CUCM 7.1(3a) Ad-hoc conference: Busy Tone after one member leaves

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Dec 14th, 2009
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In an ad-hoc conference if one external member leaves, the remaining members are hearing a busy tone.

We are using CUCM 7.1(3a) and a 2821 router as the H.323 gateway to PSTN.

This gateway is also the conferencing bridge.

In this context I notice when at the end of an external call TO an IP phone the external party hang up the call releases immediately after the DISCONNECT signal.

At the end of an external call FROM an IP phone the IP phone user gets a busy tone when the external party hang up. The RELEASE signal occures 40 seconds later after receiving the DISCONNECT signal.

Are there any configuration tasks in CUCM and/or gateway to change this behavior, so that at "normal call clearing" the call will be released in any case.

For your information:

I issued the voice call convert-discpi-to-prog command as described here because we don't hear the announcement if the called party number is out of order.

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parshah Mon, 12/14/2009 - 16:20
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Please correct me if I am wrong.

You have a 3 party audio conference. 2 internal parties using IP Phones and 1 external party calling over PSTN. One of the internal user initiated the 3 party conference. This uses the hardware conference bridge on 2821. Now at the end if/when the PSTN user disconnects, the 2 internal IP Phone users disconnect as well. Am I correct?

If so, can you tell me what audio codec each user negotiates when the 3 parties are in conference? Also, what is the model of the internal IP phones in this test.

Can you please attache the conference bridge config from the router. A show run would do.


holger.hahn Tue, 12/15/2009 - 00:22
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sorry but you are wrong.

When the PSTN user disconnect the conference fore the two remainig internal users still exist but they hear a busy tone.

The call for the PSTN user won't be released. In q.931 debug you can see, that there is a DISCONNECT singnal but no RELEASE signal.

It's the same thing when an internal IP phone user initiate an external PSTN call. When the PSTN user disconnect the call htere is also only the DISCONNECT signal from PSTN.

If the internal user won't go onhook the call will be released until 40 seconds (don't know which timer is involved).

Is the call initiated by the PSTN user and disconnect by him then the call will be released immedialtely after receiving the DISCONNECT signal.


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