| OverviewRouting in Networks: An Overview
				Electronic networks are developed for creating and distributing
				information.  The two most prominent and successful networks in
				existence are telephone networks and
				the Internet.
				 
				 The telephone network interconnects more than a billion
				telephones worldwide.  In the United States alone, the largest
				telephone company, AT and T, carries nearly 200 million calls
				every day.  Besides voice, the network also carries video,
				facsimile, and telemetry data.
				 
				Every day, the World Wide Web grows by roughly a million electronic
				pages, adding to the hundreds of millions already in use. This
				staggering volume of information is loosely held together by more than
				a billion connections called
				 hyperlinks.
 
				The process of finding a path from a source to every destination in
				the network is called routing. Routing is accomplished by
				means of routing protocols that establish mutually
				consistent routing tables in every router,
				or switch controller.
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