The predictable and high rate of progress in hardware has fueled rising expectations for distributed information networks of immense capacity, capability, flexibility, and reach. These expectations, however, are constrained by technical, regulatory, and economic challenges on national and international levels. The principal obstacles lie in the areas of telecommunications and software technology, commonly referred to as the "bottlenecks" that impede progress toward large-scale information networks offering widely available services. Simply stated, the technical problems are these: First, the information processing capabilities of computers greatly exceed the capabilities of public telecommunication carriers to transmit data in its many forms between remote computers; data arrive in trickles rather than in the torrents that are needed to support real-time, multimedia interactive computing. Second, advances in hardware have outraced the ability of software designers and computer programmers to develop applications that exploit the full capabilities of new devices. The gap between potential performance and the actual functionality supplied by software applications remains large, and, at the same time, software accounts for a large and growing expense in the development of information technology. Third is a combined telecommunications and software problem. Software of high reliability and quality is a critical component of efforts to improve the transmission capacity and capabilities of telecommunications carriers, as evidenced by the fact that software may account for as much as 80 percent of the cost of a telecommunications system.1,2 Building an infrastructure and implementing the associated services necessary to achieve the seamless connection of information networks on national and global scales pose large, complex challenges for software development. Finally, it is not enough to develop technological solutions to the impediments that prevent high-speed, high-performance networking. There must also be agreement between the telecommunications and computer industries on how those solutions should be implemented into standards. Moreover, to promote global networking, standards development within nations should complement the work of international standards-setting bodies.
Although telecommunications and software issues loom large, technical challenges also face manufacturers of integrated circuits and the other hardware components of information technology. For example, in addition to new software, faster and more powerful microprocessors, perhaps using photonic technology, will be needed to achieve the high switching speeds necessary for rapid transmission between computers of large volumes of data in multimedia forms. Moreover, as communications performance improves, computers and other digital equipment, whose capabilities are now constrained by slow data transmission, will eventually be hard pressed to assimilate data arriving at rates exceeding a billion bits per second, as envisioned for the National Research and Education Network (NREN), a