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

Kamailio is a GPL licensed SIP server implementation. It started in 2005 as a fork of Fokus Fraunhofer SIP Express Router (SER) project. Kamailio wants to be a more open project, not only from license point of view, but more open as project managemen