>  <a href="#header.accept-ranges" class="smpl">Accept-Ranges</a>     = <a href="#header.accept-ranges" class="smpl">acceptable-ranges</a>
803  <a href="#header.accept-ranges" class="smpl">acceptable-ranges</a> = 1#<a href="#range.units" class="smpl">range-unit</a> / "none"
804</pre><p id="rfc.section.5.1.p.3">Origin servers that accept byte-range requests <em class="bcp14">MAY</em> send
805      </p>
806      <div id="rfc.figure.u.7"></div><pre class="text">  Accept-Ranges: bytes
807</pre><p id="rfc.section.5.1.p.5">but are not required to do so. Clients <em class="bcp14">MAY</em> generate range requests without having received this header field for the resource involved. Range units are defined in <a href="#range.units" title="Range Units">Section&nbsp;2</a>.
808      </p>
809      <p id="rfc.section.5.1.p.6">Servers that do not accept any kind of range request for a resource <em class="bcp14">MAY</em> send
810      </p>
811      <div id="rfc.figure.u.8"></div><pre class="text">  Accept-Ranges: none
812</pre><p id="rfc.section.5.1.p.8">to advise the client not to attempt a range request.</p>
813      <div id="rfc.iref.c.1"></div>
814      <div id="rfc.iref.h.2"></div>
815      <h2 id="rfc.section.5.2"><a href="#rfc.section.5.2">5.2</a>&nbsp;<a id="header.content-range" href="#header.content-range">Content-Range</a></h2>
816      <p id="rfc.section.5.2.p.1">The "Content-Range" header field is sent with a partial representation to specify where in the full representation the payload
817         body is intended to be applied.
818      </p>
819      <p id="rfc.section.5.2.p.2">Range units are defined in <a href="#range.units" title="Range Units">Section&nbsp;2</a>.
820      </p>
821      <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.6"></span><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span>  <a href="#header.content-range" class="smpl">Content-Range</a>           = <a href="#header.content-range" class="smpl">byte-content-range-spec</a>
822                          / <a href="#header.content-range" class="smpl">other-content-range-spec</a>
823                         
824  <a href="#header.content-range" class="smpl">byte-content-range-spec</a> = <a href="#range.units" class="smpl">bytes-unit</a> <a href="#notation" class="smpl">SP</a>
825                            <a href="#header.content-range" class="smpl">byte-range-resp-spec</a> "/"
826                            ( <a href="#header.content-range" class="smpl">instance-length</a> / "*" )
827 
828  <a href="#header.content-range" class="smpl">byte-range-resp-spec</a>    = (<a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a> "-" <a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a>)
829                          / "*"
830                         
831  <a href="#header.content-range" class="smpl">instance-length</a>         = 1*<a href="#notation" class="smpl">DIGIT</a>
832 
833  <a href="#header.content-range" class="smpl">other-content-range-spec</a> = <a href="#range.units" class="smpl">other-range-unit</a> <a href="#notation" class="smpl">SP</a>
834                             <a href="#header.content-range" class="smpl">other-range-resp-spec</a>
835  <a href="#header.content-range" class="smpl">other-range-resp-spec</a>    = *<a href="#notation" class="smpl">CHAR</a>
836</pre><p id="rfc.section.5.2.p.4">The header field <em class="bcp14">SHOULD</em> indicate the total length of the full representation, unless this length is unknown or difficult to determine. The asterisk
837         "*" character means that the instance-length is unknown at the time when the response was generated.
838      </p>
839      <p id="rfc.section.5.2.p.5">Unlike byte-ranges-specifier values (see <a href="#byte.ranges" title="Byte Ranges">Section&nbsp;5.4.1</a>), a byte-range-resp-spec <em class="bcp14">MUST</em> only specify one range, and <em class="bcp14">MUST</em> contain absolute byte positions for both the first and last byte of the range.
840      </p>
841      <p id="rfc.section.5.2.p.6">A byte-content-range-spec with a byte-range-resp-spec whose last-byte-pos value is less than its first-byte-pos value, or
842         whose instance-length value is less than or equal to its last-byte-pos value, is invalid. The recipient of an invalid byte-content-range-spec <em class="bcp14">MUST</em> ignore it and any content transferred along with it.
843      </p>
844      <p id="rfc.section.5.2.p.7">In the case of a byte range request: A server sending a response with status code <a href="#status.416" class="smpl">416 (Requested Range Not
845            Satisfiable)</a>  <em class="bcp14">SHOULD</em> include a Content-Range field with a byte-range-resp-spec of "*". The instance-length specifies the current length of the
846         selected resource. A response with status code <a href="#status.206" class="smpl">206 (Partial Content)</a>  <em class="bcp14">MUST NOT</em> include a Content-Range field with a byte-range-resp-spec of "*".
847      </p>
848      <p id="rfc.section.5.2.p.8">The "Content-Range" header field has no meaning for status codes that do not explicitly describe its semantic. Currently,
849         only status codes <a href="#status.206" class="smpl">206 (Partial Content)</a> and <a href="#status.416" class="smpl">416 (Requested Range Not Satisfiable)</a> describe the meaning of this header field.
850      </p>
851      <p id="rfc.section.5.2.p.9">Examples of byte-content-range-spec values, assuming that the representation contains a total of 1234 bytes: </p>
852      <ul>
853         <li>The first 500 bytes:
854            <div id="rfc.figure.u.10"></div><pre class="text">  bytes 0-499/1234
855</pre> </li>
856         <li>The second 500 bytes:
857            <div id="rfc.figure.u.11"></div><pre class="text">  bytes 500-999/1234
858</pre> </li>
859         <li>All except for the first 500 bytes:
860            <div id="rfc.figure.u.12"></div><pre class="text">  bytes 500-1233/1234
861</pre> </li>
862         <li>The last 500 bytes:
863            <div id="rfc.figure.u.13"></div><pre class="text">  bytes 734-1233/1234
864</pre> </li>
865      </ul>
866      <p id="rfc.section.5.2.p.10">If the server ignores a byte-range-spec (for example if it is syntactically invalid, or if it might be seen as a denial-of-service
867         attack), the server <em class="bcp14">SHOULD</em> treat the request as if the invalid <a href="#range.retrieval.requests" class="smpl">Range</a> header field did not exist. (Normally, this means return a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response containing the full representation).
868      </p>
869      <div id="rfc.iref.i.1"></div>
870      <div id="rfc.iref.h.3"></div>
871      <h2 id="rfc.section.5.3"><a href="#rfc.section.5.3">5.3</a>&nbsp;<a id="header.if-range" href="#header.if-range">If-Range</a></h2>
872      <p id="rfc.section.5.3.p.1">If a client has a partial copy of a representation and wishes to have an up-to-date copy of the entire representation, it
873         could use the <a href="#range.retrieval.requests" class="smpl">Range</a> header field with a conditional GET (using either or both of <a href="p4-conditional.html#header.if-unmodified-since" class="smpl">If-Unmodified-Since</a> and <a href="p4-conditional.html#header.if-match" class="smpl">If-Match</a>.) However, if the condition fails because the representation has been modified, the client would then have to make a second
874         request to obtain the entire current representation.
