Hardware Reference
In-Depth Information
At a minimum, each network requires the following:
• Physical (cable) or wireless (usually via radio frequency [RF]) connections between
computers.
• A common set of communications rules, known as a
network protocol
.
• Software that enables resources to be served to or shared with other network-enabled
devices and that controls access to the shared resources. This can be in the form of a
network operating system
or
NOS
(suchasolderversionsofNovellNetware)thatruns
ontopofanoperating system; however,currentoperating systems (OSs)suchasWin-
dows, Mac OS X, and Linux also provide network sharing services, thus eliminating
the need for a specialized NOS. A machine sharing resources is usually called a
serv-
er
.
• Resources that can be shared, such as printers, drives, modems, media players, and so
on.
• Software that enables computers to access other computers sharing resources (
serv-
ers
). Systems accessing shared resources are usually called
network clients
. Client
software can be in the form of a program or service that runs on top of an OS. Current
OSs such as Windows, Mac OS X, and Linux include client software.
Theserulesapplybothtothesimplestandthemostpowerfulnetworks,andalltheonesin
between, regardless oftheir nature. The details ofthe hardware andsoftware youneed are
discussed more fully later in this chapter.
Client/Server Versus Peer Networks
AlthougheverydeviceonaLANisconnectedtoeveryotherdevice,theydonotnecessar-
ily communicate with each other. There are two basic types of LANs, based on the com-
munication patterns between the machines: client/server networks and peer-to-peer net-
works.
Client/Server Networks
On a
client/server
network, every computer has a distinct role: that of either a client or a
server. A
server
is designed to share its resources among the client computers on the net-
work.Typically,serversarelocatedinsecuredareas,suchaslockedclosetsordatacenters
(serverrooms),because theyholdanorganization'smostvaluable data anddonothaveto
be accessed by operators on a continuous basis. The rest of the computers on the network
function as
clients
(see
Figure 17.1
).
Figure 17.1
The components of a client/server LAN.
