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The following texts were recently approved by ITU-T Study Group 11:
Additional Information on the H.248 sub-series relevant to TDR/EW
H.248 natively supports a number of functions that may be useful in a system that supports elements of EWS. As H.248 can be used between MGCs and MGs that use different call control protocols (e.g. ISUP, BICC, SIP, H.323) and different bearer technologies (e.g. IP, ATM, TDM) it may be an important link between services defined at a call level and the actual bearers.
Some functions that may be relevant are: H.248.1 supports the ability for a Media Gateway Controller (Call Server) to order announcements to be sent to all subscribers (or combination of subsets of subscribers) connected to a media gateway. The ability to send announcements is defined H.248.7 & H.248.9. This effectively allows a broadcast to a large number of users. However one must keep in mind that media gateways have a finite set of resources, so these must be managed so as to avoid introducing an overload situation.
H.248.1 supports the ability to prioritise resources handling to different types of calls. Through the use of context attributes it is possible to request preferential handling of calls based on the International Emergency Preference Scheme (IEPS), Emergency Call or one of 16 levels.
H.248.1 supports mechanisms to handle cases of media gateway overload in H.248.10 and H.248.11. It has also recently added a mechanism to prevent Media Controller overload in H.248.1v3.
Summary of ITU-T Study Groups with security-related activitieshttp://1f8a81b9b0707b63-19211.webchannel-proxy.scarabresearch.com/ITU-T/worksem/security/200510/sginfo_sec
Handbook "Deployment of IMT-2000 Systems" (2002)http://1f8a81b9b0707b63-19211.webchannel-proxy.scarabresearch.com/ITU-D/imt-2000/documents/IMT-2000_Handbook_Web_1.pdf