875      </p>
876      <p id="rfc.section.5.3.p.2">The "If-Range" header field allows a client to "short-circuit" the second request. Informally, its meaning is "if the representation
877         is unchanged, send me the part(s) that I am missing; otherwise, send me the entire new representation".
878      </p>
879      <div id="rfc.figure.u.14"></div><pre class="inline"><span id="rfc.iref.g.10"></span>  <a href="#header.if-range" class="smpl">If-Range</a> = <a href="#abnf.dependencies" class="smpl">entity-tag</a> / <a href="#core.rules" class="smpl">HTTP-date</a>
880</pre><p id="rfc.section.5.3.p.4">Clients <em class="bcp14">MUST NOT</em> use an entity-tag marked as weak in an If-Range field value and <em class="bcp14">MUST NOT</em> use a <a href="p4-conditional.html#header.last-modified" class="smpl">Last-Modified</a> date in an If-Range field value unless it has no entity-tag for the representation and the Last-Modified date it does have
881         for the representation is strong in the sense defined by <a href="p4-conditional.html#lastmod.comparison" title="Comparison">Section 2.2.2</a> of <a href="#Part4" id="rfc.xref.Part4.4"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>.
882      </p>
883      <p id="rfc.section.5.3.p.5">A server that evaluates a conditional range request that is applicable to one of its representations <em class="bcp14">MUST</em> evaluate the condition as false if the entity-tag used as a validator is marked as weak or, when an HTTP-date is used as the
884         validator, if the date value is not strong in the sense defined by <a href="p4-conditional.html#lastmod.comparison" title="Comparison">Section 2.2.2</a> of <a href="#Part4" id="rfc.xref.Part4.5"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>. (A server can distinguish between a valid HTTP-date and any form of entity-tag by examining the first two characters.)
885      </p>
886      <p id="rfc.section.5.3.p.6">The If-Range header field <em class="bcp14">SHOULD</em> only be sent by clients together with a Range header field. The If-Range header field <em class="bcp14">MUST</em> be ignored if it is received in a request that does not include a Range header field. The If-Range header field <em class="bcp14">MUST</em> be ignored by a server that does not support the sub-range operation.
887      </p>
888      <p id="rfc.section.5.3.p.7">If the validator given in the If-Range header field matches the current validator for the selected representation of the target
889         resource, then the server <em class="bcp14">SHOULD</em> send the specified sub-range of the representation using a <a href="#status.206" class="smpl">206 (Partial Content)</a> response. If the validator does not match, then the server <em class="bcp14">SHOULD</em> send the entire representation using a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response.
890      </p>
891      <div id="rfc.iref.r.1"></div>
892      <div id="rfc.iref.h.4"></div>
893      <h2 id="rfc.section.5.4"><a href="#rfc.section.5.4">5.4</a>&nbsp;<a id="header.range" href="#header.range">Range</a></h2>
894      <h3 id="rfc.section.5.4.1"><a href="#rfc.section.5.4.1">5.4.1</a>&nbsp;<a id="byte.ranges" href="#byte.ranges">Byte Ranges</a></h3>
895      <p id="rfc.section.5.4.1.p.1">Since all HTTP representations are transferred as sequences of bytes, the concept of a byte range is meaningful for any HTTP
896         representation. (However, not all clients and servers need to support byte-range operations.)
897      </p>
898      <p id="rfc.section.5.4.1.p.2">Byte range specifications in HTTP apply to the sequence of bytes in the representation body (not necessarily the same as the
899         message body).
900      </p>
901      <div id="rule.ranges-specifier">
902         <p id="rfc.section.5.4.1.p.3">                A byte range operation <em class="bcp14">MAY</em> specify a single range of bytes, or a set of ranges within a single representation.
903         </p>
904      </div>
905      <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span><span id="rfc.iref.g.15"></span><span id="rfc.iref.g.16"></span>  <a href="#rule.ranges-specifier" class="smpl">byte-ranges-specifier</a> = <a href="#range.units" class="smpl">bytes-unit</a> "=" <a href="#rule.ranges-specifier" class="smpl">byte-range-set</a>
906  <a href="#rule.ranges-specifier" class="smpl">byte-range-set</a>  = 1#( <a href="#rule.ranges-specifier" class="smpl">byte-range-spec</a> / <a href="#rule.ranges-specifier" class="smpl">suffix-byte-range-spec</a> )
907  <a href="#rule.ranges-specifier" class="smpl">byte-range-spec</a> = <a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a> "-" [ <a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a> ]
908  <a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a>  = 1*<a href="#notation" class="smpl">DIGIT</a>
909  <a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a>   = 1*<a href="#notation" class="smpl">DIGIT</a>
910</pre><p id="rfc.section.5.4.1.p.5">The first-byte-pos value in a byte-range-spec gives the byte-offset of the first byte in a range. The last-byte-pos value
911         gives the byte-offset of the last byte in the range; that is, the byte positions specified are inclusive. Byte offsets start
912         at zero.
913      </p>
914      <p id="rfc.section.5.4.1.p.6">If the last-byte-pos value is present, it <em class="bcp14">MUST</em> be greater than or equal to the first-byte-pos in that byte-range-spec, or the byte-range-spec is syntactically invalid. The
915         recipient of a byte-range-set that includes one or more syntactically invalid byte-range-spec values <em class="bcp14">MUST</em> ignore the header field that includes that byte-range-set.
916      </p>
917      <p id="rfc.section.5.4.1.p.7">If the last-byte-pos value is absent, or if the value is greater than or equal to the current length of the representation
918         body, last-byte-pos is taken to be equal to one less than the current length of the representation in bytes.
919      </p>
920      <p id="rfc.section.5.4.1.p.8">By its choice of last-byte-pos, a client can limit the number of bytes retrieved without knowing the size of the representation.</p>
921      <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.17"></span><span id="rfc.iref.g.18"></span>  <a href="#rule.ranges-specifier" class="smpl">suffix-byte-range-spec</a> = "-" <a href="#rule.ranges-specifier" class="smpl">suffix-length</a>
922  <a href="#rule.ranges-specifier" class="smpl">suffix-length</a> = 1*<a href="#notation" class="smpl">DIGIT</a>
923</pre><p id="rfc.section.5.4.1.p.10">A suffix-byte-range-spec is used to specify the suffix of the representation body, of a length given by the suffix-length
924         value. (That is, this form specifies the last N bytes of a representation.) If the representation is shorter than the specified
925         suffix-length, the entire representation is used.
926      </p>
927      <p id="rfc.section.5.4.1.p.11">If a syntactically valid byte-range-set includes at least one byte-range-spec whose first-byte-pos is less than the current
928         length of the representation, or at least one suffix-byte-range-spec with a non-zero suffix-length, then the byte-range-set
929         is satisfiable. Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set is unsatisfiable, the server <em class="bcp14">SHOULD</em> return a response with a <a href="#status.416" class="smpl">416 (Requested Range Not Satisfiable)</a> status code. Otherwise, the server <em class="bcp14">SHOULD</em> return a response with a <a href="#status.206" class="smpl">206 (Partial Content)</a> status code containing the satisfiable ranges of the representation.
