The SIP Voice Protocol is an application layer control protocol for establishing, changing, and terminating multimedia sessions. It is part of the IETF multimedia data and control architecture and draws heavily on the mature HTTP protocol. It is easy to extend and easy to implement, so it is very suitable for implementing Internet-based multimedia conferencing, IP telephony and other systems.
SIP is an abbreviation of Session Initialization Protocol; one of the multimedia communication system framework protocols developed by the IETF, which is used to create, modify, and terminate session sessions attended by one or more participants. These sessions include Internet multimedia conferencing, Internet telephony, distance education, and telemedicine. That is, all interactive two-way or multi-party multimedia communication activities on the Internet are collectively referred to as multimedia sessions.
It belongs to the application layer protocol in the TCP/IP five-layer model; it belongs to the Session layer protocol in the OSI seven-layer model.
SIP can not complete multimedia calls alone, and must be combined with other protocols to form a complete multimedia communication system, and cooperate with RTP/RTCP, SDP, MGCP, DNS and other protocols to complete the multimedia session process.
