Supporting Service-Oriented Design with Metrics

The service-oriented architectural style is widely perceived today. However, service orientation is a very general concept and its application in real-life situations is somewhat ambiguous. This is partially due to the fact that service-oriented principles are subject to interpretation rather than elements of the style.In this paper we propose a set of design metrics for service-oriented design. Based on an established metric for the coupling of component-based systems we introduce a complexity metric by the means of service coupling. We argue that service aggregators and the centralization of a system's control flow is appropriate to address a system's complexity. In order to approach an objective design that incorporates these principles, we introduce four metrics for the analysis of how a system handles its complexity with service-oriented means. Finally, we apply the presented metrics to an enterprise-scale real-life case study that we have conducted.