The World Wide Web Consortium (W3C) has issued the Web Services Choreography Description Language Version 1.0 as a W3C First Public Working Draft. The Web Services Choreography Description Language (WS-CDL) is targeted to coordinate interactions among Web services and their users. This is the first in the series of WS-CDL drafts. The WS-CDL specification defines peer-to-peer collaboration between Web service participants. A user of a Web service, automated or otherwise, is a "client" of that service. Users may be other Web services, applications and human beings. In WS-CDL, a set of client interactions may be related over time in a "collaboration group." A collaboration group could be, for example, a set of components that make up a business transaction or a database transaction.
The WS-CDL specification brings together resources from both industry and research. WS-CDL incorporates not only business requirements, but also mathematical work in pi calculus, an algebra based on naming used to model systems that are physically or virtually mobile. Invited Experts in the W3C Web Services Choreography Working Group include Professor Robin Milner, the principal creator of pi calculus; Dr. Kohei Honda; and Dr. Nobuko Yoshida. Their collective work on pi calculus and correctness properties (livelock, deadlock and leak freedom) is the underpinning of WS-CDL, giving the language mathematical soundness.
The W3C Web Services Choreography Working Group published Web Services Choreography requirements and its model overview last month. The Working Group designed this foundation for WS-CDL to be consistent with Web Services Architecture, and to augment the Architecture of the World Wide Web, First Edition, a work in progress by the W3C's Technical Architecture Group (TAG). WS-CDL is XML-based and supports SOAP Version 1.2, WSDL 2.0, and the Web's architectural layers. As all W3C Web Services Working Groups are required to coordinate with each other in an effort to ensure a smooth and sound infrastructure, WS-CDL is designed to be interoperable with all deliverables in the W3C Web Services Activity. The Web Services Choreography Working Group is now focusing its attention on refining WS-CDL, with the intention of developing early implementations. W3C invites the Web development community to review and comment on this publication and subsequent drafts.
The participants in the W3C Web Services Choreography Working Group (in alphabetical order) are Apple Computer; Arjuna Technologies Ltd; BEA Systems; Choreology Ltd; Cisco Systems; Commerce One; Computer Associates; DSTC Pty Ltd (CITEC); EDS; Enigmatec Corporation; Fujitsu Ltd; Hewlett-Packard; Hitachi, Ltd.; Intalio Inc.; IONA; MTA SZTAKI; National Computerization Agency; Nortel Networks; Novell; Oracle; SAP AG; SeeBeyond Technology Corporation; Software AG; Sonic Software; Sun Microsystems, Inc.; Thomson Corporation; TIBCO Software; Uniform Code Council; University of Maryland (Mind Lab); W. W. Grainger, Inc.; webMethods, Inc., and Invited Experts Dr. Honda, Professor Milner, and Dr. Yoshida. The group is chaired by Martin Chapman (Oracle) and Steve Ross-Talbot (Enigmatec).