2004/id/draft-hallam-http-logfile-00.txt


   INTERNET DRAFT                           Phillip M. Hallam-Baker, W3C
   Expires in six months                          email: <hallam@w3.org>
                                                         Brian Behlendorf 
                                               email: <brian@organic.com>
                                                      21st February 1996
   

                          Extended Log File Format 

                      <draft-hallam-http-logfile-00.txt>

Status of this Memo

   This document is an Internet draft. Internet drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas
   and its working groups. Note that other groups may also distribute
   working information as Internet drafts. 

   Internet Drafts are draft documents valid for a maximum of six
   months and can be updated, replaced or obsoleted by other documents
   at any time. It is inappropriate to use Internet drafts as reference
   material or to cite them as other than as "work in progress". 

   To learn the current status of any Internet draft please check the
   "lid-abstracts.txt" listing contained in the Internet drafts shadow
   directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
   munnari.oz.au (Pacific Rim), ds.internic.net (US East coast) or
   ftp.isi.edu (US West coast). Further information about the IETF can
   be found at URL: http://www.cnri.reston.va.us/ 

   Distribution of this document is unlimited. Please send comments to
   the HTTP working group (HTTP-WG) of the Internet Engineering Task
   Force (IETF) at < http://www.ics.uci.edu/pub/ietf/http/. This note
   is also avaliable as a World Wide Web Consortium Working Draft
   WD-logfile-960221, archived at 
   http://www.w3.org/pub/WWW/TR/WD-logfile-960221.html   

   Extended Log File Format 

                                                             WD-logfile-960221

                          Extended Log File Format 

                    W3C Working Draft _WD-logfile-960221_

   This version:
        http://www.w3.org/pub/WWW/TR/WD-logfile-960221.html 

   Latest version:
        http://www.w3.org/pub/WWW/TR/WD-logfile.html 

   Authors:
       Phillip M. Hallam-Baker <hallam@w3.org>

Phillip M. Hallam-Baker                                                 Page 1


Extended Log File Format                                                      

       Brian Behlendorf  <brian@organic.com>

------------------------------------------------------------------------------
Status of this document

   This is a W3C Working Draft for review by W3C members and other
   interested parties. It is a draft document and may be updated,
   replaced or obsoleted by other documents at any time. It is
   inappropriate to use W3C Working Drafts as reference material or to
   cite them as other than "work in progress". A list of current W3C
   working drafts can be found at: http://www.w3.org/pub/WWW/TR 

   Note: since working drafts are subject to frequent change, you are
   advised to reference the above URL, rather than the URLs for working
   drafts themselves. 


Phillip M. Hallam-Baker                                                 Page 2


Extended Log File Format                                                      

Abstract 

   An improved format for Web server log files is presented. The format
   is extensible, permitting a wider range of data to be captured. This
   proposal is motivated by the need to capture a wider range of data
   for demographic analysis and also the needs of proxy caches. 

Introduction 

   Most Web servers offer the option to store logfiles in either the
   common log format or a proprietary format. The common log file
   format is supported by the majority of analysis tools but the
   information about each server transaction is fixed. In many cases it
   is desirable to record more information. Sites sensitive to personal
   data issues may wish to omit the recording of certain data. In
   addition ambiguities arise in analysing the common log file format
   since field separator characters may in some cases occur within
   fields. The extended log file format is designed to meet the
   following needs: 

   *   Permit control over the data recorded. 

   *   Support needs of proxies, clients and servers in a common format 

   *   Provide robust handling of character escaping issues 

   *   Allow exchange of demographic data. 

   *   Allow summary data to be expressed. 

   The log file format described permits customized logfiles to be
   recorded in a format readable by generic analysis tools. A header
   specifying the data types recorded is written out at the start of
   each log. 

   This work is in part motivated by the need to support collection of
   demographic data. This work is discussed at greater length in
   companion drafts describing  session identifier URIs [Hallam96a] and
   more consistent proxy behaviour [Hallam96b]. 

Format 

   A extended log file contains a sequence of _lines_ containing ASCII
   characters terminated by either the sequence CR or CRLF. Log file
   generators should follow the line termination convention for the
   platform on which they are executed. Analysers should accept either
   form. Each line may contain either a _directive_ or an _entry_. 

