Media Gateway Control Protocol (MGCP) is used for controlling telephony gateways from external call control elements called media gateway controllers or call agents. A telephony gateway is a network element that provides connectivity and conversion between different types of networks such as the audio signals carried on telephone circuits and data packets carried over the Internet or over other packet networks.
MGCP assumes a call control architecture where the call control intelligence is outside the gateways and handled by external call control elements. The MGCP assumes that these call control elements, or Call Agents, will synchronize with each other to send coherent commands to the gateways under their control. MGCP is, in essence, a master/slave protocol, where the gateways are expected to execute commands sent by the Call Agents.
The MGCP implements the media gateway control interface as a set of transactions. The transactions are composed of a command and a mandatory response. MGCP forms the basis of the PacketCable NCS protocol.
