%MAC_MOVE-SP-4-NOTIF: Host (mac address) in vlan x is flapping between port Po2 and port Po20

Unanswered Question
Sep 24th, 2010

We keep getting constant errors on our syslog and wism having this error.  We've figured that it was wireless clients transitioning to different WLC, but now we've moved all of our APs onto the same controllers per building with the same errors.  Wireless clients are not migrating to different buildings, but we are still getting the errors.  Most of the clients are voip phones and vocera badges.  I'm not seeing any bugs on version relating to this, any ideas?

I have this problem too.
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Nicolas Darchis Thu, 10/07/2010 - 09:21


I don't think it's a bug. What is behind those 2 port channels ?

Do you see the client entry on the other WLCs ?


Mark Combs Thu, 11/11/2010 - 22:52

Bascially the MAC address is being seen on two different port-channels which is the cause for the flapping.  You need to track down the MAC of the host that is flapping between ports and investigate.  Issues could be NIC teaming issues.  For example, I have seen issues where specific blade chassis that contain one more switches are split among a pair distro switches.  Those then connect to a pair of core switches.  If the the NIC teaming is set incorrectly on the server then the mac might show up via different paths to the root bridge.  Might be the cause for the flapping.

Start with the host and work your way backward through the network.

Good Luck

- Mark


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