How to Check Port Flapping

[kaleemullahbilal1]

Dear All,

We are having 4500 Cisco Core Sw. It seems some of the Uplinks are flapping and i dont exaclty know where its happening.

can someone help how to troubleshoot this issue,

[Leo Laohoo]

In Catalyst 4k platform, the default settings for port configurations is "NO logging event link status".  Is this the case?

[Georg Pauwen]

Hello,

what is connected to these uplink ports ?

[kaleemullahbilal1]

Server Switches, HX etc

[Georg Pauwen]

Hello,

the reason I am asking is that the problem can also be the connected device(s), rather than the Cisco 4500. What do the logs on both devices (if the logs are available) show ?

[MHM Cisco World]

under each interface not in global mode.
450x(config-if)#logging event ?

link-status UPDOWN and CHANGE messages<-

[kaleemullahbilal1]

can i run this command in Live environment ..wont be any memory utilization issue..

[paul driver]

Hello

Are this uplinks trunk or access ports?
sh spanning-tree int x/x detail | in transitions
sh int | inc L2|line|broadcast
sh int | in line|\/sec
sh int x/x counters

[kaleemullahbilal1]

These are uplinks, can you be more specific about the commands..

[Leo Laohoo]

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@kaleemullahbilal1 wrote:

These are uplinks, can you be more specific about the commands..

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Post the configuration of the interface in question. 

If the command "logging event link-status" is not in the configuration of the interface this means flapping link ports are not visible in the logs (the command "NO logging event link-status" is hidden, by default).

[Mark Elsen]

            - Check the logs on the 4500 for more info.

 M.