This field reports the number of late collision packets transmitted on the interface, exposed here as cienaCesPmExtendedTxRxStatsBinTxLateCollPkts. On this Ciena CES port's PM data, a late collision is detected after the normal slot time has already passed, the textbook symptom of a duplex mismatch (one end full-duplex, the other half) or an oversized shared segment attached to this port; and this sits in the currently active extended Tx/Rx interval bin — its sibling StartTime/ClearTime fields mark exactly which window is being counted, so a change here reflects activity happening in the live collection interval, not something already filed away in history. For example, a healthy port would sit at 0 for late-collision frames in this bin; even 1 is enough to warrant a look, since this class of counter isn't supposed to move under normal operation.