The Advertisement/Proposal Model of Session Description

Document Type Expired Internet-Draft (individual)
Authors Jon Peterson  , Cullen Jennings 
Last updated 2011-03-14 (latest revision 2010-03-01)
Stream (None)
Expired & archived
plain text htmlized pdfized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
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This Internet-Draft is no longer active.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


In common SIP practice, a two-phase "offer/answer" exchange of session description documents negotiates preferences, capabilities and requested sessions. However, the structure of the session description greatly confuses the disambiguation of these elements and thus the clear characterization of sessions. The current work proposes an alternative to the offer/answer model which leverages pre-association between user agents to recast those two phases into a less ambiguous form: an Advertisement of capabilities and preferences which occurs in non-real-time before a session is ever requested, which is followed during session establishment by a unidirectional and complete Proposal of a session.


Jon Peterson (
Cullen Jennings (

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