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379</style><link rel="Contents" href="#rfc.toc">
380      <link rel="Author" href="#rfc.authors">
381      <link rel="Copyright" href="#rfc.copyrightnotice">
382      <link rel="Index" href="#rfc.index">
383      <link rel="Chapter" title="1 Introduction" href="#rfc.section.1">
384      <link rel="Chapter" title="2 Range Units" href="#rfc.section.2">
385      <link rel="Chapter" title="3 Status Code Definitions" href="#rfc.section.3">
386      <link rel="Chapter" title="4 Combining Ranges" href="#rfc.section.4">
387      <link rel="Chapter" title="5 Header Field Definitions" href="#rfc.section.5">
388      <link rel="Chapter" title="6 IANA Considerations" href="#rfc.section.6">
389      <link rel="Chapter" title="7 Security Considerations" href="#rfc.section.7">
390      <link rel="Chapter" title="8 Acknowledgments" href="#rfc.section.8">
391      <link rel="Chapter" href="#rfc.section.9" title="9 References">
392      <link rel="Appendix" title="A Internet Media Type multipart/byteranges" href="#rfc.section.A">
393      <link rel="Appendix" title="B Compatibility with Previous Versions" href="#rfc.section.B">
394      <link rel="Appendix" title="C Collected ABNF" href="#rfc.section.C">
395      <link rel="Appendix" title="D Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.D">
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397      <link rel="schema.dct" href="http://purl.org/dc/terms/">
398      <meta name="dct.creator" content="Fielding, R.">
399      <meta name="dct.creator" content="Gettys, J.">
400      <meta name="dct.creator" content="Mogul, J.">
401      <meta name="dct.creator" content="Frystyk, H.">
402      <meta name="dct.creator" content="Masinter, L.">
403      <meta name="dct.creator" content="Leach, P.">
404      <meta name="dct.creator" content="Berners-Lee, T.">
405      <meta name="dct.creator" content="Lafon, Y.">
406      <meta name="dct.creator" content="Reschke, J. F.">
407      <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p5-range-latest">
408      <meta name="dct.issued" scheme="ISO8601" content="2011-03-01">
409      <meta name="dct.replaces" content="urn:ietf:rfc:2616">
410      <meta name="dct.abstract" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia 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-specific requests and the rules for constructing and combining responses to those requests.">
411      <meta name="description" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia 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-specific requests and the rules for constructing and combining responses to those requests.">
412   </head>
413   <body>
414      <table class="header">
415         <tbody>
416            <tr>
417               <td class="left">HTTPbis Working Group</td>
418               <td class="right">R. Fielding, Editor</td>
419            </tr>
420            <tr>
421               <td class="left">Internet-Draft</td>
422               <td class="right">Adobe</td>
423            </tr>
424            <tr>
425               <td class="left">Obsoletes: <a href="http://tools.ietf.org/html/rfc2616">2616</a> (if approved)
426               </td>
427               <td class="right">J. Gettys</td>
428            </tr>
429            <tr>
430               <td class="left">Intended status: Standards Track</td>
431               <td class="right">Alcatel-Lucent</td>
432            </tr>
433            <tr>
434               <td class="left">Expires: September 2, 2011</td>
435               <td class="right">J. Mogul</td>
436            </tr>
437            <tr>
438               <td class="left"></td>
439               <td class="right">HP</td>
440            </tr>
441            <tr>
442               <td class="left"></td>
443               <td class="right">H. Frystyk</td>
444            </tr>
445            <tr>
446               <td class="left"></td>
447               <td class="right">Microsoft</td>
448            </tr>
449            <tr>
450               <td class="left"></td>
451               <td class="right">L. Masinter</td>
452            </tr>
453            <tr>
454               <td class="left"></td>
455               <td class="right">Adobe</td>
456            </tr>
457            <tr>
458               <td class="left"></td>
459               <td class="right">P. Leach</td>
460            </tr>
461            <tr>
462               <td class="left"></td>
463               <td class="right">Microsoft</td>
464            </tr>
465            <tr>
466               <td class="left"></td>
467               <td class="right">T. Berners-Lee</td>
468            </tr>
469            <tr>
470               <td class="left"></td>
471               <td class="right">W3C/MIT</td>
472            </tr>
473            <tr>
474               <td class="left"></td>
475               <td class="right">Y. Lafon, Editor</td>
476            </tr>
477            <tr>
478               <td class="left"></td>
479               <td class="right">W3C</td>
480            </tr>
481            <tr>
482               <td class="left"></td>
483               <td class="right">J. Reschke, Editor</td>
484            </tr>
485            <tr>
486               <td class="left"></td>
487               <td class="right">greenbytes</td>
488            </tr>
489            <tr>
490               <td class="left"></td>
491               <td class="right">March 1, 2011</td>
492            </tr>
493         </tbody>
494      </table>
495      <p class="title">HTTP/1.1, part 5: Range Requests and Partial Responses<br><span class="filename">draft-ietf-httpbis-p5-range-latest</span></p>
496      <h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1> 
497      <p>The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information
498         systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 5 of the
499         seven-part specification that defines the protocol referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616. Part
500         5 defines range-specific requests and the rules for constructing and combining responses to those requests.
501      </p> 
502      <h1 id="rfc.note.1"><a href="#rfc.note.1">Editorial Note (To be removed by RFC Editor)</a></h1> 
503      <p>Discussion of this draft should take place on the HTTPBIS working group mailing list (ietf-http-wg@w3.org). The current issues
504         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;.
505      </p> 
506      <p>The changes in this draft are summarized in <a href="#changes.since.12" title="Since draft-ietf-httpbis-p5-range-12">Appendix&nbsp;D.14</a>.
507      </p> 
508      <h1><a id="rfc.status" href="#rfc.status">Status of This Memo</a></h1>
509      <p>This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.</p>
510      <p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute
511         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>.
512      </p>
513      <p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other
514         documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work
515         in progress”.
516      </p>
517      <p>This Internet-Draft will expire on September 2, 2011.</p>
518      <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1>
519      <p>Copyright © 2011 IETF Trust and the persons identified as the document authors. All rights reserved.</p>
520      <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
521         and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License
522         text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified
523         BSD License.
524      </p>
525      <p>This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November
526         10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to
527         allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s)
528         controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative
529         works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate
530         it into languages other than English.
