Page 821 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

Cabling, Wireless, Topology,

Communications, and Transmission Media

Technology

Establishing security on a network involves more than just managing
the operating system and software. You must also address physical
issues, including cabling, wireless, topology, and communications

technology.

LANs vs. WANs

There are two basic types of networks: LANs and WANs. A local
area network (LAN) is a network typically spanning a single floor
or building. This is commonly a limited geographical area. Wide

area network (WAN) is the term usually assigned to the long-
distance connections between geographically remote networks.

WAN connections and communication links can include private
circuit technologies and packet-switching technologies. Common
private circuit technologies include dedicated or leased lines and
PPP, SLIP, ISDN, and DSL connections. Packet-switching
technologies include X.25, Frame Relay, asynchronous transfer

mode (ATM), Synchronous Data Link Control (SDLC), and High-
Level Data Link Control (HDLC). Packet-switching technologies
use virtual circuits instead of dedicated physical circuits. A virtual
circuit is created only when needed, which makes for efficient use
of the transmission medium and is extremely cost-effective.

Transmission Media

The type of connectivity media employed in a network is important to

the network’s design, layout, and capabilities. Without the right
cabling or transmission media, a network may not be able to span
your entire enterprise, or it may not support the necessary traffic
volume. In fact, the most common causes of network failure (in other