The primary IP telephony signaling protocols are H.323, SIP and MGCP/MEGACO. There are also proprietary protocols; for example, Cisco's Skinny is widely used. See IP telephony. THIS DEFINITION IS ...

Network Call Signaling (NCS ... and are managed by the media gateway controller. Like SIP, MEGACO is a text-based protocol, unlike H.248, which is binary based. See H.323 and SIP.