A MAC unit processes the flow of data a first processor and a physical-layer control unit of a network component. The first processor processes the data flow between a higher protocol-layer unit and the MAC and assigns connection identifiers to each outgoing MAC protocol-data unit. The MAC unit includes a connection port adapted to couple to the first processor and a second processor that receives outgoing MAC protocol-data units generated by the first processor and generates outgoing FEC blocks therefrom for outputting to the input port of the physical-layer control unit. The second processor having an output port to provide outgoing FEC blocks to the physical-layer control unit and an input port to receive incoming FEC blocks from the physical-layer control unit. The second processor is adapted to generate incoming MAC protocol-data units from incoming FEC blocks received at its input port and to output them on the connection port.