   Entries consist of a sequence of _fields_ relating to a single HTTP
   transaction. Fields are separated by whitespace, the use of tab
   characters for this purpose is encouraged. If a field is unused in a
   particular entry dash "-" marks the omitted field. Directives record
   information about the logging process itself. 

Phillip M. Hallam-Baker                                                 Page 3


Extended Log File Format                                                      

   The following directives are defined: 

   Version: _<integer>_._<integer>_ 
       The version of the extended log file format used. This draft
       defines version 1.0. 

   Fields: [_<specifier>_...] 
       Specifies the fields recorded in the log. 

   Software: _string_ 
       Identifies the software which generated the log. 

   Start-Date: _<date>_ _<time>_ 
       The date and time at which the log was started. 

   End-Date:_<date>_ _<time>_ 
       The date and time at which the log was finished. 

   Date:_<date>_ _<time>_ 
       The date and time at which the entry was added. 

   Remark: _<text>_ 
       Comment information. Data recorded in this field should be
       ignored by analysis tools. 

   The directives Version and Fields are required and should preceed
   all entries in the log. The Fields directive specifies the data
   recorded in the fields of each entry. 

Example 

   The following is an example file in the extended log format: 

   
   #Version: 1.0
   #Date: 12-Jan-1996
   #Fields: time cs-method cs-uri
   00:34:23 GET /foo/bar.html
   12:21:16 GET /foo/bar.html
   12:45:52 GET /foo/bar.html
   12:57:34 GET /foo/bar.html
   

Fields 

   The #Fields directive lists a sequence of _field identifiers_
   specifying the information recorded in each entry. Field identifiers
   may have one of the following forms: 

   _identifier_ 
       Identifier relates to the transaction as a whole. 

   _prefix_-_identifier_ 

Phillip M. Hallam-Baker                                                 Page 4


Extended Log File Format                                                      

       Identifier relates to information transfer between parties
       defined by the value _prefix_. 

   _prefix_(_header_) 
       Identifies the value of the HTTP header field _header_ for
       transfer between parties defined by the value _prefix_. Fields
       specified in this manner always have the value <string>. 

   The following prefixes are defined: 

   cs 
       Client to Server. 

   sc 
       Server to Client. 

   sr 
       Server to Remote Server, this prefix is used by proxies. 

   rs 
       Remote Server to Server, this prefix is used by proxies. 

   x 
       Application specific identifier. 

   The identifier cs-method thus refers to the method in the request
   sent by the client to the server while sc(Content-Type) refers to
   the content type field of the reply. 

Identifiers. 

   The following identifiers do not require a prefix 

   date 
       Date at which transaction completed, field has type <date> 

   time 
       Time at which transaction completed, field has type <time> 

   time-taken 
       Time taken for transaction to complete in seconds, field has
       type <fixed> 

   bytes 
       bytes transfered, field has type <integer> 

   cached 
       Records wether a cache hit occured, field has type <integer> 0
       indicates a cache miss. 

   The following identifiers require a prefix 

   ip 

Phillip M. Hallam-Baker                                                 Page 5


Extended Log File Format                                                      

       IP address and port, field has type <address> 

   dns 
       DNS name, field has type <name> 

   status 
       Status code, field has type <integer> 

   comment 
       Comment returned with status code, field has type <> 

   method 
       Method, field has type <name> 

   uri 
       URI, field has type <uri> 

   uri-stem 
       Stem protion alone of URI (omitting query), field has type <uri> 

   uri-query 
       Query portion alone of URI, field has type <uri> 

   host 
       DNS hostname used, field has type <name> 

Special fields for log summaries. 

   Analysis tools may generate log summaries. A log summary lists the
   number of operations performed on a URI but omits information
   specific to a particular transaction. 

   The following field is mandatory and must preceed all others: 

   count 
       The number of entries for which the listed data, field has type
       <> 

   The following fields may be used in place of time to allow
   aggregation of log file entries over intervals of time. 

   time-from 
       Time at which sampling began, field has type <time> 

   time-to 
       Time at which sampling ended, field has type <time> 

   interval 
       Time over which sampling occurred in seconds, field has type
       <integer> 

Entries 


Phillip M. Hallam-Baker                                                 Page 6


Extended Log File Format                                                      

   This section describes the data formats for log file field entries.
   These formats are chosen so as to avoid ambiguity, minimize the
   difficulty of generation and parsing and provide for human
   readability. 