531      </p>
532      <hr class="noprint">
533      <h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1>
534      <ul class="toc">
535         <li>1.&nbsp;&nbsp;&nbsp;<a href="#introduction">Introduction</a><ul>
536               <li>1.1&nbsp;&nbsp;&nbsp;<a href="#intro.requirements">Requirements</a></li>
537               <li>1.2&nbsp;&nbsp;&nbsp;<a href="#notation">Syntax Notation</a><ul>
538                     <li>1.2.1&nbsp;&nbsp;&nbsp;<a href="#core.rules">Core Rules</a></li>
539                     <li>1.2.2&nbsp;&nbsp;&nbsp;<a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></li>
540                  </ul>
541               </li>
542            </ul>
543         </li>
544         <li>2.&nbsp;&nbsp;&nbsp;<a href="#range.units">Range Units</a><ul>
545               <li>2.1&nbsp;&nbsp;&nbsp;<a href="#range.specifier.registry">Range Specifier Registry</a></li>
546            </ul>
547         </li>
548         <li>3.&nbsp;&nbsp;&nbsp;<a href="#status.code.definitions">Status Code Definitions</a><ul>
549               <li>3.1&nbsp;&nbsp;&nbsp;<a href="#status.206">206 Partial Content</a></li>
550               <li>3.2&nbsp;&nbsp;&nbsp;<a href="#status.416">416 Requested Range Not Satisfiable</a></li>
551            </ul>
552         </li>
553         <li>4.&nbsp;&nbsp;&nbsp;<a href="#combining.byte.ranges">Combining Ranges</a></li>
554         <li>5.&nbsp;&nbsp;&nbsp;<a href="#header.fields">Header Field Definitions</a><ul>
555               <li>5.1&nbsp;&nbsp;&nbsp;<a href="#header.accept-ranges">Accept-Ranges</a></li>
556               <li>5.2&nbsp;&nbsp;&nbsp;<a href="#header.content-range">Content-Range</a></li>
557               <li>5.3&nbsp;&nbsp;&nbsp;<a href="#header.if-range">If-Range</a></li>
558               <li>5.4&nbsp;&nbsp;&nbsp;<a href="#header.range">Range</a><ul>
559                     <li>5.4.1&nbsp;&nbsp;&nbsp;<a href="#byte.ranges">Byte Ranges</a></li>
560                     <li>5.4.2&nbsp;&nbsp;&nbsp;<a href="#range.retrieval.requests">Range Retrieval Requests</a></li>
561                  </ul>
562               </li>
563            </ul>
564         </li>
565         <li>6.&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
566               <li>6.1&nbsp;&nbsp;&nbsp;<a href="#status.code.registration">Status Code Registration</a></li>
567               <li>6.2&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Header Field Registration</a></li>
568               <li>6.3&nbsp;&nbsp;&nbsp;<a href="#range.specifier.registration">Range Specifier Registration</a></li>
569            </ul>
570         </li>
571         <li>7.&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a></li>
572         <li>8.&nbsp;&nbsp;&nbsp;<a href="#ack">Acknowledgments</a></li>
573         <li>9.&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
574               <li>9.1&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
575               <li>9.2&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
576            </ul>
577         </li>
578         <li><a href="#rfc.authors">Authors' Addresses</a></li>
579         <li>A.&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.multipart.byteranges">Internet Media Type multipart/byteranges</a></li>
580         <li>B.&nbsp;&nbsp;&nbsp;<a href="#compatibility">Compatibility with Previous Versions</a><ul>
581               <li>B.1&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616">Changes from RFC 2616</a></li>
582            </ul>
583         </li>
584         <li>C.&nbsp;&nbsp;&nbsp;<a href="#collected.abnf">Collected ABNF</a></li>
585         <li>D.&nbsp;&nbsp;&nbsp;<a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul>
586               <li>D.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.1">Since RFC 2616</a></li>
587               <li>D.2&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.2">Since draft-ietf-httpbis-p5-range-00</a></li>
588               <li>D.3&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.3">Since draft-ietf-httpbis-p5-range-01</a></li>
589               <li>D.4&nbsp;&nbsp;&nbsp;<a href="#changes.since.02">Since draft-ietf-httpbis-p5-range-02</a></li>
590               <li>D.5&nbsp;&nbsp;&nbsp;<a href="#changes.since.03">Since draft-ietf-httpbis-p5-range-03</a></li>
591               <li>D.6&nbsp;&nbsp;&nbsp;<a href="#changes.since.04">Since draft-ietf-httpbis-p5-range-04</a></li>
592               <li>D.7&nbsp;&nbsp;&nbsp;<a href="#changes.since.05">Since draft-ietf-httpbis-p5-range-05</a></li>
593               <li>D.8&nbsp;&nbsp;&nbsp;<a href="#changes.since.06">Since draft-ietf-httpbis-p5-range-06</a></li>
594               <li>D.9&nbsp;&nbsp;&nbsp;<a href="#changes.since.07">Since draft-ietf-httpbis-p5-range-07</a></li>
595               <li>D.10&nbsp;&nbsp;&nbsp;<a href="#changes.since.08">Since draft-ietf-httpbis-p5-range-08</a></li>
596               <li>D.11&nbsp;&nbsp;&nbsp;<a href="#changes.since.09">Since draft-ietf-httpbis-p5-range-09</a></li>
597               <li>D.12&nbsp;&nbsp;&nbsp;<a href="#changes.since.10">Since draft-ietf-httpbis-p5-range-10</a></li>
598               <li>D.13&nbsp;&nbsp;&nbsp;<a href="#changes.since.11">Since draft-ietf-httpbis-p5-range-11</a></li>
599               <li>D.14&nbsp;&nbsp;&nbsp;<a href="#changes.since.12">Since draft-ietf-httpbis-p5-range-12</a></li>
600            </ul>
601         </li>
602         <li><a href="#rfc.index">Index</a></li>
603      </ul>
604      <h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a>&nbsp;<a id="introduction" href="#introduction">Introduction</a></h1>
605      <p id="rfc.section.1.p.1">HTTP clients often encounter interrupted data transfers as a result of cancelled requests or dropped connections. When a cache
606         has stored a partial representation, it is desirable to request the remainder of that representation in a subsequent request
607         rather than transfer the entire representation. There are also a number of Web applications that benefit from being able to
608         request only a subset of a larger representation, such as a single page of a very large document or only part of an image
609         to be rendered by a device with limited local storage.
610      </p>
611      <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
612         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
613         request without impacting interoperability. Partial responses are indicated by a distinct status code to not be mistaken for
614         full responses by intermediate caches that might not implement the feature.
615      </p>
616      <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
617         requests for byte ranges.
618      </p>
619      <h2 id="rfc.section.1.1"><a href="#rfc.section.1.1">1.1</a>&nbsp;<a id="intro.requirements" href="#intro.requirements">Requirements</a></h2>
620      <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"
621         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>.
622      </p>
623      <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the "MUST" or "REQUIRED" level requirements for the
624         protocols it implements. An implementation that satisfies all the "MUST" or "REQUIRED" level and all the "SHOULD" level requirements
625         for its protocols is said to be "unconditionally compliant"; one that satisfies all the "MUST" level requirements but not
626         all the "SHOULD" level requirements for its protocols is said to be "conditionally compliant".
627      </p>
628      <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>
629      <p id="rfc.section.1.2.p.1">This specification uses the ABNF syntax defined in <a href="p1-messaging.html#notation" title="Syntax Notation">Section 1.2</a> of <a href="#Part1" id="rfc.xref.Part1.1"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> (which extends the syntax defined in <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> with a list rule). <a href="#collected.abnf" title="Collected ABNF">Appendix&nbsp;C</a> shows the collected ABNF, with the list rule expanded.
630      </p>
631      <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
632         (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit sequence of data), SP (space), VCHAR (any visible USASCII character),
633         and WSP (whitespace).
634      </p>
635      <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>
636      <p id="rfc.section.1.2.1.p.1">The core rules below are defined in <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.2"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>:
637      </p>
638      <div id="rfc.figure.u.1"></div><pre class="inline">  <a href="#core.rules" class="smpl">token</a>      = &lt;token, defined in <a href="#Part1" id="rfc.xref.Part1.3"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
639  <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: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
640</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>
641      <p id="rfc.section.1.2.2.p.1">The ABNF rules below are defined in other parts:</p>
642      <div id="rfc.figure.u.2"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">HTTP-date</a>  = &lt;HTTP-date, defined in <a href="#Part1" id="rfc.xref.Part1.5"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#date.time.formats.full.date" title="Date/Time Formats: Full Date">Section 6.1</a>&gt;
643</pre><div id="rfc.figure.u.3"></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#entity.tags" title="Entity-Tags">Section 2</a>&gt;
644</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>
645      <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
646         uses range units in the Range (<a href="#header.range" id="rfc.xref.header.range.1" title="Range">Section&nbsp;5.4</a>) and Content-Range (<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.
647      </p>
648      <div id="rfc.figure.u.4"></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>
649  <a href="#range.units" class="smpl">bytes-unit</a>       = "bytes"
650  <a href="#range.units" class="smpl">other-range-unit</a> = <a href="#core.rules" class="smpl">token</a>
651</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
652         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>.
653      </p>
654      <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 Range 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.
655      </p>
656      <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>
657      <p id="rfc.section.2.1.p.1">The HTTP Ranger Specifier Registry defines the name space for the range specifier names.</p>
658      <p id="rfc.section.2.1.p.2">Registrations <em class="bcp14">MUST</em> include the following fields:
659      </p>
660      <ul>
661         <li>Name</li>
662         <li>Description</li>
663         <li>Pointer to specification text</li>
664      </ul>
665      <p id="rfc.section.2.1.p.3">Values to be added to this name space are subject to IETF review (<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>).
666      </p>
667      <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;.
668      </p>
669      <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>
670      <div id="rfc.iref.3"></div>
671      <div id="rfc.iref.s.1"></div>
672      <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>
673      <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 Range 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 If-Range 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.
674      </p>
675      <p id="rfc.section.3.1.p.2">The response <em class="bcp14">MUST</em> include the following header fields:
676      </p>
677      <ul>
678         <li>Either a Content-Range 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 Content-Type including Content-Range fields
679            for each part. If a Content-Length 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.
680         </li>
681         <li>Date</li>
682         <li>Cache-Control, ETag, Expires, Content-Location, Last-Modified, and/or Vary, if the header field would have been sent in a
683            200 response to the same request
684         </li>
685      </ul>
686      <p id="rfc.section.3.1.p.3">If the 206 response is the result of an If-Range request, the response <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 200 (OK) response to the same request.
687      </p>
688      <p id="rfc.section.3.1.p.4">A cache <em class="bcp14">MUST NOT</em> combine a 206 response with other previously cached content if the ETag or Last-Modified header fields do not match exactly,
689         see <a href="#combining.byte.ranges" title="Combining Ranges">Section&nbsp;4</a>.
690      </p>
691      <p id="rfc.section.3.1.p.5">A cache that does not support the Range and Content-Range header fields <em class="bcp14">MUST NOT</em> cache 206 (Partial Content) responses. Furthermore, if a response uses a range unit that is not understood by the cache, then
692         it <em class="bcp14">MUST NOT</em> be cached either.
