In communications systems, through consultations, so there must be a corresponding agreement. In NGN architecture softswitch is a control center, which support H.248/MeGaCo and SIP, MGCP, H.323 and other scale agreement.
1 MGCP Protocol
1.1 MGCP basic concepts
SIP and MGCP protocols with the H.223 different H.323 and SIP provides two IP phone architecture, two completely independent, may not be compatible with, and can only Exchange. MGCP does not involve IP telephone architecture involved only the gateway decomposition, thus not only used in H.323 IP telephone system, can also be used for SIP IP phone system. Gateways can be broken down into a media gateway (MG) and a media gateway controller (MGC), MG MGC (softswitch) under the control of media across network. From a logical point of view is very simple, consisting of gateway by the MG and MGC. From a physical point of view is not so simple, and so far, the decomposition of the gateway has not been decided, can be decomposed according to different requirements.
MGCP Protocol is in 1999 by the Internet Engineering Task Force (IETF) developed by Media Gateway Control Protocol MGCP Protocol defines connectivity models including endpoint (endpoint) and connection (connection), two key concepts. Endpoints are data sources or data, which can be a physical endpoint, or a virtual endpoint. Endpoint types include digital channel, analog line, recording servers and by the interactive voice response access points. Endpoint identified by the endpoint where the gateway domain name and gateway's local name is composed of two parts. Connections can be point-to-point or multipoint connections. Point-to-point connections between two endpoints that send data to each other is an association, at the two ends of the Association are established, you can start data transfer. Multi-point connections between multiple endpoints. Connections can be built in different types of hosts on the network. Call Agent may request the endpoint detects certain events (such as plucking machine, hanging, Hooking, or dial-up) occurs, to issue a notice may also request certain signals (such as dial tone, ring back tone, busy tone, etc) added to the endpoint. Events and signals into packets, each packet is supported by a particular endpoint. Each event (signaling) available "package name/event name", each vertex has a particular package, each packet contains a regular event and signal, the package name and the event name using alphanumeric string.