Safe orchestrated multicomposition of systems of communicating finite state machines

The Participants-as-Interfaces (PaI) approach to system composition suggests that participants in a system can be considered interfaces to the outside world. Given a set of systems, one participant per system is chosen to play the role of an interface. When systems are composed, these interface participants are replaced by gateways that communicate with each other by forwarding messages. The PaI approach for systems of asynchronously communicating finite state machines (CFSMs) has been exploited in the literature for binary composition where the forwarding policy is necessarily unique. In this paper we consider the case of multiple system composition and extend preliminary work to the case where interactions among gateways can be mediated by additional orchestrating participants that comply with a given connection model. We represent the interactions among gateways as CFSM systems (called orchestrated connection policies) and prove that a number of relevant communication properties (e.g. deadlock-freedom, reception-error-freedom) are preserved by orchestrated PaI multicomposition, provided that the orchestrated connection policy used also satisfies the communication property in question.