Need help with 1224R T1 issue

[madmike]

I have a 1224R I bought used. I should be clear that I'm used to Cisco gear and some of the older Adtran CSU/DSU's from days gone by. Trying to get a new T1 up but it keeps throwing alarms and dropping briefly. Pings across the link are unreliable with some dropped packets and latency reported between 14ms to 400ms+. Looking at the T1 interface while connected to the carrier shows some errors on the TX side (LOF, LOS, AIS), RX never reports errors that I have seen. What concerns me are the errors under the TDM group (PPP). Errors are incrementing at an incredible rate with little to no traffic. I'll paste an example in at the end of this post. Now what really bugs me is I'm trying to prove to the carrier that the issue is not mine, but until I can explain the errors I'm seeing, I have little faith that they will see it my way. I have done the following: I put a hard loopback plug in the original NIM and ran the QRSS test continuously. No errors on the T1 interface, but continuously incrementing errors under PPP. Replaced the original single T1 NIM with a dual T1 NIM, tested as above and same results. Finally, I made a hard loopback jack to eliminate my cabling as an issue and get the same results (posted below). Any help would be appreciated.

t1 1/1 is IN TEST
  Description: Windstream Service over Vz
  Receiver has no alarms
  T1 coding is B8ZS, framing is ESF
  Clock source is internal, FDL type is ANSI
  Line build-out is 0dB
  No remote loopbacks, No network loopbacks
  Acceptance of remote loopback requests enabled
  In Test: Sending QRSS pattern
  Tx Alarm Enable: rai
  Last clearing of counters 00:10:31
    loss of frame  : 0
    loss of signal : 0
    AIS alarm      : 0
    Remote alarm   : 0

  DS0 Status: 123456789012345678901234
              NNNNNNNNNNNNNNNNNNNNNNNN
  Status Legend: '-' = DS0 is unallocated
                 'N' = DS0 is dedicated (nailed)

  Line Status: -- No Alarms --

  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
  Current Performance Statistics:
    0 Errored Seconds, 0 Bursty Errored Seconds
    0 Severely Errored Seconds, 0 Severely Errored Frame Seconds
    0 Unavailable Seconds, 0 Path Code Violations
    0 Line Code Violations, 0 Controlled Slip Seconds
    0 Line Errored Seconds, 0 Degraded Minutes

  TDM group 1, line protocol is DOWN
  Encapsulation PPP (ppp 1)
    6 packets input, 72 bytes, 0 no buffer
    0 runts, 0 giants, 0 throttles
    3338184 input errors, 183505 CRC, 1431359 frame
    1723320 abort, 0 discards, 0 overruns
    6 packets output, 72 bytes, 0 underruns

[Anonymous]

- Thanks for posting your question on the forum!

Based on the output you provided, it appears that the T1 interface is in test mode and is transmitting a pattern. Try issuing the following command:

config t

int t1 1/1

no test-pattern

This will turn off the test-pattern that is currently being transmitted. Please do not hesitate to let us know if you have any further questions.

Thanks,

Noor

[madmike]

Noor, thanks for your response, however if you read through my post, you'll see I pasted the output after mentioning I ran a hard loop and QRSS test pattern. My question is why I see all the incrementing errors under the TDM group (PPP) interface even though the T1 interface is running clean. Is it cosmetic? Is there an underlying issue? I should note that I upgraded my AOS in the meantime to the latest on the site. I know there is a problem on the circuit because when I loop my cabling up to the NID, the T1 runs clean for days, but the carrier came out and saw an issue on the T1 up the line so it rules out my equipment. I just want to know if I should be concerned about all the errors under the TDM group - CRC's, input, frame, abort...I find it hard to believe that two separate NIM's would show the same problem.

Thanks,

MadMike

[Anonymous]

- I apologize for not answering your question completely. I would be wondering why those TDM errors are accruing. Usually the TDM group errors are, as you suspect, due to physical errors on the T1. To be honest, I have yet to run into a case where that has not been the issue. When you are viewing the T1 errors, are you using the "show int t1 1/1" command? The reason I ask is that the section labeled 'Current Performance Statistics' only list the errors that have occurred during that 15 minute increment. Have you viewed the "show int t1 1/1 perf tot" output? This will show you the T1 errors that have accrued in the past 24 hours (assuming that the router has not been rebooted and the counters have not be cleared). The fact that you have put 2 different T1 NIMs in place and are running into the same issue would also lead me to the same conclusion that the equipment is not to blame.

Please do not hesitate to let me know if you have any questions.

Thanks,

Noor

[Anonymous]

madmike:

Do you have further questions on this post?  If so, please do not hesitate to reply.

Levi

[Anonymous]

madmike:

I went ahead and flagged "Assumed Answered" on this post to make it more visible and help other members of the community find solutions more easily. If you feel like there is a better answer, feel free to come back to this post and select it with the applicable buttons.  If you have any additional information on this that others may benefit from, please come back to this post to provide an update.  If you still need assistance, we would be more than happy to continue working with you on this - just let us know in a reply.

Thanks,

Levi