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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.copyright">
382      <link rel="Index" href="#rfc.index">
383      <link rel="Chapter" title="1 Introduction" href="#rfc.section.1">
384      <link rel="Chapter" title="2 Notational Conventions and Generic Grammar" href="#rfc.section.2">
385      <link rel="Chapter" title="3 Range Units" href="#rfc.section.3">
386      <link rel="Chapter" title="4 Status Code Definitions" href="#rfc.section.4">
387      <link rel="Chapter" title="5 Combining Byte Ranges" href="#rfc.section.5">
388      <link rel="Chapter" title="6 Header Field Definitions" href="#rfc.section.6">
389      <link rel="Chapter" title="7 IANA Considerations" href="#rfc.section.7">
390      <link rel="Chapter" title="8 Security Considerations" href="#rfc.section.8">
391      <link rel="Chapter" title="9 Acknowledgments" href="#rfc.section.9">
392      <link rel="Chapter" href="#rfc.section.10" title="10 References">
393      <link rel="Appendix" title="A Internet Media Type multipart/byteranges" href="#rfc.section.A">
394      <link rel="Appendix" title="B Compatibility with Previous Versions" href="#rfc.section.B">
395      <link rel="Appendix" title="C Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.C">
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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-04">
408      <meta name="dct.issued" scheme="ISO8601" content="2008-08-29">
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">Network 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">Day Software</td>
423            </tr>
424            <tr>
425               <td class="left">Obsoletes: <a href="https://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">One Laptop per Child</td>
432            </tr>
433            <tr>
434               <td class="left">Expires: March 2, 2009</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 Systems</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">August 29, 2008</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-04</span></p>
496      <div id="rfc.status">
497         <h1><a href="#rfc.status">Status of this Memo</a></h1>
498         <p>By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she
499            is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section
500            6 of BCP 79.
501         </p>
502         <p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note
503            that other groups may also distribute working documents as Internet-Drafts.
504         </p>
505         <p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other
506            documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work
507            in progress”.
508         </p>
509         <p>The list of current Internet-Drafts can be accessed at <a href="http://www.ietf.org/ietf/1id-abstracts.txt">http://www.ietf.org/ietf/1id-abstracts.txt</a>.
510         </p>
511         <p>The list of Internet-Draft Shadow Directories can be accessed at <a href="http://www.ietf.org/shadow.html">http://www.ietf.org/shadow.html</a>.
512         </p>
513         <p>This Internet-Draft will expire on March 2, 2009.</p>
514      </div>
515      <h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1>
516      <p>The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information
517         systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 5 of the
518         seven-part specification that defines the protocol referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616. Part
519         5 defines range-specific requests and the rules for constructing and combining responses to those requests.
520      </p>
521      <h1 id="rfc.note.1"><a href="#rfc.note.1">Editorial Note (To be removed by RFC Editor)</a></h1>
522      <p>Discussion of this draft should take place on the HTTPBIS working group mailing list (ietf-http-wg@w3.org). The current issues
523         list is at &lt;<a href="http://www.tools.ietf.org/wg/httpbis/trac/report/11">http://www.tools.ietf.org/wg/httpbis/trac/report/11</a>&gt; and related documents (including fancy diffs) can be found at &lt;<a href="http://www.tools.ietf.org/wg/httpbis/">http://www.tools.ietf.org/wg/httpbis/</a>&gt;.
524      </p>
525      <p>The changes in this draft are summarized in <a href="#changes.since.02" title="Since draft-ietf-httpbis-p5-range-02">Appendix&nbsp;C.4</a>.
526      </p>
527      <hr class="noprint">
528      <h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1>
529      <ul class="toc">
530         <li><a href="#rfc.section.1">1.</a>&nbsp;&nbsp;&nbsp;<a href="#introduction">Introduction</a><ul>
531               <li><a href="#rfc.section.1.1">1.1</a>&nbsp;&nbsp;&nbsp;<a href="#intro.requirements">Requirements</a></li>
532            </ul>
533         </li>
534         <li><a href="#rfc.section.2">2.</a>&nbsp;&nbsp;&nbsp;<a href="#notation">Notational Conventions and Generic Grammar</a></li>
535         <li><a href="#rfc.section.3">3.</a>&nbsp;&nbsp;&nbsp;<a href="#range.units">Range Units</a></li>
536         <li><a href="#rfc.section.4">4.</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.4">Status Code Definitions</a><ul>
537               <li><a href="#rfc.section.4.1">4.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.206">206 Partial Content</a></li>
538               <li><a href="#rfc.section.4.2">4.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.416">416 Requested Range Not Satisfiable</a></li>
539            </ul>
540         </li>
541         <li><a href="#rfc.section.5">5.</a>&nbsp;&nbsp;&nbsp;<a href="#combining.byte.ranges">Combining Byte Ranges</a></li>
542         <li><a href="#rfc.section.6">6.</a>&nbsp;&nbsp;&nbsp;<a href="#header.fields">Header Field Definitions</a><ul>
543               <li><a href="#rfc.section.6.1">6.1</a>&nbsp;&nbsp;&nbsp;<a href="#header.accept-ranges">Accept-Ranges</a></li>
544               <li><a href="#rfc.section.6.2">6.2</a>&nbsp;&nbsp;&nbsp;<a href="#header.content-range">Content-Range</a></li>
545               <li><a href="#rfc.section.6.3">6.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.if-range">If-Range</a></li>
546               <li><a href="#rfc.section.6.4">6.4</a>&nbsp;&nbsp;&nbsp;<a href="#header.range">Range</a><ul>
547                     <li><a href="#rfc.section.6.4.1">6.4.1</a>&nbsp;&nbsp;&nbsp;<a href="#byte.ranges">Byte Ranges</a></li>
548                     <li><a href="#rfc.section.6.4.2">6.4.2</a>&nbsp;&nbsp;&nbsp;<a href="#range.retrieval.requests">Range Retrieval Requests</a></li>
549                  </ul>
550               </li>
551            </ul>
552         </li>
553         <li><a href="#rfc.section.7">7.</a>&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
554               <li><a href="#rfc.section.7.1">7.1</a>&nbsp;&nbsp;&nbsp;<a href="#message.header.registration">Message Header Registration</a></li>
555            </ul>
556         </li>
557         <li><a href="#rfc.section.8">8.</a>&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a></li>
558         <li><a href="#rfc.section.9">9.</a>&nbsp;&nbsp;&nbsp;<a href="#ack">Acknowledgments</a></li>
559         <li><a href="#rfc.section.10">10.</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
560               <li><a href="#rfc.section.10.1">10.1</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
561               <li><a href="#rfc.section.10.2">10.2</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
562            </ul>
563         </li>
564         <li><a href="#rfc.section.A">A.</a>&nbsp;&nbsp;&nbsp;<a href="#internet.media.type.multipart.byteranges">Internet Media Type multipart/byteranges</a></li>
565         <li><a href="#rfc.section.B">B.</a>&nbsp;&nbsp;&nbsp;<a href="#compatibility">Compatibility with Previous Versions</a><ul>
566               <li><a href="#rfc.section.B.1">B.1</a>&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2068">Changes from RFC 2068</a></li>
567               <li><a href="#rfc.section.B.2">B.2</a>&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616">Changes from RFC 2616</a></li>
568            </ul>
569         </li>
570         <li><a href="#rfc.section.C">C.</a>&nbsp;&nbsp;&nbsp;<a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul>
571               <li><a href="#rfc.section.C.1">C.1</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.1">Since RFC2616</a></li>
572               <li><a href="#rfc.section.C.2">C.2</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.2">Since draft-ietf-httpbis-p5-range-00</a></li>
573               <li><a href="#rfc.section.C.3">C.3</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.3">Since draft-ietf-httpbis-p5-range-01</a></li>
574               <li><a href="#rfc.section.C.4">C.4</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.02">Since draft-ietf-httpbis-p5-range-02</a></li>
575               <li><a href="#rfc.section.C.5">C.5</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.03">Since draft-ietf-httpbis-p5-range-03</a></li>
576            </ul>
577         </li>
578         <li><a href="#rfc.index">Index</a></li>
579         <li><a href="#rfc.authors">Authors' Addresses</a></li>
580         <li><a href="#rfc.ipr">Intellectual Property and Copyright Statements</a></li>
581      </ul>
582      <div id="introduction">
583         <h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a>&nbsp;<a href="#introduction">Introduction</a></h1>
584         <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
585            has stored a partial representation, it is desirable to request the remainder of that representation in a subsequent request
586            rather than transfer the entire representation. There are also a number of Web applications that benefit from being able to
587            request only a subset of a larger representation, such as a single page of a very large document or only part of an image
588            to be rendered by a device with limited local storage.