930      </p>
931      <p id="rfc.section.5.4.1.p.12">In the byte range syntax, <a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a>, <a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a>, and <a href="#rule.ranges-specifier" class="smpl">suffix-length</a> are expressed as decimal number of octets. Since there is no predefined limit to the length of an HTTP payload, recipients <em class="bcp14">SHOULD</em> anticipate potentially large decimal numerals and prevent parsing errors due to integer conversion overflows.
932      </p>
933      <p id="rfc.section.5.4.1.p.13">Examples of byte-ranges-specifier values (assuming a representation of length 10000): </p>
934      <ul>
935         <li>The first 500 bytes (byte offsets 0-499, inclusive):
936            <div id="rfc.figure.u.17"></div><pre class="text">  bytes=0-499
937</pre> </li>
938         <li>The second 500 bytes (byte offsets 500-999, inclusive):
939            <div id="rfc.figure.u.18"></div><pre class="text">  bytes=500-999
940</pre> </li>
941         <li>The final 500 bytes (byte offsets 9500-9999, inclusive):
942            <div id="rfc.figure.u.19"></div><pre class="text">  bytes=-500
943</pre> Or: <div id="rfc.figure.u.20"></div><pre class="text">  bytes=9500-
944</pre> </li>
945         <li>The first and last bytes only (bytes 0 and 9999):
946            <div id="rfc.figure.u.21"></div><pre class="text">  bytes=0-0,-1
947</pre> </li>
948         <li>Several legal but not canonical specifications of the second 500 bytes (byte offsets 500-999, inclusive):
949            <div id="rfc.figure.u.22"></div><pre class="text">  bytes=500-600,601-999
950  bytes=500-700,601-999
951</pre> </li>
952      </ul>
953      <h3 id="rfc.section.5.4.2"><a href="#rfc.section.5.4.2">5.4.2</a>&nbsp;<a id="range.retrieval.requests" href="#range.retrieval.requests">Range Retrieval Requests</a></h3>
954      <p id="rfc.section.5.4.2.p.1">The "Range" header field defines the GET method (conditional or not) to request one or more sub-ranges of the response representation
955         body, instead of the entire representation body.
956      </p>
957      <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.19"></span>  <a href="#range.retrieval.requests" class="smpl">Range</a> = <a href="#rule.ranges-specifier" class="smpl">byte-ranges-specifier</a> / <a href="#range.retrieval.requests" class="smpl">other-ranges-specifier</a>
958  <a href="#range.retrieval.requests" class="smpl">other-ranges-specifier</a> = <a href="#range.units" class="smpl">other-range-unit</a> "=" <a href="#range.retrieval.requests" class="smpl">other-range-set</a>
959  <a href="#range.retrieval.requests" class="smpl">other-range-set</a> = 1*<a href="#notation" class="smpl">CHAR</a>
960</pre><p id="rfc.section.5.4.2.p.3">A server <em class="bcp14">MAY</em> ignore the Range header field. However, origin servers and intermediate caches ought to support byte ranges when possible,
961         since Range supports efficient recovery from partially failed transfers, and supports efficient partial retrieval of large
962         representations.
963      </p>
964      <p id="rfc.section.5.4.2.p.4">If the server supports the Range header field and the specified range or ranges are appropriate for the representation: </p>
965      <ul>
966         <li>The presence of a Range header field in an unconditional GET modifies what is returned if the GET is otherwise successful.
967            In other words, the response carries a status code of <a href="#status.206" class="smpl">206 (Partial Content)</a> instead of <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a>.
968         </li>
969         <li>The presence of a Range header field in a conditional GET (a request using one or both of <a href="p4-conditional.html#header.if-modified-since" class="smpl">If-Modified-Since</a> and <a href="p4-conditional.html#header.if-none-match" class="smpl">If-None-Match</a>, or one or both of <a href="p4-conditional.html#header.if-unmodified-since" class="smpl">If-Unmodified-Since</a> and <a href="p4-conditional.html#header.if-match" class="smpl">If-Match</a>) modifies what is returned if the GET is otherwise successful and the condition is true. It does not affect the <a href="p4-conditional.html#status.304" class="smpl">304 (Not Modified)</a> response returned if the conditional is false.
970         </li>
971      </ul>
972      <p id="rfc.section.5.4.2.p.5">In some cases, it might be more appropriate to use the If-Range header field (see <a href="#header.if-range" id="rfc.xref.header.if-range.3" title="If-Range">Section&nbsp;5.3</a>) in addition to the Range header field.
973      </p>
974      <p id="rfc.section.5.4.2.p.6">If a proxy that supports ranges receives a Range request, forwards the request to an inbound server, and receives an entire
975         representation in reply, it <em class="bcp14">MAY</em> only return the requested range to its client.
976      </p>
977      <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
978      <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a id="status.code.registration" href="#status.code.registration">Status Code Registration</a></h2>
979      <p id="rfc.section.6.1.p.1">The HTTP Status Code Registry located at &lt;<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>&gt; shall be updated with the registrations below:
980      </p>
981      <div id="rfc.table.1">
982         <div id="iana.status.code.registration.table"></div>
983         <table class="tt full left" cellpadding="3" cellspacing="0">
984            <thead>
985               <tr>
986                  <th>Value</th>
987                  <th>Description</th>
988                  <th>Reference</th>
989               </tr>
990            </thead>
991            <tbody>
992               <tr>
993                  <td class="left">206</td>
994                  <td class="left">Partial Content</td>
995                  <td class="left"> <a href="#status.206" id="rfc.xref.status.206.1" title="206 Partial Content">Section&nbsp;3.1</a> 
996                  </td>
997               </tr>
998               <tr>
999                  <td class="left">416</td>
1000                  <td class="left">Requested Range Not Satisfiable</td>
1001                  <td class="left"> <a href="#status.416" id="rfc.xref.status.416.1" title="416 Requested Range Not Satisfiable">Section&nbsp;3.2</a> 
1002                  </td>
1003               </tr>
1004            </tbody>
1005         </table>
1006      </div>
1007      <h2 id="rfc.section.6.2"><a href="#rfc.section.6.2">6.2</a>&nbsp;<a id="header.field.registration" href="#header.field.registration">Header Field Registration</a></h2>
1008      <p id="rfc.section.6.2.p.1">The Message Header Field Registry located at &lt;<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>&gt; shall 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>):
1009      </p>
1010      <div id="rfc.table.2">
1011         <div id="iana.header.registration.table"></div>
1012         <table class="tt full left" cellpadding="3" cellspacing="0">
1013            <thead>
1014               <tr>
1015                  <th>Header Field Name</th>
1016                  <th>Protocol</th>
1017                  <th>Status</th>
1018                  <th>Reference</th>
1019               </tr>
1020            </thead>
1021            <tbody>
1022               <tr>
1023                  <td class="left">Accept-Ranges</td>
1024                  <td class="left">http</td>
1025                  <td class="left">standard</td>
1026                  <td class="left"> <a href="#header.accept-ranges" id="rfc.xref.header.accept-ranges.1" title="Accept-Ranges">Section&nbsp;5.1</a> 
1027                  </td>
1028               </tr>
1029               <tr>
1030                  <td class="left">Content-Range</td>
1031                  <td class="left">http</td>
1032                  <td class="left">standard</td>
1033                  <td class="left"> <a href="#header.content-range" id="rfc.xref.header.content-range.4" title="Content-Range">Section&nbsp;5.2</a> 
1034                  </td>
1035               </tr>
1036               <tr>
1037                  <td class="left">If-Range</td>
1038                  <td class="left">http</td>
1039                  <td class="left">standard</td>
1040                  <td class="left"> <a href="#header.if-range" id="rfc.xref.header.if-range.4" title="If-Range">Section&nbsp;5.3</a> 
1041                  </td>
1042               </tr>
1043               <tr>
1044                  <td class="left">Range</td>
1045                  <td class="left">http</td>
1046                  <td class="left">standard</td>
1047                  <td class="left"> <a href="#header.range" id="rfc.xref.header.range.5" title="Range">Section&nbsp;5.4</a> 
1048                  </td>
1049               </tr>
1050            </tbody>
1051         </table>
1052      </div>
1053      <p id="rfc.section.6.2.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
1054      <h2 id="rfc.section.6.3"><a href="#rfc.section.6.3">6.3</a>&nbsp;<a id="range.specifier.registration" href="#range.specifier.registration">Range Specifier Registration</a></h2>
1055      <p id="rfc.section.6.3.p.1">The registration procedure for HTTP Range Specifiers is defined by <a href="#range.specifier.registry" title="Range Specifier Registry">Section&nbsp;2.1</a> of this document.
