Subject: I-D ACTION:draft-rosenberg-sipping-session-policy-00.txt

From: [email-masked]
Date: Mon, 06 May 2002 07:25:28 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: Supporting Intermediary Session Policies in SIP
	Author(s)	: J. Rosenberg
	Filename	: draft-rosenberg-sipping-session-policy-00.txt
	Pages		: 29
	Date		: 03-May-02
	
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.

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