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Beginners
How To Guide
The Basics of Information Technology
Networks
A network is a group or a number of people or things
linked or connected together, either physically or by
association. A Local Area Network (LAN) is common in
business and it serves users within a confined geographical
area.
Networking an office involves each individual piece
of hardware and software - for example your PC's, printers,
fax machine, scanner and phone connection- to be networked
together to pass and share information. Although networking
is traditionally done by physical cabling some LANs
run on radio links without the need for cabling, in
much the same way as cordless phones have removed the
need to be dragging a long telephone line behind you
- you can talk and move around at the same time.
Here's how a basic network could work; if there are
4 people in your office and you are the only person
that has a printer, each time one of your colleagues
wants to print a document they have to email it over
to you or get up from their desk, walk over to you and
hand you a disk to print from. Why not share that printer
with your colleagues by networking the 4 computers together.
Now they can print directly to your printer through
the network without disturbing you or wasting time walking
across the office to give you the disk to print. However
there is a flaw in the above scenario in that the PC,
to which the printer is attached, controls the printer.
This means that the PC must be constantly switched on
for the printer to work. Alternatively, you can have
a printer connected directly to the network by means
of a Network Interface Card [NIC] in exactly the same
way as a PC is linked to the network. In this way, the
printer is independent of all the PCs on the network.
Other hardware and devices that can be shared include
your fax machine, scanner and telephone connection.
Equally, software applications such as your accounts
package e.g. TAS Books /SAGE / Exchequer, can be accessed
across the network. Some applications such ACT, a customer
contact management package, work best when used in a
network environment.
A hub can act as the central contact point, connecting
to the network interface cards of each device [PC or
printer] on the network and distributing the information
across the network.
In terms of Internet access, to send and receive external
email and surf the Internet you need a router, which
acts as the buffer between your network and the outside
world.
BUS TOPOGRAPHY
However rather than having all the computers or
'workstations' and other hardware connecting to the
hub, you could connect them all by one cable in a ring
or loop where the first computer connects to the next
and so forth until the last computer connects back to
the first. This is described as a BUS type network,
which uses a common pathway between all devices
In a BUS type network all the computers are connected
by one cable where any computer connected can send a
signal down the cable to all the other machines.
The basic components are as follows;
Network Interface Cards
Most PC's now have Network Interface Card's included
therefore they do not have to be bought for the network.
If your PC is not new, you may need to purchase a Network
Interface Card [NIC].
Hub
Costs can vary depending on the size and demands
of your network.
Router
Prices start at €380 to €500 and can rise
rapidly to over €25,000 for a robust enterprise
wide solution. Cisco is the market leader in hubs and
routers.
Cable
The amount of cable required will depend on the number
of PCs and other hardware being connected and the distance
between each point. Remember the maximum distance between
a PC and the hub is 50m.
Example 1: To network a small office with 4 PCs and
no external access, assuming NIC cards are already included
in your PCs, your expense will be the cost of the cable
and hub.
Example 2: To network the same office with 4 PC's and
external access, only one machine needs to be connected
to the Internet others share from this connection -
this is fairly easy to do with DSL as you can connect
straight to the router which enables all other machines
connected to the same router to share the connection.
Your expense will be the cost of the cable, router,
and the telecommunication cost for DSL.
WIDE AREA NETWORK (WAN)
What if you have a sub office? Why not include them
in your network by building a wide area network? A WAN
requires additional hardware to facilitate the secure
transmission of company information.
For example, the general manager of your regional office
may need access over a telecommunication line to the
head office for central information such as client data,
project and stock status as well as requiring the ability
to send and receive emails internally. Equally, people
at the head office will use this WAN to see and communicate
with the regional office.
For security, a firewall is required to filter data
as it passes over the public network to prevent unsolicited
access.
REMOTE ACCESS
Perhaps you want to work form home once a week but
still want to access files on a PC in the office. This
can be achieved efficiently and cost effectively. One
of the PC's in the office needs a phone line linking
into it. You dial through your home phone line directly
into that PC and the two modems establish a connection.
Once connected you have full access to all the other
PC's and hardware in the office network.
VIRTUAL PRIVATE NETWORK
Perhaps your sales team is geographically dispersed
and need regular access to the company network to process
orders and check stock status.
A Virtual Private Network (VPN) may utilise your existing
network and public networks such as the Internet . For
example a sales representative based in the UK can Telework
from their hotel by dialling in over the Internet to
the office network in Ireland, and work away as if the
user was in the company office. With the remote connection
established, the user has access to everything that
is normally available when sitting at the desk.
To set up a VPN, additional software, hardware and security
is required. However, the savings in the long term could
far outweigh the initial costs that are incurred. For
example, a UK based employee accesses the VPN by making
a local call to an ISP and through that Internet connection
he can access the company office network and other relevant
company information. Because the UK employee is using
a VPN over the Internet , the cost of the connection
is a local call to the ISP instead of an international
call to the head office. Multiply this scenario and
the savings soon become apparent.
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