Enhancing control of service compositions in service-oriented architectures

In a service-oriented architecture, service compositions are assembled from other component services. Such compositions may include services from unknown and potentially untrusted providers. As there is no direct control of those services, it is not ensured that pre-negotiated policies are actually enforced as specified. In this work, we propose a pluggable component for controlling interactions of service compositions which we call Orchestration Service. It executes arbitrary service compositions on behalf of others and intercepts messages exchanged between the involved services. Thus, the Orchestration Service can ensure a correct enforcement of the stipulated policies. Moreover, it also monitors obligation statements and logs all interactions in an audit compliant way. Using this approach, the control over existing service compositions can be enhanced with little effort. We present the concept of the Orchestration Service, describe its usage and discuss which applications can be supported by our approach.