source: draft-ietf-httpbis/latest/p5-range.xml @ 1708

Last change on this file since 1708 was 1708, checked in by julian.reschke@…, 7 years ago

Work-in-progress: hyperlink status codes definitions (for those defined in parts 4, 5, and 7)

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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 "July">
16  <!ENTITY ID-YEAR "2012">
17  <!ENTITY Note "<x:h xmlns:x='http://purl.org/net/xml2rfc/ext'>Note:</x:h>">
18  <!ENTITY architecture               "<xref target='Part1' x:rel='#architecture' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
19  <!ENTITY notation                   "<xref target='Part1' x:rel='#notation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
20  <!ENTITY abnf-extension             "<xref target='Part1' x:rel='#abnf.extension' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
21  <!ENTITY acks                       "<xref target='Part1' x:rel='#acks' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
22  <!ENTITY whitespace                 "<xref target='Part1' x:rel='#whitespace' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY field-components           "<xref target='Part1' x:rel='#field.components' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY http-date                  "<xref target='Part2' x:rel='#http.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY messaging                  "<xref target='Part1' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26  <!ENTITY entity-tags                "<xref target='Part4' x:rel='#header.etag' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
27  <!ENTITY weak-and-strong-validators "<xref target='Part4' x:rel='#weak.and.strong.validators' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
28  <!ENTITY lastmod-comparison         "<xref target='Part4' x:rel='#lastmod.comparison' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
29  <!ENTITY p6-heuristic               "<xref target='Part6' x:rel='#heuristic.freshness' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
30]>
31<?rfc toc="yes" ?>
32<?rfc symrefs="yes" ?>
33<?rfc sortrefs="yes" ?>
34<?rfc compact="yes"?>
35<?rfc subcompact="no" ?>
36<?rfc linkmailto="no" ?>
37<?rfc editing="no" ?>
38<?rfc comments="yes"?>
39<?rfc inline="yes"?>
40<?rfc rfcedstyle="yes"?>
41<?rfc-ext allow-markup-in-artwork="yes" ?>
42<?rfc-ext include-references-in-index="yes" ?>
43<rfc obsoletes="2616" category="std" x:maturity-level="proposed"
44     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p5-range-&ID-VERSION;"
45     xmlns:x='http://purl.org/net/xml2rfc/ext'>
46<x:link rel="prev" basename="p4-conditional"/>
47<x:link rel="next" basename="p6-cache"/>
48<x:feedback template="mailto:ietf-http-wg@w3.org?subject={docname},%20%22{section}%22&amp;body=&lt;{ref}&gt;:"/>
49<front>
50
51  <title abbrev="HTTP/1.1, Part 5">HTTP/1.1, part 5: Range Requests and Partial Responses</title>
52
53  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
54    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
55    <address>
56      <postal>
57        <street>345 Park Ave</street>
58        <city>San Jose</city>
59        <region>CA</region>
60        <code>95110</code>
61        <country>USA</country>
62      </postal>
63      <email>fielding@gbiv.com</email>
64      <uri>http://roy.gbiv.com/</uri>
65    </address>
66  </author>
67
68  <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
69    <organization abbrev="W3C">World Wide Web Consortium</organization>
70    <address>
71      <postal>
72        <street>W3C / ERCIM</street>
73        <street>2004, rte des Lucioles</street>
74        <city>Sophia-Antipolis</city>
75        <region>AM</region>
76        <code>06902</code>
77        <country>France</country>
78      </postal>
79      <email>ylafon@w3.org</email>
80      <uri>http://www.raubacapeu.net/people/yves/</uri>
81    </address>
82  </author>
83
84  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
85    <organization abbrev="greenbytes">greenbytes GmbH</organization>
86    <address>
87      <postal>
88        <street>Hafenweg 16</street>
89        <city>Muenster</city><region>NW</region><code>48155</code>
90        <country>Germany</country>
91      </postal>
92      <email>julian.reschke@greenbytes.de</email>
93      <uri>http://greenbytes.de/tech/webdav/</uri>
94    </address>
95  </author>
96
97  <date month="&ID-MONTH;" year="&ID-YEAR;"/>
98  <workgroup>HTTPbis Working Group</workgroup>
99
100<abstract>
101<t>
102   The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
103   distributed, collaborative, hypertext information systems. HTTP has been in
104   use by the World Wide Web global information initiative since 1990. This
105   document is Part 5 of the seven-part specification that defines the protocol
106   referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
107</t>
108<t>
109   Part 5 defines range requests and the rules for constructing and
110   combining responses to those requests.
111</t>
112</abstract>
113
114<note title="Editorial Note (To be removed by RFC Editor)">
115  <t>
116    Discussion of this draft ought to take place on the HTTPBIS working group
117    mailing list (ietf-http-wg@w3.org), which is archived at
118    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
119  </t>
120  <t>
121    The current issues list is at
122    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
123    documents (including fancy diffs) can be found at
124    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
125  </t>
126  <t>
127    The changes in this draft are summarized in <xref target="changes.since.19"/>.
128  </t>
129</note>
130</front>
131<middle>
132<section title="Introduction" anchor="introduction">
133<t>
134   HTTP clients often encounter interrupted data transfers as a result
135   of cancelled requests or dropped connections.  When a client has stored
136   a partial representation, it is desirable to request the remainder
137   of that representation in a subsequent request rather than transfer
138   the entire representation.
139   There are also a number of Web applications that benefit from being
140   able to request only a subset of a larger representation, such as a
141   single page of a very large document or only part of an image to be
142   rendered by a device with limited local storage.
143</t>
144<t>
145   This document defines HTTP/1.1 range requests,
146   partial responses, and the multipart/byteranges media type.
147   The protocol for range requests is an &OPTIONAL; feature of HTTP,
148   designed so resources or recipients that do not implement this feature
149   can respond as if it is a normal GET request without impacting
150   interoperability.  Partial responses are indicated by a distinct status
151   code to not be mistaken for full responses by intermediate caches
152   that might not implement the feature.
153</t>
154<t>
155   Although the HTTP range request mechanism is designed to allow for
156   extensible range types, this specification only defines requests for
157   byte ranges.
158</t>
159
160<section title="Conformance and Error Handling" anchor="intro.conformance.and.error.handling">
161<t>
162   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
163   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
164   document are to be interpreted as described in <xref target="RFC2119"/>.
165</t>
166<t>
167   This document defines conformance criteria for several roles in HTTP
168   communication, including Senders, Recipients, Clients, Servers, User-Agents,
169   Origin Servers, Intermediaries, Proxies and Gateways. See &architecture;
170   for definitions of these terms.
171</t>
172<t>
173   An implementation is considered conformant if it complies with all of the
174   requirements associated with its role(s). Note that SHOULD-level requirements
175   are relevant here, unless one of the documented exceptions is applicable.
176</t>
177<t>
178   This document also uses ABNF to define valid protocol elements
179   (<xref target="notation"/>). In addition to the prose requirements placed
180   upon them, Senders &MUST-NOT; generate protocol elements that are invalid.
181</t>
182<t>
183   Unless noted otherwise, Recipients &MUST; be able to parse all protocol
184   elements matching the ABNF rules defined for them and &MAY; take steps to
185   recover a usable protocol element from an invalid construct. However, HTTP does not define
186   specific error handling mechanisms, except in cases where it has direct
187   impact on security. This is because different uses of the protocol require
188   different error handling strategies; for example, a Web browser might wish to
189   transparently recover from a response where the Location header field
190   doesn't parse according to the ABNF, whereby in a systems control protocol
191   using HTTP, this type of error recovery could lead to dangerous consequences.
