[c-nsp] Layer 2 question

[Mike Johnson]

What happens if a layer 2 switch receives a frame that needs to be forwarded
out the same
port that the incoming frame was received on?

Im realize that a typical layer 2 switch would never forward that packet
upstream in the first place.
However, If it did in fact happen what does the upstream L2 switch do?

I have a situation that a non standard layer 2 device may in fact do what I
described above.

mike