This field reports the number of bytes transmitted per second on this PM instance, exposed here as cienaCesPmExtendedTxRxAllTimeBinTxBytesPerSec. On this Ciena CES port's PM data, this is a pre-computed rate gauge for the bin, giving you this port's transmitted-bandwidth directly without manually differencing two TxBytes polls; 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, polling this field mid-bin and seeing 72,300,000 bytes/sec transmitted tells you this port's live throughput right now, no extra math required.