589         </p>
590         <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
591            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
592            request without impacting interoperability. Partial responses are indicated by a distinct status code to not be mistaken for
593            full responses by intermediate caches that might not implement the feature.
594         </p>
595         <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
596            requests for byte ranges.
597         </p>
598         <div id="intro.requirements">
599            <h2 id="rfc.section.1.1"><a href="#rfc.section.1.1">1.1</a>&nbsp;<a href="#intro.requirements">Requirements</a></h2>
600            <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"
601               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>.
602            </p>
603            <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level requirements for the protocols it implements. An implementation that satisfies all the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level and all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "unconditionally compliant"; one that satisfies all the <em class="bcp14">MUST</em> level requirements but not all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "conditionally compliant."
604            </p>
605         </div>
606      </div>
607      <div id="notation">
608         <h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a href="#notation">Notational Conventions and Generic Grammar</a></h1>
609         <p id="rfc.section.2.p.1">This specification uses the ABNF syntax defined in <a href="p1-messaging.html#notation.abnf" title="Augmented BNF">Section 2.1</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> and the core rules defined in <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 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>: <span class="comment" id="abnf.dep">[<a href="#abnf.dep" class="smpl">abnf.dep</a>: ABNF syntax and basic rules will be adopted from RFC 5234, see &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;.]</span> 
610         </p>
611         <div id="rfc.figure.u.1"></div><pre class="inline">  <a href="#notation" class="smpl">DIGIT</a>      = &lt;DIGIT, 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 2.2</a>&gt;
612  <a href="#notation" class="smpl">SP</a>         = &lt;SP, 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 2.2</a>&gt;
613</pre><div id="rfc.figure.u.2"></div><pre class="inline">  <a href="#notation" class="smpl">token</a>      = &lt;token, 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#basic.rules" title="Basic Rules">Section 2.2</a>&gt;
614</pre><div id="abnf.dependencies">
615            <p id="rfc.section.2.p.4">  The ABNF rules below are defined in other parts:</p>
616         </div>
617         <div id="rfc.figure.u.3"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">HTTP-date</a>  = &lt;HTTP-date, defined in <a href="#Part1" id="rfc.xref.Part1.6"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#full.date" title="Full Date">Section 3.3.1</a>&gt;
618</pre><div id="rfc.figure.u.4"></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 3</a>&gt;
619</pre></div>
620      <div id="range.units">
621         <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a>&nbsp;<a href="#range.units">Range Units</a></h1>
622         <p id="rfc.section.3.p.1">HTTP/1.1 allows a client to request that only part (a range of) the response entity be included within the response. HTTP/1.1
623            uses range units in the Range (<a href="#header.range" id="rfc.xref.header.range.1" title="Range">Section&nbsp;6.4</a>) and Content-Range (<a href="#header.content-range" id="rfc.xref.header.content-range.1" title="Content-Range">Section&nbsp;6.2</a>) header fields. An entity can be broken down into subranges according to various structural units.
624         </p>
625         <div id="rfc.figure.u.5"></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>
626  <a href="#range.units" class="smpl">bytes-unit</a>       = "bytes"
627  <a href="#range.units" class="smpl">other-range-unit</a> = <a href="#notation" class="smpl">token</a>
628</pre><p id="rfc.section.3.p.3">The only range unit defined by HTTP/1.1 is "bytes". HTTP/1.1 implementations <em class="bcp14">MAY</em> ignore ranges specified using other units.
629         </p>
630         <p id="rfc.section.3.p.4">HTTP/1.1 has been designed to allow implementations of applications that do not depend on knowledge of ranges.</p>
631      </div>
632      <div>
633         <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;Status Code Definitions
634         </h1>
635         <div id="status.206">
636            <div id="rfc.iref.2.1"></div>
637            <div id="rfc.iref.s.1"></div>
638            <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a href="#status.206">206 Partial Content</a></h2>
639            <p id="rfc.section.4.1.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.2" title="Range">Section&nbsp;6.4</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;6.3</a>) to make the request conditional.
640            </p>
641            <p id="rfc.section.4.1.p.2">The response <em class="bcp14">MUST</em> include the following header fields:
642            </p>
643            <ul>
644               <li>Either a Content-Range header field (<a href="#header.content-range" id="rfc.xref.header.content-range.2" title="Content-Range">Section&nbsp;6.2</a>) indicating the range included with this response, or a multipart/byteranges Content-Type including Content-Range fields
645                  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.
646               </li>
647               <li>Date</li>
648               <li>ETag and/or Content-Location, if the header would have been sent in a 200 response to the same request</li>
649               <li>Expires, Cache-Control, and/or Vary, if the field-value might differ from that sent in any previous response for the same
650                  variant
651               </li>
652            </ul>
653            <p id="rfc.section.4.1.p.3">If the 206 response is the result of an If-Range request, the response <em class="bcp14">SHOULD NOT</em> include other entity-headers. Otherwise, the response <em class="bcp14">MUST</em> include all of the entity-headers that would have been returned with a 200 (OK) response to the same request.
654            </p>
655            <p id="rfc.section.4.1.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 headers do not match exactly, see <a href="#combining.byte.ranges" title="Combining Byte Ranges">Section&nbsp;5</a>.
656            </p>
657            <p id="rfc.section.4.1.p.5">A cache that does not support the Range and Content-Range headers <em class="bcp14">MUST NOT</em> cache 206 (Partial Content) responses.
658            </p>
659         </div>
660         <div id="status.416">
661            <div id="rfc.iref.4.1"></div>
662            <div id="rfc.iref.s.2"></div>
663            <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a>&nbsp;<a href="#status.416">416 Requested Range Not Satisfiable</a></h2>
664            <p id="rfc.section.4.2.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.3" title="Range">Section&nbsp;6.4</a>), and none of the range-specifier values in this field overlap the current extent of the selected resource, and the request
665               did not include an If-Range request-header field. (For byte-ranges, this means that the first-byte-pos of all of the byte-range-spec
666               values were greater than the current length of the selected resource.)
667            </p>
668            <p id="rfc.section.4.2.p.2">When this status code is returned for a byte-range request, the response <em class="bcp14">SHOULD</em> include a Content-Range entity-header field specifying the current length of the selected resource (see <a href="#header.content-range" id="rfc.xref.header.content-range.3" title="Content-Range">Section&nbsp;6.2</a>). This response <em class="bcp14">MUST NOT</em> use the multipart/byteranges content-type.
669            </p>
670         </div>
671      </div>
672      <div id="combining.byte.ranges">
673         <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a href="#combining.byte.ranges">Combining Byte Ranges</a></h1>
674         <p id="rfc.section.5.p.1">A response might transfer only a subrange of the bytes of an entity-body, either because the request included one or more
675            Range specifications, or because a connection was broken prematurely. After several such transfers, a cache might have received
676            several ranges of the same entity-body.
677         </p>
678         <p id="rfc.section.5.p.2">If a cache has a stored non-empty set of subranges for an entity, and an incoming response transfers another subrange, the
679            cache <em class="bcp14">MAY</em> combine the new subrange with the existing set if both the following conditions are met:
680         </p>
681         <ul>
682            <li>Both the incoming response and the cache entry have a cache validator.</li>
683            <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 5</a> of <a href="#Part4" id="rfc.xref.Part4.2"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>).