693      </p>
694      <div id="rfc.iref.4"></div>
695      <div id="rfc.iref.s.2"></div>
696      <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>
697      <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 Range request-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
698         did not include an If-Range request-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
699         length of the selected resource.)
700      </p>
701      <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 Content-Range 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.
702      </p>
703      <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a id="combining.byte.ranges" href="#combining.byte.ranges">Combining Ranges</a></h1>
704      <p id="rfc.section.4.p.1">A response might transfer only a subrange of a representation, either because the request included one or more Range specifications,
705         or because a connection closed prematurely. After several such transfers, a cache might have received several ranges of the
706         same representation.
707      </p>
708      <p id="rfc.section.4.p.2">If a cache has a stored non-empty set of subranges for a representation, and an incoming response transfers another subrange,
709         the cache <em class="bcp14">MAY</em> combine the new subrange with the existing set if both the following conditions are met:
710      </p>
711      <ul>
712         <li>Both the incoming response and the cache entry have a cache validator.</li>
713         <li>The two cache validators match using the strong comparison function (see <a href="p4-conditional.html#weak.and.strong.validators" title="Weak and Strong Validators">Section 4</a> of <a href="#Part4" id="rfc.xref.Part4.2"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>).
714         </li>
715      </ul>
716      <p id="rfc.section.4.p.3">If either requirement is not met, the cache <em class="bcp14">MUST</em> use only the most recent partial response (based on the Date values transmitted with every response, and using the incoming
717         response if these values are equal or missing), and <em class="bcp14">MUST</em> discard the other partial information.
718      </p>
719      <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a id="header.fields" href="#header.fields">Header Field Definitions</a></h1>
720      <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>
721      <div id="rfc.iref.a.1"></div>
722      <div id="rfc.iref.h.1"></div>
723      <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>
724      <p id="rfc.section.5.1.p.1">The "Accept-Ranges" response-header field allows a resource to indicate its acceptance of range requests.</p>
725      <div id="rfc.figure.u.5"></div><pre class="inline"><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span>  <a href="#header.accept-ranges" class="smpl">Accept-Ranges</a>     = "Accept-Ranges" ":" <a href="#core.rules" class="smpl">OWS</a> <a href="#header.accept-ranges" class="smpl">Accept-Ranges-v</a>
726  <a href="#header.accept-ranges" class="smpl">Accept-Ranges-v</a>   = <a href="#header.accept-ranges" class="smpl">acceptable-ranges</a>
727  <a href="#header.accept-ranges" class="smpl">acceptable-ranges</a> = 1#<a href="#range.units" class="smpl">range-unit</a> / "none"
728</pre><p id="rfc.section.5.1.p.3">Origin servers that accept byte-range requests <em class="bcp14">MAY</em> send
729      </p>
730      <div id="rfc.figure.u.6"></div><pre class="text">  Accept-Ranges: bytes
731</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>.
732      </p>
733      <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
734      </p>
735      <div id="rfc.figure.u.7"></div><pre class="text">  Accept-Ranges: none
736</pre><p id="rfc.section.5.1.p.8">to advise the client not to attempt a range request.</p>
737      <div id="rfc.iref.c.1"></div>
738      <div id="rfc.iref.h.2"></div>
739      <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>
740      <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
741         body is intended to be applied.
742      </p>
743      <p id="rfc.section.5.2.p.2">Range units are defined in <a href="#range.units" title="Range Units">Section&nbsp;2</a>.
744      </p>
745      <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span>  <a href="#header.content-range" class="smpl">Content-Range</a> = "Content-Range" ":" <a href="#core.rules" class="smpl">OWS</a> <a href="#header.content-range" class="smpl">Content-Range-v</a>
746  <a href="#header.content-range" class="smpl">Content-Range-v</a> = <a href="#header.content-range" class="smpl">content-range-spec</a>
747 
748  <a href="#header.content-range" class="smpl">content-range-spec</a>      = <a href="#header.content-range" class="smpl">byte-content-range-spec</a>
749                          / <a href="#header.content-range" class="smpl">other-content-range-spec</a>
750  <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>
751                            <a href="#header.content-range" class="smpl">byte-range-resp-spec</a> "/"
752                            ( <a href="#header.content-range" class="smpl">instance-length</a> / "*" )
753 
754  <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>)
755                          / "*"
756                         
757  <a href="#header.content-range" class="smpl">instance-length</a>         = 1*<a href="#notation" class="smpl">DIGIT</a>
758 
759  <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>
760                             <a href="#header.content-range" class="smpl">other-range-resp-spec</a>
761  <a href="#header.content-range" class="smpl">other-range-resp-spec</a>    = *<a href="#notation" class="smpl">CHAR</a>
762</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
763         "*" character means that the instance-length is unknown at the time when the response was generated.
764      </p>
765      <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.
766      </p>
767      <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
768         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.
769      </p>
770      <p id="rfc.section.5.2.p.7">In the case of a byte range request: A server sending a response with status code 416 (Requested range not satisfiable) <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
771         selected resource. A response with status code 206 (Partial Content) <em class="bcp14">MUST NOT</em> include a Content-Range field with a byte-range-resp-spec of "*".
772      </p>
773      <p id="rfc.section.5.2.p.8">Examples of byte-content-range-spec values, assuming that the representation contains a total of 1234 bytes: </p>
774      <ul>
775         <li>The first 500 bytes:
776            <div id="rfc.figure.u.9"></div><pre class="text">  bytes 0-499/1234
777</pre> </li>
778         <li>The second 500 bytes:
779            <div id="rfc.figure.u.10"></div><pre class="text">  bytes 500-999/1234
780</pre> </li>
781         <li>All except for the first 500 bytes:
782            <div id="rfc.figure.u.11"></div><pre class="text">  bytes 500-1233/1234
783</pre> </li>
784         <li>The last 500 bytes:
785            <div id="rfc.figure.u.12"></div><pre class="text">  bytes 734-1233/1234
786</pre> </li>
787      </ul>
788      <p id="rfc.section.5.2.p.9">When an HTTP message includes the content of a single range (for example, a response to a request for a single range, or to
789         a request for a set of ranges that overlap without any holes), this content is transmitted with a Content-Range header field,
790         and a Content-Length header field showing the number of bytes actually transferred. For example,
791      </p>
792      <div id="rfc.figure.u.13"></div><pre class="text">  HTTP/1.1 206 Partial Content
793  Date: Wed, 15 Nov 1995 06:25:24 GMT
794  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
795  Content-Range: bytes 21010-47021/47022
796  Content-Length: 26012
797  Content-Type: image/gif
798</pre><p id="rfc.section.5.2.p.11">When an HTTP message includes the content of multiple ranges (for example, a response to a request for multiple non-overlapping
799         ranges), these are transmitted as a multipart message. The multipart media type used for this purpose is "multipart/byteranges"
800         as defined in <a href="#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix&nbsp;A</a>.
801      </p>
802      <p id="rfc.section.5.2.p.12">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.
803      </p>
804      <p id="rfc.section.5.2.p.13">When a client requests multiple ranges in one request, the server <em class="bcp14">SHOULD</em> return them in the order that they appeared in the request.
805      </p>
806      <p id="rfc.section.5.2.p.14">If the server ignores a byte-range-spec because it is syntactically invalid, the server <em class="bcp14">SHOULD</em> treat the request as if the invalid Range header field did not exist. (Normally, this means return a 200 response containing
807         the full representation).
808      </p>
809      <p id="rfc.section.5.2.p.15">If the server receives a request (other than one including an If-Range request-header field) with an unsatisfiable Range request-header
810         field (that is, all of whose byte-range-spec values have a first-byte-pos value greater than the current length of the selected
811         resource), it <em class="bcp14">SHOULD</em> return a response code of 416 (Requested range not satisfiable) (<a href="#status.416" id="rfc.xref.status.416.1" title="416 Requested Range Not Satisfiable">Section&nbsp;3.2</a>).
812      </p>
813      <div class="note" id="rfc.section.5.2.p.16"> 
814         <p> <b>Note:</b> Clients cannot depend on servers to send a 416 (Requested range not satisfiable) response instead of a 200 (OK) response for
815            an unsatisfiable Range request-header field, since not all servers implement this request-header field.
816         </p> 
817      </div>
818      <div id="rfc.iref.i.1"></div>
819      <div id="rfc.iref.h.3"></div>
820      <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>
821      <p id="rfc.section.5.3.p.1">If a client has a partial copy of a representation in its cache, and wishes to have an up-to-date copy of the entire representation
822         in its cache, it could use the Range request-header field with a conditional GET (using either or both of If-Unmodified-Since
823         and If-Match.) However, if the condition fails because the representation has been modified, the client would then have to
824         make a second request to obtain the entire current representation.
