This field reports the number of in error packets received on the port, exposed here as cienaCesPmExtendedTxRxStatsBinRxInErrorPkts. On this Ciena CES port's PM data, these are frames the MAC accepted for delivery but flagged with a receive-side error (bad FCS, alignment, or a similar framing fault), so any nonzero movement here on an otherwise up link points at a cabling, optics, or upstream-device problem specific 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 in-error 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.