684            </li>
685         </ul>
686         <p id="rfc.section.5.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
687            response if these values are equal or missing), and <em class="bcp14">MUST</em> discard the other partial information.
688         </p>
689      </div>
690      <div id="header.fields">
691         <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a href="#header.fields">Header Field Definitions</a></h1>
692         <p id="rfc.section.6.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to range requests and partial responses.</p>
693         <p id="rfc.section.6.p.2">For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who
694            receives the entity.
695         </p>
696         <div id="header.accept-ranges">
697            <div id="rfc.iref.a.1"></div>
698            <div id="rfc.iref.h.1"></div>
699            <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a href="#header.accept-ranges">Accept-Ranges</a></h2>
700            <p id="rfc.section.6.1.p.1">The Accept-Ranges response-header field allows the server to indicate its acceptance of range requests for a resource:</p>
701            <div id="rfc.figure.u.6"></div><pre class="inline"><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span>  <a href="#header.accept-ranges" class="smpl">Accept-Ranges</a>     = "Accept-Ranges" ":" <a href="#header.accept-ranges" class="smpl">acceptable-ranges</a>
702  <a href="#header.accept-ranges" class="smpl">acceptable-ranges</a> = 1#<a href="#range.units" class="smpl">range-unit</a> | "none"
703</pre><p id="rfc.section.6.1.p.3">Origin servers that accept byte-range requests <em class="bcp14">MAY</em> send
704            </p>
705            <div id="rfc.figure.u.7"></div><pre class="text">       Accept-Ranges: bytes
706</pre><p id="rfc.section.6.1.p.5">but are not required to do so. Clients <em class="bcp14">MAY</em> generate byte-range requests without having received this header for the resource involved. Range units are defined in <a href="#range.units" title="Range Units">Section&nbsp;3</a>.
707            </p>
708            <p id="rfc.section.6.1.p.6">Servers that do not accept any kind of range request for a resource <em class="bcp14">MAY</em> send
709            </p>
710            <div id="rfc.figure.u.8"></div><pre class="text">       Accept-Ranges: none
711</pre><p id="rfc.section.6.1.p.8">to advise the client not to attempt a range request.</p>
712         </div>
713         <div id="header.content-range">
714            <div id="rfc.iref.c.1"></div>
715            <div id="rfc.iref.h.2"></div>
716            <h2 id="rfc.section.6.2"><a href="#rfc.section.6.2">6.2</a>&nbsp;<a href="#header.content-range">Content-Range</a></h2>
717            <p id="rfc.section.6.2.p.1">The Content-Range entity-header is sent with a partial entity-body to specify where in the full entity-body the partial body
718               should be applied. Range units are defined in <a href="#range.units" title="Range Units">Section&nbsp;3</a>.
719            </p>
720            <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.6"></span><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span>  <a href="#header.content-range" class="smpl">Content-Range</a> = "Content-Range" ":" <a href="#header.content-range" class="smpl">content-range-spec</a>
721 
722  <a href="#header.content-range" class="smpl">content-range-spec</a>      = <a href="#header.content-range" class="smpl">byte-content-range-spec</a>
723  <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>
724                            <a href="#header.content-range" class="smpl">byte-range-resp-spec</a> "/"
725                            ( <a href="#header.content-range" class="smpl">instance-length</a> | "*" )
726 
727  <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>)
728                          | "*"
729                         
730  <a href="#header.content-range" class="smpl">instance-length</a>         = 1*<a href="#notation" class="smpl">DIGIT</a>
731</pre><p id="rfc.section.6.2.p.3">The header <em class="bcp14">SHOULD</em> indicate the total length of the full entity-body, unless this length is unknown or difficult to determine. The asterisk "*"
732               character means that the instance-length is unknown at the time when the response was generated.
733            </p>
734            <p id="rfc.section.6.2.p.4">Unlike byte-ranges-specifier values (see <a href="#byte.ranges" title="Byte Ranges">Section&nbsp;6.4.1</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.
735            </p>
736            <p id="rfc.section.6.2.p.5">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
737               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.
738            </p>
739            <p id="rfc.section.6.2.p.6">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
740               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 "*".
741            </p>
742            <p id="rfc.section.6.2.p.7">Examples of byte-content-range-spec values, assuming that the entity contains a total of 1234 bytes: </p>
743            <ul>
744               <li>The first 500 bytes: <span id="rfc.figure.u.10"></span><pre class="text">   bytes 0-499/1234
745</pre> </li>
746               <li>The second 500 bytes: <span id="rfc.figure.u.11"></span><pre class="text">   bytes 500-999/1234
747</pre> </li>
748               <li>All except for the first 500 bytes: <span id="rfc.figure.u.12"></span><pre class="text">   bytes 500-1233/1234
749</pre> </li>
750               <li>The last 500 bytes: <span id="rfc.figure.u.13"></span><pre class="text">   bytes 734-1233/1234
751</pre> </li>
752            </ul>
753            <p id="rfc.section.6.2.p.8">When an HTTP message includes the content of a single range (for example, a response to a request for a single range, or to
754               a request for a set of ranges that overlap without any holes), this content is transmitted with a Content-Range header, and
755               a Content-Length header showing the number of bytes actually transferred. For example,
756            </p>
757            <div id="rfc.figure.u.14"></div><pre class="text">    HTTP/1.1 206 Partial Content
758    Date: Wed, 15 Nov 1995 06:25:24 GMT
759    Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
760    Content-Range: bytes 21010-47021/47022
761    Content-Length: 26012
762    Content-Type: image/gif
763</pre><p id="rfc.section.6.2.p.10">When an HTTP message includes the content of multiple ranges (for example, a response to a request for multiple non-overlapping
764               ranges), these are transmitted as a multipart message. The multipart media type used for this purpose is "multipart/byteranges"
765               as defined in <a href="#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix&nbsp;A</a>. See <a href="#changes.from.rfc.2068" title="Changes from RFC 2068">Appendix&nbsp;B.1</a> for a compatibility issue.
766            </p>
767            <p id="rfc.section.6.2.p.11">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 byte-ranges in a single request.
768            </p>
769            <p id="rfc.section.6.2.p.12">When a client requests multiple byte-ranges in one request, the server <em class="bcp14">SHOULD</em> return them in the order that they appeared in the request.
770            </p>
771            <p id="rfc.section.6.2.p.13">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
772               the full entity).
773            </p>
774            <p id="rfc.section.6.2.p.14">If the server receives a request (other than one including an If-Range request-header field) with an unsatisfiable Range request-header
775               field (that is, all of whose byte-range-spec values have a first-byte-pos value greater than the current length of the selected
776               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;4.2</a>).
777            </p>
778            <ul class="empty">
779               <li><b>Note:</b> clients cannot depend on servers to send a 416 (Requested range not satisfiable) response instead of a 200 (OK) response for
780                  an unsatisfiable Range request-header, since not all servers implement this request-header.
781               </li>
782            </ul>
783         </div>
784         <div id="header.if-range">
785            <div id="rfc.iref.i.1"></div>
786            <div id="rfc.iref.h.3"></div>
787            <h2 id="rfc.section.6.3"><a href="#rfc.section.6.3">6.3</a>&nbsp;<a href="#header.if-range">If-Range</a></h2>
788            <p id="rfc.section.6.3.p.1">If a client has a partial copy of an entity in its cache, and wishes to have an up-to-date copy of the entire entity in its
789               cache, it could use the Range request-header with a conditional GET (using either or both of If-Unmodified-Since and If-Match.)
790               However, if the condition fails because the entity has been modified, the client would then have to make a second request
791               to obtain the entire current entity-body.
