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 cienaCesPmExtendedTxRxAllTimeBinRxLOutRangePkts. 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 '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 over-MTU frames in this bin; even 30 is enough to warrant a look, since this class of counter isn't supposed to move under normal operation.