source: draft-ietf-httpbis/latest/p5-range.xml @ 1383

Last change on this file since 1383 was 1383, checked in by julian.reschke@…, 8 years ago

fix ABNF ection refs due to change [1380]

  • Property svn:eol-style set to native
File size: 65.1 KB
Line 
1<?xml version="1.0" encoding="utf-8"?>
2<?xml-stylesheet type='text/xsl' href='../myxml2rfc.xslt'?>
3<!DOCTYPE rfc [
4  <!ENTITY MAY "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MAY</bcp14>">
5  <!ENTITY MUST "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST</bcp14>">
6  <!ENTITY MUST-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST NOT</bcp14>">
7  <!ENTITY OPTIONAL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>OPTIONAL</bcp14>">
8  <!ENTITY RECOMMENDED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>RECOMMENDED</bcp14>">
9  <!ENTITY REQUIRED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>REQUIRED</bcp14>">
10  <!ENTITY SHALL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL</bcp14>">
11  <!ENTITY SHALL-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL NOT</bcp14>">
12  <!ENTITY SHOULD "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD</bcp14>">
13  <!ENTITY SHOULD-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD NOT</bcp14>">
14  <!ENTITY ID-VERSION "latest">
15  <!ENTITY ID-MONTH "August">
16  <!ENTITY ID-YEAR "2011">
17  <!ENTITY notation                   "<xref target='Part1' x:rel='#notation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
18  <!ENTITY notation-abnf              "<xref target='Part1' x:rel='#notation.abnf' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
19  <!ENTITY acks                       "<xref target='Part1' x:rel='#acks' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
20  <!ENTITY basic-rules                "<xref target='Part1' x:rel='#basic.rules' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
21  <!ENTITY full-date                  "<xref target='Part1' x:rel='#date.time.formats.full.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
22  <!ENTITY messaging                  "<xref target='Part1' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY entity-tags                "<xref target='Part4' x:rel='#header.etag' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY weak-and-strong-validators "<xref target='Part4' x:rel='#weak.and.strong.validators' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY lastmod-comparison         "<xref target='Part4' x:rel='#lastmod.comparison' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26]>
27<?rfc toc="yes" ?>
28<?rfc symrefs="yes" ?>
29<?rfc sortrefs="yes" ?>
30<?rfc compact="yes"?>
31<?rfc subcompact="no" ?>
32<?rfc linkmailto="no" ?>
33<?rfc editing="no" ?>
34<?rfc comments="yes"?>
35<?rfc inline="yes"?>
36<?rfc rfcedstyle="yes"?>
37<?rfc-ext allow-markup-in-artwork="yes" ?>
38<?rfc-ext include-references-in-index="yes" ?>
39<rfc obsoletes="2616" category="std" x:maturity-level="draft"
40     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p5-range-&ID-VERSION;"     xmlns:x='http://purl.org/net/xml2rfc/ext'>
41<front>
42
43  <title abbrev="HTTP/1.1, Part 5">HTTP/1.1, part 5: Range Requests and Partial Responses</title>
44
45  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
46    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
47    <address>
48      <postal>
49        <street>345 Park Ave</street>
50        <city>San Jose</city>
51        <region>CA</region>
52        <code>95110</code>
53        <country>USA</country>
54      </postal>
55      <email>fielding@gbiv.com</email>
56      <uri>http://roy.gbiv.com/</uri>
57    </address>
58  </author>
59
60  <author initials="J." surname="Gettys" fullname="Jim Gettys">
61    <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
62    <address>
63      <postal>
64        <street>21 Oak Knoll Road</street>
65        <city>Carlisle</city>
66        <region>MA</region>
67        <code>01741</code>
68        <country>USA</country>
69      </postal>
70      <email>jg@freedesktop.org</email>
71      <uri>http://gettys.wordpress.com/</uri>
72    </address>
73  </author>
74 
75  <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
76    <organization abbrev="HP">Hewlett-Packard Company</organization>
77    <address>
78      <postal>
79        <street>HP Labs, Large Scale Systems Group</street>
80        <street>1501 Page Mill Road, MS 1177</street>
81        <city>Palo Alto</city>
82        <region>CA</region>
83        <code>94304</code>
84        <country>USA</country>
85      </postal>
86      <email>JeffMogul@acm.org</email>
87    </address>
88  </author>
89
90  <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
91    <organization abbrev="Microsoft">Microsoft Corporation</organization>
92    <address>
93      <postal>
94        <street>1 Microsoft Way</street>
95        <city>Redmond</city>
96        <region>WA</region>
97        <code>98052</code>
98        <country>USA</country>
99      </postal>
100      <email>henrikn@microsoft.com</email>
101    </address>
102  </author>
103
104  <author initials="L." surname="Masinter" fullname="Larry Masinter">
105    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
106    <address>
107      <postal>
108        <street>345 Park Ave</street>
109        <city>San Jose</city>
110        <region>CA</region>
111        <code>95110</code>
112        <country>USA</country>
113      </postal>
114      <email>LMM@acm.org</email>
115      <uri>http://larry.masinter.net/</uri>
116    </address>
117  </author>
118 
119  <author initials="P." surname="Leach" fullname="Paul J. Leach">
120    <organization abbrev="Microsoft">Microsoft Corporation</organization>
121    <address>
122      <postal>
123        <street>1 Microsoft Way</street>
124        <city>Redmond</city>
125        <region>WA</region>
126        <code>98052</code>
127      </postal>
128      <email>paulle@microsoft.com</email>
129    </address>
130  </author>
131   
132  <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
133    <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
134    <address>
135      <postal>
136        <street>MIT Computer Science and Artificial Intelligence Laboratory</street>
137        <street>The Stata Center, Building 32</street>
138        <street>32 Vassar Street</street>
139        <city>Cambridge</city>
140        <region>MA</region>
141        <code>02139</code>
142        <country>USA</country>
143      </postal>
144      <email>timbl@w3.org</email>
145      <uri>http://www.w3.org/People/Berners-Lee/</uri>
146    </address>
147  </author>
148
149  <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
150    <organization abbrev="W3C">World Wide Web Consortium</organization>
151    <address>
152      <postal>
153        <street>W3C / ERCIM</street>
154        <street>2004, rte des Lucioles</street>
155        <city>Sophia-Antipolis</city>
156        <region>AM</region>
157        <code>06902</code>
158        <country>France</country>
159      </postal>
160      <email>ylafon@w3.org</email>
161      <uri>http://www.raubacapeu.net/people/yves/</uri>
162    </address>
163  </author>
164
165  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
166    <organization abbrev="greenbytes">greenbytes GmbH</organization>
167    <address>
168      <postal>
169        <street>Hafenweg 16</street>
170        <city>Muenster</city><region>NW</region><code>48155</code>
171        <country>Germany</country>
172      </postal>
173      <phone>+49 251 2807760</phone>
174      <facsimile>+49 251 2807761</facsimile>
175      <email>julian.reschke@greenbytes.de</email>
176      <uri>http://greenbytes.de/tech/webdav/</uri>
177    </address>
178  </author>
179
180  <date month="&ID-MONTH;" year="&ID-YEAR;"/>
181  <workgroup>HTTPbis Working Group</workgroup>
182
183<abstract>
184<t>
185   The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
186   distributed, collaborative, hypertext information systems. HTTP has been in
187   use by the World Wide Web global information initiative since 1990. This
188   document is Part 5 of the seven-part specification that defines the protocol
189   referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
190</t>
191<t>
192   Part 5 defines range-specific requests and the rules for constructing and
193   combining responses to those requests.
194</t>
195</abstract>
196
197<note title="Editorial Note (To be removed by RFC Editor)">
198  <t>
199    Discussion of this draft should take place on the HTTPBIS working group
200    mailing list (ietf-http-wg@w3.org), which is archived at
201    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
202  </t>
203  <t>
204    The current issues list is at
205    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
206    documents (including fancy diffs) can be found at
207    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
208  </t>
209  <t>
210    The changes in this draft are summarized in <xref target="changes.since.15"/>.
211  </t>
212</note>
213</front>
214<middle>
215<section title="Introduction" anchor="introduction">
216<t>
217   HTTP clients often encounter interrupted data transfers as a result
218   of cancelled requests or dropped connections.  When a client has stored
219   a partial representation, it is desirable to request the remainder
220   of that representation in a subsequent request rather than transfer
221   the entire representation.
