< draft-ietf-lemonade-compress-05.txt		draft-ietf-lemonade-compress-06.txt >
	Network Working Group Arnt Gulbrandsen		Network Working Group Arnt Gulbrandsen
	Request for Comments: DRAFT Oryx Mail Systems GmbH		Request for Comments: DRAFT Oryx Mail Systems GmbH
	October 2006		November 2006
	The IMAP COMPRESS Extension		The IMAP COMPRESS Extension
	draft-ietf-lemonade-compress-05.txt		draft-ietf-lemonade-compress-06.txt
	Status of this Memo		Status of this Memo
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
	have been or will be disclosed, and any of which he or she becomes		have been or will be disclosed, and any of which he or she becomes
	aware will be disclosed, in accordance with Section 6 of BCP 79.		aware will be disclosed, in accordance with Section 6 of BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 2, line 5 ¶		skipping to change at page 2, line 5 ¶
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society 2006.		Copyright (C) The Internet Society 2006.
	Abstract		Abstract
	The COMPRESS extension allows an IMAP connection to be effectively		The COMPRESS extension allows an IMAP connection to be effectively
	and efficiently compressed.		and efficiently compressed.
	Internet-draft August 2006		Internet-draft November 2006
	Table of Contents		Table of Contents
	1. Conventions Used in This Document . . . . . . . . . . . . . . 2		1. Conventions Used in This Document . . . . . . . . . . . . . . 2
	2. Introduction and Overview . . . . . . . . . . . . . . . . . . 2		2. Introduction and Overview . . . . . . . . . . . . . . . . . . 2
	3. The COMPRESS Command . . . . . . . . . . . . . . . . . . . . . 3		3. The COMPRESS Command . . . . . . . . . . . . . . . . . . . . . 3
	4. Compression Efficiency . . . . . . . . . . . . . . . . . . . . 4		4. Compression Efficiency . . . . . . . . . . . . . . . . . . . . 5
	5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 6		5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 7
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 6		6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
	8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7		8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7		9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
	9.1. Normative References . . . . . . . . . . . . . . . . . . . 7		9.1. Normative References . . . . . . . . . . . . . . . . . . . 8
	9.2. Informative References . . . . . . . . . . . . . . . . . . 7		9.2. Informative References . . . . . . . . . . . . . . . . . . 8
	10. Author's Address . . . . . . . . . . . . . . . . . . . . . . 8		10. Author's Address . . . . . . . . . . . . . . . . . . . . . . 9
	11. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Conventions Used in This Document		1. Conventions Used in This Document
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [KEYWORDS].		document are to be interpreted as described in [RFC2119].
	Formal syntax is defined by [ABNF] as modified by [IMAP].
			Formal syntax is defined by [RFC4234] as modified by [RFC3501].
	In the example, "C:" and "S:" indicate lines sent by the client and		In the example, "C:" and "S:" indicate lines sent by the client and
	server respectively.		server respectively.
	2. Introduction and Overview		2. Introduction and Overview
	A server which supports the COMPRESS extension indicates this with		A server which supports the COMPRESS extension indicates this with
	one or more capability names consisting of "COMPRESS=" followed by a		one or more capability names consisting of "COMPRESS=" followed by a
	supported compression algorithm name as described in this document.		supported compression algorithm name as described in this document.
	The goal of COMPRESS is to reduce the bandwidth usage of IMAP.		The goal of COMPRESS is to reduce the bandwidth usage of IMAP.
	Compared to PPP/MNP compression, COMPRESS offers much better		Compared to PPP/MNP compression, COMPRESS offers much better
	compression efficiency, and can be used together with TLS, SASL		compression efficiency, and can be used together with TLS [RFC4346],
	encryption, VPNs etc. Compared to TLS compression [TLSCOMP],		SASL encryption, VPNs etc. Compared to TLS compression [RFC3749],
	COMPRESS has the following (dis)advantages:		COMPRESS has the following (dis)advantages:
	- COMPRESS can be implemented easily by IMAP servers and clients.		- COMPRESS can be implemented easily by IMAP servers and clients.
	At present, TLS compression is not widely implemented. In the		At present, TLS compression is not widely implemented. In the
	LEMONADE WG, the general consent is that libraries implementing		LEMONADE WG, the general consent is that libraries implementing
	TLS compression will not be available soon enough for LEMONADE.		TLS compression will not be available soon enough for LEMONADE.
