APC-1470 - IVR Requirements - on FTP site

Pete Cordell pete.cordell at BT-SYS.BT.CO.UK
Wed Nov 11 13:27:27 EST 1998

    Dear experts,

    There seems to be an ambiguity in H.323 / H.225.0 concerning alias
addresses exposed by a Gateway (not MC / MP) to a Gatekeeper.

The question is :
        What aliases is a Gateway to use during Gatekeeper-related messaging
    be able to appear as several H.323 terminals later ? May the alias
    used as sourceAddress during Discovery/Registration Requests and during
    Admission Request differ ?

H.323 Section 3.16 says :
    >> An H.323 Gateway (GW) is an endpoint
This inspires the idea of a Gateway having it's own aliases; but they CANNOT
a composition of a all possible E164 numbers.

H.225.0 Section 7.8.1 says :
    >> GRQ is sent per logical endpoint; thus ... a Gateway might send many.
Does that mean that a Gateway can be considered as a composition of
multiple logical Endpoins ? Then, should each of them use separate
Discovery/Registration process ?

    There are 3.5 possible ways to interpret this :

    a)     Gateway pretends to be a composition of multiple logical
            each of them use separate Discovery/Registration/Admission
            with different aliases
    b1)   Gateway's own unique aliases are used for GK
            process which happens only once, but when making a call,
            the sourceAddress field of AdmissionRequest is filled with
            appropriate SCN Terminal's E164 number
    b2)   Same as b1), but both Gateway's and SCN Terminal's aliases are
            for Admission Request.
    c)     Gateway always uses it's own unique aliases and
            does not tell the source E164 number to the Gatekeeper

    What is the common practice here ?
    Which way do existing GK / GW implementations act ?
    Please, answer, if you have ideas.

Thank you.

Alexander S. Rovny
MD Information Systems
rovny at mdis.ru

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