Lecture2 - Computer Networks ECE-CSE 861: Introduction to...

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1 ECE-CSE 861: Introduction to Computer Communication Networks Ness B. Shroff ECE & CSE Lecture 2 Computer Networks First computer network was the semi-automatic ground environment (SAGE) system developed between 1950 to 1956 for air defense systems [Green 1984]. SAGE consisted of 23 computer networks, each network connecting radar sites, ground-to-air data links, and other locations to a central computer. Early computers were extremely expensive, so techniques were developed to allow them to be shared by many users. Time-sharing led to the development of terminal-oriented networks. Architecture: tree topology with with the host computer as the root node. ARPANET As the cost of computers dropped, it became important to connect more than one computer. The ARPANET was the first major effort at developing a network to interconnect computers over a wide geographic area. Funding was provided by the Advanced Research Projects Agency (ARPA) of the U.S. Department of Defense (now DARPA). Users of this network were actual computers, not terminals, hence it became possible to develop sophisticated networking protocols. These protocols were developed at the edge of the network (at the computers) to simplify the operation within the network ( in significant contrast to the telephone network, where the intelligence resides within the network and not the telephone
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This note was uploaded on 03/18/2012 for the course ECE 861 taught by Professor Shroff during the Spring '11 term at Ohio State.

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Lecture2 - Computer Networks ECE-CSE 861: Introduction to...

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