A lot can be said about SIP, and if you read the IMTC blog – You probably know it already.
SIP is a signaling protocol used for controlling multimedia sessions – Video calls, Voice calls, Presence information/IM etc. It’s an application layer protocol, and is in depended of the transport layer – TCP/UDP/SCTP.
SIP is IETF-defined and accepted in 2000 as a signaling protocol for 3GPP, becoming a part of the IMS (IP Multimedia Subsystem) architecture.
SIP is widely used in all sort of multimedia devices – it is indeed, the de-facto standard of IP communication solutions. It’s a key in unified communications and is mostly popular in the VoIP community.
The protocol is highly interoperable but lacks dedicated definitions for IP Video Call Control – IMTC SIP Parity AG helps developing common practices and use cases to improve its interoperability.
SIP Center – http://www.sipcenter.com/sip.nsf/index
Wikipedia Entry – http://en.wikipedia.org/wiki/Session_Initiation_Protocol
