This Gauge counts Far End Errored Seconds — errors reported back by the remote end via FEBE indications — accumulated at the Line layer during the current 15-minute interval, reflecting problems the far end is experiencing receiving from this device rather than problems this device sees receiving from the far end. An admin cares because a rising Far-End ES count with a clean local (near-end) ES count means this device's transmit path or the far end's receiver is the problem, not this device's own receiver. For example, far-end ES climbing while local ES stays at zero points troubleshooting toward this device's transmitter or the fiber run in the outbound direction.