and that growth is responsive to new technologies and emerging needs. For this reason, while computing and communications technologies have taken hold in numerous specific application areas within these sectors, in most cases the challenge remains for advanced information technology to take on a significant sectorwide infrastructural role.
The NII, in the simplest terms, consists of available, usable, and interoperable computing and communications systems, built on underlying communications channels (the bitways) and providing a broad range of advanced information technology capabilities (the services). These services provide the basis for a wide range of use (the applications), ranging in scale up to national challenge applications. A key point is that NII is far more than communications connectivity; indeed it is generally independent of how communications connectivity is supplied.
Generally speaking, infrastructural systems consist of ubiquitous shared resources that industry, government, and individuals can depend on to enable more productive and efficient activity, with broadly distributed benefit (Box 1). The resources can include physical assets, such as the national air-traffic control system or the nationwide highway system. The resources can also include key national standards, such as the electric power standards, trucking safety standards, railroad track structure, and water purity standards. The resources are ubiquitous and reliable to an extent that all participants can commit to long-term investment dependent on these resources. This also implies a capacity for growth in scale and capability, to enable exploitation of new technologies and to assure continued value and dependability for users. The value can be in the form of increased quality and efficiency, as well as new opportunities for services.
It is therefore clear that a critical element of NII development is the fostering of appropriate commonalities, with the goal of achieving broad adoptability while promoting efficient competition and technological evolution. Commonalities include standard or conventional interfaces, protocols, reference architectures, and common building blocks from which applications can be constructed to deliver information services to end users. A fundamental issue is management and evolution, and in this regard other examples of national infrastructure reveal a wide range of approaches, ranging from full government ownership and control to private-sector management, with government participation limited to assurance of standard setting.
The Clinton Administration, under the leadership of Vice President Gore, has made national information infrastructure a priority (Gore, 1991; Clinton and Gore, 1993), as have other nations (examples: NCBS, 1992, and Motiwalla et al., 1993). The NII vision embraces computing and communications, obviously areas of considerable private investment and rapid technological change. The definition of the government role in this context has been ongoing, but several elements are clear. At the national policy level, the NII agenda embraces information and telecommunications policy, issues of privacy and rights of access, stimulation of new technologies and standards, and early involvement as a user (IITF, 1993). The federal High Performance Computing and Communications (HPCC) program, and the advanced information technologies being developed within it, play a key role in addressing the research and technical challenges of the NII.
In this paper we examine several aspects of the conceptual and technological challenge of creating information infrastructure technologies and bringing them to fruition in the form of an NII built by industry and ubiquitously adopted in the NC applications sectors. Topics related to telecommunications policy, intellectual property policy, and other aspects of information policy are beyond our scope.
In the first section below, we examine the federal government's role in fostering NII technologies and architecture. We then analyze the relationship between high-performance technologies and the NII and describe our three-layer NII vision of applications, services, and bitways. This vision is expanded in the next two sections, in which the NC applications and the technologies and architectural elements of the services layer are discussed. We present the research agenda of the Federal High Performance Computing and Communications Program in the area of information infrastructure technologies and applications, followed by our conclusions.