The total number of frames of valid frame length
that have been received on the ports in this group
and for which the FCSError and CollisionEvent
signals were not asserted. This counter is the
summation of the values of the
rptrMonitorPortReadableFrames counters for all of
the ports in the group.
This statistic provides one of the parameters
necessary for obtaining the packet error rate.
The approximate minimum time for rollover of this
counter is 80 hours.