source: draft-ietf-httpbis/diffs/draft-ietf-httpbis-p4-conditional-22-from-21.diff.html @ 2323

Last change on this file since 2323 was 2190, checked in by julian.reschke@…, 7 years ago

prepare -22 for release

  • Property svn:eol-style set to native
  • Property svn:mime-type set to text/html; charset=iso-8859-1
File size: 254.7 KB
Line 
1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
2<!-- Generated by rfcdiff 1.38: rfcdiff  -->
3<!-- <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional" > -->
4<html> 
5<head> 
6  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
7  <meta http-equiv="Content-Style-Type" content="text/css" />
8  <title>Diff: draft-ietf-httpbis-p4-conditional-21.txt - draft-ietf-httpbis-p4-conditional-22.txt</title>
9  <style type="text/css">
10    body    { margin: 0.4ex; margin-right: auto; }
11    tr      { }
12    td      { white-space: pre; font-family: monospace; vertical-align: top; font-size: 0.86em;}
13    th      { font-size: 0.86em; }
14    .small  { font-size: 0.6em; font-style: italic; font-family: Verdana, Helvetica, sans-serif; }
15    .left   { background-color: #EEE; }
16    .right  { background-color: #FFF; }
17    .diff   { background-color: #CCF; }
18    .lblock { background-color: #BFB; }
19    .rblock { background-color: #FF8; }
20    .insert { background-color: #8FF; }
21    .delete { background-color: #ACF; }
22    .void   { background-color: #FFB; }
23    .cont   { background-color: #EEE; }
24    .linebr { background-color: #AAA; }
25    .lineno { color: red; background-color: #FFF; font-size: 0.7em; text-align: right; padding: 0 2px; }
26    .elipsis{ background-color: #AAA; }
27    .left .cont { background-color: #DDD; }
28    .right .cont { background-color: #EEE; }
29    .lblock .cont { background-color: #9D9; }
30    .rblock .cont { background-color: #DD6; }
31    .insert .cont { background-color: #0DD; }
32    .delete .cont { background-color: #8AD; }
33    .stats, .stats td, .stats th { background-color: #EEE; padding: 2px 0; }
34  </style>
35</head>
36<body > 
37  <table border="0" cellpadding="0" cellspacing="0">
38  <tr bgcolor="orange"><th></th><th>&nbsp;draft-ietf-httpbis-p4-conditional-21.txt&nbsp;</th><th> </th><th>&nbsp;draft-ietf-httpbis-p4-conditional-22.txt&nbsp;</th><th></th></tr>
39      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
40      <tr><td class="lineno" valign="top"></td><td class="left">HTTPbis Working Group                                   R. Fielding, Ed.</td><td> </td><td class="right">HTTPbis Working Group                                   R. Fielding, Ed.</td><td class="lineno" valign="top"></td></tr>
41      <tr><td class="lineno" valign="top"></td><td class="left">Internet-Draft                                                     Adobe</td><td> </td><td class="right">Internet-Draft                                                     Adobe</td><td class="lineno" valign="top"></td></tr>
42      <tr><td class="lineno" valign="top"></td><td class="left">Obsoletes: 2616 (if approved)                            J. Reschke, Ed.</td><td> </td><td class="right">Obsoletes: 2616 (if approved)                            J. Reschke, Ed.</td><td class="lineno" valign="top"></td></tr>
43      <tr><td class="lineno" valign="top"></td><td class="left">Intended status: Standards Track                              greenbytes</td><td> </td><td class="right">Intended status: Standards Track                              greenbytes</td><td class="lineno" valign="top"></td></tr>
44      <tr><td><a name="diff0001" /></td></tr>
45      <tr><td class="lineno" valign="top"></td><td class="lblock">Expires: A<span class="delete">pril 7, 2013                                   October 4, 2012</span></td><td> </td><td class="rblock">Expires: A<span class="insert">ugust 27, 2013                               February 23, 2013</span></td><td class="lineno" valign="top"></td></tr>
46      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
47      <tr><td class="lineno" valign="top"></td><td class="left">      Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests</td><td> </td><td class="right">      Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests</td><td class="lineno" valign="top"></td></tr>
48      <tr><td><a name="diff0002" /></td></tr>
49      <tr><td class="lineno" valign="top"></td><td class="lblock">                  draft-ietf-httpbis-p4-conditional-2<span class="delete">1</span></td><td> </td><td class="rblock">                  draft-ietf-httpbis-p4-conditional-2<span class="insert">2</span></td><td class="lineno" valign="top"></td></tr>
50      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
51      <tr><td class="lineno" valign="top"></td><td class="left">Abstract</td><td> </td><td class="right">Abstract</td><td class="lineno" valign="top"></td></tr>
52      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
53      <tr><td class="lineno" valign="top"></td><td class="left">   The Hypertext Transfer Protocol (HTTP) is an application-level</td><td> </td><td class="right">   The Hypertext Transfer Protocol (HTTP) is an application-level</td><td class="lineno" valign="top"></td></tr>
54      <tr><td class="lineno" valign="top"></td><td class="left">   protocol for distributed, collaborative, hypertext information</td><td> </td><td class="right">   protocol for distributed, collaborative, hypertext information</td><td class="lineno" valign="top"></td></tr>
55      <tr><td class="lineno" valign="top"></td><td class="left">   systems.  This document defines HTTP/1.1 conditional requests,</td><td> </td><td class="right">   systems.  This document defines HTTP/1.1 conditional requests,</td><td class="lineno" valign="top"></td></tr>
56      <tr><td class="lineno" valign="top"></td><td class="left">   including metadata header fields for indicating state changes,</td><td> </td><td class="right">   including metadata header fields for indicating state changes,</td><td class="lineno" valign="top"></td></tr>
57      <tr><td class="lineno" valign="top"></td><td class="left">   request header fields for making preconditions on such state, and</td><td> </td><td class="right">   request header fields for making preconditions on such state, and</td><td class="lineno" valign="top"></td></tr>
58      <tr><td class="lineno" valign="top"></td><td class="left">   rules for constructing the responses to a conditional request when</td><td> </td><td class="right">   rules for constructing the responses to a conditional request when</td><td class="lineno" valign="top"></td></tr>
59      <tr><td class="lineno" valign="top"></td><td class="left">   one or more preconditions evaluate to false.</td><td> </td><td class="right">   one or more preconditions evaluate to false.</td><td class="lineno" valign="top"></td></tr>
60      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
61      <tr bgcolor="gray" ><td></td><th><a name="part-l2" /><small>skipping to change at</small><em> page 1, line 33</em></th><th> </th><th><a name="part-r2" /><small>skipping to change at</small><em> page 1, line 33</em></th><td></td></tr>
62      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
63      <tr><td class="lineno" valign="top"></td><td class="left">   Discussion of this draft takes place on the HTTPBIS working group</td><td> </td><td class="right">   Discussion of this draft takes place on the HTTPBIS working group</td><td class="lineno" valign="top"></td></tr>
64      <tr><td class="lineno" valign="top"></td><td class="left">   mailing list (ietf-http-wg@w3.org), which is archived at</td><td> </td><td class="right">   mailing list (ietf-http-wg@w3.org), which is archived at</td><td class="lineno" valign="top"></td></tr>
65      <tr><td class="lineno" valign="top"></td><td class="left">   &lt;http://lists.w3.org/Archives/Public/ietf-http-wg/&gt;.</td><td> </td><td class="right">   &lt;http://lists.w3.org/Archives/Public/ietf-http-wg/&gt;.</td><td class="lineno" valign="top"></td></tr>
66      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
67      <tr><td class="lineno" valign="top"></td><td class="left">   The current issues list is at</td><td> </td><td class="right">   The current issues list is at</td><td class="lineno" valign="top"></td></tr>
68      <tr><td class="lineno" valign="top"></td><td class="left">   &lt;http://tools.ietf.org/wg/httpbis/trac/report/3&gt; and related</td><td> </td><td class="right">   &lt;http://tools.ietf.org/wg/httpbis/trac/report/3&gt; and related</td><td class="lineno" valign="top"></td></tr>
69      <tr><td class="lineno" valign="top"></td><td class="left">   documents (including fancy diffs) can be found at</td><td> </td><td class="right">   documents (including fancy diffs) can be found at</td><td class="lineno" valign="top"></td></tr>
70      <tr><td class="lineno" valign="top"></td><td class="left">   &lt;http://tools.ietf.org/wg/httpbis/&gt;.</td><td> </td><td class="right">   &lt;http://tools.ietf.org/wg/httpbis/&gt;.</td><td class="lineno" valign="top"></td></tr>
71      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
72      <tr><td><a name="diff0003" /></td></tr>
73      <tr><td class="lineno" valign="top"></td><td class="lblock">   The changes in this draft are summarized in Appendix D.<span class="delete">2</span>.</td><td> </td><td class="rblock">   The changes in this draft are summarized in Appendix D.<span class="insert">3</span>.</td><td class="lineno" valign="top"></td></tr>
74      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
75      <tr><td class="lineno" valign="top"></td><td class="left">Status of This Memo</td><td> </td><td class="right">Status of This Memo</td><td class="lineno" valign="top"></td></tr>
76      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
77      <tr><td class="lineno" valign="top"></td><td class="left">   This Internet-Draft is submitted in full conformance with the</td><td> </td><td class="right">   This Internet-Draft is submitted in full conformance with the</td><td class="lineno" valign="top"></td></tr>
78      <tr><td class="lineno" valign="top"></td><td class="left">   provisions of BCP 78 and BCP 79.</td><td> </td><td class="right">   provisions of BCP 78 and BCP 79.</td><td class="lineno" valign="top"></td></tr>
79      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
80      <tr><td class="lineno" valign="top"></td><td class="left">   Internet-Drafts are working documents of the Internet Engineering</td><td> </td><td class="right">   Internet-Drafts are working documents of the Internet Engineering</td><td class="lineno" valign="top"></td></tr>
81      <tr><td class="lineno" valign="top"></td><td class="left">   Task Force (IETF).  Note that other groups may also distribute</td><td> </td><td class="right">   Task Force (IETF).  Note that other groups may also distribute</td><td class="lineno" valign="top"></td></tr>
82      <tr><td class="lineno" valign="top"></td><td class="left">   working documents as Internet-Drafts.  The list of current Internet-</td><td> </td><td class="right">   working documents as Internet-Drafts.  The list of current Internet-</td><td class="lineno" valign="top"></td></tr>
83      <tr><td class="lineno" valign="top"></td><td class="left">   Drafts is at http://datatracker.ietf.org/drafts/current/.</td><td> </td><td class="right">   Drafts is at http://datatracker.ietf.org/drafts/current/.</td><td class="lineno" valign="top"></td></tr>
84      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
85      <tr><td class="lineno" valign="top"></td><td class="left">   Internet-Drafts are draft documents valid for a maximum of six months</td><td> </td><td class="right">   Internet-Drafts are draft documents valid for a maximum of six months</td><td class="lineno" valign="top"></td></tr>
86      <tr><td class="lineno" valign="top"></td><td class="left">   and may be updated, replaced, or obsoleted by other documents at any</td><td> </td><td class="right">   and may be updated, replaced, or obsoleted by other documents at any</td><td class="lineno" valign="top"></td></tr>
87      <tr><td class="lineno" valign="top"></td><td class="left">   time.  It is inappropriate to use Internet-Drafts as reference</td><td> </td><td class="right">   time.  It is inappropriate to use Internet-Drafts as reference</td><td class="lineno" valign="top"></td></tr>
88      <tr><td class="lineno" valign="top"></td><td class="left">   material or to cite them other than as "work in progress."</td><td> </td><td class="right">   material or to cite them other than as "work in progress."</td><td class="lineno" valign="top"></td></tr>
89      <tr><td><a name="diff0004" /></td></tr>
90      <tr><td class="lineno" valign="top"></td><td class="lblock">   This Internet-Draft will expire on A<span class="delete">pril </span>7, 2013.</td><td> </td><td class="rblock">   This Internet-Draft will expire on A<span class="insert">ugust 2</span>7, 2013.</td><td class="lineno" valign="top"></td></tr>
91      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
92      <tr><td class="lineno" valign="top"></td><td class="left">Copyright Notice</td><td> </td><td class="right">Copyright Notice</td><td class="lineno" valign="top"></td></tr>
93      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
94      <tr><td><a name="diff0005" /></td></tr>
95      <tr><td class="lineno" valign="top"></td><td class="lblock">   Copyright (c) 201<span class="delete">2</span> IETF Trust and the persons identified as the</td><td> </td><td class="rblock">   Copyright (c) 201<span class="insert">3</span> IETF Trust and the persons identified as the</td><td class="lineno" valign="top"></td></tr>
96      <tr><td class="lineno" valign="top"></td><td class="left">   document authors.  All rights reserved.</td><td> </td><td class="right">   document authors.  All rights reserved.</td><td class="lineno" valign="top"></td></tr>
97      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
98      <tr><td class="lineno" valign="top"></td><td class="left">   This document is subject to BCP 78 and the IETF Trust's Legal</td><td> </td><td class="right">   This document is subject to BCP 78 and the IETF Trust's Legal</td><td class="lineno" valign="top"></td></tr>
99      <tr><td class="lineno" valign="top"></td><td class="left">   Provisions Relating to IETF Documents</td><td> </td><td class="right">   Provisions Relating to IETF Documents</td><td class="lineno" valign="top"></td></tr>
100      <tr><td class="lineno" valign="top"></td><td class="left">   (http://trustee.ietf.org/license-info) in effect on the date of</td><td> </td><td class="right">   (http://trustee.ietf.org/license-info) in effect on the date of</td><td class="lineno" valign="top"></td></tr>
101      <tr><td class="lineno" valign="top"></td><td class="left">   publication of this document.  Please review these documents</td><td> </td><td class="right">   publication of this document.  Please review these documents</td><td class="lineno" valign="top"></td></tr>
102      <tr><td class="lineno" valign="top"></td><td class="left">   carefully, as they describe your rights and restrictions with respect</td><td> </td><td class="right">   carefully, as they describe your rights and restrictions with respect</td><td class="lineno" valign="top"></td></tr>
103      <tr><td class="lineno" valign="top"></td><td class="left">   to this document.  Code Components extracted from this document must</td><td> </td><td class="right">   to this document.  Code Components extracted from this document must</td><td class="lineno" valign="top"></td></tr>
104      <tr><td class="lineno" valign="top"></td><td class="left">   include Simplified BSD License text as described in Section 4.e of</td><td> </td><td class="right">   include Simplified BSD License text as described in Section 4.e of</td><td class="lineno" valign="top"></td></tr>
105      <tr><td class="lineno" valign="top"></td><td class="left">   the Trust Legal Provisions and are provided without warranty as</td><td> </td><td class="right">   the Trust Legal Provisions and are provided without warranty as</td><td class="lineno" valign="top"></td></tr>
106      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
107      <tr bgcolor="gray" ><td></td><th><a name="part-l3" /><small>skipping to change at</small><em> page 3, line 9</em></th><th> </th><th><a name="part-r3" /><small>skipping to change at</small><em> page 3, line 9</em></th><td></td></tr>
108      <tr><td class="lineno" valign="top"></td><td class="left">   the copyright in such materials, this document may not be modified</td><td> </td><td class="right">   the copyright in such materials, this document may not be modified</td><td class="lineno" valign="top"></td></tr>
109      <tr><td class="lineno" valign="top"></td><td class="left">   outside the IETF Standards Process, and derivative works of it may</td><td> </td><td class="right">   outside the IETF Standards Process, and derivative works of it may</td><td class="lineno" valign="top"></td></tr>
110      <tr><td class="lineno" valign="top"></td><td class="left">   not be created outside the IETF Standards Process, except to format</td><td> </td><td class="right">   not be created outside the IETF Standards Process, except to format</td><td class="lineno" valign="top"></td></tr>
111      <tr><td class="lineno" valign="top"></td><td class="left">   it for publication as an RFC or to translate it into languages other</td><td> </td><td class="right">   it for publication as an RFC or to translate it into languages other</td><td class="lineno" valign="top"></td></tr>
112      <tr><td class="lineno" valign="top"></td><td class="left">   than English.</td><td> </td><td class="right">   than English.</td><td class="lineno" valign="top"></td></tr>
113      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
114      <tr><td class="lineno" valign="top"></td><td class="left">Table of Contents</td><td> </td><td class="right">Table of Contents</td><td class="lineno" valign="top"></td></tr>
115      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
116      <tr><td class="lineno" valign="top"></td><td class="left">   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4</td><td> </td><td class="right">   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4</td><td class="lineno" valign="top"></td></tr>
117      <tr><td class="lineno" valign="top"></td><td class="left">     1.1.  Conformance and Error Handling . . . . . . . . . . . . . .  4</td><td> </td><td class="right">     1.1.  Conformance and Error Handling . . . . . . . . . . . . . .  4</td><td class="lineno" valign="top"></td></tr>
118      <tr><td><a name="diff0006" /></td></tr>
119      <tr><td class="lineno" valign="top"></td><td class="lblock">     1.2.  Syntax Notation  . . . . . . . . . . . . . . . . . . . . .  <span class="delete">5</span></td><td> </td><td class="rblock">     1.2.  Syntax Notation  . . . . . . . . . . . . . . . . . . . . .  <span class="insert">4</span></td><td class="lineno" valign="top"></td></tr>
120      <tr><td class="lineno" valign="top"></td><td class="left">   2.  Validators . . . . . . . . . . . . . . . . . . . . . . . . . .  5</td><td> </td><td class="right">   2.  Validators . . . . . . . . . . . . . . . . . . . . . . . . . .  5</td><td class="lineno" valign="top"></td></tr>
121      <tr><td class="lineno" valign="top"></td><td class="left">     2.1.  Weak versus Strong . . . . . . . . . . . . . . . . . . . .  5</td><td> </td><td class="right">     2.1.  Weak versus Strong . . . . . . . . . . . . . . . . . . . .  5</td><td class="lineno" valign="top"></td></tr>
122      <tr><td class="lineno" valign="top"></td><td class="left">     2.2.  Last-Modified  . . . . . . . . . . . . . . . . . . . . . .  7</td><td> </td><td class="right">     2.2.  Last-Modified  . . . . . . . . . . . . . . . . . . . . . .  7</td><td class="lineno" valign="top"></td></tr>
123      <tr><td class="lineno" valign="top"></td><td class="left">       2.2.1.  Generation . . . . . . . . . . . . . . . . . . . . . .  7</td><td> </td><td class="right">       2.2.1.  Generation . . . . . . . . . . . . . . . . . . . . . .  7</td><td class="lineno" valign="top"></td></tr>
124      <tr><td class="lineno" valign="top"></td><td class="left">       2.2.2.  Comparison . . . . . . . . . . . . . . . . . . . . . .  8</td><td> </td><td class="right">       2.2.2.  Comparison . . . . . . . . . . . . . . . . . . . . . .  8</td><td class="lineno" valign="top"></td></tr>
125      <tr><td class="lineno" valign="top"></td><td class="left">     2.3.  ETag . . . . . . . . . . . . . . . . . . . . . . . . . . .  9</td><td> </td><td class="right">     2.3.  ETag . . . . . . . . . . . . . . . . . . . . . . . . . . .  9</td><td class="lineno" valign="top"></td></tr>
126      <tr><td class="lineno" valign="top"></td><td class="left">       2.3.1.  Generation . . . . . . . . . . . . . . . . . . . . . . 10</td><td> </td><td class="right">       2.3.1.  Generation . . . . . . . . . . . . . . . . . . . . . . 10</td><td class="lineno" valign="top"></td></tr>
127      <tr><td class="lineno" valign="top"></td><td class="left">       2.3.2.  Comparison . . . . . . . . . . . . . . . . . . . . . . 10</td><td> </td><td class="right">       2.3.2.  Comparison . . . . . . . . . . . . . . . . . . . . . . 10</td><td class="lineno" valign="top"></td></tr>
128      <tr><td><a name="diff0007" /></td></tr>
129      <tr><td class="lineno" valign="top"></td><td class="lblock">       2.3.3.  Example: Entity-tags <span class="delete">v</span>arying on Content-Negotiated</td><td> </td><td class="rblock">       2.3.3.  Example: Entity-tags <span class="insert">V</span>arying on Content-Negotiated</td><td class="lineno" valign="top"></td></tr>
130      <tr><td class="lineno" valign="top"></td><td class="left">               Resources  . . . . . . . . . . . . . . . . . . . . . . 11</td><td> </td><td class="right">               Resources  . . . . . . . . . . . . . . . . . . . . . . 11</td><td class="lineno" valign="top"></td></tr>
131      <tr><td><a name="diff0008" /></td></tr>
132      <tr><td class="lineno" valign="top"></td><td class="lblock">     2.4.  <span class="delete">Rules for</span> When to Use Entity-tags and Last-Modified</td><td> </td><td class="rblock">     2.4.  When to Use Entity-tags and Last-Modified Dates  . . . . . 12</td><td class="lineno" valign="top"></td></tr>
133      <tr><td class="lineno" valign="top"></td><td class="lblock">           Dates  <span class="delete">. . . . . . . . . . . . . . . . . . . . .</span> . . . . . 12</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
134      <tr><td class="lineno" valign="top"></td><td class="left">   3.  Precondition Header Fields . . . . . . . . . . . . . . . . . . 13</td><td> </td><td class="right">   3.  Precondition Header Fields . . . . . . . . . . . . . . . . . . 13</td><td class="lineno" valign="top"></td></tr>
135      <tr><td class="lineno" valign="top"></td><td class="left">     3.1.  If-Match . . . . . . . . . . . . . . . . . . . . . . . . . 13</td><td> </td><td class="right">     3.1.  If-Match . . . . . . . . . . . . . . . . . . . . . . . . . 13</td><td class="lineno" valign="top"></td></tr>
136      <tr><td class="lineno" valign="top"></td><td class="left">     3.2.  If-None-Match  . . . . . . . . . . . . . . . . . . . . . . 14</td><td> </td><td class="right">     3.2.  If-None-Match  . . . . . . . . . . . . . . . . . . . . . . 14</td><td class="lineno" valign="top"></td></tr>
137      <tr><td><a name="diff0009" /></td></tr>
138      <tr><td class="lineno" valign="top"></td><td class="lblock">     3.3.  If-Modified-Since  . . . . . . . . . . . . . . . . . . . . <span class="delete">16</span></td><td> </td><td class="rblock">     3.3.  If-Modified-Since  . . . . . . . . . . . . . . . . . . . . <span class="insert">15</span></td><td class="lineno" valign="top"></td></tr>
139      <tr><td class="lineno" valign="top"></td><td class="lblock">     3.4.  If-Unmodified-Since  . . . . . . . . . . . . . . . . . . . <span class="delete">17</span></td><td> </td><td class="rblock">     3.4.  If-Unmodified-Since  . . . . . . . . . . . . . . . . . . . <span class="insert">16</span></td><td class="lineno" valign="top"></td></tr>
140      <tr><td class="lineno" valign="top"></td><td class="lblock">     3.5.  If-Range . . . . . . . . . . . . . . . . . . . . . . . . . <span class="delete">17</span></td><td> </td><td class="rblock">     3.5.  If-Range . . . . . . . . . . . . . . . . . . . . . . . . . <span class="insert">16</span></td><td class="lineno" valign="top"></td></tr>
141      <tr><td class="lineno" valign="top"></td><td class="lblock">   4.  Status Code Definitions  . . . . . . . . . . . . . . . . . . . <span class="delete">18</span></td><td> </td><td class="rblock">   4.  Status Code Definitions  . . . . . . . . . . . . . . . . . . . <span class="insert">17</span></td><td class="lineno" valign="top"></td></tr>
142      <tr><td class="lineno" valign="top"></td><td class="lblock">     4.1.  304 Not Modified . . . . . . . . . . . . . . . . . . . . . <span class="delete">18</span></td><td> </td><td class="rblock">     4.1.  304 Not Modified . . . . . . . . . . . . . . . . . . . . . <span class="insert">17</span></td><td class="lineno" valign="top"></td></tr>
143      <tr><td class="lineno" valign="top"></td><td class="lblock">     4.2.  412 Precondition Failed  . . . . . . . . . . . . . . . . . <span class="delete">18</span></td><td> </td><td class="rblock">     4.2.  412 Precondition Failed  . . . . . . . . . . . . . . . . . <span class="insert">17</span></td><td class="lineno" valign="top"></td></tr>
144      <tr><td class="lineno" valign="top"></td><td class="lblock">   5.  Precedence . . . . . . . . . . . . . . . . . . <span class="delete">. . . . . . . . 19</span></td><td> </td><td class="rblock">   5.  <span class="insert">Evaluation and</span> Precedence  . . . . . . . . . . . . . . . . . . <span class="insert">17</span></td><td class="lineno" valign="top"></td></tr>
145      <tr><td class="lineno" valign="top"></td><td class="left">   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 20</td><td> </td><td class="right">   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 20</td><td class="lineno" valign="top"></td></tr>
146      <tr><td class="lineno" valign="top"></td><td class="left">     6.1.  Status Code Registration . . . . . . . . . . . . . . . . . 20</td><td> </td><td class="right">     6.1.  Status Code Registration . . . . . . . . . . . . . . . . . 20</td><td class="lineno" valign="top"></td></tr>
147      <tr><td class="lineno" valign="top"></td><td class="left">     6.2.  Header Field Registration  . . . . . . . . . . . . . . . . 20</td><td> </td><td class="right">     6.2.  Header Field Registration  . . . . . . . . . . . . . . . . 20</td><td class="lineno" valign="top"></td></tr>
148      <tr><td><a name="diff0010" /></td></tr>
149      <tr><td class="lineno" valign="top"></td><td class="lblock">   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 2<span class="delete">1</span></td><td> </td><td class="rblock">   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 2<span class="insert">0</span></td><td class="lineno" valign="top"></td></tr>
150      <tr><td class="lineno" valign="top"></td><td class="left">   8.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 21</td><td> </td><td class="right">   8.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 21</td><td class="lineno" valign="top"></td></tr>
151      <tr><td class="lineno" valign="top"></td><td class="left">   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 21</td><td> </td><td class="right">   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 21</td><td class="lineno" valign="top"></td></tr>
152      <tr><td class="lineno" valign="top"></td><td class="left">     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 21</td><td> </td><td class="right">     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 21</td><td class="lineno" valign="top"></td></tr>
153      <tr><td class="lineno" valign="top"></td><td class="left">     9.2.  Informative References . . . . . . . . . . . . . . . . . . 22</td><td> </td><td class="right">     9.2.  Informative References . . . . . . . . . . . . . . . . . . 22</td><td class="lineno" valign="top"></td></tr>
154      <tr><td class="lineno" valign="top"></td><td class="left">   Appendix A.  Changes from RFC 2616 . . . . . . . . . . . . . . . . 22</td><td> </td><td class="right">   Appendix A.  Changes from RFC 2616 . . . . . . . . . . . . . . . . 22</td><td class="lineno" valign="top"></td></tr>
155      <tr><td class="lineno" valign="top"></td><td class="left">   Appendix B.  Imported ABNF . . . . . . . . . . . . . . . . . . . . 22</td><td> </td><td class="right">   Appendix B.  Imported ABNF . . . . . . . . . . . . . . . . . . . . 22</td><td class="lineno" valign="top"></td></tr>
