Federating Process-Centered Environments: The Oz Experience

We describe two models for federating process-centered environments (PCEs): homogeneous federation among distinct instances of the same environment framework enacting the same or different process models, and heterogeneous federation among diverse process enactment systems. We identify the requirements and consider possible architectures for each model, although we concentrate primarily on the homogeneous case. The bulk of the paper presents our choice of architecture, and corresponding infrastructure, for homogeneous federation among MARVEL environment instances as realized in the OZ system. We briefly consider how a single MARVEL environment, or an OZ federation of MARVEL environments, might be integrated into a heterogeneous federation based on ProcessWall's facilities for interoperating PCEs.