This field reports the number of excessive defer packets transmitted on the interface, exposed here as cienaCesPmExtendedTxRxStatsBinTxExDeferPkts. On this Ciena CES port's PM data, this is a step up from ordinary TxDeferPkts — it only increments when a frame was deferred so long, because the shared medium stayed continuously busy, that it crossed Ciena's excessive-defer threshold, which points at a badly congested half-duplex or shared segment rather than routine CSMA/CD backoff; 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 excessively-deferred 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.