RFC 3857 (rfc3857) - Page 2 of 20

A Watcher Information Event Template-Package for the Session Initiation Protocol (SIP)

RFC 3857                  Watcher Information                August 2004


Table of Contents

   1.   Introduction ........................................    2
   2.   Terminology .........................................    3
   3.   Usage Scenarios .....................................    3
        3.1.  Presence Authorization ........................    4
        3.2.  Blacklist Alerts ..............................    5
   4.   Package Definition ..................................    5
        4.1.  Event Package Name ............................    5
        4.2.  Event Package Parameters ......................    5
        4.3.  SUBSCRIBE Bodies ..............................    6
        4.4.  Subscription Duration .........................    6
        4.5.  NOTIFY Bodies .................................    7
        4.6.  Notifier Processing of SUBSCRIBE Requests......    7
        4.7.  Notifier Generation of NOTIFY Requests ........    8
              4.7.1.  The Subscription State Machine.........    9
              4.7.2.  Applying the State Machine.............   11
        4.8.  Subscriber Processing of NOTIFY Requests ......   12
        4.9.  Handling of Forked Requests ...................   12
        4.10. Rate of Notifications .........................   13
        4.11. State Agents ..................................   13
   5.   Example Usage .......................................   14
   6.   Security Considerations .............................   17
        6.1.  Denial of Service Attacks .....................   17
        6.2.  Divulging Sensitive Information ...............   17
   7.   IANA Considerations .................................   18
   8.   Acknowledgements ....................................   18
   9.   Normative References ................................   18
   10.  Informative References ..............................   19
   11.  Author's Address ....................................   19
   12.  Full Copyright Statement ............................   20

1.  Introduction

   The Session Initiation Protocol (SIP) event framework is described in
   RFC 3265 [1].  It defines a generic framework for subscription to,
   and notification of, events related to SIP systems.  The framework
   defines the methods SUBSCRIBE and NOTIFY, and introduces the notion
   of a package.  A package is a concrete application of the event
   framework to a particular class of events.  Packages have been
   defined for user presence [5], for example.

   This document defines a "template-package" within the SIP event
   framework.  A template-package has all the properties of a regular
   SIP event package.  However, it is always associated with some other
   event package, and can always be applied to any event package,
   including the template-package itself.




Rosenberg                   Standards Track