SIP Stacks libmsip: A C++ SIP stack for Linux developed for the miniSIP project. Homepage: http://www.minisip.org/libmsip/.

SIP Stacks dissipate2: C++ Linux, requries the qt-library, License: GPL Homepage: http://www.wirlab.net/kphone/ A enhanced dissipate, is part of the kphone distribution.

SIP Stacks GNU eXosip: C Linux+Windows+... License: GPL Homepage: http://savannah.nongnu.org/projects/exosip/ The extensible osip: \"...It aims to implement a simple high layer API to control the SIP for sessions establishements and common extensio

SIP Stacks SIP from vovida.org: C++ Linux+Windows+... License: Vovida Software License Homepage: http://www.vovida.org/protocols/downloads/sip/