222   There are also a number of Web applications that benefit from being
223   able to request only a subset of a larger representation, such as a
224   single page of a very large document or only part of an image to be
225   rendered by a device with limited local storage.
226</t>
227<t>
228   This document defines HTTP/1.1 range requests,
229   partial responses, and the multipart/byteranges media type.
230   The protocol for range requests is an &OPTIONAL; feature of HTTP,
231   designed so resources or recipients that do not implement this feature
232   can respond as if it is a normal GET request without impacting
233   interoperability.  Partial responses are indicated by a distinct status
234   code to not be mistaken for full responses by intermediate caches
235   that might not implement the feature.
236</t>
237<t>
238   Although the HTTP range request mechanism is designed to allow for
239   extensible range types, this specification only defines requests for
240   byte ranges.
241</t>
242
243<section title="Requirements" anchor="intro.requirements">
244<t>
245   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
246   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
247   document are to be interpreted as described in <xref target="RFC2119"/>.
248</t>
249<t>
250   An implementation is not compliant if it fails to satisfy one or more
251   of the "MUST" or "REQUIRED" level requirements for the protocols it
252   implements. An implementation that satisfies all the "MUST" or "REQUIRED"
253   level and all the "SHOULD" level requirements for its protocols is said
254   to be "unconditionally compliant"; one that satisfies all the "MUST"
255   level requirements but not all the "SHOULD" level requirements for its
256   protocols is said to be "conditionally compliant".
257</t>
258</section>
259
260<section title="Syntax Notation" anchor="notation">
261  <x:anchor-alias value="ALPHA"/>
262  <x:anchor-alias value="CHAR"/>
263  <x:anchor-alias value="CR"/>
264  <x:anchor-alias value="DIGIT"/>
265  <x:anchor-alias value="LF"/>
266  <x:anchor-alias value="OCTET"/>
267  <x:anchor-alias value="SP"/>
268  <x:anchor-alias value="VCHAR"/>
269  <x:anchor-alias value="WSP"/>
270<t>
271  This specification uses the ABNF syntax defined in &notation; (which
272  extends the syntax defined in <xref target="RFC5234"/> with a list rule).
273  <xref target="collected.abnf"/> shows the collected ABNF, with the list
274  rule expanded.
275</t>
276<t>
277  The following core rules are included by
278  reference, as defined in <xref target="RFC5234" x:fmt="," x:sec="B.1"/>:
279  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
280  DIGIT (decimal 0-9), DQUOTE (double quote),
281  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
282  OCTET (any 8-bit sequence of data), SP (space),
283  VCHAR (any visible USASCII character),
284  and WSP (whitespace).
285</t>
286
287<section title="Core Rules" anchor="core.rules">
288  <x:anchor-alias value="token"/>
289  <x:anchor-alias value="OWS"/>
290<t>
291  The core rules below are defined in &basic-rules;:
292</t>
293<figure><artwork type="abnf2616">
294  <x:ref>token</x:ref>      = &lt;token, defined in &basic-rules;&gt;
295  <x:ref>OWS</x:ref>        = &lt;OWS, defined in &basic-rules;&gt;
296</artwork></figure>
297</section>
298
299<section title="ABNF Rules defined in other Parts of the Specification" anchor="abnf.dependencies">
300  <x:anchor-alias value="entity-tag"/>
301  <x:anchor-alias value="HTTP-date"/>
302<t>
303  The ABNF rules below are defined in other parts:
304</t>
305<figure><!--Part1--><artwork type="abnf2616">
306  <x:ref>HTTP-date</x:ref>  = &lt;HTTP-date, defined in &full-date;&gt;
307</artwork></figure>
308<figure><!--Part4--><artwork type="abnf2616">
309  <x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in &entity-tags;&gt;
310</artwork></figure>
311</section>
312
313</section>
314
315</section>
316
317
318<section title="Range Units" anchor="range.units">
319  <x:anchor-alias value="bytes-unit"/>
320  <x:anchor-alias value="other-range-unit"/>
321  <x:anchor-alias value="range-unit"/>
322<t>
323   HTTP/1.1 allows a client to request that only part (a range) of the
324   representation be included within the response. HTTP/1.1 uses range
325   units in the Range (<xref target="header.range"/>) and Content-Range (<xref target="header.content-range"/>)
326   header fields. A representation can be broken down into subranges according
327   to various structural units.
328</t>
329<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="range-unit"/><iref primary="true" item="Grammar" subitem="bytes-unit"/><iref primary="true" item="Grammar" subitem="other-range-unit"/>
330  <x:ref>range-unit</x:ref>       = <x:ref>bytes-unit</x:ref> / <x:ref>other-range-unit</x:ref>
331  <x:ref>bytes-unit</x:ref>       = "bytes"
332  <x:ref>other-range-unit</x:ref> = <x:ref>token</x:ref>
333</artwork></figure>
334<t>
335  HTTP/1.1 has been designed to allow implementations of applications
336  that do not depend on knowledge of ranges. The only range unit defined
337  by HTTP/1.1 is "bytes". Additional specifiers can be defined as described
338  in <xref target="range.specifier.registry"/>.
339</t>
340<t>
341  If a range unit is not understood in a request, a server &MUST; ignore
342  the whole Range header field (<xref target="header.range"/>).
343  If a range unit is not understood in a response, an intermediary
344  &SHOULD; pass the response to the client; a client &MUST; fail.
345</t>
346
347<section title="Range Specifier Registry" anchor="range.specifier.registry">
348<t>
349   The HTTP Range Specifier Registry defines the name space for the range
350   specifier names.
351</t>
352<t>
353   Registrations &MUST; include the following fields:
354   <list style="symbols">
355     <t>Name</t>
356     <t>Description</t>
357     <t>Pointer to specification text</t>
358   </list>
359</t>
360<t>
361  Values to be added to this name space are subject to IETF review
362  (<xref target="RFC5226" x:fmt="," x:sec="4.1"/>).
363</t>
364<t>
365   The registry itself is maintained at
366   <eref target="http://www.iana.org/assignments/http-range-specifiers"/>.
367</t>
368</section>
369
370</section>
371
372<section title="Status Code Definitions" anchor="status.code.definitions">
373<section title="206 Partial Content" anchor="status.206">
374  <iref primary="true" item="206 Partial Content (status code)" x:for-anchor=""/>
375  <iref primary="true" item="Status Codes" subitem="206 Partial Content" x:for-anchor=""/>
376<t>
377   The server has fulfilled the partial GET request for the resource.
378   The request &MUST; have included a Range header field (<xref target="header.range"/>)
379   indicating the desired range, and &MAY; have included an If-Range
380   header field (<xref target="header.if-range"/>) to make the request conditional.
381</t>
382<t>
383   The response &MUST; include the following header fields:
384  <list style="symbols">
385    <t>
386        Either a Content-Range header field (<xref target="header.content-range"/>) indicating
387        the range included with this response, or a multipart/byteranges
388        Content-Type including Content-Range fields for each part. If a
389        Content-Length header field is present in the response, its
390        value &MUST; match the actual number of octets transmitted in the
391        message-body.
392    </t>
393    <t>
394        Date
395    </t>
396    <t>
397        Cache-Control, ETag, Expires, Content-Location, Last-Modified,
398        and/or Vary, if the header field would have been sent in a 200
399        response to the same request
400    </t>
401  </list>
402</t>
403<t>
404   If the 206 response is the result of an If-Range request, the response
405   &SHOULD-NOT; include other representation header fields. Otherwise, the response
406   &MUST; include all of the representation header fields that would have been returned
407   with a 200 (OK) response to the same request.