825      </p>
826      <p id="rfc.section.5.3.p.2">The "If-Range" request-header field allows a client to "short-circuit" the second request. Informally, its meaning is "if
827         the representation is unchanged, send me the part(s) that I am missing; otherwise, send me the entire new representation".
828      </p>
829      <div id="rfc.figure.u.14"></div><pre class="inline"><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span>  <a href="#header.if-range" class="smpl">If-Range</a>   = "If-Range" ":" <a href="#core.rules" class="smpl">OWS</a> <a href="#header.if-range" class="smpl">If-Range-v</a>
830  <a href="#header.if-range" class="smpl">If-Range-v</a> = <a href="#abnf.dependencies" class="smpl">entity-tag</a> / <a href="#abnf.dependencies" class="smpl">HTTP-date</a>
831</pre><p id="rfc.section.5.3.p.4">If the client has no entity-tag for a representation, but does have a Last-Modified date, it <em class="bcp14">MAY</em> use that date in an If-Range header field. (The server can distinguish between a valid HTTP-date and any form of entity-tag
832         by examining no more than two characters.) The If-Range header field <em class="bcp14">SHOULD</em> only be used together with a Range header field, and <em class="bcp14">MUST</em> be ignored if the request does not include a Range header field, or if the server does not support the sub-range operation.
833      </p>
834      <p id="rfc.section.5.3.p.5">If the entity-tag given in the If-Range header field matches the current cache validator for the representation, then the
835         server <em class="bcp14">SHOULD</em> provide the specified sub-range of the representation using a 206 (Partial Content) response. If the cache validator does
836         not match, then the server <em class="bcp14">SHOULD</em> return the entire representation using a 200 (OK) response.
837      </p>
838      <div id="rfc.iref.r.1"></div>
839      <div id="rfc.iref.h.4"></div>
840      <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>
841      <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>
842      <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
843         representation. (However, not all clients and servers need to support byte-range operations.)
844      </p>
845      <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
846         message-body).
847      </p>
848      <div id="rule.ranges-specifier">
849         <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.
850         </p>
851      </div>
852      <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.15"></span><span id="rfc.iref.g.16"></span><span id="rfc.iref.g.17"></span><span id="rfc.iref.g.18"></span><span id="rfc.iref.g.19"></span><span id="rfc.iref.g.20"></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>
853  <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> )
854  <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> ]
855  <a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a>  = 1*<a href="#notation" class="smpl">DIGIT</a>
856  <a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a>   = 1*<a href="#notation" class="smpl">DIGIT</a>
857</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
858         gives the byte-offset of the last byte in the range; that is, the byte positions specified are inclusive. Byte offsets start
859         at zero.
860      </p>
861      <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
862         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.
863      </p>
864      <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
865         body, last-byte-pos is taken to be equal to one less than the current length of the representation in bytes.
866      </p>
867      <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>
868      <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.21"></span><span id="rfc.iref.g.22"></span>  <a href="#rule.ranges-specifier" class="smpl">suffix-byte-range-spec</a> = "-" <a href="#rule.ranges-specifier" class="smpl">suffix-length</a>
869  <a href="#rule.ranges-specifier" class="smpl">suffix-length</a> = 1*<a href="#notation" class="smpl">DIGIT</a>
870</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
871         value. (That is, this form specifies the last N bytes of a representation.) If the representation is shorter than the specified
872         suffix-length, the entire representation is used.
873      </p>
874      <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
875         length of the representation, or at least one suffix-byte-range-spec with a non-zero suffix-length, then the byte-range-set
876         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 416 (Requested range not satisfiable) status code. Otherwise, the server <em class="bcp14">SHOULD</em> return a response with a 206 (Partial Content) status code containing the satisfiable ranges of the representation.
877      </p>
878      <p id="rfc.section.5.4.1.p.12">Examples of byte-ranges-specifier values (assuming a representation of length 10000): </p>
879      <ul>
880         <li>The first 500 bytes (byte offsets 0-499, inclusive):
881            <div id="rfc.figure.u.17"></div><pre class="text">  bytes=0-499
882</pre> </li>
883         <li>The second 500 bytes (byte offsets 500-999, inclusive):
884            <div id="rfc.figure.u.18"></div><pre class="text">  bytes=500-999
885</pre> </li>
886         <li>The final 500 bytes (byte offsets 9500-9999, inclusive):
887            <div id="rfc.figure.u.19"></div><pre class="text">  bytes=-500
888</pre> Or: <div id="rfc.figure.u.20"></div><pre class="text">  bytes=9500-
889</pre> </li>
890         <li>The first and last bytes only (bytes 0 and 9999):
891            <div id="rfc.figure.u.21"></div><pre class="text">  bytes=0-0,-1
892</pre> </li>
893         <li>Several legal but not canonical specifications of the second 500 bytes (byte offsets 500-999, inclusive):
894            <div id="rfc.figure.u.22"></div><pre class="text">  bytes=500-600,601-999
895  bytes=500-700,601-999
896</pre> </li>
897      </ul>
898      <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>
899      <p id="rfc.section.5.4.2.p.1">The "Range" request-header field defines the GET method (conditional or not) to request one or more sub-ranges of the response
900         representation body, instead of the entire representation body.
901      </p>
902      <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.23"></span>  <a href="#range.retrieval.requests" class="smpl">Range</a>   = "Range" ":" <a href="#core.rules" class="smpl">OWS</a> <a href="#range.retrieval.requests" class="smpl">Range-v</a>
903  <a href="#range.retrieval.requests" class="smpl">Range-v</a> = <a href="#rule.ranges-specifier" class="smpl">byte-ranges-specifier</a>
904          / <a href="#range.retrieval.requests" class="smpl">other-ranges-specifier</a>
905  <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>
906  <a href="#range.retrieval.requests" class="smpl">other-range-set</a> = 1*<a href="#notation" class="smpl">CHAR</a>
907</pre><p id="rfc.section.5.4.2.p.3">A server <em class="bcp14">MAY</em> ignore the Range header field. However, HTTP/1.1 origin servers and intermediate caches ought to support byte ranges when
908         possible, since Range supports efficient recovery from partially failed transfers, and supports efficient partial retrieval
909         of large representations.
910      </p>
911      <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>
912      <ul>
913         <li>The presence of a Range header field in an unconditional GET modifies what is returned if the GET is otherwise successful.
914            In other words, the response carries a status code of 206 (Partial Content) instead of 200 (OK).
915         </li>
916         <li>The presence of a Range header field in a conditional GET (a request using one or both of If-Modified-Since and If-None-Match,
917            or one or both of If-Unmodified-Since and If-Match) modifies what is returned if the GET is otherwise successful and the condition
918            is true. It does not affect the 304 (Not Modified) response returned if the conditional is false.
919         </li>
920      </ul>
921      <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.
922      </p>
923      <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
924         representation in reply, it <em class="bcp14">MAY</em> only return the requested range to its client.
925      </p>
926      <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
927      <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>
928      <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:
929      </p>
930      <div id="rfc.table.1">
931         <div id="iana.status.code.registration.table"></div>
932         <table class="tt full left" cellpadding="3" cellspacing="0">
933            <thead>
934               <tr>
935                  <th>Value</th>
936                  <th>Description</th>
937                  <th>Reference</th>
938               </tr>
939            </thead>
940            <tbody>
941               <tr>
942                  <td class="left">206</td>
943                  <td class="left">Partial Content</td>
944                  <td class="left"> <a href="#status.206" id="rfc.xref.status.206.1" title="206 Partial Content">Section&nbsp;3.1</a> 
945                  </td>
946               </tr>
947               <tr>
948                  <td class="left">416</td>
949                  <td class="left">Requested Range Not Satisfiable</td>
950                  <td class="left"> <a href="#status.416" id="rfc.xref.status.416.2" title="416 Requested Range Not Satisfiable">Section&nbsp;3.2</a> 
951                  </td>
952               </tr>
953            </tbody>
954         </table>
955      </div>
956      <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>
957      <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>):
958      </p>
959      <div id="rfc.table.2">
960         <div id="iana.header.registration.table"></div>
961         <table class="tt full left" cellpadding="3" cellspacing="0">
962            <thead>
963               <tr>
964                  <th>Header Field Name</th>
965                  <th>Protocol</th>
966                  <th>Status</th>
967                  <th>Reference</th>
968               </tr>
969            </thead>
970            <tbody>
971               <tr>
972                  <td class="left">Accept-Ranges</td>
973                  <td class="left">http</td>
974                  <td class="left">standard</td>
975                  <td class="left"> <a href="#header.accept-ranges" id="rfc.xref.header.accept-ranges.1" title="Accept-Ranges">Section&nbsp;5.1</a> 
976                  </td>
977               </tr>
978               <tr>
979                  <td class="left">Content-Range</td>
980                  <td class="left">http</td>
981                  <td class="left">standard</td>
982                  <td class="left"> <a href="#header.content-range" id="rfc.xref.header.content-range.4" title="Content-Range">Section&nbsp;5.2</a> 
983                  </td>
984               </tr>
985               <tr>
986                  <td class="left">If-Range</td>
987                  <td class="left">http</td>
988                  <td class="left">standard</td>
989                  <td class="left"> <a href="#header.if-range" id="rfc.xref.header.if-range.4" title="If-Range">Section&nbsp;5.3</a> 
990                  </td>
991               </tr>
992               <tr>
993                  <td class="left">Range</td>
994                  <td class="left">http</td>
995                  <td class="left">standard</td>
996                  <td class="left"> <a href="#header.range" id="rfc.xref.header.range.5" title="Range">Section&nbsp;5.4</a> 
997                  </td>
998               </tr>
999            </tbody>
1000         </table>
1001      </div>
1002      <p id="rfc.section.6.2.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
1003      <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>
1004      <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.
