Error detection EDC= Error Detection and Correction bits (redundancy) D = Data protected by error checking may include header fields Error detection not 100% reliable! protocol may miss some errors, but rarely larger edc field yields better detection and correction datagram datagram a bits in D N ○K detected ? error ← d data bits D EDC D EDC o bit-error prone link 0 5: DataLink Layer 5a-75: DataLink Layer 5a-7 Error Detection EDC= Error Detection and Correction bits (redundancy) D = Data protected by error checking, may include header fields • Error detection not 100% reliable! • protocol may miss some errors, but rarely • larger EDC field yields better detection and correction