The Web Services Resource Framework in a Peer-to-Peer context

While Peer-To-Peer technologies can offer Grid computing increased scalability and inclusivity, they do not typically engage in the kind of complex interactions often required by the Grid in which context, or state, needs to be maintained across multiple service interactions. The Web Services Resource Framework is a relatively new specification that addresses the issue of handling resources with state in service-oriented architectures. While the specification makes a distinction between services and stateful resources, it still retains a coupling between a service address and a resource exposed by it. This coupling can be a hinderance in Peer-To-Peer networks where nodes may join and leave frequently and addresses may change or not be directly accessible. Furthermore it can undermine the loose coupling advocated by service-orientation. In this paper we assess the Web Services Resource Framework in the context of Peer-To-Peer environments and describe how WSPeer, a framework for hosting, discovering and invoking Web services, makes use of logical addressing, endpoint resolution and late-binding to maintain message consistency in such dynamic environments and de-couple services from stateful resources