Basic Principles of Networking

Whether your a home user or a small business, there are many advantages to networking your computers together.
Mainly :
- sharing your internet connection
- sharing your documents, photos, music files
- sharing your printers

What you will need :

	Two or more computers or laptops.
	A network card (NIC : Network Interface Card) per computer / laptop. Most computers / laptops today come with one already installed on the motherboard. Check the back of the computer and see if theres a square slot similar to a telephone socket with 3 squares joined together
	Cables. CAT5 / CAT5e are generally the norm, though CAT6 is starting to become more available. These are also known as "patch cables" CAT5 runs at a speed of 100Mhz where as CAT6 runs at a higher speed of 500Mhz.
	Hub / Switch. A cable from each computer / laptop plugs into the hub / switch linking all the computers / laptops together. They can be the size of video tape if your linking up to 16 computers or a dvd player if linking up to 128 together.

A basic configuration would be something similar to this.

Computer 1 can be set-up so that its Printer can be shared with computers 2 and 3, so they can print via it saving the need for a printer switch box or multiple printers.
Computer 1 can be set-up so that it can share its Internet connection with computers 2 and 3, so they can all access the web as well as send and receive email.

Warning
For this configuration to work, computer 1 must be switched on and logged in.

Possible alternatives

1. Change your USB ADSL modem for a ADSL Router with built in Hub

Benefit
All computers can now access the internet at anytime without the need for computer 1 to be switched on and logged in.
Some Routers with built in Hub only have around 4 network ports. If you have more computers than the number of network ports, then you can use a hub like so.

Warning
For this configuration to work, the hub must be ‘Auto sensing’ or have a port with an uplink button or you need to use a cross over cable to link the hub and router together.

2. Use a network printer
So far the configurations shown only allow computers 2 and 3 to print when computer 1 is turned on and logged in. By using a network printer attached directly to the router or hub all printers can print at any time.

Many large printers can be purchased with a network option. On HP printers this is determined by the "N" after the printer name i.e. HP4200N. A network card is installed inside the printer already to be configured to connect to the network.

If your printer hasn’t already got a network card installed and you can’t purchase the network card separately, then as an alternative you can now purchase either a USB or parallel print server.
These are an ingenious device which allows you to connect ‘any’ (check on the manufactures website to be sure of compatibility) printer to a network and then set it to be shared with all the computers.

Benefit
Now all computers can print directly to the printer independently of each other.

Its worth considering when using a printer in this way, to load the top tray with plain paper and the second tray with headed paper. That way when printing you can choose the type of paper required without pre-loading the paper each time or worse still somebody else printing on your prepared paper.

Firewalls
You have now seen the various ways of setting up a network but none of these include a firewall.

Without a router
When using a USB ADSL modem attached to one computer which is shared to all the other computers on the network, I would suggest a software firewall.
The firewall software needs to be installed on to all computers on the network. Windows XP comes with its own built in software firewall, however as an extra security I would suggest investing in a 3^rd party firewall just in case.

Be aware that the firewalls need to be configured to allow the other computers on the network access through computer 1 or they won’t be able to access the internet.

With a router
Many of todays routers come with a firewall built in and this is acceptable in most cases where all that is required is to allow computers on the network access to the internet but block all incoming connections.

However if you are considering linking two or more offices together or accessing you home network from elsewhere, then the best option would be a separate firewall.
(Check the software on the router first as you may be able to configured it to allow incoming traffic, in which case a separate firewall is not required)

A separate firewall generally has all the configuration options you would need (and more that you don’t) but basically it needs to be set to allow access to only those users you want to have access and block everybody else.

If you require help with any of these steps or would prefer somebody else to configure a network for you