Page 181 - CISSO_Prep_ Guide

such as a switch. The switch can send traffic that is going from a
device on one port to a device connected to another port directly
and not send the data to every other port. This means that the
traffic on a switch is a bit harder to monitor unless you have
direct access to the switch. This can also have the advantage that
a lot of traffic between two parties will not have, and as much
impact on the other devices as would happen on a bus type
network.

The advantages of a star network include the flexibility and ease
of administration when all devices can be accessed from a single
location. These networks tend to operate quite quickly, and it is
easy to connect and disconnect devices or change their
configuration. However, the disadvantages are cost and the fact
that the switch and server room may be single points of failure if
something happens to the switch, or there is a problem in the
wiring closet or server room, everything can be compromised.

Virtual Local Area Networks (VLANs)

A switched network may also be divided into a set of smaller
networks through the use of a VLAN. A VLAN separates the
traffic from some ports on a switch from the traffic for other
ports on the same switch. In this way, the switch is logically
managing the traffic to the various devices on its ports as if they
were on several different physical networks.

A VLAN may also provide logical management of traffic on
several different switches so that devices connected to one
switch may be treated as if they were on the same physical
network being managed by another switch.