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New Member

T1 Controller errors

Hi

I have two customers for whom I recently installed a Cisco IPT system. Both utilize the 2651xm-v with a MFT card to terminate their PRI. Both of them show constant accumulation of timing errrors on the controller. Here's the output from show controller t1 from one of them

Data in current interval (58 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

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

3 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,

6017 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,

6017 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

I'm not experiencing any dropped calls but it still worries me.

I started with ios 12.3(1a) on both but downgraded to 12.2(15)T5 on one of them on the suggestion of a TAC engineer without any change.

I've verify my controller settings linecode/frame/clock are correct and I've tried adjusting the cablelength settings.

These two particular customers are in different cities with different providers. One gateway sits 10 feet from the smartjack and the other is about 100 feet away.

I don't have this problem on customers using other hardware (7750 mrp, 4224 etc).

Any suggestions?

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions
Silver

Re: T1 Controller errors

If these routers have an AIM-voice-30 card and a T1 VWIC, add the following commands -

network-clock-participate wic 0

network-clock-select 1 t1 0/0

Assumes the T1 is in slot 0. If it is in slot 1 , make them as follows :

network-clock-participate wic 1

network-clock-select 1 t1 0/1

Without these commands, the AIM card does not sync itself to the clock signal that is recovered off the T1 line, so it essentially free runs, and can cause big problems with fax and modem calls. For normal voice calls the clock slips are generally imperceptible.

12 REPLIES
New Member

Re: T1 Controller errors

I have had your issue in the past. T1 errors, although calls appear to be working just fine.. If you're internal wiring was extended by someone other then telco, chances are the transmit and receive pairs may need to be flipped at the extended demarc. Wirirng contractors tend to yield to industry spec...telco's sometimes try to define their own :)

Silver

Re: T1 Controller errors

If these routers have an AIM-voice-30 card and a T1 VWIC, add the following commands -

network-clock-participate wic 0

network-clock-select 1 t1 0/0

Assumes the T1 is in slot 0. If it is in slot 1 , make them as follows :

network-clock-participate wic 1

network-clock-select 1 t1 0/1

Without these commands, the AIM card does not sync itself to the clock signal that is recovered off the T1 line, so it essentially free runs, and can cause big problems with fax and modem calls. For normal voice calls the clock slips are generally imperceptible.

New Member

Re: T1 Controller errors

Hi,

I'm running a 2651XM-V with an AIM-voice-30 card and VWIC-1MFT-E1 [IOS 12.3(1a)]. I too was getting the line errors mentioned above, and added the two 'network-clock' commands suggested. This did indeed resolve that issue, however, i'm still getting Line Code violations etc. The telco has confirmed that all is ok as far as they are concerned. Just wondered whether there were any other commands/suggestions i could try?

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20020812, FPGA: 11

Framing is CRC4, Line Code is HDB3, Clock Source is Line.

Data in current interval (204 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)

78 Line Code Violations, 7 Path Code Violations,

0 Slip Secs, 0 Fr Loss Secs, 4 Line Err Secs, 0 Degraded Mins,

4 Errored Secs, 2 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

New Member

Re: T1 Controller errors

Hi,

I'm still getting errors (see below), and have provided some more info, in case anyone else has encountered the same problem. Any advice would be appreciated:

R1#sh controll e1 0/1 brie

E1 0/1 is up.

Applique type is Channelized E1 - balanced

Description: - outgoing isdn link to BT - ** IMGB271611 **

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20020812, FPGA: 11

Framing is CRC4, Line Code is HDB3, Clock Source is Line.

Data in current interval (635 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)

301 Line Code Violations, 41 Path Code Violations,

4 Slip Secs, 0 Fr Loss Secs, 16 Line Err Secs, 0 Degraded Mins,

12 Errored Secs, 3 Bursty Err Secs, 5 Severely Err Secs, 0 Unavail Secs

I've added the following 2 commands:

network-clock-participate wic 1

network-clock-select 1 E1 0/1

Here is the output from my config:

interface Serial0/1:15

no ip address

no logging event link-status

isdn switch-type primary-net5

isdn overlap-receiving

isdn incoming-voice voice

isdn map address * plan privacy type unknown

isdn sending-complete

no cdp enable

Debug info:

R1#debug isdn q921

debug isdn q921 is ON.

