Network Tutorial, Fifth Edition
This text is written for those trying to get up to speed or stay current with the complex challenges of designing, constructing, maintaining, upgrading, and managing the network infrastructure.
TABLE OF CONTENTS Network Tutorial, Fifth Edition
Section VI: Network Hardware
Cabling
Cable is the medium that ordinarily connects network devices. Cable's ability to transmit encoded signals enables it to carry data from one place to another. These signals may be electrical as in copper cable or light pulses as in fiber-optic cable.
A few networks don't use cable at all. Instead, data is carried through the air as microwave, infrared, radio frequency, or laser-produced visible light signals. These wireless networks are often expensive, and may require licenses from the Federal Communications Commission. When the cost of running cable is prohibitively high or a network must be mobile or temporary, a wireless LAN can make sense.
Three Choices
Network users have three basic cable choices: coaxial, twisted-pair, and fiber-optic. Coaxial and twisted-pair cables both use copper wire to conduct the signals; fiber-optic cable uses a glass or plastic conductor. Before the Ethernet standards for unshielded twisted-pair installations were approved in 1992, the majority of LANs used coaxial cable, but a high proportion of subsequent installations have used the more flexible and less costly unshielded twisted-pair medium. The use of fiber-optics in local networks is growing, albeit slowly. Fiber is most often used on the backbone network and is not commonly run to the desktop.
Originally, access protocols were tied to cable type. Ethernet and ARCnet ran on coaxial cable only. (Most of the installed coaxial cable is there because Ethernet and ARCnet have been around for so long.) However, these protocols have since been modified to run on shielded and unshielded...
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