From Early Requirements to Business Processes with Service Level Agreements

When designing a service-based business process employing loosely-coupled services, one is not only interested in guaranteeing a certain flow of work, but also in how the work will be performed. This involves the consideration of non-functional properties which go from execution time, costs, up to security and trust. Ideally, a designer would like to have guarantees over the behavior of the services involved in the process. These guarantees are the object of Service Level Agreements. We propose a methodology to design service-based business processes together with service level agreements that guarantee a certain quality of execution, with particular emphasis on the security aspects. Starting from an early requirements analysis modeled in the SI* formalism, we provide a set of user-guided transformations and reasoning tools which final output is a set of processes, in the form of Secure BPELs, together with a set of service level agreements to be signed by participating services. To show the potential impact on security guarantees, we illustrate the functioning of the methodology on a e-business banking example inspired by an actual industrial case.