1005      </p>
1006      <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:
1007      </p>
1008      <div id="rfc.table.3">
1009         <div id="iana.range.specifiers.table"></div>
1010         <table class="tt full left" cellpadding="3" cellspacing="0">
1011            <thead>
1012               <tr>
1013                  <th>Range Specifier Name</th>
1014                  <th>Description</th>
1015                  <th>Reference</th>
1016               </tr>
1017            </thead>
1018            <tbody>
1019               <tr>
1020                  <td class="left">bytes</td>
1021                  <td class="left">a range of octets</td>
1022                  <td class="left">(this specification)</td>
1023               </tr>
1024            </tbody>
1025         </table>
1026      </div>
1027      <p id="rfc.section.6.3.p.3">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
1028      <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="security.considerations" href="#security.considerations">Security Considerations</a></h1>
1029      <p id="rfc.section.7.p.1">No additional security considerations have been identified beyond those applicable to HTTP in general <a href="#Part1" id="rfc.xref.Part1.6"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>.
1030      </p>
1031      <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a id="ack" href="#ack">Acknowledgments</a></h1>
1032      <p id="rfc.section.8.p.1">Most of the specification of ranges is based on work originally done by Ari Luotonen and John Franks, with additional input
1033         from Steve Zilles, Daniel W. Connolly, Roy T. Fielding, Jim Gettys, Martin Hamilton, Koen Holtman, Shel Kaplan, Paul Leach,
1034         Alex Lopez-Ortiz, Larry Masinter, Jeff Mogul, Lou Montulli, David W. Morris, Luigi Rizzo, and Bill Weihl.
1035      </p>
1036      <h1 id="rfc.references"><a id="rfc.section.9" href="#rfc.section.9">9.</a> References
1037      </h1>
1038      <h2 id="rfc.references.1"><a href="#rfc.section.9.1" id="rfc.section.9.1">9.1</a> Normative References
1039      </h2>
1040      <table>         
1041         <tr>
1042            <td class="reference"><b id="Part1">[Part1]</b></td>
1043            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:jg@freedesktop.org" title="Alcatel-Lucent Bell Labs">Gettys, J.</a>, <a href="mailto:JeffMogul@acm.org" title="Hewlett-Packard Company">Mogul, J.</a>, <a href="mailto:henrikn@microsoft.com" title="Microsoft Corporation">Frystyk, H.</a>, <a href="mailto:LMM@acm.org" title="Adobe Systems Incorporated">Masinter, L.</a>, <a href="mailto:paulle@microsoft.com" title="Microsoft Corporation">Leach, P.</a>, <a href="mailto:timbl@w3.org" title="World Wide Web Consortium">Berners-Lee, T.</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: URIs, Connections, and Message Parsing</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p1-messaging-latest (work in progress), March&nbsp;2011.
1044            </td>
1045         </tr>
1046         <tr>
1047            <td class="reference"><b id="Part4">[Part4]</b></td>
1048            <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:jg@freedesktop.org" title="Alcatel-Lucent Bell Labs">Gettys, J.</a>, <a href="mailto:JeffMogul@acm.org" title="Hewlett-Packard Company">Mogul, J.</a>, <a href="mailto:henrikn@microsoft.com" title="Microsoft Corporation">Frystyk, H.</a>, <a href="mailto:LMM@acm.org" title="Adobe Systems Incorporated">Masinter, L.</a>, <a href="mailto:paulle@microsoft.com" title="Microsoft Corporation">Leach, P.</a>, <a href="mailto:timbl@w3.org" title="World Wide Web Consortium">Berners-Lee, T.</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), March&nbsp;2011.
1049            </td>
1050         </tr>
1051         <tr>
1052            <td class="reference"><b id="RFC2046">[RFC2046]</b></td>
1053            <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.
1054            </td>
1055         </tr>
1056         <tr>
1057            <td class="reference"><b id="RFC2119">[RFC2119]</b></td>
1058            <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.
1059            </td>
1060         </tr>
1061         <tr>
1062            <td class="reference"><b id="RFC5234">[RFC5234]</b></td>
1063            <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.
1064            </td>
1065         </tr>
1066      </table>
1067      <h2 id="rfc.references.2"><a href="#rfc.section.9.2" id="rfc.section.9.2">9.2</a> Informative References
1068      </h2>
1069      <table>       
1070         <tr>
1071            <td class="reference"><b id="RFC2616">[RFC2616]</b></td>
1072            <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.
1073            </td>
1074         </tr>
1075         <tr>
1076            <td class="reference"><b id="RFC3864">[RFC3864]</b></td>
1077            <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.
1078            </td>
1079         </tr>
1080         <tr>
1081            <td class="reference"><b id="RFC4288">[RFC4288]</b></td>
1082            <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.
1083            </td>
1084         </tr>
1085         <tr>
1086            <td class="reference"><b id="RFC5226">[RFC5226]</b></td>
1087            <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.
1088            </td>
1089         </tr>
1090      </table>
1091      <div class="avoidbreak">
1092         <h1 id="rfc.authors"><a href="#rfc.authors">Authors' Addresses</a></h1>
1093         <address class="vcard"><span class="vcardline"><span class="fn">Roy T. Fielding</span>
1094               (editor)
1095               <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>
1096         <address class="vcard"><span class="vcardline"><span class="fn">Jim Gettys</span><span class="n hidden"><span class="family-name">Gettys</span><span class="given-name">Jim</span></span></span><span class="org vcardline">Alcatel-Lucent Bell Labs</span><span class="adr"><span class="street-address vcardline">21 Oak Knoll Road</span><span class="vcardline"><span class="locality">Carlisle</span>, <span class="region">MA</span>&nbsp;<span class="postal-code">01741</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:jg@freedesktop.org"><span class="email">jg@freedesktop.org</span></a></span><span class="vcardline">URI: <a href="http://gettys.wordpress.com/" class="url">http://gettys.wordpress.com/</a></span></address>
1097         <address class="vcard"><span class="vcardline"><span class="fn">Jeffrey C. Mogul</span><span class="n hidden"><span class="family-name">Mogul</span><span class="given-name">Jeffrey C.</span></span></span><span class="org vcardline">Hewlett-Packard Company</span><span class="adr"><span class="street-address vcardline">HP Labs, Large Scale Systems Group</span><span class="street-address vcardline">1501 Page Mill Road, MS 1177</span><span class="vcardline"><span class="locality">Palo Alto</span>, <span class="region">CA</span>&nbsp;<span class="postal-code">94304</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:JeffMogul@acm.org"><span class="email">JeffMogul@acm.org</span></a></span></address>
1098         <address class="vcard"><span class="vcardline"><span class="fn">Henrik Frystyk Nielsen</span><span class="n hidden"><span class="family-name">Frystyk</span></span></span><span class="org vcardline">Microsoft Corporation</span><span class="adr"><span class="street-address vcardline">1 Microsoft Way</span><span class="vcardline"><span class="locality">Redmond</span>, <span class="region">WA</span>&nbsp;<span class="postal-code">98052</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:henrikn@microsoft.com"><span class="email">henrikn@microsoft.com</span></a></span></address>
1099         <address class="vcard"><span class="vcardline"><span class="fn">Larry Masinter</span><span class="n hidden"><span class="family-name">Masinter</span><span class="given-name">Larry</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:LMM@acm.org"><span class="email">LMM@acm.org</span></a></span><span class="vcardline">URI: <a href="http://larry.masinter.net/" class="url">http://larry.masinter.net/</a></span></address>
1100         <address class="vcard"><span class="vcardline"><span class="fn">Paul J. Leach</span><span class="n hidden"><span class="family-name">Leach</span><span class="given-name">Paul J.</span></span></span><span class="org vcardline">Microsoft Corporation</span><span class="adr"><span class="street-address vcardline">1 Microsoft Way</span><span class="vcardline"><span class="locality">Redmond</span>, <span class="region">WA</span>&nbsp;<span class="postal-code">98052</span></span></span><span class="vcardline">Email: <a href="mailto:paulle@microsoft.com"><span class="email">paulle@microsoft.com</span></a></span></address>
1101         <address class="vcard"><span class="vcardline"><span class="fn">Tim Berners-Lee</span><span class="n hidden"><span class="family-name">Berners-Lee</span><span class="given-name">Tim</span></span></span><span class="org vcardline">World Wide Web Consortium</span><span class="adr"><span class="street-address vcardline">MIT Computer Science and Artificial Intelligence Laboratory</span><span class="street-address vcardline">The Stata Center, Building 32</span><span class="street-address vcardline">32 Vassar Street</span><span class="vcardline"><span class="locality">Cambridge</span>, <span class="region">MA</span>&nbsp;<span class="postal-code">02139</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">Email: <a href="mailto:timbl@w3.org"><span class="email">timbl@w3.org</span></a></span><span class="vcardline">URI: <a href="http://www.w3.org/People/Berners-Lee/" class="url">http://www.w3.org/People/Berners-Lee/</a></span></address>
1102         <address class="vcard"><span class="vcardline"><span class="fn">Yves Lafon</span>
1103               (editor)
1104               <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>
1105         <address class="vcard"><span class="vcardline"><span class="fn">Julian F. Reschke</span>
1106               (editor)
1107               <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 tel">Phone: <a href="tel:+492512807760"><span class="value">+49 251 2807760</span></a></span><span class="vcardline tel"><span class="type">Fax</span>: <a href="fax:+492512807761"><span class="value">+49 251 2807761</span></a></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>
1108      </div>
1109      <div id="rfc.iref.m.1"></div>
1110      <div id="rfc.iref.m.2"></div>
1111      <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>
1112      <p id="rfc.section.A.p.1">When an HTTP 206 (Partial Content) response message includes the content of multiple ranges (a response to a request for multiple
1113         non-overlapping ranges), these 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>.
