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New Member

Dropped calls on call manager 7 be


I have a customer that has been having issues with dropped calls.

The site uses h323 protocol and dial peers to push calls to either analog trunks or t1.

So far calls are being dropped to mostly cell phones during a conversation

have anyone have this issue, the provider has said that the issue is not related to them.

New Member

Re: Dropped calls on call manager 7 be

As a matter of fact, I've had very similar issues today on UCMBE 7.1.5. I've had the system in place for two and a half weeks, and this just started today with outbound calls having a lot of static on them and then inevitably drop after a few minutes. However, inbound calls over the same PRI circuits are fine and are not dropped. I have opened a TAC service request in order to troubleshoot if it's something on my end or a PRI issue.

New Member

Re: Dropped calls on call manager 7 be

I got off the phone with TAC and got some information that we were having slips and errors on our PRI circuits. I don't know your level of familiarity with the gateway devices, but I will give you the commands I was able to learn in order to help diagnose our issue and maybe they will help you...

First, they had me telnet/ssh to my gateway router, in my case a 2821 router. From there I logged in and ran the following:

show controllers t1

>> This showed the statistics on my PRI channels which revealed the slips and errors we were experiencing.

Afterwards, we ran:

show network-clocks

>> This showed the order and status of my PRI's network clock to verify they were in proper sync with the circuits.

They looked good for us, but it did reveal that only one of my PRI's was actually being utilized. (Network-clock-select 1 t1 0/0/0), so we enable and go to configure terminal which allowed us to add the second one:

network-clock-select 2 t1 0/0/1

>> This may vary depending on your setup, but essentially it allows your gateway to use that circuit.

From that point, we ran a clear counters from the main prompt and then issued the show controllers t1 command again to verify that the slips were either stopped or continuing. I'm continuing to monitor, but unfortunately it's after business hours, so I likely won't see any issues until tomorrow morning when business picks up again.

Now that said... the appearance of slips/errors on the controller ports is a sign of issues between you and the provider, but it could be anything from cabling issue to circuit issue or internal. For example, my not having the second PRI active may have caused load issues for us... or it could still be an AT&T issue. But, at least with this info it may help you narrow the issue down.

Hope it helps... good luck!

New Member

Re: Dropped calls on call manager 7 be

Thanks for your help

Unfortunately the smartnet expired for this customer so i cant open a TAC case to troubleshoot.

I will take note of the commands and advise on the output.

New Member

Re: Dropped calls on call manager 7 be



I got the logs for the T1 controller and there are some slips and errors however I am not sure why this is happening. Is there some debugs i can run to get some more info and move closer to resolving this issue.

New Member

Re: Dropped calls on call manager 7 be

Good question... I'm waiting for some feedback from TAC about my case, though I'm 99% certain it's an issue with AT&T.

For now, I've validated my own configurations by trying to follow through this guide:

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