792            </p>
793            <p id="rfc.section.6.3.p.2">The If-Range header allows a client to "short-circuit" the second request. Informally, its meaning is `if the entity is unchanged,
794               send me the part(s) that I am missing; otherwise, send me the entire new entity'.
795            </p>
796            <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.11"></span>  <a href="#header.if-range" class="smpl">If-Range</a> = "If-Range" ":" ( <a href="#abnf.dependencies" class="smpl">entity-tag</a> | <a href="#abnf.dependencies" class="smpl">HTTP-date</a> )
797</pre><p id="rfc.section.6.3.p.4">If the client has no entity tag for an entity, but does have a Last-Modified date, it <em class="bcp14">MAY</em> use that date in an If-Range header. (The server can distinguish between a valid HTTP-date and any form of entity-tag by examining
798               no more than two characters.) The If-Range header <em class="bcp14">SHOULD</em> only be used together with a Range header, and <em class="bcp14">MUST</em> be ignored if the request does not include a Range header, or if the server does not support the sub-range operation.
799            </p>
800            <p id="rfc.section.6.3.p.5">If the entity tag given in the If-Range header matches the current entity tag for the entity, then the server <em class="bcp14">SHOULD</em> provide the specified sub-range of the entity using a 206 (Partial Content) response. If the entity tag does not match, then
801               the server <em class="bcp14">SHOULD</em> return the entire entity using a 200 (OK) response.
802            </p>
803         </div>
804         <div id="header.range">
805            <div id="rfc.iref.r.1"></div>
806            <div id="rfc.iref.h.4"></div>
807            <h2 id="rfc.section.6.4"><a href="#rfc.section.6.4">6.4</a>&nbsp;<a href="#header.range">Range</a></h2>
808            <div id="byte.ranges">
809               <h3 id="rfc.section.6.4.1"><a href="#rfc.section.6.4.1">6.4.1</a>&nbsp;<a href="#byte.ranges">Byte Ranges</a></h3>
810               <p id="rfc.section.6.4.1.p.1">Since all HTTP entities are represented in HTTP messages as sequences of bytes, the concept of a byte range is meaningful
811                  for any HTTP entity. (However, not all clients and servers need to support byte-range operations.)
812               </p>
813               <p id="rfc.section.6.4.1.p.2">Byte range specifications in HTTP apply to the sequence of bytes in the entity-body (not necessarily the same as the message-body).</p>
814               <div id="rule.ranges-specifier">
815                  <p id="rfc.section.6.4.1.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 entity.
816                  </p>
817               </div>
818               <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.12"></span><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span><span id="rfc.iref.g.15"></span><span id="rfc.iref.g.16"></span><span id="rfc.iref.g.17"></span>  <a href="#rule.ranges-specifier" class="smpl">ranges-specifier</a> = <a href="#rule.ranges-specifier" class="smpl">byte-ranges-specifier</a>
819  <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>
820  <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> )
821  <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>]
822  <a href="#rule.ranges-specifier" class="smpl">first-byte-pos</a>  = 1*<a href="#notation" class="smpl">DIGIT</a>
823  <a href="#rule.ranges-specifier" class="smpl">last-byte-pos</a>   = 1*<a href="#notation" class="smpl">DIGIT</a>
824</pre><p id="rfc.section.6.4.1.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
825                  gives the byte-offset of the last byte in the range; that is, the byte positions specified are inclusive. Byte offsets start
826                  at zero.
827               </p>
828               <p id="rfc.section.6.4.1.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
829                  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.
830               </p>
831               <p id="rfc.section.6.4.1.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 entity-body, last-byte-pos
832                  is taken to be equal to one less than the current length of the entity-body in bytes.
833               </p>
834               <p id="rfc.section.6.4.1.p.8">By its choice of last-byte-pos, a client can limit the number of bytes retrieved without knowing the size of the entity.</p>
835               <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.18"></span><span id="rfc.iref.g.19"></span>  <a href="#rule.ranges-specifier" class="smpl">suffix-byte-range-spec</a> = "-" <a href="#rule.ranges-specifier" class="smpl">suffix-length</a>
836  <a href="#rule.ranges-specifier" class="smpl">suffix-length</a> = 1*<a href="#notation" class="smpl">DIGIT</a>
837</pre><p id="rfc.section.6.4.1.p.10">A suffix-byte-range-spec is used to specify the suffix of the entity-body, of a length given by the suffix-length value. (That
838                  is, this form specifies the last N bytes of an entity-body.) If the entity is shorter than the specified suffix-length, the
839                  entire entity-body is used.
840               </p>
841               <p id="rfc.section.6.4.1.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
842                  length of the entity-body, or at least one suffix-byte-range-spec with a non-zero suffix-length, then the byte-range-set is
843                  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 status of 416 (Requested range not satisfiable). Otherwise, the server <em class="bcp14">SHOULD</em> return a response with a status of 206 (Partial Content) containing the satisfiable ranges of the entity-body.
844               </p>
845               <p id="rfc.section.6.4.1.p.12">Examples of byte-ranges-specifier values (assuming an entity-body of length 10000): </p>
846               <ul>
847                  <li>The first 500 bytes (byte offsets 0-499, inclusive): bytes=0-499</li>
848                  <li>The second 500 bytes (byte offsets 500-999, inclusive): bytes=500-999</li>
849                  <li>The final 500 bytes (byte offsets 9500-9999, inclusive): bytes=-500</li>
850                  <li>Or bytes=9500-</li>
851                  <li>The first and last bytes only (bytes 0 and 9999): bytes=0-0,-1</li>
852                  <li>Several legal but not canonical specifications of the second 500 bytes (byte offsets 500-999, inclusive): <br> bytes=500-600,601-999<br> bytes=500-700,601-999
853                  </li>
854               </ul>
855            </div>
856            <div id="range.retrieval.requests">
857               <h3 id="rfc.section.6.4.2"><a href="#rfc.section.6.4.2">6.4.2</a>&nbsp;<a href="#range.retrieval.requests">Range Retrieval Requests</a></h3>
858               <p id="rfc.section.6.4.2.p.1">HTTP retrieval requests using conditional or unconditional GET methods <em class="bcp14">MAY</em> request one or more sub-ranges of the entity, instead of the entire entity, using the Range request header, which applies
859                  to the entity returned as the result of the request:
860               </p>
861               <div id="rfc.figure.u.18"></div><pre class="inline"><span id="rfc.iref.g.20"></span>  <a href="#range.retrieval.requests" class="smpl">Range</a> = "Range" ":" <a href="#rule.ranges-specifier" class="smpl">ranges-specifier</a>
862</pre><p id="rfc.section.6.4.2.p.3">A server <em class="bcp14">MAY</em> ignore the Range header. However, HTTP/1.1 origin servers and intermediate caches ought to support byte ranges when possible,
863                  since Range supports efficient recovery from partially failed transfers, and supports efficient partial retrieval of large
864                  entities.
865               </p>
866               <p id="rfc.section.6.4.2.p.4">If the server supports the Range header and the specified range or ranges are appropriate for the entity: </p>
867               <ul>
868                  <li>The presence of a Range header in an unconditional GET modifies what is returned if the GET is otherwise successful. In other
869                     words, the response carries a status code of 206 (Partial Content) instead of 200 (OK).
870                  </li>
871                  <li>The presence of a Range header in a conditional GET (a request using one or both of If-Modified-Since and If-None-Match, or
872                     one or both of If-Unmodified-Since and If-Match) modifies what is returned if the GET is otherwise successful and the condition
873                     is true. It does not affect the 304 (Not Modified) response returned if the conditional is false.
874                  </li>
875               </ul>
876               <p id="rfc.section.6.4.2.p.5">In some cases, it might be more appropriate to use the If-Range header (see <a href="#header.if-range" id="rfc.xref.header.if-range.2" title="If-Range">Section&nbsp;6.3</a>) in addition to the Range header.