408</t>
409</section>
410
411<section title="416 Requested Range Not Satisfiable" anchor="status.416">
412  <iref primary="true" item="416 Requested Range Not Satisfiable (status code)" x:for-anchor=""/>
413  <iref primary="true" item="Status Codes" subitem="416 Requested Range Not Satisfiable" x:for-anchor=""/>
414<t>
415   A server &SHOULD; return a response with this status code if a request
416   included a Range header field (<xref target="header.range"/>), and none of
417   the ranges-specifier values in this field overlap the current extent
418   of the selected resource, and the request did not include an If-Range
419   header field (<xref target="header.if-range"/>). (For byte-ranges,
420   this means that the first-byte-pos of all of the byte-range-spec values were
421   greater than the current length of the selected resource.)
422</t>
423<t>
424   When this status code is returned for a byte-range request, the
425   response &SHOULD; include a Content-Range header field
426   specifying the current length of the representation (see <xref target="header.content-range"/>).
427   This response &MUST-NOT; use the multipart/byteranges content-type.
428</t>
429</section>
430</section>
431
432<section title="Combining Ranges" anchor="combining.byte.ranges">
433<t>
434   A response might transfer only a subrange of a representation if the
435   connection closed prematurely or if the request used one or more Range
436   specifications.  After several such transfers, a client might have
437   received several ranges of the same representation.  These ranges can only
438   be safely combined if they all have in common the same strong validator,
439   where "strong validator" is defined to be either an entity-tag that is
440   not marked as weak (&entity-tags;) or, if no entity-tag is provided, a
441   Last-Modified value that is strong in the sense defined by
442   &lastmod-comparison;.
443</t>
444<t>
445   When a client receives an incomplete 200 (OK) or 206 (Partial Content)
446   response and already has one or more stored responses for the same method
447   and effective request URI, all of the stored responses with the same
448   strong validator &MAY; be combined with the partial content in this new
449   response.  If none of the stored responses contain the same strong
450   validator, then this new response corresponds to a new representation
451   and &MUST-NOT; be combined with the existing stored responses.
452</t>
453<t>
454   If the new response is an incomplete 200 (OK) response, then the header
455   fields of that new response are used for any combined response and replace
456   those of the matching stored responses.
457</t>
458<t>
459   If the new response is a 206 (Partial Content) response and at least one
460   of the matching stored responses is a 200 (OK), then the combined response
461   header fields consist of the most recent 200 response's header fields.
462   If all of the matching stored responses are 206 responses, then the
463   stored response with the most header fields is used as the source of
464   header fields for the combined response, except that the client &MUST;
465   use other header fields provided in the new response, aside from
466   Content-Range, to replace all instances of the corresponding header
467   fields in the stored response.
468</t>
469<t>
470   The combined response message-body consists of the union of partial
471   content ranges in the new response and each of the selected responses.
472   If the union consists of the entire range of the representation, then the
473   combined response &MUST; be recorded as a complete 200 (OK) response
474   with a Content-Length header field that reflects the complete length.
475   Otherwise, the combined response(s) &MUST; include a Content-Range
476   header field describing the included range(s) and be recorded as
477   incomplete.  If the union consists of a discontinuous range of the
478   representation, then the client &MAY; store it as either a multipart range
479   response or as multiple 206 responses with one continuous range each.
480</t>
481</section>
482
483<section title="Header Field Definitions" anchor="header.fields">
484<t>
485   This section defines the syntax and semantics of HTTP/1.1 header fields
486   related to range requests and partial responses.
487</t>
488
489<section title="Accept-Ranges" anchor="header.accept-ranges">
490  <iref primary="true" item="Accept-Ranges header field" x:for-anchor=""/>
491  <iref primary="true" item="Header Fields" subitem="Accept-Ranges" x:for-anchor=""/>
492  <x:anchor-alias value="Accept-Ranges"/>
493  <x:anchor-alias value="acceptable-ranges"/>
494<t>
495   The "Accept-Ranges" header field allows a resource to indicate
496   its acceptance of range requests.
497</t>
498<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Ranges"/><iref primary="true" item="Grammar" subitem="acceptable-ranges"/>
499  <x:ref>Accept-Ranges</x:ref>     = <x:ref>acceptable-ranges</x:ref>
500  <x:ref>acceptable-ranges</x:ref> = 1#<x:ref>range-unit</x:ref> / "none"
501</artwork></figure>
502<t>
503      Origin servers that accept byte-range requests &MAY; send
504</t>
505<figure><artwork type="example">
506  Accept-Ranges: bytes
507</artwork></figure>
508<t>
509      but are not required to do so. Clients &MAY; generate range
510      requests without having received this header field for the resource
511      involved. Range units are defined in <xref target="range.units"/>.
512</t>
513<t>
514      Servers that do not accept any kind of range request for a
515      resource &MAY; send
516</t>
517<figure><artwork type="example">
518  Accept-Ranges: none
519</artwork></figure>
520<t>
521      to advise the client not to attempt a range request.
522</t>
523</section>
524
525<section title="Content-Range" anchor="header.content-range">
526  <iref primary="true" item="Content-Range header field" x:for-anchor=""/>
527  <iref primary="true" item="Header Fields" subitem="Content-Range" x:for-anchor=""/>
528  <x:anchor-alias value="byte-content-range-spec"/>
529  <x:anchor-alias value="byte-range-resp-spec"/>
530  <x:anchor-alias value="Content-Range"/>
531  <x:anchor-alias value="content-range-spec"/>
532  <x:anchor-alias value="instance-length"/>
533  <x:anchor-alias value="other-content-range-spec"/>
534  <x:anchor-alias value="other-range-resp-spec"/>
535<t>
536   The "Content-Range" header field is sent with a partial representation to
537   specify where in the full representation the payload body is intended to be
538   applied.
539</t>
540<t>   
541   Range units are defined in <xref target="range.units"/>.
542</t>
543<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Range"/><iref primary="true" item="Grammar" subitem="content-range-spec"/><iref primary="true" item="Grammar" subitem="byte-content-range-spec"/><iref primary="true" item="Grammar" subitem="byte-range-resp-spec"/><iref primary="true" item="Grammar" subitem="instance-length"/>
544  <x:ref>Content-Range</x:ref> = <x:ref>content-range-spec</x:ref>
545 
546  <x:ref>content-range-spec</x:ref>      = <x:ref>byte-content-range-spec</x:ref>
547                          / <x:ref>other-content-range-spec</x:ref>
548  <x:ref>byte-content-range-spec</x:ref> = <x:ref>bytes-unit</x:ref> <x:ref>SP</x:ref>
549                            <x:ref>byte-range-resp-spec</x:ref> "/"
550                            ( <x:ref>instance-length</x:ref> / "*" )
551 
552  <x:ref>byte-range-resp-spec</x:ref>    = (<x:ref>first-byte-pos</x:ref> "-" <x:ref>last-byte-pos</x:ref>)
553                          / "*"
554                         
555  <x:ref>instance-length</x:ref>         = 1*<x:ref>DIGIT</x:ref>
556 
557  <x:ref>other-content-range-spec</x:ref> = <x:ref>other-range-unit</x:ref> <x:ref>SP</x:ref>
558                             <x:ref>other-range-resp-spec</x:ref>
559  <x:ref>other-range-resp-spec</x:ref>    = *<x:ref>CHAR</x:ref>
560</artwork></figure>
561<t>
562   The header field &SHOULD; indicate the total length of the full representation,
563   unless this length is unknown or difficult to determine. The asterisk
564   "*" character means that the instance-length is unknown at the time
565   when the response was generated.
566</t>
567<t>
568   Unlike byte-ranges-specifier values (see <xref target="byte.ranges"/>), a byte-range-resp-spec
569   &MUST; only specify one range, and &MUST; contain
570   absolute byte positions for both the first and last byte of the
571   range.
572</t>
573<t>
574   A byte-content-range-spec with a byte-range-resp-spec whose last-byte-pos
575   value is less than its first-byte-pos value, or whose
576   instance-length value is less than or equal to its last-byte-pos
577   value, is invalid. The recipient of an invalid byte-content-range-spec
578   &MUST; ignore it and any content transferred along with it.
