DIY Local Area Network

Creating your own local area network is easy and can be a rewarding experience. Ethernet networks are particularly easy because it really is as simple as plugging in cables and making sure your client devices like computers are configured correctly.

One of the most commonly used devices in an ethernet network is a switch or hub. Switches or hubs can come in many shapes and sizes ranging from small 5 port units to connect 5 devices together all the way up to 72 plus ports for larger networks. The switches usually used in small office or home networks are simple devices that require no configuration at all and will work when powered up. More complex networks such as Internet Service Providers or large business networks may use more expensive switches manufactured by the likes of Cisco that are managable, that is they are configurable via a web interface or by a command line interface allowing options like VLANS, multilinking and other tasks unnecessary outside of these environments. Switches are not necessary if you are joining two devices together such as networking two computers or connecting your PC to an adsl modem. A crossover cable will perform this task quite affordably. A crossover cable is a network cable that is wired slightly differently to a normal network cable (which is often reffered to as a patch cable) so that the appropriate wires are in the right place for direct communication rather than communicating through a switch. For more than two devices a switch or hub is required so that there is an available port for every computer or device.

When purchasing your switch you will find that there are a number of different speeds that are available. The two most common speeds are 100mbs and 1000mbs as well as the older and obsolete 10mbs speed. This refers to the speed of data transfer in megabits per second that the switch is capable of transmitting. If your computers have 1000mbs network cards in them and they are plugged into a 100mbs switch then the fastest they can transfer data will be 100mbs. The slowest device in the chain will determine your networks speed and carefull selection of components can avoid any chokepoints. Having said that, 100mbs is quite adequate for sharing a printer or an internet connection that is slower than 100mbs and the only advantage you might see on a 1000mbs network is when you are transferring files from one computer to another. Most new computers come with 1000mbs network cards installed in them and it is wise to consult your computers manual or specifications to determine the speed of its NIC. If the speed of your network is not a concern or you simply dont know the speeds of your devices connect it all up anyway, your hardware will negotiate a speed and it will most likely all work anyway.

Many devices such as ADSL or cable modems and wireless routers have switches built into them and they can provide an excellent backbone to your network with a minimal expenditure in equipment. When planning your network consider what objectives you have in mind and purchase your hardware accordingly, if the goal is to share an ADSL internet connection among three computers, one of which has a printer you would like them all to share then three ethernet cables of the appropriate lengths and an ADSL modem with a 4 port switch built in is all thats required.

Connecting it all up

A network cable has a tang on its connector so that when it is pushed into the network card, switch or devices ethernet port the tang locates into a slot that holds it in place. To unplug the cable simply press down on the tang to unseat it from the slot and it will slide out easily.

Physically connecting your computers and devices is as easy as measuring the distance from the computer to the switch and purchasing a network cable that is at least that length. Ethernet cables can be as long as 100m, longer than that and they do not work. A little extra never does any harm as it allows you to move your computer around without stretching the network cable if you need to work on it. When measuring up and laying your cables it is wise to route them around the edge of the walls etc rather than running the cable through the middle of the room where people walk. Although I personally find it amusing when a person or animal trips over a network cable and ends up on the ground underneath the two computers that have been yanked off the desk and landed on them this is not really a safe practice and serious injury can result. Consider routing your cables through walls or at least around the edge of them. Clip them in place so that they cant be moved. If you are very serious about your network consider having a cabler install the network cables within your walls and providing wall points to plug into.

Once you have your cables run and all devices connected together then some configuration of your network may be required. If you have a device that has a DHCP server built into it like an ADSL or cable modem then running your cables may be all thats required. If this sounds like you then try to go to a website (if you have internet access). If you dont have a DHCP server your network may still be quite functional, if no IP address is set windows XP and higher will automatically assign the computer a 169.254.X.X address with a wide netmask that will allow your machines to communicate with each other. Other protocols such as IPX may also function at this point. If not consider going to our configuration tutorials section.