Requirements for workflow modeling in P2P - workflows derived from collaboration establishment

Web services advocate loosely coupled systems, although current applications are limited to centrally controlled structures. The reason for this limitation is the lack of a method for deciding collaboration consistency, that is deadlock freeness and boundedness, in a decentralized way. In particular, an intuitive approach classifies collaborations incorrectly being inconsistent due to the loss of information introduced by the decentralization. In this paper we identify loss of message ordering and message parameter value constraints caused by the decentralization to be the reasons for incorrect decision results. The proposed approach to overcome this issue is to explicate these constraints, which cannot represent in common workflow models.