Media gateway control protocol architecture

Media Gateway Control Protocol Architecture defines the protocol requirements for the Media Gateway Control Protocol between a Media Gateway Controller and a Media Gateway. The architecture and requirements are defined .

A gateway is a device that offers an IP interface on one side and some sort of legacy telephone interface on the other side. The legacy telephone interface may be complex, such as an interface to a legacy PSTN switch, or may be a simple interface that allows one to connect one or a few traditional telephones. Depending on the size and purpose of the gateway, it may allow IP-originated calls to terminate to the PSTN (and vice-versa) or may simply provide a means for a person to connect a telephone to the Internet.

Originally, gateways were viewed as monolithic devices that had call control (H.323/SIP) and hardware required to control the PSTN interface. In 1998, the idea of splitting the gateway into two logical parts was proposed: one part, which contains the call control logic, is called the Media Gateway Controller(MGC) or call agent (CA), and the other part, which interfaces with the PSTN, is called the Media Gateway(MG). With this functional split, a new interface existed (going between the MGC and MG), driving the necessity to define Media Gateway Control Protocol Architecture and Requirement.

Protocols

Two widely implementation of Media Gateway Control Protocol Architecture are H.248/Megaco and Media Gateway Control Protocol (MGCP).

Currently H.248 is published International Telecommunication Union (Recommendation H.248.1). The ITU has published three versions of H.248.1. Media Gateway Control Protocol (MGCP) is defined Internet Engineering Task Force (RFC 3525)

Both H.248 and MGCP are protocol for controlling Media Gateways from Media Gateway Controller or called Call Agents. In a VoIP system, H.248 and MGCP are used with SIP or H.323. SIP or H.323 will provide the call control functionality and MGCP can be used to manage media establishment in media gateways.

RFCs

• RFC 2805 - Media Gateway Control Protocol Architecture and Requirements
• RFC 3435 - Media Gateway Control Protocol (MGCP) Version 1.0 (this supersedes RFC 2705)

See also

• H.248
• Media Gateway Control Protocol
• Session Initiation Protocol (SIP)
• RTP audio video profile
• Voice over Internet Protocol

External links

• MGCP Information Site Information related to MGCP
• H.248 Information Site Information related to H.248/Megaco, including pointers to standards and draft specifications
• ITU-T H-series Recommendations ITU-T Publication site where the H-series, including the H.248 Sub-series, Recommendations can be downloaded in PDF format free of charge.
• H.248.1.