Используемые протоколы связи

SIP (Session Initiation Protocol, RFC 3261)
SDP (Session Description Protocol, RFC 3264, RFC 4566) WIKI
RTP (Real-time Transport Protocol, RFC 1889, RFC 3550) WIKI
RTCP (Real-Time Transport Control Protocol, RFC 3550) WIKI
STUN (Session Traversal Utilities for NAT, RFC3489, RFC 5389) WIKI
TURN (Traversal Using Relay NAT, RFC 5766) WIKI
SCTP (Stream Control Transmission Protocol)