The Session Initiation Protocol (SIP)
Olivier Hersent · 2010
The session initiation protocol (SIP) was originally defined in RFC 2543 by the multiparty multimedia session control (MMUSIC) working group of the IETF. SIP now has its own working group within the IETF, which maintains close coordination with the MMUSIC group. This chapter describes the most common PSTN interworking scenarios, which work without extensions of SIP. It discusses the documented extensions of major SIP vendors. One of the applications that have emerged out of the multiple theoretical possibilities of the protocol is presence and instant messaging (IM). The adoption of SIP for IM by Microsoft made it a serious option, as an alternative to the only other open standard for IM : Jabber. Instant Messaging (IM), and more generally ‘Presence’ applications, is only the most popular applications of a more general use of SIP for the subscription and exchange of stateless event messages. Controlled Vocabulary Terms electronic messaging; message passing; multimedia communication; signalling protocols