[c-nsp] Strange OC3 issue between GSR and old POSIP card in 7507

[Bill Wichers]

I'm seeing a strange problem with an OC3 link that should be really
simple. The link runs from a 4-port OC3 card in a 12012 to an old
POSIP-OC3-50 in a 7507. Earlier in the day one of the two POSIP cards in
the 7507 started running a *lot* of receive errors, all CRC, so we
thought maybe the optic died. We traded the link to a second POSIP card
in the same 7507 (GSR port was the same in both cases). The link came
right up, started running around 60-70Mb/s and was clean.

 

We then noticed the dCEF wasn't running so tried starting that. That
caused a bunch of line card reloads. We tried doing a complete reload of
the entire chassis, which took down dCEF but .... Brought back the same
weird problem on the second OC3 linecard! 

 

Normally I'd think the RX level on the POSIP was too high and burned out
the received, but we're down around -14dB or so (it's a singlemode link,
IR optics). I can't figure out why the link would have worked before the
reload but not after either since the optics weren't touched. 

 

Does anyone have any ideas? I've already checked light levels, CRC (set
the same on both ends - CRC16), clocking is line on one end, internal on
the other, all the other settings are identical on both ends. What is
happening right now is that the line shows "up" on both ends, but line
protocol is going up/down on about 20 second cyles:

 

Mar 25 14:00:01: %LINEPROTO-5-UPDOWN: Line protocol on Interface
POS6/0/0, changed state to down

Mar 25 14:00:11: %LINEPROTO-5-UPDOWN: Line protocol on Interface
POS6/0/0, changed state to up

Mar 25 14:00:31: %LINEPROTO-5-UPDOWN: Line protocol on Interface
POS6/0/0, changed state to down

Mar 25 14:00:41: %LINEPROTO-5-UPDOWN: Line protocol on Interface
POS6/0/0, changed state to up

Mar 25 14:01:01: %LINEPROTO-5-UPDOWN: Line protocol on Interface
POS6/0/0, changed state to down

Mar 25 14:01:11: %LINEPROTO-5-UPDOWN: Line protocol on Interface
POS6/0/0, changed state to up

 

I've tried doing a 'shut / no shut' on both ends to reset the interface
but that doesn't change anything. I've pretty much run out of ideas at
this point... Any help is appreciated.

 

   -Bill

 

We show the following on the links (IPs changed to private net):

 

7507:

POS6/0/0 is up, line protocol is up

  Hardware is cyBus Packet over Sonet

  Description: OC-3 to GSR-Core-Right

  Internet address is 172.16.1.1/30

  MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec,

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

  Encapsulation HDLC, loopback not set

  Keepalive set (10 sec)

  Scramble disabled

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

  Last clearing of "show interface" counters 00:18:34

  Queueing strategy: fifo

  Output queue 0/40, 0 drops; input queue 0/75, 0 drops

  30 second input rate 0 bits/sec, 0 packets/sec

  30 second output rate 1000 bits/sec, 1 packets/sec

     180 packets input, 9873 bytes, 0 no buffer

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

              0 parity

     3 input errors, 3 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     722 packets output, 85050 bytes, 0 underruns

     0 output errors, 0 applique, 71 interface resets

     0 output buffer failures, 0 output buffers swapped out

     1 carrier transitions

 

12012:

POS3/3 is up, line protocol is down

  Hardware is Packet over SONET

  Internet address is 172.16.1.2/30

  MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec, rely 255/255, load 1/255

  Encapsulation HDLC, crc 16, loopback not set

  Keepalive set (10 sec)

  Scramble disabled

  Last input 02:04:33, output 00:00:03, output hang never

  Last clearing of "show interface" counters 00:42:02

  Queueing strategy: fifo

  Output queue 0/40, 0 drops; input queue 0/75, 0 drops

  30 second input rate 0 bits/sec, 0 packets/sec

  30 second 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

              0 parity

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     203 packets output, 11126 bytes, 0 underruns

     0 output errors, 0 applique, 8 interface resets

     0 output buffer failures, 0 output buffers swapped out

     4 carrier transitions

 

    -Bill