The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol distributed by IETF for creating, modifying, and terminating sessions with one or more participants.

• 会话启动协议)是由IETF提出的一个应用层的信令控制协议，用来创建、修改和终结一个或多个参加者参加的会话进程。