A Formal Model for Media Negotiation between SIP User Agents
Telecom Italia
Telecom Italia
This document provides a formal description of the interactions between two SIP User Agents establishing a multimedia session, describing the negotiation of the two parties as an exchange of signals between two instances of networks of Finite State Machines (FSMs). The goal is to provide a common reference model for both SIP extensions and User Agent implementations: two flows that can be implemented by using the external interface of the FSMs are guaranteed not to conflict to each other. On the other hand a reference model for User Agents is expected to improve interoperability between different implementations and help implementors to model their software in a way that makes SIP extensions conforming to this document easier to implement.