1. An optical transport network (OTN) apparatus comprising: an Optical channel Transport Unit (OTUk) frame generator to generate OTUk frames; a Forward Error Correction (FEC) encoder device, operatively coupled to receive and apply FEC encoding to data from the OTUk frames; and a row de-interleaver device operatively coupled to the FEC encoder device to apply, to encoded data from the FEC encoder device, multiple permutation operations in respective different dimensions.