1056      </p>
1057      <p id="rfc.section.6.3.p.2">The HTTP Range Specifier Registry shall be created at &lt;<a href="http://www.iana.org/assignments/http-range-specifiers">http://www.iana.org/assignments/http-range-specifiers</a>&gt; and be populated with the registrations below:
1058      </p>
1059      <div id="rfc.table.3">
1060         <div id="iana.range.specifiers.table"></div>
1061         <table class="tt full left" cellpadding="3" cellspacing="0">
1062            <thead>
1063               <tr>
1064                  <th>Range Specifier Name</th>
1065                  <th>Description</th>
1066                  <th>Reference</th>
1067               </tr>
1068            </thead>
1069            <tbody>
1070               <tr>
1071                  <td class="left">bytes</td>
1072                  <td class="left">a range of octets</td>
1073                  <td class="left"><a href="#range.units" title="Range Units">Section&nbsp;2</a></td>
1074               </tr>
1075               <tr>
1076                  <td class="left">none</td>
1077                  <td class="left">reserved as keyword, indicating no ranges are supported</td>
1078                  <td class="left"><a href="#header.accept-ranges" id="rfc.xref.header.accept-ranges.2" title="Accept-Ranges">Section&nbsp;5.1</a></td>
1079               </tr>
1080            </tbody>
1081         </table>
1082      </div>
1083      <p id="rfc.section.6.3.p.3">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
1084      <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="security.considerations" href="#security.considerations">Security Considerations</a></h1>
1085      <p id="rfc.section.7.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
1086         as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does
1087         make some suggestions for reducing security risks.
1088      </p>
1089      <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a id="overlapping.ranges" href="#overlapping.ranges">Overlapping Ranges</a></h2>
1090      <p id="rfc.section.7.1.p.1">Range requests containing overlapping ranges can lead to the situation where a server is sending far more data than the size
1091         of the complete resource representation.
1092      </p>
1093      <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a id="acks" href="#acks">Acknowledgments</a></h1>
1094      <p id="rfc.section.8.p.1">See <a href="p1-messaging.html#acks" title="Acknowledgments">Section 9</a> of <a href="#Part1" id="rfc.xref.Part1.6"><cite title="HTTP/1.1, part 1: Message Routing and Syntax&#34;">[Part1]</cite></a>.
1095      </p>
1096      <h1 id="rfc.references"><a id="rfc.section.9" href="#rfc.section.9">9.</a> References
1097      </h1>
1098      <h2 id="rfc.references.1"><a href="#rfc.section.9.1" id="rfc.section.9.1">9.1</a> Normative References
1099      </h2>
1100      <table>             
1101         <tr>
1102            <td class="reference"><b id="Part1">[Part1]</b></td>
1103            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-latest">HTTP/1.1, part 1: Message Routing and Syntax"</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p1-messaging-latest (work in progress), July&nbsp;2012.
1104            </td>
1105         </tr>
1106         <tr>
1107            <td class="reference"><b id="Part2">[Part2]</b></td>
1108            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-latest">HTTP/1.1, part 2: Semantics and Payloads</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p2-semantics-latest (work in progress), July&nbsp;2012.
1109            </td>
1110         </tr>
1111         <tr>
1112            <td class="reference"><b id="Part4">[Part4]</b></td>
1113            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p4-conditional-latest">HTTP/1.1, part 4: Conditional Requests</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p4-conditional-latest (work in progress), July&nbsp;2012.
1114            </td>
1115         </tr>
1116         <tr>
1117            <td class="reference"><b id="Part6">[Part6]</b></td>
1118            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, <a href="mailto:mnot@mnot.net" title="Rackspace">Nottingham, M., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p6-cache-latest">HTTP/1.1, part 6: Caching</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p6-cache-latest (work in progress), July&nbsp;2012.
1119            </td>
1120         </tr>
1121         <tr>
1122            <td class="reference"><b id="RFC2046">[RFC2046]</b></td>
1123            <td class="top"><a href="mailto:ned@innosoft.com" title="Innosoft International, Inc.">Freed, N.</a> and <a href="mailto:nsb@nsb.fv.com" title="First Virtual Holdings">N. Borenstein</a>, “<a href="http://tools.ietf.org/html/rfc2046">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</a>”, RFC&nbsp;2046, November&nbsp;1996.
1124            </td>
1125         </tr>
1126         <tr>
1127            <td class="reference"><b id="RFC2119">[RFC2119]</b></td>
1128            <td class="top"><a href="mailto:sob@harvard.edu" title="Harvard University">Bradner, S.</a>, “<a href="http://tools.ietf.org/html/rfc2119">Key words for use in RFCs to Indicate Requirement Levels</a>”, BCP&nbsp;14, RFC&nbsp;2119, March&nbsp;1997.
1129            </td>
1130         </tr>
1131         <tr>
1132            <td class="reference"><b id="RFC5234">[RFC5234]</b></td>
1133            <td class="top"><a href="mailto:dcrocker@bbiw.net" title="Brandenburg InternetWorking">Crocker, D., Ed.</a> and <a href="mailto:paul.overell@thus.net" title="THUS plc.">P. Overell</a>, “<a href="http://tools.ietf.org/html/rfc5234">Augmented BNF for Syntax Specifications: ABNF</a>”, STD&nbsp;68, RFC&nbsp;5234, January&nbsp;2008.
