SIP Extensions for supporting Distributed Call State

Document Type Expired Internet-Draft (sip WG)
Author Bill Marshall 
Last updated 2001-08-31
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
pdf htmlized (tools) htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
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Responsible AD (None)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document describes an extension to the Session Initiation Protocol (SIP) that enables proxies to distribute call state to user agents. The state information can be returned to the proxy when the user agent requests a change in the characteristics of the active call. By providing the ability to distribute state to the user agents where it can be securely stored, proxy servers can remain stateless for the duration of the call. This mechanism allows a proxy server to provide services that depend on call state, while still being stateless.


Bill Marshall (

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