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Supporting Intermediary Session Policies in SIP

Document Type Replaced Internet-Draft (individual)
Expired & archived
Authors Jonathan Rosenberg , Volker Hilt
Last updated 2002-05-03
Replaced by draft-hilt-sipping-session-policy
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-hilt-sipping-session-policy
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This Internet-Draft is no longer active.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:


The Session Initiation Protocol (SIP) was designed to support establishment and maintenance of end-to-end sessions. Proxy servers provide call routing, authentication and authorization, mobility, and other signaling services that are independent of the session. Effectively, proxies provide signaling policy enforcement. However, numerous scenarios have arisen which require the involvement of proxies in some aspect of the session policy. SIP has no support for such capabilities, as the community has generally considering involvement of proxies in session details 'evil'. Practical implementations have therefore resorted to non-standard manipulation of SDP messages in order to enforce session policy. These implementations are fragile and frought with problems. In this document, we discuss a middle-ground approach which permits proxies limited involvement in session policy, but retains the robustness that derives from the current prohibition on SDP manipulation.


Jonathan Rosenberg
Volker Hilt

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