   Each logfile entry consists of a sequence of fields separated by
   whitespace and terminated by a CR or CRLF sequence. The meanings of
   the fields are defined by a preceeding #Fields directive. If a field
   is ommitted for a particular entry a single dash "-" is substituted. 

   Log file parsers should be tolerant of errors. If an entry contains
   corrupt data or is terminated unexpectedly the parser should
   resynchronize using the end of line marker and continue to parse the
   following entries. Entries must not contain any ASCII control
   characters. 

   
   <entry> = <field>* <end-of-line>
   
   <field> = <integer> | <fixed> | <uri> | <date> | <time> | <string>
   
   <digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
   

Integer 

   
   <integer>    = <digit> +
   

   Integers are represented as a sequence of digits. 

Fixed Format Float 

   
   <float>      = <digit> [. <digit>*]
   

URI 

   A URI as specified by RFC1738, relative URIs are specified by
   RFC1808. URIs cannot by definition include whitespace or ASCII
   control characters. Consequently no ambiguity arises from their use. 

Date 

   
   <date>       = <digit> <digit> <digit> <digit>
                        "-" <digit> <digit> "-" <digit> <digit>
   

   Dates are recorded in the format YYYY-MM-DD where YYYY, MM and DD
   stand for the numeric year, month and day respectively. This format

Phillip M. Hallam-Baker                                                 Page 7


Extended Log File Format                                                      

   is chosen to assist collation using sort. 

Time 

   
   <time>       = <digit> <digit> ":" <digit> <digit>
                        [":" <digit> <digit> ["." <digit>*]
   
   
   Times are recorded in the form HH:MM, HH:MM:SS or HH:MM:SS.S where
   HH is the hour in 24 hour format, MM is minutes and SS is seconds. 

String 

   
   <string>     = '"' <schar>* '"'
   
   <schar>      = xchar | '"' '"'
   

   Strings are output in quoted form. If a string contains a quotation
   character the character is repeated. This format is unambiguous
   since fields are by definition separated by whitespace. 

   No mechanism for incorporating control characters is defined. 

Text 

   
   <text>       =  <char>* 
   

   The text field is used only by directives. 

Name 

   
   <name>       =  <alpha> [ "." <alpha> * ] 
   

   DNS name. 

Address 

   
   <name>       =  <integer> [ "." <integer> * ] [ ":" <integer> ]
   

   Numeric IP address and optional port specifier. 

Acknowledgements. 


Phillip M. Hallam-Baker                                                 Page 8


Extended Log File Format                                                      

   Robert Thau provided usefull advice and some code. John Mallery and
   Roger Hurwitz helped develop many of the ideas. 

   
   Phillip M. Hallam-Baker
   hallam@w3.org
   World Wid Web Consortium
   Cambridge MA
   
   Brian Behlendorf 
   brian@organic.com
   Organic Online
   

References. 

   
   [RFC1808] 
       R. Fielding _ Relative Uniform Resource Locators_, June 1995 

   [RFC1738] 
       T. Berners-Lee, L. Masinter, _ Uniform Resource Locators (URL)_,
       December 1994 

   [Luotonen95] 
       A. luotonen, _ The Common Logfile Format_, 1995,
       http://www.w3.org/pub/WWW/Daemon/User/Config/Logging.html 

   [Hallam96a] 
       P. M. Hallam-Baker _ Session Identification URI_ World Wide Web
       Consortium Working Draft, WD-session-id. 

   [Hallam96b] 
       P. M. Hallam-Baker _ Notification for Proxy Caches_ World Wide
       Web Consortium Working Draft, WD-proxy. 