156      <tr><td class="lineno" valign="top"></td><td class="left">   Appendix C.  Collected ABNF  . . . . . . . . . . . . . . . . . . . 23</td><td> </td><td class="right">   Appendix C.  Collected ABNF  . . . . . . . . . . . . . . . . . . . 23</td><td class="lineno" valign="top"></td></tr>
157      <tr><td class="lineno" valign="top"></td><td class="left">   Appendix D.  Change Log (to be removed by RFC Editor before</td><td> </td><td class="right">   Appendix D.  Change Log (to be removed by RFC Editor before</td><td class="lineno" valign="top"></td></tr>
158      <tr><td class="lineno" valign="top"></td><td class="left">                publication)  . . . . . . . . . . . . . . . . . . . . 23</td><td> </td><td class="right">                publication)  . . . . . . . . . . . . . . . . . . . . 23</td><td class="lineno" valign="top"></td></tr>
159      <tr><td class="lineno" valign="top"></td><td class="left">     D.1.  Since draft-ietf-httpbis-p4-conditional-19 . . . . . . . . 23</td><td> </td><td class="right">     D.1.  Since draft-ietf-httpbis-p4-conditional-19 . . . . . . . . 23</td><td class="lineno" valign="top"></td></tr>
160      <tr><td class="lineno" valign="top"></td><td class="left">     D.2.  Since draft-ietf-httpbis-p4-conditional-20 . . . . . . . . 24</td><td> </td><td class="right">     D.2.  Since draft-ietf-httpbis-p4-conditional-20 . . . . . . . . 24</td><td class="lineno" valign="top"></td></tr>
161      <tr><td><a name="diff0011" /></td></tr>
162      <tr><td class="lineno" valign="top"></td><td class="lblock">   Index  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <span class="delete">24</span></td><td> </td><td class="rblock">     <span class="insert">D.3.  Since draft-ietf-httpbis-p4-conditional-21 . . . . . . . . 24</span></td><td class="lineno" valign="top"></td></tr>
163      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   Index  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <span class="insert">25</span></td><td class="lineno" valign="top"></td></tr>
164      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
165      <tr><td class="lineno" valign="top"></td><td class="left">1.  Introduction</td><td> </td><td class="right">1.  Introduction</td><td class="lineno" valign="top"></td></tr>
166      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
167      <tr><td class="lineno" valign="top"></td><td class="left">   Conditional requests are HTTP requests [Part2] that include one or</td><td> </td><td class="right">   Conditional requests are HTTP requests [Part2] that include one or</td><td class="lineno" valign="top"></td></tr>
168      <tr><td class="lineno" valign="top"></td><td class="left">   more header fields indicating a precondition to be tested before</td><td> </td><td class="right">   more header fields indicating a precondition to be tested before</td><td class="lineno" valign="top"></td></tr>
169      <tr><td><a name="diff0012" /></td></tr>
170      <tr><td class="lineno" valign="top"></td><td class="lblock">   applying the method semantics to the target resource.  <span class="delete">Each</span></td><td> </td><td class="rblock">   applying the method semantics to the target resource.  This document</td><td class="lineno" valign="top"></td></tr>
171      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   precondition is based on metadata that is expected to change if the</span></td><td> </td><td class="rblock">   defines the HTTP/1.1 conditional request mechanisms in terms of the</td><td class="lineno" valign="top"></td></tr>
172      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   selected representation of the target resource is changed.</span>  This</td><td> </td><td class="rblock">   architecture, syntax notation, and conformance criteria defined in</td><td class="lineno" valign="top"></td></tr>
173      <tr><td class="lineno" valign="top"></td><td class="lblock">   document defines the HTTP/1.1 conditional request mechanisms in terms</td><td> </td><td class="rblock">   [Part1].</td><td class="lineno" valign="top"></td></tr>
174      <tr><td class="lineno" valign="top"></td><td class="lblock">   of the architecture, syntax notation, and conformance criteria</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
175      <tr><td class="lineno" valign="top"></td><td class="lblock">   defined in [Part1].</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
176      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
177      <tr><td class="lineno" valign="top"></td><td class="left">   Conditional GET requests are the most efficient mechanism for HTTP</td><td> </td><td class="right">   Conditional GET requests are the most efficient mechanism for HTTP</td><td class="lineno" valign="top"></td></tr>
178      <tr><td class="lineno" valign="top"></td><td class="left">   cache updates [Part6].  Conditionals can also be applied to state-</td><td> </td><td class="right">   cache updates [Part6].  Conditionals can also be applied to state-</td><td class="lineno" valign="top"></td></tr>
179      <tr><td class="lineno" valign="top"></td><td class="left">   changing methods, such as PUT and DELETE, to prevent the "lost</td><td> </td><td class="right">   changing methods, such as PUT and DELETE, to prevent the "lost</td><td class="lineno" valign="top"></td></tr>
180      <tr><td class="lineno" valign="top"></td><td class="left">   update" problem: one client accidentally overwriting the work of</td><td> </td><td class="right">   update" problem: one client accidentally overwriting the work of</td><td class="lineno" valign="top"></td></tr>
181      <tr><td class="lineno" valign="top"></td><td class="left">   another client that has been acting in parallel.</td><td> </td><td class="right">   another client that has been acting in parallel.</td><td class="lineno" valign="top"></td></tr>
182      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
183      <tr><td class="lineno" valign="top"></td><td class="left">   Conditional request preconditions are based on the state of the</td><td> </td><td class="right">   Conditional request preconditions are based on the state of the</td><td class="lineno" valign="top"></td></tr>
184      <tr><td class="lineno" valign="top"></td><td class="left">   target resource as a whole (its current value set) or the state as</td><td> </td><td class="right">   target resource as a whole (its current value set) or the state as</td><td class="lineno" valign="top"></td></tr>
185      <tr><td class="lineno" valign="top"></td><td class="left">   observed in a previously obtained representation (one value in that</td><td> </td><td class="right">   observed in a previously obtained representation (one value in that</td><td class="lineno" valign="top"></td></tr>
186      <tr><td class="lineno" valign="top"></td><td class="left">   set).  A resource might have multiple current representations, each</td><td> </td><td class="right">   set).  A resource might have multiple current representations, each</td><td class="lineno" valign="top"></td></tr>
187      <tr><td class="lineno" valign="top"></td><td class="left">   with its own observable state.  The conditional request mechanisms</td><td> </td><td class="right">   with its own observable state.  The conditional request mechanisms</td><td class="lineno" valign="top"></td></tr>
188      <tr><td><a name="diff0013" /></td></tr>
189      <tr><td class="lineno" valign="top"></td><td class="lblock">   assume that the mapping of requests to <span class="delete">corresponding representations</span></td><td> </td><td class="rblock">   assume that the mapping of requests to <span class="insert">a "selected representation"</span></td><td class="lineno" valign="top"></td></tr>
190      <tr><td class="lineno" valign="top"></td><td class="lblock">   will be consistent over time if the server intends to take advantage</td><td> </td><td class="rblock"><span class="insert">   (Section 3 of [Part2])</span> will be consistent over time if the server</td><td class="lineno" valign="top"></td></tr>
191      <tr><td class="lineno" valign="top"></td><td class="lblock">   of conditionals.  Regardless, if the mapping is inconsistent and the</td><td> </td><td class="rblock">   intends to take advantage of conditionals.  Regardless, if the</td><td class="lineno" valign="top"></td></tr>
192      <tr><td class="lineno" valign="top"></td><td class="lblock">   server is unable to select the appropriate representation, then no</td><td> </td><td class="rblock">   mapping is inconsistent and the server is unable to select the</td><td class="lineno" valign="top"></td></tr>
193      <tr><td class="lineno" valign="top"></td><td class="lblock">   harm will result when the precondition evaluates to false.</td><td> </td><td class="rblock">   appropriate representation, then no harm will result when the</td><td class="lineno" valign="top"></td></tr>
194      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   precondition evaluates to false.</td><td class="lineno" valign="top"></td></tr>
195      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
196      <tr><td><a name="diff0014" /></td></tr>
197      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">We use the term "selected representation" to refer to the current</span></td><td> </td><td class="rblock">   The conditional request preconditions <span class="insert">defined by this specification</span></td><td class="lineno" valign="top"></td></tr>
198      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   representation of the target resource that would have been selected</span></td><td> </td><td class="rblock">   are evaluated by comparing the <span class="insert">validators</span> provided in the <span class="insert">conditional</span></td><td class="lineno" valign="top"></td></tr>
199      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   in a successful response if the same request had used the method GET</span></td><td> </td><td class="rblock">   request header fields to the current <span class="insert">validators</span> for the selected</td><td class="lineno" valign="top"></td></tr>
200      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   and had excluded all of the conditional request header fields.</span>  The</td><td> </td><td class="rblock">   <span class="insert">representation in the order defined by Section 5.</span></td><td class="lineno" valign="top"></td></tr>
201      <tr><td class="lineno" valign="top"></td><td class="lblock">   conditional request preconditions are evaluated by comparing the</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
202      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">values</span> provided in the request header fields to the current <span class="delete">metadata</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
203      <tr><td class="lineno" valign="top"></td><td class="lblock">   for the selected <span class="delete">representation.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
204      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
205      <tr><td class="lineno" valign="top"></td><td class="left">1.1.  Conformance and Error Handling</td><td> </td><td class="right">1.1.  Conformance and Error Handling</td><td class="lineno" valign="top"></td></tr>
206      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
207      <tr><td class="lineno" valign="top"></td><td class="left">   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",</td><td> </td><td class="right">   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",</td><td class="lineno" valign="top"></td></tr>
208      <tr><td class="lineno" valign="top"></td><td class="left">   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this</td><td> </td><td class="right">   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this</td><td class="lineno" valign="top"></td></tr>
209      <tr><td class="lineno" valign="top"></td><td class="left">   document are to be interpreted as described in [RFC2119].</td><td> </td><td class="right">   document are to be interpreted as described in [RFC2119].</td><td class="lineno" valign="top"></td></tr>
210      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
211      <tr><td class="lineno" valign="top"></td><td class="left">   Conformance criteria and considerations regarding error handling are</td><td> </td><td class="right">   Conformance criteria and considerations regarding error handling are</td><td class="lineno" valign="top"></td></tr>
212      <tr><td class="lineno" valign="top"></td><td class="left">   defined in Section 2.5 of [Part1].</td><td> </td><td class="right">   defined in Section 2.5 of [Part1].</td><td class="lineno" valign="top"></td></tr>
213      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
214      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
215      <tr bgcolor="gray" ><td></td><th><a name="part-l4" /><small>skipping to change at</small><em> page 5, line 34</em></th><th> </th><th><a name="part-r4" /><small>skipping to change at</small><em> page 5, line 26</em></th><td></td></tr>
216      <tr><td class="lineno" valign="top"></td><td class="left">2.1.  Weak versus Strong</td><td> </td><td class="right">2.1.  Weak versus Strong</td><td class="lineno" valign="top"></td></tr>
217      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
218      <tr><td class="lineno" valign="top"></td><td class="left">   Validators come in two flavors: strong or weak.  Weak validators are</td><td> </td><td class="right">   Validators come in two flavors: strong or weak.  Weak validators are</td><td class="lineno" valign="top"></td></tr>
219      <tr><td class="lineno" valign="top"></td><td class="left">   easy to generate but are far less useful for comparisons.  Strong</td><td> </td><td class="right">   easy to generate but are far less useful for comparisons.  Strong</td><td class="lineno" valign="top"></td></tr>
220      <tr><td class="lineno" valign="top"></td><td class="left">   validators are ideal for comparisons but can be very difficult (and</td><td> </td><td class="right">   validators are ideal for comparisons but can be very difficult (and</td><td class="lineno" valign="top"></td></tr>
221      <tr><td class="lineno" valign="top"></td><td class="left">   occasionally impossible) to generate efficiently.  Rather than impose</td><td> </td><td class="right">   occasionally impossible) to generate efficiently.  Rather than impose</td><td class="lineno" valign="top"></td></tr>
222      <tr><td class="lineno" valign="top"></td><td class="left">   that all forms of resource adhere to the same strength of validator,</td><td> </td><td class="right">   that all forms of resource adhere to the same strength of validator,</td><td class="lineno" valign="top"></td></tr>
223      <tr><td class="lineno" valign="top"></td><td class="left">   HTTP exposes the type of validator in use and imposes restrictions on</td><td> </td><td class="right">   HTTP exposes the type of validator in use and imposes restrictions on</td><td class="lineno" valign="top"></td></tr>
224      <tr><td class="lineno" valign="top"></td><td class="left">   when weak validators can be used as preconditions.</td><td> </td><td class="right">   when weak validators can be used as preconditions.</td><td class="lineno" valign="top"></td></tr>
225      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
226      <tr><td><a name="diff0015" /></td></tr>
227      <tr><td class="lineno" valign="top"></td><td class="lblock">   A "strong validator" is <span class="delete">a</span> representation metadata <span class="delete">value</span> that <span class="delete">MUST be</span></td><td> </td><td class="rblock">   A "strong validator" is representation metadata that <span class="insert">changes</span> value</td><td class="lineno" valign="top"></td></tr>
228      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   changed to a new, previously unused or guaranteed unique,</span> value</td><td> </td><td class="rblock">   whenever a change occurs to the representation data that would be</td><td class="lineno" valign="top"></td></tr>
229      <tr><td class="lineno" valign="top"></td><td class="lblock">   whenever a change occurs to the representation data <span class="delete">such</span> that <span class="delete">a</span></td><td> </td><td class="rblock">   observable in the payload body of a 200 (OK) response to GET.</td><td class="lineno" valign="top"></td></tr>
230      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   change</span> would be observable in the payload body of a 200 (OK) response</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
231      <tr><td class="lineno" valign="top"></td><td class="lblock">   to GET.</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
232      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
233      <tr><td><a name="diff0016" /></td></tr>
234      <tr><td class="lineno" valign="top"></td><td class="lblock">   A strong validator <span class="delete">MAY be changed</span> for other reasons, such as when a</td><td> </td><td class="rblock">   A strong validator <span class="insert">might change</span> for other reasons, such as when a</td><td class="lineno" valign="top"></td></tr>
235      <tr><td class="lineno" valign="top"></td><td class="left">   semantically significant part of the representation metadata is</td><td> </td><td class="right">   semantically significant part of the representation metadata is</td><td class="lineno" valign="top"></td></tr>
236      <tr><td class="lineno" valign="top"></td><td class="left">   changed (e.g., Content-Type), but it is in the best interests of the</td><td> </td><td class="right">   changed (e.g., Content-Type), but it is in the best interests of the</td><td class="lineno" valign="top"></td></tr>
237      <tr><td class="lineno" valign="top"></td><td class="left">   origin server to only change the value when it is necessary to</td><td> </td><td class="right">   origin server to only change the value when it is necessary to</td><td class="lineno" valign="top"></td></tr>
238      <tr><td class="lineno" valign="top"></td><td class="left">   invalidate the stored responses held by remote caches and authoring</td><td> </td><td class="right">   invalidate the stored responses held by remote caches and authoring</td><td class="lineno" valign="top"></td></tr>
239      <tr><td><a name="diff0017" /></td></tr>
240      <tr><td class="lineno" valign="top"></td><td class="lblock">   tools.  A strong validator <span class="delete">MUST be</span> unique across all representations</td><td> </td><td class="rblock">   tools.  A strong validator <span class="insert">is</span> unique across all representations of a</td><td class="lineno" valign="top"></td></tr>
241      <tr><td class="lineno" valign="top"></td><td class="lblock">   of a given resource, such that no two representations of that</td><td> </td><td class="rblock">   given resource, such that no two representations of that resource <span class="insert">can</span></td><td class="lineno" valign="top"></td></tr>
242      <tr><td class="lineno" valign="top"></td><td class="lblock">   resource share the same validator unless their <span class="delete">payload body would be</span></td><td> </td><td class="rblock">   share the same validator unless their <span class="insert">representation data is</span></td><td class="lineno" valign="top"></td></tr>
243      <tr><td class="lineno" valign="top"></td><td class="left">   identical.</td><td> </td><td class="right">   identical.</td><td class="lineno" valign="top"></td></tr>
244      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
245      <tr><td class="lineno" valign="top"></td><td class="left">   Cache entries might persist for arbitrarily long periods, regardless</td><td> </td><td class="right">   Cache entries might persist for arbitrarily long periods, regardless</td><td class="lineno" valign="top"></td></tr>
246      <tr><td class="lineno" valign="top"></td><td class="left">   of expiration times.  Thus, a cache might attempt to validate an</td><td> </td><td class="right">   of expiration times.  Thus, a cache might attempt to validate an</td><td class="lineno" valign="top"></td></tr>
247      <tr><td class="lineno" valign="top"></td><td class="left">   entry using a validator that it obtained in the distant past.  A</td><td> </td><td class="right">   entry using a validator that it obtained in the distant past.  A</td><td class="lineno" valign="top"></td></tr>
248      <tr><td><a name="diff0018" /></td></tr>
249      <tr><td class="lineno" valign="top"></td><td class="lblock">   strong validator <span class="delete">MUST be</span> unique across all versions of all</td><td> </td><td class="rblock">   strong validator <span class="insert">is</span> unique across all versions of all representations</td><td class="lineno" valign="top"></td></tr>
250      <tr><td class="lineno" valign="top"></td><td class="lblock">   representations associated with a particular resource over time.</td><td> </td><td class="rblock">   associated with a particular resource over time.  However, there is</td><td class="lineno" valign="top"></td></tr>
251      <tr><td class="lineno" valign="top"></td><td class="lblock">   However, there is no implication of uniqueness across representations</td><td> </td><td class="rblock">   no implication of uniqueness across representations of different</td><td class="lineno" valign="top"></td></tr>
252      <tr><td class="lineno" valign="top"></td><td class="lblock">   of different resources (i.e., the same strong validator might be in</td><td> </td><td class="rblock">   resources (i.e., the same strong validator might be in use for</td><td class="lineno" valign="top"></td></tr>
253      <tr><td class="lineno" valign="top"></td><td class="lblock">   use for representations of multiple resources at the same time and</td><td> </td><td class="rblock">   representations of multiple resources at the same time and does not</td><td class="lineno" valign="top"></td></tr>
254      <tr><td class="lineno" valign="top"></td><td class="lblock">   does not imply that those representations are equivalent).</td><td> </td><td class="rblock">   imply that those representations are equivalent).</td><td class="lineno" valign="top"></td></tr>
255      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
256      <tr><td class="lineno" valign="top"></td><td class="left">   There are a variety of strong validators used in practice.  The best</td><td> </td><td class="right">   There are a variety of strong validators used in practice.  The best</td><td class="lineno" valign="top"></td></tr>
257      <tr><td class="lineno" valign="top"></td><td class="left">   are based on strict revision control, wherein each change to a</td><td> </td><td class="right">   are based on strict revision control, wherein each change to a</td><td class="lineno" valign="top"></td></tr>
258      <tr><td class="lineno" valign="top"></td><td class="left">   representation always results in a unique node name and revision</td><td> </td><td class="right">   representation always results in a unique node name and revision</td><td class="lineno" valign="top"></td></tr>
259      <tr><td class="lineno" valign="top"></td><td class="left">   identifier being assigned before the representation is made</td><td> </td><td class="right">   identifier being assigned before the representation is made</td><td class="lineno" valign="top"></td></tr>
260      <tr><td class="lineno" valign="top"></td><td class="left">   accessible to GET.  A collision-resistant hash function applied to</td><td> </td><td class="right">   accessible to GET.  A collision-resistant hash function applied to</td><td class="lineno" valign="top"></td></tr>
261      <tr><td class="lineno" valign="top"></td><td class="left">   the representation data is also sufficient if the data is available</td><td> </td><td class="right">   the representation data is also sufficient if the data is available</td><td class="lineno" valign="top"></td></tr>
262      <tr><td class="lineno" valign="top"></td><td class="left">   prior to the response header fields being sent and the digest does</td><td> </td><td class="right">   prior to the response header fields being sent and the digest does</td><td class="lineno" valign="top"></td></tr>
263      <tr><td class="lineno" valign="top"></td><td class="left">   not need to be recalculated every time a validation request is</td><td> </td><td class="right">   not need to be recalculated every time a validation request is</td><td class="lineno" valign="top"></td></tr>
264      <tr><td class="lineno" valign="top"></td><td class="left">   received.  However, if a resource has distinct representations that</td><td> </td><td class="right">   received.  However, if a resource has distinct representations that</td><td class="lineno" valign="top"></td></tr>
265      <tr><td class="lineno" valign="top"></td><td class="left">   differ only in their metadata, such as might occur with content</td><td> </td><td class="right">   differ only in their metadata, such as might occur with content</td><td class="lineno" valign="top"></td></tr>
266      <tr><td class="lineno" valign="top"></td><td class="left">   negotiation over media types that happen to share the same data</td><td> </td><td class="right">   negotiation over media types that happen to share the same data</td><td class="lineno" valign="top"></td></tr>
267      <tr><td class="lineno" valign="top"></td><td class="left">   format, then the origin server SHOULD incorporate additional</td><td> </td><td class="right">   format, then the origin server SHOULD incorporate additional</td><td class="lineno" valign="top"></td></tr>
268      <tr><td class="lineno" valign="top"></td><td class="left">   information in the validator to distinguish those representations and</td><td> </td><td class="right">   information in the validator to distinguish those representations and</td><td class="lineno" valign="top"></td></tr>
269      <tr><td class="lineno" valign="top"></td><td class="left">   avoid confusing cache behavior.</td><td> </td><td class="right">   avoid confusing cache behavior.</td><td class="lineno" valign="top"></td></tr>
270      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
271      <tr><td><a name="diff0019" /></td></tr>
272      <tr><td class="lineno" valign="top"></td><td class="lblock">   In contrast, a "weak validator" is <span class="delete">a</span> representation metadata <span class="delete">value</span></td><td> </td><td class="rblock">   In contrast, a "weak validator" is representation metadata that might</td><td class="lineno" valign="top"></td></tr>
273      <tr><td class="lineno" valign="top"></td><td class="lblock">   that might not <span class="delete">be changed</span> for every change to the representation</td><td> </td><td class="rblock">   not <span class="insert">change</span> for every change to the representation data.  This</td><td class="lineno" valign="top"></td></tr>
274      <tr><td class="lineno" valign="top"></td><td class="lblock">   data.  This weakness might be due to limitations in how the value is</td><td> </td><td class="rblock">   weakness might be due to limitations in how the value is calculated,</td><td class="lineno" valign="top"></td></tr>
275      <tr><td class="lineno" valign="top"></td><td class="lblock">   calculated, such as clock resolution or an inability to ensure</td><td> </td><td class="rblock">   such as clock resolution or an inability to ensure uniqueness for all</td><td class="lineno" valign="top"></td></tr>
276      <tr><td class="lineno" valign="top"></td><td class="lblock">   uniqueness for all possible representations of the resource, or due</td><td> </td><td class="rblock">   possible representations of the resource, or due to a desire by the</td><td class="lineno" valign="top"></td></tr>
277      <tr><td class="lineno" valign="top"></td><td class="lblock">   to a desire by the resource owner to group representations by some</td><td> </td><td class="rblock">   resource owner to group representations by some self-determined set</td><td class="lineno" valign="top"></td></tr>
278      <tr><td class="lineno" valign="top"></td><td class="lblock">   self-determined set of equivalency rather than unique sequences of</td><td> </td><td class="rblock">   of equivalency rather than unique sequences of data.  An origin</td><td class="lineno" valign="top"></td></tr>
279      <tr><td class="lineno" valign="top"></td><td class="lblock">   data.  An origin server SHOULD change a weak entity-tag whenever it</td><td> </td><td class="rblock">   server SHOULD change a weak entity-tag whenever it considers prior</td><td class="lineno" valign="top"></td></tr>
280      <tr><td class="lineno" valign="top"></td><td class="lblock">   considers prior representations to be unacceptable as a substitute</td><td> </td><td class="rblock">   representations to be unacceptable as a substitute for the current</td><td class="lineno" valign="top"></td></tr>
