This read-only Counter64, described simply as the total number of octets transmitted on this port during the bin, appears to be a running or aggregate variant alongside cienaCesPmExtendedTxRxHistoryBinTxBytes, distinguished by the extra 'T' in its name suggesting a cumulative total rather than a strictly per-bin figure. Because the MIB defines both a TxBytes and a TxTBytes field with near-identical wording, an engineer working with this table should verify empirically, or against Ciena documentation, exactly how the two differ in practice, for instance whether one includes framing overhead the other excludes, rather than assuming they're redundant. An engineer building automated PM parsing would flag this field specifically for validation against a known traffic generator test to confirm its exact semantics relative to TxBytes before relying on it in a report.