The PowerRouter v3 has a 8 port GigE Modle
All the ports on that module show no l2mtu / max mtu
It's greyed out.
If I set the mtu higher than 1500, i'm changing the ip mtu on that interface, so if I set it to 9000 i'd have to set the mtu on the opposite interface to 9000.
So I don't see how I could have
IP MTU =1500
MPLS MTU = 1512 at minimum
L2 MTU = MPLS MTU + 4
Sorry, i'm just a bit confused and kind of angry the PowerRouter module doesn't report the l2mtu, that would be much easier.