[j-nsp] Setting MTU in VPLS routing-instance on 8.5

[David Ball]

  Anyone know if it's possible to set the MTU in a VPLS
routing-instance in JunOS 8.5 (T-Series)?  I was able to do so for
L2Circuits, but don't see anything similar for VPLS.  The interface
MTU is 1600, but the LDP-signalled VPLS instance is advertising an MTU
of 1500, and in fact won't come up (with another vendor, whose MTU is
configurable per VPLS instance) unless the other vendor is set to
1500.  At very least, i'd like to know where it's coming up with the
1500, unless it's just a hard-coded default for VPLS.
  Any insight would be appreciated.

David