[c-nsp] Cisco catalyst switch stop learning MAC address

[Arun Kumar]

Hi,

I faced a strange issue in our network. The network consists of multiple
Cisco switches connected and running MSTP. NPEG2 router is connected to a
switch port. The router interface MAC address was flapping in the L2 switch
network. The issue was sorted out and mac flap was stopped. But after this
, MAC address of the router's interface stopped learning on the connected
Cisco switch. Only when the interface on the router was shut and no shut,
the switch started learning MAC address.

Does anyone faced this kind of issue? What could have made the cisco switch
to stop learning  MAC address from the connected router?

thanks in advance
Arun