Editing Media gateway (section)

{{More citations needed|date=April 2024}}[[File:Converged_Network_Architecture.png|thumb|right|400px| Media Gateways are used for transcoding media between  PSTN and IP networks]]
A '''media gateway''' is a translation device or service that converts [[streaming media|media streams]] between disparate telecommunications technologies such as [[Plain old telephone service|POTS]], [[Signaling System 7|SS7]], [[Next Generation Networks]] ([[2G]], [[2.5G]] and [[3G]] radio access networks) or [[private branch exchange]] (PBX) systems. Media gateways enable [[multimedia]] communications across packet networks using transport protocols such as [[Asynchronous Transfer Mode]] (ATM) and [[Internet Protocol]] (IP).

Because the media gateway connects different types of networks, one of its main functions is to convert between different transmission and coding techniques. Media streaming functions such as [[echo cancellation]], [[DTMF]], and tone sender are also located in the media gateway.<ref name=":0">{{Cite web |title=What is a Media Gateway? {{!}} Ribbon Communications |url=https://ribboncommunications.com/company/get-help/glossary/media-gateway |access-date=2024-04-23 |website=ribboncommunications.com |language=en}}</ref>

Media gateways are often controlled by a separate [[Media Gateway Controller]] which provides the call control and signaling functionality. Communication between media gateways and Call Agents is achieved by means of protocols such as [[Media Gateway Control Protocol|MGCP]] or [[Megaco]] (H.248) or [[Session Initiation Protocol]] (SIP). Modern media gateways used with SIP are often stand-alone units with their own call and signaling control integrated and can function as independent, intelligent SIP end-points.

[[Voice over Internet Protocol]] (VoIP) media gateways perform the conversion between [[Time-division multiplexing]] (TDM) voice to a media streaming protocol,<ref name=":0" /> such as the [[Real-time Transport Protocol]], (RTP), as well as a signaling protocol used in the VoIP system.

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 [[PLMN]]s.