Page 822 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

words, violations of availability) are cable failures or
misconfigurations. It is important for you to understand that different

types of network devices and technologies are used with different
types of cabling. Each cable type has unique useful lengths,
throughput rates, and connectivity requirements.

Coaxial Cable

Coaxial cable, also called coax, was a popular networking cable type
used throughout the 1970s and 1980s. In the early 1990s, its use
quickly declined because of the popularity and capabilities of twisted-

pair wiring (explained in more detail later). In the 2000s, you are
unlikely to encounter coax being used as a network cable but may still
see some use of it as an audio/visual connection cable (such as with
some cable television equipment or satellite dish equipment, although
the final connection from the service equipment to your television is
most likely HDMI today).

Coaxial cable has a center core of copper wire surrounded by a layer of

insulation, which is in turn surrounded by a conductive braided
shielding and encased in a final insulation sheath.

The center copper core and the braided shielding layer act as two
independent conductors, thus allowing two-way communications over
a coaxial cable. The design of coaxial cable makes it fairly resistant to
electromagnetic interference (EMI) and makes it able to support high
bandwidths (in comparison to other technologies of the time period),

and it offers longer usable lengths than twisted-pair. It ultimately
failed to retain its place as the popular networking cable technology
because of twisted-pair’s much lower cost and ease of installation.
Coaxial cable requires the use of segment terminators, whereas
twisted-pair cabling does not. Coaxial cable is bulkier and has a larger
minimum arc radius than twisted-pair. (The arc radius is the
maximum distance the cable can be bent before damaging the internal

conductors.) Additionally, with the widespread deployment of
switched networks, the issues of cable distance became moot because
of the implementation of hierarchical wiring patterns.

There are two main types of coaxial cable: thinnet and thicknet.