579</t>
580<t>
581   In the case of a byte range request:
582   A server sending a response with status code 416 (Requested range not
583   satisfiable) &SHOULD; include a Content-Range field with a byte-range-resp-spec
584   of "*". The instance-length specifies the current length of
585   the selected resource. A response with status code 206 (Partial
586   Content) &MUST-NOT; include a Content-Range field with a byte-range-resp-spec of "*".
587</t>
588<t>
589   Examples of byte-content-range-spec values, assuming that the representation
590   contains a total of 1234 bytes:
591   <list style="symbols">
592      <t>
593        The first 500 bytes:
594<figure><artwork type="example" x:indent-with="   ">
595  bytes 0-499/1234
596</artwork></figure>
597      </t>   
598      <t>
599        The second 500 bytes:
600<figure><artwork type="example" x:indent-with="   ">
601  bytes 500-999/1234
602</artwork></figure>
603      </t>   
604      <t>
605        All except for the first 500 bytes:
606<figure><artwork type="example" x:indent-with="   ">
607  bytes 500-1233/1234
608</artwork></figure>
609      </t>   
610      <t>
611        The last 500 bytes:
612<figure><artwork type="example" x:indent-with="   ">
613  bytes 734-1233/1234
614</artwork></figure>
615      </t>   
616   </list>
617</t>
618<t>
619   When an HTTP message includes the content of a single range (for
620   example, a response to a request for a single range, or to a request
621   for a set of ranges that overlap without any holes), this content is
622   transmitted with a Content-Range header field, and a Content-Length header
623   field showing the number of bytes actually transferred. For example,
624</t>
625<figure><artwork type="example">
626  HTTP/1.1 206 Partial Content
627  Date: Wed, 15 Nov 1995 06:25:24 GMT
628  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
629  Content-Range: bytes 21010-47021/47022
630  Content-Length: 26012
631  Content-Type: image/gif
632</artwork></figure>
633<t>
634   When an HTTP message includes the content of multiple ranges (for
635   example, a response to a request for multiple non-overlapping
636   ranges), these are transmitted as a multipart message. The multipart
637   media type used for this purpose is "multipart/byteranges" as defined
638   in <xref target="internet.media.type.multipart.byteranges"/>.
639</t>
640<t>
641   A response to a request for a single range &MUST-NOT; be sent using the
642   multipart/byteranges media type.  A response to a request for
643   multiple ranges, whose result is a single range, &MAY; be sent as a
644   multipart/byteranges media type with one part. A client that cannot
645   decode a multipart/byteranges message &MUST-NOT; ask for multiple
646   ranges in a single request.
647</t>
648<t>
649   When a client requests multiple ranges in one request, the
650   server &SHOULD; return them in the order that they appeared in the
651   request.
652</t>
653<t>
654   If the server ignores a byte-range-spec because it is syntactically
655   invalid, the server &SHOULD; treat the request as if the invalid Range
656   header field did not exist. (Normally, this means return a 200
657   response containing the full representation).
658</t>
659<t>
660   If the server receives a request (other than one including an If-Range
661   header field) with an unsatisfiable Range header
662   field (that is, all of whose byte-range-spec values have a
663   first-byte-pos value greater than the current length of the selected
664   resource), it &SHOULD; return a response code of 416 (Requested range
665   not satisfiable) (<xref target="status.416"/>).
666</t>
667<x:note>
668  <t>
669    <x:h>Note:</x:h> Clients cannot depend on servers to send a 416 (Requested
670    range not satisfiable) response instead of a 200 (OK) response for
671    an unsatisfiable Range header field, since not all servers
672    implement this header field.
673  </t>
674</x:note>
675</section>
676
677<section title="If-Range" anchor="header.if-range">
678  <iref primary="true" item="If-Range header field" x:for-anchor=""/>
679  <iref primary="true" item="Header Fields" subitem="If-Range" x:for-anchor=""/>
680  <x:anchor-alias value="If-Range"/>
681<t>
682   If a client has a partial copy of a representation and wishes
683   to have an up-to-date copy of the entire representation, it
684   could use the Range header field with a conditional GET (using
685   either or both of If-Unmodified-Since and If-Match.) However, if the
686   condition fails because the representation has been modified, the client
687   would then have to make a second request to obtain the entire current
688   representation.
689</t>
690<t>
691   The "If-Range" header field allows a client to "short-circuit" the second
692   request. Informally, its meaning is "if the representation is unchanged, send
693   me the part(s) that I am missing; otherwise, send me the entire new
694   representation".
695</t>
696<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="If-Range"/>
697  <x:ref>If-Range</x:ref> = <x:ref>entity-tag</x:ref> / <x:ref>HTTP-date</x:ref>
698</artwork></figure>
699<t>
700   Clients &MUST-NOT; use an entity-tag marked as weak in an If-Range
701   field value and &MUST-NOT; use a Last-Modified date in an If-Range
702   field value unless it has no entity-tag for the representation and
703   the Last-Modified date it does have for the representation is strong
704   in the sense defined by &lastmod-comparison;.
705</t>
706<t>
707   A server that evaluates a conditional range request that is applicable
708   to one of its representations &MUST; evaluate the condition as false if
709   the entity-tag used as a validator is marked as weak or, when an HTTP-date
710   is used as the validator, if the date value is not strong in the sense
711   defined by &lastmod-comparison;. (A server can distinguish between a
712   valid HTTP-date and any form of entity-tag by examining the first
713   two characters.)
714</t>
715<t>
716   The If-Range header field &SHOULD; only be sent by clients together with
717   a Range header field.  The If-Range header field &MUST; be ignored if it
718   is received in a request that does not include a Range header field.
719   The If-Range header field &MUST; be ignored by a server that does not
720   support the sub-range operation.
721</t>
722<t>
723   If the validator given in the If-Range header field matches the current
724   validator for the selected representation of the target resource, then
725   the server &SHOULD; send the specified sub-range of the representation
726   using a 206 (Partial Content) response. If the validator does not match,
727   then the server &SHOULD; send the entire representation using a 200 (OK)
728   response.
729</t>
730</section>
731
732<section title="Range" anchor="header.range">
733  <iref primary="true" item="Range header field" x:for-anchor=""/>
734  <iref primary="true" item="Header Fields" subitem="Range" x:for-anchor=""/>
735
736<section title="Byte Ranges" anchor="byte.ranges">
737<t>
738   Since all HTTP representations are transferred as sequences
739   of bytes, the concept of a byte range is meaningful for any HTTP
740   representation. (However, not all clients and servers need to support byte-range
741   operations.)
742</t>
743<t>
744   Byte range specifications in HTTP apply to the sequence of bytes in
745   the representation body (not necessarily the same as the message-body).
746</t>
747<t anchor="rule.ranges-specifier">
748  <x:anchor-alias value="byte-range-set"/>
749  <x:anchor-alias value="byte-range-spec"/>
750  <x:anchor-alias value="byte-ranges-specifier"/>
751  <x:anchor-alias value="first-byte-pos"/>
752  <x:anchor-alias value="last-byte-pos"/>
753  <x:anchor-alias value="ranges-specifier"/>
754  <x:anchor-alias value="suffix-byte-range-spec"/>
755  <x:anchor-alias value="suffix-length"/>
756
757   A byte range operation &MAY; specify a single range of bytes, or a set
758   of ranges within a single representation.
759</t>
760<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="ranges-specifier"/><iref primary="true" item="Grammar" subitem="byte-ranges-specifier"/><iref primary="true" item="Grammar" subitem="byte-range-set"/><iref primary="true" item="Grammar" subitem="byte-range-spec"/><iref primary="true" item="Grammar" subitem="first-byte-pos"/><iref primary="true" item="Grammar" subitem="last-byte-pos"/>
761  <x:ref>byte-ranges-specifier</x:ref> = <x:ref>bytes-unit</x:ref> "=" <x:ref>byte-range-set</x:ref>
762  <x:ref>byte-range-set</x:ref>  = 1#( <x:ref>byte-range-spec</x:ref> / <x:ref>suffix-byte-range-spec</x:ref> )
763  <x:ref>byte-range-spec</x:ref> = <x:ref>first-byte-pos</x:ref> "-" [ <x:ref>last-byte-pos</x:ref> ]
764  <x:ref>first-byte-pos</x:ref>  = 1*<x:ref>DIGIT</x:ref>
765  <x:ref>last-byte-pos</x:ref>   = 1*<x:ref>DIGIT</x:ref>
766</artwork></figure>
767<t>
768   The first-byte-pos value in a byte-range-spec gives the byte-offset
769   of the first byte in a range. The last-byte-pos value gives the
770   byte-offset of the last byte in the range; that is, the byte
771   positions specified are inclusive. Byte offsets start at zero.
