Sofia-SIP is an open-source SIP User-Agent library, compliant
with the IETF RFC3261 specification. It can be used as
a building block for SIP client software for uses such as VoIP,
IM, and many other real-time and person-to-person communication
services. The primary target platform for Sofia-SIP is
GNU/Linux. Sofia-SIP is based on a SIP stack developed at
the Nokia Research Center.
