A communication system is described, among other things. An illustrative system is disclosed to include one or more decoding circuits to perform forward error correction for a received data block in a physical layer and one or more cyclic redundancy check circuits to perform a cyclic redundancy check based on a first output of the decoding circuits and a cyclic redundancy check code generated in the physical layer based on the received data block. In response to one or more of a second output of the decoding circuits and an output of the cyclic redundancy check circuits, a retransmission request of the data block is initiated.