Performance Annotated Business Processes in Service-oriented Architectures

This paper addresses quality of service aspects of orchestrated web service-based business processes in service-oriented architectures. The proposed mathematical model uses operations research techniques and formal semantics of the Business Process Execution Language for Web Services (BPEL4WS) to estimate expected execution times and counts of invocations of partner web services for each activity of a given process and for this process as a whole. These estimations are performed from the standpoint of a web service integrator. Furthermore, the model is applied to forecast the influence of the execution of a set of orchestrated processes on utilization and throughput of individual service provider nodes and of the performance of the whole system. The final objective is to support the optimization of service levels agreements (SLA) between the integrator and involved web service providers. A software infrastructure that implements the model is described as well.