draft-ietf-sipcore-refer-clarifications-00.txt		draft-ietf-sipcore-refer-clarifications-01.txt
	Network Working Group R. Sparks		Network Working Group R. Sparks
	Internet-Draft Oracle		Internet-Draft Oracle
	Updates: 3515 (if approved) A. Roach		Updates: 3515 (if approved) A. Roach
	Intended status: Standards Track Mozilla		Intended status: Standards Track Mozilla
	Expires: May 25, 2015 November 21, 2014		Expires: July 25, 2015 January 21, 2015
	Clarifications for the use of REFER with RFC6665		Clarifications for the use of REFER with RFC6665
	draft-ietf-sipcore-refer-clarifications-00		draft-ietf-sipcore-refer-clarifications-01
	Abstract		Abstract
	The SIP REFER method relies on the SIP-Specific Event Notification		The SIP REFER method relies on the SIP-Specific Event Notification
	Framework. That framework was revised by RFC6665. This document		Framework. That framework was revised by RFC6665. This document
	highlights the implications of the requirement changes in RFC6665,		highlights the implications of the requirement changes in RFC6665,
	and updates the definition of the REFER method, RFC3515, to clarify		and updates the definition of the REFER method, RFC3515, to clarify
	and disambiguate the impact of those changes.		and disambiguate the impact of those changes.
	Status of This Memo		Status of This Memo
	skipping to change at page 1, line 35		skipping to change at page 1, line 35
	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 May 25, 2015.		This Internet-Draft will expire on July 25, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2015 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
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Conventions and Definitions . . . . . . . . . . . . . . . . . 2		1. Conventions and Definitions . . . . . . . . . . . . . . . . . 2
	2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	3. Use of GRUU is mandatory . . . . . . . . . . . . . . . . . . 2		3. Use of GRUU is mandatory . . . . . . . . . . . . . . . . . . 3
	4. Dialog reuse is prohibited . . . . . . . . . . . . . . . . . 3		4. Dialog reuse is prohibited . . . . . . . . . . . . . . . . . 3
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 4		5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
	7. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 4		7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4		8. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 4
	8.1. Normative References . . . . . . . . . . . . . . . . . . 4		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
	8.2. Informative References . . . . . . . . . . . . . . . . . 5		9.1. Normative References . . . . . . . . . . . . . . . . . . 5
			9.2. Informative References . . . . . . . . . . . . . . . . . 6
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
	1. Conventions and Definitions		1. Conventions and Definitions
	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 [RFC2119].		document are to be interpreted as described in [RFC2119].
	2. Introduction		2. Introduction
	skipping to change at page 2, line 42		skipping to change at page 2, line 43
	and updates [RFC3515] to clarify and disambiguate the impact of those		and updates [RFC3515] to clarify and disambiguate the impact of those
	changes.		changes.
	Accepting a REFER request (without invoking extensions) results in an		Accepting a REFER request (without invoking extensions) results in an
	implicit SIP-Events subscription. If that REFER was part of an		implicit SIP-Events subscription. If that REFER was part of an
	existing dialog, the implicit subscription creates a new, problematic		existing dialog, the implicit subscription creates a new, problematic
	dialog-usage within that dialog [RFC5057]. The "norefersub"		dialog-usage within that dialog [RFC5057]. The "norefersub"
	extension defined in [RFC4488] asks to suppress this implicit		extension defined in [RFC4488] asks to suppress this implicit
	subscription, but cannot prevent its creation.		subscription, but cannot prevent its creation.
			There are implementations in some known specialized environments
			(such as 3gpp) that use out-of-signalling agreements to ensure that
			in-dialog REFER requests using the RFC4488 extension do not create a
			new subscription inside that dialog. In the 3gpp environment, the
			behavior is based on capabilities advertised using media feature
			tags. That mechanism does not, however, prevent additional dialog
			usages when interoperating with implementations that do not support
			the mechanism. The extensions in
			[I-D.ietf-sipcore-refer-explicit-subscription] provide a standardized
			mechanism that allows avoiding any additional dialog usage.
	3. Use of GRUU is mandatory		3. Use of GRUU is mandatory
	Section 4.5.1 of [RFC6665] makes GRUU [RFC5627] mandatory for		Section 4.5.1 of [RFC6665] makes GRUU [RFC5627] mandatory for
	notifiers to implement and use as the local target in the		notifiers to implement and use as the local target in the
	subscription created by the REFER request.		subscription created by the REFER request.
	A user agent accepting a REFER that creates a subscription MUST		A user agent accepting a REFER that creates a subscription MUST
	populate its Contact header field with a GRUU.		populate its Contact header field with a GRUU.
	A UA that will accept a REFER request needs to include a GRUU in the		A UA that will accept a REFER request needs to include a GRUU in the
	skipping to change at page 4, line 18		skipping to change at page 4, line 31
	5. Security Considerations		5. Security Considerations
	This document introduces no new security considerations directly.		This document introduces no new security considerations directly.
