SIP is designed as part

SIP is designed as part of the overall IETF multimedia data and

control architecture currently incorporating protocols such as RSVP

(RFC 2205 [2]) for reserving network resources, the real-time

transport protocol (RTP) (RFC 1889 [3]) for transporting real-time

data and providing QOS feedback, the real-time streaming protocol

(RTSP) (RFC 2326 [4]) for controlling delivery of streaming media,

the session announcement protocol (SAP) [5] for advertising

multimedia sessions via multicast and the session description

protocol (SDP) (RFC 2327 [6]) for describing multimedia sessions.

However, the functionality and operation of SIP does not depend on

any of these protocols.