	- IMAP compression efficiency benefits from an API that permits		- IMAP compression efficiency benefits from an API that permits
	flushing the compressor's dictionary at the right point. This is		flushing the compressor's dictionary at the right point. This is
	Internet-draft August 2006		Internet-draft November 2006
	practical for COMPRESS, whereas typical TLS libraries don't		practical for COMPRESS, whereas typical TLS libraries don't
	currently allow that.		currently allow that.
	- When a TLS librarly implements compression, all protocols that use		- When a TLS librarly implements compression, all protocols that use
	TLS automatically are compressed (in LEMONADE's case, SMTP, IMAP,		TLS automatically are compressed (in LEMONADE's case, SMTP, IMAP,
	and some notification protocol), whereas COMPRESS is specific to		and some notification protocol), whereas COMPRESS is specific to
	IMAP.		IMAP.
	In order to increase interoperation, it is desirable to have as few		In order to increase interoperation, it is desirable to have as few
	different compression algorithms as possible, so this document		different compression algorithms as possible, so this document
	specifies only one. The [DEFLATE] algorithm is standard, widely		specifies only one. The DEFLATE algorithm (defined in [RFC1951]) is
	available, unencumbered by patents and fairly efficient, so it is		standard, widely available, unencumbered by patents and fairly
	the only algorithm defined by this document.		efficient, so it is the only algorithm defined by this document.
	The extension adds one new command (COMPRESS) and no new responses.		The extension adds one new command (COMPRESS) and no new responses.
	3. The COMPRESS Command		3. The COMPRESS Command
	Arguments: Name of compression mechanism: "DEFLATE".		Arguments: Name of compression mechanism: "DEFLATE".
	Responses: None		Responses: None
	Result: OK The server will compress its responses and expects the		Result: OK The server will compress its responses and expects the
	client to compress its commands.		client to compress its commands.
	NO The server doesn't support the requested mechanism.		NO The server doesn't support the requested mechanism, or
			the mechanism is already active,
	BAD Command unknown, invalid argument, or COMPRESS already		BAD Command unknown, invalid argument, or COMPRESS already
	active.		active.
	The COMPRESS command instructs the server to use the named		The COMPRESS command instructs the server to use the named
	compression mechanism ("DEFLATE" is the only one defined) for all		compression mechanism ("DEFLATE" is the only one defined) for all
	commands and/or responses after COMPRESS.		commands and/or responses after COMPRESS.
	The client MUST NOT send any further commands until it has seen the		The client MUST NOT send any further commands until it has seen the
	result of COMPRESS. If the response was OK, the client MUST compress		result of COMPRESS. If the response was OK, the client MUST compress
	starting with the first command after COMPRESS. If the server		starting with the first command after COMPRESS. If the server
	response was BAD or NO, the client MUST NOT turn on compression.		response was BAD or NO, the client MUST NOT turn on compression.
			If the server responds NO because it knows that the same mechanism
			is active already (e.g. because TLS has negotiated the same
			mechanism), it MUST send COMPRESSIONACTIVE as resp-text-code (see
			[RFC3501] section 7.1), and the resp-text SHOULD say which layer
			compresses.
	If the server issues an OK response, the server MUST compress		If the server issues an OK response, the server MUST compress
	starting with the first response after the CRLF ending the OK		starting with the first response after the CRLF ending the OK
	response. (Responses issued by the server before the OK response		response. (Responses issued by the server before the OK response
			Internet-draft November 2006
	will, of course, still be uncompressed.) If the server issues a BAD		will, of course, still be uncompressed.) If the server issues a BAD
	or NO respnose, the server MUST NOT turn on compression.		or NO respnose, the server MUST NOT turn on compression.
	For DEFLATE (as for many other compression mechanisms), the		For DEFLATE (as for many other compression mechanisms), the
	compressor can trade speed against quality. When decompressing		compressor can trade speed against quality. When decompressing
	there isn't much of a tradeoff. Consequently, the client and server		there isn't much of a tradeoff. Consequently, the client and server
	are both free to pick the best reasonable rate of compression for		are both free to pick the best reasonable rate of compression for
	Internet-draft August 2006
	the data they send.		the data they send.
