[nsp] a difference between Catalyst 3550 and 3500XL FastEthernet ports

Andrey Koklin aka at veco.ru
Fri Jul 4 15:23:40 EDT 2003


Hi,

There is a problem, when I connect pair of DSL modems (WaiLAN AGate 700C/R)
to Catalysts 3550-24T. With any port settings, the connection gives big
number of CRC errors (~10%):

sbyt-c3550#sh int fa0/23
FastEthernet0/23 is up, line protocol is up 
  Hardware is Fast Ethernet, address is 000a.f4d2.9b17 (bia 000a.f4d2.9b17)
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, 
     reliability 253/255, txload 9/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Half-duplex, 10Mb/s
  input flow-control is off, output flow-control is off
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:01, output 00:00:06, output hang never
  Last clearing of "show interface" counters 23w0d
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue :0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 391000 bits/sec, 1 packets/sec
     937354 packets input, 331634503 bytes, 0 no buffer
     Received 72587 broadcasts, 0 runts, 77 giants, 0 throttles
     77143 input errors, 77066 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 42183 multicast, 0 pause input
     0 input packets with dribble condition detected
     949543 packets output, 238543372 bytes, 0 underruns
     0 output errors, 5752 collisions, 0 interface resets
     0 babbles, 0 late collision, 12193 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out

In the same time, it makes clean connection, if I plug the same modem
into Catalyst 3548 port:

$ rsh c3548-1-1 sh int fa0/29
FastEthernet0/29 is up, line protocol is up 
  Hardware is Fast Ethernet, address is 0004.6dfb.925d (bia 0004.6dfb.925d)
  Description: EnegroSbyt, AGate 700C
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Half-duplex, 10Mb/s, 100BaseTX/FX
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:28:26, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     499076 packets input, 164921128 bytes
     Received 69589 broadcasts, 0 runts, 1 giants, 0 throttles
     1 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 10516 multicast
     0 input packets with dribble condition detected
     523738 packets output, 161193342 bytes, 0 underruns
     0 output errors, 1383 collisions, 3 interface resets
     0 babbles, 0 late collision, 4852 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out

(it's real situation now, one side pluged into 3550, another - into 3548.
If I plug them both into 3550s, there're CRC errors on both sides)

And, of course, it makes clear connection, if I plug DSL modem into PC.

Had anyone experienced something similiar? Do there exist a remedy?

After trying to tune Ethernet port settings, I suppose the situation
with c3550--AGate connection looks hopeless, there is needed additional
hub/repeater, if I should connect the modem to Catalyst 3550 directly.
Also, the situation is persistent for any 3550 software version.

-- 
Regards,
Andrey


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