1134            </td>
1135         </tr>
1136      </table>
1137      <h2 id="rfc.references.2"><a href="#rfc.section.9.2" id="rfc.section.9.2">9.2</a> Informative References
1138      </h2>
1139      <table>       
1140         <tr>
1141            <td class="reference"><b id="RFC2616">[RFC2616]</b></td>
1142            <td class="top"><a href="mailto:fielding@ics.uci.edu" title="University of California, Irvine">Fielding, R.</a>, <a href="mailto:jg@w3.org" title="W3C">Gettys, J.</a>, <a href="mailto:mogul@wrl.dec.com" title="Compaq Computer Corporation">Mogul, J.</a>, <a href="mailto:frystyk@w3.org" title="MIT Laboratory for Computer Science">Frystyk, H.</a>, <a href="mailto:masinter@parc.xerox.com" title="Xerox Corporation">Masinter, L.</a>, <a href="mailto:paulle@microsoft.com" title="Microsoft Corporation">Leach, P.</a>, and <a href="mailto:timbl@w3.org" title="W3C">T. Berners-Lee</a>, “<a href="http://tools.ietf.org/html/rfc2616">Hypertext Transfer Protocol -- HTTP/1.1</a>”, RFC&nbsp;2616, June&nbsp;1999.
1143            </td>
1144         </tr>
1145         <tr>
1146            <td class="reference"><b id="RFC3864">[RFC3864]</b></td>
1147            <td class="top"><a href="mailto:GK-IETF@ninebynine.org" title="Nine by Nine">Klyne, G.</a>, <a href="mailto:mnot@pobox.com" title="BEA Systems">Nottingham, M.</a>, and <a href="mailto:JeffMogul@acm.org" title="HP Labs">J. Mogul</a>, “<a href="http://tools.ietf.org/html/rfc3864">Registration Procedures for Message Header Fields</a>”, BCP&nbsp;90, RFC&nbsp;3864, September&nbsp;2004.
1148            </td>
1149         </tr>
1150         <tr>
1151            <td class="reference"><b id="RFC4288">[RFC4288]</b></td>
1152            <td class="top"><a href="mailto:ned.freed@mrochek.com" title="Sun Microsystems">Freed, N.</a> and <a href="mailto:klensin+ietf@jck.com">J. Klensin</a>, “<a href="http://tools.ietf.org/html/rfc4288">Media Type Specifications and Registration Procedures</a>”, BCP&nbsp;13, RFC&nbsp;4288, December&nbsp;2005.
1153            </td>
1154         </tr>
1155         <tr>
1156            <td class="reference"><b id="RFC5226">[RFC5226]</b></td>
1157            <td class="top"><a href="mailto:narten@us.ibm.com" title="IBM">Narten, T.</a> and <a href="mailto:Harald@Alvestrand.no" title="Google">H. Alvestrand</a>, “<a href="http://tools.ietf.org/html/rfc5226">Guidelines for Writing an IANA Considerations Section in RFCs</a>”, BCP&nbsp;26, RFC&nbsp;5226, May&nbsp;2008.
1158            </td>
1159         </tr>
1160      </table>
1161      <div class="avoidbreak">
1162         <h1 id="rfc.authors"><a href="#rfc.authors">Authors' Addresses</a></h1>
1163         <address class="vcard"><span class="vcardline"><span class="fn">Roy T. Fielding</span>
1164               (editor)
1165               <span class="n hidden"><span class="family-name">Fielding</span><span class="given-name">Roy T.</span></span></span><span class="org vcardline">Adobe Systems Incorporated</span><span class="adr"><span class="street-address vcardline">345 Park Ave</span><span class="vcardline"><span class="locality">San Jose</span>, <span class="region">CA</span>&nbsp;<span class="postal-code">95110</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:fielding@gbiv.com"><span class="email">fielding@gbiv.com</span></a></span><span class="vcardline">URI: <a href="http://roy.gbiv.com/" class="url">http://roy.gbiv.com/</a></span></address>
1166         <address class="vcard"><span class="vcardline"><span class="fn">Yves Lafon</span>
1167               (editor)
1168               <span class="n hidden"><span class="family-name">Lafon</span><span class="given-name">Yves</span></span></span><span class="org vcardline">World Wide Web Consortium</span><span class="adr"><span class="street-address vcardline">W3C / ERCIM</span><span class="street-address vcardline">2004, rte des Lucioles</span><span class="vcardline"><span class="locality">Sophia-Antipolis</span>, <span class="region">AM</span>&nbsp;<span class="postal-code">06902</span></span><span class="country-name vcardline">France</span></span><span class="vcardline">Email: <a href="mailto:ylafon@w3.org"><span class="email">ylafon@w3.org</span></a></span><span class="vcardline">URI: <a href="http://www.raubacapeu.net/people/yves/" class="url">http://www.raubacapeu.net/people/yves/</a></span></address>
1169         <address class="vcard"><span class="vcardline"><span class="fn">Julian F. Reschke</span>
1170               (editor)
1171               <span class="n hidden"><span class="family-name">Reschke</span><span class="given-name">Julian F.</span></span></span><span class="org vcardline">greenbytes GmbH</span><span class="adr"><span class="street-address vcardline">Hafenweg 16</span><span class="vcardline"><span class="locality">Muenster</span>, <span class="region">NW</span>&nbsp;<span class="postal-code">48155</span></span><span class="country-name vcardline">Germany</span></span><span class="vcardline">Email: <a href="mailto:julian.reschke@greenbytes.de"><span class="email">julian.reschke@greenbytes.de</span></a></span><span class="vcardline">URI: <a href="http://greenbytes.de/tech/webdav/" class="url">http://greenbytes.de/tech/webdav/</a></span></address>
1172      </div>
1173      <div id="rfc.iref.m.1"></div>
1174      <div id="rfc.iref.m.2"></div>
1175      <h1 id="rfc.section.A" class="np"><a href="#rfc.section.A">A.</a>&nbsp;<a id="internet.media.type.multipart.byteranges" href="#internet.media.type.multipart.byteranges">Internet Media Type multipart/byteranges</a></h1>
1176      <p id="rfc.section.A.p.1">When an HTTP <a href="#status.206" class="smpl">206 (Partial Content)</a> response message includes the content of multiple ranges (a response to a request for multiple non-overlapping ranges), these
1177         are transmitted as a multipart message body (<a href="#RFC2046" id="rfc.xref.RFC2046.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a>, <a href="http://tools.ietf.org/html/rfc2046#section-5.1">Section 5.1</a>). The media type for this purpose is called "multipart/byteranges". The following is to be registered with IANA <a href="#RFC4288" id="rfc.xref.RFC4288.1"><cite title="Media Type Specifications and Registration Procedures">[RFC4288]</cite></a>.
1178      </p>
1179      <p id="rfc.section.A.p.2">The multipart/byteranges media type includes one or more parts, each with its own <a href="p2-semantics.html#header.content-type" class="smpl">Content-Type</a> and <a href="#header.content-range" class="smpl">Content-Range</a> fields. The required boundary parameter specifies the boundary string used to separate each body-part.
1180      </p>
1181      <p id="rfc.section.A.p.3"> </p>
1182      <dl>
1183         <dt>Type name:</dt>
1184         <dd>multipart</dd>
1185         <dt>Subtype name:</dt>
1186         <dd>byteranges</dd>
1187         <dt>Required parameters:</dt>
1188         <dd>boundary</dd>
1189         <dt>Optional parameters:</dt>
1190         <dd>none</dd>
1191         <dt>Encoding considerations:</dt>
1192         <dd>only "7bit", "8bit", or "binary" are permitted</dd>
1193         <dt>Security considerations:</dt>
1194         <dd>none</dd>
1195         <dt>Interoperability considerations:</dt>
1196         <dd>none</dd>
1197         <dt>Published specification:</dt>
1198         <dd>This specification (see <a href="#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix&nbsp;A</a>).
