Introduction - If you have any usage issues, please Google them yourself
" Session Initiation Protocol (Session Initiation Protocol-SIP) is an application layer control protocol signaling. To create, modify, and terminate one or more participants in the session. These sessions can be Internet multimedia conferencing, IP phones or multimedia distribution (example: voice mail). multicast session by the participants (multicast), mesh unicast (unicast) or a mixture of the two to communicate. "