Interaction protocols and capabilities: A preliminary report

Abstract. A typical problem of the research area on Service-oriented Architectures is the composition of a set of existing services with the aim of executing a complex task. The selection and composition of the services are based on a description of the services themselves and it often exploits an abstract description of the system that we wish to build. A distinction is made between the global and the individual points of view of the interaction between the services. Interaction protocols (or choreographies) capture the interaction as a whole, defining the rules that entities should respect in order to guarantee the interoperability; they do not refer to specific services but they specify the roles and the communication among the roles. Policies (behavioral interfaces in web service terminology), instead, focus on communication from the point of view of the individual services. We can find many works that aim at verifying if a service can take part in a specific interaction, that is if its behavioral interface is conformant to the global protocol. The idea of focussing o