1199         </dd>
1200         <dt>Applications that use this media type:</dt>
1201         <dd>HTTP components supporting multiple ranges in a single request.</dd>
1202         <dt>Additional information:</dt>
1203         <dd> 
1204            <dl>
1205               <dt>Magic number(s):</dt>
1206               <dd>none</dd>
1207               <dt>File extension(s):</dt>
1208               <dd>none</dd>
1209               <dt>Macintosh file type code(s):</dt>
1210               <dd>none</dd>
1211            </dl> 
1212         </dd>
1213         <dt>Person and email address to contact for further information:</dt>
1214         <dd>See Authors Section.</dd>
1215         <dt>Intended usage:</dt>
1216         <dd>COMMON</dd>
1217         <dt>Restrictions on usage:</dt>
1218         <dd>none</dd>
1219         <dt>Author/Change controller:</dt>
1220         <dd>IESG</dd>
1221      </dl>
1222      <div class="note" id="rfc.section.A.p.4"> 
1223         <p> <b>Note:</b> Despite the name "multipart/byteranges" is not limited to the byte ranges only.
1224         </p> 
1225      </div>
1226      <div id="rfc.figure.u.24"></div>
1227      <p>For example:</p><pre class="text">  HTTP/1.1 206 Partial Content
1228  Date: Wed, 15 Nov 1995 06:25:24 GMT
1229  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1230  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1231 
1232  --THIS_STRING_SEPARATES
1233  Content-type: application/pdf
1234  Content-range: bytes 500-999/8000
1235 
1236  ...the first range...
1237  --THIS_STRING_SEPARATES
1238  Content-type: application/pdf
1239  Content-range: bytes 7000-7999/8000
1240 
1241  ...the second range
1242  --THIS_STRING_SEPARATES--
1243</pre><div id="rfc.figure.u.25"></div>
1244      <p>Another example, using the "exampleunit" range unit:</p>  <pre class="text">  HTTP/1.1 206 Partial Content
1245  Date: Tue, 14 Nov 1995 06:25:24 GMT
1246  Last-Modified: Tue, 14 July 04:58:08 GMT
1247  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1248 
1249  --THIS_STRING_SEPARATES
1250  Content-type: video/example
1251  Content-range: exampleunit 1.2-4.3/25
1252 
1253  ...the first range...
1254  --THIS_STRING_SEPARATES
1255  Content-type: video/example
1256  Content-range: exampleunit 11.2-14.3/25
1257 
1258  ...the second range
1259  --THIS_STRING_SEPARATES--
1260</pre> <p id="rfc.section.A.p.7">Notes: </p>
1261      <ol>
1262         <li>Additional CRLFs <em class="bcp14">MAY</em> precede the first boundary string in the body.
1263         </li>
1264         <li>Although <a href="#RFC2046" id="rfc.xref.RFC2046.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> permits the boundary string to be quoted, some existing implementations handle a quoted boundary string incorrectly.
1265         </li>
1266         <li>A number of clients and servers were coded to an early draft of the byteranges specification to use a media type of multipart/x-byteranges<span id="rfc.iref.m.3"></span><span id="rfc.iref.m.4"></span>, which is almost, but not quite compatible with the version documented in HTTP/1.1.
1267         </li>
1268      </ol>
1269      <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a>&nbsp;<a id="changes.from.rfc.2616" href="#changes.from.rfc.2616">Changes from RFC 2616</a></h1>
1270      <p id="rfc.section.B.p.1">Introduce Range Specifier Registry. (<a href="#range.specifier.registry" title="Range Specifier Registry">Section&nbsp;2.1</a>)
1271      </p>
1272      <p id="rfc.section.B.p.2">Clarify that it is not ok to use a weak validator in a <a href="#status.206" class="smpl">206</a> response. (<a href="#status.206" id="rfc.xref.status.206.2" title="206 Partial Content">Section&nbsp;3.1</a>)
1273      </p>
1274      <p id="rfc.section.B.p.3">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;5</a>)
1275      </p>
1276      <p id="rfc.section.B.p.4">Clarify that multipart/byteranges can consist of a single part. (<a href="#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix&nbsp;A</a>)
1277      </p>
1278      <h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a>&nbsp;<a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1>
1279      <div id="rfc.figure.u.26"></div> <pre class="inline"><a href="#header.accept-ranges" class="smpl">Accept-Ranges</a> = acceptable-ranges
1280
1281<a href="#header.content-range" class="smpl">Content-Range</a> = byte-content-range-spec / other-content-range-spec
1282
1283<a href="#core.rules" class="smpl">HTTP-date</a> = &lt;HTTP-date, defined in [Part2], Section 5.1&gt;
1284
1285<a href="#header.if-range" class="smpl">If-Range</a> = entity-tag / HTTP-date
1286
1287<a href="#core.rules" class="smpl">OWS</a> = &lt;OWS, defined in [Part1], Section 3.2.1&gt;
1288
1289<a href="#range.retrieval.requests" class="smpl">Range</a> = byte-ranges-specifier / other-ranges-specifier
1290
1291<a href="#header.accept-ranges" class="smpl">acceptable-ranges</a> = ( *( "," OWS ) range-unit *( OWS "," [ OWS
1292 range-unit ] ) ) / "none"
1293
1294<a href="#header.content-range" class="smpl">byte-content-range-spec</a> = bytes-unit SP byte-range-resp-spec "/" (
1295 instance-length / "*" )
1296<a href="#header.content-range" class="smpl">byte-range-resp-spec</a> = ( first-byte-pos "-" last-byte-pos ) / "*"
1297<a href="#rule.ranges-specifier" class="smpl">byte-range-set</a> = *( "," OWS ) ( byte-range-spec /
1298 suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec /
1299 suffix-byte-range-spec ) ] )
1300<a href="#rule.ranges-specifier" class="smpl">byte-range-spec</a> = first-byte-pos "-" [ last-byte-pos ]
1301<a href="#rule.ranges-specifier" class="smpl">byte-ranges-specifier</a> = bytes-unit "=" byte-range-set
1302<a href="#range.units" class="smpl">bytes-unit</a> = "bytes"
1303
1304<a href="#abnf.dependencies" class="smpl">entity-tag</a> = &lt;entity-tag, defined in [Part4], Section 2.3&gt;
1305
1306<a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a> = 1*DIGIT
1307
1308<a href="#header.content-range" class="smpl">instance-length</a> = 1*DIGIT
1309
1310<a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a> = 1*DIGIT
1311
1312<a href="#header.content-range" class="smpl">other-content-range-spec</a> = other-range-unit SP other-range-resp-spec
1313<a href="#header.content-range" class="smpl">other-range-resp-spec</a> = *CHAR
1314<a href="#range.retrieval.requests" class="smpl">other-range-set</a> = 1*CHAR
1315<a href="#range.units" class="smpl">other-range-unit</a> = token
1316<a href="#range.retrieval.requests" class="smpl">other-ranges-specifier</a> = other-range-unit "=" other-range-set
1317
1318<a href="#range.units" class="smpl">range-unit</a> = bytes-unit / other-range-unit
1319
1320<a href="#rule.ranges-specifier" class="smpl">suffix-byte-range-spec</a> = "-" suffix-length
1321<a href="#rule.ranges-specifier" class="smpl">suffix-length</a> = 1*DIGIT
1322
1323<a href="#core.rules" class="smpl">token</a> = &lt;token, defined in [Part1], Section 3.2.4&gt;
1324</pre> <h1 id="rfc.section.D"><a href="#rfc.section.D">D.</a>&nbsp;<a id="change.log" href="#change.log">Change Log (to be removed by RFC Editor before publication)</a></h1>
1325      <p id="rfc.section.D.p.1">Changes up to the first Working Group Last Call draft are summarized in &lt;<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p5-range-19#appendix-D">http://tools.ietf.org/html/draft-ietf-httpbis-p5-range-19#appendix-D</a>&gt;.
