The session initiation protocol (SIP) is the multi-media network control protocol,designed to provide basic call control and to establish,modify and terminate multimedia (voice,data,video and so on)sessions and so on,in a packet-switched network.

• SIP协议是多媒体通信网的控制协议,在分组交换网中,它提供基本的呼叫控制,负责建立、修改和终止多媒体(话音、数据、视频等)会话等应用。