Towards A Flexible Mediation Framework for Dynamic Service Invocations

One of the main benefits of service-based systems is the loose coupling of components, which allows for flexibility in the selection of internal and external business partners. However, currently this flexibility is severely limited by the fact that components have to provide not only the same functionality, but do so via virtually the same interface. Invocation-level mediation may be used to overcome this issue – using mediation interface differences can be resolved transparently at runtime. In this paper we present the general concepts of invocation-level mediation, and show how these ideas are integrated in our dynamic service invocation framework DAIOS. To demonstrate the flexibility of our mediation framework we have implemented two fundamentally different mediation strategies, one based on structural similarity and one based on semantically annotated WSDL (SAWSDL). We evaluate the runtime performance of our mediation strategies, compare them with unmediated invocations and relate the overhead introduced by invocation mediation to the flexibility gained by this approach.