RFC - 4028

Session Timers in the Session Initiation Protocol (SIP)

Original:	ftp://ftp.isi.edu/in-notes/rfc4028.txt
Authors:	S. Donovan [Cisco Systems], J. Rosenberg [Cisco Systems]
Date:	April 2005
Category:	Proposed Standard

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Referred by:	3 RFC
Refers to:	9 RFC

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Status

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.

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