Dec 27 18:55:57.408: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:55:57.416: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:56:07.417: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:56:07.425: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:56:17.425: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:56:17.429: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:56:27.430: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:56:27.438: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:56:37.438: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:56:37.442: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:56:47.446: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:56:47.458: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:56:57.459: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:56:57.467: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:57:07.467: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Dec 27 18:57:07.471: ISDN Se0/1:15 Q921: User RX <- RRf sapi=0 tei=0 nr=109

Dec 27 18:57:17.472: ISDN Se0/1:15 Q921: User TX -> RRp sapi=0 tei=0 nr=23

Cisco Employee

Re: T1 Controller errors

From the output it seems that sometimes in last 24hr there were some errors.. I dont believe the controller is registering any errors at the moment. Please clear the counters on the controller and check once again. Also from the output the controller has not seen any errors for over 10 min.

Hope that helps...

Regards,

ketan

New Member

Re: T1 Controller errors

Thanks for your feedback Ketan.

I cleared the counters, and still have errors clocking. The telco says that there are no issues on their side....Any thoughts?

E1 0/1 is up.

Applique type is Channelized E1 - balanced

Description: - outgoing isdn link to BT - **

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20020812, FPGA: 11

Framing is CRC4, Line Code is HDB3, Clock Source is Line.

Data in current interval (106 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 20 15 minute intervals):

19 Line Code Violations, 1 Path Code Violations,

0 Slip Secs, 0 Fr Loss Secs, 1 Line Err Secs, 0 Degraded Mins,

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

Silver

Re: T1 Controller errors

We have seen issues like this in the past when the signal level from the Telco is too high (hot) - we suspect it causes reflections on the interface (an E1/T1 is a transmission line after all!). A pulse from the Telco equipment goes down the balanced transmission line to the router, but rather than all the energy getting absorbed by the 120 ohm termination, some of the energy is reflected back , so it is out of phase with the next incoming pulse and part of the signal is cancelled out.

It always ends up as a screaming match with the telco - they blame us, we blame them ... If at all possible see if the Telco can drop their TX level from their gear towards the router. Another hack we have used in the past is to put back to back 120 ohm to 75 ohm baluns (120-75-75-120) on the router RX leads - the insertion loss of the 2 baluns is enough to drop the signal level down and this clears up the reflections and hence the errors go away. Even a 100 metre drum of cat5 has been known to work, it drops the signal level enough,

New Member

Re: T1 Controller errors

Thanks for the very informative reply. It's good to know that the issue has been detected in the field before, and i agree, that these cases, like some others, involve issues between yourselves and the telco.

I will try out some of your suggestions, and see if this helps. I will of course update this board as soon as i have an update.

Thanks again.

New Member

Re: T1 Controller errors

Hi

I am facing exactly the same problem with VWIC-2MFT-g.703 and NM-1CE2B, the line code and path code errors continue to increase, I know for sure that there are no errors on the telco link, becasue G.703-V.35 Interface convertoers work perfectly fine on the same network, I got your idea of high signal level, and will really appreciate if there is any information regards the acceptible signal level on VWICs, I am thinking of designing a network attenuator to bring down the signal level, may be this will resolve the problem for ever for every on out there.

Also its my experience that if this problems persists for days the performance degrades and VWICs stop working, the only solution that I found working was to issue microcode reload e1 0/0 ... command.

Regards

Jawwad

jawwadh19@yahoo.com

New Member

Re: T1 Controller errors

We went through something like this for months trying to resolve errors on an MFT WIC in a 3640. Symptoms were popping/clicking noise and disconnects on the phone at our end. Telco line was clean according to a very expensive T-Berd, but we were logging thousands of errors in a 15-minute interval. A T1 CSU/DSU on the same circuit recorded no errors, as did the T-Berd. Ultimately, Cisco decided that the MFT controller was overly sensitive to certain line conditions that were (apparently) within technical specs. The solution was to insert a 3rd-party CSU in the circuit between the Telco demarc (Smartjack) and the MFT. I bothered me to cover up the error rather than solve it, but I'm pragmatic enough to accept it. Long version on request.

Blue

Re: T1 Controller errors

I would definately like to hear the long version....I am currently experience similar issues with my PRI lines from the Telco. High amounts of linecode violoations, etc. Everything, physically anyway, runs clean from telco to us, us from smart jack. Telco has been out numerous times, P1 TAC case and we are all stumped. Anyway, details and maybe a TAC case number would be very nice.

Anonymous
N/A

Re: T1 Controller errors

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