772</t>
773<t>
774   If the last-byte-pos value is present, it &MUST; be greater than or
775   equal to the first-byte-pos in that byte-range-spec, or the byte-range-spec
776   is syntactically invalid. The recipient of a byte-range-set
777   that includes one or more syntactically invalid byte-range-spec
778   values &MUST; ignore the header field that includes that byte-range-set.
779</t>
780<t>
781   If the last-byte-pos value is absent, or if the value is greater than
782   or equal to the current length of the representation body, last-byte-pos is
783   taken to be equal to one less than the current length of the representation
784   in bytes.
785</t>
786<t>
787   By its choice of last-byte-pos, a client can limit the number of
788   bytes retrieved without knowing the size of the representation.
789</t>
790<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="suffix-byte-range-spec"/><iref primary="true" item="Grammar" subitem="suffix-length"/>
791  <x:ref>suffix-byte-range-spec</x:ref> = "-" <x:ref>suffix-length</x:ref>
792  <x:ref>suffix-length</x:ref> = 1*<x:ref>DIGIT</x:ref>
793</artwork></figure>
794<t>
795   A suffix-byte-range-spec is used to specify the suffix of the
796   representation body, of a length given by the suffix-length value. (That is,
797   this form specifies the last N bytes of a representation.) If the
798   representation is shorter than the specified suffix-length, the entire
799   representation is used.
800</t>
801<t>
802   If a syntactically valid byte-range-set includes at least one byte-range-spec
803   whose first-byte-pos is less than the current length of
804   the representation, or at least one suffix-byte-range-spec with a non-zero
805   suffix-length, then the byte-range-set is satisfiable.
806   Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set
807   is unsatisfiable, the server &SHOULD; return a response with a
808   416 (Requested range not satisfiable) status code. Otherwise, the server
809   &SHOULD; return a response with a 206 (Partial Content) status code
810   containing the satisfiable ranges of the representation.
811</t>
812<t>
813   Examples of byte-ranges-specifier values (assuming a representation of
814   length 10000):
815  <list style="symbols">
816     <t>The first 500 bytes (byte offsets 0-499, inclusive):
817<figure><artwork type="example" x:indent-with="   ">
818  bytes=0-499
819</artwork></figure>
820    </t>
821     <t>The second 500 bytes (byte offsets 500-999, inclusive):
822<figure><artwork type="example" x:indent-with="   ">
823  bytes=500-999
824</artwork></figure>
825    </t>
826     <t>The final 500 bytes (byte offsets 9500-9999, inclusive):
827<figure><artwork type="example" x:indent-with="   ">
828  bytes=-500
829</artwork></figure>
830    Or:
831<figure><artwork type="example" x:indent-with="   ">
832  bytes=9500-
833</artwork></figure>
834    </t>
835     <t>The first and last bytes only (bytes 0 and 9999):
836<figure><artwork type="example" x:indent-with="   ">
837  bytes=0-0,-1
838</artwork></figure>
839     </t>
840     <t>Several legal but not canonical specifications of the second 500
841        bytes (byte offsets 500-999, inclusive):
842<figure><artwork type="example" x:indent-with="   ">
843  bytes=500-600,601-999
844  bytes=500-700,601-999
845</artwork></figure>
846     </t>
847  </list>
848</t>
849</section>
850
851<section title="Range Retrieval Requests" anchor="range.retrieval.requests">
852  <x:anchor-alias value="Range"/>
853  <x:anchor-alias value="other-ranges-specifier"/>
854  <x:anchor-alias value="other-range-set"/>
855<t>
856   The "Range" header field defines the GET method (conditional or
857   not) to request one or more sub-ranges of the response representation body, instead
858   of the entire representation body.
859</t>
860<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Range"/>
861  <x:ref>Range</x:ref> = <x:ref>byte-ranges-specifier</x:ref> / <x:ref>other-ranges-specifier</x:ref>
862  <x:ref>other-ranges-specifier</x:ref> = <x:ref>other-range-unit</x:ref> "=" <x:ref>other-range-set</x:ref>
863  <x:ref>other-range-set</x:ref> = 1*<x:ref>CHAR</x:ref>
864</artwork></figure>
865<t>
866   A server &MAY; ignore the Range header field. However, origin
867   servers and intermediate caches ought to support byte ranges when
868   possible, since Range supports efficient recovery from partially
869   failed transfers, and supports efficient partial retrieval of large
870   representations.
871</t>
872<t>
873   If the server supports the Range header field and the specified range or
874   ranges are appropriate for the representation:
875  <list style="symbols">
876     <t>The presence of a Range header field in an unconditional GET modifies
877        what is returned if the GET is otherwise successful. In other
878        words, the response carries a status code of 206 (Partial
879        Content) instead of 200 (OK).</t>
880
881     <t>The presence of a Range header field in a conditional GET (a request
882        using one or both of If-Modified-Since and If-None-Match, or
883        one or both of If-Unmodified-Since and If-Match) modifies what
884        is returned if the GET is otherwise successful and the
885        condition is true. It does not affect the 304 (Not Modified)
886        response returned if the conditional is false.</t>
887  </list>
888</t>
889<t>
890   In some cases, it might be more appropriate to use the If-Range
891   header field (see <xref target="header.if-range"/>) in addition to the Range
892   header field.
893</t>
894<t>
895   If a proxy that supports ranges receives a Range request, forwards
896   the request to an inbound server, and receives an entire representation in
897   reply, it &MAY; only return the requested range to its client.
898</t>
899</section>
900</section>
901</section>
902
903<section title="IANA Considerations" anchor="IANA.considerations">
904
905<section title="Status Code Registration" anchor="status.code.registration">
906<t>
907   The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
908   shall be updated with the registrations below:
909</t>
910<?BEGININC p5-range.iana-status-codes ?>
911<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
912<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
913   <ttcol>Value</ttcol>
914   <ttcol>Description</ttcol>
915   <ttcol>Reference</ttcol>
916   <c>206</c>
917   <c>Partial Content</c>
918   <c>
919      <xref target="status.206"/>
920   </c>
921   <c>416</c>
922   <c>Requested Range Not Satisfiable</c>
923   <c>
924      <xref target="status.416"/>
925   </c>
926</texttable>
927<!--(END)-->
928<?ENDINC p5-range.iana-status-codes ?>
929</section>
930
931<section title="Header Field Registration" anchor="header.field.registration">
932<t>
933   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
934   with the permanent registrations below (see <xref target="RFC3864"/>):
935</t>
936<?BEGININC p5-range.iana-headers ?>
937<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
938<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
939   <ttcol>Header Field Name</ttcol>
940   <ttcol>Protocol</ttcol>
941   <ttcol>Status</ttcol>
942   <ttcol>Reference</ttcol>
943
944   <c>Accept-Ranges</c>
945   <c>http</c>
946   <c>standard</c>
947   <c>
948      <xref target="header.accept-ranges"/>
949   </c>
950   <c>Content-Range</c>
951   <c>http</c>
952   <c>standard</c>
953   <c>
954      <xref target="header.content-range"/>
955   </c>
956   <c>If-Range</c>
957   <c>http</c>
958   <c>standard</c>
959   <c>
960      <xref target="header.if-range"/>
961   </c>
962   <c>Range</c>
963   <c>http</c>
964   <c>standard</c>
965   <c>
966      <xref target="header.range"/>
967   </c>
968</texttable>
969<!--(END)-->
970<?ENDINC p5-range.iana-headers ?>
971<t>
972   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
973</t>
974</section>
975
976<section title="Range Specifier Registration" anchor="range.specifier.registration">
977<t>
978  The registration procedure for HTTP Range Specifiers is defined by
979  <xref target="range.specifier.registry"/> of this document.