281      <tr><td class="lineno" valign="top"></td><td class="lblock">   for the current representation.  In other words, a weak entity-tag</td><td> </td><td class="rblock">   representation.  In other words, a weak entity-tag ought to change</td><td class="lineno" valign="top"></td></tr>
282      <tr><td class="lineno" valign="top"></td><td class="lblock">   ought to change whenever the origin server wants caches to invalidate</td><td> </td><td class="rblock">   whenever the origin server wants caches to invalidate old responses.</td><td class="lineno" valign="top"></td></tr>
283      <tr><td class="lineno" valign="top"></td><td class="lblock">   old responses.</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
284      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
285      <tr><td class="lineno" valign="top"></td><td class="left">   For example, the representation of a weather report that changes in</td><td> </td><td class="right">   For example, the representation of a weather report that changes in</td><td class="lineno" valign="top"></td></tr>
286      <tr><td class="lineno" valign="top"></td><td class="left">   content every second, based on dynamic measurements, might be grouped</td><td> </td><td class="right">   content every second, based on dynamic measurements, might be grouped</td><td class="lineno" valign="top"></td></tr>
287      <tr><td class="lineno" valign="top"></td><td class="left">   into sets of equivalent representations (from the origin server's</td><td> </td><td class="right">   into sets of equivalent representations (from the origin server's</td><td class="lineno" valign="top"></td></tr>
288      <tr><td class="lineno" valign="top"></td><td class="left">   perspective) with the same weak validator in order to allow cached</td><td> </td><td class="right">   perspective) with the same weak validator in order to allow cached</td><td class="lineno" valign="top"></td></tr>
289      <tr><td class="lineno" valign="top"></td><td class="left">   representations to be valid for a reasonable period of time (perhaps</td><td> </td><td class="right">   representations to be valid for a reasonable period of time (perhaps</td><td class="lineno" valign="top"></td></tr>
290      <tr><td class="lineno" valign="top"></td><td class="left">   adjusted dynamically based on server load or weather quality).</td><td> </td><td class="right">   adjusted dynamically based on server load or weather quality).</td><td class="lineno" valign="top"></td></tr>
291      <tr><td class="lineno" valign="top"></td><td class="left">   Likewise, a representation's modification time, if defined with only</td><td> </td><td class="right">   Likewise, a representation's modification time, if defined with only</td><td class="lineno" valign="top"></td></tr>
292      <tr><td class="lineno" valign="top"></td><td class="left">   one-second resolution, might be a weak validator if it is possible</td><td> </td><td class="right">   one-second resolution, might be a weak validator if it is possible</td><td class="lineno" valign="top"></td></tr>
293      <tr><td class="lineno" valign="top"></td><td class="left">   for the representation to be modified twice during a single second</td><td> </td><td class="right">   for the representation to be modified twice during a single second</td><td class="lineno" valign="top"></td></tr>
294      <tr><td class="lineno" valign="top"></td><td class="left">   and retrieved between those modifications.</td><td> </td><td class="right">   and retrieved between those modifications.</td><td class="lineno" valign="top"></td></tr>
295      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
296      <tr><td><a name="diff0020" /></td></tr>
297      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   <span class="insert">Likewise, a validator is weak if it is shared by two or more</span></td><td class="lineno" valign="top"></td></tr>
298      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   representations of a given resource at the same time, unless those</span></td><td class="lineno" valign="top"></td></tr>
299      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   representations have identical representation data.  For example, if</span></td><td class="lineno" valign="top"></td></tr>
300      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   the origin server sends the same validator for a representation with</span></td><td class="lineno" valign="top"></td></tr>
301      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   a gzip content coding applied as it does for a representation with no</span></td><td class="lineno" valign="top"></td></tr>
302      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   content coding, then that validator is weak.  However, two</span></td><td class="lineno" valign="top"></td></tr>
303      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   simultaneous representations might share the same strong validator if</span></td><td class="lineno" valign="top"></td></tr>
304      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   they differ only in the representation metadata, such as when two</span></td><td class="lineno" valign="top"></td></tr>
305      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   different media types are available for the same representation data.</span></td><td class="lineno" valign="top"></td></tr>
306      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">                                                                         </td><td class="lineno" valign="top"></td></tr>
307      <tr><td class="lineno" valign="top"></td><td class="left">   A "use" of a validator occurs when either a client generates a</td><td> </td><td class="right">   A "use" of a validator occurs when either a client generates a</td><td class="lineno" valign="top"></td></tr>
308      <tr><td class="lineno" valign="top"></td><td class="left">   request and includes the validator in a precondition or when a server</td><td> </td><td class="right">   request and includes the validator in a precondition or when a server</td><td class="lineno" valign="top"></td></tr>
309      <tr><td class="lineno" valign="top"></td><td class="left">   compares two validators.  Weak validators are only usable in contexts</td><td> </td><td class="right">   compares two validators.  Weak validators are only usable in contexts</td><td class="lineno" valign="top"></td></tr>
310      <tr><td><a name="diff0021" /></td></tr>
311      <tr><td class="lineno" valign="top"></td><td class="lblock">   that do not depend on exact equality of <span class="delete">a representation's payload</span></td><td> </td><td class="rblock">   that do not depend on exact equality of <span class="insert">the representation data.</span></td><td class="lineno" valign="top"></td></tr>
312      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   body.</span>  Strong validators are usable and preferred for all conditional</td><td> </td><td class="rblock">   Strong validators are usable and preferred for all conditional</td><td class="lineno" valign="top"></td></tr>
313      <tr><td class="lineno" valign="top"></td><td class="left">   requests, including cache validation, partial content ranges, and</td><td> </td><td class="right">   requests, including cache validation, partial content ranges, and</td><td class="lineno" valign="top"></td></tr>
314      <tr><td class="lineno" valign="top"></td><td class="left">   "lost update" avoidance.</td><td> </td><td class="right">   "lost update" avoidance.</td><td class="lineno" valign="top"></td></tr>
315      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
316      <tr><td class="lineno" valign="top"></td><td class="left">2.2.  Last-Modified</td><td> </td><td class="right">2.2.  Last-Modified</td><td class="lineno" valign="top"></td></tr>
317      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
318      <tr><td><a name="diff0022" /></td></tr>
319      <tr><td class="lineno" valign="top"></td><td class="lblock">   The "Last-Modified" header field <span class="delete">indicates</span> the date and time at which</td><td> </td><td class="rblock">   The "Last-Modified" header field <span class="insert">in a response provides a timestamp</span></td><td class="lineno" valign="top"></td></tr>
320      <tr><td class="lineno" valign="top"></td><td class="lblock">   the origin server believes the selected representation was last</td><td> </td><td class="rblock"><span class="insert">   indicating</span> the date and time at which the origin server believes the</td><td class="lineno" valign="top"></td></tr>
321      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">modified.</span></td><td> </td><td class="rblock">   selected representation was last <span class="insert">modified, as determined at the</span></td><td class="lineno" valign="top"></td></tr>
322      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   conclusion of handling the request.</span></td><td class="lineno" valign="top"></td></tr>
323      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
324      <tr><td class="lineno" valign="top"></td><td class="left">     Last-Modified = HTTP-date</td><td> </td><td class="right">     Last-Modified = HTTP-date</td><td class="lineno" valign="top"></td></tr>
325      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
326      <tr><td class="lineno" valign="top"></td><td class="left">   An example of its use is</td><td> </td><td class="right">   An example of its use is</td><td class="lineno" valign="top"></td></tr>
327      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
328      <tr><td class="lineno" valign="top"></td><td class="left">     Last-Modified: Tue, 15 Nov 1994 12:45:26 GMT</td><td> </td><td class="right">     Last-Modified: Tue, 15 Nov 1994 12:45:26 GMT</td><td class="lineno" valign="top"></td></tr>
329      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
330      <tr><td class="lineno" valign="top"></td><td class="left">2.2.1.  Generation</td><td> </td><td class="right">2.2.1.  Generation</td><td class="lineno" valign="top"></td></tr>
331      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
332      <tr><td class="lineno" valign="top"></td><td class="left">   Origin servers SHOULD send Last-Modified for any selected</td><td> </td><td class="right">   Origin servers SHOULD send Last-Modified for any selected</td><td class="lineno" valign="top"></td></tr>
333      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
334      <tr bgcolor="gray" ><td></td><th><a name="part-l5" /><small>skipping to change at</small><em> page 9, line 11</em></th><th> </th><th><a name="part-r5" /><small>skipping to change at</small><em> page 9, line 11</em></th><td></td></tr>
335      <tr><td class="lineno" valign="top"></td><td class="left">   same Last-Modified time, then at least one of those responses would</td><td> </td><td class="right">   same Last-Modified time, then at least one of those responses would</td><td class="lineno" valign="top"></td></tr>
336      <tr><td class="lineno" valign="top"></td><td class="left">   have a Date value equal to its Last-Modified time.  The arbitrary 60-</td><td> </td><td class="right">   have a Date value equal to its Last-Modified time.  The arbitrary 60-</td><td class="lineno" valign="top"></td></tr>
337      <tr><td class="lineno" valign="top"></td><td class="left">   second limit guards against the possibility that the Date and Last-</td><td> </td><td class="right">   second limit guards against the possibility that the Date and Last-</td><td class="lineno" valign="top"></td></tr>
338      <tr><td class="lineno" valign="top"></td><td class="left">   Modified values are generated from different clocks, or at somewhat</td><td> </td><td class="right">   Modified values are generated from different clocks, or at somewhat</td><td class="lineno" valign="top"></td></tr>
339      <tr><td class="lineno" valign="top"></td><td class="left">   different times during the preparation of the response.  An</td><td> </td><td class="right">   different times during the preparation of the response.  An</td><td class="lineno" valign="top"></td></tr>
340      <tr><td class="lineno" valign="top"></td><td class="left">   implementation MAY use a value larger than 60 seconds, if it is</td><td> </td><td class="right">   implementation MAY use a value larger than 60 seconds, if it is</td><td class="lineno" valign="top"></td></tr>
341      <tr><td class="lineno" valign="top"></td><td class="left">   believed that 60 seconds is too short.</td><td> </td><td class="right">   believed that 60 seconds is too short.</td><td class="lineno" valign="top"></td></tr>
342      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
343      <tr><td class="lineno" valign="top"></td><td class="left">2.3.  ETag</td><td> </td><td class="right">2.3.  ETag</td><td class="lineno" valign="top"></td></tr>
344      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
345      <tr><td><a name="diff0023" /></td></tr>
346      <tr><td class="lineno" valign="top"></td><td class="lblock">   The "ETag" header field provides the current entity-tag for the</td><td> </td><td class="rblock">   The "ETag" header field <span class="insert">in a response</span> provides the current entity-tag</td><td class="lineno" valign="top"></td></tr>
347      <tr><td class="lineno" valign="top"></td><td class="lblock">   selected <span class="delete">representation.</span>  An entity-tag is an opaque validator for</td><td> </td><td class="rblock">   for the selected <span class="insert">representation, as determined at the conclusion of</span></td><td class="lineno" valign="top"></td></tr>
348      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   handling the request.</span>  An entity-tag is an opaque validator for</td><td class="lineno" valign="top"></td></tr>
349      <tr><td class="lineno" valign="top"></td><td class="left">   differentiating between multiple representations of the same</td><td> </td><td class="right">   differentiating between multiple representations of the same</td><td class="lineno" valign="top"></td></tr>
350      <tr><td class="lineno" valign="top"></td><td class="left">   resource, regardless of whether those multiple representations are</td><td> </td><td class="right">   resource, regardless of whether those multiple representations are</td><td class="lineno" valign="top"></td></tr>
351      <tr><td class="lineno" valign="top"></td><td class="left">   due to resource state changes over time, content negotiation</td><td> </td><td class="right">   due to resource state changes over time, content negotiation</td><td class="lineno" valign="top"></td></tr>
352      <tr><td class="lineno" valign="top"></td><td class="left">   resulting in multiple representations being valid at the same time,</td><td> </td><td class="right">   resulting in multiple representations being valid at the same time,</td><td class="lineno" valign="top"></td></tr>
353      <tr><td class="lineno" valign="top"></td><td class="left">   or both.  An entity-tag consists of an opaque quoted string, possibly</td><td> </td><td class="right">   or both.  An entity-tag consists of an opaque quoted string, possibly</td><td class="lineno" valign="top"></td></tr>
354      <tr><td class="lineno" valign="top"></td><td class="left">   prefixed by a weakness indicator.</td><td> </td><td class="right">   prefixed by a weakness indicator.</td><td class="lineno" valign="top"></td></tr>
355      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
356      <tr><td class="lineno" valign="top"></td><td class="left">     ETag       = entity-tag</td><td> </td><td class="right">     ETag       = entity-tag</td><td class="lineno" valign="top"></td></tr>
357      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
358      <tr><td class="lineno" valign="top"></td><td class="left">     entity-tag = [ weak ] opaque-tag</td><td> </td><td class="right">     entity-tag = [ weak ] opaque-tag</td><td class="lineno" valign="top"></td></tr>
359      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
360      <tr bgcolor="gray" ><td></td><th><a name="part-l6" /><small>skipping to change at</small><em> page 9, line 48</em></th><th> </th><th><a name="part-r6" /><small>skipping to change at</small><em> page 9, line 49</em></th><td></td></tr>
361      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
362      <tr><td class="lineno" valign="top"></td><td class="left">   Examples:</td><td> </td><td class="right">   Examples:</td><td class="lineno" valign="top"></td></tr>
363      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
364      <tr><td class="lineno" valign="top"></td><td class="left">     ETag: "xyzzy"</td><td> </td><td class="right">     ETag: "xyzzy"</td><td class="lineno" valign="top"></td></tr>
365      <tr><td class="lineno" valign="top"></td><td class="left">     ETag: W/"xyzzy"</td><td> </td><td class="right">     ETag: W/"xyzzy"</td><td class="lineno" valign="top"></td></tr>
366      <tr><td class="lineno" valign="top"></td><td class="left">     ETag: ""</td><td> </td><td class="right">     ETag: ""</td><td class="lineno" valign="top"></td></tr>
367      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
368      <tr><td class="lineno" valign="top"></td><td class="left">   An entity-tag can be either a weak or strong validator, with strong</td><td> </td><td class="right">   An entity-tag can be either a weak or strong validator, with strong</td><td class="lineno" valign="top"></td></tr>
369      <tr><td class="lineno" valign="top"></td><td class="left">   being the default.  If an origin server provides an entity-tag for a</td><td> </td><td class="right">   being the default.  If an origin server provides an entity-tag for a</td><td class="lineno" valign="top"></td></tr>
370      <tr><td class="lineno" valign="top"></td><td class="left">   representation and the generation of that entity-tag does not satisfy</td><td> </td><td class="right">   representation and the generation of that entity-tag does not satisfy</td><td class="lineno" valign="top"></td></tr>
371      <tr><td><a name="diff0024" /></td></tr>
372      <tr><td class="lineno" valign="top"></td><td class="lblock">   the <span class="delete">requirements for</span> a strong validator (Section 2.1), then <span class="delete">that</span></td><td> </td><td class="rblock">   <span class="insert">all of</span> the <span class="insert">characteristics of</span> a strong validator (Section 2.1), then</td><td class="lineno" valign="top"></td></tr>
373      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   entity-tag</span> MUST <span class="delete">be marked</span> as weak by prefixing its opaque value with</td><td> </td><td class="rblock">   <span class="insert">the origin server</span> MUST <span class="insert">mark the entity-tag</span> as weak by prefixing its</td><td class="lineno" valign="top"></td></tr>
374      <tr><td class="lineno" valign="top"></td><td class="lblock">   "W/" (case-sensitive).</td><td> </td><td class="rblock">   opaque value with "W/" (case-sensitive).</td><td class="lineno" valign="top"></td></tr>
375      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
376      <tr><td class="lineno" valign="top"></td><td class="left">2.3.1.  Generation</td><td> </td><td class="right">2.3.1.  Generation</td><td class="lineno" valign="top"></td></tr>
377      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
378      <tr><td class="lineno" valign="top"></td><td class="left">   The principle behind entity-tags is that only the service author</td><td> </td><td class="right">   The principle behind entity-tags is that only the service author</td><td class="lineno" valign="top"></td></tr>
379      <tr><td class="lineno" valign="top"></td><td class="left">   knows the implementation of a resource well enough to select the most</td><td> </td><td class="right">   knows the implementation of a resource well enough to select the most</td><td class="lineno" valign="top"></td></tr>
380      <tr><td class="lineno" valign="top"></td><td class="left">   accurate and efficient validation mechanism for that resource, and</td><td> </td><td class="right">   accurate and efficient validation mechanism for that resource, and</td><td class="lineno" valign="top"></td></tr>
381      <tr><td class="lineno" valign="top"></td><td class="left">   that any such mechanism can be mapped to a simple sequence of octets</td><td> </td><td class="right">   that any such mechanism can be mapped to a simple sequence of octets</td><td class="lineno" valign="top"></td></tr>
382      <tr><td class="lineno" valign="top"></td><td class="left">   for easy comparison.  Since the value is opaque, there is no need for</td><td> </td><td class="right">   for easy comparison.  Since the value is opaque, there is no need for</td><td class="lineno" valign="top"></td></tr>
383      <tr><td class="lineno" valign="top"></td><td class="left">   the client to be aware of how each entity-tag is constructed.</td><td> </td><td class="right">   the client to be aware of how each entity-tag is constructed.</td><td class="lineno" valign="top"></td></tr>
384      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
385      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
386      <tr bgcolor="gray" ><td></td><th><a name="part-l7" /><small>skipping to change at</small><em> page 10, line 35</em></th><th> </th><th><a name="part-r7" /><small>skipping to change at</small><em> page 10, line 35</em></th><td></td></tr>
387      <tr><td class="lineno" valign="top"></td><td class="left">   determined, since the entity-tag's use in conditional requests and</td><td> </td><td class="right">   determined, since the entity-tag's use in conditional requests and</td><td class="lineno" valign="top"></td></tr>
388      <tr><td class="lineno" valign="top"></td><td class="left">   evaluating cache freshness ([Part6]) can result in a substantial</td><td> </td><td class="right">   evaluating cache freshness ([Part6]) can result in a substantial</td><td class="lineno" valign="top"></td></tr>
389      <tr><td class="lineno" valign="top"></td><td class="left">   reduction of HTTP network traffic and can be a significant factor in</td><td> </td><td class="right">   reduction of HTTP network traffic and can be a significant factor in</td><td class="lineno" valign="top"></td></tr>
390      <tr><td class="lineno" valign="top"></td><td class="left">   improving service scalability and reliability.</td><td> </td><td class="right">   improving service scalability and reliability.</td><td class="lineno" valign="top"></td></tr>
391      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
392      <tr><td class="lineno" valign="top"></td><td class="left">2.3.2.  Comparison</td><td> </td><td class="right">2.3.2.  Comparison</td><td class="lineno" valign="top"></td></tr>
393      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
394      <tr><td class="lineno" valign="top"></td><td class="left">   There are two entity-tag comparison functions, depending on whether</td><td> </td><td class="right">   There are two entity-tag comparison functions, depending on whether</td><td class="lineno" valign="top"></td></tr>
395      <tr><td class="lineno" valign="top"></td><td class="left">   the comparison context allows the use of weak validators or not:</td><td> </td><td class="right">   the comparison context allows the use of weak validators or not:</td><td class="lineno" valign="top"></td></tr>
396      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
397      <tr><td><a name="diff0025" /></td></tr>
398      <tr><td class="lineno" valign="top"></td><td class="lblock">   o  <span class="delete">The strong comparison function: in order to be considered equal,</span></td><td> </td><td class="rblock">   o  <span class="insert">Strong comparison: two entity-tags are equivalent if</span> both <span class="insert">are not</span></td><td class="lineno" valign="top"></td></tr>
399      <tr><td class="lineno" valign="top"></td><td class="lblock">      both <span class="delete">opaque-tags MUST be identical character-by-character,</span> and</td><td> </td><td class="rblock"><span class="insert">      weak</span> and <span class="insert">their opaque-tags match character-by-character.</span></td><td class="lineno" valign="top"></td></tr>
400      <tr><td class="lineno" valign="top"></td><td class="lblock">      <span class="delete">both MUST NOT be weak.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
401      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
402      <tr><td><a name="diff0026" /></td></tr>
403      <tr><td class="lineno" valign="top"></td><td class="lblock">   o  <span class="delete">The weak comparison function: in order to be considered equal,</span></td><td> </td><td class="rblock">   o  <span class="insert">Weak comparison: two entity-tags are equivalent if their opaque-</span></td><td class="lineno" valign="top"></td></tr>
404      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      both opaque-tags MUST be identical</span> character-by-character, <span class="delete">but</span></td><td> </td><td class="rblock"><span class="insert">      tags match</span> character-by-character, <span class="insert">regardless of</span> either or both</td><td class="lineno" valign="top"></td></tr>
405      <tr><td class="lineno" valign="top"></td><td class="lblock">      either or both <span class="delete">of them MAY be</span> tagged as <span class="delete">"weak" without affecting</span></td><td> </td><td class="rblock">      <span class="insert">being</span> tagged as <span class="insert">"weak".</span></td><td class="lineno" valign="top"></td></tr>
406      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      the result.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
407      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
408      <tr><td class="lineno" valign="top"></td><td class="left">   The example below shows the results for a set of entity-tag pairs,</td><td> </td><td class="right">   The example below shows the results for a set of entity-tag pairs,</td><td class="lineno" valign="top"></td></tr>
409      <tr><td class="lineno" valign="top"></td><td class="left">   and both the weak and strong comparison function results:</td><td> </td><td class="right">   and both the weak and strong comparison function results:</td><td class="lineno" valign="top"></td></tr>
410      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
411      <tr><td class="lineno" valign="top"></td><td class="left">   +--------+--------+-------------------+-----------------+</td><td> </td><td class="right">   +--------+--------+-------------------+-----------------+</td><td class="lineno" valign="top"></td></tr>
412      <tr><td class="lineno" valign="top"></td><td class="left">   | ETag 1 | ETag 2 | Strong Comparison | Weak Comparison |</td><td> </td><td class="right">   | ETag 1 | ETag 2 | Strong Comparison | Weak Comparison |</td><td class="lineno" valign="top"></td></tr>
413      <tr><td class="lineno" valign="top"></td><td class="left">   +--------+--------+-------------------+-----------------+</td><td> </td><td class="right">   +--------+--------+-------------------+-----------------+</td><td class="lineno" valign="top"></td></tr>
414      <tr><td class="lineno" valign="top"></td><td class="left">   | W/"1"  | W/"1"  | no match          | match           |</td><td> </td><td class="right">   | W/"1"  | W/"1"  | no match          | match           |</td><td class="lineno" valign="top"></td></tr>
415      <tr><td class="lineno" valign="top"></td><td class="left">   | W/"1"  | W/"2"  | no match          | no match        |</td><td> </td><td class="right">   | W/"1"  | W/"2"  | no match          | no match        |</td><td class="lineno" valign="top"></td></tr>
416      <tr><td class="lineno" valign="top"></td><td class="left">   | W/"1"  | "1"    | no match          | match           |</td><td> </td><td class="right">   | W/"1"  | "1"    | no match          | match           |</td><td class="lineno" valign="top"></td></tr>
417      <tr><td class="lineno" valign="top"></td><td class="left">   | "1"    | "1"    | match             | match           |</td><td> </td><td class="right">   | "1"    | "1"    | match             | match           |</td><td class="lineno" valign="top"></td></tr>
418      <tr><td class="lineno" valign="top"></td><td class="left">   +--------+--------+-------------------+-----------------+</td><td> </td><td class="right">   +--------+--------+-------------------+-----------------+</td><td class="lineno" valign="top"></td></tr>
419      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
420      <tr><td><a name="diff0027" /></td></tr>
421      <tr><td class="lineno" valign="top"></td><td class="lblock">2.3.3.  Example: Entity-tags <span class="delete">v</span>arying on Content-Negotiated Resources</td><td> </td><td class="rblock">2.3.3.  Example: Entity-tags <span class="insert">V</span>arying on Content-Negotiated Resources</td><td class="lineno" valign="top"></td></tr>
