Overlays vary in bandwidth, latency, coverage, and application-level performance visibility (see table). We are developing innovative overlay internetwork management and applications support services allowing mobile applications to operate across a wide range of network performance, roaming among potentially distrusting service providers, and choosing among alternative overlays for best performance given the current network state and application requirements. The architecture, algorithms, and protocols are designed to scale to more users, clustered in higher densities, with increasing demands for integration with wireline storage and computational resources.
Our overlay internetwork architecture, supporting mobility-enabled media-intensive applications-like those needed for (near) real-time observation of the battlefield and coordination of forces-will exploits logical hierarchies, geographical locality, and distributed processing to decentralize network control decisions within and across the overlays. Users and their network demands are tracked, to assist in efficient resource allocation.
We are demonstrating our technology in a wireless overlay network testbed being created in the San Francisco Bay Area as a collaboration with Digital Equipment Corporation, GM Hughes Electronics, IBM, Metricom, Nextel, and Pacific Telesis. They provide us with network access, spanning from in-building to satellite systems. We are developing pilot applications to drive the design and validation of the interfaces between applications and the network. Our overarching goal is to demonstrate a scalable architecture that can support wireless access across multiple overlay networks while delivering high levels of end-to-end performance to applications.