SIP API (JSR-180)
The SIP API is used by the applications to implement SIP User Agent (UA) functionality. The following picture shows what interfaces terminals A and B are using to implement SIP User Agent Client (UAC) and User Agent Server (UAS) functionality respectively.
SIP (Session Initiation Protocol) Overview
SIP is an application-layer control protocol that can establish, modify, and terminate multimedia sessions. SIP can also invite participants to already existing sessions. SIP transparently supports name mapping and redirection services, which supports personal mobility - users can maintain a single externally visible identifier regardless of their network location (see RFC 3261 ). SIP can also be used to implement non-real-time services like Instant Messaging and Presence .
SIP supports five facets of establishing and terminating multimedia communications:
-determination of the end system to be used for communication
-determination of the willingness of the called party to engage in communications
-determination of the media and media parameters to be used
- establishment of session
- including transfer and termination of sessions, modifying session parameters, and invoking services