877               </p>
878               <p id="rfc.section.6.4.2.p.6">If a proxy that supports ranges receives a Range request, forwards the request to an inbound server, and receives an entire
879                  entity in reply, it <em class="bcp14">SHOULD</em> only return the requested range to its client. It <em class="bcp14">SHOULD</em> store the entire received response in its cache if that is consistent with its cache allocation policies.
880               </p>
881            </div>
882         </div>
883      </div>
884      <div id="IANA.considerations">
885         <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a href="#IANA.considerations">IANA Considerations</a></h1>
886         <div id="message.header.registration">
887            <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a href="#message.header.registration">Message Header Registration</a></h2>
888            <p id="rfc.section.7.1.p.1">The Message Header Registry located at &lt;<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>&gt; should be updated with the permanent registrations below (see <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>):
889            </p>
890            <div id="rfc.table.1">
891               <div id="iana.header.registration.table"></div>
892               <table class="tt full left" cellpadding="3" cellspacing="0">
893                  <thead>
894                     <tr>
895                        <th>Header Field Name</th>
896                        <th>Protocol</th>
897                        <th>Status</th>
898                        <th>Reference</th>
899                     </tr>
900                  </thead>
901                  <tbody>
902                     <tr>
903                        <td class="left">Accept-Ranges</td>
904                        <td class="left">http</td>
905                        <td class="left">standard</td>
906                        <td class="left"><a href="#header.accept-ranges" id="rfc.xref.header.accept-ranges.1" title="Accept-Ranges">Section&nbsp;6.1</a> 
907                        </td>
908                     </tr>
909                     <tr>
910                        <td class="left">Content-Range</td>
911                        <td class="left">http</td>
912                        <td class="left">standard</td>
913                        <td class="left"><a href="#header.content-range" id="rfc.xref.header.content-range.4" title="Content-Range">Section&nbsp;6.2</a> 
914                        </td>
915                     </tr>
916                     <tr>
917                        <td class="left">If-Range</td>
918                        <td class="left">http</td>
919                        <td class="left">standard</td>
920                        <td class="left"><a href="#header.if-range" id="rfc.xref.header.if-range.3" title="If-Range">Section&nbsp;6.3</a> 
921                        </td>
922                     </tr>
923                     <tr>
924                        <td class="left">Range</td>
925                        <td class="left">http</td>
926                        <td class="left">standard</td>
927                        <td class="left"><a href="#header.range" id="rfc.xref.header.range.4" title="Range">Section&nbsp;6.4</a> 
928                        </td>
929                     </tr>
930                  </tbody>
931               </table>
932            </div>
933            <p id="rfc.section.7.1.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>
934         </div>
935      </div>
936      <div id="security.considerations">
937         <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a href="#security.considerations">Security Considerations</a></h1>
938         <p id="rfc.section.8.p.1">No additional security considerations have been identified beyond those applicable to HTTP in general <a href="#Part1" id="rfc.xref.Part1.7"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>.
939         </p>
940      </div>
941      <div id="ack">
942         <h1 id="rfc.section.9"><a href="#rfc.section.9">9.</a>&nbsp;<a href="#ack">Acknowledgments</a></h1>
943         <p id="rfc.section.9.p.1">Most of the specification of ranges is based on work originally done by Ari Luotonen and John Franks, with additional input
944            from Steve Zilles, Daniel W. Connolly, Roy T. Fielding, Jim Gettys, Martin Hamilton, Koen Holtman, Shel Kaplan, Paul Leach,
945            Alex Lopez-Ortiz, Larry Masinter, Jeff Mogul, Lou Montulli, David W. Morris, Luigi Rizzo, and Bill Weihl.
946         </p>
947      </div>
948      <h1 id="rfc.references"><a id="rfc.section.10" href="#rfc.section.10">10.</a> References
949      </h1>
950      <h2 id="rfc.references.1"><a href="#rfc.section.10.1" id="rfc.section.10.1">10.1</a> Normative References
951      </h2>
952      <table>
953         <tr>
954            <td class="reference"><b id="Part1">[Part1]</b></td>
955            <td class="top"><a href="mailto:fielding@gbiv.com" title="Day Software">Fielding, R., Ed.</a>, <a href="mailto:jg@laptop.org" title="One Laptop per Child">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="https://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-04">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p1-messaging-04 (work in progress), August&nbsp;2008.
956            </td>
957         </tr>
958         <tr>
959            <td class="reference"><b id="Part3">[Part3]</b></td>
960            <td class="top"><a href="mailto:fielding@gbiv.com" title="Day Software">Fielding, R., Ed.</a>, <a href="mailto:jg@laptop.org" title="One Laptop per Child">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="https://tools.ietf.org/html/draft-ietf-httpbis-p3-payload-04">HTTP/1.1, part 3: Message Payload and Content Negotiation</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p3-payload-04 (work in progress), August&nbsp;2008.
961            </td>
962         </tr>
963         <tr>
964            <td class="reference"><b id="Part4">[Part4]</b></td>
965            <td class="top"><a href="mailto:fielding@gbiv.com" title="Day Software">Fielding, R., Ed.</a>, <a href="mailto:jg@laptop.org" title="One Laptop per Child">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="https://tools.ietf.org/html/draft-ietf-httpbis-p4-conditional-04">HTTP/1.1, part 4: Conditional Requests</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p4-conditional-04 (work in progress), August&nbsp;2008.
966            </td>
967         </tr>
968         <tr>
969            <td class="reference"><b id="Part6">[Part6]</b></td>
970            <td class="top"><a href="mailto:fielding@gbiv.com" title="Day Software">Fielding, R., Ed.</a>, <a href="mailto:jg@laptop.org" title="One Laptop per Child">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="https://tools.ietf.org/html/draft-ietf-httpbis-p6-cache-04">HTTP/1.1, part 6: Caching</a>”, Internet-Draft&nbsp;draft-ietf-httpbis-p6-cache-04 (work in progress), August&nbsp;2008.
971            </td>
972         </tr>
973         <tr>
974            <td class="reference"><b id="RFC2046">[RFC2046]</b></td>
975            <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="https://tools.ietf.org/html/rfc2046">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</a>”, RFC&nbsp;2046, November&nbsp;1996.
976            </td>
977         </tr>
978         <tr>
979            <td class="reference"><b id="RFC2119">[RFC2119]</b></td>
980            <td class="top"><a href="mailto:sob@harvard.edu" title="Harvard University">Bradner, S.</a>, “<a href="https://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.
981            </td>
982         </tr>
983      </table>
984      <h2 id="rfc.references.2"><a href="#rfc.section.10.2" id="rfc.section.10.2">10.2</a> Informative References
985      </h2>
986      <table>
987         <tr>
988            <td class="reference"><b id="RFC2616">[RFC2616]</b></td>
989            <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="https://tools.ietf.org/html/rfc2616">Hypertext Transfer Protocol -- HTTP/1.1</a>”, RFC&nbsp;2616, June&nbsp;1999.
990            </td>
991         </tr>
992         <tr>
993            <td class="reference"><b id="RFC3864">[RFC3864]</b></td>
994            <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="https://tools.ietf.org/html/rfc3864">Registration Procedures for Message Header Fields</a>”, BCP&nbsp;90, RFC&nbsp;3864, September&nbsp;2004.
995            </td>
996         </tr>
997         <tr>
998            <td class="reference"><b id="RFC4288">[RFC4288]</b></td>
999            <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="https://tools.ietf.org/html/rfc4288">Media Type Specifications and Registration Procedures</a>”, BCP&nbsp;13, RFC&nbsp;4288, December&nbsp;2005.
1000            </td>
1001         </tr>
1002      </table>
1003      <div id="internet.media.type.multipart.byteranges">
1004         <div id="rfc.iref.m.1"></div>
1005         <div id="rfc.iref.m.2"></div>
1006         <h1 id="rfc.section.A" class="np"><a href="#rfc.section.A">A.</a>&nbsp;<a href="#internet.media.type.multipart.byteranges">Internet Media Type multipart/byteranges</a></h1>
1007         <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
1008            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>. 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>.
