A transmitting device generates a nominally unguaranteed error-detection code for each sub-data packet of a data packet, and a nominally guaranteed error-detection code for the data packet. The transmitting device transmits to a receiving device the data packet including the sub-data packets thereof, the nominally guaranteed error detection codes for the sub-data packets, and the nominally guaranteed error-detection code for the data packet. For each sub-data packet, the receiving device uses the nominally unguaranteed error-detection code for each sub-data packet to determine whether the sub-data packet is erroneous. In response to determining that no sub-data packet is erroneous, the receiving device uses the nominally guaranteed error-detection code for the data packet to determine whether the data packet is erroneous.