422      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
423      <tr><td class="lineno" valign="top"></td><td class="left">   Consider a resource that is subject to content negotiation (Section</td><td> </td><td class="right">   Consider a resource that is subject to content negotiation (Section</td><td class="lineno" valign="top"></td></tr>
424      <tr><td><a name="diff0028" /></td></tr>
425      <tr><td class="lineno" valign="top"></td><td class="lblock">   3.4 of [Part2]), and where the representations <span class="delete">returned upon</span> a GET</td><td> </td><td class="rblock">   3.4 of [Part2]), and where the representations <span class="insert">sent in response to</span> a</td><td class="lineno" valign="top"></td></tr>
426      <tr><td class="lineno" valign="top"></td><td class="lblock">   request vary based on the Accept-Encoding request header field</td><td> </td><td class="rblock">   GET request vary based on the Accept-Encoding request header field</td><td class="lineno" valign="top"></td></tr>
427      <tr><td class="lineno" valign="top"></td><td class="lblock">   (Section <span class="delete">6.3.4</span> of [Part2]):</td><td> </td><td class="rblock">   (Section <span class="insert">5.3.4</span> of [Part2]):</td><td class="lineno" valign="top"></td></tr>
428      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
429      <tr><td class="lineno" valign="top"></td><td class="left">   &gt;&gt; Request:</td><td> </td><td class="right">   &gt;&gt; Request:</td><td class="lineno" valign="top"></td></tr>
430      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
431      <tr><td class="lineno" valign="top"></td><td class="left">     GET /index HTTP/1.1</td><td> </td><td class="right">     GET /index HTTP/1.1</td><td class="lineno" valign="top"></td></tr>
432      <tr><td class="lineno" valign="top"></td><td class="left">     Host: www.example.com</td><td> </td><td class="right">     Host: www.example.com</td><td class="lineno" valign="top"></td></tr>
433      <tr><td class="lineno" valign="top"></td><td class="left">     Accept-Encoding: gzip</td><td> </td><td class="right">     Accept-Encoding: gzip</td><td class="lineno" valign="top"></td></tr>
434      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
435      <tr><td class="lineno" valign="top"></td><td class="left">   In this case, the response might or might not use the gzip content</td><td> </td><td class="right">   In this case, the response might or might not use the gzip content</td><td class="lineno" valign="top"></td></tr>
436      <tr><td class="lineno" valign="top"></td><td class="left">   coding.  If it does not, the response might look like:</td><td> </td><td class="right">   coding.  If it does not, the response might look like:</td><td class="lineno" valign="top"></td></tr>
437      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
438      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
439      <tr bgcolor="gray" ><td></td><th><a name="part-l8" /><small>skipping to change at</small><em> page 12, line 24</em></th><th> </th><th><a name="part-r8" /><small>skipping to change at</small><em> page 12, line 12</em></th><td></td></tr>
440      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
441      <tr><td class="lineno" valign="top"></td><td class="left">     ...binary data...</td><td> </td><td class="right">     ...binary data...</td><td class="lineno" valign="top"></td></tr>
442      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
443      <tr><td class="lineno" valign="top"></td><td class="left">      Note: Content codings are a property of the representation, so</td><td> </td><td class="right">      Note: Content codings are a property of the representation, so</td><td class="lineno" valign="top"></td></tr>
444      <tr><td class="lineno" valign="top"></td><td class="left">      therefore an entity-tag of an encoded representation has to be</td><td> </td><td class="right">      therefore an entity-tag of an encoded representation has to be</td><td class="lineno" valign="top"></td></tr>
445      <tr><td class="lineno" valign="top"></td><td class="left">      distinct from an unencoded representation to prevent conflicts</td><td> </td><td class="right">      distinct from an unencoded representation to prevent conflicts</td><td class="lineno" valign="top"></td></tr>
446      <tr><td class="lineno" valign="top"></td><td class="left">      during cache updates and range requests.  In contrast, transfer</td><td> </td><td class="right">      during cache updates and range requests.  In contrast, transfer</td><td class="lineno" valign="top"></td></tr>
447      <tr><td class="lineno" valign="top"></td><td class="left">      codings (Section 4 of [Part1]) apply only during message transfer</td><td> </td><td class="right">      codings (Section 4 of [Part1]) apply only during message transfer</td><td class="lineno" valign="top"></td></tr>
448      <tr><td class="lineno" valign="top"></td><td class="left">      and do not require distinct entity-tags.</td><td> </td><td class="right">      and do not require distinct entity-tags.</td><td class="lineno" valign="top"></td></tr>
449      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
450      <tr><td><a name="diff0029" /></td></tr>
451      <tr><td class="lineno" valign="top"></td><td class="lblock">2.4.  <span class="delete">Rules for </span>When to Use Entity-tags and Last-Modified Dates</td><td> </td><td class="rblock">2.4.  When to Use Entity-tags and Last-Modified Dates</td><td class="lineno" valign="top"></td></tr>
452      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
453      <tr><td class="lineno" valign="top"></td><td class="left">   We adopt a set of rules and recommendations for origin servers,</td><td> </td><td class="right">   We adopt a set of rules and recommendations for origin servers,</td><td class="lineno" valign="top"></td></tr>
454      <tr><td class="lineno" valign="top"></td><td class="left">   clients, and caches regarding when various validator types ought to</td><td> </td><td class="right">   clients, and caches regarding when various validator types ought to</td><td class="lineno" valign="top"></td></tr>
455      <tr><td class="lineno" valign="top"></td><td class="left">   be used, and for what purposes.</td><td> </td><td class="right">   be used, and for what purposes.</td><td class="lineno" valign="top"></td></tr>
456      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
457      <tr><td><a name="diff0030" /></td></tr>
458      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">HTTP/1.1 origin servers</span>:</td><td> </td><td class="rblock">   <span class="insert">In 200 (OK) responses to GET or HEAD, an origin server</span>:</td><td class="lineno" valign="top"></td></tr>
459      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
460      <tr><td class="lineno" valign="top"></td><td class="left">   o  SHOULD send an entity-tag validator unless it is not feasible to</td><td> </td><td class="right">   o  SHOULD send an entity-tag validator unless it is not feasible to</td><td class="lineno" valign="top"></td></tr>
461      <tr><td class="lineno" valign="top"></td><td class="left">      generate one.</td><td> </td><td class="right">      generate one.</td><td class="lineno" valign="top"></td></tr>
462      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
463      <tr><td class="lineno" valign="top"></td><td class="left">   o  MAY send a weak entity-tag instead of a strong entity-tag, if</td><td> </td><td class="right">   o  MAY send a weak entity-tag instead of a strong entity-tag, if</td><td class="lineno" valign="top"></td></tr>
464      <tr><td class="lineno" valign="top"></td><td class="left">      performance considerations support the use of weak entity-tags, or</td><td> </td><td class="right">      performance considerations support the use of weak entity-tags, or</td><td class="lineno" valign="top"></td></tr>
465      <tr><td class="lineno" valign="top"></td><td class="left">      if it is unfeasible to send a strong entity-tag.</td><td> </td><td class="right">      if it is unfeasible to send a strong entity-tag.</td><td class="lineno" valign="top"></td></tr>
466      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
467      <tr><td class="lineno" valign="top"></td><td class="left">   o  SHOULD send a Last-Modified value if it is feasible to send one.</td><td> </td><td class="right">   o  SHOULD send a Last-Modified value if it is feasible to send one.</td><td class="lineno" valign="top"></td></tr>
468      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
469      <tr><td><a name="diff0031" /></td></tr>
470      <tr><td class="lineno" valign="top"></td><td class="lblock">   In other words, the preferred behavior for an <span class="delete">HTTP/1.1</span> origin server</td><td> </td><td class="rblock">   In other words, the preferred behavior for an origin server is to</td><td class="lineno" valign="top"></td></tr>
471      <tr><td class="lineno" valign="top"></td><td class="lblock">   is to send both a strong entity-tag and a Last-Modified <span class="delete">value.</span></td><td> </td><td class="rblock">   send both a strong entity-tag and a Last-Modified <span class="insert">value in successful</span></td><td class="lineno" valign="top"></td></tr>
472      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   responses to a retrieval request.</span></td><td class="lineno" valign="top"></td></tr>
473      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
474      <tr><td><a name="diff0032" /></td></tr>
475      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">HTTP/1.1 clients</span>:</td><td> </td><td class="rblock">   <span class="insert">A client</span>:</td><td class="lineno" valign="top"></td></tr>
476      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
477      <tr><td class="lineno" valign="top"></td><td class="left">   o  MUST use that entity-tag in any cache-conditional request (using</td><td> </td><td class="right">   o  MUST use that entity-tag in any cache-conditional request (using</td><td class="lineno" valign="top"></td></tr>
478      <tr><td class="lineno" valign="top"></td><td class="left">      If-Match or If-None-Match) if an entity-tag has been provided by</td><td> </td><td class="right">      If-Match or If-None-Match) if an entity-tag has been provided by</td><td class="lineno" valign="top"></td></tr>
479      <tr><td class="lineno" valign="top"></td><td class="left">      the origin server.</td><td> </td><td class="right">      the origin server.</td><td class="lineno" valign="top"></td></tr>
480      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
481      <tr><td class="lineno" valign="top"></td><td class="left">   o  SHOULD use the Last-Modified value in non-subrange cache-</td><td> </td><td class="right">   o  SHOULD use the Last-Modified value in non-subrange cache-</td><td class="lineno" valign="top"></td></tr>
482      <tr><td class="lineno" valign="top"></td><td class="left">      conditional requests (using If-Modified-Since) if only a Last-</td><td> </td><td class="right">      conditional requests (using If-Modified-Since) if only a Last-</td><td class="lineno" valign="top"></td></tr>
483      <tr><td class="lineno" valign="top"></td><td class="left">      Modified value has been provided by the origin server.</td><td> </td><td class="right">      Modified value has been provided by the origin server.</td><td class="lineno" valign="top"></td></tr>
484      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
485      <tr><td class="lineno" valign="top"></td><td class="left">   o  MAY use the Last-Modified value in subrange cache-conditional</td><td> </td><td class="right">   o  MAY use the Last-Modified value in subrange cache-conditional</td><td class="lineno" valign="top"></td></tr>
486      <tr><td class="lineno" valign="top"></td><td class="left">      requests (using If-Unmodified-Since) if only a Last-Modified value</td><td> </td><td class="right">      requests (using If-Unmodified-Since) if only a Last-Modified value</td><td class="lineno" valign="top"></td></tr>
487      <tr><td class="lineno" valign="top"></td><td class="left">      has been provided by an HTTP/1.0 origin server.  The user agent</td><td> </td><td class="right">      has been provided by an HTTP/1.0 origin server.  The user agent</td><td class="lineno" valign="top"></td></tr>
488      <tr><td class="lineno" valign="top"></td><td class="left">      SHOULD provide a way to disable this, in case of difficulty.</td><td> </td><td class="right">      SHOULD provide a way to disable this, in case of difficulty.</td><td class="lineno" valign="top"></td></tr>
489      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
490      <tr><td class="lineno" valign="top"></td><td class="left">   o  SHOULD use both validators in cache-conditional requests if both</td><td> </td><td class="right">   o  SHOULD use both validators in cache-conditional requests if both</td><td class="lineno" valign="top"></td></tr>
491      <tr><td class="lineno" valign="top"></td><td class="left">      an entity-tag and a Last-Modified value have been provided by the</td><td> </td><td class="right">      an entity-tag and a Last-Modified value have been provided by the</td><td class="lineno" valign="top"></td></tr>
492      <tr><td class="lineno" valign="top"></td><td class="left">      origin server.  This allows both HTTP/1.0 and HTTP/1.1 caches to</td><td> </td><td class="right">      origin server.  This allows both HTTP/1.0 and HTTP/1.1 caches to</td><td class="lineno" valign="top"></td></tr>
493      <tr><td class="lineno" valign="top"></td><td class="left">      respond appropriately.</td><td> </td><td class="right">      respond appropriately.</td><td class="lineno" valign="top"></td></tr>
494      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
495      <tr><td><a name="diff0033" /></td></tr>
496      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">An HTTP/1.1 origin server, upon receiving a conditional request that</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
497      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   includes both a Last-Modified date (e.g., in an If-Modified-Since or</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
498      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   If-Unmodified-Since header field) and one or more entity-tags (e.g.,</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
499      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   in an If-Match, If-None-Match, or If-Range header field) as cache</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
500      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   validators, MUST NOT return a response status code of 304 (Not</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
501      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   Modified) unless doing so is consistent with all of the conditional</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
502      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   header fields in the request.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
503      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete"></span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
504      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   An HTTP/1.1 caching proxy, upon receiving a conditional request that</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
505      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   includes both a Last-Modified date and one or more entity-tags as</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
506      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   cache validators, MUST NOT return a locally cached response to the</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
507      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   client unless that cached response is consistent with all of the</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
508      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   conditional header fields in the request.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
509      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete"></span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
510      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      Note: The general principle behind these rules is that HTTP/1.1</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
511      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      servers and clients ought to transmit as much non-redundant</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
512      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      information as is available in their responses and requests.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
513      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      HTTP/1.1 systems receiving this information will make the most</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
514      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      conservative assumptions about the validators they receive.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
515      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete"></span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
516      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      HTTP/1.0 clients and caches might ignore entity-tags.  Generally,</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
517      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      last-modified values received or used by these systems will</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
518      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      support transparent and efficient caching, and so HTTP/1.1 origin</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
519      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      servers still ought to provide Last-Modified values.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
520      <tr><td class="lineno" valign="top"></td><td class="lblock">                                                                         </td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
521      <tr><td class="lineno" valign="top"></td><td class="left">3.  Precondition Header Fields</td><td> </td><td class="right">3.  Precondition Header Fields</td><td class="lineno" valign="top"></td></tr>
522      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
523      <tr><td class="lineno" valign="top"></td><td class="left">   This section defines the syntax and semantics of HTTP/1.1 header</td><td> </td><td class="right">   This section defines the syntax and semantics of HTTP/1.1 header</td><td class="lineno" valign="top"></td></tr>
524      <tr><td><a name="diff0034" /></td></tr>
525      <tr><td class="lineno" valign="top"></td><td class="lblock">   fields for applying preconditions on requests.  Section 5 defines the</td><td> </td><td class="rblock">   fields for applying preconditions on requests.  Section 5 defines</td><td class="lineno" valign="top"></td></tr>
526      <tr><td class="lineno" valign="top"></td><td class="lblock">   order of evaluation when more than one precondition is <span class="delete">present in a</span></td><td> </td><td class="rblock">   <span class="insert">when the preconditions are applied and</span> the order of evaluation when</td><td class="lineno" valign="top"></td></tr>
527      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   request.</span></td><td> </td><td class="rblock">   more than one precondition is <span class="insert">present.</span></td><td class="lineno" valign="top"></td></tr>
528      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
529      <tr><td class="lineno" valign="top"></td><td class="left">3.1.  If-Match</td><td> </td><td class="right">3.1.  If-Match</td><td class="lineno" valign="top"></td></tr>
530      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
531      <tr><td class="lineno" valign="top"></td><td class="left">   The "If-Match" header field can be used to make a request method</td><td> </td><td class="right">   The "If-Match" header field can be used to make a request method</td><td class="lineno" valign="top"></td></tr>
532      <tr><td class="lineno" valign="top"></td><td class="left">   conditional on the current existence or value of an entity-tag for</td><td> </td><td class="right">   conditional on the current existence or value of an entity-tag for</td><td class="lineno" valign="top"></td></tr>
533      <tr><td class="lineno" valign="top"></td><td class="left">   one or more representations of the target resource.</td><td> </td><td class="right">   one or more representations of the target resource.</td><td class="lineno" valign="top"></td></tr>
534      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
535      <tr><td class="lineno" valign="top"></td><td class="left">   If-Match is generally useful for resource update requests, such as</td><td> </td><td class="right">   If-Match is generally useful for resource update requests, such as</td><td class="lineno" valign="top"></td></tr>
536      <tr><td class="lineno" valign="top"></td><td class="left">   PUT requests, as a means for protecting against accidental overwrites</td><td> </td><td class="right">   PUT requests, as a means for protecting against accidental overwrites</td><td class="lineno" valign="top"></td></tr>
537      <tr><td class="lineno" valign="top"></td><td class="left">   when multiple clients are acting in parallel on the same resource</td><td> </td><td class="right">   when multiple clients are acting in parallel on the same resource</td><td class="lineno" valign="top"></td></tr>
538      <tr><td class="lineno" valign="top"></td><td class="left">   (i.e., the "lost update" problem).  An If-Match field-value of "*"</td><td> </td><td class="right">   (i.e., the "lost update" problem).  An If-Match field-value of "*"</td><td class="lineno" valign="top"></td></tr>
539      <tr><td class="lineno" valign="top"></td><td class="left">   places the precondition on the existence of any current</td><td> </td><td class="right">   places the precondition on the existence of any current</td><td class="lineno" valign="top"></td></tr>
540      <tr><td class="lineno" valign="top"></td><td class="left">   representation for the target resource.</td><td> </td><td class="right">   representation for the target resource.</td><td class="lineno" valign="top"></td></tr>
541      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
542      <tr><td class="lineno" valign="top"></td><td class="left">     If-Match = "*" / 1#entity-tag</td><td> </td><td class="right">     If-Match = "*" / 1#entity-tag</td><td class="lineno" valign="top"></td></tr>
543      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
544      <tr><td class="lineno" valign="top"></td><td class="left">   The If-Match condition is met if and only if any of the entity-tags</td><td> </td><td class="right">   The If-Match condition is met if and only if any of the entity-tags</td><td class="lineno" valign="top"></td></tr>
545      <tr><td class="lineno" valign="top"></td><td class="left">   listed in the If-Match field value match the entity-tag of the</td><td> </td><td class="right">   listed in the If-Match field value match the entity-tag of the</td><td class="lineno" valign="top"></td></tr>
546      <tr><td><a name="diff0035" /></td></tr>
547      <tr><td class="lineno" valign="top"></td><td class="lblock">   selected representation <span class="delete">for the target resource</span> (as per</td><td> </td><td class="rblock">   selected representation <span class="insert">using the weak comparison function</span> (as per</td><td class="lineno" valign="top"></td></tr>
548      <tr><td class="lineno" valign="top"></td><td class="left">   Section 2.3.2), or if "*" is given and any current representation</td><td> </td><td class="right">   Section 2.3.2), or if "*" is given and any current representation</td><td class="lineno" valign="top"></td></tr>
549      <tr><td class="lineno" valign="top"></td><td class="left">   exists for the target resource.</td><td> </td><td class="right">   exists for the target resource.</td><td class="lineno" valign="top"></td></tr>
550      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
551      <tr><td><a name="diff0036" /></td></tr>
552      <tr><td class="lineno" valign="top"></td><td class="lblock">   If the condition is met, the server MAY perform the request <span class="delete">method as</span></td><td> </td><td class="rblock">   If the condition is met, the server MAY perform the request <span class="insert">method.</span></td><td class="lineno" valign="top"></td></tr>
553      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   if the If-Match header field was not present.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
554      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
555      <tr><td class="lineno" valign="top"></td><td class="left">   Origin servers MUST NOT perform the requested method if the condition</td><td> </td><td class="right">   Origin servers MUST NOT perform the requested method if the condition</td><td class="lineno" valign="top"></td></tr>
556      <tr><td class="lineno" valign="top"></td><td class="left">   is not met; instead they MUST respond with the 412 (Precondition</td><td> </td><td class="right">   is not met; instead they MUST respond with the 412 (Precondition</td><td class="lineno" valign="top"></td></tr>
557      <tr><td class="lineno" valign="top"></td><td class="left">   Failed) status code.</td><td> </td><td class="right">   Failed) status code.</td><td class="lineno" valign="top"></td></tr>
558      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
559      <tr><td class="lineno" valign="top"></td><td class="left">   Proxy servers using a cached response as the selected representation</td><td> </td><td class="right">   Proxy servers using a cached response as the selected representation</td><td class="lineno" valign="top"></td></tr>
560      <tr><td class="lineno" valign="top"></td><td class="left">   MUST NOT perform the requested method if the condition is not met;</td><td> </td><td class="right">   MUST NOT perform the requested method if the condition is not met;</td><td class="lineno" valign="top"></td></tr>
561      <tr><td class="lineno" valign="top"></td><td class="left">   instead, they MUST forward the request towards the origin server.</td><td> </td><td class="right">   instead, they MUST forward the request towards the origin server.</td><td class="lineno" valign="top"></td></tr>
562      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
563      <tr><td><a name="diff0037" /></td></tr>
564      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">If the request would, without the If-Match header field, result in</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
565      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   anything other than a 2xx (Successful) or 412 (Precondition Failed)</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
566      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   status code, then the If-Match header field MUST be ignored.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
567      <tr><td class="lineno" valign="top"></td><td class="lblock">                                                                         </td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
568      <tr><td class="lineno" valign="top"></td><td class="left">   Examples:</td><td> </td><td class="right">   Examples:</td><td class="lineno" valign="top"></td></tr>
569      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
570      <tr><td class="lineno" valign="top"></td><td class="left">     If-Match: "xyzzy"</td><td> </td><td class="right">     If-Match: "xyzzy"</td><td class="lineno" valign="top"></td></tr>
571      <tr><td class="lineno" valign="top"></td><td class="left">     If-Match: "xyzzy", "r2d2xxxx", "c3piozzzz"</td><td> </td><td class="right">     If-Match: "xyzzy", "r2d2xxxx", "c3piozzzz"</td><td class="lineno" valign="top"></td></tr>
572      <tr><td class="lineno" valign="top"></td><td class="left">     If-Match: *</td><td> </td><td class="right">     If-Match: *</td><td class="lineno" valign="top"></td></tr>
573      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
574      <tr><td class="lineno" valign="top"></td><td class="left">3.2.  If-None-Match</td><td> </td><td class="right">3.2.  If-None-Match</td><td class="lineno" valign="top"></td></tr>
575      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
