Re: [nsp] trouble setting up a T3 crossover

From: Alastair Pooley (apooley@star.net.uk)
Date: Mon Mar 26 2001 - 10:46:47 EST


I've had a similar problem with PA-T3+ in a live environment. We had PA-T3+ connected to PA-T3+ in 7200's over an unclocked 45MB circuit. Set one end to clock source internal the other to clock source line. We then get CRC's and line code violations exactly as you describe.

We had a batch of 20 cards and not all them seem to exhibit the problem - we've commisioned new circuits, seen this problem and successfully resolved it by swapping the cards. Here's an example of one while at fault. Don't know if anyone else can shed any light on this one, but I thought the added info might help.

Cheers
Al

Serial2/0 is up, line protocol is up
  Hardware is M1T-T3 pa
  Description: 45MB to telehouse:Tanet:D3AA12330:LI55
  Internet address is 212.125.78.245/30
  MTU 4470 bytes, BW 44210 Kbit, DLY 200 usec,
     reliability 255/255, txload 10/255, rxload 23/255
  Encapsulation HDLC, crc 32, loopback not set
  Keepalive set (10 sec)
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters 6d05h
  Queueing strategy: fifo
  Output queue 0/40, 633 drops; input queue 0/75, 0 drops
  5 minute input rate 4072000 bits/sec, 834 packets/sec
  5 minute output rate 1817000 bits/sec, 836 packets/sec
     164657131 packets input, 1797374398 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
              0 parity
     2905 input errors, 2350 CRC, 0 frame, 31 overrun, 0 ignored, 524 abort
     203802811 packets output, 3993169802 bytes, 69 underruns
     69 output errors, 0 applique, 15 interface resets
     0 output buffer failures, 0 output buffers swapped out
     19 carrier transitions
   rxLOS inactive, rxLOF inactive, rxAIS inactive
   txAIS inactive, rxRAI inactive, txRAI inactive

M1T-T3 pa: show controller:
PAS unit 0, subunit 0, f/w version 2-56, rev ID 0x2800001, version 3
idb = 0x61FB2D70, ds = 0x61FB4A20, ssb=0x61FB4CF8
Clock mux=0x30, ucmd_ctrl=0x0, port_status=0x1
Serial config=0xA, line config=0x1B0202
maxdgram=4584, bufpool=128Kb, 256 particles

   rxLOS inactive, rxLOF inactive, rxAIS inactive
   txAIS inactive, rxRAI inactive, txRAI inactive
line state: up
cable type : T3 cable, received clockrate 44201430

base0 registers=0x3D000000, base1 registers=0x3D002000
mxt_ds=0x627DE1F8, rx ring entries=128, tx ring entries=256
rxring=0x722FAA0, rxr shadow=0x61FB65CC, rx_head=65
txring=0x722FF80, txr shadow=0x61FB6BF8, tx_head=252, tx_tail=252, tx_count=0
throttled=0, enabled=0
rx_no_eop_err=0, rx_no_stp_err=0, rx_no_eop_stp_err=0
rx_no_buf=0, rx_soft_overrun_err=0, dump_err= 183, bogus=0, mxt_flags=0x2C
tx_underrun_err=69, tx_soft_underrun_err=37, tx_limited=0(256)
tx_fullring=2985, tx_started=203834272
   Framing is c-bit, Clock Source is Internal
   Bandwidth limit is 44210, DSU mode 0, Cable length is 20
   rx FEBE since last clear counter 1, since reset 0
   Data in current interval (822 seconds elapsed):
     9 Line Code Violations, 3 P-bit Coding Violation
     3 C-bit Coding Violation
     3 P-bit Err Secs, 0 P-bit Sev Err Secs
     0 Sev Err Framing Secs, 0 Unavailable Secs
     6 Line Errored Secs, 3 C-bit Errored Secs, 0 C-bit Sev Err Secs
   Total Data (last 24 hours)
     583 Line Code Violations, 202 P-bit Coding Violation,
     201 C-bit Coding Violation,
     200 P-bit Err Secs, 0 P-bit Sev Err Secs,
     0 Sev Err Framing Secs, 0 Unavailable Secs,
     357 Line Errored Secs, 199 C-bit Errored Secs, 0 C-bit Sev Err Secs

   No alarms detected.
                        

