This field reports the total number of packets received that were longer than 1518 octets but less than or equal to the MTU (excluding framing bits, but including FCS octets) and were otherwise well formed, exposed here as cienaCesPmExtendedTxRxStatsBinOversizePkts. On this Ciena CES port's PM data, these are frames longer than the standard 1518-octet limit but still within this port's configured MTU and otherwise well-formed, so this counter is expected to move if jumbo/tagged frames are provisioned on this port, and unexpected if they aren't; 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 valid oversized frames in this bin; even 0 is enough to warrant a look, since this class of counter isn't supposed to move under normal operation.