Local Area Networks or LANs are a network of
computers that span a relatively small space. Most LANs are in
an office or home, connecting a series of PCs together. Each
computer on the network is called a node, has its own hardware
and runs its own programs like any normal PC, but they can also
access any other data or devices connected to the LAN. Printers,
modems and other devices can also be separate nodes on a LAN.
Ethernet is a type of LAN. It is more or less a LAN
protocol developed by Xerox Corporation in 1976. The
original supported transfer rates of 10 Mbps. A newer version of
Ethernet, called 100Base-T (or Fast Ethernet), supports data
transfer rates of 100 Mbps.
Wide Area Network or WAN is a network that spans a
larger area. It consists of two or more LANs connected to each
other via telephone lines or some other means of connection.
The Internet is a system of
linked networks that are worldwide in scope and facilitate data
communication services such as remote login, file transfer,
electronic mail, the World Wide Web and newsgroups. With the
meteoric rise in demand for connectivity, the Internet has
become a communications highway for millions of users.
An older, archaic form of network configuration which
differs from Ethernet in that all messages are transferred in a
unidirectional manner along the ring at all times. Data is
transmitted in tokens, which are passed along the ring and
viewed by each device. When a device sees a message addressed to
it, that device copies the message and then marks that message
as being read. As the message makes its way along the ring, it
eventually gets back to the sender who now notes that the
message was received by the intended device. The sender can then
remove the message and free that token for use by others.
A common set of rules and signals the
computers on the network use to communicate. There are many
protocols, here are some common ones:
: Transmission Control Protocol / Internet Protocol. This
was originally developed by the Defense Department of the US
to allow dissimilar computers to talk. Today, as many of us
know, this protocol is used as the basis for the internet.
Because it must span such large distances and cross
multiple, smaller networks, TCP/IP is a routable protocol,
meaning it can send data through a router on its way to its
destination. In the long run, this slows things down a
little, but this ability makes it very flexible for large
Developed by Novell for use with its NetWare NOS, but
Microsoft built compatibility into both NT and Windows 9x.
IPX is like an optimized TCP/IP. It, too, is a routable
protocol, making it handy for large networks, but it allows
quicker access over the network than TCP/IP. The downfall is
that it doesnít work well over analog phone lines. IPX
continually checks the status of transmission to be sure all
the data arrives. This requires extra bandwidth, where
analog phone lines donít have much to begin with. This
results in slow access. Of course, the data is more reliable
: Designed for small LANs, this protocol developed by
Microsoft is quite fast. It lacks the addressing overhead of
TCP/IP and IPX, which means it can only be used on LANs. You
cannot access networks via a router.
For our discussion, we will examine
the two primary types of network architecture:
With this networking configuration, there is no
server, and computers simply connect with each other in a
workgroup to share files, printers, and Internet access. This is
most commonly found in home configurations, and is only
practical for workgroups of a dozen or less computers.
Typically, this network consists of one PC designated
as the server and other PCs connected to the server using the
central data stored on the server. The server provides
more security, preventing the client PCs from accessing one and
other. The server typically can provide access to a
central printer and Internet access, (including e-mail), and
file sharing, This is most commonly found in corporate
configurations, where network security is essential.