576      <tr><td class="lineno" valign="top"></td><td class="left">   The "If-None-Match" header field can be used to make a request method</td><td> </td><td class="right">   The "If-None-Match" header field can be used to make a request method</td><td class="lineno" valign="top"></td></tr>
577      <tr><td class="lineno" valign="top"></td><td class="left">   conditional on not matching any of the current entity-tag values for</td><td> </td><td class="right">   conditional on not matching any of the current entity-tag values for</td><td class="lineno" valign="top"></td></tr>
578      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
579      <tr bgcolor="gray" ><td></td><th><a name="part-l9" /><small>skipping to change at</small><em> page 15, line 18</em></th><th> </th><th><a name="part-r9" /><small>skipping to change at</small><em> page 14, line 31</em></th><td></td></tr>
580      <tr><td class="lineno" valign="top"></td><td class="left">   existing representation of the target resource when the client</td><td> </td><td class="right">   existing representation of the target resource when the client</td><td class="lineno" valign="top"></td></tr>
581      <tr><td class="lineno" valign="top"></td><td class="left">   believes that the resource does not have a current representation.</td><td> </td><td class="right">   believes that the resource does not have a current representation.</td><td class="lineno" valign="top"></td></tr>
582      <tr><td class="lineno" valign="top"></td><td class="left">   This is a variation on the "lost update" problem that might arise if</td><td> </td><td class="right">   This is a variation on the "lost update" problem that might arise if</td><td class="lineno" valign="top"></td></tr>
583      <tr><td class="lineno" valign="top"></td><td class="left">   more than one client attempts to create an initial representation for</td><td> </td><td class="right">   more than one client attempts to create an initial representation for</td><td class="lineno" valign="top"></td></tr>
584      <tr><td class="lineno" valign="top"></td><td class="left">   the target resource.</td><td> </td><td class="right">   the target resource.</td><td class="lineno" valign="top"></td></tr>
585      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
586      <tr><td class="lineno" valign="top"></td><td class="left">     If-None-Match = "*" / 1#entity-tag</td><td> </td><td class="right">     If-None-Match = "*" / 1#entity-tag</td><td class="lineno" valign="top"></td></tr>
587      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
588      <tr><td class="lineno" valign="top"></td><td class="left">   The If-None-Match condition is met if and only if none of the entity-</td><td> </td><td class="right">   The If-None-Match condition is met if and only if none of the entity-</td><td class="lineno" valign="top"></td></tr>
589      <tr><td class="lineno" valign="top"></td><td class="left">   tags listed in the If-None-Match field value match the entity-tag of</td><td> </td><td class="right">   tags listed in the If-None-Match field value match the entity-tag of</td><td class="lineno" valign="top"></td></tr>
590      <tr><td><a name="diff0038" /></td></tr>
591      <tr><td class="lineno" valign="top"></td><td class="lblock">   the selected representation <span class="delete">for</span> the <span class="delete">target resource</span> (as per</td><td> </td><td class="rblock">   the selected representation <span class="insert">using</span> the <span class="insert">weak comparison function</span> (as</td><td class="lineno" valign="top"></td></tr>
592      <tr><td class="lineno" valign="top"></td><td class="lblock">   Section 2.3.2), or if "*" is given and no current representation</td><td> </td><td class="rblock">   per Section 2.3.2), or if "*" is given and no current representation</td><td class="lineno" valign="top"></td></tr>
593      <tr><td class="lineno" valign="top"></td><td class="left">   exists for that resource.</td><td> </td><td class="right">   exists for that resource.</td><td class="lineno" valign="top"></td></tr>
594      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
595      <tr><td class="lineno" valign="top"></td><td class="left">   If the condition is not met, the server MUST NOT perform the</td><td> </td><td class="right">   If the condition is not met, the server MUST NOT perform the</td><td class="lineno" valign="top"></td></tr>
596      <tr><td class="lineno" valign="top"></td><td class="left">   requested method.  Instead, if the request method was GET or HEAD,</td><td> </td><td class="right">   requested method.  Instead, if the request method was GET or HEAD,</td><td class="lineno" valign="top"></td></tr>
597      <tr><td class="lineno" valign="top"></td><td class="left">   the server SHOULD respond with a 304 (Not Modified) status code,</td><td> </td><td class="right">   the server SHOULD respond with a 304 (Not Modified) status code,</td><td class="lineno" valign="top"></td></tr>
598      <tr><td class="lineno" valign="top"></td><td class="left">   including the cache-related header fields (particularly ETag) of the</td><td> </td><td class="right">   including the cache-related header fields (particularly ETag) of the</td><td class="lineno" valign="top"></td></tr>
599      <tr><td class="lineno" valign="top"></td><td class="left">   selected representation that has a matching entity-tag.  For all</td><td> </td><td class="right">   selected representation that has a matching entity-tag.  For all</td><td class="lineno" valign="top"></td></tr>
600      <tr><td class="lineno" valign="top"></td><td class="left">   other request methods, the server MUST respond with a 412</td><td> </td><td class="right">   other request methods, the server MUST respond with a 412</td><td class="lineno" valign="top"></td></tr>
601      <tr><td><a name="diff0039" /></td></tr>
602      <tr><td class="lineno" valign="top"></td><td class="lblock">   (Precondition Failed) status code.</td><td> </td><td class="rblock">   (Precondition Failed) status code<span class="insert"> when the condition is not met</span>.</td><td class="lineno" valign="top"></td></tr>
603      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
604      <tr><td class="lineno" valign="top"></td><td class="left">   If the condition is met, the server MAY perform the requested method</td><td> </td><td class="right">   If the condition is met, the server MAY perform the requested method</td><td class="lineno" valign="top"></td></tr>
605      <tr><td><a name="diff0040" /></td></tr>
606      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">as if the If-None-Match header field did not exist, but</span> MUST <span class="delete">also</span></td><td> </td><td class="rblock">   <span class="insert">and</span> MUST ignore any If-Modified-Since header field(s) in the request.</td><td class="lineno" valign="top"></td></tr>
607      <tr><td class="lineno" valign="top"></td><td class="lblock">   ignore any If-Modified-Since header field(s) in the request.  That</td><td> </td><td class="rblock">   That is, if no entity-tags match, then the server MUST NOT <span class="insert">send</span> a 304</td><td class="lineno" valign="top"></td></tr>
608      <tr><td class="lineno" valign="top"></td><td class="lblock">   is, if no entity-tags match, then the server MUST NOT <span class="delete">return</span> a 304</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
609      <tr><td class="lineno" valign="top"></td><td class="left">   (Not Modified) response.</td><td> </td><td class="right">   (Not Modified) response.</td><td class="lineno" valign="top"></td></tr>
610      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
611      <tr><td><a name="diff0041" /></td></tr>
612      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">If the request would, without the If-None-Match header field, result</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
613      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   in anything other than a 2xx (Successful) or 304 (Not Modified)</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
614      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   status code, then the If-None-Match header field MUST be ignored.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
615      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   (See Section 2.4 for a discussion of server behavior when both If-</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
616      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   Modified-Since and If-None-Match appear in the same request.)</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
617      <tr><td class="lineno" valign="top"></td><td class="lblock">                                                                         </td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
618      <tr><td class="lineno" valign="top"></td><td class="left">   Examples:</td><td> </td><td class="right">   Examples:</td><td class="lineno" valign="top"></td></tr>
619      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
620      <tr><td class="lineno" valign="top"></td><td class="left">     If-None-Match: "xyzzy"</td><td> </td><td class="right">     If-None-Match: "xyzzy"</td><td class="lineno" valign="top"></td></tr>
621      <tr><td class="lineno" valign="top"></td><td class="left">     If-None-Match: W/"xyzzy"</td><td> </td><td class="right">     If-None-Match: W/"xyzzy"</td><td class="lineno" valign="top"></td></tr>
622      <tr><td class="lineno" valign="top"></td><td class="left">     If-None-Match: "xyzzy", "r2d2xxxx", "c3piozzzz"</td><td> </td><td class="right">     If-None-Match: "xyzzy", "r2d2xxxx", "c3piozzzz"</td><td class="lineno" valign="top"></td></tr>
623      <tr><td class="lineno" valign="top"></td><td class="left">     If-None-Match: W/"xyzzy", W/"r2d2xxxx", W/"c3piozzzz"</td><td> </td><td class="right">     If-None-Match: W/"xyzzy", W/"r2d2xxxx", W/"c3piozzzz"</td><td class="lineno" valign="top"></td></tr>
624      <tr><td class="lineno" valign="top"></td><td class="left">     If-None-Match: *</td><td> </td><td class="right">     If-None-Match: *</td><td class="lineno" valign="top"></td></tr>
625      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
626      <tr><td class="lineno" valign="top"></td><td class="left">3.3.  If-Modified-Since</td><td> </td><td class="right">3.3.  If-Modified-Since</td><td class="lineno" valign="top"></td></tr>
627      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
628      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
629      <tr bgcolor="gray" ><td></td><th><a name="part-l10" /><small>skipping to change at</small><em> page 16, line 28</em></th><th> </th><th><a name="part-r10" /><small>skipping to change at</small><em> page 15, line 34</em></th><td></td></tr>
630      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
631      <tr><td class="lineno" valign="top"></td><td class="left">   A GET method with an If-Modified-Since header field and no Range</td><td> </td><td class="right">   A GET method with an If-Modified-Since header field and no Range</td><td class="lineno" valign="top"></td></tr>
632      <tr><td class="lineno" valign="top"></td><td class="left">   header field requests that the selected representation be transferred</td><td> </td><td class="right">   header field requests that the selected representation be transferred</td><td class="lineno" valign="top"></td></tr>
633      <tr><td class="lineno" valign="top"></td><td class="left">   only if it has been modified since the date given by the If-Modified-</td><td> </td><td class="right">   only if it has been modified since the date given by the If-Modified-</td><td class="lineno" valign="top"></td></tr>
634      <tr><td class="lineno" valign="top"></td><td class="left">   Since header field.  The algorithm for determining this includes the</td><td> </td><td class="right">   Since header field.  The algorithm for determining this includes the</td><td class="lineno" valign="top"></td></tr>
635      <tr><td class="lineno" valign="top"></td><td class="left">   following cases:</td><td> </td><td class="right">   following cases:</td><td class="lineno" valign="top"></td></tr>
636      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
637      <tr><td class="lineno" valign="top"></td><td class="left">   1.  If the request would normally result in anything other than a 200</td><td> </td><td class="right">   1.  If the request would normally result in anything other than a 200</td><td class="lineno" valign="top"></td></tr>
638      <tr><td class="lineno" valign="top"></td><td class="left">       (OK) status code, or if the passed If-Modified-Since date is</td><td> </td><td class="right">       (OK) status code, or if the passed If-Modified-Since date is</td><td class="lineno" valign="top"></td></tr>
639      <tr><td class="lineno" valign="top"></td><td class="left">       invalid, the response is exactly the same as for a normal GET.  A</td><td> </td><td class="right">       invalid, the response is exactly the same as for a normal GET.  A</td><td class="lineno" valign="top"></td></tr>
640      <tr><td><a name="diff0042" /></td></tr>
641      <tr><td class="lineno" valign="top"></td><td class="lblock">       date <span class="delete">which</span> is later than the server's current time is invalid.</td><td> </td><td class="rblock">       date <span class="insert">that</span> is later than the server's current time is invalid.</td><td class="lineno" valign="top"></td></tr>
642      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
643      <tr><td class="lineno" valign="top"></td><td class="left">   2.  If the selected representation has been modified since the If-</td><td> </td><td class="right">   2.  If the selected representation has been modified since the If-</td><td class="lineno" valign="top"></td></tr>
644      <tr><td class="lineno" valign="top"></td><td class="left">       Modified-Since date, the response is exactly the same as for a</td><td> </td><td class="right">       Modified-Since date, the response is exactly the same as for a</td><td class="lineno" valign="top"></td></tr>
645      <tr><td class="lineno" valign="top"></td><td class="left">       normal GET.</td><td> </td><td class="right">       normal GET.</td><td class="lineno" valign="top"></td></tr>
646      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
647      <tr><td class="lineno" valign="top"></td><td class="left">   3.  If the selected representation has not been modified since a</td><td> </td><td class="right">   3.  If the selected representation has not been modified since a</td><td class="lineno" valign="top"></td></tr>
648      <tr><td><a name="diff0043" /></td></tr>
649      <tr><td class="lineno" valign="top"></td><td class="lblock">       valid If-Modified-Since date, the server SHOULD <span class="delete">return</span> a 304 (Not</td><td> </td><td class="rblock">       valid If-Modified-Since date, the server SHOULD <span class="insert">send</span> a 304 (Not</td><td class="lineno" valign="top"></td></tr>
650      <tr><td class="lineno" valign="top"></td><td class="left">       Modified) response.</td><td> </td><td class="right">       Modified) response.</td><td class="lineno" valign="top"></td></tr>
651      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
652      <tr><td><a name="diff0044" /></td></tr>
653      <tr><td class="lineno" valign="top"></td><td class="lblock">   The <span class="delete">purpose</span> of this feature <span class="delete">is</span> to allow efficient updates of cached</td><td> </td><td class="rblock">   The <span class="insert">two purposes</span> of this feature <span class="insert">are</span> to allow efficient updates of</td><td class="lineno" valign="top"></td></tr>
654      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">information</span> with a minimum amount of transaction <span class="delete">overhead.</span></td><td> </td><td class="rblock">   cached <span class="insert">information,</span> with a minimum amount of transaction <span class="insert">overhead,</span></td><td class="lineno" valign="top"></td></tr>
655      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete"></span></td><td> </td><td class="rblock"><span class="insert">   and to limit</span> the <span class="insert">scope</span> of <span class="insert">a web traversal to resources that have</span></td><td class="lineno" valign="top"></td></tr>
656      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      Note: The Range header field modifies</span> the <span class="delete">meaning of If-Modified-</span></td><td> </td><td class="rblock"><span class="insert">   recently changed.</span></td><td class="lineno" valign="top"></td></tr>
657      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      Since; see Section 5.4</span> of <span class="delete">[Part5] for full details.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
658      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
659      <tr><td><a name="diff0045" /></td></tr>
660      <tr><td class="lineno" valign="top"></td><td class="lblock">      <span class="delete">Note: If-Modified-Since times are interpreted by</span> the <span class="delete">server, whose</span></td><td> </td><td class="rblock">   <span class="insert">When used for cache updates, a cache will typically use</span> the <span class="insert">value of</span></td><td class="lineno" valign="top"></td></tr>
661      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      clock might not be</span> synchronized with the <span class="delete">client.</span></td><td> </td><td class="rblock"><span class="insert">   the cached message's Last-Modified field to generate the field value</span></td><td class="lineno" valign="top"></td></tr>
662      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   of If-Modified-Since.  This behavior is most interoperable for cases</span></td><td class="lineno" valign="top"></td></tr>
663      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   where clocks are poorly</span> synchronized <span class="insert">or when the server has chosen to</span></td><td class="lineno" valign="top"></td></tr>
664      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   only honor exact timestamp matches (due to a problem</span> with <span class="insert">Last-</span></td><td class="lineno" valign="top"></td></tr>
665      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   Modified dates that appear to go "back in time" when the origin</span></td><td class="lineno" valign="top"></td></tr>
666      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   server's clock is corrected or a representation is restored from an</span></td><td class="lineno" valign="top"></td></tr>
667      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   archived backup).  However, caches occasionally generate the field</span></td><td class="lineno" valign="top"></td></tr>
668      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   value based on other data, such as the Date header field of the</span></td><td class="lineno" valign="top"></td></tr>
669      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   cached message or</span> the <span class="insert">local clock time that the message was received,</span></td><td class="lineno" valign="top"></td></tr>
670      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   particularly when the cached message does not contain a Last-Modified</span></td><td class="lineno" valign="top"></td></tr>
671      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   field.</span></td><td class="lineno" valign="top"></td></tr>
672      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
673      <tr><td><a name="diff0046" /></td></tr>
674      <tr><td class="lineno" valign="top"></td><td class="lblock">      <span class="delete">Note:</span> When <span class="delete">handling an If-Modified-Since header field, some</span></td><td> </td><td class="rblock">   When <span class="insert">used</span> for <span class="insert">limiting the scope of retrieval</span> to a <span class="insert">recent time</span></td><td class="lineno" valign="top"></td></tr>
675      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      servers will use an exact date comparison function, rather than a</span></td><td> </td><td class="rblock"><span class="insert">   window, a user agent will generate</span> an <span class="insert">If-Modified-Since field value</span></td><td class="lineno" valign="top"></td></tr>
676      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      less-than function,</span> for <span class="delete">deciding whether</span> to <span class="delete">send</span> a <span class="delete">304 (Not</span></td><td> </td><td class="rblock"><span class="insert">   based on either its own local clock or a Date</span> header field received</td><td class="lineno" valign="top"></td></tr>
677      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      Modified) response.  To get best results when sending</span> an <span class="delete">If-</span></td><td> </td><td class="rblock">   <span class="insert">from the server during</span> a <span class="insert">past run.  Origin servers that choose an</span></td><td class="lineno" valign="top"></td></tr>
678      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      Modified-Since</span> header field <span class="delete">for cache validation, clients are</span></td><td> </td><td class="rblock"><span class="insert">   exact timestamp match based on the selected representation's</span> Last-</td><td class="lineno" valign="top"></td></tr>
679      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      advised to use the exact date string</span> received <span class="delete">in</span> a <span class="delete">previous</span> Last-</td><td> </td><td class="rblock">   Modified field <span class="insert">will not be able to help the user agent limit its data</span></td><td class="lineno" valign="top"></td></tr>
680      <tr><td class="lineno" valign="top"></td><td class="lblock">      Modified <span class="delete">header</span> field <span class="delete">whenever possible.</span></td><td> </td><td class="rblock"><span class="insert">   transfers to only those changed during the specified window.</span></td><td class="lineno" valign="top"></td></tr>
681      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
682      <tr><td class="lineno" valign="top"></td><td class="left">      Note: If a client uses an arbitrary date in the If-Modified-Since</td><td> </td><td class="right">      Note: If a client uses an arbitrary date in the If-Modified-Since</td><td class="lineno" valign="top"></td></tr>
683      <tr><td><a name="diff0047" /></td></tr>
684      <tr><td class="lineno" valign="top"></td><td class="lblock">      header field instead of a date taken from <span class="delete">the</span> Last-Modified header</td><td> </td><td class="rblock">      header field instead of a date taken from <span class="insert">a</span> Last-Modified <span class="insert">or Date</span></td><td class="lineno" valign="top"></td></tr>
685      <tr><td class="lineno" valign="top"></td><td class="lblock">      field <span class="delete">for</span> the <span class="delete">same request,</span> the client <span class="delete">needs</span> to be aware that <span class="delete">this</span></td><td> </td><td class="rblock">      header field <span class="insert">from</span> the <span class="insert">origin server,</span> the client <span class="insert">ought</span> to be aware</td><td class="lineno" valign="top"></td></tr>
686      <tr><td class="lineno" valign="top"></td><td class="lblock">      date <span class="delete">is</span> interpreted <span class="delete">in</span> the server's understanding of time.</td><td> </td><td class="rblock">      that <span class="insert">its</span> date <span class="insert">will be</span> interpreted <span class="insert">according to</span> the server's</td><td class="lineno" valign="top"></td></tr>
687      <tr><td class="lineno" valign="top"></td><td class="lblock">      <span class="delete">Unsynchronized clocks and rounding problems, due to the different</span></td><td> </td><td class="rblock">      understanding of time.</td><td class="lineno" valign="top"></td></tr>
688      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      encodings of time between the client and server, are concerns.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
689      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      This includes the possibility of race conditions if the document</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
690      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      has changed between the time it was first requested and the If-</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
691      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      Modified-Since date of a subsequent request, and the possibility</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
692      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      of clock-skew-related problems if the If-Modified-Since date is</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
693      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      derived from the client's clock without correction to the server's</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
694      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      clock.  Corrections for different time bases between client and</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
695      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">      server are at best approximate due to network latency.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
696      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
697      <tr><td class="lineno" valign="top"></td><td class="left">3.4.  If-Unmodified-Since</td><td> </td><td class="right">3.4.  If-Unmodified-Since</td><td class="lineno" valign="top"></td></tr>
698      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
699      <tr><td class="lineno" valign="top"></td><td class="left">   The "If-Unmodified-Since" header field can be used to make a request</td><td> </td><td class="right">   The "If-Unmodified-Since" header field can be used to make a request</td><td class="lineno" valign="top"></td></tr>
700      <tr><td class="lineno" valign="top"></td><td class="left">   method conditional by modification date: if the selected</td><td> </td><td class="right">   method conditional by modification date: if the selected</td><td class="lineno" valign="top"></td></tr>
701      <tr><td class="lineno" valign="top"></td><td class="left">   representation has been modified since the time specified in this</td><td> </td><td class="right">   representation has been modified since the time specified in this</td><td class="lineno" valign="top"></td></tr>
702      <tr><td class="lineno" valign="top"></td><td class="left">   field, then the server MUST NOT perform the requested operation and</td><td> </td><td class="right">   field, then the server MUST NOT perform the requested operation and</td><td class="lineno" valign="top"></td></tr>
703      <tr><td class="lineno" valign="top"></td><td class="left">   MUST instead respond with the 412 (Precondition Failed) status code.</td><td> </td><td class="right">   MUST instead respond with the 412 (Precondition Failed) status code.</td><td class="lineno" valign="top"></td></tr>
704      <tr><td class="lineno" valign="top"></td><td class="left">   If the selected representation has not been modified since the time</td><td> </td><td class="right">   If the selected representation has not been modified since the time</td><td class="lineno" valign="top"></td></tr>
705      <tr><td><a name="diff0048" /></td></tr>
706      <tr><td class="lineno" valign="top"></td><td class="lblock">   specified in this field, the server <span class="delete">SHOULD</span> perform the <span class="delete">request method</span></td><td> </td><td class="rblock">   specified in this field, the server <span class="insert">MAY</span> perform the <span class="insert">request.</span></td><td class="lineno" valign="top"></td></tr>
707      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   as if the If-Unmodified-Since header field were not present.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
708      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
709      <tr><td class="lineno" valign="top"></td><td class="left">     If-Unmodified-Since = HTTP-date</td><td> </td><td class="right">     If-Unmodified-Since = HTTP-date</td><td class="lineno" valign="top"></td></tr>
710      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
711      <tr><td class="lineno" valign="top"></td><td class="left">   An example of the field is:</td><td> </td><td class="right">   An example of the field is:</td><td class="lineno" valign="top"></td></tr>
712      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
