draft-ietf-httpbis-p6-cache-18.txt		draft-ietf-httpbis-p6-cache-latest.txt
	HTTPbis Working Group R. Fielding, Ed.		HTTPbis Working Group R. Fielding, Ed.
	Internet-Draft Adobe		Internet-Draft Adobe
	Obsoletes: 2616 (if approved) J. Gettys		Obsoletes: 2616 (if approved) J. Gettys
	Intended status: Standards Track Alcatel-Lucent		Intended status: Standards Track Alcatel-Lucent
	Expires: July 7, 2012 J. Mogul		Expires: August 6, 2012 J. Mogul
	HP		HP
	H. Frystyk		H. Frystyk
	Microsoft		Microsoft
	L. Masinter		L. Masinter
	Adobe		Adobe
	P. Leach		P. Leach
	Microsoft		Microsoft
	T. Berners-Lee		T. Berners-Lee
	W3C/MIT		W3C/MIT
	Y. Lafon, Ed.		Y. Lafon, Ed.
	W3C		W3C
	M. Nottingham, Ed.		M. Nottingham, Ed.
	Rackspace		Rackspace
	J. Reschke, Ed.		J. Reschke, Ed.
	greenbytes		greenbytes
	January 4, 2012		February 3, 2012
	HTTP/1.1, part 6: Caching		HTTP/1.1, part 6: Caching
	draft-ietf-httpbis-p6-cache-18		draft-ietf-httpbis-p6-cache-latest
	Abstract		Abstract
	The Hypertext Transfer Protocol (HTTP) is an application-level		The Hypertext Transfer Protocol (HTTP) is an application-level
	protocol for distributed, collaborative, hypertext information		protocol for distributed, collaborative, hypertext information
	systems. HTTP has been in use by the World Wide Web global		systems. HTTP has been in use by the World Wide Web global
	information initiative since 1990. This document is Part 6 of the		information initiative since 1990. This document is Part 6 of the
	seven-part specification that defines the protocol referred to as		seven-part specification that defines the protocol referred to as
	"HTTP/1.1" and, taken together, obsoletes RFC 2616.		"HTTP/1.1" and, taken together, obsoletes RFC 2616.
	skipping to change at page 2, line 6		skipping to change at page 2, line 6
	Discussion of this draft should take place on the HTTPBIS working		Discussion of this draft should take place on the HTTPBIS working
	group mailing list (ietf-http-wg@w3.org), which is archived at		group mailing list (ietf-http-wg@w3.org), which is archived at
	<http://lists.w3.org/Archives/Public/ietf-http-wg/>.		<http://lists.w3.org/Archives/Public/ietf-http-wg/>.
	The current issues list is at		The current issues list is at
	<http://tools.ietf.org/wg/httpbis/trac/report/3> and related		<http://tools.ietf.org/wg/httpbis/trac/report/3> and related
	documents (including fancy diffs) can be found at		documents (including fancy diffs) can be found at
	<http://tools.ietf.org/wg/httpbis/>.		<http://tools.ietf.org/wg/httpbis/>.
	The changes in this draft are summarized in Appendix C.19.		The changes in this draft are summarized in Appendix C.20.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on July 7, 2012.		This Internet-Draft will expire on August 6, 2012.
