The Session Initiation Protocol (SIP) is the IETF basis used for the creation of multimedia sessions. The sessions may be utilized for video, audio, instant-messaging amongst many other real-time based data communication sessions.

Constructing a whole setup which uses the SIP protocol needs the creator to understand the base SIP specification & a whole host of protocol documents which are aimed for a specific application. For instance, SIP (Session Initiation Protocol) is defined separately from the SIP specification for Instant Messaging plus when SIP is used with VoIP (Voice Over IP) the individual setting it up needs to have a grasp of SDP (Session Description Protocol) and that is a completely separate RFC. The SIP protocol being ‘modular’ in this way is seen as a strength.

SIP (Session Initiation Protocol) has a relatively broad scope which includes the ability of pretty much any variety of session connecting two individuals. SIP is as well totally free from the core vehicle, however, TCP (Transmission Control Protocol) & UDP (User Datagram Protocol) are utilized practically solely.

SIP was originally available as an Internet Draft from the IETF during 1996, and the primary RFC was in 1999.