Extensible optimization in overlay dissemination trees

We introduce XPORT, a profile-driven distributed data dissemination system that supports an extensible set of data types, profile types, and optimization metrics. XPORT efficiently implements a generic tree-based overlay network, which can be customized per application using a small number of methods that encapsulate application-specific data filtering, profile aggregation, and optimization logic. The clean separation between the "plumbing" and "application" enables the system to uniformly support disparate dissemination-based applications.We first provide an overview of the basic XPORT model and architecture. We then describe in detail an extensible optimization framework, based on a two-level aggregation model, that facilitates easy specification of a wide range of commonly used performance goals. We discuss distributed tree transformation protocols that allow XPORT to iteratively optimize its operation to achieve these goals under changing network and application conditions. Finally, we demonstrate the flexibility and the effectiveness of XPORT using real-world data and experimental results obtained from both prototype-based LAN emulation and deployment on PlanetLab.