1326      </p>
1327      <h2 id="rfc.section.D.1"><a href="#rfc.section.D.1">D.1</a>&nbsp;<a id="changes.since.19" href="#changes.since.19">Since draft-ietf-httpbis-p5-range-19</a></h2>
1328      <p id="rfc.section.D.1.p.1">Closed issues: </p>
1329      <ul>
1330         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/358">http://tools.ietf.org/wg/httpbis/trac/ticket/358</a>&gt;: "ABNF list expansion code problem"
1331         </li>
1332         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/361">http://tools.ietf.org/wg/httpbis/trac/ticket/361</a>&gt;: "ABNF requirements for recipients"
1333         </li>
1334         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/367">http://tools.ietf.org/wg/httpbis/trac/ticket/367</a>&gt;: "reserve 'none' as byte range unit"
1335         </li>
1336         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/368">http://tools.ietf.org/wg/httpbis/trac/ticket/368</a>&gt;: "note introduction of new IANA registries as normative changes"
1337         </li>
1338         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/369">http://tools.ietf.org/wg/httpbis/trac/ticket/369</a>&gt;: "range units vs leading zeroes vs size"
1339         </li>
1340      </ul>
1341      <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1>
1342      <p class="noprint"><a href="#rfc.index.2">2</a> <a href="#rfc.index.4">4</a> <a href="#rfc.index.A">A</a> <a href="#rfc.index.C">C</a> <a href="#rfc.index.G">G</a> <a href="#rfc.index.H">H</a> <a href="#rfc.index.I">I</a> <a href="#rfc.index.M">M</a> <a href="#rfc.index.P">P</a> <a href="#rfc.index.R">R</a> <a href="#rfc.index.S">S</a> 
1343      </p>
1344      <div class="print2col">
1345         <ul class="ind">
1346            <li><a id="rfc.index.2" href="#rfc.index.2"><b>2</b></a><ul>
1347                  <li>206 Partial Content (status code)&nbsp;&nbsp;<a href="#rfc.iref.3"><b>3.1</b></a>, <a href="#rfc.xref.status.206.1">6.1</a>, <a href="#rfc.xref.status.206.2">B</a></li>
1348               </ul>
1349            </li>
1350            <li><a id="rfc.index.4" href="#rfc.index.4"><b>4</b></a><ul>
1351                  <li>416 Requested Range Not Satisfiable (status code)&nbsp;&nbsp;<a href="#rfc.iref.4"><b>3.2</b></a>, <a href="#rfc.xref.status.416.1">6.1</a></li>
1352               </ul>
1353            </li>
1354            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
1355                  <li>Accept-Ranges header field&nbsp;&nbsp;<a href="#rfc.iref.a.1"><b>5.1</b></a>, <a href="#rfc.xref.header.accept-ranges.1">6.2</a>, <a href="#rfc.xref.header.accept-ranges.2">6.3</a></li>
1356               </ul>
1357            </li>
1358            <li><a id="rfc.index.C" href="#rfc.index.C"><b>C</b></a><ul>
1359                  <li>Content-Range header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-range.1">2</a>, <a href="#rfc.xref.header.content-range.2">3.1</a>, <a href="#rfc.xref.header.content-range.3">3.2</a>, <a href="#rfc.iref.c.1"><b>5.2</b></a>, <a href="#rfc.xref.header.content-range.4">6.2</a></li>
1360               </ul>
1361            </li>
1362            <li><a id="rfc.index.G" href="#rfc.index.G"><b>G</b></a><ul>
1363                  <li><tt>Grammar</tt>&nbsp;&nbsp;
1364                     <ul>
1365                        <li><tt>Accept-Ranges</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.4"><b>5.1</b></a></li>
1366                        <li><tt>acceptable-ranges</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>5.1</b></a></li>
1367                        <li><tt>byte-content-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>5.2</b></a></li>
1368                        <li><tt>byte-range-resp-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>5.2</b></a></li>
1369                        <li><tt>byte-range-set</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.13"><b>5.4.1</b></a></li>
1370                        <li><tt>byte-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.14"><b>5.4.1</b></a></li>
1371                        <li><tt>byte-ranges-specifier</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.12"><b>5.4.1</b></a></li>
1372                        <li><tt>bytes-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.2"><b>2</b></a></li>
1373                        <li><tt>Content-Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>5.2</b></a></li>
1374                        <li><tt>first-byte-pos</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.15"><b>5.4.1</b></a></li>
1375                        <li><tt>If-Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>5.3</b></a></li>
1376                        <li><tt>instance-length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>5.2</b></a></li>
1377                        <li><tt>last-byte-pos</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.16"><b>5.4.1</b></a></li>
1378                        <li><tt>other-range-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>2</b></a></li>
1379                        <li><tt>Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.19"><b>5.4.2</b></a></li>
1380                        <li><tt>range-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>2</b></a></li>
1381                        <li><tt>ranges-specifier</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.11"><b>5.4.1</b></a></li>
1382                        <li><tt>suffix-byte-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.17"><b>5.4.1</b></a></li>
1383                        <li><tt>suffix-length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.18"><b>5.4.1</b></a></li>
1384                     </ul>
1385                  </li>
1386               </ul>
1387            </li>
1388            <li><a id="rfc.index.H" href="#rfc.index.H"><b>H</b></a><ul>
1389                  <li>Header Fields&nbsp;&nbsp;
1390                     <ul>
1391                        <li>Accept-Ranges&nbsp;&nbsp;<a href="#rfc.iref.h.1"><b>5.1</b></a>, <a href="#rfc.xref.header.accept-ranges.1">6.2</a>, <a href="#rfc.xref.header.accept-ranges.2">6.3</a></li>
1392                        <li>Content-Range&nbsp;&nbsp;<a href="#rfc.xref.header.content-range.1">2</a>, <a href="#rfc.xref.header.content-range.2">3.1</a>, <a href="#rfc.xref.header.content-range.3">3.2</a>, <a href="#rfc.iref.h.2"><b>5.2</b></a>, <a href="#rfc.xref.header.content-range.4">6.2</a></li>
1393                        <li>If-Range&nbsp;&nbsp;<a href="#rfc.xref.header.if-range.1">3.1</a>, <a href="#rfc.xref.header.if-range.2">3.2</a>, <a href="#rfc.iref.h.3"><b>5.3</b></a>, <a href="#rfc.xref.header.if-range.3">5.4.2</a>, <a href="#rfc.xref.header.if-range.4">6.2</a></li>
