This read-only Counter64 counts bytes received on this PM instance that the switch discarded outright, rather than forwarding or yellow-marking them. This is the counter an admin escalates on — sustained non-zero drops mean traffic on this flow point exceeded even the excess-rate allowance or hit a policy/resource limit, and whatever service rides this instance will show real loss; because it is drawn from the lifetime bin, which keeps accumulating until an operator explicitly clears it, a sudden plateau on an otherwise busy instance is itself a signal — most likely that someone cleared the stats rather than that traffic actually stopped. On a 100 Mbps residential broadband EFP, this might read 455,000 bytes over the 178 days since the counters were last cleared — a number an admin would divide by the bin length to sanity-check it against the port's 100,000,000-bps ceiling.