192</t>
193</section>
194
195<section title="Syntax Notation" anchor="notation">
196  <x:anchor-alias value="ALPHA"/>
197  <x:anchor-alias value="CHAR"/>
198  <x:anchor-alias value="CR"/>
199  <x:anchor-alias value="DIGIT"/>
200  <x:anchor-alias value="LF"/>
201  <x:anchor-alias value="OCTET"/>
202  <x:anchor-alias value="SP"/>
203  <x:anchor-alias value="VCHAR"/>
204<t>
205   This specification uses the Augmented Backus-Naur Form (ABNF) notation
206   of <xref target="RFC5234"/> with the list rule extension defined in
207   &notation;<xref target="collected.abnf"/> shows the collected ABNF
208   with the list rule expanded.
209</t>
210<t>
211  The following core rules are included by
212  reference, as defined in <xref target="RFC5234" x:fmt="," x:sec="B.1"/>:
213  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
214  DIGIT (decimal 0-9), DQUOTE (double quote),
215  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
216  OCTET (any 8-bit sequence of data), SP (space), and
217  VCHAR (any visible US-ASCII character).
218</t>
219
220<t>
221  Note that all rules derived from <x:ref>token</x:ref> are to
222  be compared case-insensitively, like <x:ref>range-unit</x:ref> and
223  <x:ref>acceptable-ranges</x:ref>.
224</t>
225
226<section title="Core Rules" anchor="core.rules">
227  <x:anchor-alias value="token"/>
228  <x:anchor-alias value="OWS"/>
229  <x:anchor-alias value="HTTP-date"/>
230<t>
231  The core rules below are defined in <xref target="Part1"/> and
232  <xref target="Part2"/>:
233</t>
234<figure><artwork type="abnf2616">
235  <x:ref>OWS</x:ref>        = &lt;OWS, defined in &whitespace;&gt;
236  <x:ref>token</x:ref>      = &lt;token, defined in &field-components;&gt;
237  <x:ref>HTTP-date</x:ref>  = &lt;HTTP-date, defined in &http-date;&gt;
238</artwork></figure>
239</section>
240
241<section title="ABNF Rules defined in other Parts of the Specification" anchor="abnf.dependencies">
242  <x:anchor-alias value="entity-tag"/>
243<t>
244  The ABNF rules below are defined in other parts:
245</t>
246<figure><!--Part4--><artwork type="abnf2616">
247  <x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in &entity-tags;&gt;
248</artwork></figure>
249</section>
250
251</section>
252
253</section>
254
255
256<section title="Range Units" anchor="range.units">
257  <x:anchor-alias value="bytes-unit"/>
258  <x:anchor-alias value="other-range-unit"/>
259  <x:anchor-alias value="range-unit"/>
260<t>
261   HTTP/1.1 allows a client to request that only part (a range) of the
262   representation be included within the response. HTTP/1.1 uses range
263   units in the Range (<xref target="header.range"/>) and Content-Range (<xref target="header.content-range"/>)
264   header fields. A representation can be broken down into subranges according
265   to various structural units.
266</t>
267<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"/>
268  <x:ref>range-unit</x:ref>       = <x:ref>bytes-unit</x:ref> / <x:ref>other-range-unit</x:ref>
269  <x:ref>bytes-unit</x:ref>       = "bytes"
270  <x:ref>other-range-unit</x:ref> = <x:ref>token</x:ref>
271</artwork></figure>
272<t>
273  HTTP/1.1 has been designed to allow implementations of applications
274  that do not depend on knowledge of ranges. The only range unit defined
275  by HTTP/1.1 is "bytes". Additional specifiers can be defined as described
276  in <xref target="range.specifier.registry"/>.
277</t>
278<t>
279  If a range unit is not understood in a request, a server &MUST; ignore
280  the whole Range header field (<xref target="header.range"/>).
281  If a range unit is not understood in a response, an intermediary
282  &SHOULD; pass the response to the client; a client &MUST; fail.
283</t>
284
285<section title="Range Specifier Registry" anchor="range.specifier.registry">
286<t>
287   The HTTP Range Specifier Registry defines the name space for the range
288   specifier names.
289</t>
290<t>
291   Registrations &MUST; include the following fields:
292   <list style="symbols">
293     <t>Name</t>
294     <t>Description</t>
295     <t>Pointer to specification text</t>
296   </list>
297</t>
298<t>
299  Values to be added to this name space require IETF Review
300  (see <xref target="RFC5226" x:fmt="," x:sec="4.1"/>).
301</t>
302<t>
303   The registry itself is maintained at
304   <eref target="http://www.iana.org/assignments/http-range-specifiers"/>.
305</t>
306</section>
307
308</section>
309
310<section title="Status Code Definitions" anchor="status.code.definitions">
311<section title="206 Partial Content" anchor="status.206">
312  <iref primary="true" item="206 Partial Content (status code)" x:for-anchor=""/>
313  <iref primary="true" item="Status Codes" subitem="206 Partial Content" x:for-anchor=""/>
314  <x:anchor-alias value="206 (Partial Content)"/>
315<t>
316   The server has fulfilled the partial GET request for the resource.
317   The request &MUST; have included a Range header field (<xref target="header.range"/>)
318   indicating the desired range, and &MAY; have included an If-Range
319   header field (<xref target="header.if-range"/>) to make the request conditional.
320</t>
321<t>
322   The response &MUST; include the following header fields:
323  <list style="symbols">
324    <t>
325        Either a Content-Range header field (<xref target="header.content-range"/>) indicating
326        the range included with this response, or a multipart/byteranges
327        Content-Type including Content-Range fields for each part. If a
328        Content-Length header field is present in the response, its
329        value &MUST; match the actual number of octets transmitted in the
330        message body.
331    </t>
332    <t>
333        Date
334    </t>
335    <t>
336        Cache-Control, ETag, Expires, Content-Location and/or Vary, if
337        the header field would have been sent in a 200 response to the
338        same request
339    </t>
340  </list>
341</t>
342<t>
343   If a 206 is sent in response to a request with an If-Range header field, it
344   &SHOULD-NOT; include other representation header fields. Otherwise, the response
345   &MUST; include all of the representation header fields that would have been returned
346   with a 200 (OK) response to the same request.
347</t>
348<t>
349   Caches &MAY; use a heuristic (see &p6-heuristic;) to determine
350   freshness for 206 responses.
351</t>
352</section>
353
354<section title="416 Requested Range Not Satisfiable" anchor="status.416">
355  <iref primary="true" item="416 Requested Range Not Satisfiable (status code)" x:for-anchor=""/>
356  <iref primary="true" item="Status Codes" subitem="416 Requested Range Not Satisfiable" x:for-anchor=""/>
357  <x:anchor-alias value="416 (Requested Range Not Satisfiable)"/>
358<t>
359   A server &SHOULD; return a response with this status code if a request
360   included a Range header field (<xref target="header.range"/>), and none of
361   the ranges-specifier values in this field overlap the current extent
362   of the selected resource, and the request did not include an If-Range
363   header field (<xref target="header.if-range"/>). (For byte-ranges,
364   this means that the first-byte-pos of all of the byte-range-spec values were
365   greater than the current length of the selected resource.)
366</t>
367<t>
368   When this status code is returned for a byte-range request, the
369   response &SHOULD; include a Content-Range header field
370   specifying the current length of the representation (see <xref target="header.content-range"/>).
371   This response &MUST-NOT; use the multipart/byteranges content-type. For example,
372</t>
373<figure><artwork type="message/http; msgtype=&#34;response&#34;" x:indent-with="  ">
374HTTP/1.1 416 Requested Range Not Satisfiable
375Date: Mon, 20 Jan 2012 15:41:54 GMT
376Content-Range: bytes */47022
377Content-Type: image/gif
378</artwork></figure>
379<x:note>
380  <t>
381    &Note; Clients cannot depend on servers to send a <x:ref>416 (Requested
382    Range Not Satisfiable)</x:ref> response instead of a 200 (OK) response for
383    an unsatisfiable Range header field, since not all servers
384    implement this header field.
