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New Member

Catalyst fast ethernet ports going up & down

We have 11 catalyst switches, 3548s and 3524s.

I have turned on logging at the warning level.

I checked the logs the next morning and found a whole bunch of entries like the following:

2002-11-12,06:46:04,xxx.xxx.xxx.xxx,23,3,9687: 8w6d: %LINK-3-UPDOWN: Interface FastEthernet0/25, changed state to up

2002-11-12,06:46:23,xxx.xxx.xxx.xxx,23,3,9688: 8w6d: %LINK-3-UPDOWN: Interface FastEthernet0/25, changed state to down

2002-11-12,06:46:24,xxx.xxx.xxx.xxx,23,3,9689: 8w6d: %LINK-3-UPDOWN: Interface FastEthernet0/25, changed state to up

2002-11-12,06:46:26,xxx.xxx.xxx.xxx,23,3,9690: 8w6d: %LINK-3-UPDOWN: Interface FastEthernet0/25, changed state to down

The most I can find on Cisco's tech support is that the interfaces are going up and down, which doesn't help much.

Any thoughts on just what might be causing this on so many ports and on multiple switches? Our network is a flat layer 2 network with approximately 200 nodes (layer 3 is coming soon), running ip only.

These port "flappings" also show up on the single 3524 on our external (internet) lan and our dmz lan.

Since the odds of multiple nodes all having netcard problems is unlikely, I am wondering if broadcasts might be a possible culprit.

Thanks.

1 REPLY
New Member

Re: Catalyst fast ethernet ports going up & down

The problem is probably with autonegociation. Try to fix the port speed. I received a lot this message with catalyst 3524 PWR.

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