A Formal Model for Web Service Choreography Description Language (WS-CDL)

The Web Services Choreography Description Language (WS-CDL) is a specification of W3C developed for the description of peer-to-peer collaborations of participants from a global viewpoint. For the rigorous definition and tools support for the language, the formal semantics of WS-CDL is worth investigating. This paper proposes a small language CDL as a formal model of simplified WSCDL, which includes many important concepts related to participant roles and collaborations among them in a choreography. The formal operational semantics of CDL is given, and static validation and verification of choreographies is studied as well. A purchase order choreography example is presented, and some properties of the proposed model are verified using the SPIN model-checker, which illustrates the potential usages and benefits of the formal model.