[c-nsp] Same MAC addresses from two ports on different VLAN

[Jay Nakamura]

We have an Extreme Summit switch where I found that if you have two
separate ports on different VLANs, and the same MAC address enters the
switch on those two completely different VLANs, the switch will start
having problems forwarding traffic.  (Or only use the first entry in
the FDB, I am not sure what it actually does other than half of the
traffic drops.)  Extreme support has confirmed that this is by design.

The reason I am posting this here is simple, does Cisco switches do
the same thing?  Or if MAC address comes from two ports on different
VLAN, would it just forward per VLAN?  Or would it depend on the
model?

I can think of so many possible problems with this that I want to see
if this is common design of switches or just Extreme and I need to
start using different L2 switches.

Thanks