SIP – Session Initiation Protocol

SIP (Session Initiation Protocol) is the IETF's (Internet Engineering Task Force) standard protocol for VoIP. This is the Internet standard for VoIP applications. It uses message formats similar to that used by the world wide web protocol (HTTP) to initiate sessions (make calls). SIP uses RTP for the transmission of voice. Currently SIP is the most popular VoIP protocol in terms of support if not in terms of numbers of users.

For more information on SIP use the following links:

• RFC 3261, SIP: Session Initiation Protocol

• Sip Centre