Media gateway - Definition and Overview

A Media Gateway acts as a translation unit between disparate telecommunications networks such as PSTN; Next Generation Networks; 2G, 2.5G and 3G radio access networks or PBX. Media Gateways enable multimedia communications across Next Generation Networks over multiple transport protocols such as ATM and IP.

Media Gateways are controlled by a Call Agent which provides the call control and signaling functionality. Communication between Media Gateways and Call Agents is achieved by means of protocols such as MGCP or Megaco.

VoIP Media Gateways perform the conversion between TDM voice to Voice over IP.

Mobile access Media Gateways connect the radio access networks of a public land mobile network PLMN to a Next Generation Core Network. 3GPP standards define the functionality of CS-MGW and IMS-MGW for UTRAN and GERAN based PLMNs.