Mac flapping between port-channel ports

[danielesquaranti]

Good Morning,

I have a problem with a couple of  Cisco Switches 3850 which have the distribution function.

I found these in the log section:

Jul 16 10:24:04 switch-dist 41042: .Jul 16 08:26:24.625: %SW_MATM-4-MACFLAP_NOTIF: Host 4e9a.19da.402a in vlan 2 is flapping between port Po2 and port Po3 

The Port-channels are connected to the access switches.

From my analysis it seems that the problem occurs when a pc connects from one floor to another (therefore most likely from one AP to another), most likely because the access points are not positioned correctly.

the spanning-tree doesn't seem to give any problems..

Does anyone know if there is any setting / configuration that could fix it?

Thanks in advance

[Octavian Szolga]

Hi,

That's a normal behaviour. If your APs are connected to two different access switches and your laptop is roaming from one AP to another and traffic is placed directly over wire by APs, then it's normal.

BR,

Octavian

[Leo Laohoo]

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@danielesquaranti wrote:

Jul 16 10:24:04 switch-dist 41042: .Jul 16 08:26:24.625: %SW_MATM-4-MACFLAP_NOTIF: Host 4e9a.19da.402a in vlan 2 is flapping between port Po2 and port Po3 

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What is this MAC address?  The OUI does not match anything. 

Trace this client all the way down to the port.  From the switch, check how many uplinks and compare the etherchannel.  MAC address flapping is always caused by multiple uplinks not in an etherchannel.

[Mohsin Alam]

If the mac is of wireless device and caused when they are roaming it's completely expected.

You can use logging discriminator to suppress the logs.

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