Requirements for Connection Reuse in the Session Initiation Protocol (SIP)

Document Type Expired Internet-Draft (sipping WG)
Author Rohan Mahy 
Last updated 2002-10-28
Replaces draft-mahy-sipping-connect-reuse-reqs
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
plain text pdf htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


When SIP entities use a connection oriented protocol to send a request, they typically originate their connections from an ephemeral port. The SIP protocol includes mechanisms which insure that responses to a request, and new requests sent in the original direction reuse an existing connection. However, new requests sent in the opposite direction are unlikely to reuse the existing connection. This frequently causes a pair of SIP entities to use one connection for requests sent in each direction, and can result in potential scaling and performance problems. This document presents requirements for addressing this shortcoming, and separately proposes an example mechanism which addresses this deficiency.


Rohan Mahy (

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