VWIC-2MFT-T1-DI to Avaya G3 PBX

Unanswered Question
Apr 11th, 2008

Greetings all,

I am having an issue with 12 voice channels on a DS1 going to an Avaya PBX using the VWIC-2MFT-T1-DI in a 2821. It works for a while then the trunk goes to out-of-service on the PBX side after many hours of use. I have to busy out the trunk to get the trunk to idle/in-service . It works fine using a Larscom CSU. Here are relevant parts of the config:

network-clock-participate wic 0

network-clock-select 1 T1 0/0/0

controller T1 0/0/0

framing esf

linecode b8zs

channel-group 0 timeslots 1-12

tdm-group 1 timeslots 13-24 type e&m

description "768kb"


controller T1 0/0/1

framing esf

clock source internal

linecode b8zs

tdm-group 1 timeslots 13-24 type e&m

description "PBX 768kb"

connect LINE-to-PBX T1 0/0/0 1 T1 0/0/1 1

I am getting a small amount of path code violations on the 0/0/0 side and Slips and Errored Seconds on the 0/0/1 side.

I suspsect clocking is the source of the issue, but I cannot figure out why it works when I swap to the Larscom CSU. Any input would be appreciated.


I have this problem too.
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garycook411 Fri, 04/11/2008 - 11:38


I am using release:

Cisco IOS Software, 2800 Software (C2800NM-SPSERVICESK9-M), Version 12.4(15)T3,

RELEASE SOFTWARE (fc1). Let me know if I can provide any other information that can be useful.


Paolo Bevilacqua Fri, 04/11/2008 - 12:03

IOS should not be an issue. Your clocking config is correct. I would suggest:

1. check cabling, proper T1 cable 100 Ohm twisted 1-2 4-5, no other wires connected. Greatest would be shielded cable.

2. under controller T1, configure cablelenght short 133 (I assume that is what you have).

The idea is to eliminate all an any error on both controllers. The PBX might bee seeing too many and shutting down port because of that.

garycook411 Fri, 04/11/2008 - 12:41

Thanks for the input. I have cablelength short 133. I have tried different cables. Right now I can swap back to a Larscom CSU and the trunks instantly go in-service/idle. This is definitely a frustrating one.

Thanks much!

Paolo Bevilacqua Fri, 04/11/2008 - 13:01

Are you seeing any error on se0/0/0:0 ? That would indicate the problem generates from the telco side and somewhat propagates to PBX.

garycook411 Fri, 04/11/2008 - 13:09

Ser 0/0/0:0 is running clean. When I hook up the CSU it looks perfect also. No Frame Errors, no alarms or events, just clean stats.

The data side has been running great.

Currently, we are having trouble getting all the channels on the trunk to come up at all with the WIC. It seems to have got a bit worse. It almost seems like the WIC is not passing clocking properly but, it looks good on the cisco side:

#show network-clocks

Network Clock Configuration


Priority Clock Source Clock State Clock Type

1 T1 0/0/0 GOOD T1

10 Backplane GOOD PLL

Current Primary Clock Source


Priority Clock Source Clock State Clock Type

1 T1 0/0/0 GOOD T1

Thanks much!

Paolo Bevilacqua Fri, 04/11/2008 - 13:29

Strange really. Do you have the router under maintenance ? The tac can replace the vwic or perhaps send a vwic2 that is more advanced on clocks. You can also try downgrading to 12.4(3j) but that is more shooting in the dark.

garycook411 Mon, 04/14/2008 - 08:17

That is what I figured I would have to do. I opened a TAC case this morning. The VWIC2 might just be the answer. I will let TAC figure it out. Thanks for the suggestions!


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