T1 CRC errors, router unresponsive

Below is the info from the other side.  It seems if I shut down the interface on router2, then plug the line back into router1 it's OK until I no shut on router2 again.

router2#show int s0/0
Serial0/0 is up, line protocol is down 
  Hardware is PQUICC with Fractional T1 CSU/DSU
  Internet address is 10.255.255.1/30
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, 
     reliability 254/255, txload 1/255, rxload 1/255
  Encapsulation PPP, LCP Listen, loopback not set
  Keepalive set (10 sec)
  Last input 00:43:15, output 00:00:12, output hang never
  Last clearing of "show interface" counters 00:04:19
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops) 
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 1158 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     1 input errors, 0 CRC, 1 frame, 0 overrun, 0 ignored, 0 abort
     10 packets output, 140 bytes, 0 underruns
     0 output errors, 0 collisions, 4 interface resets
     0 output buffer failures, 0 output buffers swapped out
     1 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

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Thought I'd add this too from show controlers

PowerQUICC SCC specific errors:
4201848 input aborts on receiving flag sequence
0 throttles, 0 enables
0 overruns
0 transmitter underruns
0 transmitter CTS losts
2180415 aborted short frames 

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If CRC is inreasing it is not related with your configuration. Please check below steps.
  - T1 Module on router
  - Cable between T1 module and Modem
  - Modem.
  - ISP physal line

please give loop over your modem to your router side. you will see your interface status (looped) send ping to your interface. if CRC is not inreasing ISP physical line has problem.
If increasing;
  - lets connect RJ45 sockets for T1 connection as below.
        1 -> 4
        2 -> 5
        4 -> 1
        5 -> 2

you have to see looped. if ok check cable and modem. if  not change t1 module.

"please give loop over your modem to your router side. you will see your interface status (looped) send ping to your interface"
I'm not sure exactly what you mean here.  Can you explain?

I did try pushing the loopback button on router1's T1 card.  This time router2 was unresponsive and show errors.

(after shutting down int again)
router2#show int s0/0
Serial0/0 is administratively down, line protocol is down 
  Hardware is PQUICC with Fractional T1 CSU/DSU
  Internet address is 10.255.255.1/30
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, 
     reliability 249/255, txload 1/255, rxload 1/255
  Encapsulation PPP, LCP Closed, loopback not set
  Keepalive set (10 sec)
  Last input 01:33:56, output 00:00:29, output hang never
  Last clearing of "show interface" counters 00:55:01
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops) 
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 1158 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     6124403 input errors, 5823477 CRC, 218658 frame, 0 overrun, 0 ignored, 82268 abort
     57 packets output, 798 bytes, 0 underruns
     0 output errors, 0 collisions, 17 interface resets
     0 output buffer failures, 0 output buffers swapped out
     8 carrier transitions
     DCD=down  DSR=up  DTR=down  RTS=down  CTS=down

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loopback bottom on card will give remote loopback. in this time, you will see everthing down. but remote system will see looped.
Loop means, TX and RX will crossconnect. after physically loop you will see

router2#show int s0/0
Serial0/0 is administratively up, line protocol is up (looped)
Hardware is PQUICC with Fractional T1 CSU/DSU

it has to be loopback button on your modem. It has 2 option, local and remote
Local : it will give from v35 to local router,
Remote : it will give from HDSL to ISP router.
You need to make local  test.

Sounds like a carrier issue.  There are a large amount of short frames, and input errors on the remote site.  Maybe worth giving them a call to investigate as there maybe a problem with a PE or other intermediate devices.

ArronG

It's hard to perform the test because one there are errors it makes the router entirely unresponsive or too slow to even accept a command.  It's odd that it happened just a few hours after I changed the queueing, but the provider is taking responsibility at this point so they need to fix their equipment.  Thanks for the help!

Any insight into how I can prevent this from taking down the router though?  There is a DSL line for redundancy, but it won't help if the router is frozen!