: The specification of the dynamic behaviour of reactive distributed systems must exhibit the structures of control and has to imply explicitly the relevant aspects of the distribution, such as the concurrency, the reactivity and the interaction between the entities. Among the most common reactive distributed systems we can cite industrial ones; distributed networks occur for example in telecommunications, Internet, power and energy, transportation and manufacturing. Distributed computing will play an increasingly critical role in the global industrial-infrastructure. The need for trustworthy systems has received tremendous researchers’ attention. The usage of formal tools for simulation and prototyping designed to facilitate the modelling of such systems is of great interest. Improved methods are needed to insure reliability, security and robustness of industrial distributed systems. This paper proposes the fundamentals of a formal approach for the specification of reactive distribu...