1009         </p>
1010         <p id="rfc.section.A.p.2">The multipart/byteranges media type includes two or more parts, each with its own Content-Type and Content-Range fields. The
1011            required boundary parameter specifies the boundary string used to separate each body-part.
1012         </p>
1013         <p id="rfc.section.A.p.3"></p>
1014         <dl>
1015            <dt>Type name:</dt>
1016            <dd>multipart</dd>
1017            <dt>Subtype name:</dt>
1018            <dd>byteranges</dd>
1019            <dt>Required parameters:</dt>
1020            <dd>boundary</dd>
1021            <dt>Optional parameters:</dt>
1022            <dd>none</dd>
1023            <dt>Encoding considerations:</dt>
1024            <dd>only "7bit", "8bit", or "binary" are permitted</dd>
1025            <dt>Security considerations:</dt>
1026            <dd>none</dd>
1027            <dt>Interoperability considerations:</dt>
1028            <dd>none</dd>
1029            <dt>Published specification:</dt>
1030            <dd>This specification (see <a href="#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix&nbsp;A</a>).
1031            </dd>
1032            <dt>Applications that use this media type:</dt>
1033            <dt>Additional information:</dt>
1034            <dd>
1035               <dl>
1036                  <dt>Magic number(s):</dt>
1037                  <dd>none</dd>
1038                  <dt>File extension(s):</dt>
1039                  <dd>none</dd>
1040                  <dt>Macintosh file type code(s):</dt>
1041                  <dd>none</dd>
1042               </dl> 
1043            </dd>
1044            <dt>Person and email address to contact for further information:</dt>
1045            <dd>See Authors Section.</dd>
1046            <dt>Intended usage:</dt>
1047            <dd>COMMON</dd>
1048            <dt>Restrictions on usage:</dt>
1049            <dd>none</dd>
1050            <dt>Author/Change controller:</dt>
1051            <dd>IESG</dd>
1052         </dl>
1053         <div id="rfc.figure.u.19"></div>
1054         <p>For example:</p><pre class="text">   HTTP/1.1 206 Partial Content
1055   Date: Wed, 15 Nov 1995 06:25:24 GMT
1056   Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1057   Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1058
1059   --THIS_STRING_SEPARATES
1060   Content-type: application/pdf
1061   Content-range: bytes 500-999/8000
1062
1063   ...the first range...
1064   --THIS_STRING_SEPARATES
1065   Content-type: application/pdf
1066   Content-range: bytes 7000-7999/8000
1067
1068   ...the second range
1069   --THIS_STRING_SEPARATES--
1070</pre><p id="rfc.section.A.p.5">Notes: </p>
1071         <ol>
1072            <li>Additional CRLFs may precede the first boundary string in the entity.</li>
1073            <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.
1074            </li>
1075            <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.
1076            </li>
1077         </ol>
1078      </div>
1079      <div id="compatibility">
1080         <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a>&nbsp;<a href="#compatibility">Compatibility with Previous Versions</a></h1>
1081         <div id="changes.from.rfc.2068">
1082            <h2 id="rfc.section.B.1"><a href="#rfc.section.B.1">B.1</a>&nbsp;<a href="#changes.from.rfc.2068">Changes from RFC 2068</a></h2>
1083            <p id="rfc.section.B.1.p.1">Transfer-coding and message lengths all interact in ways that required fixing exactly when chunked encoding is used (to allow
1084               for transfer encoding that may not be self delimiting); it was important to straighten out exactly how message lengths are
1085               computed. (<a href="#header.content-range" id="rfc.xref.header.content-range.5" title="Content-Range">Section&nbsp;6.2</a>, see also <a href="#Part1" id="rfc.xref.Part1.8"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="#Part3" id="rfc.xref.Part3.1"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a> and <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>)
1086            </p>
1087            <p id="rfc.section.B.1.p.2">There are situations where a server (especially a proxy) does not know the full length of a response but is capable of serving
1088               a byterange request. We therefore need a mechanism to allow byteranges with a content-range not indicating the full length
1089               of the message. (<a href="#header.content-range" id="rfc.xref.header.content-range.6" title="Content-Range">Section&nbsp;6.2</a>)
1090            </p>
1091            <p id="rfc.section.B.1.p.3">Range request responses would become very verbose if all meta-data were always returned; by allowing the server to only send
1092               needed headers in a 206 response, this problem can be avoided. (Section <a href="#status.206" id="rfc.xref.status.206.1" title="206 Partial Content">4.1</a> and <a href="#header.if-range" id="rfc.xref.header.if-range.4" title="If-Range">6.3</a>)
1093            </p>
1094            <p id="rfc.section.B.1.p.4">Fix problem with unsatisfiable range requests; there are two cases: syntactic problems, and range doesn't exist in the document.
1095               The 416 status code was needed to resolve this ambiguity needed to indicate an error for a byte range request that falls outside
1096               of the actual contents of a document. (Section <a href="#status.416" id="rfc.xref.status.416.2" title="416 Requested Range Not Satisfiable">4.2</a>, <a href="#header.content-range" id="rfc.xref.header.content-range.7" title="Content-Range">6.2</a>)
1097            </p>
1098         </div>
1099         <div id="changes.from.rfc.2616">
1100            <h2 id="rfc.section.B.2"><a href="#rfc.section.B.2">B.2</a>&nbsp;<a href="#changes.from.rfc.2616">Changes from RFC 2616</a></h2>
1101            <p id="rfc.section.B.2.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;4.1</a>)
1102            </p>
1103         </div>
1104      </div>
1105      <div id="change.log">
1106         <h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a>&nbsp;<a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a></h1>
1107         <div>
1108            <h2 id="rfc.section.C.1"><a href="#rfc.section.C.1">C.1</a>&nbsp;Since RFC2616
1109            </h2>
1110            <p id="rfc.section.C.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>.
