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of capabilities would have cost implications and is economically feasible only to the extent that it provides value to the user well in excess of the incremental costs. This is problematic if one accepts one of our fundamental hypotheses, namely, that we cannot possibly anticipate all the big-hitting applications of the NII. However, it should be emphasized that it is not necessary that all near-term deployments provide all the capabilities incorporated into a strategic vision. Indeed, one critical aspect of such a vision is that it should be easy and cost effective to add new technologies and capabilities to the NII as unanticipated applications and user needs emerge. If this is achieved, it is only necessary that near-term investments be compatible with a long-term strategic vision, and hence not preclude future possibilities or force later disinvestment and widespread replacement of infrastructure. This is admittedly not straightforward but is nevertheless a worthwhile goal.

One can anticipate the NII falling somewhere on the spectrum from a collection of proprietary and noninteroperable networks (largely the situation today) to a single, universal network that appears to the user to seamlessly and effortlessly meet all user needs. We argue that from the user perspective the NII should, although consisting internally of a diversity of heterogeneous transport and terminal technologies, offer the seamless deployment of a wide range of applications and openness to new applications. Not all participants in the NII may judge this to be in their best interest, and of course they all encounter serious cost and time-to-market constraints. However, if they take into account longer-term opportunities in the course of their near-term business decisions, we believe that both they—the users—and the nation will benefit greatly in the long term. It is our hope that the NII 2000 technology deployment project will move the collective deliberations in this direction.

Terminology

First we define some consistent terminology for the remainder of this white paper.

The users of the NII are people. The NII will consist of a network (or more accurately a collection of networks) to which are attached access nodes at its edge. We distinguish between two types of devices connected to access nodes: information and applications servers, and user terminals (for simplicity, we will abbreviate these to servers and terminals). A networked application is a set of functionality that makes use of the transport services of the network and the processing power in the servers and terminals, and provides value to users. Servers make databases or information sources available to the terminals, or provide processing power required to provision applications. Users interact directly with terminals, which provide the user interface and may also provision processing power or intelligence in support of applications. Examples of terminals are desktop computers, wireless handheld PDAs, and CATV set-top boxes.

There are two generic classes of applications: user-to-user or communications applications, and user-to-server or information access applications. These can be mixed, for example, a collaborative application that combines voice telephony with database access.

The business entities involved in the operation of the NII are network service providers, who provision the transmission and switching equipment in the network, and application service providers, who provision the servers and maintain the databases involved in the applications. These may be one and the same, as is the case for the telephone application in the public telephone network. The users may be the application service provider, as when they load software purchased at a computer store on their terminals. Other entities involved are the equipment vendors, who develop, manufacture, and market the equipment (transmission, switching, terminals, etc.), and the application vendors, who develop and market applications for deployment in the NII.

Connectivity Issues

Logical Connectivity of a Network

The most basic property of a network from a user perspective is the logical connectivity it offers. The network is said to provide logical connectivity between two access nodes if it is feasible to transport data between those nodes through the network. When one access node sends data to another access node, we call the former the