Media Gateway Controller
Encyclopedia
A Media Gateway Controller (MGC) is a system used in certain Voice over IP
telephony architectures. An MGC controls a number of dumb terminals, the Media Gateway
s. The MGC receives signalling information (like dialed digits) from the Media Gateway and can instruct it to alert the called party, to send and receive voice data etc.
There are several protocols which can be used between MGC and Media Gateway: SGCP
, IPDC
, MGCP and Megaco
(also known as H.248).
The MGC receives also the term Call Agent when referred in the context of MGCP.
Some MGCs can interface with other signalling protocols, like SS7
(for interconnection with the traditional telephone system), H.323
and SIP
.
A VoIP architecture using an MGC is sometimes called a softswitch
architecture. Advantages of a softswitch architecture are that the Media Gateways are easy to maintain and that the softswitch operator retains full control. On the downside, softswitch architectures tend to be inflexible. Highly available MGCs are expensive to implement, as an MGC needs to be stateful.
telephony architectures. An MGC controls a number of dumb terminals, the Media Gateway
Media gateway
A Media gateway is a translation device or service that converts digital media streams between disparate telecommunications networks such as PSTN, SS7, Next Generation Networks or PBX...
s. The MGC receives signalling information (like dialed digits) from the Media Gateway and can instruct it to alert the called party, to send and receive voice data etc.
There are several protocols which can be used between MGC and Media Gateway: SGCP
Simple Gateway Control Protocol
Simple Gateway Control Protocol is a communications protocol used within a Voice over Internet Protocol system. It has been superseded by MGCP, an implementation of the Media Gateway Control Protocol architecture....
, IPDC
Internet Protocol Device Control
Internet Protocol Device Control is a specification for controlling hardware devices, developed by Level 3 Communications and a group of other telcos. Protocol was designed for communicating between centralized switches and IP-based gateways...
, MGCP and Megaco
Megaco
Megaco is a gateway control protocol. and an implementation of the Media Gateway Control Protocol architecture for controlling media gateways in Internet Protocol networks and the public switched telephone network...
(also known as H.248).
The MGC receives also the term Call Agent when referred in the context of MGCP.
Some MGCs can interface with other signalling protocols, like SS7
SS7
SS-7 can stand for:* Signaling System #7, a set of telephone signaling protocols.* The R-16 missile, with NATO reporting name SS-7 Saddler.* China Railways SS7, an electric locomotive model in China.* Super Socket 7, a chip socket introduced by AMD...
(for interconnection with the traditional telephone system), H.323
H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector that defines the protocols to provide audio-visual communication sessions on any packet network...
and SIP
Session Initiation Protocol
The Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...
.
A VoIP architecture using an MGC is sometimes called a softswitch
Softswitch
A softswitch is a central device in a telecommunications network which connects telephone calls from one phone line to another, typically via the internet, entirely by means of software running on a general-purpose computer system...
architecture. Advantages of a softswitch architecture are that the Media Gateways are easy to maintain and that the softswitch operator retains full control. On the downside, softswitch architectures tend to be inflexible. Highly available MGCs are expensive to implement, as an MGC needs to be stateful.
See also
- H.248 Information Site This site provides information related to H.248, including pointers to standards and draft specifications