[c-nsp] H-VPLS/P2MP style functionality with L2TPv3 inside VFI

[James Bensley]

Hi Arie, Spros,

Yeah L2TPv3 isn't support on ME3600, I just mentioned those devices
becasue they are knocking around in the lab.There are ASRs in there
two so I will try labbing this with an ASR1K.

Cheers,
James.