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The Internet, sometimes called the Net, is a worldwide system of computer networks -- a network of networks in which users
at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to
users at other computers).
The Internet is a cooperative and self-sustaining facility accessible to hundreds of millions of people worldwide. Physically,
the Internet uses a portion of the total resources of the currently existing public telecommunication networks. Technically,
what distinguishes the Internet is its use of a set of protocols called TCP/IP (Transmission Control Protocol/Internet Protocol).
Two recent adaptations of Internet technology, the intranet and the extranet, also make use of TCP/IP.
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The Internet works because of a network protocol called TCP/IP (Transmission Control Protocol/Internet Protocol). This is
a system that allows computers to describe data electronically to each other over the network.
TCP/IP actually refers to two separate protocols: the transmission control protocol and the Internet protocol. Every computer
that connects to the Internet understands these two protocols and uses them to send and receive data. TCP/IP creates what
is called a packet-switched network. Packet-switched networks were designed to minimize the chance of losing data that is
sent over the wires.
First, TCP breaks down every piece of data, such as an e-mail message, into small chunks called packets. Each packet is
then wrapped in an electronic envelope with an address for both the sender and the recipient. The IP protocol then determines
how the data gets from sender to receiver by passing through a series of routers -- a lot like regular mail goes through
several post offices on its way to its destination.
Each router examines the destination addresses of the packets it receives and then passes them along to another router
on their way to their final destination. Once the packets arrive at their destination, TCP takes over again. It identifies
each packet and verifies that they are intact and then reassembles them into their original form.
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A number of people and events led to the creation of the Internet. We've given a brief summary here. If you're interested
in learning more about the history and creation of the Internet, we recommend the book, Where Wizards Stay Up Late: The
Origins of the Internet by Katie Hafner and Matthew Lyon.
In 1962 a professor at MIT, J.C.R. Licklider wrote about something he called the "Galactic Network" concept -- a global
network through which everyone could share and access data and programs. A few months later, Licklider became the head of
the computer research program at the US Department of Defense's Advanced Research Projects Agency (ARPA), the group that
largely spearheaded and funded the development of the Net.
In 1961 independent research teams in the US and Great Britain began to develop packet-switching and the beginnings of
what would become TCP/IP, the Internet's basic protocol. In 1967 ARPA's Lawrence Roberts published a "Plan for the ARPANet"
computer network which built on these technologies to propose an architectural design for a worldwide network. By 1968 Roberts
had spearheaded the development of the network by issuing a call for bids on creating the first switching hardware and software.
The first switches were developed and designed by a team of engineers over a period of about a year.The first tests were
made at UCLA and then at Stanford in late 1969.
Over the next several years the Internet grew steadily as government agencies, universities, and corporations continued
to come online and to develop protocols and architectures. The Internet made its first public appearance in 1972 at the
Internet Computer Communication Conference. In 1973 and 1974, the TCP/IP protocol emerged in what is essentially its current
form, although its developers continued to refine it throughout the early 1980s.
With protocols and architecture in place, various developers formulated much of the software and services that make up
the Internet. The basic services for connecting to computers remotely (telnet), transferring files over the Net (FTP), and
sending and receiving e-mail appeared in the late 1970s. Usenet news first appeared in 1979. The World Wide Web began in
1989. Since the advent of the Web, the growth of the Internet has skyrocketed. In June 1993, the Web boasted just 130 sites.
A year later, that number had risen to nearly 3,000. As of April 1998, there were more than 2.2 million sites on the Web.
In 1990, the US Government officially decommissioned the ARPANet. Management of the Internet was taken over by the National
Science Foundation (NSF) which renamed the backbone NSFNet. In 1995 management of the Internet and the backbone was turned
over to a consortium of commercial providers. ARPANet and NSFNet were managed by non-profit governmental entities. Since
the money these entities provided for the maintenance and management of the Internet was essentially public, commercialism
on the Net was prohibited and discouraged. The privatization of the Internet and its backbone is in part responsible for
the explosion of growth and commercial activity.
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