The main purpose of SIP is to initiate and terminate interactive multimedia sessions, such as voice, video and chat. One of the most attractive features of SIP is the redirect, which makes it possible it for users to initiate and receive communication and services from any location, and for networks to identify the users where ever they are. SIP are not limited to any particular type of communication but can mediate any kind of communication session.
SIP was developed by the Internet Engineering Task Force (IETF) and was selected by 3GPP as a standard for IP Multimedia (IMS) in Release 5.
