Abstract: Systems and methods are disclosed for modulating, with circuitry of a source node in a communication network, at least one optical carrier to carry data utilizing a format of a soft decision forward error correction (SD-FEC) data field of an overhead portion of a data frame; encoding, with the circuitry of the source node, first data being SD-FEC data and second data being additional data into the SD-FEC data field, the first and second data being accessible without accessing client data traffic; and transmitting, with the circuitry of the source node, the data frame including the soft decision forward error correction data field. In one implementation, the second data comprises automatic protection switching bytes.