A decentralized execution model for inter-organizational workflows

Workflow Management Systems (WFMS) are often used to support the automated execution of business processes. In today's networked environment, it is not uncommon for organizations representing different business partners to collaborate for providing value-added services and products. As such, workflows representing the business processes in this loosely-coupled, dynamic and ad hoc coalition environment tend to span across the organizational boundaries. As a result, it is not viable to employ a single centralized WFMS to control the execution of the inter-organizational workflow due to limited scalability, availability and performance. To this end, in this paper, we present a decentralized workflow model, where inter-task dependencies are enforced without requiring to have a centralized WFMS. In our model, a workflow is divided into partitions called self-describing workflows, and handled by a light weight workflow management component, called the workflow stub, located at each organization. We present a performance study by considering different types of workflows with varying degrees of parallelism. Our performance results indicate that decentralized workflow management indeed enjoys significant gain in performance over its centralized counterpart in cases where there is less parallelism.