Overview

The Internet of today has its roots in the US-Soviet Cold War of the 1960s as a means of communications that would survive a nuclear war. Today, it is one of the primary means of communicating information worldwide in digital form.

The Internet of today began as a single network sponsored as a research project by the US Department of Defense: the ARPANET. Its early architecture and protocols were relatively simple; it was a single network providing connectivity for a modest (by today's standards) number of computer systems. Expansion of this network, together with the need to interconnect with other existing networks, led to a change in architecture. The ARPANET first divided in two (the MILNET/ARPANET division of 1983), and regional networks began to provide connectivity and entry into the ARPANET for locations not directly connected. The ARPANET had become the first de facto backbone network for a group of interconnected netoworks -- the Internet.

This architecture -- a national backbone with regional "spur" networks -- was formally adopted by the National Science Foundation with its NSFNET project. In NSFNET, a high speed national backbone network (initially T1, later T3) was developed that connected major national supercomputer sites; regional and other networks were connected to this network, while subscriber nodes connected to these other networks.

The NSFNET was quite successful while it operated. However, the NSFNET architecture was ended in April, 1995, in favor of a commercially provided multiple backbone architecture. In this new architecture, multiple commercial National Service Providers (NSPs) provide high-speed nationwide backbone connectivity; these different backbone networks are interconnected at National Access Points (NAPs). Internet users are provided access through Internet Service Providers (ISPs); these connect to the multiple national backbones at one or more of the NAPs.

The US federal government has announced the creation of a "National Information Infrastructure" to be based on today's Internet. While the exact architecture of this concept is not terribly well defined, certain future trends are clear. These future trends for the Internet are apparent in two areas: increasing speed and interconnection of the NSPs. The federal government, under its National Research and Education Network (NREN) program, is in the process of implementing a very high-speed backbone network (vBNS) to interconnect supercomputer facilities; when implemented, this will provide an alternate and extremely high speed national backbone. Many larger cities are served by multiple NAPs, while ISPs frequently have arrangements with more than one NAP. A large city that does not have an NAP nevertheless may have a high degree of interconnection between NAPs and may operate as a lower-capacity "pseudo NAP."

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