This field reports the number of late collision packets transmitted on the interface, exposed here as cienaCesPmExtendedTxRxAllTimeBinTxLateCollPkts. 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 'all-time' counter for the extended Tx/Rx PM group has no fixed rollover schedule of its own — it just keeps accumulating from whenever the PM instance was last cleared, so a single reading only tells you the running total, not a rate. For example, a healthy port would sit at 0 for late-collision frames in this bin; even 27 is enough to warrant a look, since this class of counter isn't supposed to move under normal operation.