Phillip M. Hallam-Baker                                                 Page 9

1	wakaba	1.1
2			INTERNET DRAFT Phillip M. Hallam-Baker, W3C
3			Expires in six months email: <hallam@w3.org>
4			Brian Behlendorf
5			email: <brian@organic.com>
6			21st February 1996
7
8
9			Extended Log File Format
10
11			<draft-hallam-http-logfile-00.txt>
12
13			Status of this Memo
14
15			This document is an Internet draft. Internet drafts are working
16			documents of the Internet Engineering Task Force (IETF), its areas
17			and its working groups. Note that other groups may also distribute
18			working information as Internet drafts.
19
20			Internet Drafts are draft documents valid for a maximum of six
21			months and can be updated, replaced or obsoleted by other documents
22			at any time. It is inappropriate to use Internet drafts as reference
23			material or to cite them as other than as "work in progress".
24
25			To learn the current status of any Internet draft please check the
26			"lid-abstracts.txt" listing contained in the Internet drafts shadow
27			directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
28			munnari.oz.au (Pacific Rim), ds.internic.net (US East coast) or
29			ftp.isi.edu (US West coast). Further information about the IETF can
30			be found at URL: http://www.cnri.reston.va.us/
31
32			Distribution of this document is unlimited. Please send comments to
33			the HTTP working group (HTTP-WG) of the Internet Engineering Task
34			Force (IETF) at < http://www.ics.uci.edu/pub/ietf/http/. This note
35			is also avaliable as a World Wide Web Consortium Working Draft
36			WD-logfile-960221, archived at
37			http://www.w3.org/pub/WWW/TR/WD-logfile-960221.html
38
39			Extended Log File Format
40
41			WD-logfile-960221
42
43			Extended Log File Format
44
45			W3C Working Draft _WD-logfile-960221_
46
47			This version:
48			http://www.w3.org/pub/WWW/TR/WD-logfile-960221.html
49
50			Latest version:
51			http://www.w3.org/pub/WWW/TR/WD-logfile.html
52
53			Authors:
54			Phillip M. Hallam-Baker <hallam@w3.org>
55
56			Phillip M. Hallam-Baker Page 1
57
58
59
60			Extended Log File Format
61
62			Brian Behlendorf <brian@organic.com>
63
64			------------------------------------------------------------------------------
65			Status of this document
66
67			This is a W3C Working Draft for review by W3C members and other
68			interested parties. It is a draft document and may be updated,
69			replaced or obsoleted by other documents at any time. It is
70			inappropriate to use W3C Working Drafts as reference material or to
71			cite them as other than "work in progress". A list of current W3C
72			working drafts can be found at: http://www.w3.org/pub/WWW/TR
73
74			Note: since working drafts are subject to frequent change, you are
75			advised to reference the above URL, rather than the URLs for working
76			drafts themselves.
77
78
79
80
81
82
83
84
85
86
87
88
89
90
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114
115
116			Phillip M. Hallam-Baker Page 2
117
118
119
120			Extended Log File Format
121
122			Abstract
123
124			An improved format for Web server log files is presented. The format
125			is extensible, permitting a wider range of data to be captured. This
126			proposal is motivated by the need to capture a wider range of data
127			for demographic analysis and also the needs of proxy caches.
128
129			Introduction
130
131			Most Web servers offer the option to store logfiles in either the
132			common log format or a proprietary format. The common log file
133			format is supported by the majority of analysis tools but the
134			information about each server transaction is fixed. In many cases it
135			is desirable to record more information. Sites sensitive to personal
136			data issues may wish to omit the recording of certain data. In
137			addition ambiguities arise in analysing the common log file format
138			since field separator characters may in some cases occur within
139			fields. The extended log file format is designed to meet the
140			following needs:
141
142			* Permit control over the data recorded.
143
144			* Support needs of proxies, clients and servers in a common format
145
146			* Provide robust handling of character escaping issues
147
148			* Allow exchange of demographic data.
149
150			* Allow summary data to be expressed.
151
152			The log file format described permits customized logfiles to be
153			recorded in a format readable by generic analysis tools. A header
154			specifying the data types recorded is written out at the start of
155			each log.
156
157			This work is in part motivated by the need to support collection of
158			demographic data. This work is discussed at greater length in
159			companion drafts describing session identifier URIs [Hallam96a] and
