The VRF type of this interface. The type of the interface is
determined based on the VRF associated with this interface.
If the VRF is not tagged with vnet tag then the type will be
vrfEdge. If the VRF is tagged with vnet tag then it will become
vnetEdge. For vNETTrunkSI, the sub-interface in question is
automatically created for a VRF when trunking is enabled on the
main interface.