The VLAN number of the VLAN that the
PVC is bound to.
Binding a PVC say with VCD number x,
to a VLAN with a VlanId y, causes the
traffic on VLAN y to pass through PVC x.
Also a PVC that is bound to a VLAN can
be unbound by the user. After the unbind
operation the VLAN traffic stops flowing
through the PVC. If the user changes the
value of this variable then the PVC is
unbound from the original VLAN and bound
to the new VLAN.