1114      </p>
1115      <div class="note" id="rfc.section.A.p.2"> 
1116         <p> <b>Note:</b> Despite the name "multipart/byteranges" is not limited to the byte ranges only.
1117         </p> 
1118      </div>
1119      <p id="rfc.section.A.p.3">The multipart/byteranges media type includes one or more parts, each with its own Content-Type and Content-Range fields. The
1120         required boundary parameter specifies the boundary string used to separate each body-part.
1121      </p>
1122      <p id="rfc.section.A.p.4"> </p>
1123      <dl>
1124         <dt>Type name:</dt>
1125         <dd>multipart</dd>
1126         <dt>Subtype name:</dt>
1127         <dd>byteranges</dd>
1128         <dt>Required parameters:</dt>
1129         <dd>boundary</dd>
1130         <dt>Optional parameters:</dt>
1131         <dd>none</dd>
1132         <dt>Encoding considerations:</dt>
1133         <dd>only "7bit", "8bit", or "binary" are permitted</dd>
1134         <dt>Security considerations:</dt>
1135         <dd>none</dd>
1136         <dt>Interoperability considerations:</dt>
1137         <dd>none</dd>
1138         <dt>Published specification:</dt>
1139         <dd>This specification (see <a href="#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix&nbsp;A</a>).
1140         </dd>
1141         <dt>Applications that use this media type:</dt>
1142         <dt>Additional information:</dt>
1143         <dd> 
1144            <dl>
1145               <dt>Magic number(s):</dt>
1146               <dd>none</dd>
1147               <dt>File extension(s):</dt>
1148               <dd>none</dd>
1149               <dt>Macintosh file type code(s):</dt>
1150               <dd>none</dd>
1151            </dl> 
1152         </dd>
1153         <dt>Person and email address to contact for further information:</dt>
1154         <dd>See Authors Section.</dd>
1155         <dt>Intended usage:</dt>
1156         <dd>COMMON</dd>
1157         <dt>Restrictions on usage:</dt>
1158         <dd>none</dd>
1159         <dt>Author/Change controller:</dt>
1160         <dd>IESG</dd>
1161      </dl>
1162      <div id="rfc.figure.u.24"></div>
1163      <p>For example:</p><pre class="text">  HTTP/1.1 206 Partial Content
1164  Date: Wed, 15 Nov 1995 06:25:24 GMT
1165  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1166  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1167 
1168  --THIS_STRING_SEPARATES
1169  Content-type: application/pdf
1170  Content-range: bytes 500-999/8000
1171 
1172  ...the first range...
1173  --THIS_STRING_SEPARATES
1174  Content-type: application/pdf
1175  Content-range: bytes 7000-7999/8000
1176 
1177  ...the second range
1178  --THIS_STRING_SEPARATES--
1179</pre><div id="rfc.figure.u.25"></div>
1180      <p>Other example:</p>  <pre class="text">  HTTP/1.1 206 Partial Content
1181  Date: Tue, 14 Nov 1995 06:25:24 GMT
1182  Last-Modified: Tue, 14 July 04:58:08 GMT
1183  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1184 
1185  --THIS_STRING_SEPARATES
1186  Content-type: video/example
1187  Content-range: exampleunit 1.2-4.3/25
1188 
1189  ...the first range...
1190  --THIS_STRING_SEPARATES
1191  Content-type: video/example
1192  Content-range: exampleunit 11.2-14.3/25
1193 
1194  ...the second range
1195  --THIS_STRING_SEPARATES--
1196</pre> <p id="rfc.section.A.p.7">Notes: </p>
1197      <ol>
1198         <li>Additional CRLFs <em class="bcp14">MAY</em> precede the first boundary string in the body.
1199         </li>
1200         <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.
1201         </li>
1202         <li>A number of browsers 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.
1203         </li>
1204      </ol>
1205      <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a>&nbsp;<a id="compatibility" href="#compatibility">Compatibility with Previous Versions</a></h1>
1206      <h2 id="rfc.section.B.1"><a href="#rfc.section.B.1">B.1</a>&nbsp;<a id="changes.from.rfc.2616" href="#changes.from.rfc.2616">Changes from RFC 2616</a></h2>
1207      <p id="rfc.section.B.1.p.1">Clarify that it is not ok to use a weak cache validator in a 206 response. (<a href="#status.206" id="rfc.xref.status.206.2" title="206 Partial Content">Section&nbsp;3.1</a>)
1208      </p>
1209      <p id="rfc.section.B.1.p.2">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>)
1210      </p>
1211      <h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a>&nbsp;<a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1>
1212      <div id="rfc.figure.u.26"></div> <pre class="inline"><a href="#header.accept-ranges" class="smpl">Accept-Ranges</a> = "Accept-Ranges:" OWS Accept-Ranges-v
1213<a href="#header.accept-ranges" class="smpl">Accept-Ranges-v</a> = acceptable-ranges
1214
1215<a href="#header.content-range" class="smpl">Content-Range</a> = "Content-Range:" OWS Content-Range-v
1216<a href="#header.content-range" class="smpl">Content-Range-v</a> = content-range-spec
1217
1218<a href="#abnf.dependencies" class="smpl">HTTP-date</a> = &lt;HTTP-date, defined in [Part1], Section 6.1&gt;
1219
1220<a href="#header.if-range" class="smpl">If-Range</a> = "If-Range:" OWS If-Range-v
1221<a href="#header.if-range" class="smpl">If-Range-v</a> = entity-tag / HTTP-date
1222
1223<a href="#core.rules" class="smpl">OWS</a> = &lt;OWS, defined in [Part1], Section 1.2.2&gt;
1224
1225<a href="#range.retrieval.requests" class="smpl">Range</a> = "Range:" OWS Range-v
1226<a href="#range.retrieval.requests" class="smpl">Range-v</a> = byte-ranges-specifier / other-ranges-specifier
1227
1228<a href="#header.accept-ranges" class="smpl">acceptable-ranges</a> = ( *( "," OWS ) range-unit *( OWS "," [ OWS
1229 range-unit ] ) ) / "none"
1230
1231<a href="#header.content-range" class="smpl">byte-content-range-spec</a> = bytes-unit SP byte-range-resp-spec "/" (
1232 instance-length / "*" )
1233<a href="#header.content-range" class="smpl">byte-range-resp-spec</a> = ( first-byte-pos "-" last-byte-pos ) / "*"
1234<a href="#rule.ranges-specifier" class="smpl">byte-range-set</a> = ( *( "," OWS ) byte-range-spec ) / (
1235 suffix-byte-range-spec *( OWS "," [ ( OWS byte-range-spec ) /
1236 suffix-byte-range-spec ] ) )
1237<a href="#rule.ranges-specifier" class="smpl">byte-range-spec</a> = first-byte-pos "-" [ last-byte-pos ]
1238<a href="#rule.ranges-specifier" class="smpl">byte-ranges-specifier</a> = bytes-unit "=" byte-range-set
1239<a href="#range.units" class="smpl">bytes-unit</a> = "bytes"
1240
1241<a href="#header.content-range" class="smpl">content-range-spec</a> = byte-content-range-spec /
1242 other-content-range-spec
1243
1244<a href="#abnf.dependencies" class="smpl">entity-tag</a> = &lt;entity-tag, defined in [Part4], Section 2&gt;
1245
1246<a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a> = 1*DIGIT
1247
1248<a href="#header.content-range" class="smpl">instance-length</a> = 1*DIGIT
1249
1250<a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a> = 1*DIGIT
1251
1252<a href="#header.content-range" class="smpl">other-content-range-spec</a> = other-range-unit SP other-range-resp-spec
1253<a href="#header.content-range" class="smpl">other-range-resp-spec</a> = *CHAR
1254<a href="#range.retrieval.requests" class="smpl">other-range-set</a> = 1*CHAR
1255<a href="#range.units" class="smpl">other-range-unit</a> = token
1256<a href="#range.retrieval.requests" class="smpl">other-ranges-specifier</a> = other-range-unit "=" other-range-set
1257
1258<a href="#range.units" class="smpl">range-unit</a> = bytes-unit / other-range-unit
1259
1260<a href="#rule.ranges-specifier" class="smpl">suffix-byte-range-spec</a> = "-" suffix-length
1261<a href="#rule.ranges-specifier" class="smpl">suffix-length</a> = 1*DIGIT
1262
1263<a href="#core.rules" class="smpl">token</a> = &lt;token, defined in [Part1], Section 1.2.2&gt;
1264</pre> <div id="rfc.figure.u.27"></div>
1265      <p>ABNF diagnostics:</p><pre class="inline">; Accept-Ranges defined but not used
1266; Content-Range defined but not used
1267; If-Range defined but not used
1268; Range defined but not used
1269</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>
1270      <h2 id="rfc.section.D.1"><a href="#rfc.section.D.1">D.1</a>&nbsp;Since RFC 2616
1271      </h2>
1272      <p id="rfc.section.D.1.p.1">Extracted relevant partitions from <a href="#RFC2616" id="rfc.xref.RFC2616.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
1273      </p>
1274      <h2 id="rfc.section.D.2"><a href="#rfc.section.D.2">D.2</a>&nbsp;Since draft-ietf-httpbis-p5-range-00
