From what I read about MTU needed for MPLS/VPLS, the RB450G l2mtu at 1520 cannot do MPLS + VPLS without fragmentation is that correct ?
> /int pr
Flags: D - dynamic, X - disabled, R - running, S - slave
# NAME TYPE MTU L2MTU MAX-L2MTU
0 R ;;; Uplink
ether1 ether 1500 1520 1520