Tuesday, December 3, 2019
The History Of The Internet Essays - Network Architecture
The History of the Internet The History of the Internet The Internet has update the computer and communications world like nothing before. The invention of the telegraph, telephone, radio, and computer set the stage for this unprecedented integration of capabilities. The Internet is at once a world-wide broadcasting capability, a mechanism for information distribution, and a medium for collaboration and interaction between individuals and their computers without regard for geographic location. The Internet represents one of the most successful examples of the benefits of sustained investment and commitment to research and development of information infrastructure. Beginning with the early research in packet switching, the government, industry and academia have been partners in evolving and deploying this exciting new technology. Over its fifteen year history, the Internet has functioned as a collaboration among cooperating parties. Certain key functions have been critical for its operation, not the least of which is the specification of the protocols by which the components of the system operate. To get to the origins of the Internet, we have to go back in time to 1957. You probably have no cause to remember, but it was International Geophysical Year, a year dedicated to gathering information about the upper atmosphere during a period of intense solar activity. Eisenhower announced in 1955 that, as part of the activities, the USA hoped to launch a small Earth orbiting satellite. Then Kremlin announced that it hoped to do likewise. Planning in America was focussed on a sophisticated three stage rocket, but in Russia they took a more direct approach, on 4 October 1957 the USSR launched (a 70 kgs bleeping sphere the size of a medicine ball) into Earth orbit. The effect in the United States was electrifying, since it seemed overnight to wipe out the feeling on invulnerability the country had enjoyed since the explosion of the first nuclear bomb thirteen years before. One of the immediate reactions was the creation of the Advanced Research Projects Agency within the Ministry of Defense. Its mission was to apply state-of-the-art technology to US defense and to avoid being surprised (again!) by technological advances of the enemy. It was also given interim control of the US satellite program until the creation of NASA in October 1958. ARPA became the technological think-tank of the American defense effort, employing directly a couple of hundred top scientists and with a budget sufficient for sub-contracting research to other top American institutions. Although the advanced computing would come to dominate its work, the initial focus of ARPA's activities were on space, ballistic missiles and nuclear test monitoring. Even so, from the start ARPA was interested in communicating between its operational base and its sub-contractors, preferably through direct links between its various computers. In October 1972 ARPANET went 'public'. At the First International Conference on Computers and Communication, held in Washington DC, ARPA scientists demonstrated the system in operation, linking computers together from 40 different locations. This stimulated further research in scientific community throughout the Western World. Soon other networks would appear. Here we have the first true computer network. Since it is all still fairly basic, it is worth considering the underlying principles have basically remained the same (even if they, mercifully, operate far faster and look much prettier). We start off with a passive terminal and an active host, a keyboard and a computer. They are linked together by a cable. By typing in commands recognized by a computer, you can use the programs stored in its computer, access its files (and modify them and print them out as desired). Most people can envisage this arrangement within a single building, or complex of buildings. The original ARPANET grew into the Internet. The Internet was based on the idea that there would be multiple independent networks of rather arbitrary design, beginning with the ARPANET as the pioneering packet switching network, but soon to include packet satellite networks, ground-based packet radio networks and other networks. The Internet as we now know it embodies a key underlying technical idea, namely that of open architecture networking. In this approach, the choice of any individual network technology was not dictated by a particular network architecture but rather could be selected freely by a provider and made to interwork with the other networks through a meta-level "Internetworking Architecture". Up until that time there was only one general method for federating networks. This was the traditional circuit switching method where networks would interconnect at the circuit level, passing individual bits on a synchronous basis along a portion of an end-to-end circuit between a pair of end locations. Recall that Kleinrock had shown in 1961 that packet switching was a more
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