Late collisions and interface reset

Unanswered Question
Feb 27th, 2007

I'm getting a lot of late collisions on the WAN side of my router (Cisco 2801.) In the log I am also seeing errors every few minutes where that interface will come back up. I am having throughput issues with this router and I think this may be a duplex mismatch. Does this sound right?

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
wcraft.htawork Tue, 02/27/2007 - 09:23

rtr#sh int

FastEthernet0/0 is up, line protocol is up

Hardware is Gt96k FE, address is 0019.2fa4.38f8 (bia 0019.2fa4.38f8)

Description: $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-FE 0$$ES_LAN$$FW_INSIDE$

Internet address is 10.10.10.1/24

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

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

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

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

Last clearing of "show interface" counters never

Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 4000 bits/sec, 3 packets/sec

5 minute output rate 2000 bits/sec, 2 packets/sec

15086034 packets input, 88230789 bytes

Received 4353489 broadcasts, 0 runts, 0 giants, 0 throttles

2 input errors, 0 CRC, 0 frame, 1 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

11475289 packets output, 3392575167 bytes, 0 underruns

0 output errors, 0 collisions, 2 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

FastEthernet0/1 is up, line protocol is up

Hardware is Gt96k FE, address is 0019.2fa4.38f9 (bia 0019.2fa4.38f9)

Description: $ES_WAN$$FW_OUTSIDE$$ETH-WAN$

Internet address is 66.101.199.34/30

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

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

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Half-duplex, 100Mb/s, 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

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

Last clearing of "show interface" counters never

Input queue: 0/75/39/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 9000 bits/sec, 14 packets/sec

5 minute output rate 3000 bits/sec, 3 packets/sec

29679920 packets input, 335398060 bytes

Received 18194333 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 watchdog

0 input packets with dribble condition detected

11108075 packets output, 3375348659 bytes, 0 underruns

27501 output errors, 22690 collisions, 26708 interface resets

0 babbles, 27613 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

NVI0 is up, line protocol is up

Hardware is NVI

MTU 1514 bytes, BW 10000000 Kbit, DLY 0 usec,

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

Encapsulation UNKNOWN, loopback not set

Last input never, output never, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

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

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

0 packets output, 0 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

rtr#

deilert Tue, 02/27/2007 - 09:25

that is correct Late Collisions are generally caused by a duplex mismatch

Amit Singh Tue, 02/27/2007 - 09:33

Your WAN FE interface is working as 100MB half duplex, that's why you are getting a lots of late collisions and output errors. Please check the duplex part on the other side and match it. It should be fine after the settings are same at both the sides.

-amit singh

wcraft.htawork Tue, 02/27/2007 - 13:48

Yep - was able to force it to Full Duplex/100Mbps and the late collisions have stopped. Thanks for the feedback.

Actions

This Discussion