Network Working Group                                        A. B. Roach
Internet-Draft                                                   Mozilla
Updates: 6665 (if approved)                             October 27, 2014
Intended status: Standards Track
Expires: April 30, 2015


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

Abstract

   Experience since the publication of the most recent SIP Events
   framework has shown that there is room for interpretation around the
   use of Globally Routable User Agent URIs in that specification.  This
   document clarifies the intended behavior.

   This document updates RFC 6665.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on April 30, 2015.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   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.  Clarification of GRUU Handling  . . . . . . . . . . . . . . .   2
   2.  Security Considerations . . . . . . . . . . . . . . . . . . .   2
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Normative References  . . . . . . . . . . . . . . . . . . . .   3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   3

1.  Clarification of GRUU Handling

   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].

   [RFC6665] section 4.5.1 contains the following normative requirement
   on implementations:

      Notifiers MUST implement the Globally Routable User Agent URI
      (GRUU) extension defined in [RFC5627], and MUST use a GRUU as
      their local target.  This allows subscribers to explicitly target
      desired devices.

   The second sentence of this paragraph attempted to set context for
   the normative statement: the reason GRUUs are required in this
   context is to allow you to send SUBSCRIBE or REFER requests to a
   specific user agent, with the target of the subscription request
   being something like an INVITE dialog on that device.  Consequently,
   the requirement to include a GRUU as a local target applies not just
   to the local target for SUBSCRIBE-created dialogs, but for *all*
   dialogs, even those created by INVITE.

   However, this requirement has been interpreted in a variety of ways
   by implementors, so a clarification is in order.

   This document updates [RFC6665] to clarify the actual requirement:
   "Notifiers MUST implement the Globally Routable User Agent URI (GRUU)
   extension defined in [RFC5627], and MUST use a GRUU as their local
   target for all dialog-forming methods and all target-refresh methods.
   This specifically includes dialogs created by the INVITE method."

2.  Security Considerations

   This mechanism does not introduce any security issues beyond those
   discussed in [RFC6665].



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3.  IANA Considerations

   This document requests no actions of IANA.

4.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [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.B., "SIP-Specific Event Notification", RFC 6665,
              July 2012.

Author's Address

   Adam Roach
   Mozilla
   Dallas, TX
   US

   Phone: +1 650 903 0800 x863
   Email: adam@nostrum.com

























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