This read-only CoriantTypesOtukFec value reports the FEC type used on the client OTUk signal for this OTU2 (about 10.7 Gbit/s) facility, defaulting to G709, applicable when the underlying port type is client or client-subport. FEC on the line-side OTU frame is what allows the transported signal to tolerate a certain level of optical impairment (like fiber-induced noise) over distance without becoming unrecoverable. For example, the OTU2 facility on slot 5 reading its default G709 FEC confirms it is using the standard OTN forward error correction defined for that OTUk rate rather than a vendor-specific enhanced FEC scheme.