Line Protocol Goes up and down.

[ddevecka]

I am having some issues with Line Protocol on one serial interface going up and down. I hope someone can help.

I have a VWIC-2MFT-T1 and EIGRP running. This is being used to allow 2 T-1's to load balance and be backups to one another. It has just started dropping the serial interface line protocol on 1 of the T's (for about 1 second every few minutes) causing our network to almost shut down. It had been working fine for about a month then just started doing this last week. I have replaced the router and VWIC just to make sure these aren’t the problem because we have had some power outages due to storms. Does this sound like a configuration problem or a T-1 problem? Another note is the VWIC (CSU/DSU) never gets an alarm. I am having the T-1 tested now.

Any help on this would be appreciated.

D

[Richard Burts]

If it has been working for a month and if you have not made config changes, then I think it is unlikely that your problem is a configuration problem.

When line protocol drops it indicates that there was a failure in keepalives. There are several things that may cause these symptoms. Probably the thing that I would look at first is the possibility that the serial interface is dropping enough packets that it is losing some keepalives and causing these symptoms. It might be helpful if you could clear the counter on the interface, let the interface run for a little while (through at least a few protocol down cycles) and then post the output of show interface. It might also be helpful to look at the interface on the router of the remote end and see how it looks.

HTH

Rick

[ddevecka]

Could the clock source be part of the issue? When I installed the new router I don't remeber configing that.

[Josef Oduwo]

Hello Dan,

Perhaps letting us have a copy of show controllers, show interfaces serial or the running configs could illuminate the problem.

Josef.

[Richard Burts]

My experience is that usually if there is a clocking problem you get a down interface not a flapping interface. But it would certainly be good to check on how clocking is configured on the new router as compared to the old router.

Also if the problem started on the old router and you replaced the router as an attempt to fix the problem then a missing parameter on the new router would not explain the problem on the original router.

As Josef says it would be helpful if you would post show inteface, show controller t1, and maybe the router config.

HTH

Rick

[ddevecka]

Here is the Sh controller T1

T1 0/0 is up.

Applique type is Channelized T1

Cablelength is long gain36 0db

Description: **Bunker 1**

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20040108, FPGA: 11

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

CRC Threshold is 320. Reported from firmware is 0.

Data in current interval (9 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Total Data (last 24 hours)

12859 Line Code Violations, 12576 Path Code Violations,

3 Slip Secs, 72521 Fr Loss Secs, 24 Line Err Secs, 3 Degraded Mins,

15 Errored Secs, 7 Bursty Err Secs, 9 Severely Err Secs, 72552 Unavail Secs

T1 0/1 is up.

Applique type is Channelized T1

Cablelength is long gain36 0db

Description: **Bunker 2**

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20040108, FPGA: 11

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

CRC Threshold is 320. Reported from firmware is 0.

Data in current interval (10 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Total Data (last 24 hours)

0 Line Code Violations, 0 Path Code Violations,

4562 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,

4562 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

[Richard Burts]

Dan

Thanks for posting the output of show controller. I note that both of the controllers are showing clock source is line, which I believe is probably what you want. You can check that against the config of the original router.

Also looking at the error counts on the T1 controller I feel that your problem is most likely a problem with the T1. The number of line code violations and the number of path code violations are indicators of this. Also the number of frame loss seconds.

Your original post indicated that you were having the T1 tested. I hope that the provider is testing and will confirm that there has been a problem with the circuit.

HTH

Rick

[ddevecka]

They tested and said the problem was on our end, but for now the problem has corrected it self. HMMMM.

[Richard Burts]

Dan

Lets hope it stays fixed. I have had numerous experiences where they tested circuits, claim that they did not fix anything, but the problem went away. I hope you are having a similar experience.

HTH

Rick