1275      </h2>
1276      <p id="rfc.section.D.2.p.1">Closed issues: </p>
1277      <ul>
1278         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/18">http://tools.ietf.org/wg/httpbis/trac/ticket/18</a>&gt;: "Cache validators in 206 responses" (&lt;<a href="http://purl.org/NET/http-errata#ifrange206">http://purl.org/NET/http-errata#ifrange206</a>&gt;)
1279         </li>
1280         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/35">http://tools.ietf.org/wg/httpbis/trac/ticket/35</a>&gt;: "Normative and Informative references"
1281         </li>
1282         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/86">http://tools.ietf.org/wg/httpbis/trac/ticket/86</a>&gt;: "Normative up-to-date references"
1283         </li>
1284      </ul>
1285      <h2 id="rfc.section.D.3"><a href="#rfc.section.D.3">D.3</a>&nbsp;Since draft-ietf-httpbis-p5-range-01
1286      </h2>
1287      <p id="rfc.section.D.3.p.1">Closed issues: </p>
1288      <ul>
1289         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/55">http://tools.ietf.org/wg/httpbis/trac/ticket/55</a>&gt;: "Updating to RFC4288"
1290         </li>
1291      </ul>
1292      <p id="rfc.section.D.3.p.2">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
1293      </p>
1294      <ul>
1295         <li>Add explicit references to BNF syntax and rules imported from other parts of the specification.</li>
1296      </ul>
1297      <h2 id="rfc.section.D.4"><a href="#rfc.section.D.4">D.4</a>&nbsp;<a id="changes.since.02" href="#changes.since.02">Since draft-ietf-httpbis-p5-range-02</a></h2>
1298      <p id="rfc.section.D.4.p.1">Ongoing work on IANA Message Header Field Registration (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/40">http://tools.ietf.org/wg/httpbis/trac/ticket/40</a>&gt;):
1299      </p>
1300      <ul>
1301         <li>Reference RFC 3984, and update header field registrations for headers defined in this document.</li>
1302      </ul>
1303      <h2 id="rfc.section.D.5"><a href="#rfc.section.D.5">D.5</a>&nbsp;<a id="changes.since.03" href="#changes.since.03">Since draft-ietf-httpbis-p5-range-03</a></h2>
1304      <h2 id="rfc.section.D.6"><a href="#rfc.section.D.6">D.6</a>&nbsp;<a id="changes.since.04" href="#changes.since.04">Since draft-ietf-httpbis-p5-range-04</a></h2>
1305      <p id="rfc.section.D.6.p.1">Closed issues: </p>
1306      <ul>
1307         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/133">http://tools.ietf.org/wg/httpbis/trac/ticket/133</a>&gt;: "multipart/byteranges minimum number of parts"
1308         </li>
1309      </ul>
1310      <p id="rfc.section.D.6.p.2">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
1311      </p>
1312      <ul>
1313         <li>Use "/" instead of "|" for alternatives.</li>
1314         <li>Introduce new ABNF rules for "bad" whitespace ("BWS"), optional whitespace ("OWS") and required whitespace ("RWS").</li>
1315         <li>Rewrite ABNFs to spell out whitespace rules, factor out header field value format definitions.</li>
1316      </ul>
1317      <h2 id="rfc.section.D.7"><a href="#rfc.section.D.7">D.7</a>&nbsp;<a id="changes.since.05" href="#changes.since.05">Since draft-ietf-httpbis-p5-range-05</a></h2>
1318      <p id="rfc.section.D.7.p.1">Closed issues: </p>
1319      <ul>
1320         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/142">http://tools.ietf.org/wg/httpbis/trac/ticket/142</a>&gt;: "State base for *-byte-pos and suffix-length"
1321         </li>
1322      </ul>
1323      <p id="rfc.section.D.7.p.2">Ongoing work on Custom Ranges (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/85">http://tools.ietf.org/wg/httpbis/trac/ticket/85</a>&gt;):
1324      </p>
1325      <ul>
1326         <li>Remove bias in favor of byte ranges; allow custom ranges in ABNF.</li>
1327      </ul>
1328      <p id="rfc.section.D.7.p.3">Final work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
1329      </p>
1330      <ul>
1331         <li>Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.</li>
1332      </ul>
1333      <h2 id="rfc.section.D.8"><a href="#rfc.section.D.8">D.8</a>&nbsp;<a id="changes.since.06" href="#changes.since.06">Since draft-ietf-httpbis-p5-range-06</a></h2>
1334      <p id="rfc.section.D.8.p.1">Closed issues: </p>
1335      <ul>
1336         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/161">http://tools.ietf.org/wg/httpbis/trac/ticket/161</a>&gt;: "base for numeric protocol elements"
1337         </li>
1338      </ul>
1339      <h2 id="rfc.section.D.9"><a href="#rfc.section.D.9">D.9</a>&nbsp;<a id="changes.since.07" href="#changes.since.07">Since draft-ietf-httpbis-p5-range-07</a></h2>
1340      <p id="rfc.section.D.9.p.1">Closed issues: </p>
1341      <ul>
1342         <li>Fixed discrepancy in the If-Range definition about allowed validators.</li>
1343         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/150">http://tools.ietf.org/wg/httpbis/trac/ticket/150</a>&gt;: "multipart/byteranges for custom range units"
1344         </li>
1345         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/151">http://tools.ietf.org/wg/httpbis/trac/ticket/151</a>&gt;: "range unit missing from other-ranges-specifier in Range header"
1346         </li>
1347         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/198">http://tools.ietf.org/wg/httpbis/trac/ticket/198</a>&gt;: "move IANA registrations for optional status codes"
1348         </li>
1349      </ul>
1350      <h2 id="rfc.section.D.10"><a href="#rfc.section.D.10">D.10</a>&nbsp;<a id="changes.since.08" href="#changes.since.08">Since draft-ietf-httpbis-p5-range-08</a></h2>
1351      <p id="rfc.section.D.10.p.1">No significant changes.</p>
1352      <h2 id="rfc.section.D.11"><a href="#rfc.section.D.11">D.11</a>&nbsp;<a id="changes.since.09" href="#changes.since.09">Since draft-ietf-httpbis-p5-range-09</a></h2>
1353      <p id="rfc.section.D.11.p.1">No significant changes.</p>
1354      <h2 id="rfc.section.D.12"><a href="#rfc.section.D.12">D.12</a>&nbsp;<a id="changes.since.10" href="#changes.since.10">Since draft-ietf-httpbis-p5-range-10</a></h2>
1355      <p id="rfc.section.D.12.p.1">Closed issues: </p>
1356      <ul>
1357         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/69">http://tools.ietf.org/wg/httpbis/trac/ticket/69</a>&gt;: "Clarify 'Requested Variant'"
1358         </li>
1359         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/109">http://tools.ietf.org/wg/httpbis/trac/ticket/109</a>&gt;: "Clarify entity / representation / variant terminology"
1360         </li>
1361         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/220">http://tools.ietf.org/wg/httpbis/trac/ticket/220</a>&gt;: "consider removing the 'changes from 2068' sections"
1362         </li>
1363      </ul>
1364      <p id="rfc.section.D.12.p.2">Ongoing work on Custom Ranges (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/85">http://tools.ietf.org/wg/httpbis/trac/ticket/85</a>&gt;):
1365      </p>
1366      <ul>
1367         <li>Add IANA registry.</li>
1368      </ul>
1369      <h2 id="rfc.section.D.13"><a href="#rfc.section.D.13">D.13</a>&nbsp;<a id="changes.since.11" href="#changes.since.11">Since draft-ietf-httpbis-p5-range-11</a></h2>
1370      <p id="rfc.section.D.13.p.1">Closed issues: </p>
1371      <ul>
1372         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/217">http://tools.ietf.org/wg/httpbis/trac/ticket/217</a>&gt;: "Caches can't be required to serve ranges"
1373         </li>
1374      </ul>
1375      <h2 id="rfc.section.D.14"><a href="#rfc.section.D.14">D.14</a>&nbsp;<a id="changes.since.12" href="#changes.since.12">Since draft-ietf-httpbis-p5-range-12</a></h2>
1376      <p id="rfc.section.D.14.p.1">None yet.</p>
1377      <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1>
1378      <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> 
1379      </p>
1380      <div class="print2col">
1381         <ul class="ind">
1382            <li><a id="rfc.index.2" href="#rfc.index.2"><b>2</b></a><ul>
1383                  <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.1</a></li>
1384               </ul>
1385            </li>
1386            <li><a id="rfc.index.4" href="#rfc.index.4"><b>4</b></a><ul>
1387                  <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">5.2</a>, <a href="#rfc.xref.status.416.2">6.1</a></li>
1388               </ul>
1389            </li>
