This field records how much the counter for FCoE payload bytes transmitted out this same converged Ethernet uplink toward the fabric increased during the most recent collection interval, rather than the lifetime cumulative total. For a network admin, comparing this against bytesRx on the same interface shows whether the FCoE conversation is asymmetric, e.g. a host mostly reading from a SAN-attached LUN. For example, a value of 381,962 bytes would mean that much FCoE data crossed this uplink in just the last collection interval.