Data communication networks — An introduction: Innovative developments are revolutionizing worldwide communications

Thousands of data communication networks are deployed worldwide to enhance the ability of data users to communicate with one another. They range from small networks interconnecting data terminals and computers within a single building or campus-like complex, to large geographically-distributed networks covering entire countries or, in some cases, spanning the globe. Some networks are privately-operated; others are public, available for a fee. Some use packet-switching technology, with blocks of data called packets transmitted from a source to a destination. Source and destination can be terminals, computers, printers, or any other types of data communicating and/or handling devices. In this technology multiple users share the same distribution and transmission facilities.