Stateful Interactions in Web Services: A Comparison of WS-Context and WS-ResourceFramework

Abstract

In July 2003 a consortium of Web Services vendors released the Web Services Composite Application Framework (WS-CAF) [1] to the community. WS-CAF comprises three specifications which together provide a means of reliably composing individual Web Services together into larger aggregate applications. The cornerstone of this suite is the management of stateful interactions between the Web Services which is the domain of the WS-Context specification. WS-CAF was subsequently submitted to OASIS and an effort to standardise the framework is currently underway. In January 2004 a group of industry and academic practitioners from the Grid community released (the first parts of) the Web Services Resource Framework (WS-RF) [2] specifications. WS-RF is intended to support stateful interactions between consumers and resources hosted by Web Services. Clearly there is a degree of overlap between the WS-Context and WS-RF approaches since both support stateful interactions on top of the stateless interaction model championed by Web Services Architecture (WSA). This article examines the different approaches taken by WS-Context and WS-RF, concentrating in particular on how each approach facilitates stateful interactions in composite Web Services-based applications.