	Copyright Notice		Copyright Notice
	Copyright (c) 2012 IETF Trust and the persons identified as the		Copyright (c) 2012 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 3, line 47		skipping to change at page 3, line 47
	3.5. Vary . . . . . . . . . . . . . . . . . . . . . . . . . . . 28		3.5. Vary . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
	3.6. Warning . . . . . . . . . . . . . . . . . . . . . . . . . 29		3.6. Warning . . . . . . . . . . . . . . . . . . . . . . . . . 29
	3.6.1. 110 Response is Stale . . . . . . . . . . . . . . . . 31		3.6.1. 110 Response is Stale . . . . . . . . . . . . . . . . 31
	3.6.2. 111 Revalidation Failed . . . . . . . . . . . . . . . 31		3.6.2. 111 Revalidation Failed . . . . . . . . . . . . . . . 31
	3.6.3. 112 Disconnected Operation . . . . . . . . . . . . . . 31		3.6.3. 112 Disconnected Operation . . . . . . . . . . . . . . 31
	3.6.4. 113 Heuristic Expiration . . . . . . . . . . . . . . . 31		3.6.4. 113 Heuristic Expiration . . . . . . . . . . . . . . . 31
	3.6.5. 199 Miscellaneous Warning . . . . . . . . . . . . . . 31		3.6.5. 199 Miscellaneous Warning . . . . . . . . . . . . . . 31
	3.6.6. 214 Transformation Applied . . . . . . . . . . . . . . 31		3.6.6. 214 Transformation Applied . . . . . . . . . . . . . . 31
	3.6.7. 299 Miscellaneous Persistent Warning . . . . . . . . . 31		3.6.7. 299 Miscellaneous Persistent Warning . . . . . . . . . 31
	3.6.8. Warn Code Extensions . . . . . . . . . . . . . . . . . 32		3.6.8. Warn Code Extensions . . . . . . . . . . . . . . . . . 32
	3.7. History Lists . . . . . . . . . . . . . . . . . . . . . . 32		4. History Lists . . . . . . . . . . . . . . . . . . . . . . . . 32
	3.8. IANA Considerations . . . . . . . . . . . . . . . . . . . 32		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
	3.8.1. Cache Directive Registry . . . . . . . . . . . . . . . 32		5.1. Cache Directive Registry . . . . . . . . . . . . . . . . . 32
	3.8.2. Warn Code Registry . . . . . . . . . . . . . . . . . . 33		5.2. Warn Code Registry . . . . . . . . . . . . . . . . . . . . 33
	3.9. Header Field Registration . . . . . . . . . . . . . . . . 33		5.3. Header Field Registration . . . . . . . . . . . . . . . . 33
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 34		6. Security Considerations . . . . . . . . . . . . . . . . . . . 34
	5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 34		7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 34
	6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 34		8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 34
	6.1. Normative References . . . . . . . . . . . . . . . . . . . 34		8.1. Normative References . . . . . . . . . . . . . . . . . . . 34
	6.2. Informative References . . . . . . . . . . . . . . . . . . 35		8.2. Informative References . . . . . . . . . . . . . . . . . . 35
	Appendix A. Changes from RFC 2616 . . . . . . . . . . . . . . . . 35		Appendix A. Changes from RFC 2616 . . . . . . . . . . . . . . . . 35
	Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 36		Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 36
	Appendix C. Change Log (to be removed by RFC Editor before		Appendix C. Change Log (to be removed by RFC Editor before
	publication) . . . . . . . . . . . . . . . . . . . . 37		publication) . . . . . . . . . . . . . . . . . . . . 37
	C.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 37		C.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 37
	C.2. Since draft-ietf-httpbis-p6-cache-00 . . . . . . . . . . . 37		C.2. Since draft-ietf-httpbis-p6-cache-00 . . . . . . . . . . . 37
	C.3. Since draft-ietf-httpbis-p6-cache-01 . . . . . . . . . . . 38		C.3. Since draft-ietf-httpbis-p6-cache-01 . . . . . . . . . . . 38
	C.4. Since draft-ietf-httpbis-p6-cache-02 . . . . . . . . . . . 38		C.4. Since draft-ietf-httpbis-p6-cache-02 . . . . . . . . . . . 38
