This field reports the number of bytes received per second on this PM instance, exposed here as cienaCesPmExtendedTxRxAllTimeBinRxBytesPerSec. On this Ciena CES port's PM data, this is a pre-computed rate gauge for the bin rather than a running total, letting you read this port's received-bandwidth directly without manually differencing two RxBytes polls and dividing by elapsed time yourself; 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 463,000 bytes/sec received tells you this port's live throughput right now, no extra math required.