	When COMPRESS is combined with TLS or [SASL] layers, the order of		When COMPRESS is combined with TLS (see [RFC4346]) or SASL (see
	processing data to be sent SHALL be to first COMPRESS, then SASL,		[RFC4422]) security layers, the sending order of the three
	and finally TLS. When receiving data, the processing order MUST be		extensions MUST be first COMPRESS, then SASL, and finally TLS. That
	reversed. This ensures that data is compressed before it is		is, before data is transmitted it is first compressed. Second, if a
	encrypted, independent of the order in which the client issues		SASL security layer has been negotiated, the compressed data is then
	COMPRESS, AUTHENTICATE, and STARTTLS.		signed and/or encrypted accordingly. Third, if a TLS security layer
			has been negotiated, the data from the previous step is signed
			and/or encrypted accordingly. When receiving data, the processing
			order MUST be reversed. This ensures that before sending, data is
			compressed before it is encrypted, independent of the order in which
			the client issues COMPRESS, AUTHENTICATE, and STARTTLS.
	The following example illustrates how commands and responses are		The following example illustrates how commands and responses are
	compressed during a simple login sequence:		compressed during a simple login sequence:
	S: * OK [CAPABILITY IMAP4REV1 STARTTLS COMPRESS=DEFLATE]		S: * OK [CAPABILITY IMAP4REV1 STARTTLS COMPRESS=DEFLATE]
	C: a starttls		C: a starttls
	S: a OK TLS active		S: a OK TLS active
	From this point on, everything is encrypted.		From this point on, everything is encrypted.
	C: b compress deflate		C: b compress deflate
	S: b OK DEFLATE active		S: b OK DEFLATE active
	From this point on, everything is compressed before being		From this point on, everything is compressed before being
	encrypted.		encrypted.
	C: c login arnt tnra		C: c login arnt tnra
	S: c OK Logged in as arnt		S: c OK Logged in as arnt
			Internet-draft November 2006
			The following example demonstrates how a server may refuse to
			compress twice:
			S: * OK [CAPABILITY IMAP4REV1 STARTTLS COMPRESS=DEFLATE]
			C: a starttls
			S: a OK TLS active
			From this point on, everything is encrypted, and we assume
			that TLS negotiation has also enabled TLS compression (see
			[RFC3749]).
			C: b compress deflate
			S: b NO [COMPRESSIONACTIVE] DEFLATE active via TLS
	4. Compression Efficiency		4. Compression Efficiency
	This section is informative, not normative.		This section is informative, not normative.
	IMAP poses some unusual problems for a compression layer.		IMAP poses some unusual problems for a compression layer.
	Upstream is fairly simple. Most IMAP clients send the same few		Upstream is fairly simple. Most IMAP clients send the same few
	commands again and again, so any compression algorith which can		commands again and again, so any compression algorith which can
	exploit repetition works efficiently. The APPEND command is an		exploit repetition works efficiently. The APPEND command is an
	exception; clients which send many APPEND commands may want to		exception; clients which send many APPEND commands may want to
	surround large literals with flushes in the same way as is		surround large literals with flushes in the same way as is
	recommended for servers later in this section.		recommended for servers later in this section.
	Downstream has the unusual property that several kinds of data are		Downstream has the unusual property that several kinds of data are
	sent, confusing all dictionary-based compression algorithms.		sent, confusing all dictionary-based compression algorithms.
	One type is IMAP responses. These are highly compressible; zlib		One type is IMAP responses. These are highly compressible; zlib
	using its least CPU-intensive setting compresses typical responses		using its least CPU-intensive setting compresses typical responses
	to 25-40% of their original size.		to 25-40% of their original size.
	Internet-draft August 2006
	Another is email headers. These are equally compressible, and		Another is email headers. These are equally compressible, and
	benefit from using the same dictionary as the IMAP responses.		benefit from using the same dictionary as the IMAP responses.
	A third is email body text. Text is usually fairly short and		A third is email body text. Text is usually fairly short and
	includes much ASCII, so the same compression dictionary will do a		includes much ASCII, so the same compression dictionary will do a
	good job here, too. When multiple messages in the same thread are		good job here, too. When multiple messages in the same thread are
	read at the same time, quoted lines etc. can often be compressed		read at the same time, quoted lines etc. can often be compressed
	almost to zero.		almost to zero.
	Finally, attachments (non-text email bodies) are transmitted, either		Finally, attachments (non-text email bodies) are transmitted, either
	in [BINARY] form or encoded with base-64.		in binary form or encoded with base-64.