385  </t>
386</x:note>
387</section>
388</section>
389
390<section title="Responses to a Range Request">
391<section title="Response to a Single and Multiple Ranges Request">
392<t>
393   When an HTTP message includes the content of a single range (for
394   example, a response to a request for a single range, or to a request
395   for a set of ranges that overlap without any holes), this content is
396   transmitted with a Content-Range header field, and a Content-Length header
397   field showing the number of bytes actually transferred. For example,
398</t>
399<figure><artwork type="message/http; msgtype=&#34;response&#34;" x:indent-with="  ">
400HTTP/1.1 206 Partial Content
401Date: Wed, 15 Nov 1995 06:25:24 GMT
402Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
403Content-Range: bytes 21010-47021/47022
404Content-Length: 26012
405Content-Type: image/gif
406</artwork></figure>
407<t>
408   When an HTTP message includes the content of multiple ranges (for
409   example, a response to a request for multiple non-overlapping
410   ranges), these are transmitted as a multipart message. The multipart
411   media type used for this purpose is "multipart/byteranges" as defined
412   in <xref target="internet.media.type.multipart.byteranges"/>.
413</t>
414<t>
415   A server &MAY; combine requested ranges when those ranges are overlapping
416   (see <xref target="overlapping.ranges"/>).
417</t>
418<t>
419   A response to a request for a single range &MUST-NOT; be sent using the
420   multipart/byteranges media type.  A response to a request for
421   multiple ranges, whose result is a single range, &MAY; be sent as a
422   multipart/byteranges media type with one part. A client that cannot
423   decode a multipart/byteranges message &MUST-NOT; ask for multiple
424   ranges in a single request.
425</t>
426<t>
427   When a client asks for multiple ranges in one request, the
428   server &SHOULD; return them in the order that they appeared in the
429   request.
430</t>
431</section>
432
433<section title="Combining Ranges" anchor="combining.byte.ranges">
434<t>
435   A response might transfer only a subrange of a representation if the
436   connection closed prematurely or if the request used one or more Range
437   specifications.  After several such transfers, a client might have
438   received several ranges of the same representation.  These ranges can only
439   be safely combined if they all have in common the same strong validator,
440   where "strong validator" is defined to be either an entity-tag that is
441   not marked as weak (&entity-tags;) or, if no entity-tag is provided, a
442   Last-Modified value that is strong in the sense defined by
443   &lastmod-comparison;.
444</t>
445<t>
446   When a client receives an incomplete 200 (OK) or <x:ref>206 (Partial Content)</x:ref>
447   response and already has one or more stored responses for the same method
448   and effective request URI, all of the stored responses with the same
449   strong validator &MAY; be combined with the partial content in this new
450   response.  If none of the stored responses contain the same strong
451   validator, then this new response corresponds to a new representation
452   and &MUST-NOT; be combined with the existing stored responses.
453</t>
454<t>
455   If the new response is an incomplete 200 (OK) response, then the header
456   fields of that new response are used for any combined response and replace
457   those of the matching stored responses.
458</t>
459<t>
460   If the new response is a <x:ref>206 (Partial Content)</x:ref> response and at least one
461   of the matching stored responses is a 200 (OK), then the combined response
462   header fields consist of the most recent 200 response's header fields.
463   If all of the matching stored responses are 206 responses, then the
464   stored response with the most header fields is used as the source of
465   header fields for the combined response, except that the client &MUST;
466   use other header fields provided in the new response, aside from
467   Content-Range, to replace all instances of the corresponding header
468   fields in the stored response.
469</t>
470<t>
471   The combined response message body consists of the union of partial
472   content ranges in the new response and each of the selected responses.
473   If the union consists of the entire range of the representation, then the
474   combined response &MUST; be recorded as a complete 200 (OK) response
475   with a Content-Length header field that reflects the complete length.
476   Otherwise, the combined response(s) &MUST; include a Content-Range
477   header field describing the included range(s) and be recorded as
478   incomplete.  If the union consists of a discontinuous range of the
479   representation, then the client &MAY; store it as either a multipart range
480   response or as multiple 206 responses with one continuous range each.
481</t>
482</section>
483</section>
484
485<section title="Header Field Definitions" anchor="header.field.definitions">
486<t>
487   This section defines the syntax and semantics of HTTP/1.1 header fields
488   related to range requests and partial responses.
489</t>
490
491<section title="Accept-Ranges" anchor="header.accept-ranges">
492  <iref primary="true" item="Accept-Ranges header field" x:for-anchor=""/>
493  <iref primary="true" item="Header Fields" subitem="Accept-Ranges" x:for-anchor=""/>
494  <x:anchor-alias value="Accept-Ranges"/>
495  <x:anchor-alias value="acceptable-ranges"/>
496<t>
497   The "Accept-Ranges" header field allows a resource to indicate
498   its acceptance of range requests.
499</t>
500<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Ranges"/><iref primary="true" item="Grammar" subitem="acceptable-ranges"/>
501  <x:ref>Accept-Ranges</x:ref>     = <x:ref>acceptable-ranges</x:ref>
502  <x:ref>acceptable-ranges</x:ref> = 1#<x:ref>range-unit</x:ref> / "none"
503</artwork></figure>
504<t>
505      Origin servers that accept byte-range requests &MAY; send
506</t>
507<figure><artwork type="example">
508  Accept-Ranges: bytes
509</artwork></figure>
510<t>
511      but are not required to do so. Clients &MAY; generate range
512      requests without having received this header field for the resource
513      involved. Range units are defined in <xref target="range.units"/>.
514</t>
515<t>
516      Servers that do not accept any kind of range request for a
517      resource &MAY; send
518</t>
519<figure><artwork type="example">
520  Accept-Ranges: none
521</artwork></figure>
522<t>
523      to advise the client not to attempt a range request.
524</t>
525</section>
526
527<section title="Content-Range" anchor="header.content-range">
528  <iref primary="true" item="Content-Range header field" x:for-anchor=""/>
529  <iref primary="true" item="Header Fields" subitem="Content-Range" x:for-anchor=""/>
530  <x:anchor-alias value="byte-content-range-spec"/>
531  <x:anchor-alias value="byte-range-resp-spec"/>
532  <x:anchor-alias value="Content-Range"/>
533  <x:anchor-alias value="instance-length"/>
534  <x:anchor-alias value="other-content-range-spec"/>
535  <x:anchor-alias value="other-range-resp-spec"/>
536<t>
537   The "Content-Range" header field is sent with a partial representation to
538   specify where in the full representation the payload body is intended to be
539   applied.
540</t>
541<t>   
542   Range units are defined in <xref target="range.units"/>.
543</t>
544<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Range"/><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"/>
545  <x:ref>Content-Range</x:ref>           = <x:ref>byte-content-range-spec</x:ref>
546                          / <x:ref>other-content-range-spec</x:ref>
547                         
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 <x:ref>416 (Requested Range Not
583   Satisfiable)</x:ref> &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 <x:ref>206 (Partial Content)</x:ref>
586   &MUST-NOT; include a Content-Range field with a byte-range-resp-spec of "*".
587</t>
588<t>
589  The "Content-Range" header field has no meaning for status codes that do not
590  explicitly describe its semantic. Currently, only status codes
591  <x:ref>206 (Partial Content)</x:ref> and <x:ref>416 (Requested Range Not Satisfiable)</x:ref> describe
592  the meaning of this header field.
