A peer to peer (P2P) architecture for dynamic workflow management

This paper presents the architecture of a novel Peer to Peer (P2P) workflow management system. The proposed P2P architecture is based on concepts such as a Web Workflow Peers Directory (WWPD) and Web Workflow Peer (WWP). The WWPD is an active directory system that maintains a list of all peers (WWPs) that are available to participate in Web workflow processes. Similar to P2P systems such as Napster and Gnutella, it allows peers to register with the system and offer their services and resources to other peers over the Internet. Furthermore, the architecture supports a novel notification mechanism to facilitate distributed workflow administration and management. Employing P2P principles can potentially simplify the workflow process and provide a more open, scalable process model that is shared by all workflow participants. This would enable for example a WWP to connect directly to another without going through an intermediary, currently represented by the workflow process management server. P2P workflow becomes more efficient as the number of peers performing the same role increases. Available peers can be discovered dynamically from the WWPD. The few currently existing P2P based workflow systems fail to utilise state of the art Web technologies such as Web Services. In contrast, using the approach described here it is possible to expose interoperable workflow processes over the Internet as services. A medical consultation case study is used to demonstrate the proposed system. q 2003 Elsevier B.V. All rights reserved.