1394                        <li>Range&nbsp;&nbsp;<a href="#rfc.xref.header.range.1">2</a>, <a href="#rfc.xref.header.range.2">2</a>, <a href="#rfc.xref.header.range.3">3.1</a>, <a href="#rfc.xref.header.range.4">3.2</a>, <a href="#rfc.iref.h.4"><b>5.4</b></a>, <a href="#rfc.xref.header.range.5">6.2</a></li>
1395                     </ul>
1396                  </li>
1397               </ul>
1398            </li>
1399            <li><a id="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul>
1400                  <li>If-Range header field&nbsp;&nbsp;<a href="#rfc.xref.header.if-range.1">3.1</a>, <a href="#rfc.xref.header.if-range.2">3.2</a>, <a href="#rfc.iref.i.1"><b>5.3</b></a>, <a href="#rfc.xref.header.if-range.3">5.4.2</a>, <a href="#rfc.xref.header.if-range.4">6.2</a></li>
1401               </ul>
1402            </li>
1403            <li><a id="rfc.index.M" href="#rfc.index.M"><b>M</b></a><ul>
1404                  <li>Media Type&nbsp;&nbsp;
1405                     <ul>
1406                        <li>multipart/byteranges&nbsp;&nbsp;<a href="#rfc.iref.m.1"><b>A</b></a></li>
1407                        <li>multipart/x-byteranges&nbsp;&nbsp;<a href="#rfc.iref.m.4">A</a></li>
1408                     </ul>
1409                  </li>
1410                  <li>multipart/byteranges Media Type&nbsp;&nbsp;<a href="#rfc.iref.m.2"><b>A</b></a></li>
1411                  <li>multipart/x-byteranges Media Type&nbsp;&nbsp;<a href="#rfc.iref.m.3">A</a></li>
1412               </ul>
1413            </li>
1414            <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul>
1415                  <li><em>Part1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1.1</a>, <a href="#rfc.xref.Part1.2">1.2</a>, <a href="#rfc.xref.Part1.3">1.2.1</a>, <a href="#rfc.xref.Part1.4">1.2.1</a>, <a href="#rfc.xref.Part1.5">1.2.1</a>, <a href="#rfc.xref.Part1.6">8</a>, <a href="#Part1"><b>9.1</b></a><ul>
1416                        <li><em>Section 1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.2">1.2</a></li>
1417                        <li><em>Section 2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1.1</a></li>
1418                        <li><em>Section 3.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.4">1.2.1</a></li>
1419                        <li><em>Section 3.2.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.5">1.2.1</a></li>
1420                        <li><em>Section 9</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.6">8</a></li>
1421                     </ul>
1422                  </li>
1423                  <li><em>Part2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.1">1.2.1</a>, <a href="#rfc.xref.Part2.2">1.2.1</a>, <a href="#Part2"><b>9.1</b></a><ul>
1424                        <li><em>Section 5.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.2">1.2.1</a></li>
1425                     </ul>
1426                  </li>
1427                  <li><em>Part4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">1.2.2</a>, <a href="#rfc.xref.Part4.2">4.2</a>, <a href="#rfc.xref.Part4.3">4.2</a>, <a href="#rfc.xref.Part4.4">5.3</a>, <a href="#rfc.xref.Part4.5">5.3</a>, <a href="#Part4"><b>9.1</b></a><ul>
1428                        <li><em>Section 2.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.3">4.2</a>, <a href="#rfc.xref.Part4.4">5.3</a>, <a href="#rfc.xref.Part4.5">5.3</a></li>
1429                        <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">1.2.2</a>, <a href="#rfc.xref.Part4.2">4.2</a></li>
1430                     </ul>
1431                  </li>
1432                  <li><em>Part6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">3.1</a>, <a href="#Part6"><b>9.1</b></a><ul>
1433                        <li><em>Section 4.1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part6.1">3.1</a></li>
1434                     </ul>
1435                  </li>
1436               </ul>
1437            </li>
1438            <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul>
1439                  <li>Range header field&nbsp;&nbsp;<a href="#rfc.xref.header.range.1">2</a>, <a href="#rfc.xref.header.range.2">2</a>, <a href="#rfc.xref.header.range.3">3.1</a>, <a href="#rfc.xref.header.range.4">3.2</a>, <a href="#rfc.iref.r.1"><b>5.4</b></a>, <a href="#rfc.xref.header.range.5">6.2</a></li>
1440                  <li><em>RFC2046</em>&nbsp;&nbsp;<a href="#RFC2046"><b>9.1</b></a>, <a href="#rfc.xref.RFC2046.1">A</a>, <a href="#rfc.xref.RFC2046.2">A</a><ul>
1441                        <li><em>Section 5.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.1">A</a></li>
1442                     </ul>
1443                  </li>
1444                  <li><em>RFC2119</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2119.1">1.1</a>, <a href="#RFC2119"><b>9.1</b></a></li>
1445                  <li><em>RFC2616</em>&nbsp;&nbsp;<a href="#RFC2616"><b>9.2</b></a></li>
1446                  <li><em>RFC3864</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.1">6.2</a>, <a href="#RFC3864"><b>9.2</b></a></li>
1447                  <li><em>RFC4288</em>&nbsp;&nbsp;<a href="#RFC4288"><b>9.2</b></a>, <a href="#rfc.xref.RFC4288.1">A</a></li>
1448                  <li><em>RFC5226</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">2.1</a>, <a href="#RFC5226"><b>9.2</b></a><ul>
1449                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">2.1</a></li>
1450                     </ul>
1451                  </li>
1452                  <li><em>RFC5234</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.1">1.2</a>, <a href="#rfc.xref.RFC5234.2">1.2</a>, <a href="#RFC5234"><b>9.1</b></a><ul>
1453                        <li><em>Appendix B.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.2">1.2</a></li>
1454                     </ul>
1455                  </li>
1456               </ul>
1457            </li>
1458            <li><a id="rfc.index.S" href="#rfc.index.S"><b>S</b></a><ul>
1459                  <li>Status Codes&nbsp;&nbsp;
1460                     <ul>
1461                        <li>206 Partial Content&nbsp;&nbsp;<a href="#rfc.iref.s.1"><b>3.1</b></a>, <a href="#rfc.xref.status.206.1">6.1</a>, <a href="#rfc.xref.status.206.2">B</a></li>
1462                        <li>416 Requested Range Not Satisfiable&nbsp;&nbsp;<a href="#rfc.iref.s.2"><b>3.2</b></a>, <a href="#rfc.xref.status.416.1">6.1</a></li>
1463                     </ul>
1464                  </li>
1465               </ul>
1466            </li>
1467         </ul>
1468      </div>
1469   </body>
1470</html>
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