713      <tr><td class="lineno" valign="top"></td><td class="left">     If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT</td><td> </td><td class="right">     If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT</td><td class="lineno" valign="top"></td></tr>
714      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
715      <tr><td><a name="diff0049" /></td></tr>
716      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">If a request normally (i.e., in absence of the If-Unmodified-Since</span></td><td> </td><td class="rblock">   <span class="insert">A server MUST ignore</span> the If-Unmodified-Since header field <span class="insert">if</span> the</td><td class="lineno" valign="top"></td></tr>
717      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   header field) would result in anything other than a 2xx (Successful)</span></td><td> </td><td class="rblock">   <span class="insert">received value</span> is <span class="insert">not a valid HTTP-date.</span></td><td class="lineno" valign="top"></td></tr>
718      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   or 412 (Precondition Failed) status code,</span> the If-Unmodified-Since</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
719      <tr><td class="lineno" valign="top"></td><td class="lblock">   header field <span class="delete">SHOULD be ignored.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
720      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete"></span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
721      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   If</span> the <span class="delete">specified date</span> is <span class="delete">invalid, the header field MUST be ignored.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
722      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
723      <tr><td class="lineno" valign="top"></td><td class="left">3.5.  If-Range</td><td> </td><td class="right">3.5.  If-Range</td><td class="lineno" valign="top"></td></tr>
724      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
725      <tr><td class="lineno" valign="top"></td><td class="left">   The "If-Range" header field provides a special conditional request</td><td> </td><td class="right">   The "If-Range" header field provides a special conditional request</td><td class="lineno" valign="top"></td></tr>
726      <tr><td class="lineno" valign="top"></td><td class="left">   mechanism that is similar to If-Match and If-Unmodified-Since but</td><td> </td><td class="right">   mechanism that is similar to If-Match and If-Unmodified-Since but</td><td class="lineno" valign="top"></td></tr>
727      <tr><td><a name="diff0050" /></td></tr>
728      <tr><td class="lineno" valign="top"></td><td class="lblock">   specific to <span class="delete">HTTP</span> range requests.  If-Range is defined in Section <span class="delete">5.3</span></td><td> </td><td class="rblock">   specific to range requests.  If-Range is defined in Section <span class="insert">3.2</span> of</td><td class="lineno" valign="top"></td></tr>
729      <tr><td class="lineno" valign="top"></td><td class="lblock">   of [Part5].</td><td> </td><td class="rblock">   [Part5].</td><td class="lineno" valign="top"></td></tr>
730      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
731      <tr><td class="lineno" valign="top"></td><td class="left">4.  Status Code Definitions</td><td> </td><td class="right">4.  Status Code Definitions</td><td class="lineno" valign="top"></td></tr>
732      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
733      <tr><td class="lineno" valign="top"></td><td class="left">4.1.  304 Not Modified</td><td> </td><td class="right">4.1.  304 Not Modified</td><td class="lineno" valign="top"></td></tr>
734      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
735      <tr><td><a name="diff0051" /></td></tr>
736      <tr><td class="lineno" valign="top"></td><td class="lblock">   The 304 status code indicates that a conditional GET request has been</td><td> </td><td class="rblock">   The 304 <span class="insert">(Not Modified)</span> status code indicates that a conditional GET</td><td class="lineno" valign="top"></td></tr>
737      <tr><td class="lineno" valign="top"></td><td class="lblock">   received and would have resulted in a 200 (OK) response if it were</td><td> </td><td class="rblock">   request has been received and would have resulted in a 200 (OK)</td><td class="lineno" valign="top"></td></tr>
738      <tr><td class="lineno" valign="top"></td><td class="lblock">   not for the fact that the condition has evaluated to false.  In other</td><td> </td><td class="rblock">   response if it were not for the fact that the condition has evaluated</td><td class="lineno" valign="top"></td></tr>
739      <tr><td class="lineno" valign="top"></td><td class="lblock">   words, there is no need for the server to transfer a representation</td><td> </td><td class="rblock">   to false.  In other words, there is no need for the server to</td><td class="lineno" valign="top"></td></tr>
740      <tr><td class="lineno" valign="top"></td><td class="lblock">   of the target resource because the <span class="delete">client's</span> request indicates that <span class="delete">it</span></td><td> </td><td class="rblock">   transfer a representation of the target resource because the request</td><td class="lineno" valign="top"></td></tr>
741      <tr><td class="lineno" valign="top"></td><td class="lblock">   already has a valid <span class="delete">representation, as indicated by</span> the <span class="delete">304 response</span></td><td> </td><td class="rblock">   indicates that <span class="insert">the client, which made the request conditional,</span></td><td class="lineno" valign="top"></td></tr>
742      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   header fields, and</span> is therefore redirecting the client to make use of</td><td> </td><td class="rblock">   already has a valid <span class="insert">representation;</span> the <span class="insert">server</span> is therefore</td><td class="lineno" valign="top"></td></tr>
743      <tr><td class="lineno" valign="top"></td><td class="lblock">   that stored representation as if it were the payload of a 200</td><td> </td><td class="rblock">   redirecting the client to make use of that stored representation as</td><td class="lineno" valign="top"></td></tr>
744      <tr><td class="lineno" valign="top"></td><td class="lblock">   response.  <span class="delete">The 304 response MUST NOT contain a message-body, and thus</span></td><td> </td><td class="rblock">   if it were the payload of a 200 <span class="insert">(OK)</span> response.</td><td class="lineno" valign="top"></td></tr>
745      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   is always terminated by the first empty line after the header fields.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
746      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
747      <tr><td><a name="diff0052" /></td></tr>
748      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">A</span> 304 response MUST <span class="delete">include a Date header field (Section 8.1.1.2</span> of</td><td> </td><td class="rblock">   <span class="insert">The server generating a</span> 304 response MUST <span class="insert">generate any</span> of the</td><td class="lineno" valign="top"></td></tr>
749      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">[Part2]) unless</span> the <span class="delete">origin server does not have a clock</span> that <span class="delete">can</span></td><td> </td><td class="rblock">   <span class="insert">following header fields</span> that <span class="insert">would have been sent in</span> a 200 (OK)</td><td class="lineno" valign="top"></td></tr>
750      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   provide a reasonable approximation of the current time.  If</span> a 200</td><td> </td><td class="rblock">   response to the same <span class="insert">request:</span> Cache-Control, Content-Location, ETag,</td><td class="lineno" valign="top"></td></tr>
751      <tr><td class="lineno" valign="top"></td><td class="lblock">   (OK) response to the same <span class="delete">request would have included any of the</span></td><td> </td><td class="rblock">   Expires, <span class="insert">and Vary.</span></td><td class="lineno" valign="top"></td></tr>
752      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   header fields</span> Cache-Control, Content-Location, ETag, Expires, <span class="delete">or</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
753      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   Vary, then those same header fields MUST be sent in a 304 response.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
754      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
755      <tr><td class="lineno" valign="top"></td><td class="left">   Since the goal of a 304 response is to minimize information transfer</td><td> </td><td class="right">   Since the goal of a 304 response is to minimize information transfer</td><td class="lineno" valign="top"></td></tr>
756      <tr><td><a name="diff0053" /></td></tr>
757      <tr><td class="lineno" valign="top"></td><td class="lblock">   when the recipient already has one or more cached representations,</td><td> </td><td class="rblock">   when the recipient already has one or more cached representations, <span class="insert">a</span></td><td class="lineno" valign="top"></td></tr>
758      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">the response</span> SHOULD NOT <span class="delete">include</span> representation metadata other than</td><td> </td><td class="rblock"><span class="insert">   sender</span> SHOULD NOT <span class="insert">generate</span> representation metadata other than the</td><td class="lineno" valign="top"></td></tr>
759      <tr><td class="lineno" valign="top"></td><td class="lblock">   the above listed fields unless said metadata exists for the purpose</td><td> </td><td class="rblock">   above listed fields unless said metadata exists for the purpose of</td><td class="lineno" valign="top"></td></tr>
760      <tr><td class="lineno" valign="top"></td><td class="lblock">   of guiding cache updates (e.g., <span class="delete">future HTTP extensions).</span></td><td> </td><td class="rblock">   guiding cache updates (e.g., <span class="insert">Last-Modified might be useful if the</span></td><td class="lineno" valign="top"></td></tr>
761      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   response does not have an ETag field).</span></td><td class="lineno" valign="top"></td></tr>
762      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
763      <tr><td><a name="diff0054" /></td></tr>
764      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">If the recipient of</span> a <span class="delete">304 response does not have</span> a <span class="delete">cached</span></td><td> </td><td class="rblock">   <span class="insert">Requirements on</span> a <span class="insert">cache that receives</span> a 304 <span class="insert">response are defined in</span></td><td class="lineno" valign="top"></td></tr>
765      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   representation corresponding to the entity-tag indicated by the 304</span></td><td> </td><td class="rblock"><span class="insert">   Section 4.2.1 of [Part6].</span>  If <span class="insert">the</span> conditional request originated with</td><td class="lineno" valign="top"></td></tr>
766      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   response, then the recipient MUST NOT use the</span> 304 <span class="delete">to update its own</span></td><td> </td><td class="rblock">   an outbound client, such as a user agent with its own cache sending a</td><td class="lineno" valign="top"></td></tr>
767      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   cache.</span>  If <span class="delete">this</span> conditional request originated with an outbound</td><td> </td><td class="rblock">   conditional GET to a shared proxy, then the <span class="insert">proxy SHOULD forward the</span></td><td class="lineno" valign="top"></td></tr>
768      <tr><td class="lineno" valign="top"></td><td class="lblock">   client, such as a user agent with its own cache sending a conditional</td><td> </td><td class="rblock">   304 response to that client.</td><td class="lineno" valign="top"></td></tr>
769      <tr><td class="lineno" valign="top"></td><td class="lblock">   GET to a shared proxy, then the 304 response <span class="delete">MAY be forwarded</span> to that</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
770      <tr><td class="lineno" valign="top"></td><td class="lblock">   client.  <span class="delete">Otherwise, the recipient MUST disregard the 304 response and</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
771      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   repeat the request without any preconditions.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
772      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
773      <tr><td><a name="diff0055" /></td></tr>
774      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">If a cache uses a received</span> 304 response <span class="delete">to update</span> a <span class="delete">cache entry, the</span></td><td> </td><td class="rblock">   <span class="insert">A</span> 304 response <span class="insert">cannot contain</span> a <span class="insert">message-body; it is always terminated</span></td><td class="lineno" valign="top"></td></tr>
775      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   cache MUST update</span> the <span class="delete">entry to reflect any new field values given in</span></td><td> </td><td class="rblock"><span class="insert">   by</span> the <span class="insert">first empty line after</span> the <span class="insert">header fields.</span></td><td class="lineno" valign="top"></td></tr>
776      <tr><td class="lineno" valign="top"></td><td class="lblock">   the <span class="delete">response.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
777      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
778      <tr><td class="lineno" valign="top"></td><td class="left">4.2.  412 Precondition Failed</td><td> </td><td class="right">4.2.  412 Precondition Failed</td><td class="lineno" valign="top"></td></tr>
779      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
780      <tr><td><a name="diff0056" /></td></tr>
781      <tr><td class="lineno" valign="top"></td><td class="lblock">   The 412 status code indicates that one or more preconditions given in</td><td> </td><td class="rblock">   The 412 <span class="insert">(Precondition Failed)</span> status code indicates that one or more</td><td class="lineno" valign="top"></td></tr>
782      <tr><td class="lineno" valign="top"></td><td class="lblock">   the request header fields evaluated to false when tested on the</td><td> </td><td class="rblock">   preconditions given in the request header fields evaluated to false</td><td class="lineno" valign="top"></td></tr>
783      <tr><td class="lineno" valign="top"></td><td class="lblock">   server.  This response code allows the client to place preconditions</td><td> </td><td class="rblock">   when tested on the server.  This response code allows the client to</td><td class="lineno" valign="top"></td></tr>
784      <tr><td class="lineno" valign="top"></td><td class="lblock">   on the current resource state (its current representations and</td><td> </td><td class="rblock">   place preconditions on the current resource state (its current</td><td class="lineno" valign="top"></td></tr>
785      <tr><td class="lineno" valign="top"></td><td class="lblock">   metadata) and thus prevent the request method from being applied if</td><td> </td><td class="rblock">   representations and metadata) and thus prevent the request method</td><td class="lineno" valign="top"></td></tr>
786      <tr><td class="lineno" valign="top"></td><td class="lblock">   the target resource is in an unexpected state.</td><td> </td><td class="rblock">   from being applied if the target resource is in an unexpected state.</td><td class="lineno" valign="top"></td></tr>
787      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
788      <tr><td><a name="diff0057" /></td></tr>
789      <tr><td class="lineno" valign="top"></td><td class="lblock">5.  Precedence</td><td> </td><td class="rblock">5.  <span class="insert">Evaluation and</span> Precedence</td><td class="lineno" valign="top"></td></tr>
790      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">                                                                         </td><td class="lineno" valign="top"></td></tr>
791      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   <span class="insert">For each conditional request, a server MUST evaluate the request</span></td><td class="lineno" valign="top"></td></tr>
792      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   preconditions after it has successfully performed its normal request</span></td><td class="lineno" valign="top"></td></tr>
793      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   checks (i.e., just before it would perform the action associated with</span></td><td class="lineno" valign="top"></td></tr>
794      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   the request method).  Preconditions are ignored if the server</span></td><td class="lineno" valign="top"></td></tr>
795      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   determines that an error or redirect response applies before they are</span></td><td class="lineno" valign="top"></td></tr>
796      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   evaluated.  Otherwise, the evaluation depends on both the method</span></td><td class="lineno" valign="top"></td></tr>
797      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   semantics and the choice of conditional.</span></td><td class="lineno" valign="top"></td></tr>
798      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
799      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   A conditional request header field that is designed specifically for</span></td><td class="lineno" valign="top"></td></tr>
800      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   cache validation, which includes If-None-Match and If-Modified-Since</span></td><td class="lineno" valign="top"></td></tr>
801      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   when used in a GET or HEAD request, allows cached representations to</span></td><td class="lineno" valign="top"></td></tr>
802      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   be refreshed without repeatedly transferring data already held by the</span></td><td class="lineno" valign="top"></td></tr>
803      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   client.  Evaluating to false is thus an indication that the client</span></td><td class="lineno" valign="top"></td></tr>
804      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   can continue to use its local copy of the selected representation, as</span></td><td class="lineno" valign="top"></td></tr>
805      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   indicated by the server generating a 304 (Not Modified) response that</span></td><td class="lineno" valign="top"></td></tr>
806      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   includes only those header fields useful for refreshing the cached</span></td><td class="lineno" valign="top"></td></tr>
807      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   representation.</span></td><td class="lineno" valign="top"></td></tr>
808      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
809      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   All other conditionals are intended to signal failure when the</span></td><td class="lineno" valign="top"></td></tr>
810      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   precondition evaluates to false.  For example, an If-Match</span></td><td class="lineno" valign="top"></td></tr>
811      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   conditional sent with a state-changing method (e.g., POST, PUT,</span></td><td class="lineno" valign="top"></td></tr>
812      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   DELETE) is intended to prevent the request from taking effect on the</span></td><td class="lineno" valign="top"></td></tr>
813      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   target resource if the resource state does not match the expected</span></td><td class="lineno" valign="top"></td></tr>
814      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   state.  In other words, evaluating the condition to false means that</span></td><td class="lineno" valign="top"></td></tr>
815      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   the resource has been changed by some other client, perhaps by</span></td><td class="lineno" valign="top"></td></tr>
816      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   another user attempting to edit the same resource, and thus</span></td><td class="lineno" valign="top"></td></tr>
817      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   preventing the request from being applied saves the client from</span></td><td class="lineno" valign="top"></td></tr>
818      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   overwriting some other client's work.  This result is indicated by</span></td><td class="lineno" valign="top"></td></tr>
819      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   the server generating a 412 (Precondition Failed) response.</span></td><td class="lineno" valign="top"></td></tr>
820      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
821      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   The conditional request header fields defined by this specification</span></td><td class="lineno" valign="top"></td></tr>
822      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   are ignored for request methods that never involve the selection or</span></td><td class="lineno" valign="top"></td></tr>
823      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   modification of a selected representation (e.g., CONNECT, OPTIONS,</span></td><td class="lineno" valign="top"></td></tr>
824      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   and TRACE).  Other conditional request header fields, defined by</span></td><td class="lineno" valign="top"></td></tr>
825      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   extensions to HTTP, might place conditions on the state of the target</span></td><td class="lineno" valign="top"></td></tr>
826      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   resource in general, or on a group of resources.  For instance, the</span></td><td class="lineno" valign="top"></td></tr>
827      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   If header field in WebDAV can make a request conditional on various</span></td><td class="lineno" valign="top"></td></tr>
828      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   aspects (such as locks) of multiple resources ([RFC4918], Section</span></td><td class="lineno" valign="top"></td></tr>
829      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   10.4).</span></td><td class="lineno" valign="top"></td></tr>
830      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
831      <tr><td class="lineno" valign="top"></td><td class="left">   When more than one conditional request header field is present in a</td><td> </td><td class="right">   When more than one conditional request header field is present in a</td><td class="lineno" valign="top"></td></tr>
832      <tr><td class="lineno" valign="top"></td><td class="left">   request, the order in which the fields are evaluated becomes</td><td> </td><td class="right">   request, the order in which the fields are evaluated becomes</td><td class="lineno" valign="top"></td></tr>
833      <tr><td class="lineno" valign="top"></td><td class="left">   important.  In practice, the fields defined in this document are</td><td> </td><td class="right">   important.  In practice, the fields defined in this document are</td><td class="lineno" valign="top"></td></tr>
834      <tr><td class="lineno" valign="top"></td><td class="left">   consistently implemented in a single, logical order, due to the fact</td><td> </td><td class="right">   consistently implemented in a single, logical order, due to the fact</td><td class="lineno" valign="top"></td></tr>
835      <tr><td class="lineno" valign="top"></td><td class="left">   that entity tags are presumed to be more accurate than date</td><td> </td><td class="right">   that entity tags are presumed to be more accurate than date</td><td class="lineno" valign="top"></td></tr>
836      <tr><td class="lineno" valign="top"></td><td class="left">   validators.  For example, the only reason to send both If-Modified-</td><td> </td><td class="right">   validators.  For example, the only reason to send both If-Modified-</td><td class="lineno" valign="top"></td></tr>
837      <tr><td class="lineno" valign="top"></td><td class="left">   Since and If-None-Match in the same GET request is to support</td><td> </td><td class="right">   Since and If-None-Match in the same GET request is to support</td><td class="lineno" valign="top"></td></tr>
838      <tr><td class="lineno" valign="top"></td><td class="left">   intermediary caches that might not have implemented If-None-Match, so</td><td> </td><td class="right">   intermediary caches that might not have implemented If-None-Match, so</td><td class="lineno" valign="top"></td></tr>
839      <tr><td class="lineno" valign="top"></td><td class="left">   it makes sense to ignore the If-Modified-Since when entity tags are</td><td> </td><td class="right">   it makes sense to ignore the If-Modified-Since when entity tags are</td><td class="lineno" valign="top"></td></tr>
840      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
841      <tr bgcolor="gray" ><td></td><th><a name="part-l11" /><small>skipping to change at</small><em> page 19, line 41</em></th><th> </th><th><a name="part-r11" /><small>skipping to change at</small><em> page 19, line 27</em></th><td></td></tr>
842      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
843      <tr><td class="lineno" valign="top"></td><td class="left">       *  if false, respond 412 (Precondition Failed)</td><td> </td><td class="right">       *  if false, respond 412 (Precondition Failed)</td><td class="lineno" valign="top"></td></tr>
844      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
845      <tr><td class="lineno" valign="top"></td><td class="left">   2.  When If-Match is not present and If-Unmodified-Since is present,</td><td> </td><td class="right">   2.  When If-Match is not present and If-Unmodified-Since is present,</td><td class="lineno" valign="top"></td></tr>
846      <tr><td class="lineno" valign="top"></td><td class="left">       evaluate it:</td><td> </td><td class="right">       evaluate it:</td><td class="lineno" valign="top"></td></tr>
847      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
848      <tr><td class="lineno" valign="top"></td><td class="left">       *  if true, continue to step 3</td><td> </td><td class="right">       *  if true, continue to step 3</td><td class="lineno" valign="top"></td></tr>
849      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
850      <tr><td class="lineno" valign="top"></td><td class="left">       *  if false, respond 412 (Precondition Failed)</td><td> </td><td class="right">       *  if false, respond 412 (Precondition Failed)</td><td class="lineno" valign="top"></td></tr>
851      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
852      <tr><td><a name="diff0058" /></td></tr>
853      <tr><td class="lineno" valign="top"></td><td class="lblock">   3.  When <span class="delete">the method</span> is <span class="delete">GET and both Range and If-Range are</span> present,</td><td> </td><td class="rblock">   3.  When <span class="insert">If-None-Match</span> is present, evaluate it:</td><td class="lineno" valign="top"></td></tr>
854      <tr><td class="lineno" valign="top"></td><td class="lblock">       evaluate it:</td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
855      <tr><td class="lineno" valign="top"></td><td class="lblock">                                                                         </td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
856      <tr><td class="lineno" valign="top"></td><td class="lblock">       <span class="delete">*  if the validator matches, respond 206 (Partial Content)</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
857      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete"></span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
