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 most recently completed 24-hour bin, frozen once the day rolled over, it is frozen and safe to use for day-over-day comparison, since no further traffic will ever be added to it. On a subscriber-facing IPTV access port, a count of 1,172 over the last completed collection window 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.