NRI will conduct a research program on very high speed networks in cooperation with industry, academia, national laboratories, and several major supercomputer centers to explore alternative very high-speed architectures and to determine how to utilize them most effectively. Three wide-area testbeds and two metropolitan testbeds will be established to carry out experimental portions of the program. Applications of very-high speed networks shall be used as vehicles to explore network performance. These applications include distributed computation, composite visualization, and interactive control of a distributed computation and will be conducted on two of the wide-area testbeds. The technical foci of these testbeds are supercomputer-network interfaces and network integration, respectively. The primary focus of the third wide-area testbed is on switching and network control. One of the metropolitan testbeds focuses on interfacing workstations and supercomputers to a gigabit network and developing software to make them work together. The other demonstrates sequential use of distributed resources for interactive display and modification of computer generated images.