Page 833 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

for networking, connectivity, communication, and data exchange.

There are literally thousands of protocols, standards, and techniques
that can be labeled as wireless. These include cell phones, Bluetooth,
cordless phones, and wireless networking. As wireless technologies
continue to proliferate, your organization’s security efforts must go
beyond locking down its local network. Security should be an end-to-
end solution that addresses all forms, methods, and techniques of
communication.

General Wireless Concepts

Wireless communications employ radio waves to transmit signals over
a distance. There is a finite amount of radio wave spectrum; thus, its
use must be managed properly to allow multiple simultaneous uses
with little to no interference. The radio spectrum is measured or
differentiated using frequency. Frequency is a measurement of the
number of wave oscillations within a specific time and identified using
the unit Hertz (Hz), or oscillations per second. Radio waves have a

frequency between 3 Hz and 300 GHz. Different ranges of frequencies
have been designated for specific uses, such as AM and FM radio, VHF
and UHF television, and so on. Currently, the 900 MHz, 2.4 GHz, and
5 GHz frequencies are the most commonly used in wireless products
because of their unlicensed categorization. However, to manage the
simultaneous use of the limited radio frequencies, several spectrum-

use techniques were developed. These included spread spectrum,
FHSS, DSSS, and OFDM.

Most devices operate within a small subsection of

frequencies rather than all available frequencies. This is because of
frequency-use regulations (in other words, the FCC in the United
States), power consumption, and the expectation of interference.

Spread spectrum means that communication occurs over multiple
frequencies at the same time. Thus, a message is broken into pieces,
and each piece is sent at the same time but using a different frequency.
Effectively this is a parallel communication rather than a serial