[c-nsp] dot1q-tunneling

[sthaug at nethelp.no]

> Been a while since I worked with Extreme switches.. 
> 
> If Cisco is doing Q-in-Q then Extreme is droping frames. Extreme does not expect Q-IN-Q with 0x8100 ethertype. It is a sort of security feature to prevent VLAN hopping, but check with Extreme gurus...

Actually some newer Extreme switches will handle an outer VLAN tag
with an Ethertype of your choice, so for instance (8100, 8100) is
perfectly possible. We have several Summit 450 configured this way.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no