The cumulative number of station-learning frames generated
due to UplinkFast transitions. All generated
station-learning frames are included in this counter,
irrespective of the instance of the Spanning Tree Protocol
on which the UplinkFast transition occurred.
If the platform supports the stpxUplinkFastOperEnabled
object, then this object is not instantiated when the
object value of stpxUplinkFastOperEnabled is false(2).
If the platform does not support the
stpxUplinkFastOperEnabled object, then this object is
not instantiated when the object value of
stpxSpanningTreeType is mst(4).