On the interaction between checksums and cyclic redundancy codes in communications protocols

Cyclic redundancy codes are often used in communications protocols to detect and correct random bit errors that may occur due to noise in the channel. Checksums are also often used for a similar purpose, often within the same protocol stack. This paper examines the interaction between the use of CRCs and checksums in the ANSI C12.21 protocol and finds that the use of the checksum improves the net detection capability of 4-bit errors in 264-byte messages by two orders of magnitude.