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. Sofia SIP is
licensed under the LGPL.
