Distributed Allocation of Workflow Tasks in MANETs

When multiple participants work on a workflow that represents a large, collaborative activity, it is important to have a well defined process to determine the portions of the workflow that each participant is responsible for executing. In this paper, we describe a process and related algorithms required to assign tasks in a workflow, to hosts that are willing to carry out the execution of these tasks, and thereby contributing to the completion of the activity. This problem is a stylized form of the multi-processor scheduling algorithm which has been shown to be NP-Hard. Further complicating the issue is that we are targeting our approach to mobile ad hoc networks, where hosts are physically mobile, communication links are frequently interrupted, and spatiotemporal considerations become increasingly important. We describe a distributed approach to task allocation in mobile ad hoc networks that employs heuristics to assign tasks in a workflow to mobile hosts based on their capabilities and their mobility patterns. We have implemented our algorithms in the context of CiAN, a workflow management system (WfMS) supporting collaborations in a mobile environment. In addition, we also present performance data of our algorithm and compare it to naive and brute force approaches