Forschungsberichte des Fachbereichs Informatik Bericht Nr . 999 Federated Information Systems : Concepts , Terminology and Architectures

We are currently witnessing the emerging of a new generation of software systems: Federated information systems. Their main characteristic is that they are constructed as an integrating layer over existing legacy applications and databases. They can be broadly classified in three dimensions: the degree of autonomy they allow in integrated components, the degree of heterogeneity between components they can cope with, and whether or not they support distribution. Whereas the communication and interoperation problem has come into a stage of applicable solutions over the past decade, semantic data integration has not become similarly clear. This report clarifies definitions and terms in the research area of integration of heterogeneous and distributed information systems. It gives classification criteria for such systems and particularly defines mediator-based information systems as we understand them. The definition of terms is accompanied by the identification of relevant concepts and reference architectures. We also closely relate our work to a number of other prominent classifications.