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.
