Essential Business Process Modeling

WS-CDL

Though WSCI is more famous, the official choreography model blessed by the W3C’s Choreography Working Group is WS-CDL, whose latest working draft was released by the W3C in December 2004.^[*] WS-CDL is a brand-new XML process contract language that provides a standard way to specify technical contracts that capture (from a global viewpoint) the common observable behavior of autonomous interacting participants. The distinguishing characteristics of WS-CDL are the following:

Globally distributed participants, web service interfaces

WS-CDL choreography is seldom confined to applications on a corporate intranet. Rather, the participants are usually from different companies all over the world. Participants use web services to communicate with one anothe, and publish their service interfaces in a WSDL. (WS-CDL supports WSDL Versions 1.1 and 2.0.)

No central controller, just a formal specification

WS-CDL choreography may be global, but WS-CDL does not prescribe a global, centralized control engine to coordinate or manage participant interactions. Instead, each participant has its own engine that executes the participant’s business process. The process, in turn, is required to obey the rules of interaction required by the WS-CDL choreography.

Only publicly observable participant behavior is relevant

A company’s business process can have many steps, but WS-CDL is concerned only with the public face (e.g., in a BPEL process, the receive and invoke activities for relevant partner links).