SIP protocol

The emergence of telephony services, and more broadly interpersonal multimedia communications over IP networks, has led to the need to define a protocol dedicated to call signaling. This protocol, named SIP (Session Initiation Protocol), is standardized by the Internet Engineering Task Force (IETF) through Request for Comments RFC 2543.

As part of the general multimedia communication scheme proposed by the IETF, the SIP protocol competes with the signaling mechanisms implemented in H.323 systems (see the "Internet telephony" article in this treatise).