A client-server protocol the composition of petri nets

Abstract

Modelling the behavior of a system as a set of cooperating nets requires to define a high-level communication protocol which takes into account the very nature of their interactions. This paper proposes to adapt the client-server protocol promoted by the object-oriented approach to Petri nets, and to compose Petri nets according to this protocol. This protocol relies upon four basic rules which assert the honesty and discretion of clients and servers. A class of nets respecting these rules, called clientserver nets, is defined, as is the composition of these nets according to a Use function. The possibility to compose client-server nets while preserving the nets' language and liveness is studied. This possibility comes down to very simple relationships between the main characteristics of client-server nets: the demand and the confidence degree as a client, and the supply and the reliability degree as a server. These relationships are preserved by the composition of nets, so the client-server protocol allows for the incremental design of systems and favors the reuse of nets.