Specification and Execution of Policies for Grid Service Selection

We show how a standard Grid service architecture can be improved by interposing a policy enforcement engine between a calling application and the relative client stubs. Therefore, with our solution selection and invocations are not hard-coded into client applications but (declaratively) defined and enforced outside the clients; therefore they can be (de)activated and modified on-line. Our policies are specified using the PDL language which supports specification of preferences and prohibitions in the routing of remote invocations to Web services