ITU-T H.248.45 PDF

This Recommendation describes an extension to ITU-T Rec. H.248.1 [1] gateway control protocol to enable an MGC to store data on an MG that can be subsequently retrieved to facilitate MGC recovery action.

The standard H.248 audit mechanism permits an MGC to retrieve data from an associated MG in order to re-synchronize connection data/state between an MGC and an MG. In terms of identifying the other end of this bearer connection, the Remote Descriptor that is associated with the ephemeral termination enables the other end of the bearer connection to be identified – albeit not in a format that may be convenient for the MGC to use. In many cases, the Remote Descriptor may not enable the other end to be identified (e.g., some MGs may use different control and media addresses).

In order to achieve a coordinated recovery action, whereby both GW connections in a single call/end-to-end connection can be torn down in parallel, it is proposed to define this H.248 package to enable the MGC to store a block of data on an MG which enables the MGC to identify the other end of the bearer connection. The structure of the stored data is understood only by the MGC and is opaque to the MG. Thus, the MGC is now able, via standard H.248 audit mechanisms, to retrieve the previously stored data block in the event of an MGC failure. The MGC is now able to identify the other end of the connection (e.g., typically on separate MGs) and thus provide a coordinated clean-up of the related connections on the separate MGs. The MGC is at liberty to define the contents of the string in a proprietary manner that is most convenient for its own usage.