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New Member

T1 issues - Path Code Violations

Recently our Company has begun migrating our T1 lines to a 7206VXR router with PA-MCX-8TE1, however one location began "dropping off" for a few seconds serveral times a day. checking the controllers there is an increasing number of Path Code violations on both routers (Remote end has a 1760 with wic1-dsu-t1.) I have checked with the ISP and they have stated that everything looks good, and that they are not doing anything with the line coding. and I have swapped routers out on both ends now, (2650 series here, another 1760 on the remote end.) This seems to reduce the amount of errors, however I can still see the router drop off for a few seconds about once a day. Path codes are still increasing on both ends. I have tried different LBO settings on the 7206 before moving to the 2651 and none seem to help. (line from router to smart jack here is about 340 feet, line from smart jack to router at remote location is about 150 feet) anyway At this point I am leaning torwards it being a problem with the line that they have stated is good, but I would like to know if there is anything else I could try -(I have checked cables, swapped ports, upgraded IOS, messed with the LBO setting and eventually swapped routers)before contacting the ISP for the 3rd time. - Thanks

New Member

Re: T1 issues - Path Code Violations

Has the Telco done a bit error rate test and do they see errors on the circuit?

Does framing drop during the outages?

Is your clocking and framing setup correctly, are you seeing slips?

New Member

Re: T1 issues - Path Code Violations

1. Yes - according to them it looked o.k.

2. It appears it is dropping frames: and I am not seeing slips

3. Clocking is setup properly, linecoding is B8ZS framing is ESF.

Have tried different combinations of linecoding and Framing to no avail. Now according to the Telco they are not doing anything to affect linecoding or framing, that this is completley controlled by my router - I was under the impression that they controlled the Framing and Line code, but the Tech I talked to said that was dependent on my routers. (of course he also stated that if a circuit is having problems it will be down completly and if it's up then it's probalby not broke.)

Last clearing of alarm counters 1w4d

loss of signal : 1, last occurred 1w4d

loss of frame : 77, last occurred 02:08:05

AIS alarm : 63, last occurred 02:08:05

Remote alarm : 8, last occurred 2d20h

Module access errors : 0,

Total Data (last 96 15 minute intervals):

0 Line Code Violations, 1957 Path Code Violations

0 Slip Secs, 33 Fr Loss Secs, 0 Line Err Secs, 33 Degraded Mins

35 Errored Secs, 6 Bursty Err Secs, 14 Severely Err Secs, 19 Unavail Secs

Data in current interval (90 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

New Member

Re: T1 issues - Path Code Violations


Depending on your router IOS you might have a bug and also I remember I had Cisco replacing my WIC(same as yours) because they had a hadware problem from factory. If I find the bug, I'll post it here.

I am having a similar problem but only on one side and with a 1760 router. I also had the Telco checking the circuit an everything came out clear.

Have you done loopback test on your router interface? This is my next step.

Take a look at this link:

Let me know if it helps.

New Member

Re: T1 issues - Path Code Violations

Yes that is what I was hoping - I upgraded to the most stable releases of IOS I could find, but it did not seem to help - I have already had to upgrade the IOS on the 7206 for a similiar issue. I have been through that Link already - That is where I came up with what to do with the path code errors - Still a Good Article though.

New Member

Re: T1 issues - Path Code Violations

I suggest you to check the electrical neutralization and also be sure of the chassis grounding.

Not completely an IT solution but worth to try.

New Member

Re: T1 issues - Path Code Violations

Couldn't hurt to try I will have to drive back to the remote location and check it.


Re: T1 issues - Path Code Violations

To eliminate your demark extension cabling you can do your own bert test on that. Put a loopback jack on the cable end that connects to the smartjack and run the bert from the router.

New Member

Re: T1 issues - Path Code Violations

Thanks I did not know you could do that unfortuantely I am in class all week so I will have to try that on my return next week

New Member

Re: T1 issues - Path Code Violations

I know its been awhile but I wanted to put some closure on this, Someone else started looking at this while I was in class, and his solution was to move a T1 that we had recently quit using to this location. I can't say I really agreed with this however it does appear that after moving to a new T1 it is no longer flapping. Thanks to everyone who responded on this.