Subject: I-D ACTION:draft-ietf-sip-183-00.txt

From: [email-masked]
Date: Tue, 26 Oct 1999 07:25:31 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Session Initiation Protocol Working Group of the IETF.

	Title		: SIP 183 Session Progress Message
	Author(s)	: S. Donovan, H. Schulzrinne, J. Rosenberg,
                          M. Cannon, A. Roach
	Filename	: draft-ietf-sip-183-00.txt
	Pages		: 26
	Date		: 22-Oct-99
	
This document describes a proposed extension to SIP [1].  This exten-
sion adds the 183 Session Progress response and a new header to indi-
cate why a SDP message body is included in a 18x message.
The introduction of the 183 informational response message would
allow a called user agent to indicate to the calling user agent
whether or not the calling user agent should apply local alerting for
the session.  The existing 180 Ringing message would indicate that
the calling user agent has the option of providing local alerting
(and generally should).  The 183 Session Progress message would indi-
cate that the calling user agent should not provide local alerting.
In additionally, the calling user agent may be called on to establish
a media session to be used by the called user agent to indicate the
status of the session setup request as part of the indicated media
stream.  The indication of whether or not to play early media to the
calling user would be controlled with a new Session header included
in the 183 message.

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