Omission in H.245 v7

Rajesh Kumar rkumar at CISCO.COM
Wed Mar 28 21:55:40 EST 2001

Dear ITU SG16 team,
I just came across what I believe is an unintended omission in H.245 v7.

Although you have added support for rfc2833 to the 'terminal capability
set' command, you have not included it as one of the CHOICEs for the
dataType object in the Open Logical Channel command. The upshot is that you
cannot dynamically assign a payload type to rfc2833 telephone events in the
'fast connect' scenario where the 'terminal capability set' command is not
used. For all practical purposes, this means that you either statically
provision the rfc2833 capability, which the IETF has decried, or you do not
use Fast Connect when you support telephone events.

All indications are that this is a minor, unintended omission on the part
of SG16: nobody has discovered it as yet. It can be fixed easily. The Open
Logical Channel dataType object points to the capability objects anyway,
and there is no reason to omit AudioTelephonyEventCapability as an instance
of the dataType object.

How should we go about fixing this - H.245 is still in draft, although
there is preliminary approval of it?


Dr. Rajesh Kumar, Principal Engineer
Cisco Voice Technology Center
Tel: 408-527-0811, Fax: 408-853-1101
Epage: mailto:rkumar at

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