Attached devices not listed in MAC address table - Page 2

johnoliphant1 · ‎03-24-2015

Yesterday I attached three SiriusXM radios to a stack of 3750s. The radios were/are working great, on ports Gi5/0/24, 27, and 29.

This morning I have a bunch of errors filling the log:

Mar 24 08:13:34.198: %SW_MATM-4-MACFLAP_NOTIF: Host 76c2.5e30.1599 in vlan 110 is flapping between port Gi5/0/24 and port Gi5/0/29

Mar 24 08:13:54.842: %SW_MATM-4-MACFLAP_NOTIF: Host 76c2.5e30.1599 in vlan 110 is flapping between port Gi5/0/27 and port Gi5/0/24

Mar 24 08:14:24.318: %SW_MATM-4-MACFLAP_NOTIF: Host 76c2.5e30.1599 in vlan 110 is flapping between port Gi5/0/24 and port Gi5/0/27

I can find the offending MAC in the address-table at Gi5/0/24, but the others are not in the table. Unfortunately, the devices won't give up their MACs in the device menus or on any labels.

So I'm confused....how can they be working, transmitting and receiving, yet no MAC in the address table?

-John

johnoliphant1 · ‎04-06-2015

We can close this one as solved....it turns out that two of the devices have identical MAC addresses.

Short term, we put them on separate vlans. Long term, we're getting the manufacturer to replace one of them.

Thanks for all your help!

Charles Hill · ‎04-06-2015

Thanks for the update.

rakeshvelagala · ‎03-25-2015

Hi Jon,

Yes I agree my bad.

johnoliphant1 · ‎03-25-2015

So close... :)

PHS_3750X-MDF#clear mac address-table
% Incomplete command.

Charles Hill · ‎03-25-2015

Did you try clear mac address-table dynamic?

johnoliphant1 · ‎03-25-2015

I just tried it. Still only one of the interfaces in the list. :(

FWIW the radios are working great since yesterday, streaming SiriusXM music. Actually, I think it's not really a stream, but bursts.

rakeshvelagala · ‎03-25-2015

Hi Can you please post below output

sh mac address table for vlan 110

If possible, connect all the three of them to a different switch (Standalone) and check if you see same issue.This will eliminate the error because of stack switches.

johnoliphant1 · ‎03-25-2015

Here's the command output. I had these radios running on another switch for a week or so, and that log doesn't show any problems.