858      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">       *  if the validator does not match, respond 200 (OK)</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
859      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
860      <tr><td><a name="diff0059" /></td></tr>
861      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">4.  When If-None-Match is present, evaluate it:</span></td><td> </td><td class="rblock">   <span class="insert">    *  if true, continue to step 5</span></td><td class="lineno" valign="top"></td></tr>
862      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
863      <tr><td><a name="diff0060" /></td></tr>
864      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">       *  if true, all conditions are met</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
865      <tr><td class="lineno" valign="top"></td><td class="left">       *  if false for GET/HEAD, respond 304 (Not Modified)</td><td> </td><td class="right">       *  if false for GET/HEAD, respond 304 (Not Modified)</td><td class="lineno" valign="top"></td></tr>
866      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
867      <tr><td class="lineno" valign="top"></td><td class="left">       *  if false for other methods, respond 412 (Precondition Failed)</td><td> </td><td class="right">       *  if false for other methods, respond 412 (Precondition Failed)</td><td class="lineno" valign="top"></td></tr>
868      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
869      <tr><td><a name="diff0061" /></td></tr>
870      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">5</span>.  When the method is GET or HEAD, If-None-Match is not present, and</td><td> </td><td class="rblock">   <span class="insert">4</span>.  When the method is GET or HEAD, If-None-Match is not present, and</td><td class="lineno" valign="top"></td></tr>
871      <tr><td class="lineno" valign="top"></td><td class="left">       If-Modified-Since is present, evaluate it:</td><td> </td><td class="right">       If-Modified-Since is present, evaluate it:</td><td class="lineno" valign="top"></td></tr>
872      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
873      <tr><td><a name="diff0062" /></td></tr>
874      <tr><td class="lineno" valign="top"></td><td class="lblock">       *  if true, <span class="delete">all conditions are met</span></td><td> </td><td class="rblock">       *  if true, <span class="insert">continue to step 5</span></td><td class="lineno" valign="top"></td></tr>
875      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
876      <tr><td class="lineno" valign="top"></td><td class="left">       *  if false, respond 304 (Not Modified)</td><td> </td><td class="right">       *  if false, respond 304 (Not Modified)</td><td class="lineno" valign="top"></td></tr>
877      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
878      <tr><td><a name="diff0063" /></td></tr>
879      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   <span class="insert">5.  When the method is GET and both Range and If-Range are present,</span></td><td class="lineno" valign="top"></td></tr>
880      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">       evaluate If-Range:</span></td><td class="lineno" valign="top"></td></tr>
881      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
882      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">       *  if the validator matches and the Range specification is</span></td><td class="lineno" valign="top"></td></tr>
883      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">          applicable to the selected representation, respond 206</span></td><td class="lineno" valign="top"></td></tr>
884      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">          (Partial Content) [Part5]</span></td><td class="lineno" valign="top"></td></tr>
885      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
886      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   6.  Otherwise,</span></td><td class="lineno" valign="top"></td></tr>
887      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
888      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">       *  all conditions are met, so perform the requested action and</span></td><td class="lineno" valign="top"></td></tr>
889      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">          respond according to its success or failure.</span></td><td class="lineno" valign="top"></td></tr>
890      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">                                                                         </td><td class="lineno" valign="top"></td></tr>
891      <tr><td class="lineno" valign="top"></td><td class="left">   Any extension to HTTP/1.1 that defines additional conditional request</td><td> </td><td class="right">   Any extension to HTTP/1.1 that defines additional conditional request</td><td class="lineno" valign="top"></td></tr>
892      <tr><td class="lineno" valign="top"></td><td class="left">   header fields ought to define its own expectations regarding the</td><td> </td><td class="right">   header fields ought to define its own expectations regarding the</td><td class="lineno" valign="top"></td></tr>
893      <tr><td class="lineno" valign="top"></td><td class="left">   order for evaluating such fields in relation to those defined in this</td><td> </td><td class="right">   order for evaluating such fields in relation to those defined in this</td><td class="lineno" valign="top"></td></tr>
894      <tr><td class="lineno" valign="top"></td><td class="left">   document and other conditionals that might be found in practice.</td><td> </td><td class="right">   document and other conditionals that might be found in practice.</td><td class="lineno" valign="top"></td></tr>
895      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
896      <tr><td class="lineno" valign="top"></td><td class="left">6.  IANA Considerations</td><td> </td><td class="right">6.  IANA Considerations</td><td class="lineno" valign="top"></td></tr>
897      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
898      <tr><td class="lineno" valign="top"></td><td class="left">6.1.  Status Code Registration</td><td> </td><td class="right">6.1.  Status Code Registration</td><td class="lineno" valign="top"></td></tr>
899      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
900      <tr><td class="lineno" valign="top"></td><td class="left">   The HTTP Status Code Registry located at</td><td> </td><td class="right">   The HTTP Status Code Registry located at</td><td class="lineno" valign="top"></td></tr>
901      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
902      <tr bgcolor="gray" ><td></td><th><a name="part-l12" /><small>skipping to change at</small><em> page 20, line 39</em></th><th> </th><th><a name="part-r12" /><small>skipping to change at</small><em> page 20, line 29</em></th><td></td></tr>
903      <tr><td class="lineno" valign="top"></td><td class="left">   | Value | Description         | Reference   |</td><td> </td><td class="right">   | Value | Description         | Reference   |</td><td class="lineno" valign="top"></td></tr>
904      <tr><td class="lineno" valign="top"></td><td class="left">   +-------+---------------------+-------------+</td><td> </td><td class="right">   +-------+---------------------+-------------+</td><td class="lineno" valign="top"></td></tr>
905      <tr><td class="lineno" valign="top"></td><td class="left">   | 304   | Not Modified        | Section 4.1 |</td><td> </td><td class="right">   | 304   | Not Modified        | Section 4.1 |</td><td class="lineno" valign="top"></td></tr>
906      <tr><td class="lineno" valign="top"></td><td class="left">   | 412   | Precondition Failed | Section 4.2 |</td><td> </td><td class="right">   | 412   | Precondition Failed | Section 4.2 |</td><td class="lineno" valign="top"></td></tr>
907      <tr><td class="lineno" valign="top"></td><td class="left">   +-------+---------------------+-------------+</td><td> </td><td class="right">   +-------+---------------------+-------------+</td><td class="lineno" valign="top"></td></tr>
908      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
909      <tr><td class="lineno" valign="top"></td><td class="left">6.2.  Header Field Registration</td><td> </td><td class="right">6.2.  Header Field Registration</td><td class="lineno" valign="top"></td></tr>
910      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
911      <tr><td class="lineno" valign="top"></td><td class="left">   The Message Header Field Registry located at &lt;http://www.iana.org/</td><td> </td><td class="right">   The Message Header Field Registry located at &lt;http://www.iana.org/</td><td class="lineno" valign="top"></td></tr>
912      <tr><td class="lineno" valign="top"></td><td class="left">   assignments/message-headers/message-header-index.html&gt; shall be</td><td> </td><td class="right">   assignments/message-headers/message-header-index.html&gt; shall be</td><td class="lineno" valign="top"></td></tr>
913      <tr><td><a name="diff0064" /></td></tr>
914      <tr><td class="lineno" valign="top"></td><td class="lblock">   updated with the permanent registrations below (see [<span class="delete">RFC3864</span>]):</td><td> </td><td class="rblock">   updated with the permanent registrations below (see [<span class="insert">BCP90</span>]):</td><td class="lineno" valign="top"></td></tr>
915      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
916      <tr><td class="lineno" valign="top"></td><td class="left">   +---------------------+----------+----------+-------------+</td><td> </td><td class="right">   +---------------------+----------+----------+-------------+</td><td class="lineno" valign="top"></td></tr>
917      <tr><td class="lineno" valign="top"></td><td class="left">   | Header Field Name   | Protocol | Status   | Reference   |</td><td> </td><td class="right">   | Header Field Name   | Protocol | Status   | Reference   |</td><td class="lineno" valign="top"></td></tr>
918      <tr><td class="lineno" valign="top"></td><td class="left">   +---------------------+----------+----------+-------------+</td><td> </td><td class="right">   +---------------------+----------+----------+-------------+</td><td class="lineno" valign="top"></td></tr>
919      <tr><td class="lineno" valign="top"></td><td class="left">   | ETag                | http     | standard | Section 2.3 |</td><td> </td><td class="right">   | ETag                | http     | standard | Section 2.3 |</td><td class="lineno" valign="top"></td></tr>
920      <tr><td class="lineno" valign="top"></td><td class="left">   | If-Match            | http     | standard | Section 3.1 |</td><td> </td><td class="right">   | If-Match            | http     | standard | Section 3.1 |</td><td class="lineno" valign="top"></td></tr>
921      <tr><td class="lineno" valign="top"></td><td class="left">   | If-Modified-Since   | http     | standard | Section 3.3 |</td><td> </td><td class="right">   | If-Modified-Since   | http     | standard | Section 3.3 |</td><td class="lineno" valign="top"></td></tr>
922      <tr><td class="lineno" valign="top"></td><td class="left">   | If-None-Match       | http     | standard | Section 3.2 |</td><td> </td><td class="right">   | If-None-Match       | http     | standard | Section 3.2 |</td><td class="lineno" valign="top"></td></tr>
923      <tr><td class="lineno" valign="top"></td><td class="left">   | If-Unmodified-Since | http     | standard | Section 3.4 |</td><td> </td><td class="right">   | If-Unmodified-Since | http     | standard | Section 3.4 |</td><td class="lineno" valign="top"></td></tr>
924      <tr><td class="lineno" valign="top"></td><td class="left">   | Last-Modified       | http     | standard | Section 2.2 |</td><td> </td><td class="right">   | Last-Modified       | http     | standard | Section 2.2 |</td><td class="lineno" valign="top"></td></tr>
925      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
926      <tr bgcolor="gray" ><td></td><th><a name="part-l13" /><small>skipping to change at</small><em> page 21, line 4</em></th><th> </th><th><a name="part-r13" /><small>skipping to change at</small><em> page 20, line 41</em></th><td></td></tr>
927      <tr><td class="lineno" valign="top"></td><td class="left">   +---------------------+----------+----------+-------------+</td><td> </td><td class="right">   +---------------------+----------+----------+-------------+</td><td class="lineno" valign="top"></td></tr>
928      <tr><td class="lineno" valign="top"></td><td class="left">   | Header Field Name   | Protocol | Status   | Reference   |</td><td> </td><td class="right">   | Header Field Name   | Protocol | Status   | Reference   |</td><td class="lineno" valign="top"></td></tr>
929      <tr><td class="lineno" valign="top"></td><td class="left">   +---------------------+----------+----------+-------------+</td><td> </td><td class="right">   +---------------------+----------+----------+-------------+</td><td class="lineno" valign="top"></td></tr>
930      <tr><td class="lineno" valign="top"></td><td class="left">   | ETag                | http     | standard | Section 2.3 |</td><td> </td><td class="right">   | ETag                | http     | standard | Section 2.3 |</td><td class="lineno" valign="top"></td></tr>
931      <tr><td class="lineno" valign="top"></td><td class="left">   | If-Match            | http     | standard | Section 3.1 |</td><td> </td><td class="right">   | If-Match            | http     | standard | Section 3.1 |</td><td class="lineno" valign="top"></td></tr>
932      <tr><td class="lineno" valign="top"></td><td class="left">   | If-Modified-Since   | http     | standard | Section 3.3 |</td><td> </td><td class="right">   | If-Modified-Since   | http     | standard | Section 3.3 |</td><td class="lineno" valign="top"></td></tr>
933      <tr><td class="lineno" valign="top"></td><td class="left">   | If-None-Match       | http     | standard | Section 3.2 |</td><td> </td><td class="right">   | If-None-Match       | http     | standard | Section 3.2 |</td><td class="lineno" valign="top"></td></tr>
934      <tr><td class="lineno" valign="top"></td><td class="left">   | If-Unmodified-Since | http     | standard | Section 3.4 |</td><td> </td><td class="right">   | If-Unmodified-Since | http     | standard | Section 3.4 |</td><td class="lineno" valign="top"></td></tr>
935      <tr><td class="lineno" valign="top"></td><td class="left">   | Last-Modified       | http     | standard | Section 2.2 |</td><td> </td><td class="right">   | Last-Modified       | http     | standard | Section 2.2 |</td><td class="lineno" valign="top"></td></tr>
936      <tr><td class="lineno" valign="top"></td><td class="left">   +---------------------+----------+----------+-------------+</td><td> </td><td class="right">   +---------------------+----------+----------+-------------+</td><td class="lineno" valign="top"></td></tr>
937      <tr><td><a name="diff0065" /></td></tr>
938      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">                                                                         </span></td><td class="lineno" valign="top"></td></tr>
939      <tr><td class="lineno" valign="top"></td><td class="left">   The change controller is: "IETF (iesg@ietf.org) - Internet</td><td> </td><td class="right">   The change controller is: "IETF (iesg@ietf.org) - Internet</td><td class="lineno" valign="top"></td></tr>
940      <tr><td class="lineno" valign="top"></td><td class="left">   Engineering Task Force".</td><td> </td><td class="right">   Engineering Task Force".</td><td class="lineno" valign="top"></td></tr>
941      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
942      <tr><td class="lineno" valign="top"></td><td class="left">7.  Security Considerations</td><td> </td><td class="right">7.  Security Considerations</td><td class="lineno" valign="top"></td></tr>
943      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
944      <tr><td><a name="diff0066" /></td></tr>
945      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">No additional</span> security <span class="delete">considerations have been identified beyond</span></td><td> </td><td class="rblock">   <span class="insert">This section is meant to inform developers, information providers,</span></td><td class="lineno" valign="top"></td></tr>
946      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   those applicable</span> to <span class="delete">HTTP in</span> general <span class="delete">[Part1].</span></td><td> </td><td class="rblock"><span class="insert">   and users of known</span> security <span class="insert">concerns specific</span> to <span class="insert">the HTTP/1.1</span></td><td class="lineno" valign="top"></td></tr>
947      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   conditional request mechanisms.  More</span> general <span class="insert">security considerations</span></td><td class="lineno" valign="top"></td></tr>
948      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   are addressed in HTTP messaging [Part1] and semantics [Part2].</span></td><td class="lineno" valign="top"></td></tr>
949      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
950      <tr><td class="lineno" valign="top"></td><td class="left">   The validators defined by this specification are not intended to</td><td> </td><td class="right">   The validators defined by this specification are not intended to</td><td class="lineno" valign="top"></td></tr>
951      <tr><td class="lineno" valign="top"></td><td class="left">   ensure the validity of a representation, guard against malicious</td><td> </td><td class="right">   ensure the validity of a representation, guard against malicious</td><td class="lineno" valign="top"></td></tr>
952      <tr><td class="lineno" valign="top"></td><td class="left">   changes, or detect man-in-the-middle attacks.  At best, they enable</td><td> </td><td class="right">   changes, or detect man-in-the-middle attacks.  At best, they enable</td><td class="lineno" valign="top"></td></tr>
953      <tr><td class="lineno" valign="top"></td><td class="left">   more efficient cache updates and optimistic concurrent writes when</td><td> </td><td class="right">   more efficient cache updates and optimistic concurrent writes when</td><td class="lineno" valign="top"></td></tr>
954      <tr><td class="lineno" valign="top"></td><td class="left">   all participants are behaving nicely.  At worst, the conditions will</td><td> </td><td class="right">   all participants are behaving nicely.  At worst, the conditions will</td><td class="lineno" valign="top"></td></tr>
955      <tr><td class="lineno" valign="top"></td><td class="left">   fail and the client will receive a response that is no more harmful</td><td> </td><td class="right">   fail and the client will receive a response that is no more harmful</td><td class="lineno" valign="top"></td></tr>
956      <tr><td class="lineno" valign="top"></td><td class="left">   than an HTTP exchange without conditional requests.</td><td> </td><td class="right">   than an HTTP exchange without conditional requests.</td><td class="lineno" valign="top"></td></tr>
957      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
958      <tr><td><a name="diff0067" /></td></tr>
959      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   <span class="insert">An entity-tag can be abused in ways that create privacy risks.  For</span></td><td class="lineno" valign="top"></td></tr>
960      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   example, a site might deliberately construct a semantically invalid</span></td><td class="lineno" valign="top"></td></tr>
961      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   entity-tag that is unique to the user or user agent, send it in a</span></td><td class="lineno" valign="top"></td></tr>
962      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   cacheable response with a long freshness time, and then read that</span></td><td class="lineno" valign="top"></td></tr>
963      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   entity-tag in later conditional requests as a means of re-identifying</span></td><td class="lineno" valign="top"></td></tr>
964      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   that user or user agent.  Such an identifying tag would become a</span></td><td class="lineno" valign="top"></td></tr>
965      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   persistent identifier for as long as the user agent retained the</span></td><td class="lineno" valign="top"></td></tr>
966      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   original cache entry.  User agents that cache representations ought</span></td><td class="lineno" valign="top"></td></tr>
967      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   to ensure that the cache is cleared or replaced whenever the user</span></td><td class="lineno" valign="top"></td></tr>
968      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   performs privacy-maintaining actions, such as clearing stored cookies</span></td><td class="lineno" valign="top"></td></tr>
969      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   or changing to a private browsing mode.</span></td><td class="lineno" valign="top"></td></tr>
970      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">                                                                         </td><td class="lineno" valign="top"></td></tr>
971      <tr><td class="lineno" valign="top"></td><td class="left">8.  Acknowledgments</td><td> </td><td class="right">8.  Acknowledgments</td><td class="lineno" valign="top"></td></tr>
972      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
973      <tr><td class="lineno" valign="top"></td><td class="left">   See Section 9 of [Part1].</td><td> </td><td class="right">   See Section 9 of [Part1].</td><td class="lineno" valign="top"></td></tr>
974      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
975      <tr><td class="lineno" valign="top"></td><td class="left">9.  References</td><td> </td><td class="right">9.  References</td><td class="lineno" valign="top"></td></tr>
976      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
977      <tr><td class="lineno" valign="top"></td><td class="left">9.1.  Normative References</td><td> </td><td class="right">9.1.  Normative References</td><td class="lineno" valign="top"></td></tr>
978      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
979      <tr><td class="lineno" valign="top"></td><td class="left">   [Part1]    Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer</td><td> </td><td class="right">   [Part1]    Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer</td><td class="lineno" valign="top"></td></tr>
980      <tr><td class="lineno" valign="top"></td><td class="left">              Protocol (HTTP/1.1): Message Syntax and Routing",</td><td> </td><td class="right">              Protocol (HTTP/1.1): Message Syntax and Routing",</td><td class="lineno" valign="top"></td></tr>
981      <tr><td><a name="diff0068" /></td></tr>
982      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">draft-ietf-httpbis-p1-messaging-21</span> (work in progress),</td><td> </td><td class="rblock">              <span class="insert">draft-ietf-httpbis-p1-messaging-22</span> (work in progress),</td><td class="lineno" valign="top"></td></tr>
983      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">October 2012.</span></td><td> </td><td class="rblock">              <span class="insert">February 2013.</span></td><td class="lineno" valign="top"></td></tr>
984      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
985      <tr><td class="lineno" valign="top"></td><td class="left">   [Part2]    Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer</td><td> </td><td class="right">   [Part2]    Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer</td><td class="lineno" valign="top"></td></tr>
986      <tr><td class="lineno" valign="top"></td><td class="left">              Protocol (HTTP/1.1): Semantics and Content",</td><td> </td><td class="right">              Protocol (HTTP/1.1): Semantics and Content",</td><td class="lineno" valign="top"></td></tr>
987      <tr><td><a name="diff0069" /></td></tr>
988      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">draft-ietf-httpbis-p2-semantics-21</span> (work in progress),</td><td> </td><td class="rblock">              <span class="insert">draft-ietf-httpbis-p2-semantics-22</span> (work in progress),</td><td class="lineno" valign="top"></td></tr>
989      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">October 2012.</span></td><td> </td><td class="rblock">              <span class="insert">February 2013.</span></td><td class="lineno" valign="top"></td></tr>
990      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
991      <tr><td class="lineno" valign="top"></td><td class="left">   [Part5]    Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,</td><td> </td><td class="right">   [Part5]    Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,</td><td class="lineno" valign="top"></td></tr>
992      <tr><td class="lineno" valign="top"></td><td class="left">              "Hypertext Transfer Protocol (HTTP/1.1): Range Requests",</td><td> </td><td class="right">              "Hypertext Transfer Protocol (HTTP/1.1): Range Requests",</td><td class="lineno" valign="top"></td></tr>
993      <tr><td><a name="diff0070" /></td></tr>
994      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">draft-ietf-httpbis-p5-range-21</span> (work in progress),</td><td> </td><td class="rblock">              <span class="insert">draft-ietf-httpbis-p5-range-22</span> (work in progress),</td><td class="lineno" valign="top"></td></tr>
995      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">October 2012.</span></td><td> </td><td class="rblock">              <span class="insert">February 2013.</span></td><td class="lineno" valign="top"></td></tr>
996      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
997      <tr><td class="lineno" valign="top"></td><td class="left">   [Part6]    Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,</td><td> </td><td class="right">   [Part6]    Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,</td><td class="lineno" valign="top"></td></tr>
998      <tr><td class="lineno" valign="top"></td><td class="left">              Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",</td><td> </td><td class="right">              Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",</td><td class="lineno" valign="top"></td></tr>
999      <tr><td><a name="diff0071" /></td></tr>
1000      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">draft-ietf-httpbis-p6-cache-21</span> (work in progress),</td><td> </td><td class="rblock">              <span class="insert">draft-ietf-httpbis-p6-cache-22</span> (work in progress),</td><td class="lineno" valign="top"></td></tr>
1001      <tr><td class="lineno" valign="top"></td><td class="lblock">              <span class="delete">October 2012.</span></td><td> </td><td class="rblock">              <span class="insert">February 2013.</span></td><td class="lineno" valign="top"></td></tr>
1002      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1003      <tr><td class="lineno" valign="top"></td><td class="left">   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate</td><td> </td><td class="right">   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate</td><td class="lineno" valign="top"></td></tr>
1004      <tr><td class="lineno" valign="top"></td><td class="left">              Requirement Levels", BCP 14, RFC 2119, March 1997.</td><td> </td><td class="right">              Requirement Levels", BCP 14, RFC 2119, March 1997.</td><td class="lineno" valign="top"></td></tr>
1005      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1006      <tr><td class="lineno" valign="top"></td><td class="left">   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax</td><td> </td><td class="right">   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax</td><td class="lineno" valign="top"></td></tr>
1007      <tr><td class="lineno" valign="top"></td><td class="left">              Specifications: ABNF", STD 68, RFC 5234, January 2008.</td><td> </td><td class="right">              Specifications: ABNF", STD 68, RFC 5234, January 2008.</td><td class="lineno" valign="top"></td></tr>
1008      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1009      <tr><td class="lineno" valign="top"></td><td class="left">9.2.  Informative References</td><td> </td><td class="right">9.2.  Informative References</td><td class="lineno" valign="top"></td></tr>
1010      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1011      <tr><td><a name="diff0072" /></td></tr>
1012      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   <span class="insert">[BCP90]    Klyne, G., Nottingham, M., and J. Mogul, "Registration</span></td><td class="lineno" valign="top"></td></tr>
