Datasheet

Minasi c01.tex V3 - 05/29/2008 9:45pm Page 7
WHAT’S THE POINT OF NETWORKS AND NETWORKING? 7
In some cases, you install optional hardware to make the network perform certain tasks or to add
to the functionality that the network provides.
When PC networks first came into existence, you could find a wide range of distinctly incom-
patible components. Network hardware could use all kinds of odd-sounding technologies such
as Token Ring and ArcNet. (Don’t worry if these technology names are unfamiliar to you, we’ll
discuss them in more detail as the book progresses. For now, all you need to know is that they
provide a kind of physical connection between computers.) Today, most networks rely on Eth-
ernet connections and use standard components. You might have heard that networks are hard
to put together, partly because they really were in the past, but luckily standardization has made
creating a network significantly easier. Here are the common pieces of hardware you find on a
network:
Connector For many people, the lowly connector isn’t even worth mentioning, but you sud-
denly discover the importance of this element when your network is no longer connected and
nothing is apparently wrong. The typical Ethernet connector looks just like a larger version of
the connector for your telephone, as shown in Figure 1.1. In fact, that’s one of the first things
you need to avoid — mistaking the two types of connector. Notice that the RJ45 connector is
larger and that it has 8 pins in it, rather than the 4 or 6 pins of an RJ10, RJ11, or RJ12 connec-
tor used for a telephone. When you plug a connector into a NIC, hub, switch, or router, the
receptacle normally lights up to show you have a good connection. You should look for these
lights when you need to find a loose connection. It’s a bad idea to plug and unplug connec-
tors too often because the connection can become loose and cause you a lot of trouble.
Figure 1.1
Typical Ethernet
connectors. The male
connector appears on
each end of the cable,
while the female
connector appears with
the computer, hub,
switch, router, or other
device connection.
8
Male RJ45 Connector
Typical Ethemet connectors, the male connector appears on each
end of the cable, while the female connector appears with the computer,
hup, switch, router, or other device connection.
Female RJ45 Connector
11
Network Interface Card (NIC) A network interface card (NIC) connects the computer to the
network. It provides all of the hardware features required to make an electrical connection and
perform low-level networking tasks. A NIC won’t provide the connection by itself. Windows
provides software required to make the NIC functional. Most machines today have one or two
NICs supplied with them. You must have one NIC for each connection you want to create.
A machine with two NICs can use one of them to connect to a local network and the other to
connect to the Internet. NICs have specific characteristics — some of which are important for
everyone to know and some of which are only helpful to technicians. The most important NIC
characteristic is its connection speed because the connection speed determines how fast the
NIC can communicate with other machines connected to the network.
Cable A cable provides a physical connection between the NIC contained within the machine
you want to connect to the network and the hub, switch, or router used to distribute signals to
the rest of the network. Cables come in a confusing array of sizes and types. The most impor-
tant characteristic of the cable is the connection speed it supports. You must match the connec-
tion speed of the cable to the NIC. Otherwise, the NIC won’t be able to connect at full speed.
In some special cases, you need cables with other characteristics. For example, if you want to