1111            </p>
1112         </div>
1113         <div>
1114            <h2 id="rfc.section.C.2"><a href="#rfc.section.C.2">C.2</a>&nbsp;Since draft-ietf-httpbis-p5-range-00
1115            </h2>
1116            <p id="rfc.section.C.2.p.1">Closed issues: </p>
1117            <ul>
1118               <li>&lt;<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/18">http://www3.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;)
1119               </li>
1120               <li>&lt;<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35</a>&gt;: "Normative and Informative references"
1121               </li>
1122               <li>&lt;<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86</a>&gt;: "Normative up-to-date references"
1123               </li>
1124            </ul>
1125         </div>
1126         <div>
1127            <h2 id="rfc.section.C.3"><a href="#rfc.section.C.3">C.3</a>&nbsp;Since draft-ietf-httpbis-p5-range-01
1128            </h2>
1129            <p id="rfc.section.C.3.p.1">Closed issues: </p>
1130            <ul>
1131               <li>&lt;<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/55">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/55</a>&gt;: "Updating to RFC4288"
1132               </li>
1133            </ul>
1134            <p id="rfc.section.C.3.p.2">Ongoing work on ABNF conversion (&lt;<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/36">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
1135            </p>
1136            <ul>
1137               <li>Add explicit references to BNF syntax and rules imported from other parts of the specification.</li>
1138            </ul>
1139         </div>
1140         <div id="changes.since.02">
1141            <h2 id="rfc.section.C.4"><a href="#rfc.section.C.4">C.4</a>&nbsp;<a href="#changes.since.02">Since draft-ietf-httpbis-p5-range-02</a></h2>
1142            <p id="rfc.section.C.4.p.1">Ongoing work on IANA Message Header Registration (&lt;<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/40">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/40</a>&gt;):
1143            </p>
1144            <ul>
1145               <li>Reference RFC 3984, and update header registrations for headers defined in this document.</li>
1146            </ul>
1147         </div>
1148         <div id="changes.since.03">
1149            <h2 id="rfc.section.C.5"><a href="#rfc.section.C.5">C.5</a>&nbsp;<a href="#changes.since.03">Since draft-ietf-httpbis-p5-range-03</a></h2>
1150         </div>
1151      </div>
1152      <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1>
1153      <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> 
1154      </p>
1155      <div class="print2col">
1156         <ul class="ind">
1157            <li><a id="rfc.index.2" href="#rfc.index.2"><b>2</b></a><ul>
1158                  <li>206 Partial Content (status code)&nbsp;&nbsp;<a href="#rfc.iref.2.1"><b>4.1</b></a>, <a href="#rfc.xref.status.206.1">B.1</a>, <a href="#rfc.xref.status.206.2">B.2</a></li>
1159               </ul>
1160            </li>
1161            <li><a id="rfc.index.4" href="#rfc.index.4"><b>4</b></a><ul>
1162                  <li>416 Requested Range Not Satisfiable (status code)&nbsp;&nbsp;<a href="#rfc.iref.4.1"><b>4.2</b></a>, <a href="#rfc.xref.status.416.1">6.2</a>, <a href="#rfc.xref.status.416.2">B.1</a></li>
1163               </ul>
1164            </li>
1165            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
1166                  <li>Accept-Ranges header&nbsp;&nbsp;<a href="#rfc.iref.a.1"><b>6.1</b></a>, <a href="#rfc.xref.header.accept-ranges.1">7.1</a></li>
1167               </ul>
1168            </li>
1169            <li><a id="rfc.index.C" href="#rfc.index.C"><b>C</b></a><ul>
1170                  <li>Content-Range header&nbsp;&nbsp;<a href="#rfc.xref.header.content-range.1">3</a>, <a href="#rfc.xref.header.content-range.2">4.1</a>, <a href="#rfc.xref.header.content-range.3">4.2</a>, <a href="#rfc.iref.c.1"><b>6.2</b></a>, <a href="#rfc.xref.header.content-range.4">7.1</a>, <a href="#rfc.xref.header.content-range.5">B.1</a>, <a href="#rfc.xref.header.content-range.6">B.1</a>, <a href="#rfc.xref.header.content-range.7">B.1</a></li>
1171               </ul>
1172            </li>
1173            <li><a id="rfc.index.G" href="#rfc.index.G"><b>G</b></a><ul>
1174                  <li><tt>Grammar</tt>&nbsp;&nbsp;
1175                     <ul>
1176                        <li><tt>Accept-Ranges</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.4"><b>6.1</b></a></li>
1177                        <li><tt>acceptable-ranges</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>6.1</b></a></li>
1178                        <li><tt>byte-content-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>6.2</b></a></li>
1179                        <li><tt>byte-range-resp-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>6.2</b></a></li>
1180                        <li><tt>byte-range-set</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.14"><b>6.4.1</b></a></li>
1181                        <li><tt>byte-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.15"><b>6.4.1</b></a></li>
1182                        <li><tt>byte-ranges-specifier</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.13"><b>6.4.1</b></a></li>
1183                        <li><tt>bytes-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.2"><b>3</b></a></li>
1184                        <li><tt>Content-Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>6.2</b></a></li>
1185                        <li><tt>content-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>6.2</b></a></li>
1186                        <li><tt>first-byte-pos</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.16"><b>6.4.1</b></a></li>
1187                        <li><tt>If-Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.11"><b>6.3</b></a></li>
1188                        <li><tt>instance-length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>6.2</b></a></li>
1189                        <li><tt>last-byte-pos</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.17"><b>6.4.1</b></a></li>
1190                        <li><tt>other-range-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>3</b></a></li>
1191                        <li><tt>Range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.20"><b>6.4.2</b></a></li>
1192                        <li><tt>range-unit</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>3</b></a></li>
1193                        <li><tt>ranges-specifier</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.12"><b>6.4.1</b></a></li>
1194                        <li><tt>suffix-byte-range-spec</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.18"><b>6.4.1</b></a></li>
1195                        <li><tt>suffix-length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.19"><b>6.4.1</b></a></li>
1196                     </ul>
1197                  </li>
1198               </ul>
1199            </li>
1200            <li><a id="rfc.index.H" href="#rfc.index.H"><b>H</b></a><ul>
1201                  <li>Headers&nbsp;&nbsp;
1202                     <ul>
1203                        <li>Accept-Ranges&nbsp;&nbsp;<a href="#rfc.iref.h.1"><b>6.1</b></a>, <a href="#rfc.xref.header.accept-ranges.1">7.1</a></li>
1204                        <li>Content-Range&nbsp;&nbsp;<a href="#rfc.xref.header.content-range.1">3</a>, <a href="#rfc.xref.header.content-range.2">4.1</a>, <a href="#rfc.xref.header.content-range.3">4.2</a>, <a href="#rfc.iref.h.2"><b>6.2</b></a>, <a href="#rfc.xref.header.content-range.4">7.1</a>, <a href="#rfc.xref.header.content-range.5">B.1</a>, <a href="#rfc.xref.header.content-range.6">B.1</a>, <a href="#rfc.xref.header.content-range.7">B.1</a></li>
1205                        <li>If-Range&nbsp;&nbsp;<a href="#rfc.xref.header.if-range.1">4.1</a>, <a href="#rfc.iref.h.3"><b>6.3</b></a>, <a href="#rfc.xref.header.if-range.2">6.4.2</a>, <a href="#rfc.xref.header.if-range.3">7.1</a>, <a href="#rfc.xref.header.if-range.4">B.1</a></li>
1206                        <li>Range&nbsp;&nbsp;<a href="#rfc.xref.header.range.1">3</a>, <a href="#rfc.xref.header.range.2">4.1</a>, <a href="#rfc.xref.header.range.3">4.2</a>, <a href="#rfc.iref.h.4"><b>6.4</b></a>, <a href="#rfc.xref.header.range.4">7.1</a></li>
1207                     </ul>
1208                  </li>
1209               </ul>
1210            </li>
1211            <li><a id="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul>
1212                  <li>If-Range header&nbsp;&nbsp;<a href="#rfc.xref.header.if-range.1">4.1</a>, <a href="#rfc.iref.i.1"><b>6.3</b></a>, <a href="#rfc.xref.header.if-range.2">6.4.2</a>, <a href="#rfc.xref.header.if-range.3">7.1</a>, <a href="#rfc.xref.header.if-range.4">B.1</a></li>
1213               </ul>
1214            </li>