1390            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
1391                  <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></li>
1392               </ul>
1393            </li>
1394            <li><a id="rfc.index.C" href="#rfc.index.C"><b>C</b></a><ul>
1395                  <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>
1396               </ul>
1397            </li>
1398            <li><a id="rfc.index.G" href="#rfc.index.G"><b>G</b></a><ul>
1399                  <li><tt>Grammar</tt>&nbsp;&nbsp;
1400                     <ul>
1401                        <li><tt>Accept-Ranges</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.4"><b>5.1</b></a></li>
1402                        <li><tt>Accept-Ranges-v</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>5.1</b></a></li>
1403                        <li><tt>acceptable-ranges</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>5.1</b></a></li>
1404                        <li><tt>byte-content-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>5.2</b></a></li>
1405                        <li><tt>byte-range-resp-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.11"><b>5.2</b></a></li>
1406                        <li><tt>byte-range-set</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.17"><b>5.4.1</b></a></li>
1407                        <li><tt>byte-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.18"><b>5.4.1</b></a></li>
1408                        <li><tt>byte-ranges-specifier</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.16"><b>5.4.1</b></a></li>
1409                        <li><tt>bytes-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.2"><b>2</b></a></li>
1410                        <li><tt>Content-Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>5.2</b></a></li>
1411                        <li><tt>content-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>5.2</b></a></li>
1412                        <li><tt>Content-Range-v</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>5.2</b></a></li>
1413                        <li><tt>first-byte-pos</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.19"><b>5.4.1</b></a></li>
1414                        <li><tt>If-Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.13"><b>5.3</b></a></li>
1415                        <li><tt>If-Range-v</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.14"><b>5.3</b></a></li>
1416                        <li><tt>instance-length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.12"><b>5.2</b></a></li>
1417                        <li><tt>last-byte-pos</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.20"><b>5.4.1</b></a></li>
1418                        <li><tt>other-range-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>2</b></a></li>
1419                        <li><tt>Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.23"><b>5.4.2</b></a></li>
1420                        <li><tt>range-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>2</b></a></li>
1421                        <li><tt>ranges-specifier</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.15"><b>5.4.1</b></a></li>
1422                        <li><tt>suffix-byte-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.21"><b>5.4.1</b></a></li>
1423                        <li><tt>suffix-length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.22"><b>5.4.1</b></a></li>
1424                     </ul>
1425                  </li>
1426               </ul>
1427            </li>
1428            <li><a id="rfc.index.H" href="#rfc.index.H"><b>H</b></a><ul>
1429                  <li>Header Fields&nbsp;&nbsp;
1430                     <ul>
1431                        <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></li>
1432                        <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>
1433                        <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>
1434                        <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>
1435                     </ul>
1436                  </li>
1437               </ul>
1438            </li>
1439            <li><a id="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul>
1440                  <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>
1441               </ul>
1442            </li>
1443            <li><a id="rfc.index.M" href="#rfc.index.M"><b>M</b></a><ul>
1444                  <li>Media Type&nbsp;&nbsp;
1445                     <ul>
1446                        <li>multipart/byteranges&nbsp;&nbsp;<a href="#rfc.iref.m.1"><b>A</b></a></li>
1447                        <li>multipart/x-byteranges&nbsp;&nbsp;<a href="#rfc.iref.m.4">A</a></li>
1448                     </ul>
1449                  </li>
1450                  <li>multipart/byteranges Media Type&nbsp;&nbsp;<a href="#rfc.iref.m.2"><b>A</b></a></li>
1451                  <li>multipart/x-byteranges Media Type&nbsp;&nbsp;<a href="#rfc.iref.m.3">A</a></li>
1452               </ul>
1453            </li>
1454            <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul>
1455                  <li><em>Part1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1.2</a>, <a href="#rfc.xref.Part1.2">1.2.1</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">1.2.2</a>, <a href="#rfc.xref.Part1.6">7</a>, <a href="#Part1"><b>9.1</b></a><ul>
1456                        <li><em>Section 1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">1.2</a></li>
1457                        <li><em>Section 1.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.2">1.2.1</a>, <a href="#rfc.xref.Part1.3">1.2.1</a>, <a href="#rfc.xref.Part1.4">1.2.1</a></li>
1458                        <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.5">1.2.2</a></li>
1459                     </ul>
1460                  </li>
1461                  <li><em>Part4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">1.2.2</a>, <a href="#rfc.xref.Part4.2">4</a>, <a href="#Part4"><b>9.1</b></a><ul>
1462                        <li><em>Section 2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">1.2.2</a></li>
1463                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.2">4</a></li>
1464                     </ul>
1465                  </li>
1466               </ul>
1467            </li>
1468            <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul>
1469                  <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>
1470                  <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>
1471                        <li><em>Section 5.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.1">A</a></li>
1472                     </ul>
1473                  </li>
1474                  <li><em>RFC2119</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2119.1">1.1</a>, <a href="#RFC2119"><b>9.1</b></a></li>
1475                  <li><em>RFC2616</em>&nbsp;&nbsp;<a href="#RFC2616"><b>9.2</b></a>, <a href="#rfc.xref.RFC2616.1">D.1</a></li>
1476                  <li><em>RFC3864</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.1">6.2</a>, <a href="#RFC3864"><b>9.2</b></a></li>
1477                  <li><em>RFC4288</em>&nbsp;&nbsp;<a href="#RFC4288"><b>9.2</b></a>, <a href="#rfc.xref.RFC4288.1">A</a></li>
1478                  <li><em>RFC5226</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">2.1</a>, <a href="#RFC5226"><b>9.2</b></a><ul>
1479                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5226.1">2.1</a></li>
1480                     </ul>
1481                  </li>
1482                  <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>
1483                        <li><em>Appendix B.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5234.2">1.2</a></li>
1484                     </ul>
1485                  </li>
1486               </ul>
1487            </li>
1488            <li><a id="rfc.index.S" href="#rfc.index.S"><b>S</b></a><ul>
1489                  <li>Status Codes&nbsp;&nbsp;
1490                     <ul>
1491                        <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.1</a></li>
1492                        <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">5.2</a>, <a href="#rfc.xref.status.416.2">6.1</a></li>
1493                     </ul>
1494                  </li>
1495               </ul>
1496            </li>
1497         </ul>
1498      </div>
1499   </body>
1500</html>
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