SIP (Session Initiation Protocol)

An IETF defined protocol (RFC3261) that defines an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences. Used as the call signaling protocol in VoIP, i2 and i3.

NENA-STA-010, Detailed Functional and Interface Standards for the NENA i3 Solution