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SIP Conventions for UAs with Outbound Only Connections

Document Type Replaced Internet-Draft (individual)
Expired & archived
Authors Cullen Fluffy Jennings , Alan Hawrylyshen
Last updated 2005-07-22 (Latest revision 2005-02-22)
Replaced by RFC 5626
RFC stream (None)
Intended RFC status (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Replaced by draft-ietf-sip-outbound
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


Often with SIP a request can only be routed over an existing connection or flow, such as when there is a firewall or network address translation (NAT) device in the network path. TLS is also affected when the user agent (UA) does not have a certificate suitable for mutual TLS authentication. This draft addresses how user agents and proxies need to behave to work in these environments. This work shows how existing SIP mechanisms can be used to allow the UA to register multiple times over different connections or flows and the proxies can use the instance-id in the contact header to identify that the multiple flows go to the same UA. It can then choose which flow to use to route requests to this UA.


Cullen Fluffy Jennings
Alan Hawrylyshen

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