Safe combinations of services using B

The paper reports on the use of the B method and related tools to handle the feature interaction problem in telecommunications. The feature interaction problem states critical questions with respect to safety, sociological and legal aspects. Our approach proposes a new way to combine abstract machines and evaluates the resulting generation of proof obligations. The B method is a framework for specifying, refining and developing systems in a mathematical and rigorous, but simple way, and services are specified in the B method. The feature interaction problem is modelled simply as a violation of an invariant. The B method is supported by sofware that helps the specifier of services and features. We have not only modeled services within the B technology, but we have also extended possibilities of B by combining abstract machines.