The Internet is a loose association of thousands of networks and millions of
computers across the world that all work together to share information.
Like many complex systems, the Internet is easiest to explain through the use of
metaphors, and the Net has inspired its fair share. The one that has stuck is the
"information superhighway," and while it has become a clich�, the transportation
analogy really does hold up pretty well. Think of the Internet as a mondo version of a mass transit system like Boston's T, with a few main subway lines that intersect at certain points. Connecting to the subway lines are commuter rails, bus lines, and
ferry boats that spread out and crisscross the metropolitan area.
On the Net, the main lines carry the bulk of the traffic and are collectively known as the Internet backbone. The backbone is formed by the biggest networks in the
system, owned by major Internet service providers (ISPs) such as GTE, MCI,
Sprint, UUNet, and America Online's ANS.
By connecting to each other, these networks create a superfast pipeline that
crisscrosses the United States and extends to Europe, Japan, mainland Asia, and the rest of the world. But that doesn't mean that the network is equally well developed at every point along the route. The U.S. backbone has so many intersecting points that if one part fails or slows down, data can be quickly rerouted over another part, a feature called redundancy. Overseas, the network may have less redundancy and so
be more vulnerable to slowdowns or breakdowns.
In the United States, there are five points--located in San Francisco, San Jose
(California), Chicago, New York (actually, Pennsauken, New Jersey), and
Washington, D.C.--where the main lines intersect, kind of like how the major U.S.
airlines have hub cities. Confusingly enough, three of these are called network
access points (NAPs), while the other two are called metropolitan area exchanges
(MAEs), but they basically do the same thing: use high-speed networking equipment
to connect the backbone to other networks These networks are owned by smaller regional and local ISPs, which in turn lease access to companies and individuals in the areas they serve.
Government agencies and universities are also actively involved in running the parts of the Internet that link supercomputer centers devoted to the research and education communities. While this used to be the main purpose of the Net, the explosion of private and corporate use has caused a huge traffic jam on the backbone. Academics now complain that they can't get their work done because the network is too packed with everybody else.
With help from these communities, as well as financial support from the private
sector, Congress has been actively planning the Next Generation Internet. It aims to
deliver on President Clinton's pledge to build and promote a new and faster network
that will form a second backbone over the next five years. This Internet II, as it's
sometimes called, will not replace the existing Net, but will provide alternate routes for academics and government agencies to share information without getting caught in commercial traffic.
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