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 this table's currently-accumulating, short-interval bin, it reflects only the last few minutes of activity, so it's the value to watch for a fast-forming problem rather than a long-term trend. On a metro aggregation uplink carrying several video EVCs, a count of 1,072 over the last 15 minutes 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.