593</t>
594<t>
595   Examples of byte-content-range-spec values, assuming that the representation
596   contains a total of 1234 bytes:
597   <list style="symbols">
598      <t>
599        The first 500 bytes:
600<figure><artwork type="example" x:indent-with="   ">
601  bytes 0-499/1234
602</artwork></figure>
603      </t>   
604      <t>
605        The second 500 bytes:
606<figure><artwork type="example" x:indent-with="   ">
607  bytes 500-999/1234
608</artwork></figure>
609      </t>   
610      <t>
611        All except for the first 500 bytes:
612<figure><artwork type="example" x:indent-with="   ">
613  bytes 500-1233/1234
614</artwork></figure>
615      </t>   
616      <t>
617        The last 500 bytes:
618<figure><artwork type="example" x:indent-with="   ">
619  bytes 734-1233/1234
620</artwork></figure>
621      </t>   
622   </list>
623</t>
624<t>
625   If the server ignores a byte-range-spec (for example if it is
626   syntactically invalid, or if it might be seen as a denial-of-service
627   attack), the server &SHOULD; treat the request as if the invalid Range
628   header field did not exist. (Normally, this means return a 200
629   response containing the full representation).
630</t>
631</section>
632
633<section title="If-Range" anchor="header.if-range">
634  <iref primary="true" item="If-Range header field" x:for-anchor=""/>
635  <iref primary="true" item="Header Fields" subitem="If-Range" x:for-anchor=""/>
636  <x:anchor-alias value="If-Range"/>
637<t>
638   If a client has a partial copy of a representation and wishes
639   to have an up-to-date copy of the entire representation, it
640   could use the Range header field with a conditional GET (using
641   either or both of If-Unmodified-Since and If-Match.) However, if the
642   condition fails because the representation has been modified, the client
643   would then have to make a second request to obtain the entire current
644   representation.
645</t>
646<t>
647   The "If-Range" header field allows a client to "short-circuit" the second
648   request. Informally, its meaning is "if the representation is unchanged, send
649   me the part(s) that I am missing; otherwise, send me the entire new
650   representation".
651</t>
652<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="If-Range"/>
653  <x:ref>If-Range</x:ref> = <x:ref>entity-tag</x:ref> / <x:ref>HTTP-date</x:ref>
654</artwork></figure>
655<t>
656   Clients &MUST-NOT; use an entity-tag marked as weak in an If-Range
657   field value and &MUST-NOT; use a Last-Modified date in an If-Range
658   field value unless it has no entity-tag for the representation and
659   the Last-Modified date it does have for the representation is strong
660   in the sense defined by &lastmod-comparison;.
661</t>
662<t>
663   A server that evaluates a conditional range request that is applicable
664   to one of its representations &MUST; evaluate the condition as false if
665   the entity-tag used as a validator is marked as weak or, when an HTTP-date
666   is used as the validator, if the date value is not strong in the sense
667   defined by &lastmod-comparison;. (A server can distinguish between a
668   valid HTTP-date and any form of entity-tag by examining the first
669   two characters.)
670</t>
671<t>
672   The If-Range header field &SHOULD; only be sent by clients together with
673   a Range header field.  The If-Range header field &MUST; be ignored if it
674   is received in a request that does not include a Range header field.
675   The If-Range header field &MUST; be ignored by a server that does not
676   support the sub-range operation.
677</t>
678<t>
679   If the validator given in the If-Range header field matches the current
680   validator for the selected representation of the target resource, then
681   the server &SHOULD; send the specified sub-range of the representation
682   using a <x:ref>206 (Partial Content)</x:ref> response. If the validator does not match,
683   then the server &SHOULD; send the entire representation using a 200 (OK)
684   response.
685</t>
686</section>
687
688<section title="Range" anchor="header.range">
689  <iref primary="true" item="Range header field" x:for-anchor=""/>
690  <iref primary="true" item="Header Fields" subitem="Range" x:for-anchor=""/>
691
692<section title="Byte Ranges" anchor="byte.ranges">
693<t>
694   Since all HTTP representations are transferred as sequences
695   of bytes, the concept of a byte range is meaningful for any HTTP
696   representation. (However, not all clients and servers need to support byte-range
697   operations.)
698</t>
699<t>
700   Byte range specifications in HTTP apply to the sequence of bytes in
701   the representation body (not necessarily the same as the message body).
702</t>
703<t anchor="rule.ranges-specifier">
704  <x:anchor-alias value="byte-range-set"/>
705  <x:anchor-alias value="byte-range-spec"/>
706  <x:anchor-alias value="byte-ranges-specifier"/>
707  <x:anchor-alias value="first-byte-pos"/>
708  <x:anchor-alias value="last-byte-pos"/>
709  <x:anchor-alias value="ranges-specifier"/>
710  <x:anchor-alias value="suffix-byte-range-spec"/>
711  <x:anchor-alias value="suffix-length"/>
712
713   A byte range operation &MAY; specify a single range of bytes, or a set
714   of ranges within a single representation.
715</t>
716<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"/>
717  <x:ref>byte-ranges-specifier</x:ref> = <x:ref>bytes-unit</x:ref> "=" <x:ref>byte-range-set</x:ref>
718  <x:ref>byte-range-set</x:ref>  = 1#( <x:ref>byte-range-spec</x:ref> / <x:ref>suffix-byte-range-spec</x:ref> )
719  <x:ref>byte-range-spec</x:ref> = <x:ref>first-byte-pos</x:ref> "-" [ <x:ref>last-byte-pos</x:ref> ]
720  <x:ref>first-byte-pos</x:ref>  = 1*<x:ref>DIGIT</x:ref>
721  <x:ref>last-byte-pos</x:ref>   = 1*<x:ref>DIGIT</x:ref>
722</artwork></figure>
723<t>
724   The first-byte-pos value in a byte-range-spec gives the byte-offset
725   of the first byte in a range. The last-byte-pos value gives the
726   byte-offset of the last byte in the range; that is, the byte
727   positions specified are inclusive. Byte offsets start at zero.
728</t>
729<t>
730   If the last-byte-pos value is present, it &MUST; be greater than or
731   equal to the first-byte-pos in that byte-range-spec, or the byte-range-spec
732   is syntactically invalid. The recipient of a byte-range-set
733   that includes one or more syntactically invalid byte-range-spec
734   values &MUST; ignore the header field that includes that byte-range-set.
735</t>
736<t>
737   If the last-byte-pos value is absent, or if the value is greater than
738   or equal to the current length of the representation body, last-byte-pos is
739   taken to be equal to one less than the current length of the representation
740   in bytes.
741</t>
742<t>
743   By its choice of last-byte-pos, a client can limit the number of
744   bytes retrieved without knowing the size of the representation.
745</t>
746<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="suffix-byte-range-spec"/><iref primary="true" item="Grammar" subitem="suffix-length"/>
747  <x:ref>suffix-byte-range-spec</x:ref> = "-" <x:ref>suffix-length</x:ref>
748  <x:ref>suffix-length</x:ref> = 1*<x:ref>DIGIT</x:ref>
749</artwork></figure>
750<t>
751   A suffix-byte-range-spec is used to specify the suffix of the
752   representation body, of a length given by the suffix-length value. (That is,
753   this form specifies the last N bytes of a representation.) If the
754   representation is shorter than the specified suffix-length, the entire
755   representation is used.
756</t>
757<t>
758   If a syntactically valid byte-range-set includes at least one byte-range-spec
759   whose first-byte-pos is less than the current length of
760   the representation, or at least one suffix-byte-range-spec with a non-zero
761   suffix-length, then the byte-range-set is satisfiable.
762   Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set
763   is unsatisfiable, the server &SHOULD; return a response with a
764   <x:ref>416 (Requested Range Not Satisfiable)</x:ref> status code. Otherwise, the server
765   &SHOULD; return a response with a <x:ref>206 (Partial Content)</x:ref> status code
766   containing the satisfiable ranges of the representation.
