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New Member

Link-Flaps

I have a Catalyst 2950. Client computers on this switch have been working fine for quite some time now but recently I have had 2 computers go into an error disable state. I can assume it is because the port detected a "link-flap" on the port since this is a simple access port with spanning-tree portfast. There is not really any detail on why the port err-disables. I can simply enable the recovery of the flap, but is that really sloving the problem of why these ports are all of a sudden err disabling? Any tips on how I can dig down into this error to find the cause? Some more defined logging?

Thanks,

Sigh

4 REPLIES
Cisco Employee

Re: Link-Flaps

Each time a port is put into err-disable, the switch would log a message indicating why. If it was due to link-flap, check for any NIC/cable issues.

You can also enable automatic recovery

CAT2950(config)#errdisable recovery interval ?

<30-86400> timer-interval(sec)

CAT2950(config)#errdisable recovery cause ?

all Enable timer to recover from all causes

bpduguard Enable timer to recover from BPDU Guard error disable

state

channel-misconfig Enable timer to recover from channel misconfig disable

state

dhcp-rate-limit Enable timer to recover from dhcp-rate-limit error

disable state

dtp-flap Enable timer to recover from dtp-flap error disable state

gbic-invalid Enable timer to recover from invalid GBIC error disable

state

link-flap Enable timer to recover from link-flap error disable

state

loopback Enable timer to recover from loopback detected disable

state

pagp-flap Enable timer to recover from pagp-flap error disable

state

psecure-violation Enable timer to recover from psecure violation disable

state

security-violation Enable timer to recover from 802.1x violation disable

state

udld Enable timer to recover from udld error disable state

unicast-flood Enable timer to recover from unicast flood disable state

vmps Enable timer to recover from vmps shutdown error disable

state

New Member

Re: Link-Flaps

Can you tell me where I would see why the port went into an err-disable state? Do I have to enable more logging? All I can see is that the port went to administrativly down with "show logging"

Cisco Employee

Re: Link-Flaps

The message should be logged with default logging levels. You can also issue the following command.

CAT2950#sh interfaces status err-disabled

Port Name Status Reason

Fa0/1 err-disabled loopback

CAT2950#

New Member

Re: Link-Flaps

Great. Thanks. I will try that next time the int err-diasables on me.

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