sofia-sip-1.12.4，NOKIA研发中心开发的SIP协议栈，可以跨平台编译运行，可以在Symbian操作系统下运行。

Sofia-SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification (see the feature table). 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-pe