Verifying communication constraints in RSML specifications

Discusses a formal approach to the specification of inter-component communication in RSML (Requirements State Machine Language) specifications. The approach is based on communicating finite state machines. The formalism allows the encapsulation of communication-related properties in well-defined interface specifications. The encapsulation enables us to use the interface specifications as simple safety kernels and to enforce certain safety and liveness constraints in these kernels, Furthermore, we describe how safety and liveness constraints related to inter-component communication can be formalized using a simple and easy-to-understand constraint language. To formally verify that the constraints are satisfied in an RSML model, we attempt to prove that the constraints are satisfied by only looking at the interface specifications. We illustrate the approach with an example from the TCAS II (Traffic Collision Avoidance System) avionics system.