SIP-Specific Event Notification
RFC 6665

Internet Engineering Task Force (IETF)                        A.B. Roach
Request for Comments: 6665                                       Tekelec
Obsoletes: 3265                                                July 2012
Updates: 3261, 4660
Category: Standards Track
ISSN: 2070-1721

                    SIP-Specific Event Notification

Abstract

   This document describes an extension to the Session Initiation
   Protocol (SIP) defined by RFC 3261.  The purpose of this extension is
   to provide an extensible framework by which SIP nodes can request
   notification from remote nodes indicating that certain events have
   occurred.

   Note that the event notification mechanisms defined herein are NOT
   intended to be a general-purpose infrastructure for all classes of
   event subscription and notification.

   This document represents a backwards-compatible improvement on the
   original mechanism described by RFC 3265, taking into account several
   years of implementation experience.  Accordingly, this document
   obsoletes RFC 3265.  This document also updates RFC 4660 slightly to
   accommodate some small changes to the mechanism that were discussed
   in that document.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6665.

Roach                        Standards Track                    [Page 1]
RFC 6665             SIP-Specific Event Notification           July 2012

Copyright Notice

   Copyright (c) 2012 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.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
     1.1.  Overview of Operation  . . . . . . . . . . . . . . . . . .  5
     1.2.  Documentation Conventions  . . . . . . . . . . . . . . . .  6
   2.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . .  6
   3.  SIP Methods for Event Notification . . . . . . . . . . . . . .  7
     3.1.  SUBSCRIBE  . . . . . . . . . . . . . . . . . . . . . . . .  7
       3.1.1.  Subscription Duration  . . . . . . . . . . . . . . . .  7
       3.1.2.  Identification of Subscribed Events and Event
               Classes  . . . . . . . . . . . . . . . . . . . . . . .  8
       3.1.3.  Additional SUBSCRIBE Header Field Values . . . . . . .  9
     3.2.  NOTIFY . . . . . . . . . . . . . . . . . . . . . . . . . .  9
       3.2.1.  Identification of Reported Events, Event Classes,
               and Current State  . . . . . . . . . . . . . . . . . .  9
   4.  Node Behavior  . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.1.  Subscriber Behavior  . . . . . . . . . . . . . . . . . . . 10
       4.1.1.  Detecting Support for SIP Events . . . . . . . . . . . 10
       4.1.2.  Creating and Maintaining Subscriptions . . . . . . . . 10
       4.1.3.  Receiving and Processing State Information . . . . . . 14
       4.1.4.  Forking of SUBSCRIBE Requests  . . . . . . . . . . . . 16
     4.2.  Notifier Behavior  . . . . . . . . . . . . . . . . . . . . 17
       4.2.1.  Subscription Establishment and Maintenance . . . . . . 17
       4.2.2.  Sending State Information to Subscribers . . . . . . . 20
       4.2.3.  PSTN/Internet Interworking (PINT) Compatibility  . . . 23
     4.3.  Proxy Behavior . . . . . . . . . . . . . . . . . . . . . . 23
     4.4.  Common Behavior  . . . . . . . . . . . . . . . . . . . . . 24
       4.4.1.  Dialog Creation and Termination  . . . . . . . . . . . 24
       4.4.2.  Notifier Migration . . . . . . . . . . . . . . . . . . 24
       4.4.3.  Polling Resource State . . . . . . . . . . . . . . . . 25
       4.4.4.  "Allow-Events" Header Field Usage  . . . . . . . . . . 26
     4.5.  Targeting Subscriptions at Devices . . . . . . . . . . . . 26
       4.5.1.  Using GRUUs to Route to Devices  . . . . . . . . . . . 27