980</t>
981<t>
982   The HTTP Range Specifier Registry shall be created at <eref target="http://www.iana.org/assignments/http-range-specifiers"/>
983   and be populated with the registrations below:
984</t>
985<texttable align="left" suppress-title="true" anchor="iana.range.specifiers.table">
986   <ttcol>Range Specifier Name</ttcol>
987   <ttcol>Description</ttcol>
988   <ttcol>Reference</ttcol>
989
990   <c>bytes</c>
991   <c>a range of octets</c>
992   <c>(this specification)</c>
993</texttable>
994<t>
995   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
996</t>
997</section>
998</section>
999
1000<section title="Security Considerations" anchor="security.considerations">
1001<t>
1002   This section is meant to inform application developers, information
1003   providers, and users of the security limitations in HTTP/1.1 as
1004   described by this document. The discussion does not include
1005   definitive solutions to the problems revealed, though it does make
1006   some suggestions for reducing security risks.
1007</t>
1008<section title="Overlapping Ranges" anchor="overlapping.ranges">
1009<t>
1010   Range requests containing overlapping ranges may lead to the situation
1011   where a server is sending far more data than the size of the complete
1012   resource representation.
1013</t>
1014</section>
1015</section>
1016
1017<section title="Acknowledgments" anchor="acks">
1018<t>
1019  See &acks;.
1020</t>
1021</section>
1022</middle>
1023<back>
1024
1025<references title="Normative References">
1026
1027<reference anchor="Part1">
1028  <front>
1029    <title abbrev="HTTP/1.1">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
1030    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1031      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1032      <address><email>fielding@gbiv.com</email></address>
1033    </author>
1034    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1035      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1036      <address><email>jg@freedesktop.org</email></address>
1037    </author>
1038    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1039      <organization abbrev="HP">Hewlett-Packard Company</organization>
1040      <address><email>JeffMogul@acm.org</email></address>
1041    </author>
1042    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1043      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1044      <address><email>henrikn@microsoft.com</email></address>
1045    </author>
1046    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1047      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1048      <address><email>LMM@acm.org</email></address>
1049    </author>
1050    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1051      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1052      <address><email>paulle@microsoft.com</email></address>
1053    </author>
1054    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1055      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1056      <address><email>timbl@w3.org</email></address>
1057    </author>
1058    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1059      <organization abbrev="W3C">World Wide Web Consortium</organization>
1060      <address><email>ylafon@w3.org</email></address>
1061    </author>
1062    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1063      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1064      <address><email>julian.reschke@greenbytes.de</email></address>
1065    </author>
1066    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1067  </front>
1068  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1069  <x:source href="p1-messaging.xml" basename="p1-messaging"/>
1070</reference>
1071
1072<reference anchor="Part4">
1073  <front>
1074    <title abbrev="HTTP/1.1">HTTP/1.1, part 4: Conditional Requests</title>
1075    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1076      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1077      <address><email>fielding@gbiv.com</email></address>
1078    </author>
1079    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1080      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1081      <address><email>jg@freedesktop.org</email></address>
1082    </author>
1083    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1084      <organization abbrev="HP">Hewlett-Packard Company</organization>
1085      <address><email>JeffMogul@acm.org</email></address>
1086    </author>
1087    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1088      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1089      <address><email>henrikn@microsoft.com</email></address>
1090    </author>
1091    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1092      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1093      <address><email>LMM@acm.org</email></address>
1094    </author>
1095    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1096      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1097      <address><email>paulle@microsoft.com</email></address>
1098    </author>
1099    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1100      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1101      <address><email>timbl@w3.org</email></address>
1102    </author>
1103    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1104      <organization abbrev="W3C">World Wide Web Consortium</organization>
1105      <address><email>ylafon@w3.org</email></address>
1106    </author>
1107    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1108      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1109      <address><email>julian.reschke@greenbytes.de</email></address>
1110    </author>
1111    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1112  </front>
1113  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1114  <x:source href="p4-conditional.xml" basename="p4-conditional"/>
1115</reference>
1116
1117<reference anchor="RFC2046">
1118  <front>
1119    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1120    <author initials="N." surname="Freed" fullname="Ned Freed">
1121      <organization>Innosoft International, Inc.</organization>
1122      <address><email>ned@innosoft.com</email></address>
1123    </author>
1124    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1125      <organization>First Virtual Holdings</organization>
1126      <address><email>nsb@nsb.fv.com</email></address>
1127    </author>
1128    <date month="November" year="1996"/>
1129  </front>
1130  <seriesInfo name="RFC" value="2046"/>
1131</reference>
1132
1133<reference anchor="RFC2119">
1134  <front>
1135    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1136    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1137      <organization>Harvard University</organization>
1138      <address><email>sob@harvard.edu</email></address>
1139    </author>
1140    <date month="March" year="1997"/>
1141  </front>
1142  <seriesInfo name="BCP" value="14"/>
1143  <seriesInfo name="RFC" value="2119"/>
1144</reference>
1145
1146<reference anchor="RFC5234">
1147  <front>
1148    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
1149    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
1150      <organization>Brandenburg InternetWorking</organization>
1151      <address>
1152        <email>dcrocker@bbiw.net</email>
1153      </address> 
1154    </author>
1155    <author initials="P." surname="Overell" fullname="Paul Overell">
1156      <organization>THUS plc.</organization>
1157      <address>
1158        <email>paul.overell@thus.net</email>
1159      </address>
1160    </author>
1161    <date month="January" year="2008"/>
1162  </front>
1163  <seriesInfo name="STD" value="68"/>
1164  <seriesInfo name="RFC" value="5234"/>
1165</reference>
1166
1167</references>
1168
1169<references title="Informative References">
1170
1171<reference anchor="RFC2616">
1172  <front>
1173    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
1174    <author initials="R." surname="Fielding" fullname="R. Fielding">
1175      <organization>University of California, Irvine</organization>
1176      <address><email>fielding@ics.uci.edu</email></address>
1177    </author>
1178    <author initials="J." surname="Gettys" fullname="J. Gettys">
1179      <organization>W3C</organization>
1180      <address><email>jg@w3.org</email></address>
1181    </author>
1182    <author initials="J." surname="Mogul" fullname="J. Mogul">
1183      <organization>Compaq Computer Corporation</organization>
1184      <address><email>mogul@wrl.dec.com</email></address>
1185    </author>
1186    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
1187      <organization>MIT Laboratory for Computer Science</organization>
1188      <address><email>frystyk@w3.org</email></address>
1189    </author>
1190    <author initials="L." surname="Masinter" fullname="L. Masinter">
1191      <organization>Xerox Corporation</organization>
1192      <address><email>masinter@parc.xerox.com</email></address>
1193    </author>
1194    <author initials="P." surname="Leach" fullname="P. Leach">
1195      <organization>Microsoft Corporation</organization>
1196      <address><email>paulle@microsoft.com</email></address>
1197    </author>
1198    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
1199      <organization>W3C</organization>
1200      <address><email>timbl@w3.org</email></address>
1201    </author>
1202    <date month="June" year="1999"/>
1203  </front>
1204  <seriesInfo name="RFC" value="2616"/>
1205</reference>
1206
1207<reference anchor='RFC3864'>
1208  <front>
1209    <title>Registration Procedures for Message Header Fields</title>
1210    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
1211      <organization>Nine by Nine</organization>
1212      <address><email>GK-IETF@ninebynine.org</email></address>
1213    </author>
1214    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
1215      <organization>BEA Systems</organization>
1216      <address><email>mnot@pobox.com</email></address>
1217    </author>
1218    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
1219      <organization>HP Labs</organization>
1220      <address><email>JeffMogul@acm.org</email></address>
1221    </author>
1222    <date year='2004' month='September' />
1223  </front>
1224  <seriesInfo name='BCP' value='90' />
1225  <seriesInfo name='RFC' value='3864' />
1226</reference>
1227
1228<reference anchor="RFC4288">
1229  <front>
1230    <title>Media Type Specifications and Registration Procedures</title>
1231    <author initials="N." surname="Freed" fullname="N. Freed">
1232      <organization>Sun Microsystems</organization>
1233      <address>
1234        <email>ned.freed@mrochek.com</email>
1235      </address>
1236    </author>
1237    <author initials="J." surname="Klensin" fullname="J. Klensin">
1238      <address>
1239        <email>klensin+ietf@jck.com</email>
1240      </address>
1241    </author>
1242    <date year="2005" month="December"/>
1243  </front>
1244  <seriesInfo name="BCP" value="13"/>
1245  <seriesInfo name="RFC" value="4288"/>
1246</reference>
1247
1248<reference anchor='RFC5226'>
1249  <front>
1250    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
1251    <author initials='T.' surname='Narten' fullname='T. Narten'>
1252      <organization>IBM</organization>
1253      <address><email>narten@us.ibm.com</email></address>
1254    </author>
1255    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
1256      <organization>Google</organization>
1257      <address><email>Harald@Alvestrand.no</email></address>
1258    </author>
1259    <date year='2008' month='May' />
1260  </front>
1261  <seriesInfo name='BCP' value='26' />
1262  <seriesInfo name='RFC' value='5226' />
1263</reference>
1264
1265</references>
1266
1267<section title="Internet Media Type multipart/byteranges" anchor="internet.media.type.multipart.byteranges">
1268<iref item="Media Type" subitem="multipart/byteranges" primary="true"/>
1269<iref item="multipart/byteranges Media Type" primary="true"/>
1270<t>
1271   When an HTTP 206 (Partial Content) response message includes the
1272   content of multiple ranges (a response to a request for multiple
1273   non-overlapping ranges), these are transmitted as a multipart
1274   message-body (<xref target="RFC2046" x:fmt="," x:sec="5.1"/>). The media type for this purpose is called
1275   "multipart/byteranges".  The following is to be registered with IANA <xref target="RFC4288"/>.
