Total number of interfaces connected to this VRF with
ifOperStatus = up(1).
This value should increase when an interface is associated
with the corresponding VRF and its corresponding ifOperStatus
is equal to up(1). If an interface is associated whose
ifOperStatus is not up(1), then the value is not incremented
until such time as it transitions to this state.
This value should be decremented when an interface is
disassociated with a VRF or the corresponding ifOperStatus
transitions out of the up(1) state to any other state.