Page 826 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

against far-end crosstalk. In 2001, the TIA/EIA-568-B no longer
recognized the original Cat 5 specification. Now, the Cat 5e

standard is rated for use by 100BaseT and even 1000BaseT
deployments.

The following problems are the most common with twisted-pair
cabling:

Using the wrong category of twisted-pair cable for high-throughput
networking

Deploying a twisted-pair cable longer than its maximum
recommended length (in other words, 100 meters)

Using UTP in environments with significant interference

Conductors

The distance limitations of conductor-based network cabling stem
from the resistance of the metal used as a conductor. Copper, the most
popular conductor, is one of the best and least expensive room-
temperature conductors available. However, it is still resistant to the
flow of electrons. This resistance results in a degradation of signal
strength and quality over the length of the cable.

Plenum cable is a type of cabling sheathed with a special

material that does not release toxic fumes when burned, as does
traditional PVC coated wiring. Often plenum-grade cable must be

used to comply with building codes, especially if the building has
enclosed spaces that could trap gases.

The maximum length defined for each cable type indicates the point at
which the level of degradation could begin to interfere with the
efficient transmission of data. This degradation of the signal is known
as attenuation. It is often possible to use a cable segment that is longer
than the cable is rated for, but the number of errors and
retransmissions will be increased over that cable segment, ultimately

resulting in poor network performance. Attenuation is more