Protocol

The set of rules agreed for the transfer of information between computer systems. Protocols are vital elements in computer networks with different host systems.

Protocols are defined at different layers. High-level protocols may concern software for job submission or filing systems, low-level protocols concern transfers of small packets of information or even characters, independent of the information content; lowest-level protocols determine the hardware interfaces.

A good protocol includes the addition of error-detecting and even error-correcting information, e.g. cyclic redundancy checks (CRCs).

For more reading, see McNamara82.