767</t>
768<t>
769   Examples of byte-ranges-specifier values (assuming a representation of
770   length 10000):
771  <list style="symbols">
772     <t>The first 500 bytes (byte offsets 0-499, inclusive):
773<figure><artwork type="example" x:indent-with="   ">
774  bytes=0-499
775</artwork></figure>
776    </t>
777     <t>The second 500 bytes (byte offsets 500-999, inclusive):
778<figure><artwork type="example" x:indent-with="   ">
779  bytes=500-999
780</artwork></figure>
781    </t>
782     <t>The final 500 bytes (byte offsets 9500-9999, inclusive):
783<figure><artwork type="example" x:indent-with="   ">
784  bytes=-500
785</artwork></figure>
786    Or:
787<figure><artwork type="example" x:indent-with="   ">
788  bytes=9500-
789</artwork></figure>
790    </t>
791     <t>The first and last bytes only (bytes 0 and 9999):
792<figure><artwork type="example" x:indent-with="   ">
793  bytes=0-0,-1
794</artwork></figure>
795     </t>
796     <t>Several legal but not canonical specifications of the second 500
797        bytes (byte offsets 500-999, inclusive):
798<figure><artwork type="example" x:indent-with="   ">
799  bytes=500-600,601-999
800  bytes=500-700,601-999
801</artwork></figure>
802     </t>
803  </list>
804</t>
805</section>
806
807<section title="Range Retrieval Requests" anchor="range.retrieval.requests">
808  <x:anchor-alias value="Range"/>
809  <x:anchor-alias value="other-ranges-specifier"/>
810  <x:anchor-alias value="other-range-set"/>
811<t>
812   The "Range" header field defines the GET method (conditional or
813   not) to request one or more sub-ranges of the response representation body, instead
814   of the entire representation body.
815</t>
816<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Range"/>
817  <x:ref>Range</x:ref> = <x:ref>byte-ranges-specifier</x:ref> / <x:ref>other-ranges-specifier</x:ref>
818  <x:ref>other-ranges-specifier</x:ref> = <x:ref>other-range-unit</x:ref> "=" <x:ref>other-range-set</x:ref>
819  <x:ref>other-range-set</x:ref> = 1*<x:ref>CHAR</x:ref>
820</artwork></figure>
821<t>
822   A server &MAY; ignore the Range header field. However, origin
823   servers and intermediate caches ought to support byte ranges when
824   possible, since Range supports efficient recovery from partially
825   failed transfers, and supports efficient partial retrieval of large
826   representations.
827</t>
828<t>
829   If the server supports the Range header field and the specified range or
830   ranges are appropriate for the representation:
831  <list style="symbols">
832     <t>The presence of a Range header field in an unconditional GET modifies
833        what is returned if the GET is otherwise successful. In other
834        words, the response carries a status code of <x:ref>206 (Partial Content)</x:ref>
835        instead of 200 (OK).</t>
836
837     <t>The presence of a Range header field in a conditional GET (a request
838        using one or both of If-Modified-Since and If-None-Match, or
839        one or both of If-Unmodified-Since and If-Match) modifies what
840        is returned if the GET is otherwise successful and the
841        condition is true. It does not affect the 304 (Not Modified)
842        response returned if the conditional is false.</t>
843  </list>
844</t>
845<t>
846   In some cases, it might be more appropriate to use the If-Range
847   header field (see <xref target="header.if-range"/>) in addition to the Range
848   header field.
849</t>
850<t>
851   If a proxy that supports ranges receives a Range request, forwards
852   the request to an inbound server, and receives an entire representation in
853   reply, it &MAY; only return the requested range to its client.
854</t>
855</section>
856</section>
857</section>
858
859<section title="IANA Considerations" anchor="IANA.considerations">
860
861<section title="Status Code Registration" anchor="status.code.registration">
862<t>
863   The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
864   shall be updated with the registrations below:
865</t>
866<?BEGININC p5-range.iana-status-codes ?>
867<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
868<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
869   <ttcol>Value</ttcol>
870   <ttcol>Description</ttcol>
871   <ttcol>Reference</ttcol>
872   <c>206</c>
873   <c>Partial Content</c>
874   <c>
875      <xref target="status.206"/>
876   </c>
877   <c>416</c>
878   <c>Requested Range Not Satisfiable</c>
879   <c>
880      <xref target="status.416"/>
881   </c>
882</texttable>
883<!--(END)-->
884<?ENDINC p5-range.iana-status-codes ?>
885</section>
886
887<section title="Header Field Registration" anchor="header.field.registration">
888<t>
889   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
890   with the permanent registrations below (see <xref target="RFC3864"/>):
891</t>
892<?BEGININC p5-range.iana-headers ?>
893<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
894<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
895   <ttcol>Header Field Name</ttcol>
896   <ttcol>Protocol</ttcol>
897   <ttcol>Status</ttcol>
898   <ttcol>Reference</ttcol>
899
900   <c>Accept-Ranges</c>
901   <c>http</c>
902   <c>standard</c>
903   <c>
904      <xref target="header.accept-ranges"/>
905   </c>
906   <c>Content-Range</c>
907   <c>http</c>
908   <c>standard</c>
909   <c>
910      <xref target="header.content-range"/>
911   </c>
912   <c>If-Range</c>
913   <c>http</c>
914   <c>standard</c>
915   <c>
916      <xref target="header.if-range"/>
917   </c>
918   <c>Range</c>
919   <c>http</c>
920   <c>standard</c>
921   <c>
922      <xref target="header.range"/>
923   </c>
924</texttable>
925<!--(END)-->
926<?ENDINC p5-range.iana-headers ?>
927<t>
928   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
929</t>
930</section>
931
932<section title="Range Specifier Registration" anchor="range.specifier.registration">
933<t>
934  The registration procedure for HTTP Range Specifiers is defined by
935  <xref target="range.specifier.registry"/> of this document.
936</t>
937<t>
938   The HTTP Range Specifier Registry shall be created at <eref target="http://www.iana.org/assignments/http-range-specifiers"/>
939   and be populated with the registrations below:
940</t>
941<texttable align="left" suppress-title="true" anchor="iana.range.specifiers.table">
942   <ttcol>Range Specifier Name</ttcol>
943   <ttcol>Description</ttcol>
944   <ttcol>Reference</ttcol>
945
946   <c>bytes</c>
947   <c>a range of octets</c>
948   <c>(this specification)</c>
949</texttable>
950<t>
951   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
952</t>
953</section>
954</section>
955
956<section title="Security Considerations" anchor="security.considerations">
957<t>
958   This section is meant to inform application developers, information
959   providers, and users of the security limitations in HTTP/1.1 as
960   described by this document. The discussion does not include
961   definitive solutions to the problems revealed, though it does make
962   some suggestions for reducing security risks.
963</t>
964<section title="Overlapping Ranges" anchor="overlapping.ranges">
965<t>
966   Range requests containing overlapping ranges can lead to the situation
967   where a server is sending far more data than the size of the complete
968   resource representation.
