Lan issue - something bringing down switch

Unanswered Question
Apr 26th, 2009

Hi all, I have a network, with 5 switches, in the warehouse there are 6 cisco access points configured for roaming. every few hours the users in the warehouse are getting kicked out of there remote terminals, when this happens i notice that the ping times to the switch go to 600ms, where the other switches are ok. when they reboot the switch, all is then ok again.


Any ideas what could be causing this ?


cheers


Carl

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scottmac Sun, 04/26/2009 - 14:14

Check your switch logs to see if you have messages indicating MAC flapping or similar.


Some combinations of AP and switch (usually a non-Cisco AP) cause this because the AP handling the departure of a user isn't handing off to the arriving AP in a clean fashion, and the switch sees the same MAC coming from two different ports.


Update all your firmware, especially the AP. I have heard this happening mostly with Symbol APs and older Cisco switches.


Good Luck

Scott

carl_townshend Mon, 04/27/2009 - 00:39

Hi


I have done a packet capture last night, it seems as the switch is multicasting on 239.255.62.72 and it does this for a long time,I think this could be bringing the switch down.


any ideas what this is ?

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