This field reports the cumulative count of frame transmission errors recorded for this network interface, tracked by this particular stats object since it was created or last reset. For a network admin, this tracks failures on the send path specifically, so pairing it with the interface's CRC (receive-side) counter tells an admin whether a problem is local to this card's transmitter or is coming in from the far end. For example, a cumulative value of 37 frame transmission errors since the interface came up would still be within a tolerable range, whereas a rapidly climbing count in the hundreds would justify escalation.