The Use of the Internet

A 1970, the United States Defense Department, concerned about the potential breakdown of communications in the case of a nuclear catastrophe, connected existing university computer networks (LANs) with telephone lines (ARPAnet [Advanced Research Project Agency]). This was the beginning of the Internet. It was based on the so-called "packet switching network" concept, which broke an electronic message into packets and re-assembled them at the destination. This way, if parts of the network were not functional, packets could take different routes, being re-assembled at the destination. Messages were sent with Internet Protocol (IP), a special transmission program. Each network, an equal partner in this super-network, could initiate transmissions. In the 1980s, the UNIX computer platform, which had a built-in IP, was introduced, and the National Science Foundation (NSF) created five supercomputer centers (NSFNET). The protocol was changed to Transmission Control Protocol (TCP). (Currently, it is the TCP/IP protocol that is most often used.) By this time, universities could connect to the centers. This was important, because for research purposes, university LAN workstations wanted to communicate with other university LANs. Soon private industry LANs connected, and now private service providers are joining. The World Wide Web (WWW) was developed by CERN (Conseil européen pour la recherche nucléaire the European high energy physics laboratory). The Web permits the display of pages with text, graphics, etc. Although it is difficult to establish an exact breakdown, about half of the network appears to be commer-