Page 914 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

WAN Technologies

Wide area network links are used to connect distant networks, nodes,
or individual devices together. This can improve communications and
efficiency, but it can also place data at risk. Proper connection

management and transmission encryption is needed to ensure a
secure connection, especially over public network links. WAN links
and long-distance connection technologies can be divided into two
primary categories:

A dedicated line (also called a leased line or point-to-point link) is one
that is indefinably and continually reserved for use by a specific
customer (see Table 12.3). A dedicated line is always on and waiting

for traffic to be transmitted over it. The link between the customer’s
LAN and the dedicated WAN link is always open and established. A
dedicated line connects two specific endpoints and only those two
endpoints.

TABLE 12.3 Examples of dedicated lines

Technology Connection Speed
Type

Digital Signal Level 0 (DS-0) Partial T1 64 Kbps up to 1.544
Mbps

Digital Signal Level 1 (DS-1) T1 1.544 Mbps

Digital Signal Level 3 (DS-3) T3 44.736 Mbps

European digital transmission El 2.108 Mbps
format 1

European digital transmission E3 34.368 Mbps
format 3

Cable modem or cable routers 10+ Mbps

A nondedicated line is one that requires a connection to be established

before data transmission can occur. A nondedicated line can be used
to connect with any remote system that uses the same type of
nondedicated line.