This read-only Counter64 counts IGMP packets received with an invalid IP checksum. Checksum failures point to link-layer corruption or a failing NIC/cable upstream of this port rather than a protocol issue, so admins treat a rising count here as a physical-layer lead; 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 subscriber-facing IPTV access port, a count of 2,634 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.