This read-only Counter64 counts IGMP packets dropped because the switch ran out of internal resources to process them. This is the counter that shows real control-plane overload — sustained increases mean the incoming IGMP message rate on this instance is outrunning the snooping/proxy engine's capacity, the first symptom of an IGMP flood; 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 subscriber-facing IPTV access port, a count of 3,454 over the 52 days since the counters were last cleared is the kind of number an admin would trend against the join/leave rate on the same port to judge whether it's normal channel-surfing or an anomaly worth a closer look.