Asynchronous peer-to-peer Web services and firewalls

In this paper we test the suitability of Java to implement a scalable Web Service that solves a set of problems related to peer-to-peer interactions between Web Services that are behind firewalls or not generally accessible. In particular we describe how to enable reliable and long running conversations through firewalls between Web Service peers that have no accessible network endpoints. Our solution is to implement in Java a Web services dispatcher (WSD) that is an intermediary service that forwards messages and can facilitate message exchanges by supporting SOAP RPC over HTTP and WS-addressing for asynchronous messaging. We describe how Web service clients that have no network endpoints, such as applets, can become Web Service peers by using an additional message store-and-forward service ("mailbox"). Then we conduct a set of experiments to evaluate performance of Java implementation in realistic Web Service scenarios, involving intercontinental tests between France and the US.