Private Session Initiation Protocol (SIP) Extensions for Media Authorization

This document describes the need for Quality of Service (QoS) and media authorization and defines a Session Initiation Protocol (SIP) extension that can be used to integrate QoS admission control with call signaling and help guard against denial of service attacks. The use of this extension is only applicable in administrative domains, or among federations of administrative domains with previously agreed-upon policies, where both the SIP proxy authorizing the QoS, and the policy control of the underlying network providing the QoS, belong to that administrative domain or federation of domains.