969</t>
970</section>
971</section>
972
973<section title="Acknowledgments" anchor="acks">
974<t>
975  See &acks;.
976</t>
977</section>
978</middle>
979<back>
980
981<references title="Normative References">
982
983<reference anchor="Part1">
984  <front>
985    <title abbrev="HTTP/1.1">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
986    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
987      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
988      <address><email>fielding@gbiv.com</email></address>
989    </author>
990    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
991      <organization abbrev="W3C">World Wide Web Consortium</organization>
992      <address><email>ylafon@w3.org</email></address>
993    </author>
994    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
995      <organization abbrev="greenbytes">greenbytes GmbH</organization>
996      <address><email>julian.reschke@greenbytes.de</email></address>
997    </author>
998    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
999  </front>
1000  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1001  <x:source href="p1-messaging.xml" basename="p1-messaging"/>
1002</reference>
1003
1004<reference anchor="Part2">
1005  <front>
1006    <title abbrev="HTTP/1.1">HTTP/1.1, part 2: Message Semantics</title>
1007    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1008      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1009      <address><email>fielding@gbiv.com</email></address>
1010    </author>
1011    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1012      <organization abbrev="W3C">World Wide Web Consortium</organization>
1013      <address><email>ylafon@w3.org</email></address>
1014    </author>
1015    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1016      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1017      <address><email>julian.reschke@greenbytes.de</email></address>
1018    </author>
1019    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1020  </front>
1021  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;"/>
1022  <x:source href="p2-semantics.xml" basename="p2-semantics"/>
1023</reference>
1024
1025<reference anchor="Part4">
1026  <front>
1027    <title abbrev="HTTP/1.1">HTTP/1.1, part 4: Conditional Requests</title>
1028    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1029      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1030      <address><email>fielding@gbiv.com</email></address>
1031    </author>
1032    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1033      <organization abbrev="W3C">World Wide Web Consortium</organization>
1034      <address><email>ylafon@w3.org</email></address>
1035    </author>
1036    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1037      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1038      <address><email>julian.reschke@greenbytes.de</email></address>
1039    </author>
1040    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1041  </front>
1042  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1043  <x:source href="p4-conditional.xml" basename="p4-conditional"/>
1044</reference>
1045
1046<reference anchor="Part6">
1047  <front>
1048    <title abbrev="HTTP/1.1">HTTP/1.1, part 6: Caching</title>
1049    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1050      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1051      <address><email>fielding@gbiv.com</email></address>
1052    </author>
1053    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1054      <organization abbrev="W3C">World Wide Web Consortium</organization>
1055      <address><email>ylafon@w3.org</email></address>
1056    </author>
1057    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
1058      <organization>Rackspace</organization>
1059      <address><email>mnot@mnot.net</email></address>
1060    </author>
1061    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1062      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1063      <address><email>julian.reschke@greenbytes.de</email></address>
1064    </author>
1065    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1066  </front>
1067  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
1068  <x:source href="p6-cache.xml" basename="p6-cache"/>
1069</reference>
1070
1071<reference anchor="RFC2046">
1072  <front>
1073    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1074    <author initials="N." surname="Freed" fullname="Ned Freed">
1075      <organization>Innosoft International, Inc.</organization>
1076      <address><email>ned@innosoft.com</email></address>
1077    </author>
1078    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1079      <organization>First Virtual Holdings</organization>
1080      <address><email>nsb@nsb.fv.com</email></address>
1081    </author>
1082    <date month="November" year="1996"/>
1083  </front>
1084  <seriesInfo name="RFC" value="2046"/>
1085</reference>
1086
1087<reference anchor="RFC2119">
1088  <front>
1089    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1090    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1091      <organization>Harvard University</organization>
1092      <address><email>sob@harvard.edu</email></address>
1093    </author>
1094    <date month="March" year="1997"/>
1095  </front>
1096  <seriesInfo name="BCP" value="14"/>
1097  <seriesInfo name="RFC" value="2119"/>
1098</reference>
1099
1100<reference anchor="RFC5234">
1101  <front>
1102    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
1103    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
1104      <organization>Brandenburg InternetWorking</organization>
1105      <address>
1106        <email>dcrocker@bbiw.net</email>
1107      </address> 
1108    </author>
1109    <author initials="P." surname="Overell" fullname="Paul Overell">
1110      <organization>THUS plc.</organization>
1111      <address>
1112        <email>paul.overell@thus.net</email>
1113      </address>
1114    </author>
1115    <date month="January" year="2008"/>
1116  </front>
1117  <seriesInfo name="STD" value="68"/>
1118  <seriesInfo name="RFC" value="5234"/>
1119</reference>
1120
1121</references>
1122
1123<references title="Informative References">
1124
1125<reference anchor="RFC2616">
1126  <front>
1127    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
1128    <author initials="R." surname="Fielding" fullname="R. Fielding">
1129      <organization>University of California, Irvine</organization>
1130      <address><email>fielding@ics.uci.edu</email></address>
1131    </author>
1132    <author initials="J." surname="Gettys" fullname="J. Gettys">
1133      <organization>W3C</organization>
1134      <address><email>jg@w3.org</email></address>
1135    </author>
1136    <author initials="J." surname="Mogul" fullname="J. Mogul">
1137      <organization>Compaq Computer Corporation</organization>
1138      <address><email>mogul@wrl.dec.com</email></address>
1139    </author>
1140    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
1141      <organization>MIT Laboratory for Computer Science</organization>
1142      <address><email>frystyk@w3.org</email></address>
1143    </author>
1144    <author initials="L." surname="Masinter" fullname="L. Masinter">
1145      <organization>Xerox Corporation</organization>
1146      <address><email>masinter@parc.xerox.com</email></address>
1147    </author>
1148    <author initials="P." surname="Leach" fullname="P. Leach">
1149      <organization>Microsoft Corporation</organization>
1150      <address><email>paulle@microsoft.com</email></address>
1151    </author>
1152    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
1153      <organization>W3C</organization>
1154      <address><email>timbl@w3.org</email></address>
1155    </author>
1156    <date month="June" year="1999"/>
1157  </front>
1158  <seriesInfo name="RFC" value="2616"/>
1159</reference>
1160
1161<reference anchor='RFC3864'>
1162  <front>
1163    <title>Registration Procedures for Message Header Fields</title>
1164    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
1165      <organization>Nine by Nine</organization>
1166      <address><email>GK-IETF@ninebynine.org</email></address>
1167    </author>
1168    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
1169      <organization>BEA Systems</organization>
1170      <address><email>mnot@pobox.com</email></address>
1171    </author>
1172    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
1173      <organization>HP Labs</organization>
1174      <address><email>JeffMogul@acm.org</email></address>
1175    </author>
1176    <date year='2004' month='September' />
1177  </front>
1178  <seriesInfo name='BCP' value='90' />
1179  <seriesInfo name='RFC' value='3864' />
1180</reference>
1181
1182<reference anchor="RFC4288">
1183  <front>
1184    <title>Media Type Specifications and Registration Procedures</title>
1185    <author initials="N." surname="Freed" fullname="N. Freed">
1186      <organization>Sun Microsystems</organization>
1187      <address>
1188        <email>ned.freed@mrochek.com</email>
1189      </address>
1190    </author>
1191    <author initials="J." surname="Klensin" fullname="J. Klensin">
1192      <address>
1193        <email>klensin+ietf@jck.com</email>
1194      </address>
1195    </author>
1196    <date year="2005" month="December"/>
1197  </front>
1198  <seriesInfo name="BCP" value="13"/>
1199  <seriesInfo name="RFC" value="4288"/>
1200</reference>
1201
1202<reference anchor='RFC5226'>
1203  <front>
1204    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
1205    <author initials='T.' surname='Narten' fullname='T. Narten'>
1206      <organization>IBM</organization>
1207      <address><email>narten@us.ibm.com</email></address>
1208    </author>
1209    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
1210      <organization>Google</organization>
1211      <address><email>Harald@Alvestrand.no</email></address>
1212    </author>
1213    <date year='2008' month='May' />
1214  </front>
1215  <seriesInfo name='BCP' value='26' />
1216  <seriesInfo name='RFC' value='5226' />
1217</reference>
1218
1219</references>
1220
1221<section title="Internet Media Type multipart/byteranges" anchor="internet.media.type.multipart.byteranges">
1222<iref item="Media Type" subitem="multipart/byteranges" primary="true"/>
1223<iref item="multipart/byteranges Media Type" primary="true"/>
1224<t>
1225   When an HTTP <x:ref>206 (Partial Content)</x:ref> response message includes the
1226   content of multiple ranges (a response to a request for multiple
1227   non-overlapping ranges), these are transmitted as a multipart
1228   message body (<xref target="RFC2046" x:fmt="," x:sec="5.1"/>). The media type for this purpose is called
1229   "multipart/byteranges".  The following is to be registered with IANA <xref target="RFC4288"/>.
