Libre is a portable and generic library for real-time communications
with async IO support and a complete SIP stack with support for SDP,
RTP/RTCP, STUN/TURN/ICE, BFCP and DNS Client.

Features:

- SIP Stack (RFC 3261)
- SDP
- RTP and RTCP
- DNS-Client
- STUN/TURN/ICE
- BFCP
- Jitter-buffer
- Async I/O (poll, epoll, select)
- UDP/TCP/TLS transport

WWW: http://www.creytiv.com/re.html