	When attachments are retrieved in [BINARY] form, DEFLATE may be able		Internet-draft November 2006
			When attachments are retrieved in binary form, DEFLATE may be able
	to compress them, but the format of the attachment is usually not		to compress them, but the format of the attachment is usually not
	IMAP-like, so the dictionary built while compressing IMAP does not		IMAP-like, so the dictionary built while compressing IMAP does not
	help. The compressor has to adapt its dictionary from IMAP to the		help. The compressor has to adapt its dictionary from IMAP to the
	attachment's format, and then back. A few file formats aren't		attachment's format, and then back. A few file formats aren't
	compressible at all using deflate, e.g. .gz, .zip and .jpg files.		compressible at all using deflate, e.g. .gz, .zip and .jpg files.
	When attachments are retrieved in base-64 form, the same problems		When attachments are retrieved in base-64 form, the same problems
	apply, but the base-64 encoding adds another problem. 8-bit		apply, but the base-64 encoding adds another problem. 8-bit
	compression algorithms such as deflate work well on 8-bit file		compression algorithms such as deflate work well on 8-bit file
	formats, however base-64 turns a file into something resembling		formats, however base-64 turns a file into something resembling
	6-bit bytes, hiding most of the 8-bit file format from the		6-bit bytes, hiding most of the 8-bit file format from the
	compressor.		compressor.
	When using the zlib library (see [DEFLATE]), the functions		When using the zlib library (see [RFC1951]), the functions
	deflateInit2(), deflate(), inflateInit2() and inflate() suffice to		deflateInit2(), deflate(), inflateInit2() and inflate() suffice to
	implement this extension. The windowBits value must be in the range		implement this extension. The windowBits value must be in the range
	-8 to -15, or else deflateInit2() uses the wrong format.		-8 to -15, or else deflateInit2() uses the wrong format.
	deflateParams() can be used to improve compression rate and resource		deflateParams() can be used to improve compression rate and resource
	use.		use.
	A client can improve downstream compression by implementing [BINARY]		A client can improve downstream compression by implementing BINARY
	and using FETCH BINARY instead of FETCH BODY. In the author's		(defined in [RFC3516]) and using FETCH BINARY instead of FETCH BODY.
	experience, the improvement ranges from 5% to 40% depending on the		In the author's experience, the improvement ranges from 5% to 40%
	attachment being downloaded.		depending on the attachment being downloaded.
	A server can improve downstream compression if it hints to the		A server can improve downstream compression if it hints to the
	compressor that the data type is about to change strongly, e.g. by		compressor that the data type is about to change strongly, e.g. by
	sending a Z_FULL_FLUSH at the start and end of large non-text		sending a Z_FULL_FLUSH at the start and end of large non-text
	literals (before and after '*CHAR8' in the definition of literal in		literals (before and after '*CHAR8' in the definition of literal in
	RFC 3501, page 86). Small literals are best left alone.		RFC 3501, page 86). Small literals are best left alone.
	A server can improve the CPU efficiency both of the server and the		A server can improve the CPU efficiency both of the server and the
	client if it adjusts the compression level (e.g. using the		client if it adjusts the compression level (e.g. using the
	deflateParams() function in zlib) at these points. A very simple		deflateParams() function in zlib) at these points. A very simple
	strategy is to change the level to 0 to at the start of a literal		strategy is to change the level to 0 to at the start of a literal
	Internet-draft August 2006
	provided the first two bytes are either 0x1F 0x8B (as in deflate-		provided the first two bytes are either 0x1F 0x8B (as in deflate-
	compressed files) or 0xFF 0xD8 (JPEG), and to keep it at 1-5 the		compressed files) or 0xFF 0xD8 (JPEG), and to keep it at 1-5 the
	rest of the time.		rest of the time.
	Note that when using TLS, compression may actually decrease the CPU		Note that when using TLS, compression may actually decrease the CPU
	usage, depending on which algorithms are used in TLS. This is		usage, depending on which algorithms are used in TLS. This is
	because fewer bytes need to be encrypted, and encryption is		because fewer bytes need to be encrypted, and encryption is
	generally more expensive than compression.		generally more expensive than compression.