	The updated considerations in [RFC6665] apply to the implicit		The updated considerations in [RFC6665] apply to the implicit
	subscription created by an accepted REFER request.		subscription created by an accepted REFER request.
	6. IANA Considerations		6. IANA Considerations
	This document has no actions for IANA.		This document has no actions for IANA.
	7. Changelog		7. Acknowledgements
			Christer Holmberg provided the formulation for the final paragraph of
			the introduction. Christer Holmberg and Ivo Sedlacek provided
			detailed comments during working group discussion of the document.
			8. Changelog
	RFC Editor - please remove this section when formatting this document		RFC Editor - please remove this section when formatting this document
	as an RFC		as an RFC
			-00 to -01
			Added the 3rd paragraph to the introduction per extensive list
			discussion
	draft-sparks-sipcore-refer-clarifications-05 to draft-ietf-		draft-sparks-sipcore-refer-clarifications-05 to draft-ietf-
	sipcore-refer-clarifications-00		sipcore-refer-clarifications-00
	Attempted to improve the accuracy of the Abstract and		Attempted to improve the accuracy of the Abstract and
	Introduction without diluting the essential point of the		Introduction without diluting the essential point of the
	document.		document.
	Added an informative reference to RFC5057.		Added an informative reference to RFC5057.
	Adjusted text to more reflect what RFC6665 (as clarified by		Adjusted text to more reflect what RFC6665 (as clarified by
	draft-roach-sipcore-6665-clarification) actually requires, and		draft-roach-sipcore-6665-clarification) actually requires, and
	added a normative reference to that clarification draft.		added a normative reference to that clarification draft.
	Specifically, the requirement for the _sender_ of a REFER to		Specifically, the requirement for the _sender_ of a REFER to
	skipping to change at page 4, line 42		skipping to change at page 5, line 20
	Adjusted text to more reflect what RFC6665 (as clarified by		Adjusted text to more reflect what RFC6665 (as clarified by
	draft-roach-sipcore-6665-clarification) actually requires, and		draft-roach-sipcore-6665-clarification) actually requires, and
	added a normative reference to that clarification draft.		added a normative reference to that clarification draft.
	Specifically, the requirement for the _sender_ of a REFER to		Specifically, the requirement for the _sender_ of a REFER to
	use a GRUU as its local targetwas removed.		use a GRUU as its local targetwas removed.
	Clarified why the explicit-subscription extensions relieve an		Clarified why the explicit-subscription extensions relieve an
	in-dialog REFERer from the 6665 requirements for using GRUU as		in-dialog REFERer from the 6665 requirements for using GRUU as
	its contact in the INVITE dialog.		its contact in the INVITE dialog.
	8. References		9. References
	8.1. Normative References		9.1. Normative References
	[I-D.roach-sipcore-6665-clarification]		[I-D.roach-sipcore-6665-clarification]
	Roach, A., "A clarification on the use of Globally		Roach, A., "A clarification on the use of Globally
	Routable User Agent URIs (GRUUs) in the Session Initiation		Routable User Agent URIs (GRUUs) in the Session Initiation
	Protocol (SIP) Event Notification Framework", draft-roach-		Protocol (SIP) Event Notification Framework", draft-roach-
	sipcore-6665-clarification-00 (work in progress), October		sipcore-6665-clarification-00 (work in progress), October
	2014.		2014.
	[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.
	skipping to change at page 5, line 34		skipping to change at page 6, line 5
	Identification in the Session Initiation Protocol (SIP)",		Identification in the Session Initiation Protocol (SIP)",
	RFC 4538, June 2006.		RFC 4538, June 2006.
	[RFC5627] Rosenberg, J., "Obtaining and Using Globally Routable User		[RFC5627] Rosenberg, J., "Obtaining and Using Globally Routable User
	Agent URIs (GRUUs) in the Session Initiation Protocol		Agent URIs (GRUUs) in the Session Initiation Protocol
	(SIP)", RFC 5627, October 2009.		(SIP)", RFC 5627, October 2009.
	[RFC6665] Roach, A., "SIP-Specific Event Notification", RFC 6665,		[RFC6665] Roach, A., "SIP-Specific Event Notification", RFC 6665,
	July 2012.		July 2012.
	8.2. Informative References		9.2. Informative References
	[I-D.ietf-sipcore-refer-explicit-subscription]		[I-D.ietf-sipcore-refer-explicit-subscription]
	Sparks, R., "Explicit Subscriptions for the REFER Method",		Sparks, R., "Explicit Subscriptions for the REFER Method",
	draft-ietf-sipcore-refer-explicit-subscription-00 (work in		draft-ietf-sipcore-refer-explicit-subscription-00 (work in
	progress), November 2014.		progress), November 2014.
	[RFC4488] Levin, O., "Suppression of Session Initiation Protocol		[RFC4488] Levin, O., "Suppression of Session Initiation Protocol
	(SIP) REFER Method Implicit Subscription", RFC 4488, May		(SIP) REFER Method Implicit Subscription", RFC 4488, May
	2006.		2006.
End of changes. 13 change blocks.
	14 lines changed or deleted		37 lines changed or added
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