This is the 64-bit High Capacity version of the inbound packet counter, existing specifically because the 32-bit cnpdAllStatsInPkts counter can wrap around to zero in a matter of hours or minutes on a very high-throughput interface. Polling this 64-bit object instead avoids the false traffic-dropped-then-spiked readings that a wrapped 32-bit counter would otherwise produce in monitoring graphs. On a 10 Gbps interface carrying heavy protocol traffic, an NMS should poll this HC counter rather than the plain one to get an accurate, non-wrapping trend line.