A computer network is a group of computers interconnected by a communication protocol. The main purpose of computer networking is to share resources and information. For example, if the house or office has three computers and one printer, we can share the printer with the three computers using a network. Then we can print from any computer in the network, directly. Or if you have an external hard drive used to support our data, we can send the information from any computer in the network to the same backup’s hard disk. The most common application is the Internet access sharing via a router device, so any computer that connects via a cable or wireless can surf the Web without having to pay for each computer.

The most common types of networks are:

• LAN (Local Area Network) - Local Area Network, is the most common in homes and businesses. Usually all computers and computing devices are connected through structured cabling.

• WLAN (Wireless Local Area Network) - It's the same principle of Local Area Network (LAN), the difference is that computers or devices connect wirelessly via WI-FI, IR, Bluetooth, etc.

• WAN (Wide Area Network) - Wide Area Network is just a much larger network that can cover different areas as a group of buildings, a city or even a group of countries. Such networks require more advanced technologies to achieve connectivity.