A distributed execution environment for large-scale workflow management systems with subnets and server migration

If the number of users within a workflow management system (WFMS) increases, a central workflow server (WF-server) and a single local area network (LAN) may become overloaded. The approach presented in the paper describes an execution environment which is able to manage a growing number of users by adding new servers and subnets. The basic idea is to decompose processes into parts which are controlled by different WF-servers. That is, during the execution of a workflow instance its execution (step) control may migrate from one WF-server to another. By selecting the appropriate physical servers (for hosting the WF-servers) in the appropriate LANs, communication costs and individual WF-server workload can be reduced significantly.