IRR Fields

Lior Moscovici Lior_Moscovici at VOCALTEC.COM
Tue Sep 9 12:31:27 EDT 1997


Your observation leads to the general question that whether it is necessary to
support the opening of a media channel during the Q931 call signaling
procedure. This concerns other scenario as well. For example, when an H323
endpoint calls a POTS user via a gateway, while the Q931 call signaling is
in progress it may be required to have a voice channel opened between the
endpoint and gatweay to forward a PSTN special announcement ("sorry, the number
you dialed is not in service") back to the endpoint. As I remebered, a
while ago there was a decision made from this subject group about h323
implementation, that no capability exchange will take place before the
Q931 signaling is completed. I am not sure about the rational behind it,
but maybe that can be brought up again for discussion.

I looked at APC-1280 and found no descriptions for the procedure of using
the Progress-UUIE which is proposed to solve the above-mentioned problem.
Will this be added later on?

Ben Tang
Lucent Technologies
btang at

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