	C.5. Since draft-ietf-httpbis-p6-cache-03 . . . . . . . . . . . 39		C.5. Since draft-ietf-httpbis-p6-cache-03 . . . . . . . . . . . 39
	C.6. Since draft-ietf-httpbis-p6-cache-04 . . . . . . . . . . . 39		C.6. Since draft-ietf-httpbis-p6-cache-04 . . . . . . . . . . . 39
	skipping to change at page 4, line 31		skipping to change at page 4, line 31
	C.10. Since draft-ietf-httpbis-p6-cache-08 . . . . . . . . . . . 40		C.10. Since draft-ietf-httpbis-p6-cache-08 . . . . . . . . . . . 40
	C.11. Since draft-ietf-httpbis-p6-cache-09 . . . . . . . . . . . 41		C.11. Since draft-ietf-httpbis-p6-cache-09 . . . . . . . . . . . 41
	C.12. Since draft-ietf-httpbis-p6-cache-10 . . . . . . . . . . . 41		C.12. Since draft-ietf-httpbis-p6-cache-10 . . . . . . . . . . . 41
	C.13. Since draft-ietf-httpbis-p6-cache-11 . . . . . . . . . . . 41		C.13. Since draft-ietf-httpbis-p6-cache-11 . . . . . . . . . . . 41
	C.14. Since draft-ietf-httpbis-p6-cache-12 . . . . . . . . . . . 42		C.14. Since draft-ietf-httpbis-p6-cache-12 . . . . . . . . . . . 42
	C.15. Since draft-ietf-httpbis-p6-cache-13 . . . . . . . . . . . 42		C.15. Since draft-ietf-httpbis-p6-cache-13 . . . . . . . . . . . 42
	C.16. Since draft-ietf-httpbis-p6-cache-14 . . . . . . . . . . . 42		C.16. Since draft-ietf-httpbis-p6-cache-14 . . . . . . . . . . . 42
	C.17. Since draft-ietf-httpbis-p6-cache-15 . . . . . . . . . . . 42		C.17. Since draft-ietf-httpbis-p6-cache-15 . . . . . . . . . . . 42
	C.18. Since draft-ietf-httpbis-p6-cache-16 . . . . . . . . . . . 43		C.18. Since draft-ietf-httpbis-p6-cache-16 . . . . . . . . . . . 43
	C.19. Since draft-ietf-httpbis-p6-cache-17 . . . . . . . . . . . 43		C.19. Since draft-ietf-httpbis-p6-cache-17 . . . . . . . . . . . 43
			C.20. Since draft-ietf-httpbis-p6-cache-18 . . . . . . . . . . . 43
	Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43		Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
	1. Introduction		1. Introduction
	HTTP is typically used for distributed information systems, where		HTTP is typically used for distributed information systems, where
	performance can be improved by the use of response caches. This		performance can be improved by the use of response caches. This
	document defines aspects of HTTP/1.1 related to caching and reusing		document defines aspects of HTTP/1.1 related to caching and reusing
	response messages.		response messages.
	1.1. Purpose		1.1. Purpose
	skipping to change at page 7, line 45		skipping to change at page 7, line 45
	define specific error handling mechanisms, except in cases where it		define specific error handling mechanisms, except in cases where it
	has direct impact on security. This is because different uses of the		has direct impact on security. This is because different uses of the
	protocol require different error handling strategies; for example, a		protocol require different error handling strategies; for example, a
	Web browser may wish to transparently recover from a response where		Web browser may wish to transparently recover from a response where
	the Location header field doesn't parse according to the ABNF,		the Location header field doesn't parse according to the ABNF,
	whereby in a systems control protocol using HTTP, this type of error		whereby in a systems control protocol using HTTP, this type of error
	recovery could lead to dangerous consequences.		recovery could lead to dangerous consequences.
	1.4. Syntax Notation		1.4. Syntax Notation
	This specification uses the ABNF syntax defined in Section 1.2 of		This specification uses the Augmented Backus-Naur Form (ABNF)
	[Part1] (which extends the syntax defined in [RFC5234] with a list		notation of [RFC5234] with the list rule extension defined in Section
	rule). Appendix B shows the collected ABNF, with the list rule		1.2 of [Part1]. Appendix B shows the collected ABNF with the list
	expanded.		rule expanded.