1230</t>
1231<x:note>
1232  <t>
1233    &Note; Despite the name "multipart/byteranges" is not limited to the byte ranges only.
1234  </t>
1235</x:note>
1236<t>
1237   The multipart/byteranges media type includes one or more parts, each
1238   with its own Content-Type and Content-Range fields. The required
1239   boundary parameter specifies the boundary string used to separate
1240   each body-part.
1241</t>
1242<t>
1243  <list style="hanging" x:indent="12em">
1244    <t hangText="Type name:">
1245      multipart
1246    </t>
1247    <t hangText="Subtype name:">
1248      byteranges
1249    </t>
1250    <t hangText="Required parameters:">
1251      boundary
1252    </t>
1253    <t hangText="Optional parameters:">
1254      none
1255    </t>
1256    <t hangText="Encoding considerations:">
1257      only "7bit", "8bit", or "binary" are permitted
1258    </t>
1259    <t hangText="Security considerations:">
1260      none
1261    </t>
1262    <t hangText="Interoperability considerations:">
1263      none
1264    </t>
1265    <t hangText="Published specification:">
1266      This specification (see <xref target="internet.media.type.multipart.byteranges"/>).
1267    </t>
1268    <t hangText="Applications that use this media type:">
1269    </t>
1270    <t hangText="Additional information:">
1271      <list style="hanging">
1272        <t hangText="Magic number(s):">none</t>
1273        <t hangText="File extension(s):">none</t>
1274        <t hangText="Macintosh file type code(s):">none</t>
1275      </list>
1276    </t>
1277    <t hangText="Person and email address to contact for further information:">
1278      See Authors Section.
1279    </t>
1280    <t hangText="Intended usage:">
1281      COMMON
1282    </t>
1283    <t hangText="Restrictions on usage:">
1284      none
1285    </t>
1286    <t hangText="Author/Change controller:">
1287      IESG
1288    </t>
1289  </list>
1290</t>
1291<figure><preamble>
1292   For example:
1293</preamble><artwork type="example">
1294  HTTP/1.1 206 Partial Content
1295  Date: Wed, 15 Nov 1995 06:25:24 GMT
1296  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1297  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1298 
1299  --THIS_STRING_SEPARATES
1300  Content-type: application/pdf
1301  Content-range: bytes 500-999/8000
1302 
1303  ...the first range...
1304  --THIS_STRING_SEPARATES
1305  Content-type: application/pdf
1306  Content-range: bytes 7000-7999/8000
1307 
1308  ...the second range
1309  --THIS_STRING_SEPARATES--
1310</artwork></figure>
1311<figure><preamble>
1312   Other example:
1313</preamble>
1314<artwork type="example">
1315  HTTP/1.1 206 Partial Content
1316  Date: Tue, 14 Nov 1995 06:25:24 GMT
1317  Last-Modified: Tue, 14 July 04:58:08 GMT
1318  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1319 
1320  --THIS_STRING_SEPARATES
1321  Content-type: video/example
1322  Content-range: exampleunit 1.2-4.3/25
1323 
1324  ...the first range...
1325  --THIS_STRING_SEPARATES
1326  Content-type: video/example
1327  Content-range: exampleunit 11.2-14.3/25
1328 
1329  ...the second range
1330  --THIS_STRING_SEPARATES--
1331</artwork>
1332</figure>
1333<t>
1334      Notes:
1335  <list style="numbers">
1336      <t>Additional CRLFs &MAY; precede the first boundary string in the body.</t>
1337
1338      <t>Although <xref target="RFC2046"/> permits the boundary string to be
1339         quoted, some existing implementations handle a quoted boundary
1340         string incorrectly.</t>
1341
1342      <t>A number of clients and servers were coded to an early draft
1343         of the byteranges specification to use a media type of
1344         multipart/x-byteranges<iref item="multipart/x-byteranges Media Type"/><iref item="Media Type" subitem="multipart/x-byteranges"/>, which is almost, but not quite
1345         compatible with the version documented in HTTP/1.1.</t>
1346  </list>
1347</t>
1348</section>
1349
1350<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
1351<t>
1352  Clarify that it is not ok to use a weak validator in a 206 response.
1353  (<xref target="status.206"/>)
1354</t>
1355<t>
1356  Change ABNF productions for header fields to only define the field value.
1357  (<xref target="header.field.definitions"/>)
1358</t>
1359<t>
1360  Clarify that multipart/byteranges can consist of a single part.
1361  (<xref target="internet.media.type.multipart.byteranges"/>)
1362</t>
1363</section>
1364
1365<?BEGININC p5-range.abnf-appendix ?>
1366<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
1367<figure>
1368<artwork type="abnf" name="p5-range.parsed-abnf">
1369<x:ref>Accept-Ranges</x:ref> = acceptable-ranges
1370
1371<x:ref>Content-Range</x:ref> = byte-content-range-spec / other-content-range-spec
1372
1373<x:ref>HTTP-date</x:ref> = &lt;HTTP-date, defined in [Part2], Section 5.1&gt;
1374
1375<x:ref>If-Range</x:ref> = entity-tag / HTTP-date
1376
1377<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 3.2.1&gt;
1378
1379<x:ref>Range</x:ref> = byte-ranges-specifier / other-ranges-specifier
1380
1381<x:ref>acceptable-ranges</x:ref> = ( *( "," OWS ) range-unit *( OWS "," [ OWS
1382 range-unit ] ) ) / "none"
1383
1384<x:ref>byte-content-range-spec</x:ref> = bytes-unit SP byte-range-resp-spec "/" (
1385 instance-length / "*" )
1386<x:ref>byte-range-resp-spec</x:ref> = ( first-byte-pos "-" last-byte-pos ) / "*"
1387<x:ref>byte-range-set</x:ref> = *( "," OWS ) ( byte-range-spec /
1388 suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec /
1389 suffix-byte-range-spec ) ] )
1390<x:ref>byte-range-spec</x:ref> = first-byte-pos "-" [ last-byte-pos ]
1391<x:ref>byte-ranges-specifier</x:ref> = bytes-unit "=" byte-range-set
1392<x:ref>bytes-unit</x:ref> = "bytes"
1393
1394<x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in [Part4], Section 2.3&gt;
1395
1396<x:ref>first-byte-pos</x:ref> = 1*DIGIT
1397
1398<x:ref>instance-length</x:ref> = 1*DIGIT
1399
1400<x:ref>last-byte-pos</x:ref> = 1*DIGIT
1401
1402<x:ref>other-content-range-spec</x:ref> = other-range-unit SP other-range-resp-spec
1403<x:ref>other-range-resp-spec</x:ref> = *CHAR
1404<x:ref>other-range-set</x:ref> = 1*CHAR
1405<x:ref>other-range-unit</x:ref> = token
1406<x:ref>other-ranges-specifier</x:ref> = other-range-unit "=" other-range-set
1407
1408<x:ref>range-unit</x:ref> = bytes-unit / other-range-unit
1409
1410<x:ref>suffix-byte-range-spec</x:ref> = "-" suffix-length
1411<x:ref>suffix-length</x:ref> = 1*DIGIT
1412
1413<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.4&gt;
1414</artwork>
1415</figure>
1416<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
1417; Accept-Ranges defined but not used
1418; Content-Range defined but not used
1419; If-Range defined but not used
1420; Range defined but not used
1421</artwork></figure></section>
1422<?ENDINC p5-range.abnf-appendix ?>
1423
1424
1425<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
1426
1427<section title="Since RFC 2616">
1428<t>
1429  Extracted relevant partitions from <xref target="RFC2616"/>.
1430</t>
1431</section>
1432
1433<section title="Since draft-ietf-httpbis-p5-range-00">
1434<t>
1435  Closed issues:
1436  <list style="symbols"> 
1437    <t>
1438      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/18"/>:
1439      "Cache validators in 206 responses"
1440      (<eref target="http://purl.org/NET/http-errata#ifrange206"/>)
1441    </t>
1442    <t>
1443      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
1444      "Normative and Informative references"
1445    </t>
1446    <t>
1447      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
1448      "Normative up-to-date references"
1449    </t>
1450  </list>
1451</t>
1452</section>
1453
1454<section title="Since draft-ietf-httpbis-p5-range-01">
1455<t>
1456  Closed issues:
1457  <list style="symbols"> 
1458    <t>
1459      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
1460      "Updating to RFC4288"
1461    </t>
1462  </list>
1463</t>
1464<t>
1465  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1466  <list style="symbols"> 
1467    <t>
1468      Add explicit references to BNF syntax and rules imported from other parts of the specification.
1469    </t>
1470  </list>
1471</t>
1472</section>
1473
1474<section title="Since draft-ietf-httpbis-p5-range-02" anchor="changes.since.02">
1475<t>
1476  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
1477  <list style="symbols"> 
1478    <t>
1479      Reference RFC 3984, and update header field registrations for headers defined
1480      in this document.
