A Theory for Protocol Validation

This paper introduces a simple algebra for the validation of communication protocols in message passing systems. The behavior of each process participating in a communication is first modeled in a finite state machine. The symbol sequences that can be accepted by these machines are then expressed in "protocol expressions," which are defined as regular expressions extended with two new operators: division and multiplication. The interactions of the machines can be analyzed by combining protocol expressions via multiplication and algebraically manipulating the terms.