	The following core rules are included by reference, as defined in		The following core rules are included by reference, as defined in
	[RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF		[RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF
	(CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),		(CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),
	HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit		HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit
	sequence of data), SP (space), and VCHAR (any visible US-ASCII		sequence of data), SP (space), and VCHAR (any visible US-ASCII
	character).		character).
	1.4.1. Core Rules		1.4.1. Core Rules
	The core rules below are defined in [Part1]:		The core rules below are defined in [Part1]:
	OWS = <OWS, defined in [Part1], Section 1.2.2>		OWS = <OWS, defined in [Part1], Section 3.2.1>
	quoted-string = <quoted-string, defined in [Part1], Section 3.2.3>		quoted-string = <quoted-string, defined in [Part1], Section 3.2.4>
	token = <token, defined in [Part1], Section 3.2.3>		token = <token, defined in [Part1], Section 3.2.4>
	1.4.2. ABNF Rules defined in other Parts of the Specification		1.4.2. ABNF Rules defined in other Parts of the Specification
	The ABNF rules below are defined in other parts:		The ABNF rules below are defined in other parts:
	field-name = <field-name, defined in [Part1], Section 3.2>		field-name = <field-name, defined in [Part1], Section 3.2>
	HTTP-date = <HTTP-date, defined in [Part2], Section 8>		HTTP-date = <HTTP-date, defined in [Part2], Section 8>
	port = <port, defined in [Part1], Section 2.7>		port = <port, defined in [Part1], Section 2.7>
	pseudonym = <pseudonym, defined in [Part1], Section 8.8>		pseudonym = <pseudonym, defined in [Part1], Section 8.8>
	uri-host = <uri-host, defined in [Part1], Section 2.7>		uri-host = <uri-host, defined in [Part1], Section 2.7>
	skipping to change at page 9, line 35		skipping to change at page 9, line 35
	A cache MUST NOT store a response to any request, unless:		A cache MUST NOT store a response to any request, unless:
	o The request method is understood by the cache and defined as being		o The request method is understood by the cache and defined as being
	cacheable, and		cacheable, and
	o the response status code is understood by the cache, and		o the response status code is understood by the cache, and
	o the "no-store" cache directive (see Section 3.2) does not appear		o the "no-store" cache directive (see Section 3.2) does not appear
	in request or response header fields, and		in request or response header fields, and
	o the "private" cache response directive (see Section 3.2.2 does not		o the "private" cache response directive (see Section 3.2.2) does
	appear in the response, if the cache is shared, and		not appear in the response, if the cache is shared, and
	o the "Authorization" header field (see Section 4.1 of [Part7]) does		o the "Authorization" header field (see Section 4.1 of [Part7]) does
	not appear in the request, if the cache is shared, unless the		not appear in the request, if the cache is shared, unless the
	response explicitly allows it (see Section 2.6), and		response explicitly allows it (see Section 2.6), and
	o the response either:		o the response either:
	* contains an Expires header field (see Section 3.3), or		* contains an Expires header field (see Section 3.3), or
	* contains a max-age response cache directive (see		* contains a max-age response cache directive (see
	skipping to change at page 12, line 46		skipping to change at page 12, line 46
	The freshness_lifetime is defined in Section 2.3.1; the current_age		The freshness_lifetime is defined in Section 2.3.1; the current_age
	is defined in Section 2.3.2.		is defined in Section 2.3.2.
	Additionally, clients can influence freshness calculation -- either		Additionally, clients can influence freshness calculation -- either
	constraining it relaxing it -- by using the max-age and min-fresh		constraining it relaxing it -- by using the max-age and min-fresh
	request cache directives. See Section 3.2.1 for details.		request cache directives. See Section 3.2.1 for details.
	Note that freshness applies only to cache operation; it cannot be		Note that freshness applies only to cache operation; it cannot be
	used to force a user agent to refresh its display or reload a		used to force a user agent to refresh its display or reload a
	resource. See Section 3.7 for an explanation of the difference		resource. See Section 4 for an explanation of the difference between
	between caches and history mechanisms.		caches and history mechanisms.
