This read-only Counter64 counts messages the host-side logic discarded when a join or leave arrived on a port that has no established router port to forward toward. A climbing count on an access port means subscribers are trying to join multicast groups but the switch has no upstream path configured yet — a deployment gap rather than a subscriber fault; 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 an uplink toward the multicast-enabled core router, a count of 650 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.