----- Original Message -----
From: <jlewis@lewis.org>
To: <cisco-nsp@puck.nether.net>
Sent: Saturday, March 24, 2001 6:51 AM
Subject: [nsp] trouble setting up a T3 crossover

> I'm trying to setup a T3 between a Cisco 7500 and 3640 in the same room
> just to get the gear tested before deploying it. The 7500 is using a
> couple of PA-2T3's. The 3640 has an NM-1HSSI and a Kentrox T3 IDSU. I've
> got a pair of short coax cables (maybe 4 feet) going from xmit to rcv
> between one of the PA-2T3 T3 interfaces and the IDSU.
>
> I'm having trouble getting the T3 to run 100% clean. After playing with
> lots of settings, I think I've found that the IDSU and and PA-2T3 don't
> get along with scrambling enabled. The link will work, but takes lots of
> errors.
>
> With the framing on each end set to c-bit, one end set to get clock from
> the line, one set to internal, and scramble off, I can pass lots of
> traffic...but I get small numbers of receive CRC errors on the 7500.
>
> Router#sh in s2/0/1
> Serial2/0/1 is up, line protocol is up
> Hardware is cyBus PODS3 Serial
> Internet address is 10.255.255.1/30
> MTU 1500 bytes, BW 44210 Kbit, DLY 200 usec, rely 255/255, load 1/255
> Encapsulation HDLC, crc 16, loopback not set
> Keepalive set (10 sec)
> Last input 00:00:00, output 00:00:00, output hang never
> Last clearing of "show interface" counters 01:12:00
> 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
> 11311 packets input, 15123753 bytes, 0 no buffer
> Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
> 0 parity
> 10 input errors, 10 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
> 13387 packets output, 16452239 bytes, 0 underruns
> 0 output errors, 0 applique, 0 interface resets
> 0 output buffer failures, 0 output buffers swapped out
> 0 carrier transitions
> LC=up CA=down TM=down LB=down TA=down LA=down
>
> Router#sh contr ser 2/0/1
> Serial2/0/1 -
> Mx T3(2) HW Revision 0x3, FW Revision 3.9
> Framing is c-bit, Clock Source is Line
> Bandwidth limit is 44210, DSU mode 1, Cable length is 10
> Data in current interval (673 seconds elapsed):
> 2 Line Code Violations, 0 P-bit Coding Violation
> 0 C-bit Coding Violation
> 0 P-bit Err Secs, 0 P-bit Sev Err Secs
> 0 Sev Err Framing Secs, 0 Unavailable Secs
> 1 Line Errored Secs, 0 C-bit Errored Secs, 0 C-bit Sev Err Secs
> Total Data (last 4 15 minute intervals):
> 17 Line Code Violations, 8 P-bit Coding Violation,
> 8 C-bit Coding Violation,
> 6 P-bit Err Secs, 0 P-bit Sev Err Secs,
> 0 Sev Err Framing Secs, 0 Unavailable Secs,
> 14 Line Errored Secs, 6 C-bit Errored Secs, 0 C-bit Sev Err Secs
>
> No alarms detected.
>
> Configured for remote default subrate
>
> I've tried replacing the T3 cables (made a new set). It seems to have
> slightly more trouble with patterns of alternating 0's and 1's (0xAAAA)
> than the default pattern or all 0's or all 1's.
>
> Have I overlooked something?
>
> --
> ----------------------------------------------------------------------
> Jon Lewis *jlewis@lewis.org*| I route
> System Administrator | therefore you are
> Atlantic Net |
> _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
>
>
>
> ________________________________________________________________________
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