			Internet-draft November 2006
	5. Formal Syntax		5. Formal Syntax
	The following syntax specification uses the Augmented Backus-Naur		The following syntax specification uses the Augmented Backus-Naur
	Form (ABNF) notation as specified in [ABNF]. Non-terminals		Form (ABNF) notation as specified in [RFC4234]. [RFC4234] defines SP
	referenced but not defined below are as defined by [ABNF] (SP, CRLF)		and [RFC3501] defines command-any, capability and resp-text-code.
	or [IMAP] (all others).
	Except as noted otherwise, all alphabetic characters are case-		Except as noted otherwise, all alphabetic characters are case-
	insensitive. The use of upper or lower case characters to define		insensitive. The use of upper or lower case characters to define
	token strings is for editorial clarity only. Implementations MUST		token strings is for editorial clarity only. Implementations MUST
	accept these strings in a case-insensitive fashion.		accept these strings in a case-insensitive fashion.
	command-any =/ compress		command-any =/ compress
	compress = "COMPRESS" SP algorithm		compress = "COMPRESS" SP algorithm
	capability =/ "COMPRESS=" algorithm		capability =/ "COMPRESS=" algorithm
	;; multiple COMPRESS capabilities allowed		;; multiple COMPRESS capabilities allowed
	algorithm = "DEFLATE"		algorithm = "DEFLATE"
			resp-text-code =/ "COMPRESSIONACTIVE"
	Note that due the syntax of capability names, future algorithm names		Note that due the syntax of capability names, future algorithm names
	must be atoms.		must be atoms.
	6. Security Considerations		6. Security Considerations
	As for [TLSCOMP] RFC 3749.		As for TLS compression [RFC3749].
	7. IANA Considerations		7. IANA Considerations
	The IANA is requested to add COMPRESS=DEFLATE the list of IMAP		The IANA is requested to add COMPRESS=DEFLATE the list of IMAP
	extensions.		extensions.
	Note to IANA: This RFC does not specify the creation of a registry		Note to IANA: This RFC does not specify the creation of a registry
	for compression mechanisms. The current feeling of the IMAP		for compression mechanisms. The current feeling of the IMAP
	community is that is is unlikely that another compression mechanism		community is that is is unlikely that another compression mechanism
			will be added in the future. However, if this RFC is extended in the
			future by another RFC, and another compression mechanism is added at
			that time, it would then be appropriate to create a registry.
	Internet-draft August 2006		Internet-draft November 2006
	algorithm will be added in the future. However, if this RFC is
	extended in the future by another RFC, and another compression is
	added at that time, it would then be appropriate to create a
	registry.
	8. Acknowledgements		8. Acknowledgements
	Eric Burger, Dave Cridland, Tony Finch, Ned Freed, Philip Guenther,		Eric Burger, Dave Cridland, Tony Finch, Ned Freed, Philip Guenther,
	Randall Gellens, Tony Hansen, Stephane Maes, Alexey Melnikov, Lyndon		Randall Gellens, Tony Hansen, Stephane Maes, Alexey Melnikov, Lyndon
	Nerenberg and Zoltan Ordogh have all helped with this document.		Nerenberg and Zoltan Ordogh have all helped with this document.
	The author would also like to thank various people in the rooms at		The author would also like to thank various people in the rooms at
	meetings, whose help is real, but not reflected in the author's		meetings, whose help is real, but not reflected in the author's
	mailbox.		mailbox.
	9. References		9. References
	9.1. Normative References		9.1. Normative References
	[ABNF] Crocker, Overell, "Augmented BNF for Syntax		[RFC1951] Deutsch, "DEFLATE Compressed Data Format Specification
	Specifications: ABNF", RFC 4234, Brandenburg		version 1.3", RFC 1951, Aladdin Enterprises, May 1996.
	Internetworking, Demon Internet Ltd, October 2005.
	[IMAP] Crispin, "Internet Message Access Protocol - Version
	4rev1", RFC 3501, University of Washington, June 2003.
	[KEYWORDS] Bradner, "Key words for use in RFCs to Indicate		[RFC2119] Bradner, "Key words for use in RFCs to Indicate
	Requirement Levels", RFC 2119, Harvard University, March		Requirement Levels", RFC 2119, Harvard University, March
	1997.		1997.
	[DEFLATE] Deutsch, "DEFLATE Compressed Data Format Specification		[RFC3501] Crispin, "Internet Message Access Protocol - Version
	version 1.3", RFC 1951, Aladdin Enterprises, May 1996.		4rev1", RFC 3501, University of Washington, June 2003.