1276</t>
1277<x:note>
1278  <t>
1279    <x:h>Note:</x:h> Despite the name "multipart/byteranges" is not limited to the byte ranges only.
1280  </t>
1281</x:note>
1282<t>
1283   The multipart/byteranges media type includes one or more parts, each
1284   with its own Content-Type and Content-Range fields. The required
1285   boundary parameter specifies the boundary string used to separate
1286   each body-part.
1287</t>
1288<t>
1289  <list style="hanging" x:indent="12em">
1290    <t hangText="Type name:">
1291      multipart
1292    </t>
1293    <t hangText="Subtype name:">
1294      byteranges
1295    </t>
1296    <t hangText="Required parameters:">
1297      boundary
1298    </t>
1299    <t hangText="Optional parameters:">
1300      none
1301    </t>
1302    <t hangText="Encoding considerations:">
1303      only "7bit", "8bit", or "binary" are permitted
1304    </t>
1305    <t hangText="Security considerations:">
1306      none
1307    </t>
1308    <t hangText="Interoperability considerations:">
1309      none
1310    </t>
1311    <t hangText="Published specification:">
1312      This specification (see <xref target="internet.media.type.multipart.byteranges"/>).
1313    </t>
1314    <t hangText="Applications that use this media type:">
1315    </t>
1316    <t hangText="Additional information:">
1317      <list style="hanging">
1318        <t hangText="Magic number(s):">none</t>
1319        <t hangText="File extension(s):">none</t>
1320        <t hangText="Macintosh file type code(s):">none</t>
1321      </list>
1322    </t>
1323    <t hangText="Person and email address to contact for further information:">
1324      See Authors Section.
1325    </t>
1326    <t hangText="Intended usage:">
1327      COMMON
1328    </t>
1329    <t hangText="Restrictions on usage:">
1330      none
1331    </t>
1332    <t hangText="Author/Change controller:">
1333      IESG
1334    </t>
1335  </list>
1336</t>
1337<figure><preamble>
1338   For example:
1339</preamble><artwork type="example">
1340  HTTP/1.1 206 Partial Content
1341  Date: Wed, 15 Nov 1995 06:25:24 GMT
1342  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1343  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1344 
1345  --THIS_STRING_SEPARATES
1346  Content-type: application/pdf
1347  Content-range: bytes 500-999/8000
1348 
1349  ...the first range...
1350  --THIS_STRING_SEPARATES
1351  Content-type: application/pdf
1352  Content-range: bytes 7000-7999/8000
1353 
1354  ...the second range
1355  --THIS_STRING_SEPARATES--
1356</artwork></figure>
1357<figure><preamble>
1358   Other example:
1359</preamble>
1360<artwork type="example">
1361  HTTP/1.1 206 Partial Content
1362  Date: Tue, 14 Nov 1995 06:25:24 GMT
1363  Last-Modified: Tue, 14 July 04:58:08 GMT
1364  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1365 
1366  --THIS_STRING_SEPARATES
1367  Content-type: video/example
1368  Content-range: exampleunit 1.2-4.3/25
1369 
1370  ...the first range...
1371  --THIS_STRING_SEPARATES
1372  Content-type: video/example
1373  Content-range: exampleunit 11.2-14.3/25
1374 
1375  ...the second range
1376  --THIS_STRING_SEPARATES--
1377</artwork>
1378</figure>
1379<t>
1380      Notes:
1381  <list style="numbers">
1382      <t>Additional CRLFs &MAY; precede the first boundary string in the body.</t>
1383
1384      <t>Although <xref target="RFC2046"/> permits the boundary string to be
1385         quoted, some existing implementations handle a quoted boundary
1386         string incorrectly.</t>
1387
1388      <t>A number of browsers and servers were coded to an early draft
1389         of the byteranges specification to use a media type of
1390         multipart/x-byteranges<iref item="multipart/x-byteranges Media Type"/><iref item="Media Type" subitem="multipart/x-byteranges"/>, which is almost, but not quite
1391         compatible with the version documented in HTTP/1.1.</t>
1392  </list>
1393</t>
1394</section>
1395
1396<section title="Compatibility with Previous Versions" anchor="compatibility">
1397<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
1398<t>
1399  Clarify that it is not ok to use a weak validator in a 206 response.
1400  (<xref target="status.206"/>)
1401</t>
1402<t>
1403  Change ABNF productions for header fields to only define the field value.
1404  (<xref target="header.fields"/>)
1405</t>
1406<t>
1407  Clarify that multipart/byteranges can consist of a single part.
1408  (<xref target="internet.media.type.multipart.byteranges"/>)
1409</t>
1410</section>
1411
1412</section>
1413
1414<?BEGININC p5-range.abnf-appendix ?>
1415<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
1416<figure>
1417<artwork type="abnf" name="p5-range.parsed-abnf">
1418<x:ref>Accept-Ranges</x:ref> = acceptable-ranges
1419
1420<x:ref>Content-Range</x:ref> = content-range-spec
1421
1422<x:ref>HTTP-date</x:ref> = &lt;HTTP-date, defined in [Part1], Section 6.1&gt;
1423
1424<x:ref>If-Range</x:ref> = entity-tag / HTTP-date
1425
1426<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 1.2.2&gt;
1427
1428<x:ref>Range</x:ref> = byte-ranges-specifier / other-ranges-specifier
1429
1430<x:ref>acceptable-ranges</x:ref> = ( *( "," OWS ) range-unit *( OWS "," [ OWS
1431 range-unit ] ) ) / "none"
1432
1433<x:ref>byte-content-range-spec</x:ref> = bytes-unit SP byte-range-resp-spec "/" (
1434 instance-length / "*" )
1435<x:ref>byte-range-resp-spec</x:ref> = ( first-byte-pos "-" last-byte-pos ) / "*"
1436<x:ref>byte-range-set</x:ref> = ( *( "," OWS ) byte-range-spec ) / (
1437 suffix-byte-range-spec *( OWS "," [ ( OWS byte-range-spec ) /
1438 suffix-byte-range-spec ] ) )
1439<x:ref>byte-range-spec</x:ref> = first-byte-pos "-" [ last-byte-pos ]
1440<x:ref>byte-ranges-specifier</x:ref> = bytes-unit "=" byte-range-set
1441<x:ref>bytes-unit</x:ref> = "bytes"
1442
1443<x:ref>content-range-spec</x:ref> = byte-content-range-spec /
1444 other-content-range-spec
1445
1446<x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in [Part4], Section 2.3&gt;
1447
1448<x:ref>first-byte-pos</x:ref> = 1*DIGIT
1449
1450<x:ref>instance-length</x:ref> = 1*DIGIT
1451
1452<x:ref>last-byte-pos</x:ref> = 1*DIGIT
1453
1454<x:ref>other-content-range-spec</x:ref> = other-range-unit SP other-range-resp-spec
1455<x:ref>other-range-resp-spec</x:ref> = *CHAR
1456<x:ref>other-range-set</x:ref> = 1*CHAR
1457<x:ref>other-range-unit</x:ref> = token
1458<x:ref>other-ranges-specifier</x:ref> = other-range-unit "=" other-range-set
1459
1460<x:ref>range-unit</x:ref> = bytes-unit / other-range-unit
1461
1462<x:ref>suffix-byte-range-spec</x:ref> = "-" suffix-length
1463<x:ref>suffix-length</x:ref> = 1*DIGIT
1464
1465<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 1.2.2&gt;
