Correct transaction handling for 200 responses to Session Initiation Protocol INVITE requests

Document Type Replaced Internet-Draft (individual)
Last updated 2010-01-13 (latest revision 2009-09-12)
Replaces draft-sparks-sip-invfix
Replaced by RFC 6026
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document normatively updates RFC 3261, the Session Initiation Protocol (SIP), to address an error in the specified handling of success (200 class) responses to INVITE requests. Elements following RFC 3261 exactly will misidentify retransmissions of the request as a new, unassociated, request. The correction involves modifying the INVITE transaction state machines. The correction also changes the way responses that cannot be matched to an existing transaction are handled to address a security risk.


Robert Sparks (
Theo Zourzouvillys (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)