The vNET tag assigned to this VRF instance.
A value of zero(0) indicates the VRF instance is not a vNET and
such vrf could be part of a VRF-Lite or MPLS deployment.
A set with a value of zero(0) will remove the vNET tag assigned
to this VRF.
The value of this object can be changed even when
cvVrfRowStatus is having a value of active(1).