This read-only Counter64 counts the total IGMP membership queries received on this PM instance. This is effectively a heartbeat count from the upstream multicast querier — it staying at zero for a whole bin is a first clue that no querier traffic is reaching this port; 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 residential VLAN used for multicast video delivery, a count of 2,170 over the 38 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.