Video experts: Proposal to add video to Desired/SupportedProtocols

24 Oct 2000


      Hi all,
I would like some feedback from the video experts for a contribution I wish to
make to expand SupportedProtocols, which has recently been added for use in
ARQ, LRQ,  SETUP, and Annex G Access Request messages. (ref: D-347 of 0200_Gen)
"desiredProtocols - Identifies the type of protocols, in order of preference,
the originating endpoint desires for its call (e.g., voice or fax).  A
resolving entity may use this field to locate an endpoint that also supports
the protocol, giving consideration to the order of preference."
Correct me if I'm wrong, but it seems that the objective of this addition, as
documented in D-347 is not fully achieved, since video capabilities cannot be
expressed. (it also strikes me that *protocols* may not be the best description
of the capabilities being negotiated here.)
If we were to complete the proposal, the change would probably look as below.
My specific question to the video experts: What should the VideoCaps structure
contain and how would it be used (clearly we do not intend to replace H.245
here). Thus, is there any good reason to conform to the structure of VoiceCaps -
 including the location of the '...' and the inclusion of 'SupportedPrefixes' ?
(is it ever used ?)
SupportedProtocols ::= CHOICE
{
        nonStandardData         NonStandardParameter,
        h310                            H310Caps,
        h320                            H320Caps,
        h321                            H321Caps,
        h322                            H322Caps,
        h323                            H323Caps,
        h324                            H324Caps,
        voice                           VoiceCaps,
        t120-only                       T120OnlyCaps,
        ...,
        nonStandardProtocol             NonStandardProtocol,
        t38FaxAnnexbOnly                T38FaxAnnexbOnlyCaps
---BEGIN
        ,
        video                           VideoCaps
---END
}
VoiceCaps ::= SEQUENCE
{
        nonStandardData         NonStandardParameter OPTIONAL,
        ...,
        dataRatesSupported              SEQUENCE OF DataRate OPTIONAL,
        supportedPrefixes               SEQUENCE OF SupportedPrefix
}
---BEGIN
VideoCaps ::= SEQUENCE
{
        nonStandardData         NonStandardParameter OPTIONAL,
        ...,
        dataRatesSupported              SEQUENCE OF DataRate OPTIONAL,
        supportedPrefixes               SEQUENCE OF SupportedPrefix
}
---END
Boaz Michaely
Senior System Architect, Corporate
Comverse Network Systems
Tel: +972 (3) 766-3844 , Mobile +972 (51) 62-58-44
mailto:boaz.michaely@ties.itu.int
http://people.itu.int/~michaely
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