This counter should be incremented when the number of routes
contained by the specified VRF exceeds or attempts to exceed
the maximum allowed value as indicated by
mplsL3VpnVrfMaxRouteThreshold.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
mplsL3VpnVrfPerfDiscTime.