	2.3.1. Calculating Freshness Lifetime		2.3.1. Calculating Freshness Lifetime
	A cache can calculate the freshness lifetime (denoted as		A cache can calculate the freshness lifetime (denoted as
	freshness_lifetime) of a response by using the first match of:		freshness_lifetime) of a response by using the first match of:
	o If the cache is shared and the s-maxage response cache directive		o If the cache is shared and the s-maxage response cache directive
	(Section 3.2.2) is present, use its value, or		(Section 3.2.2) is present, use its value, or
	o If the max-age response cache directive (Section 3.2.2) is		o If the max-age response cache directive (Section 3.2.2) is
	skipping to change at page 32, line 23		skipping to change at page 32, line 23
	o Short Description		o Short Description
	o Pointer to specification text		o Pointer to specification text
	Values to be added to this name space are subject to IETF review		Values to be added to this name space are subject to IETF review
	([RFC5226], Section 4.1).		([RFC5226], Section 4.1).
	The registry itself is maintained at		The registry itself is maintained at
	<http://www.iana.org/assignments/http-warn-codes>.		<http://www.iana.org/assignments/http-warn-codes>.
	3.7. History Lists		4. History Lists
	User agents often have history mechanisms, such as "Back" buttons and		User agents often have history mechanisms, such as "Back" buttons and
	history lists, that can be used to redisplay a representation		history lists, that can be used to redisplay a representation
	retrieved earlier in a session.		retrieved earlier in a session.
	The freshness model (Section 2.3) does not necessarily apply to		The freshness model (Section 2.3) does not necessarily apply to
	history mechanisms. I.e., a history mechanism can display a previous		history mechanisms. I.e., a history mechanism can display a previous
	representation even if it has expired.		representation even if it has expired.
	This does not prohibit the history mechanism from telling the user		This does not prohibit the history mechanism from telling the user
	that a view might be stale, or from honoring cache directives (e.g.,		that a view might be stale, or from honoring cache directives (e.g.,
	Cache-Control: no-store).		Cache-Control: no-store).
	3.8. IANA Considerations		5. IANA Considerations
	3.8.1. Cache Directive Registry		5.1. Cache Directive Registry
	The registration procedure for HTTP Cache Directives is defined by		The registration procedure for HTTP Cache Directives is defined by
	Section 3.2.3 of this document.		Section 3.2.3 of this document.
	The HTTP Cache Directive Registry shall be created at		The HTTP Cache Directive Registry shall be created at
	<http://www.iana.org/assignments/http-cache-directives> and be		<http://www.iana.org/assignments/http-cache-directives> and be
	populated with the registrations below:		populated with the registrations below:
	+------------------------+------------------------------+		+------------------------+------------------------------+
	| Cache Directive | Reference |		| Cache Directive | Reference |
	skipping to change at page 33, line 24		skipping to change at page 33, line 24
	| no-transform | Section 3.2.1, Section 3.2.2 |		| no-transform | Section 3.2.1, Section 3.2.2 |
	| only-if-cached | Section 3.2.1 |		| only-if-cached | Section 3.2.1 |
	| private | Section 3.2.2 |		| private | Section 3.2.2 |
	| proxy-revalidate | Section 3.2.2 |		| proxy-revalidate | Section 3.2.2 |
	| public | Section 3.2.2 |		| public | Section 3.2.2 |
	| s-maxage | Section 3.2.2 |		| s-maxage | Section 3.2.2 |
	| stale-if-error | [RFC5861], Section 4 |		| stale-if-error | [RFC5861], Section 4 |
	| stale-while-revalidate | [RFC5861], Section 3 |		| stale-while-revalidate | [RFC5861], Section 3 |
	+------------------------+------------------------------+		+------------------------+------------------------------+
	3.8.2. Warn Code Registry		5.2. Warn Code Registry
	The registration procedure for HTTP Warn Codes is defined by		The registration procedure for HTTP Warn Codes is defined by
	Section 3.6.8 of this document.		Section 3.6.8 of this document.