160			more consistent proxy behaviour [Hallam96b].
161
162			Format
163
164			A extended log file contains a sequence of _lines_ containing ASCII
165			characters terminated by either the sequence CR or CRLF. Log file
166			generators should follow the line termination convention for the
167			platform on which they are executed. Analysers should accept either
168			form. Each line may contain either a _directive_ or an _entry_.
169
170			Entries consist of a sequence of _fields_ relating to a single HTTP
171			transaction. Fields are separated by whitespace, the use of tab
172			characters for this purpose is encouraged. If a field is unused in a
173			particular entry dash "-" marks the omitted field. Directives record
174			information about the logging process itself.
175
176			Phillip M. Hallam-Baker Page 3
177
178
179
180			Extended Log File Format
181
182			The following directives are defined:
183
184			Version: _<integer>_._<integer>_
185			The version of the extended log file format used. This draft
186			defines version 1.0.
187
188			Fields: [_<specifier>_...]
189			Specifies the fields recorded in the log.
190
191			Software: _string_
192			Identifies the software which generated the log.
193
194			Start-Date: _<date>_ _<time>_
195			The date and time at which the log was started.
196
197			End-Date:_<date>_ _<time>_
198			The date and time at which the log was finished.
199
200			Date:_<date>_ _<time>_
201			The date and time at which the entry was added.
202
203			Remark: _<text>_
204			Comment information. Data recorded in this field should be
205			ignored by analysis tools.
206
207			The directives Version and Fields are required and should preceed
208			all entries in the log. The Fields directive specifies the data
209			recorded in the fields of each entry.
210
211			Example
212
213			The following is an example file in the extended log format:
214
215
216			#Version: 1.0
217			#Date: 12-Jan-1996
218			#Fields: time cs-method cs-uri
219			00:34:23 GET /foo/bar.html
220			12:21:16 GET /foo/bar.html
221			12:45:52 GET /foo/bar.html
222			12:57:34 GET /foo/bar.html
223
224
225			Fields
226
227			The #Fields directive lists a sequence of _field identifiers_
228			specifying the information recorded in each entry. Field identifiers
229			may have one of the following forms:
230
231			_identifier_
232			Identifier relates to the transaction as a whole.
233
234			_prefix_-_identifier_
235
236			Phillip M. Hallam-Baker Page 4
237
238
239
240			Extended Log File Format
241
242			Identifier relates to information transfer between parties
243			defined by the value _prefix_.
244
245			_prefix_(_header_)
246			Identifies the value of the HTTP header field _header_ for
247			transfer between parties defined by the value _prefix_. Fields
248			specified in this manner always have the value <string>.
249
250			The following prefixes are defined:
251
252			cs
253			Client to Server.
254
255			sc
256			Server to Client.
257
258			sr
259			Server to Remote Server, this prefix is used by proxies.
260
261			rs
262			Remote Server to Server, this prefix is used by proxies.
263
264			x
265			Application specific identifier.
266
267			The identifier cs-method thus refers to the method in the request
268			sent by the client to the server while sc(Content-Type) refers to
269			the content type field of the reply.
270
271			Identifiers.
272
273			The following identifiers do not require a prefix
274
275			date
276			Date at which transaction completed, field has type <date>
277
278			time
279			Time at which transaction completed, field has type <time>
280
281			time-taken
282			Time taken for transaction to complete in seconds, field has
283			type <fixed>
284
285			bytes
286			bytes transfered, field has type <integer>
287
288			cached
289			Records wether a cache hit occured, field has type <integer> 0
290			indicates a cache miss.
291
292			The following identifiers require a prefix
293
294			ip
295
296			Phillip M. Hallam-Baker Page 5
297
298
299
300			Extended Log File Format
301
302			IP address and port, field has type <address>
303
304			dns
305			DNS name, field has type <name>
306
307			status
308			Status code, field has type <integer>
309
310			comment
311			Comment returned with status code, field has type <>
312
313			method
314			Method, field has type <name>
315
316			uri
317			URI, field has type <uri>
318
319			uri-stem
320			Stem protion alone of URI (omitting query), field has type <uri>
321
322			uri-query
323			Query portion alone of URI, field has type <uri>
324
325			host
326			DNS hostname used, field has type <name>
327
328			Special fields for log summaries.
329
330			Analysis tools may generate log summaries. A log summary lists the
