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Question 3/16

Question 3/16 - Multimedia gateway control architectures and protocols

(Continuation of Question 3/16)


ITU T Study Group 16 created the H.248-series, which decomposed the H.323 gateway function defined in ITU T H.246 into functional subcomponents called media gateway controllers and media gateways and specified the protocols these components use to communicate. This enabled ITU-T H.323 gateways to be composed of components from multiple vendors distributed across multiple physical platforms. This work was done in collaboration with the now closed IETF Megaco Working Group. The H.248 protocol is applicable to many different types of gateways. H.248 can be used with media gateway controllers terminating a number of call/session control protocols, for example: BICC (which supports multimedia according to ITU T H.320), ISUP, SIP, H.323 and Q.931. H.248 can be used to control media gateways terminating TDM, IP, ATM and AAL2. H.248 has also found application in mobile 3G networks, IP-Cablecom networks and to control IP Phones. H.248 is an important element in today's softswitch architectures and networks. The ongoing penetration of IP at core network level and all kind of access network technologies draws the attention of IP-to-IP connection models (of ITU-T H.248 gateways) more and more into foreground.

Study items

This Question considers multimedia gateway architecture and the development of multimedia gateway control protocols for gateways interworking existing networks and new networks as defined by the next-generation network and IPTV groups. Specific study items include the addition of new functionality to the H.248.x sub-series to enable existing and new network nodes to work as a split media gateway controller and media gateway. Items of study may also include further work on IP-IP connection models such: QoS control, network address translation (NAT) and firewalling, enhanced conferencing, media streaming control and network access control. New functionality may be required for emerging telepresence architectures and protocols and to support gateways to new real time communication architectures from the IETF such as defined in the RTCWEB working group.

Considerations will be given on how to help mitigate climate change.


Tasks include, but are not limited to: An up-to-date status of work under this Question is found in the SG 16 work programme (