This read-only Counter64 counts the total IGMP leave messages received on this PM instance. Comparing Leaves against Joins over the same bin shows whether multicast group membership on this port is growing or churning, which matters for capacity planning on a video-heavy access node; because it is drawn from the current, still-open 24-hour bin for today, the number keeps climbing until midnight rollover, so it should be read as "so far today" rather than a finished daily total. On a subscriber-facing IPTV access port, a count of 3,605 over today so far 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.