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Session Timers in the Session Initiation Protocol (SIP) (RFC4028)

IP.com Disclosure Number: IPCOM000124593D
Original Publication Date: 2005-Apr-01
Included in the Prior Art Database: 2005-Apr-29
Document File: 28 page(s) / 65K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

S. Donovan: AUTHOR [+2]

Abstract

This document defines an extension to the Session Initiation Protocol (SIP). This extension allows for a periodic refresh of SIP sessions through a re-INVITE or UPDATE request. The refresh allows both user agents and proxies to determine whether the SIP session is still active. The extension defines two new header fields: Session-Expires, which conveys the lifetime of the session, and Min-SE, which conveys the minimum allowed value for the session timer.

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This is the abbreviated version, containing approximately 4% of the total text.

Network Working Group                                         S. Donovan
Request for Comments: 4028                                  J. Rosenberg
Category: Standards Track                                  Cisco Systems
                                                              April 2005


        Session Timers in the Session Initiation Protocol (SIP)

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document defines an extension to the Session Initiation Protocol
   (SIP).  This extension allows for a periodic refresh of SIP sessions
   through a re-INVITE or UPDATE request.  The refresh allows both user
   agents and proxies to determine whether the SIP session is still
   active.  The extension defines two new header fields:
   Session-Expires, which conveys the lifetime of the session, and
   Min-SE, which conveys the minimum allowed value for the session
   timer.

Donovan & Rosenberg         Standards Track                     [Page 1]
RFC 4028                     Session Timer                    April 2005


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Overview of Operation  . . . . . . . . . . . . . . . . . . .   4
   4.  Session-Expires Header Field Definition  . . . . . . . . . .   6
   5.  Min-SE Header Field Definition . . . . . . . . . . . . . . .   8
   6.  422 Response Code Definition . . . . . . . . . . . . . . . .   8
   7.  UAC Behavior . . . . . . . . . . . . . . . . . . . . . . . .   9
       7.1.  Generating an Initial Session Refresh Request  . . . .   9
       7.2.  Processing a 2xx Response  . . . . . . . . . . . . . .   9
       7.3.  Processing a 422 Response  . . . . . . . . . . . . . .  11
       7.4.  Generating Subsequent Session Refresh Requests . . . .  11
   8.  Proxy Behavior . . . . . . . . . . . . . . . . . . . . . . .  12
       8.1.  Processing of Requests . . . . . . . . . . . . . . . .  13
       8.2.  Processing of Responses  . . . . . . . . . . . . . . .  14
       8.3.  Session Expiration . . . . . . . . . . . . . . . . . .  15
   9.  UAS Behavior . . . . . . . . . . . . . . . . . . . . . . . .  15
   10. Pe...