1481    </t>
1482  </list>
1483</t>
1484</section>
1485
1486<section title="Since draft-ietf-httpbis-p5-range-03" anchor="changes.since.03">
1487<t>
1488  None.
1489</t>
1490</section>
1491
1492<section title="Since draft-ietf-httpbis-p5-range-04" anchor="changes.since.04">
1493<t>
1494  Closed issues:
1495  <list style="symbols"> 
1496    <t>
1497      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/133"/>:
1498      "multipart/byteranges minimum number of parts"
1499    </t>
1500  </list>
1501</t>
1502<t>
1503  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1504  <list style="symbols"> 
1505    <t>
1506      Use "/" instead of "|" for alternatives.
1507    </t>
1508    <t>
1509      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
1510      whitespace ("OWS") and required whitespace ("RWS").
1511    </t>
1512    <t>
1513      Rewrite ABNFs to spell out whitespace rules, factor out
1514      header field value format definitions.
1515    </t>
1516  </list>
1517</t>
1518</section>
1519
1520<section title="Since draft-ietf-httpbis-p5-range-05" anchor="changes.since.05">
1521<t>
1522  Closed issues:
1523  <list style="symbols"> 
1524    <t>
1525      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/142"/>:
1526      "State base for *-byte-pos and suffix-length"
1527    </t>
1528  </list>
1529</t>
1530<t>
1531  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1532  <list style="symbols"> 
1533    <t>
1534      Remove bias in favor of byte ranges; allow custom ranges in ABNF.
1535    </t>
1536  </list>
1537</t>
1538<t>
1539  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1540  <list style="symbols"> 
1541    <t>
1542      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
1543    </t>
1544  </list>
1545</t>
1546</section>
1547
1548<section title="Since draft-ietf-httpbis-p5-range-06" anchor="changes.since.06">
1549<t>
1550  Closed issues:
1551  <list style="symbols"> 
1552    <t>
1553      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/161"/>:
1554      "base for numeric protocol elements"
1555    </t>
1556  </list>
1557</t>
1558</section>
1559
1560<section title="Since draft-ietf-httpbis-p5-range-07" anchor="changes.since.07">
1561<t>
1562  Closed issues:
1563  <list style="symbols">
1564    <t>
1565      Fixed discrepancy in the If-Range definition about allowed validators.
1566    </t>
1567    <t>
1568      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/150" />: "multipart/byteranges for custom range units"
1569    </t>
1570    <t>
1571      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/151" />: "range unit missing from other-ranges-specifier in Range header"
1572    </t>
1573    <t>
1574      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/198"/>:
1575      "move IANA registrations for optional status codes"
1576    </t>
1577  </list>
1578</t>
1579</section>
1580
1581<section title="Since draft-ietf-httpbis-p5-range-08" anchor="changes.since.08">
1582<t>
1583  No significant changes.
1584</t>
1585</section>
1586
1587<section title="Since draft-ietf-httpbis-p5-range-09" anchor="changes.since.09">
1588<t>
1589 No significant changes.
1590</t>
1591</section>
1592
1593<section title="Since draft-ietf-httpbis-p5-range-10" anchor="changes.since.10">
1594<t>
1595  Closed issues:
1596  <list style="symbols"> 
1597    <t>
1598      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
1599      "Clarify 'Requested Variant'"
1600    </t>
1601    <t>
1602      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
1603      "Clarify entity / representation / variant terminology"
1604    </t>
1605    <t>
1606      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
1607      "consider removing the 'changes from 2068' sections"
1608    </t>
1609  </list>
1610</t>
1611<t>
1612  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1613  <list style="symbols"> 
1614    <t>
1615      Add IANA registry.
1616    </t>
1617  </list>
1618</t>
1619</section>
1620
1621<section title="Since draft-ietf-httpbis-p5-range-11" anchor="changes.since.11">
1622<t>
1623  Closed issues:
1624  <list style="symbols"> 
1625    <t>
1626      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/217"/>:
1627      "Caches can't be required to serve ranges"
1628    </t>
1629  </list>
1630</t>
1631</section>
1632
1633<section title="Since draft-ietf-httpbis-p5-range-12" anchor="changes.since.12">
1634<t>
1635  Closed issues:
1636  <list style="symbols"> 
1637    <t>
1638      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
1639      "Header Classification"
1640    </t>
1641  </list>
1642</t>
1643</section>
1644
1645<section title="Since draft-ietf-httpbis-p5-range-13" anchor="changes.since.13">
1646<t>
1647  Closed issues:
1648  <list style="symbols">
1649    <t>
1650      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
1651      "untangle ABNFs for header fields"
1652    </t>
1653  </list>
1654</t>
1655</section>
1656
1657<section title="Since draft-ietf-httpbis-p5-range-14" anchor="changes.since.14">
1658<t>
1659  None.
1660</t>
1661</section>
1662
1663<section title="Since draft-ietf-httpbis-p5-range-15" anchor="changes.since.15">
1664<t>
1665  Closed issues:
1666  <list style="symbols">
1667    <t>
1668      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/175"/>:
1669      "Security consideration: range flooding"
1670    </t>
1671  </list>
1672</t>
1673</section>
1674
1675<section title="Since draft-ietf-httpbis-p5-range-16" anchor="changes.since.16">
1676<t>
1677  Closed issues:
1678  <list style="symbols"> 
1679    <t>
1680      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/186"/>:
1681      "Document HTTP's error-handling philosophy"
1682    </t>
1683    <t>
1684      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/301"/>:
1685      "Content-Range on responses other than 206"
1686    </t>
1687    <t>
1688      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/319"/>:
1689      "case sensitivity of ranges in p5"
1690    </t>
1691  </list>
1692</t>
1693</section>
1694
1695<section title="Since draft-ietf-httpbis-p5-range-17" anchor="changes.since.17">
1696<t>
1697  None.
1698</t>
1699</section>
1700
1701<section title="Since draft-ietf-httpbis-p5-range-18" anchor="changes.since.18">
1702<t>
1703  Closed issues:
1704  <list style="symbols"> 
1705    <t>
1706      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/311"/>:
1707      "Add limitations to Range to reduce its use as a denial-of-service tool"
1708    </t>
1709  </list>
1710</t>
1711</section>
1712
1713<section title="Since draft-ietf-httpbis-p5-range-19" anchor="changes.since.19">
1714<t>
1715  Closed issues:
1716  <list style="symbols"> 
1717    <t>
1718      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/358"/>:
1719      "ABNF list expansion code problem"
1720    </t>
1721    <t>
1722      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/361"/>:
1723      "ABNF requirements for recipients"
1724    </t>
1725  </list>
1726</t>
1727</section>
1728
1729</section>
1730
1731</back>
1732</rfc>
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