--- 1/draft-ietf-sipcore-refer-clarifications-00.txt 2015-01-21 13:14:56.536158228 -0800 +++ 2/draft-ietf-sipcore-refer-clarifications-01.txt 2015-01-21 13:14:56.552158619 -0800 @@ -1,19 +1,19 @@ Network Working Group R. Sparks Internet-Draft Oracle Updates: 3515 (if approved) A. Roach 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 - draft-ietf-sipcore-refer-clarifications-00 + draft-ietf-sipcore-refer-clarifications-01 Abstract The SIP REFER method relies on the SIP-Specific Event Notification Framework. That framework was revised by RFC6665. This document highlights the implications of the requirement changes in RFC6665, and updates the definition of the REFER method, RFC3515, to clarify and disambiguate the impact of those changes. Status of This Memo @@ -24,49 +24,50 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may 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 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 (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. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Conventions and Definitions . . . . . . . . . . . . . . . . . 2 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3. Use of GRUU is mandatory . . . . . . . . . . . . . . . . . . 2 + 3. Use of GRUU is mandatory . . . . . . . . . . . . . . . . . . 3 4. Dialog reuse is prohibited . . . . . . . . . . . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 - 7. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 4 - 8.2. Informative References . . . . . . . . . . . . . . . . . 5 + 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 + 8. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 4 + 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 + 9.1. Normative References . . . . . . . . . . . . . . . . . . 5 + 9.2. Informative References . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Introduction @@ -76,20 +77,32 @@ and updates [RFC3515] to clarify and disambiguate the impact of those changes. Accepting a REFER request (without invoking extensions) results in an implicit SIP-Events subscription. If that REFER was part of an existing dialog, the implicit subscription creates a new, problematic dialog-usage within that dialog [RFC5057]. The "norefersub" extension defined in [RFC4488] asks to suppress this implicit 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 Section 4.5.1 of [RFC6665] makes GRUU [RFC5627] mandatory for notifiers to implement and use as the local target in the subscription created by the REFER request. A user agent accepting a REFER that creates a subscription MUST populate its Contact header field with a GRUU. A UA that will accept a REFER request needs to include a GRUU in the @@ -147,28 +160,38 @@ 5. Security Considerations This document introduces no new security considerations directly. The updated considerations in [RFC6665] apply to the implicit subscription created by an accepted REFER request. 6. IANA Considerations 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 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- sipcore-refer-clarifications-00 - Attempted to improve the accuracy of the Abstract and Introduction without diluting the essential point of the document. Added an informative reference to RFC5057. Adjusted text to more reflect what RFC6665 (as clarified by draft-roach-sipcore-6665-clarification) actually requires, and added a normative reference to that clarification draft. Specifically, the requirement for the _sender_ of a REFER to @@ -171,23 +194,23 @@ Adjusted text to more reflect what RFC6665 (as clarified by draft-roach-sipcore-6665-clarification) actually requires, and added a normative reference to that clarification draft. Specifically, the requirement for the _sender_ of a REFER to use a GRUU as its local targetwas removed. Clarified why the explicit-subscription extensions relieve an in-dialog REFERer from the 6665 requirements for using GRUU as its contact in the INVITE dialog. -8. References +9. References -8.1. Normative References +9.1. Normative References [I-D.roach-sipcore-6665-clarification] Roach, A., "A clarification on the use of Globally Routable User Agent URIs (GRUUs) in the Session Initiation Protocol (SIP) Event Notification Framework", draft-roach- sipcore-6665-clarification-00 (work in progress), October 2014. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. @@ -204,21 +227,21 @@ Identification in the Session Initiation Protocol (SIP)", RFC 4538, June 2006. [RFC5627] Rosenberg, J., "Obtaining and Using Globally Routable User Agent URIs (GRUUs) in the Session Initiation Protocol (SIP)", RFC 5627, October 2009. [RFC6665] Roach, A., "SIP-Specific Event Notification", RFC 6665, July 2012. -8.2. Informative References +9.2. Informative References [I-D.ietf-sipcore-refer-explicit-subscription] Sparks, R., "Explicit Subscriptions for the REFER Method", draft-ietf-sipcore-refer-explicit-subscription-00 (work in progress), November 2014. [RFC4488] Levin, O., "Suppression of Session Initiation Protocol (SIP) REFER Method Implicit Subscription", RFC 4488, May 2006.