			[RFC4234] Crocker, Overell, "Augmented BNF for Syntax
			Specifications: ABNF", RFC 4234, Brandenburg
			Internetworking, Demon Internet Ltd, October 2005.
	9.2. Informative References		9.2. Informative References
	[TLSCOMP] Hollenbeck, "Transport Layer Security Protocol		[RFC3516] Nerenberg, "IMAP4 Binary Content Extension", RFC 3516,
	Compression Methods", RFC 3749, VeriSign, May 2004.		Orthanc Systems, April 2003.
	[SASL] Melnikov, Zeilenga, "Simple Authentication and Security		[RFC3749] Hollenbeck, "Transport Layer Security Protocol
	Layer (SASL)", RFC 4422, Isode Limited, June 2006		Compression Methods", RFC 3749, VeriSign, May 2004.
	[BINARY] Nerenberg, "IMAP4 Binary Content Extension", Orthanc		[RFC4346] Dierks, Rescorla, "The Transport Layer Security (TLS)
			Protocol, Version 1.1", RFC 4346, April 2006.
	Internet-draft August 2006		[RFC4422] Melnikov, Zeilenga, "Simple Authentication and Security
			Layer (SASL)", RFC 4422, Isode Limited, June 2006
	Systems, April 2003.		Internet-draft November 2006
	10. Author's Address		10. Author's Address
	Arnt Gulbrandsen		Arnt Gulbrandsen
	Oryx Mail Systems GmbH		Oryx Mail Systems GmbH
	Schweppermannstr. 8		Schweppermannstr. 8
	D-81671 Muenchen		D-81671 Muenchen
	Germany		Germany
	Fax: +49 89 4502 9758		Fax: +49 89 4502 9758
	Email: arnt@oryx.com		Email: arnt@oryx.com
	11. Open Issues
	What text and numbers are needed wrt. compression levels? A bit of
	solid information is not amiss.
	Intellectual Property Statement		Intellectual Property Statement
	The IETF takes no position regarding the validity or scope of any		The IETF takes no position regarding the validity or scope of any
	Intellectual Property Rights or other rights that might be claimed		Intellectual Property Rights or other rights that might be claimed
	to pertain to the implementation or use of the technology described		to pertain to the implementation or use of the technology described
	in this document or the extent to which any license under such		in this document or the extent to which any license under such
	rights might or might not be available; nor does it represent that		rights might or might not be available; nor does it represent that
	it has made any independent effort to identify any such rights.		it has made any independent effort to identify any such rights.
	Information on the procedures with respect to rights in RFC		Information on the procedures with respect to rights in RFC
	documents can be found in BCP 78 and BCP 79.		documents can be found in BCP 78 and BCP 79.
	skipping to change at page 9, line 5 ¶		skipping to change at page 9, line 43 ¶
	of such proprietary rights by implementers or users of this		of such proprietary rights by implementers or users of this
	specification can be obtained from the IETF on-line IPR repository		specification can be obtained from the IETF on-line IPR repository
	at http://www.ietf.org/ipr.		at http://www.ietf.org/ipr.
	The IETF invites any interested party to bring to its attention any		The IETF invites any interested party to bring to its attention any
	copyrights, patents or patent applications, or other proprietary		copyrights, patents or patent applications, or other proprietary
	rights that may cover technology that may be required to implement		rights that may cover technology that may be required to implement
	this standard. Please address the information to the IETF at ietf-		this standard. Please address the information to the IETF at ietf-
	ipr@ietf.org.		ipr@ietf.org.
	Internet-draft August 2006
	Copyright Statement		Copyright Statement
	Copyright (C) The Internet Society (2006).		Copyright (C) The Internet Society (2006).
	This document is subject to the rights, licenses and restrictions		This document is subject to the rights, licenses and restrictions
	contained in BCP 78, and except as set forth therein, the authors		contained in BCP 78, and except as set forth therein, the authors
	retain all their rights.		retain all their rights.
			Internet-draft November 2006
	Disclaimer of Validity		Disclaimer of Validity
	This document and the information contained herein are provided on		This document and the information contained herein are provided on
	an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE		an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
	REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE		REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
	INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR		INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF		IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
	THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED		THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
	WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.		WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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