1215            <li><a id="rfc.index.M" href="#rfc.index.M"><b>M</b></a><ul>
1216                  <li>Media Type&nbsp;&nbsp;
1217                     <ul>
1218                        <li>multipart/byteranges&nbsp;&nbsp;<a href="#rfc.iref.m.1"><b>A</b></a></li>
1219                        <li>multipart/x-byteranges&nbsp;&nbsp;<a href="#rfc.iref.m.4">A</a></li>
1220                     </ul>
1221                  </li>
1222                  <li>multipart/byteranges Media Type&nbsp;&nbsp;<a href="#rfc.iref.m.2"><b>A</b></a></li>
1223                  <li>multipart/x-byteranges Media Type&nbsp;&nbsp;<a href="#rfc.iref.m.3">A</a></li>
1224               </ul>
1225            </li>
1226            <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul>
1227                  <li><em>Part1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">2</a>, <a href="#rfc.xref.Part1.2">2</a>, <a href="#rfc.xref.Part1.3">2</a>, <a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.7">8</a>, <a href="#Part1"><b>10.1</b></a>, <a href="#rfc.xref.Part1.8">B.1</a><ul>
1228                        <li><em>Section 2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.1">2</a></li>
1229                        <li><em>Section 2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.2">2</a>, <a href="#rfc.xref.Part1.3">2</a>, <a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.5">2</a></li>
1230                        <li><em>Section 3.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.6">2</a></li>
1231                     </ul>
1232                  </li>
1233                  <li><em>Part3</em>&nbsp;&nbsp;<a href="#Part3"><b>10.1</b></a>, <a href="#rfc.xref.Part3.1">B.1</a></li>
1234                  <li><em>Part4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">2</a>, <a href="#rfc.xref.Part4.2">5</a>, <a href="#Part4"><b>10.1</b></a><ul>
1235                        <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.1">2</a></li>
1236                        <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part4.2">5</a></li>
1237                     </ul>
1238                  </li>
1239                  <li><em>Part6</em>&nbsp;&nbsp;<a href="#Part6"><b>10.1</b></a>, <a href="#rfc.xref.Part6.1">B.1</a></li>
1240               </ul>
1241            </li>
1242            <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul>
1243                  <li>Range header&nbsp;&nbsp;<a href="#rfc.xref.header.range.1">3</a>, <a href="#rfc.xref.header.range.2">4.1</a>, <a href="#rfc.xref.header.range.3">4.2</a>, <a href="#rfc.iref.r.1"><b>6.4</b></a>, <a href="#rfc.xref.header.range.4">7.1</a></li>
1244                  <li><em>RFC2046</em>&nbsp;&nbsp;<a href="#RFC2046"><b>10.1</b></a>, <a href="#rfc.xref.RFC2046.1">A</a>, <a href="#rfc.xref.RFC2046.2">A</a></li>
1245                  <li><em>RFC2119</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2119.1">1.1</a>, <a href="#RFC2119"><b>10.1</b></a></li>
1246                  <li><em>RFC2616</em>&nbsp;&nbsp;<a href="#RFC2616"><b>10.2</b></a>, <a href="#rfc.xref.RFC2616.1">C.1</a></li>
1247                  <li><em>RFC3864</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3864.1">7.1</a>, <a href="#RFC3864"><b>10.2</b></a></li>
1248                  <li><em>RFC4288</em>&nbsp;&nbsp;<a href="#RFC4288"><b>10.2</b></a>, <a href="#rfc.xref.RFC4288.1">A</a></li>
1249               </ul>
1250            </li>
1251            <li><a id="rfc.index.S" href="#rfc.index.S"><b>S</b></a><ul>
1252                  <li>Status Codes&nbsp;&nbsp;
1253                     <ul>
1254                        <li>206 Partial Content&nbsp;&nbsp;<a href="#rfc.iref.s.1"><b>4.1</b></a>, <a href="#rfc.xref.status.206.1">B.1</a>, <a href="#rfc.xref.status.206.2">B.2</a></li>
1255                        <li>416 Requested Range Not Satisfiable&nbsp;&nbsp;<a href="#rfc.iref.s.2"><b>4.2</b></a>, <a href="#rfc.xref.status.416.1">6.2</a>, <a href="#rfc.xref.status.416.2">B.1</a></li>
1256                     </ul>
1257                  </li>
1258               </ul>
1259            </li>
1260         </ul>
1261      </div>
1262      <div class="avoidbreak">
1263         <h1 id="rfc.authors"><a href="#rfc.authors">Authors' Addresses</a></h1>
1264         <p><b>Roy T. Fielding</b>
1265            (editor)
1266            <br>Day Software<br>23 Corporate Plaza DR, Suite 280<br>Newport Beach, CA&nbsp;92660<br>USA<br>Phone: <a href="tel:+1-949-706-5300">+1-949-706-5300</a><br>Fax: <a href="fax:+1-949-706-5305">+1-949-706-5305</a><br>EMail: <a href="mailto:fielding@gbiv.com">fielding@gbiv.com</a><br>URI: <a href="http://roy.gbiv.com/">http://roy.gbiv.com/</a></p>
1267         <p><b>Jim Gettys</b><br>One Laptop per Child<br>21 Oak Knoll Road<br>Carlisle, MA&nbsp;01741<br>USA<br>EMail: <a href="mailto:jg@laptop.org">jg@laptop.org</a><br>URI: <a href="http://www.laptop.org/">http://www.laptop.org/</a></p>
1268         <p><b>Jeffrey C. Mogul</b><br>Hewlett-Packard Company<br>HP Labs, Large Scale Systems Group<br>1501 Page Mill Road, MS 1177<br>Palo Alto, CA&nbsp;94304<br>USA<br>EMail: <a href="mailto:JeffMogul@acm.org">JeffMogul@acm.org</a></p>
1269         <p><b>Henrik Frystyk Nielsen</b><br>Microsoft Corporation<br>1 Microsoft Way<br>Redmond, WA&nbsp;98052<br>USA<br>EMail: <a href="mailto:henrikn@microsoft.com">henrikn@microsoft.com</a></p>
1270         <p><b>Larry Masinter</b><br>Adobe Systems, Incorporated<br>345 Park Ave<br>San Jose, CA&nbsp;95110<br>USA<br>EMail: <a href="mailto:LMM@acm.org">LMM@acm.org</a><br>URI: <a href="http://larry.masinter.net/">http://larry.masinter.net/</a></p>
1271         <p><b>Paul J. Leach</b><br>Microsoft Corporation<br>1 Microsoft Way<br>Redmond, WA&nbsp;98052<br>EMail: <a href="mailto:paulle@microsoft.com">paulle@microsoft.com</a></p>
1272         <p><b>Tim Berners-Lee</b><br>World Wide Web Consortium<br>MIT Computer Science and Artificial Intelligence Laboratory<br>The Stata Center, Building 32<br>32 Vassar Street<br>Cambridge, MA&nbsp;02139<br>USA<br>EMail: <a href="mailto:timbl@w3.org">timbl@w3.org</a><br>URI: <a href="http://www.w3.org/People/Berners-Lee/">http://www.w3.org/People/Berners-Lee/</a></p>
1273         <p><b>Yves Lafon</b>
1274            (editor)
1275            <br>World Wide Web Consortium<br>W3C / ERCIM<br>2004, rte des Lucioles<br>Sophia-Antipolis, AM&nbsp;06902<br>France<br>EMail: <a href="mailto:ylafon@w3.org">ylafon@w3.org</a><br>URI: <a href="http://www.raubacapeu.net/people/yves/">http://www.raubacapeu.net/people/yves/</a></p>
1276         <p><b>Julian F. Reschke</b>
1277            (editor)
1278            <br>greenbytes GmbH<br>Hafenweg 16<br>Muenster, NW&nbsp;48155<br>Germany<br>Phone: <a href="tel:+492512807760">+49 251 2807760</a><br>Fax: <a href="fax:+492512807761">+49 251 2807761</a><br>EMail: <a href="mailto:julian.reschke@greenbytes.de">julian.reschke@greenbytes.de</a><br>URI: <a href="http://greenbytes.de/tech/webdav/">http://greenbytes.de/tech/webdav/</a></p>
1279      </div>
1280      <div id="rfc.copyright">
1281         <h1><a href="#rfc.copyright">Full Copyright Statement</a></h1>
1282         <p>Copyright © The IETF Trust (2008).</p>
1283         <p>This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the
1284            authors retain all their rights.
1285         </p>
1286         <p>This document and the information contained herein are provided on an “AS IS” basis and THE CONTRIBUTOR, THE ORGANIZATION
1287            HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE
1288            DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN
1289            WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
1290         </p>
1291      </div>
1292      <div id="rfc.ipr">
1293         <h1><a href="#rfc.ipr">Intellectual Property</a></h1>
1294         <p>The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might
1295            be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any
1296            license under such rights might or might not be available; nor does it represent that it has made any independent effort to
1297            identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and
1298            BCP 79.
1299         </p>
1300         <p>Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result
1301            of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users
1302            of this specification can be obtained from the IETF on-line IPR repository at <a href="http://www.ietf.org/ipr">http://www.ietf.org/ipr</a>.
1303         </p>
1304         <p>The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary
1305            rights that may cover technology that may be required to implement this standard. Please address the information to the IETF
1306            at <a href="mailto:ietf-ipr@ietf.org">ietf-ipr@ietf.org</a>.
1307         </p>
1308      </div>
1309   </body>
1310</html>
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