business data communications and networking 11th edition-1 : computer science

The Internet is one of the most important developments in the history of both information systems and communication systems because it is both an information system and a communication system. The Internet was started by the U.S. Department of Defense in 1969 as a network of four computers called ARPANET. Its goal was to link a set of computers operated by several universities doing military research. The original network grew as more computers and more computer networks were linked to it. By 1974, there were 62 computers attached. In 1983, the Internet split into two parts, one dedicated solely to military installations (called Milnet) and one dedicated to university research centers (called the Internet) that had just under 1,000 servers. In 1985, the Canadian government completed its leg of BITNET to link all Canadian universities from coast to coast and provided connections into the American Internet. (BITNET is a competing network to the Internet developed by the City University of New York and Yale University that uses a different approach.) In 1986, the National Science Foundation in the United States created NSFNET to connect leading U.S. universities. By the end of 1987, there were 10,000 servers on the Internet and 1,000 on BITNET. Performance began to slow down due to increased network traffic, so in 1987, the National Science Foundation decided to improve performance by building a new high-speed backbone network for NSFNET. It leased high-speed circuits from several IXCs and in 1988 connected 13 regional Internet networks containing 170 LANs (local area networks) and 56,000 servers. The National Research Council of Canada followed in 1989 and replaced BITNET with a high-speed network called CA*net that used the same communication language as the Internet. By the end of 1989, there were almost 200,000 servers on the combined U.S. and Canadian Internet. Similar initiatives were undertaken by most other countries around the world, so that by the early 1990s, most of the individual country networks were linked together into one worldwide network of networks. Each of these individual country networks was distinct (each had its own name, access rules, and fee structures), but all networks used the same standards as the U.S. Internet network so they could easily exchange messages with one another. Gradually, the distinctions among the networks in each of the countries began to disappear, and the U.S. name, the Internet, began to be used to mean the entire worldwide network of networks connected to the U.S. Internet. By the end of 1992, there were more than 1 million servers on the Internet