This read-only counter tracks the number of transmit frames on the Ethernet interface that experienced a late collision, meaning the collision was detected more than 512 bits into the frame. An admin treats this as a serious diagnostic signal, since late collisions typically point to a cabling problem or a duplex mismatch rather than normal contention. A rising statIflanEthLateCollision count would lead an admin to check for a duplex setting mismatch between the interface and its link partner.