I have a catalyst 3560 48pt switch. Upon viewing the stats, I have 1 port that has a high number of transmit and total collisions.
Interface Unicast Multicast Broadcast Total Collisions Fa0/18 114168 344740 658914 0 Fa0/19 595186 64387 156112 0 Fa0/20 0 0 0 0 Fa0/21 404368 344732 658575 0 Fa0/22 454810 344740 655596 15717 Fa0/23 0 0 0 0
This port is connectecd to a PC. How can I find out what is causing the high collision rate for this port?
TIA Justin
I would suspect a bad nic card or ethernet cable or port speed mismatch.
Ethereal or some other packet sniffer should tell what type of packets are bad....
Check the speed and duplex settings on the switch and the pc. If they are mismatched correct the issue. Also try to move the patch cord from fa0/22 to a different port. If the problem goes away then the issue is in the switch. If the problem stays then it is in the cable plant or pc. try new patch cords or test the cable using a cable tester to make sure you do not have a bad cable. try replacing the nic in the pc or replacing the pc all together. If you still have problems then it is time to have the cable plant tested for NEXT and other interference.
Steve
just> I have a catalyst 3560 48pt switch. Upon viewing the stats, I have 1
Not at all. This is a perfectly normal collision rate.
There is not enough information here to tell if there is a missmatch or not.
There is *no* problem here.
Here is what you need to do. Check that you do not have duplex mismatch using
If you don't have a mismatch then you can decide whether you need or want to change the ports registering collisions from HD to Full Duplex. The chances are that for a PC it will make little measurable or noticable difference.
Collisions (or as Mr Siefert would now call them Contention Events) are a perfectly normal part of ethernet operation.
Plan B. You will *never* be happy until the collision counters are gone. Convert all links to FD immediately. Then carry out the same checks as above to make sure that you do not have duplex mismatches.
Thanks everyone.
I got off easy. Brand new install so last thought was the patch cables. But this turned out to be an easy one. Bad patch cable from Switch to Panel.
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