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In its most basic form, a computer network involves a linkage between two computing devices, i.e., two computers or a computer and a printer. The number of terms used to describe various types of networks has proliferated dramatically in the past 30 years, but the fundamental principles remain unchanged. Networking implies that two computing devices have packaged the information they wish to exchange in a format both agree upon and they communicate across a shared exchange medium (such as an Ethernet connection) (Fig. 3-1).
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One of the earliest “networks” was developed at Xerox’s experimental laboratory in Palo Alto, California, known as the Palo Alto Research Center, or PARC. PARC’s mission was the development of the “office of the future.” Founded in 1970, the lab developed and patented innovative computer components including Ethernet networking, the graphical user interface later popularized by Apple, the laser printer, and spell checking. Ethernet is one of the prototypical computer networking standards, and it was developed at PARC by Bob Metcalfe. Metcalfe developed the cabling method and communication standards governing communication between an early personal computer, the Alto, and a printer. This subsequently evolved into the Ethernet standard, which has become the most popular and widely deployed networking standard in the world.
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The original Ethernet standard described communications among devices on a single cable attached to all of the devices on the network (Fig. 3-2), and permitted conversations between any single device and all of the other devices (i.e., computer, printer, and so on) on that cable (Fig. 3-3).
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Today’s networks theoretically permit ad hoc conversations between any two users connected to the Internet at any time. Networks are now defined by security standards and firewalls rather than physical boundaries to a network. This is a miraculous concept in many regards, but as with the physiologic body, any computer can act like a cell and become the portal of entry for a virus and infect a network system.
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Key Points
Network Terminology
Ethernet is the progenitor network protocol.
Local area networks (LANs) and wide area networks (WANs) are common terms used to describe the geographic extent of a network.
There are various ways of wiring computers together such as “twisted pair,” coaxial cable, and optical ...