331			number of operations performed on a URI but omits information
332			specific to a particular transaction.
333
334			The following field is mandatory and must preceed all others:
335
336			count
337			The number of entries for which the listed data, field has type
338			<>
339
340			The following fields may be used in place of time to allow
341			aggregation of log file entries over intervals of time.
342
343			time-from
344			Time at which sampling began, field has type <time>
345
346			time-to
347			Time at which sampling ended, field has type <time>
348
349			interval
350			Time over which sampling occurred in seconds, field has type
351			<integer>
352
353			Entries
354
355
356			Phillip M. Hallam-Baker Page 6
357
358
359
360			Extended Log File Format
361
362			This section describes the data formats for log file field entries.
363			These formats are chosen so as to avoid ambiguity, minimize the
364			difficulty of generation and parsing and provide for human
365			readability.
366
367			Each logfile entry consists of a sequence of fields separated by
368			whitespace and terminated by a CR or CRLF sequence. The meanings of
369			the fields are defined by a preceeding #Fields directive. If a field
370			is ommitted for a particular entry a single dash "-" is substituted.
371
372			Log file parsers should be tolerant of errors. If an entry contains
373			corrupt data or is terminated unexpectedly the parser should
374			resynchronize using the end of line marker and continue to parse the
375			following entries. Entries must not contain any ASCII control
376			characters.
377
378
379			<entry> = <field>* <end-of-line>
380
381			<field> = <integer> \| <fixed> \| <uri> \| <date> \| <time> \| <string>
382
383			<digit = "0" \| "1" \| "2" \| "3" \| "4" \| "5" \| "6" \| "7" \| "8" \| "9"
384
385
386			Integer
387
388
389			<integer> = <digit> +
390
391
392			Integers are represented as a sequence of digits.
393
394			Fixed Format Float
395
396
397			<float> = <digit> [. <digit>*]
398
399
400			URI
401
402			A URI as specified by RFC1738, relative URIs are specified by
403			RFC1808. URIs cannot by definition include whitespace or ASCII
404			control characters. Consequently no ambiguity arises from their use.
405
406			Date
407
408
409			<date> = <digit> <digit> <digit> <digit>
410			"-" <digit> <digit> "-" <digit> <digit>
411
412
413			Dates are recorded in the format YYYY-MM-DD where YYYY, MM and DD
414			stand for the numeric year, month and day respectively. This format
415
416			Phillip M. Hallam-Baker Page 7
417
418
419
420			Extended Log File Format
421
422			is chosen to assist collation using sort.
423
424			Time
425
426
427			<time> = <digit> <digit> ":" <digit> <digit>
428			[":" <digit> <digit> ["." <digit>*]
429
430
431
432			Times are recorded in the form HH:MM, HH:MM:SS or HH:MM:SS.S where
433			HH is the hour in 24 hour format, MM is minutes and SS is seconds.
434
435			String
436
437
438			<string> = '"' <schar>* '"'
439
440			<schar> = xchar \| '"' '"'
441
442
443			Strings are output in quoted form. If a string contains a quotation
444			character the character is repeated. This format is unambiguous
445			since fields are by definition separated by whitespace.
446
447			No mechanism for incorporating control characters is defined.
448
449			Text
450
451
452			<text> = <char>*
453
454
455			The text field is used only by directives.
456
457			Name
458
459
460			<name> = <alpha> [ "." <alpha> * ]
461
462
463			DNS name.
464
465			Address
466
467
468			<name> = <integer> [ "." <integer> * ] [ ":" <integer> ]
469
470
471			Numeric IP address and optional port specifier.
472
473			Acknowledgements.
474
475
476			Phillip M. Hallam-Baker Page 8
477
478
479
480			Extended Log File Format
481
482			Robert Thau provided usefull advice and some code. John Mallery and
483			Roger Hurwitz helped develop many of the ideas.
484
485
486			Phillip M. Hallam-Baker
487			hallam@w3.org
488			World Wid Web Consortium
489			Cambridge MA
490
491			Brian Behlendorf
492			brian@organic.com
493			Organic Online
494
495
496			References.
497
498
499			[RFC1808]
500			R. Fielding _ Relative Uniform Resource Locators_, June 1995
501
502			[RFC1738]
503			T. Berners-Lee, L. Masinter, _ Uniform Resource Locators (URL)_,
504			December 1994
505
506			[Luotonen95]
507			A. luotonen, _ The Common Logfile Format_, 1995,
508			http://www.w3.org/pub/WWW/Daemon/User/Config/Logging.html
509
510			[Hallam96a]
511			P. M. Hallam-Baker _ Session Identification URI_ World Wide Web
512			Consortium Working Draft, WD-session-id.
513
514			[Hallam96b]
515			P. M. Hallam-Baker _ Notification for Proxy Caches_ World Wide
516			Web Consortium Working Draft, WD-proxy.
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536			Phillip M. Hallam-Baker Page 9
537