	The HTTP Warn Code Registry shall be created at		The HTTP Warn Code Registry shall be created at
	<http://www.iana.org/assignments/http-cache-directives> and be		<http://www.iana.org/assignments/http-cache-directives> and be
	populated with the registrations below:		populated with the registrations below:
	+-----------+----------------------------------+---------------+		+-----------+----------------------------------+---------------+
	| Warn Code | Short Description | Reference |		| Warn Code | Short Description | Reference |
	+-----------+----------------------------------+---------------+		+-----------+----------------------------------+---------------+
	| 110 | Response is Stale | Section 3.6.1 |		| 110 | Response is Stale | Section 3.6.1 |
	| 111 | Revalidation Failed | Section 3.6.2 |		| 111 | Revalidation Failed | Section 3.6.2 |
	| 112 | Disconnected Operation | Section 3.6.3 |		| 112 | Disconnected Operation | Section 3.6.3 |
	| 113 | Heuristic Expiration | Section 3.6.4 |		| 113 | Heuristic Expiration | Section 3.6.4 |
	| 199 | Miscellaneous Warning | Section 3.6.5 |		| 199 | Miscellaneous Warning | Section 3.6.5 |
	| 214 | Transformation Applied | Section 3.6.6 |		| 214 | Transformation Applied | Section 3.6.6 |
	| 299 | Miscellaneous Persistent Warning | Section 3.6.7 |		| 299 | Miscellaneous Persistent Warning | Section 3.6.7 |
	+-----------+----------------------------------+---------------+		+-----------+----------------------------------+---------------+
	3.9. Header Field Registration		5.3. Header Field Registration
	The Message Header Field Registry located at <http://www.iana.org/		The Message Header Field Registry located at <http://www.iana.org/
	assignments/message-headers/message-header-index.html> shall be		assignments/message-headers/message-header-index.html> shall be
	updated with the permanent registrations below (see [RFC3864]):		updated with the permanent registrations below (see [RFC3864]):
	+-------------------+----------+----------+-------------+		+-------------------+----------+----------+-------------+
	| Header Field Name | Protocol | Status | Reference |		| Header Field Name | Protocol | Status | Reference |
	+-------------------+----------+----------+-------------+		+-------------------+----------+----------+-------------+
	| Age | http | standard | Section 3.1 |		| Age | http | standard | Section 3.1 |
	| Cache-Control | http | standard | Section 3.2 |		| Cache-Control | http | standard | Section 3.2 |
	| Expires | http | standard | Section 3.3 |		| Expires | http | standard | Section 3.3 |
	| Pragma | http | standard | Section 3.4 |		| Pragma | http | standard | Section 3.4 |
	| Vary | http | standard | Section 3.5 |		| Vary | http | standard | Section 3.5 |
	| Warning | http | standard | Section 3.6 |		| Warning | http | standard | Section 3.6 |
	+-------------------+----------+----------+-------------+		+-------------------+----------+----------+-------------+
	The change controller is: "IETF (iesg@ietf.org) - Internet		The change controller is: "IETF (iesg@ietf.org) - Internet
	Engineering Task Force".		Engineering Task Force".
	4. Security Considerations		6. Security Considerations
	Caches expose additional potential vulnerabilities, since the		Caches expose additional potential vulnerabilities, since the
	contents of the cache represent an attractive target for malicious		contents of the cache represent an attractive target for malicious
	exploitation. Because cache contents persist after an HTTP request		exploitation. Because cache contents persist after an HTTP request
	is complete, an attack on the cache can reveal information long after		is complete, an attack on the cache can reveal information long after
	a user believes that the information has been removed from the		a user believes that the information has been removed from the
	network. Therefore, cache contents need to be protected as sensitive		network. Therefore, cache contents need to be protected as sensitive
	information.		information.
	5. Acknowledgments		7. Acknowledgments
	See Section 11 of [Part1].		See Section 11 of [Part1].
