This field reports the number of bytes forwarded on this PM instance, exposed here as cienaCesPmBasicTxRxHistoryBinTxForwardedBytes. On this Ciena CES port's PM data, this counts bytes that actually made it out this port after every policing and queuing decision was applied, i.e. the delivered side of the bandwidth profile rather than the raw ingress figure; and this lives in the basic bandwidth-profile-aware PM group's history bin — a closed-out interval whose own Duration and State tell you how long it ran and whether it closed cleanly, so the number is settled rather than still being written to. For example, a moderately busy port showing 23,100,000 forwarded bytes for this bin would be a plausible, unremarkable reading.