Subject: Protocol Action: An Extension to the Session Initiation Protocol (SIP) for Symmetric Response Routing to Proposed Standard

From: The IESG <[email-masked]>
Date: Tue, 08 Jul 2003 11:31:59 -0400

The IESG has approved the Internet-Draft 'An Extension to the Session
Initiation Protocol (SIP) for Symmetric Response Routing'
<draft-ietf-sip-symmetric-response-01.txt> as a Proposed Standard.
This document is the product of the Session Initiation Protocol
Working Group. The IESG contact persons are Allison Mankin and Jon
Peterson.

Technical Summary

The Session Initiation Protocol (SIP) operates over UDP and TCP. When
used with UDP, responses to requests are returned to the source
address the request came from, and to the port written into the
topmost Via header field value of the request. This behavior is not
desirable in many cases, most notably, when the client is behind a
Network Address Translator (NAT). This extension defines a new
parameter for the Via header field, called "rport", that allows a
client to request that the server send the response back to the
source IP address and port where the request came from.

Working Group Summary

The Working Group supported the advancement of this document.
There were reviews by working group members.

Protocol Quality

The document includes an analysis of the work in the perspective
of the IAB's UNSAF Considerations. The review for the IESG was
carried out by Allison Mankin.