Open systems architectures: from monolithic approaches to service-based architectures

Systems interoperability and business process synchronization have always been major issues in Enterprise Integration, be it integration of a single enterprise or of a network of enterprises. Until recently, the state of the art was to develop integrated enterprise architectures on the basis of integration infrastructures (e.g., OSF/DCE, OMG/CORBA) or proprietary Enterprise Application Integration (EAI) solutions, possibly integrating workflow systems. These kinds of architectures turn out to be complex, monolithic and too rigid. The new generation of open systems architectures takes advantage of distribution of functionality, which can be provided by dedicated servers shared by various users over web-based infrastructures (Web Services), open standards such as XML/SOAP for enterprise-wide communication, and highly portable infrastructures such as J2EE or .NET platforms. The paper first reviews the evolution in the field of Enterprise Integration and Interoperability. It then presents essential principles to apply to build scalable service-based architectures. Finally, a corporate integrated information system architecture is proposed that takes advantage of a clear separation between the Application System (where the business processes are executed), the Storage System (where data and documents are stored) and the Meta-Data System (mediating between the two).