1013      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">              Procedures for Message Header Fields", BCP 90, RFC 3864,</span></td><td class="lineno" valign="top"></td></tr>
1014      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">              September 2004.</span></td><td class="lineno" valign="top"></td></tr>
1015      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">                                                                         </td><td class="lineno" valign="top"></td></tr>
1016      <tr><td class="lineno" valign="top"></td><td class="left">   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,</td><td> </td><td class="right">   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,</td><td class="lineno" valign="top"></td></tr>
1017      <tr><td class="lineno" valign="top"></td><td class="left">              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext</td><td> </td><td class="right">              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext</td><td class="lineno" valign="top"></td></tr>
1018      <tr><td class="lineno" valign="top"></td><td class="left">              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.</td><td> </td><td class="right">              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.</td><td class="lineno" valign="top"></td></tr>
1019      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1020      <tr><td><a name="diff0073" /></td></tr>
1021      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">[RFC3864]  Klyne, G., Nottingham, M., and J. Mogul, "Registration</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
1022      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">              Procedures for Message Header Fields", BCP 90, RFC 3864,</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
1023      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">              September 2004.</span></td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
1024      <tr><td class="lineno" valign="top"></td><td class="lblock">                                                                         </td><td> </td><td class="rblock"></td><td class="lineno" valign="top"></td></tr>
1025      <tr><td class="lineno" valign="top"></td><td class="left">   [RFC4918]  Dusseault, L., Ed., "HTTP Extensions for Web Distributed</td><td> </td><td class="right">   [RFC4918]  Dusseault, L., Ed., "HTTP Extensions for Web Distributed</td><td class="lineno" valign="top"></td></tr>
1026      <tr><td class="lineno" valign="top"></td><td class="left">              Authoring and Versioning (WebDAV)", RFC 4918, June 2007.</td><td> </td><td class="right">              Authoring and Versioning (WebDAV)", RFC 4918, June 2007.</td><td class="lineno" valign="top"></td></tr>
1027      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1028      <tr><td class="lineno" valign="top"></td><td class="left">Appendix A.  Changes from RFC 2616</td><td> </td><td class="right">Appendix A.  Changes from RFC 2616</td><td class="lineno" valign="top"></td></tr>
1029      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1030      <tr><td><a name="diff0074" /></td></tr>
1031      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">Allow weak entity-tags in all requests except range requests</span></td><td> </td><td class="rblock">   <span class="insert">The definition of validator weakness has been expanded</span> and <span class="insert">clarified.</span></td><td class="lineno" valign="top"></td></tr>
1032      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">   (Sections 2.1</span> and <span class="delete">3.2).</span></td><td> </td><td class="rblock"><span class="insert">   (Section 2.1)</span></td><td class="lineno" valign="top"></td></tr>
1033      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1034      <tr><td><a name="diff0075" /></td></tr>
1035      <tr><td class="lineno" valign="top"></td><td class="lblock">   <span class="delete">Change "ETag"</span> header field ABNF <span class="delete">not</span> to use quoted-string, thus</td><td> </td><td class="rblock">   <span class="insert">Weak entity-tags are now allowed in all requests except range</span></td><td class="lineno" valign="top"></td></tr>
1036      <tr><td class="lineno" valign="top"></td><td class="lblock">   avoiding escaping issues.  (Section 2.3)</td><td> </td><td class="rblock"><span class="insert">   requests (Sections 2.1 and 3.2).</span></td><td class="lineno" valign="top"></td></tr>
1037      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1038      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   The ETag</span> header field ABNF <span class="insert">has been changed</span> to <span class="insert">not</span> use quoted-string,</td><td class="lineno" valign="top"></td></tr>
1039      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   thus avoiding escaping issues.  (Section 2.3)</td><td class="lineno" valign="top"></td></tr>
1040      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">                                                                         </td><td class="lineno" valign="top"></td></tr>
1041      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">   <span class="insert">ETag is defined to provide an entity tag for the selected</span></td><td class="lineno" valign="top"></td></tr>
1042      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   representation, thereby clarifying what it applies to in various</span></td><td class="lineno" valign="top"></td></tr>
1043      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   situations (such as a PUT response).  (Section 2.3)</span></td><td class="lineno" valign="top"></td></tr>
1044      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1045      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   The precedence for evaluation of conditional requests has been</span></td><td class="lineno" valign="top"></td></tr>
1046      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   defined.  (Section 5)</span></td><td class="lineno" valign="top"></td></tr>
1047      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1048      <tr><td class="lineno" valign="top"></td><td class="left">Appendix B.  Imported ABNF</td><td> </td><td class="right">Appendix B.  Imported ABNF</td><td class="lineno" valign="top"></td></tr>
1049      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1050      <tr><td class="lineno" valign="top"></td><td class="left">   The following core rules are included by reference, as defined in</td><td> </td><td class="right">   The following core rules are included by reference, as defined in</td><td class="lineno" valign="top"></td></tr>
1051      <tr><td class="lineno" valign="top"></td><td class="left">   Appendix B.1 of [RFC5234]: ALPHA (letters), CR (carriage return),</td><td> </td><td class="right">   Appendix B.1 of [RFC5234]: ALPHA (letters), CR (carriage return),</td><td class="lineno" valign="top"></td></tr>
1052      <tr><td class="lineno" valign="top"></td><td class="left">   CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double</td><td> </td><td class="right">   CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double</td><td class="lineno" valign="top"></td></tr>
1053      <tr><td class="lineno" valign="top"></td><td class="left">   quote), HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any</td><td> </td><td class="right">   quote), HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any</td><td class="lineno" valign="top"></td></tr>
1054      <tr><td class="lineno" valign="top"></td><td class="left">   8-bit sequence of data), SP (space), and VCHAR (any visible US-ASCII</td><td> </td><td class="right">   8-bit sequence of data), SP (space), and VCHAR (any visible US-ASCII</td><td class="lineno" valign="top"></td></tr>
1055      <tr><td class="lineno" valign="top"></td><td class="left">   character).</td><td> </td><td class="right">   character).</td><td class="lineno" valign="top"></td></tr>
1056      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1057      <tr><td class="lineno" valign="top"></td><td class="left">   The rules below are defined in [Part1]:</td><td> </td><td class="right">   The rules below are defined in [Part1]:</td><td class="lineno" valign="top"></td></tr>
1058      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1059      <tr><td><a name="diff0076" /></td></tr>
1060      <tr><td class="lineno" valign="top"></td><td class="lblock">     OWS           = &lt;OWS, defined in [Part1], Section <span class="delete">3.2.1&gt;</span></td><td> </td><td class="rblock">     OWS           = &lt;OWS, defined in [Part1], Section <span class="insert">3.2.3&gt;</span></td><td class="lineno" valign="top"></td></tr>
1061      <tr><td class="lineno" valign="top"></td><td class="lblock">     obs-text      = &lt;obs-text, defined in [Part1], Section <span class="delete">3.2.4&gt;</span></td><td> </td><td class="rblock">     obs-text      = &lt;obs-text, defined in [Part1], Section <span class="insert">3.2.6&gt;</span></td><td class="lineno" valign="top"></td></tr>
1062      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1063      <tr><td class="lineno" valign="top"></td><td class="left">   The rules below are defined in other parts:</td><td> </td><td class="right">   The rules below are defined in other parts:</td><td class="lineno" valign="top"></td></tr>
1064      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1065      <tr><td><a name="diff0077" /></td></tr>
1066      <tr><td class="lineno" valign="top"></td><td class="lblock">     HTTP-date     = &lt;HTTP-date, defined in [Part2], Section <span class="delete">8</span>.1.1.1&gt;</td><td> </td><td class="rblock">     HTTP-date     = &lt;HTTP-date, defined in [Part2], Section <span class="insert">7</span>.1.1.1&gt;</td><td class="lineno" valign="top"></td></tr>
1067      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1068      <tr><td class="lineno" valign="top"></td><td class="left">Appendix C.  Collected ABNF</td><td> </td><td class="right">Appendix C.  Collected ABNF</td><td class="lineno" valign="top"></td></tr>
1069      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1070      <tr><td class="lineno" valign="top"></td><td class="left">   ETag = entity-tag</td><td> </td><td class="right">   ETag = entity-tag</td><td class="lineno" valign="top"></td></tr>
1071      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1072      <tr><td><a name="diff0078" /></td></tr>
1073      <tr><td class="lineno" valign="top"></td><td class="lblock">   HTTP-date = &lt;HTTP-date, defined in [Part2], Section <span class="delete">8</span>.1.1.1&gt;</td><td> </td><td class="rblock">   HTTP-date = &lt;HTTP-date, defined in [Part2], Section <span class="insert">7</span>.1.1.1&gt;</td><td class="lineno" valign="top"></td></tr>
1074      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1075      <tr><td class="lineno" valign="top"></td><td class="left">   If-Match = "*" / ( *( "," OWS ) entity-tag *( OWS "," [ OWS</td><td> </td><td class="right">   If-Match = "*" / ( *( "," OWS ) entity-tag *( OWS "," [ OWS</td><td class="lineno" valign="top"></td></tr>
1076      <tr><td class="lineno" valign="top"></td><td class="left">    entity-tag ] ) )</td><td> </td><td class="right">    entity-tag ] ) )</td><td class="lineno" valign="top"></td></tr>
1077      <tr><td class="lineno" valign="top"></td><td class="left">   If-Modified-Since = HTTP-date</td><td> </td><td class="right">   If-Modified-Since = HTTP-date</td><td class="lineno" valign="top"></td></tr>
1078      <tr><td class="lineno" valign="top"></td><td class="left">   If-None-Match = "*" / ( *( "," OWS ) entity-tag *( OWS "," [ OWS</td><td> </td><td class="right">   If-None-Match = "*" / ( *( "," OWS ) entity-tag *( OWS "," [ OWS</td><td class="lineno" valign="top"></td></tr>
1079      <tr><td class="lineno" valign="top"></td><td class="left">    entity-tag ] ) )</td><td> </td><td class="right">    entity-tag ] ) )</td><td class="lineno" valign="top"></td></tr>
1080      <tr><td class="lineno" valign="top"></td><td class="left">   If-Unmodified-Since = HTTP-date</td><td> </td><td class="right">   If-Unmodified-Since = HTTP-date</td><td class="lineno" valign="top"></td></tr>
1081      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1082      <tr><td class="lineno" valign="top"></td><td class="left">   Last-Modified = HTTP-date</td><td> </td><td class="right">   Last-Modified = HTTP-date</td><td class="lineno" valign="top"></td></tr>
1083      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1084      <tr><td><a name="diff0079" /></td></tr>
1085      <tr><td class="lineno" valign="top"></td><td class="lblock">   OWS = &lt;OWS, defined in [Part1], Section 3.2.<span class="delete">1</span>&gt;</td><td> </td><td class="rblock">   OWS = &lt;OWS, defined in [Part1], Section 3.2.<span class="insert">3</span>&gt;</td><td class="lineno" valign="top"></td></tr>
1086      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1087      <tr><td class="lineno" valign="top"></td><td class="left">   entity-tag = [ weak ] opaque-tag</td><td> </td><td class="right">   entity-tag = [ weak ] opaque-tag</td><td class="lineno" valign="top"></td></tr>
1088      <tr><td class="lineno" valign="top"></td><td class="left">   etagc = "!" / %x23-7E ; '#'-'~'</td><td> </td><td class="right">   etagc = "!" / %x23-7E ; '#'-'~'</td><td class="lineno" valign="top"></td></tr>
1089      <tr><td class="lineno" valign="top"></td><td class="left">    / obs-text</td><td> </td><td class="right">    / obs-text</td><td class="lineno" valign="top"></td></tr>
1090      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1091      <tr><td><a name="diff0080" /></td></tr>
1092      <tr><td class="lineno" valign="top"></td><td class="lblock">   obs-text = &lt;obs-text, defined in [Part1], Section 3.2.<span class="delete">4</span>&gt;</td><td> </td><td class="rblock">   obs-text = &lt;obs-text, defined in [Part1], Section 3.2.<span class="insert">6</span>&gt;</td><td class="lineno" valign="top"></td></tr>
1093      <tr><td class="lineno" valign="top"></td><td class="left">   opaque-tag = DQUOTE *etagc DQUOTE</td><td> </td><td class="right">   opaque-tag = DQUOTE *etagc DQUOTE</td><td class="lineno" valign="top"></td></tr>
1094      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1095      <tr><td class="lineno" valign="top"></td><td class="left">   weak = %x57.2F ; W/</td><td> </td><td class="right">   weak = %x57.2F ; W/</td><td class="lineno" valign="top"></td></tr>
1096      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1097      <tr><td class="lineno" valign="top"></td><td class="left">Appendix D.  Change Log (to be removed by RFC Editor before publication)</td><td> </td><td class="right">Appendix D.  Change Log (to be removed by RFC Editor before publication)</td><td class="lineno" valign="top"></td></tr>
1098      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1099      <tr><td class="lineno" valign="top"></td><td class="left">   Changes up to the first Working Group Last Call draft are summarized</td><td> </td><td class="right">   Changes up to the first Working Group Last Call draft are summarized</td><td class="lineno" valign="top"></td></tr>
1100      <tr><td class="lineno" valign="top"></td><td class="left">   in &lt;http://tools.ietf.org/html/</td><td> </td><td class="right">   in &lt;http://tools.ietf.org/html/</td><td class="lineno" valign="top"></td></tr>
1101      <tr><td class="lineno" valign="top"></td><td class="left">   draft-ietf-httpbis-p4-conditional-19#appendix-C&gt;.</td><td> </td><td class="right">   draft-ietf-httpbis-p4-conditional-19#appendix-C&gt;.</td><td class="lineno" valign="top"></td></tr>
1102      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1103      <tr><td class="lineno"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno"></td></tr>
1104      <tr bgcolor="gray" ><td></td><th><a name="part-l14" /><small>skipping to change at</small><em> page 24, line 24</em></th><th> </th><th><a name="part-r14" /><small>skipping to change at</small><em> page 24, line 30</em></th><td></td></tr>
1105      <tr><td class="lineno" valign="top"></td><td class="left">      Since lacks definition for method != GET"</td><td> </td><td class="right">      Since lacks definition for method != GET"</td><td class="lineno" valign="top"></td></tr>
1106      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1107      <tr><td class="lineno" valign="top"></td><td class="left">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/372&gt;: "refactor</td><td> </td><td class="right">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/372&gt;: "refactor</td><td class="lineno" valign="top"></td></tr>
1108      <tr><td class="lineno" valign="top"></td><td class="left">      conditional header field descriptions"</td><td> </td><td class="right">      conditional header field descriptions"</td><td class="lineno" valign="top"></td></tr>
1109      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1110      <tr><td class="lineno" valign="top"></td><td class="left">D.2.  Since draft-ietf-httpbis-p4-conditional-20</td><td> </td><td class="right">D.2.  Since draft-ietf-httpbis-p4-conditional-20</td><td class="lineno" valign="top"></td></tr>
1111      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1112      <tr><td class="lineno" valign="top"></td><td class="left">   o  Conformance criteria and considerations regarding error handling</td><td> </td><td class="right">   o  Conformance criteria and considerations regarding error handling</td><td class="lineno" valign="top"></td></tr>
1113      <tr><td class="lineno" valign="top"></td><td class="left">      are now defined in Part 1.</td><td> </td><td class="right">      are now defined in Part 1.</td><td class="lineno" valign="top"></td></tr>
1114      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1115      <tr><td><a name="diff0081" /></td></tr>
1116      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">D.3.  Since draft-ietf-httpbis-p4-conditional-21</span></td><td class="lineno" valign="top"></td></tr>
1117      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1118      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   Closed issues:</span></td><td class="lineno" valign="top"></td></tr>
1119      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1120      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/96&gt;: "Conditional</span></td><td class="lineno" valign="top"></td></tr>
1121      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">      GET text"</span></td><td class="lineno" valign="top"></td></tr>
1122      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1123      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/350&gt;: "Optionality</span></td><td class="lineno" valign="top"></td></tr>
1124      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">      of Conditional Request Support"</span></td><td class="lineno" valign="top"></td></tr>
1125      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1126      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/384&gt;: "unclear prose</span></td><td class="lineno" valign="top"></td></tr>
1127      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">      in definition of 304"</span></td><td class="lineno" valign="top"></td></tr>
1128      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1129      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/401&gt;: "ETags and</span></td><td class="lineno" valign="top"></td></tr>
1130      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">      Conneg"</span></td><td class="lineno" valign="top"></td></tr>
1131      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1132      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/402&gt;: "Comparison</span></td><td class="lineno" valign="top"></td></tr>
1133      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">      function for If-Match and If-None-Match"</span></td><td class="lineno" valign="top"></td></tr>
1134      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1135      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/406&gt;: "304 without</span></td><td class="lineno" valign="top"></td></tr>
1136      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">      validator"</span></td><td class="lineno" valign="top"></td></tr>
1137      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert"></span></td><td class="lineno" valign="top"></td></tr>
1138      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">   o  &lt;http://tools.ietf.org/wg/httpbis/trac/ticket/427&gt;: "If-Match and</span></td><td class="lineno" valign="top"></td></tr>
1139      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock"><span class="insert">      428"</span></td><td class="lineno" valign="top"></td></tr>
1140      <tr><td class="lineno" valign="top"></td><td class="lblock"></td><td> </td><td class="rblock">                                                                         </td><td class="lineno" valign="top"></td></tr>
1141      <tr><td class="lineno" valign="top"></td><td class="left">Index</td><td> </td><td class="right">Index</td><td class="lineno" valign="top"></td></tr>
1142      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1143      <tr><td class="lineno" valign="top"></td><td class="left">   3</td><td> </td><td class="right">   3</td><td class="lineno" valign="top"></td></tr>
1144      <tr><td><a name="diff0082" /></td></tr>
1145      <tr><td class="lineno" valign="top"></td><td class="lblock">      304 Not Modified (status code)  1<span class="delete">8</span></td><td> </td><td class="rblock">      304 Not Modified (status code)  1<span class="insert">7</span></td><td class="lineno" valign="top"></td></tr>
1146      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1147      <tr><td class="lineno" valign="top"></td><td class="left">   4</td><td> </td><td class="right">   4</td><td class="lineno" valign="top"></td></tr>
1148      <tr><td><a name="diff0083" /></td></tr>
1149      <tr><td class="lineno" valign="top"></td><td class="lblock">      412 Precondition Failed (status code)  1<span class="delete">8</span></td><td> </td><td class="rblock">      412 Precondition Failed (status code)  1<span class="insert">7</span></td><td class="lineno" valign="top"></td></tr>
1150      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1151      <tr><td class="lineno" valign="top"></td><td class="left">   E</td><td> </td><td class="right">   E</td><td class="lineno" valign="top"></td></tr>
1152      <tr><td class="lineno" valign="top"></td><td class="left">      ETag header field  9</td><td> </td><td class="right">      ETag header field  9</td><td class="lineno" valign="top"></td></tr>
1153      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1154      <tr><td class="lineno" valign="top"></td><td class="left">   G</td><td> </td><td class="right">   G</td><td class="lineno" valign="top"></td></tr>
1155      <tr><td class="lineno" valign="top"></td><td class="left">      Grammar</td><td> </td><td class="right">      Grammar</td><td class="lineno" valign="top"></td></tr>
1156      <tr><td class="lineno" valign="top"></td><td class="left">         entity-tag  9</td><td> </td><td class="right">         entity-tag  9</td><td class="lineno" valign="top"></td></tr>
1157      <tr><td class="lineno" valign="top"></td><td class="left">         ETag  9</td><td> </td><td class="right">         ETag  9</td><td class="lineno" valign="top"></td></tr>
1158      <tr><td class="lineno" valign="top"></td><td class="left">         etagc  9</td><td> </td><td class="right">         etagc  9</td><td class="lineno" valign="top"></td></tr>
1159      <tr><td><a name="diff0084" /></td></tr>
1160      <tr><td class="lineno" valign="top"></td><td class="lblock">         If-Match  <span class="delete">14</span></td><td> </td><td class="rblock">         If-Match  <span class="insert">13</span></td><td class="lineno" valign="top"></td></tr>
1161      <tr><td class="lineno" valign="top"></td><td class="lblock">         If-Modified-Since  <span class="delete">16</span></td><td> </td><td class="rblock">         If-Modified-Since  15</td><td class="lineno" valign="top"></td></tr>
1162      <tr><td class="lineno" valign="top"></td><td class="lblock"><span class="delete">         If-None-Match</span>  15</td><td> </td><td class="rblock">         <span class="insert">If-None-Match  14</span></td><td class="lineno" valign="top"></td></tr>
1163      <tr><td class="lineno" valign="top"></td><td class="lblock">         If-Unmodified-Since  <span class="delete">17</span></td><td> </td><td class="rblock">         If-Unmodified-Since  <span class="insert">16</span></td><td class="lineno" valign="top"></td></tr>
1164      <tr><td class="lineno" valign="top"></td><td class="left">         Last-Modified  7</td><td> </td><td class="right">         Last-Modified  7</td><td class="lineno" valign="top"></td></tr>
1165      <tr><td class="lineno" valign="top"></td><td class="left">         opaque-tag  9</td><td> </td><td class="right">         opaque-tag  9</td><td class="lineno" valign="top"></td></tr>
1166      <tr><td class="lineno" valign="top"></td><td class="left">         weak  9</td><td> </td><td class="right">         weak  9</td><td class="lineno" valign="top"></td></tr>
1167      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1168      <tr><td class="lineno" valign="top"></td><td class="left">   I</td><td> </td><td class="right">   I</td><td class="lineno" valign="top"></td></tr>
1169      <tr><td class="lineno" valign="top"></td><td class="left">      If-Match header field  13</td><td> </td><td class="right">      If-Match header field  13</td><td class="lineno" valign="top"></td></tr>
1170      <tr><td><a name="diff0085" /></td></tr>
1171      <tr><td class="lineno" valign="top"></td><td class="lblock">      If-Modified-Since header field  1<span class="delete">6</span></td><td> </td><td class="rblock">      If-Modified-Since header field  1<span class="insert">5</span></td><td class="lineno" valign="top"></td></tr>
1172      <tr><td class="lineno" valign="top"></td><td class="left">      If-None-Match header field  14</td><td> </td><td class="right">      If-None-Match header field  14</td><td class="lineno" valign="top"></td></tr>
1173      <tr><td><a name="diff0086" /></td></tr>
1174      <tr><td class="lineno" valign="top"></td><td class="lblock">      If-Unmodified-Since header field  1<span class="delete">7</span></td><td> </td><td class="rblock">      If-Unmodified-Since header field  1<span class="insert">6</span></td><td class="lineno" valign="top"></td></tr>
1175      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1176      <tr><td class="lineno" valign="top"></td><td class="left">   L</td><td> </td><td class="right">   L</td><td class="lineno" valign="top"></td></tr>
1177      <tr><td class="lineno" valign="top"></td><td class="left">      Last-Modified header field  7</td><td> </td><td class="right">      Last-Modified header field  7</td><td class="lineno" valign="top"></td></tr>
1178      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1179      <tr><td class="lineno" valign="top"></td><td class="left">   M</td><td> </td><td class="right">   M</td><td class="lineno" valign="top"></td></tr>
1180      <tr><td class="lineno" valign="top"></td><td class="left">      metadata  5</td><td> </td><td class="right">      metadata  5</td><td class="lineno" valign="top"></td></tr>
1181      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1182      <tr><td class="lineno" valign="top"></td><td class="left">   S</td><td> </td><td class="right">   S</td><td class="lineno" valign="top"></td></tr>
1183      <tr><td class="lineno" valign="top"></td><td class="left">      selected representation  4</td><td> </td><td class="right">      selected representation  4</td><td class="lineno" valign="top"></td></tr>
1184      <tr><td class="lineno" valign="top"></td><td class="left"></td><td> </td><td class="right"></td><td class="lineno" valign="top"></td></tr>
1185
1186     <tr><td></td><td class="left"></td><td> </td><td class="right"></td><td></td></tr>
1187     <tr bgcolor="gray"><th colspan="5" align="center"><a name="end">&nbsp;End of changes. 86 change blocks.&nbsp;</a></th></tr>
1188     <tr class="stats"><td></td><th><i>255 lines changed or deleted</i></th><th><i> </i></th><th><i>308 lines changed or added</i></th><td></td></tr>
1189     <tr><td colspan="5" align="center" class="small"><br/>This html diff was produced by rfcdiff 1.38. The latest version is available from <a href="http://www.tools.ietf.org/tools/rfcdiff/" >http://tools.ietf.org/tools/rfcdiff/</a> </td></tr>
1190   </table>
1191   </body>
1192   </html>
Note: See TracBrowser for help on using the repository browser.