This field reports the total number of packets received that were longer than the MTU (excluding framing bits, but including FCS octets) and were otherwise well formed, exposed here as cienaCesPmExtendedTxRxStatsBinRxLOutRangePkts. On this Ciena CES port's PM data, these are frames that arrived well-formed (good FCS) but longer than this port's configured MTU, so they weren't corrupted in transit — they simply exceed what this interface is currently willing to accept, which typically means either the far end's MTU/jumbo setting doesn't match this port's, or someone is sending frames sized for a jumbo-enabled path that hasn't actually been provisioned here; 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 over-MTU frames in this bin; even 2 is enough to warrant a look, since this class of counter isn't supposed to move under normal operation.