This read-only Unsigned64 holds the raw count of aggregate transmit errors -- the overall count of errored frames this interface failed to send cleanly, rolling several lower-level transmit fault conditions into one number -- recorded in this one archived historical sample of an interface's error-statistics. This is the transmit-side counterpart to the receive-error rollup for this same interface, used as a first-pass check before looking at its deferred-transmission or internal-MAC-transmit detail. For example, a rise here on a port whose receive counters stay clean points the investigation specifically at this interface's transmit path rather than the far-end device.