Troubleshooting excessive collisions

prashanttyagi1 · ‎10-15-2004

I have a Cisco 2500 series router that is connected to the Frame relay circuit on one end and to a 4500 series catalyst switch on the other.

I notice excessive collisions on the router occuring every once in a while (multiple times a week). I read the Cisco's article about excessive collisions but that didn't help much. I tried changing the ethernet cable from Router to the switch. Changed a few network cards on few machines that had too many collisions on the switch ports, but it still the same problem.

Here's the log from the router

Syslog logging: enabled (0 messages dropped, 0 flushes, 0 overruns)

Console logging: level debugging, 24431 messages logged

Monitor logging: level debugging, 1 messages logged

Trap logging: level informational, 24432 message lines logged

ollisions. TDR=3

Oct 13 12:06:37: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:37: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=2

Oct 13 12:06:38: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=2

Oct 13 12:06:40: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:06:41: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:42: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:06:42: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:43: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:06:43: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=2

Oct 13 12:06:44: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:45: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:06:45: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:46: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=2

Oct 13 12:06:46: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:47: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:47: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=2

Oct 13 12:06:51: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:53: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:54: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:54: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:06:54: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:56: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:06:56: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:06:57: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:06:59: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:00: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:01: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:01: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=4

Oct 13 12:07:02: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:04: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=2

Oct 13 12:07:05: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:06: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:07: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:08: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:08: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=2

Oct 13 12:07:10: %LANCE-5-COLL: Unit 0, excessive collisions. TDR=3

Oct 13 12:07:11: %LANCE-5-COLL: Unit 0, excessive

Any ideas?

Thanks

kuldeeprawat · ‎10-15-2004

Have you check the duplex settings on all your connected devices,

It should match and all should have one settings.

Like if you have set 100Mbps Full Duplex at one end and half duplex is running on the other end, can give you a problem.

Thanks

prashanttyagi1 · ‎10-19-2004

Hi,

Thanks for the reply.

You mean all the devices that are connected to the switch? There are atleast 100 of them. Do I have to check all of them one by one?

Thanks

Kevin Dorrell · ‎10-19-2004

You only have to check the switchport where the 2500 is connected. That should be configured half-duplex. Auto would work as well, but if the 2500 is fixed half- it's best to pin down the switch port as well. The switch port should definitely not be forced full-duplex.

Kevin Dorrell

Luxembourg

prashanttyagi1 · ‎10-19-2004

Kevin

Thanks for the reply. I did check the 4600 switch port where 2500 is connected, it's set to 10Mbps Half Dup.

I also wanted to check if the router has the same mode or auto, but it doesn't show the mode in "sh interface ethernet 0" output.

This is what I'm getting for sh int eth 0

Hardware is Lance, address is 0000.0c5d.b089 (bia 0000.0c5d.b089)

Internet address is *.*.*.* 255.255.255.0

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 3/255

Encapsulation ARPA, loopback not set, keepalive set (10 sec)

ARP type: ARPA, ARP Timeout 4:00:00

Last input 0:00:00, output 0:00:00, output hang never

Last clearing of "show interface" counters 0:00:00

Output queue 0/40, 5199 drops; input queue 0/75, 2349 drops

5 minute input rate 175000 bits/sec, 74 packets/sec

5 minute output rate 154000 bits/sec, 81 packets/sec

65147367 packets input, 450688150 bytes, 40 no buffer

Received 6219128 broadcasts, 0 runts, 0 giants

77 input errors, 0 CRC, 0 frame, 0 overrun, 77 ignored, 0 abort

0 input packets with dribble condition detected

68740157 packets output, 1830942983 bytes, 0 underruns

8619 output errors, 710095 collisions, 0 interface resets, 0 restarts

0 output buffer failures, 0 output buffers swapped out

Kevin Dorrell · ‎10-19-2004

Which model of 2500 are you using? My 2520 here has a choice of 10BaseT on and RJ45, or AUI. In the configuration, you can specify the command media-type AUI. According to the documantation, AUI is the default. But the strange thing is, I don't see the command when I do a wr term or a show run, even if I select the non-default 10BaseT.

But that's not the point. The point is, if you have a dual-interface model, have you set the media-type correctly? Which are you using?

Kevin Dorrell

Luxembourg

Kevin Dorrell · ‎10-16-2004

This 2500 router, does it have an AUI port for the Ethernet, to which there is a transceiver attached? If so, there will be a small switch on the transceiver called "SQE". Switch it off.

If there are any transceivers on the network, make sure they have the SQE switched off.

http://www.cisco.com/warp/public/86/12.html

Kevin Dorrell

Luxembourg

prashanttyagi1 · ‎10-19-2004

Kevin,

I did check the AUI port where the transceiver is attached. The SQE switch is already off.

Any other ideas?

Kevin Dorrell · ‎10-19-2004

Do you have any other transceivers on the network? If I remember rightly, other transceivers with the the SQE switch on can provoke the same effect. But this only applies in a hub environment, where there is one collision domain covering all ports.

BTW, check again - some of these transceivers have ambiguous switch setting labels. One of mine was labeled "SQE disable ON" - what does that mean?

Kevin Dorrell

Luxembourg

raovaranasi · ‎12-11-2010

Hi,

If someone knows about Kronos clock, please help me by confirming about the fix. the clock is connected to 2960 and negotiating with 10/H. But switch side the port is configured as auto/auto. i think this leads the collisions in the 2960 switch port due to bad performance.

If i hard code the switch port settings as 10/H, will it fixes the issue?? Please respond...

Rao