This counts the total number of packets dropped for any reason. As the aggregate of every specific drop-reason counter in this MIB, such as TTL expired, bad header, no route, multicast disabled, filtered, no ARP entry, bad buffer length, and bad IP version, this is the first number an admin checks to know whether drops are happening at all, before breaking it down by the more specific counters to find the actual cause. A sudden spike in this total counter would prompt an admin to check each of the specific dropped-packet counters individually, TTL expiry, no-route, bad-header, and the rest, to isolate which particular failure mode is actually responsible for the spike.