	6. References		8. References
	6.1. Normative References		8.1. Normative References
	[Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections,		and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections,
	and Message Parsing", draft-ietf-httpbis-p1-messaging-18		and Message Parsing",
	(work in progress), January 2012.		draft-ietf-httpbis-p1-messaging-latest (work in progress),
			February 2012.
	[Part2] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part2] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 2: Message		and J. Reschke, Ed., "HTTP/1.1, part 2: Message
	Semantics", draft-ietf-httpbis-p2-semantics-18 (work in		Semantics", draft-ietf-httpbis-p2-semantics-latest (work
	progress), January 2012.		in progress), February 2012.
	[Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional		and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional
	Requests", draft-ietf-httpbis-p4-conditional-18 (work in		Requests", draft-ietf-httpbis-p4-conditional-latest (work
	progress), January 2012.		in progress), February 2012.
	[Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and		and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and
	Partial Responses", draft-ietf-httpbis-p5-range-18 (work		Partial Responses", draft-ietf-httpbis-p5-range-latest
	in progress), January 2012.		(work in progress), February 2012.
	[Part7] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part7] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 7: Authentication",		and J. Reschke, Ed., "HTTP/1.1, part 7: Authentication",
	draft-ietf-httpbis-p7-auth-18 (work in progress),		draft-ietf-httpbis-p7-auth-latest (work in progress),
	January 2012.		February 2012.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234, January 2008.		Specifications: ABNF", STD 68, RFC 5234, January 2008.
	6.2. Informative References		8.2. Informative References
	[RFC1305] Mills, D., "Network Time Protocol (Version 3)		[RFC1305] Mills, D., "Network Time Protocol (Version 3)
	Specification, Implementation", RFC 1305, March 1992.		Specification, Implementation", RFC 1305, March 1992.
	[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,		[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext		Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
	Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.		Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
	[RFC3864] Klyne, G., Nottingham, M., and J. Mogul, "Registration		[RFC3864] Klyne, G., Nottingham, M., and J. Mogul, "Registration
	Procedures for Message Header Fields", BCP 90, RFC 3864,		Procedures for Message Header Fields", BCP 90, RFC 3864,
	skipping to change at page 36, line 25		skipping to change at page 36, line 28
	Age = delta-seconds		Age = delta-seconds
	Cache-Control = *( "," OWS ) cache-directive *( OWS "," [ OWS		Cache-Control = *( "," OWS ) cache-directive *( OWS "," [ OWS
	cache-directive ] )		cache-directive ] )
	Expires = HTTP-date		Expires = HTTP-date
	HTTP-date = <HTTP-date, defined in [Part2], Section 8>		HTTP-date = <HTTP-date, defined in [Part2], Section 8>
	OWS = <OWS, defined in [Part1], Section 1.2.2>		OWS = <OWS, defined in [Part1], Section 3.2.1>
	Pragma = *( "," OWS ) pragma-directive *( OWS "," [ OWS		Pragma = *( "," OWS ) pragma-directive *( OWS "," [ OWS
	pragma-directive ] )		pragma-directive ] )
	Vary = "*" / ( *( "," OWS ) field-name *( OWS "," [ OWS field-name ]		Vary = "*" / ( *( "," OWS ) field-name *( OWS "," [ OWS field-name ]
	) )		) )
	Warning = *( "," OWS ) warning-value *( OWS "," [ OWS warning-value ]		Warning = *( "," OWS ) warning-value *( OWS "," [ OWS warning-value ]
	)		)
