E1 Controller line code violations question

Unanswered Question
Jul 31st, 2008

Newlly deployed a 2811 router with two E1s MLPPP bunddle new brach office, at first all seem fine connected to MPLS provider. Then hours later users began complaining, looking at the E1 noticed lots of line code violations and one of the E1 keeps dropping from bundle.

MPLS provider says no issue on the trouble circuit, I have insisted and issue have been escalated.

I verified with provider clock source to be line properly configured.

Is there any way a bad controller can be the cause of line code violations, my understanding is the this could be trigger by either bad smart jacks or whatever at the CO side. I am using VWIC-2MFT-G703, if card was bad I would see the other E1 port bad but the other E1 is fine.

Im out of ideas, only thing I could do is invert the E1 circuit connections and place new cables and see hat happens.. this is very bad.

Any ideas?

E1 0/0/0 is up.

Applique type is Channelized E1 - balanced

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20060623, FPGA: 20, spm_count = 0

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

CRC Threshold is 320. Reported from firmware is 320.

Data in current interval (632 seconds elapsed):

2523 Line Code Violations, 1889 Path Code Violations

69 Slip Secs, 0 Fr Loss Secs, 373 Line Err Secs, 6 Degraded Mins

389 Errored Secs, 259 Bursty Err Secs, 27 Severely Err Secs, 0 Unavail Secs

Total Data (last 7 15 minute intervals):

135210 Line Code Violations, 62598 Path Code Violations,

684 Slip Secs, 0 Fr Loss Secs, 4283 Line Err Secs, 58 Degraded Mins,

3820 Errored Secs, 2935 Bursty Err Secs, 683 Severely Err Secs, 461 Unavail Secs


Serial0/0/0:0 is up, line protocol is up

Hardware is GT96K Serial

MTU 1500 bytes, BW 1984 Kbit, DLY 20000 usec,

reliability 209/255, txload 1/255, rxload 1/255

Encapsulation PPP, LCP Open, multilink Open

Link is a member of Multilink bundle Multilink1, loopback not set

Keepalive set (10 sec)

Last input 00:00:00, output 00:00:01, output hang never

Last clearing of "show interface" counters 01:56:38

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 4

Queueing strategy: weighted fair [suspended, using FIFO]

FIFO output queue 0/40, 4 drops

5 minute input rate 3000 bits/sec, 3 packets/sec

5 minute output rate 3000 bits/sec, 4 packets/sec

8406 packets input, 1604873 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

55157 input errors, 55157 CRC, 9910 frame, 10 overrun, 0 ignored, 7369 abort

10946 packets output, 1002750 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

2 carrier transitions

Timeslot(s) Used:1-31, SCC: 0, Transmitter delay is 0 flags

code use


controller used:


I have this problem too.
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tdrais Thu, 07/31/2008 - 09:52

Not sure if its your problem but when you set both to line and the clocks are slightly different between the 2 lines you get lots of slips. This card unlike the newer vwic2 cards only has a single clock.

Although it has not completely correct this when I have slip issue if you set one of the lines to internal it will take the clock from the other line.

In your case you are getting UNAVAIL seconds which generally means you have more than just a simple slipped clock.

JORGE RODRIGUEZ Thu, 07/31/2008 - 10:58

Hi Tim,

Thanks for the reply, I will see the results tonight, provider told me it will send a tech to Tbird the lines to investigate fruther. This is a office branch in Honkong, we have same in London, same router, same controllers and there is no issues.


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