nested vlans and ethernet frame size

[Ivan Alexandrovich]

Thanks for all your replies and explanations.
Sure lowering mtu below 1500 bytes for all hosts or using
jumbo frames would be the right solution especially for
corporate network.

But we probably have to stick to 1500 bytes for one reason:
that FreeBSD-based router configuration I mentioned is for
segments where we use seperate vlan for each client
connection (we're an ISP): it seems that using anything
else instead of 1500 for clients will require too much tech
support efforts.

Since double-tagged frames will be transmitted only by one
ethernet link per segment (the link between upper level switch
with QinQ and FreeBSD router) then maybe it's acceptable
to allow a little deviation from the standard as long
as we remember the implications.

Thanks for the help
Ivan