	skipping to change at page 36, line 50		skipping to change at page 37, line 4
	"min-fresh=" delta-seconds ) / "no-transform" / "only-if-cached" /		"min-fresh=" delta-seconds ) / "no-transform" / "only-if-cached" /
	cache-extension		cache-extension
	cache-response-directive = "public" / ( "private" [ "=" DQUOTE *( ","		cache-response-directive = "public" / ( "private" [ "=" DQUOTE *( ","
	OWS ) field-name *( OWS "," [ OWS field-name ] ) DQUOTE ] ) / (		OWS ) field-name *( OWS "," [ OWS field-name ] ) DQUOTE ] ) / (
	"no-cache" [ "=" DQUOTE *( "," OWS ) field-name *( OWS "," [ OWS		"no-cache" [ "=" DQUOTE *( "," OWS ) field-name *( OWS "," [ OWS
	field-name ] ) DQUOTE ] ) / "no-store" / "no-transform" /		field-name ] ) DQUOTE ] ) / "no-store" / "no-transform" /
	"must-revalidate" / "proxy-revalidate" / ( "max-age=" delta-seconds		"must-revalidate" / "proxy-revalidate" / ( "max-age=" delta-seconds
	) / ( "s-maxage=" delta-seconds ) / cache-extension		) / ( "s-maxage=" delta-seconds ) / cache-extension
	delta-seconds = 1*DIGIT		delta-seconds = 1*DIGIT
	extension-pragma = token [ "=" ( token / quoted-string ) ]		extension-pragma = token [ "=" ( token / quoted-string ) ]
	field-name = <field-name, defined in [Part1], Section 3.2>		field-name = <field-name, defined in [Part1], Section 3.2>
	port = <port, defined in [Part1], Section 2.7>		port = <port, defined in [Part1], Section 2.7>
	pragma-directive = "no-cache" / extension-pragma		pragma-directive = "no-cache" / extension-pragma
	pseudonym = <pseudonym, defined in [Part1], Section 8.8>		pseudonym = <pseudonym, defined in [Part1], Section 8.8>
	quoted-string = <quoted-string, defined in [Part1], Section 3.2.3>		quoted-string = <quoted-string, defined in [Part1], Section 3.2.4>
	token = <token, defined in [Part1], Section 3.2.3>		token = <token, defined in [Part1], Section 3.2.4>
	uri-host = <uri-host, defined in [Part1], Section 2.7>		uri-host = <uri-host, defined in [Part1], Section 2.7>
	warn-agent = ( uri-host [ ":" port ] ) / pseudonym		warn-agent = ( uri-host [ ":" port ] ) / pseudonym
	warn-code = 3DIGIT		warn-code = 3DIGIT
	warn-date = DQUOTE HTTP-date DQUOTE		warn-date = DQUOTE HTTP-date DQUOTE
	warn-text = quoted-string		warn-text = quoted-string
	warning-value = warn-code SP warn-agent SP warn-text [ SP warn-date		warning-value = warn-code SP warn-agent SP warn-text [ SP warn-date
	]		]
	skipping to change at page 43, line 28		skipping to change at page 43, line 28
	o <http://tools.ietf.org/wg/httpbis/trac/ticket/293>: "Interaction		o <http://tools.ietf.org/wg/httpbis/trac/ticket/293>: "Interaction
	of request and response Cache-Control"		of request and response Cache-Control"
	o <http://tools.ietf.org/wg/httpbis/trac/ticket/212>: "Refining age		o <http://tools.ietf.org/wg/httpbis/trac/ticket/212>: "Refining age
	for 1.1 proxy chains"		for 1.1 proxy chains"
	o <http://tools.ietf.org/wg/httpbis/trac/ticket/274>: "warn-code		o <http://tools.ietf.org/wg/httpbis/trac/ticket/274>: "warn-code
	registry"		registry"
			C.20. Since draft-ietf-httpbis-p6-cache-18
			None yet.
	Index		Index
	1		1
	110 Response is Stale (warn code) 31		110 Response is Stale (warn code) 31
	111 Revalidation Failed (warn code) 31		111 Revalidation Failed (warn code) 31
	112 Disconnected Operation (warn code) 31		112 Disconnected Operation (warn code) 31
	113 Heuristic Expiration (warn code) 31		113 Heuristic Expiration (warn code) 31
	199 Miscellaneous Warning (warn code) 31		199 Miscellaneous Warning (warn code) 31
	2		2
End of changes. 32 change blocks.
	50 lines changed or deleted		56 lines changed or added
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