1466</artwork>
1467</figure>
1468<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
1469; Accept-Ranges defined but not used
1470; Content-Range defined but not used
1471; If-Range defined but not used
1472; Range defined but not used
1473</artwork></figure></section>
1474<?ENDINC p5-range.abnf-appendix ?>
1475
1476
1477<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
1478
1479<section title="Since RFC 2616">
1480<t>
1481  Extracted relevant partitions from <xref target="RFC2616"/>.
1482</t>
1483</section>
1484
1485<section title="Since draft-ietf-httpbis-p5-range-00">
1486<t>
1487  Closed issues:
1488  <list style="symbols"> 
1489    <t>
1490      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/18"/>:
1491      "Cache validators in 206 responses"
1492      (<eref target="http://purl.org/NET/http-errata#ifrange206"/>)
1493    </t>
1494    <t>
1495      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
1496      "Normative and Informative references"
1497    </t>
1498    <t>
1499      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
1500      "Normative up-to-date references"
1501    </t>
1502  </list>
1503</t>
1504</section>
1505
1506<section title="Since draft-ietf-httpbis-p5-range-01">
1507<t>
1508  Closed issues:
1509  <list style="symbols"> 
1510    <t>
1511      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
1512      "Updating to RFC4288"
1513    </t>
1514  </list>
1515</t>
1516<t>
1517  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1518  <list style="symbols"> 
1519    <t>
1520      Add explicit references to BNF syntax and rules imported from other parts of the specification.
1521    </t>
1522  </list>
1523</t>
1524</section>
1525
1526<section title="Since draft-ietf-httpbis-p5-range-02" anchor="changes.since.02">
1527<t>
1528  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
1529  <list style="symbols"> 
1530    <t>
1531      Reference RFC 3984, and update header field registrations for headers defined
1532      in this document.
1533    </t>
1534  </list>
1535</t>
1536</section>
1537
1538<section title="Since draft-ietf-httpbis-p5-range-03" anchor="changes.since.03">
1539<t>
1540  None.
1541</t>
1542</section>
1543
1544<section title="Since draft-ietf-httpbis-p5-range-04" anchor="changes.since.04">
1545<t>
1546  Closed issues:
1547  <list style="symbols"> 
1548    <t>
1549      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/133"/>:
1550      "multipart/byteranges minimum number of parts"
1551    </t>
1552  </list>
1553</t>
1554<t>
1555  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1556  <list style="symbols"> 
1557    <t>
1558      Use "/" instead of "|" for alternatives.
1559    </t>
1560    <t>
1561      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
1562      whitespace ("OWS") and required whitespace ("RWS").
1563    </t>
1564    <t>
1565      Rewrite ABNFs to spell out whitespace rules, factor out
1566      header field value format definitions.
1567    </t>
1568  </list>
1569</t>
1570</section>
1571
1572<section title="Since draft-ietf-httpbis-p5-range-05" anchor="changes.since.05">
1573<t>
1574  Closed issues:
1575  <list style="symbols"> 
1576    <t>
1577      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/142"/>:
1578      "State base for *-byte-pos and suffix-length"
1579    </t>
1580  </list>
1581</t>
1582<t>
1583  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1584  <list style="symbols"> 
1585    <t>
1586      Remove bias in favor of byte ranges; allow custom ranges in ABNF.
1587    </t>
1588  </list>
1589</t>
1590<t>
1591  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1592  <list style="symbols"> 
1593    <t>
1594      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
1595    </t>
1596  </list>
1597</t>
1598</section>
1599
1600<section title="Since draft-ietf-httpbis-p5-range-06" anchor="changes.since.06">
1601<t>
1602  Closed issues:
1603  <list style="symbols"> 
1604    <t>
1605      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/161"/>:
1606      "base for numeric protocol elements"
1607    </t>
1608  </list>
1609</t>
1610</section>
1611
1612<section title="Since draft-ietf-httpbis-p5-range-07" anchor="changes.since.07">
1613<t>
1614  Closed issues:
1615  <list style="symbols">
1616    <t>
1617      Fixed discrepancy in the If-Range definition about allowed validators.
1618    </t>
1619    <t>
1620      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/150" />: "multipart/byteranges for custom range units"
1621    </t>
1622    <t>
1623      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/151" />: "range unit missing from other-ranges-specifier in Range header"
1624    </t>
1625    <t>
1626      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/198"/>:
1627      "move IANA registrations for optional status codes"
1628    </t>
1629  </list>
1630</t>
1631</section>
1632
1633<section title="Since draft-ietf-httpbis-p5-range-08" anchor="changes.since.08">
1634<t>
1635  No significant changes.
1636</t>
1637</section>
1638
1639<section title="Since draft-ietf-httpbis-p5-range-09" anchor="changes.since.09">
1640<t>
1641 No significant changes.
1642</t>
1643</section>
1644
1645<section title="Since draft-ietf-httpbis-p5-range-10" anchor="changes.since.10">
1646<t>
1647  Closed issues:
1648  <list style="symbols"> 
1649    <t>
1650      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
1651      "Clarify 'Requested Variant'"
1652    </t>
1653    <t>
1654      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
1655      "Clarify entity / representation / variant terminology"
1656    </t>
1657    <t>
1658      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
1659      "consider removing the 'changes from 2068' sections"
1660    </t>
1661  </list>
1662</t>
1663<t>
1664  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1665  <list style="symbols"> 
1666    <t>
1667      Add IANA registry.
1668    </t>
1669  </list>
1670</t>
1671</section>
1672
1673<section title="Since draft-ietf-httpbis-p5-range-11" anchor="changes.since.11">
1674<t>
1675  Closed issues:
1676  <list style="symbols"> 
1677    <t>
1678      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/217"/>:
1679      "Caches can't be required to serve ranges"
1680    </t>
1681  </list>
1682</t>
1683</section>
1684
1685<section title="Since draft-ietf-httpbis-p5-range-12" anchor="changes.since.12">
1686<t>
1687  Closed issues:
1688  <list style="symbols"> 
1689    <t>
1690      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
1691      "Header Classification"
1692    </t>
1693  </list>
1694</t>
1695</section>
1696
1697<section title="Since draft-ietf-httpbis-p5-range-13" anchor="changes.since.13">
1698<t>
1699  Closed issues:
1700  <list style="symbols">
1701    <t>
1702      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
1703      "untangle ABNFs for header fields"
1704    </t>
1705  </list>
1706</t>
1707</section>
1708
1709<section title="Since draft-ietf-httpbis-p5-range-14" anchor="changes.since.14">
1710<t>
1711  None.
1712</t>
1713</section>
1714
1715<section title="Since draft-ietf-httpbis-p5-range-15" anchor="changes.since.15">
1716<t>
1717  Closed issues:
1718  <list style="symbols">
1719    <t>
1720      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/175"/>:
1721      "Security consideration: range flooding"
1722    </t>
1723  </list>
1724</t>
1725</section>
1726
1727</section>
1728
1729</back>
1730</rfc>
Note: See TracBrowser for help on using the repository browser.