This PerfCounter64 counts Far End Severely Errored Seconds for a SONET/SDH Line in the history bin, meaning the remote node's line-layer SES count as reported back over the line overhead channel. Because the local end cannot directly see faults that only affect the far end's receiver, this far-end SES count lets an admin diagnose asymmetric problems, such as a laser degrading on the far transmitter, from the near-end management station alone. If ocnStmHistoryLineFarEndSESs is elevated while the corresponding near-end SESs stays near zero, the admin knows to investigate the transmit optics or fiber path leading toward the far-end node rather than the local receiver.