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A Single Router Channel Causing PBX to Seize All Channels?

A Single Router Channel Causing PBX to Seize All Channels?

A Single Router Channel Causing PBX to Seize All Channels?

I'm research a problem.
I'll start by saying I'm not a Cisco enginner, I'm a PBX engineer.
I do not have access to complete show runs, I've only been given snippets.

Here is the issue:
Our PBX is connected to two different routers (3925 & 3945) via T1s programmed ESF B8ZS, E&M Immediate Start.
There is never any slips or framing losses.

Here's a sample snippet of channel config:
voice-port 3/0:1
define Tx-bits idle 1111
define Tx-bits seize 0000
define Rx-bits idle 1111
define Rx-bits seize 0000
connection plar xxx

There are 5 T1s connected to *two* different PBXs in the same rack.
On one T1, if the 1st channel is active (meaning not in shutdown mode and programmed as PLAR) on the Cisco side, when the PBX initiates a call on any other channel it will sieze *ALL* channels outbound. I'd be willing to say that we have bad hardware or even software but the problem with that theory is the problem follows the T1 to known good working T1 ports and even on the other PBX.

If I put a T-Berd (facing either the Cisco or the PBX) in terminate mode and generate traffic outbound to it I can't duplicate it. If I loop the T1 back to itself I can't duplicate it. The only time I can duplicate it is when I'm connected to that single T1 on the Cisco.

The PBX itself does not show these seizures. There are no software logs of any type from the PBX generated to support showing that it is seizing all the channels. However every tool we have in our arsenal shows this to be the case.

The T1 on the Cisco has been moved to a different port and even to a different router. No change.

Can anyone think of anything that could possibly be generated on a single channel that could cause a remote system to become flaky on all the other channels? The only thing I could come up with myself is perhaps DB level and perhaps that may cause some type of "distortion". But I'm told it's set to 0 (zero).

A bit of history:
This all actually started on a different T1. Through normal outbound usage, about 10 times a day the system would seize all trunks. Again, never any slips or framing losses. Through the trouble shooting process it was decided to move one of the PLARs to an unused channel on a T1 that wasn't having any issues. The problem then followed to the second T1 (The one mentioned above). It was then decide to move that channel back however the problem remained on the second T1.

Extreamly frustrating to be sure.

And another really quick question.
I'm told this would represent channel 24 on the T1 0/0/2:0 and that channel 1 is 0/0/2:1 - Is that correct?

Dry Aquaman


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