Lets Network

When you connect 2 or more computers together, you are creating a LAN (Local Area Network).

When you connect a computer to the Internet, you are joining a WAN (Wide Area Network)!

Connecting to other computers.

If you are only connecting 2 computers to share information, this is called a Peer to Peer network and you can do this using one  Ethernet “crossover” cable or you can use a Hub or Switch and 2 cables, no need for crossover. An alternative is to use WiFi and in some cases you can use Bluetooth but Bluetooth isn’t very fast and doesn’t really have the capacity of WiFi.

If you are connecting more than 2 computers, you will need to use a hub or a switch, switch is an Intelligent hub 🙂

With either method you need to manually assign an IP Address* for each device on the same network.

IP address. An IP address is a unique identity, much like your postal address. Each “network device” on any network needs a unique address / identity. The current IPv4 addresses use a dotted quad notation using 32 bits (using 4 groups of 8 bits) to give a unique “identity” for each device on the network. This 32 bit identity is in the form of xxx.xxx.xxx.xxx. e.g. 192.168.124.253, 172.16.2.20 etc.The octets are numbers between 1 & 254 (0 & 255 are not normally used). The complete IP address is made up of the “Network address” and the “Host address“. A “Subnet Mask” is used to identify the network address from the host address  In many cases the “subnet mask” uses 24 bits so the first 3 octets are the “Network address”  e.g. 192.168.124.0 and 172.16.2.0 and  the last octet is the “host address” x.x.x.253 and x.x.x.20

The new IPv6 IP addresses use 128 bits in the hexadecimal format but Google if you want to know more 🙂

However, If you use the router supplied by your ISP, it will normally include a 4 port switch and will have a DHCP server capability built-in. It will automatically assign an IP Address to each device connected so you won’t need to manually assign one.

Basically, when you power up a “network device” and it is part of a network; it sends a message (broadcast) to ask “who am i”. If you have a DHCP server, it will send a response of something like “you are 192.168.2.20” and that IP address will be unique for that network, in this case the “20” will represent the host address.

The IP address is important as is the the SNB (subnet mask). You will also need to know the “Default Gateway”, which is the IP address of the router. For most home routers the IP address of it is often 192.168.0.1 or 192.168.0.254 (the 3rd & 4th octet can be any number between 0 & 255)

Network devices actually communicate at the MAC address level, which is another unique identity. This is hard wired into the NIC (Network Interface Card) but we won’t go there 🙂

You can normally connect up to 4 computers to the ISP Router when using Ethernet cables (or more using a separate switch)  but using WiFi, you can connect (in theory) up to 250! 2 or more computers connected are called a LAN (Local Area Network). It is local because it is local to you and completely separate from the Internet. The LAN is “Private” and the Internet is “Public”. The ISP Router makes this separation by using a basic Firewall called NAT, the router does a lot more but you can read more about NAT and Firewalls on the Security – firewall menu.

Simple Internet connection

At one time, the only way to achieve connecting 2 or more computers together was by using an “Ethernet” cable. For the past 20+ years this cable has consisted of 4 pairs of wires and this is still the most reliable method of connecting (networking) computers together. The cables are often described as CAT 5 & CAT 6 patch cables or just Ethernet cables.

For the past 15+ years or so we have been able to use WiFi to connect our computers together. Many improvements have been made to WiFi and it has become more reliable but because of its popularity, it is sometimes a victim of its success. WiFi (Wireless Fidelity) is just a name coined by someone to describe a “Wireless” (without wire) method of connecting computers using “Radio waves”. Without a doubt, WiFi is so convenient but it does have limitations and due to it being a “Radio Signal”, it does suffer reliability problems. Bluetooth is also a “Radio Signal” but very much shorter range and isn’t generally used for “networking” but it can be!

Simple Internet connection using WiFi.

Connect to the Internet and Join a Wide Area Network a.k.a.WAN.

Once you have connected your computer or computers to the ISP Router, you are connected to the Internet! To browse websites, just open a browser and enter the Website address (a.k.a.the URL). When you connect to the Internet, you can potentially connect to millions of other computers around the world. This outside (public) world can be hostile so you need to protect yourself / your PC..

Creating a Local Area Network (LAN).

These days it is very easy If you make use of the ISP Router and built-in 4 port switch. If you have more than 4 devices that you want to network, add an extra switch with more ports. ( I have a 16 port switch connected to the ISP Gateway / router) Having a LAN, enables you to share printers and exchange information between computers. You could even set up a device for storing your photos, documents and music etc so that all computers on the LAN would be able to access this “resource”.

You could use an additional combined router/ switch/ WAP. This would allow you to create a Guest LAN. All devices connected to the Guest LAN would only be able to access the Internet and NOT your Home LAN.

Diagram below is similar to my set up but doesn’t show the firewall between the ISP gateway / router and the Switch for the “home LAN”

There’s lots of combinations. If you’re having trouble getting the WAP in the right place to get the signal in all rooms, you could use a standalone WAP that can be connected to the 2nd router either by Ethernet or if the 2nd router is also a WAP, you could connect using WiFi (it then becomes a Bridge) You just need to have a think about what you are trying to achieve and be very careful that you don’t open your LAN to the Internet. Lots of info on this site about network and Internet security.

If you’re having problems with WiFi coverage for the whole house, have a look at “Homeplug” a.k.a. Ethernet Over Mains.

© Jeff DVOIT

www.pcjudo.co.uk

www.dvoit.co.uk