This attribute counts the number of DPRS packets received from the
remote module that have been discarded by the Trunk. It is an array
indexed by the emission priorities (ep0, ep1 and ep2) and discard
priorities (dp0, dp1, dp2 and dp3) of the packets. The highest
emission priority is ep0 and the least discardable priority is dp0.
These counters wrap around to zero when the maximum value is
exceeded.