FXO calls drop after 10min

Unanswered Question
Jul 26th, 2009
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the scenario is

IP Phone - CM4.2 - H323 - VG - FXO - PSTN. after 10min outgoing calls generate echo and then the call drop. it happens arbitrarily.did anyone face this issue.


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pcameron Mon, 07/27/2009 - 00:23
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the most common reason why calls fail after the magical 10 minutes is there is a TCP keepalive timeout, and this then kills the H323 session. Chances are you have some kind of firewall of something else that is blocking the traffic.

We had several incidents of this being caused by customers putting 'Trend Micro Personal firewall' on the CUCM servers.

Another way to confirm this is a timeout issue is to change from H323 to SIP. These calls use UDP based transport, so there is no need for a layer 4 keepalive.

Eldho E Kuriakose Mon, 07/27/2009 - 01:01
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try changing gateway ios

once i was having this regorous issue with mgcp and it was a bug of mgcp protocol....

u can try that also....

mohdashraq Mon, 07/27/2009 - 01:07
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I tried earlier, but this didn't solve the problem.

mohdashraq Sat, 08/01/2009 - 23:31
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but I am using Call Manager version 4.2 so I can't use SIP neither MGCP because it doesn't support Caller-ID feature, I have Cisco ASA between the Voice router and the LAN: IPPhone - CCM - ASA - VG.

the problem is that this doesn't happen constantly. appreciate if you have some hints.

paolo bevilacqua Sun, 08/02/2009 - 03:11
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Do you have anything between router and CM ?

paolo bevilacqua Mon, 08/03/2009 - 08:55
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You should remove the ASA from the path, as indicated to you above.


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