A Wide Area Network (WAN) is a computer network that spans a large geographic area, such as a city, a country, or even the world. WANs are used to connect computers and other devices in different locations, allowing them to communicate and exchange data. There are several different technologies and protocols that can be used to build a WAN, including leased lines, satellite links, and the Internet.
One example of a WAN is a company's internal network, which might be used to connect all of its offices and branches in different cities or countries. For example, a global corporation might have offices in New York, London, and Singapore, and it would need a WAN to allow employees in these different locations to access shared resources, such as databases and file servers.
In this case, the WAN would be made up of a combination of leased lines and the Internet. Leased lines are private, dedicated connections that are leased from a telecommunications provider. They offer a high level of security and can be used to connect two or more locations directly, without relying on the Internet. However, leased lines can be expensive and may not be practical for connecting all of the company's offices.
To connect the remaining locations, the company might use the Internet. The Internet is a global network of interconnected computers and servers that allows people and devices to communicate and exchange data. It is a public network, which means that anyone can use it, but it is also relatively slow and less secure than a leased line.
To securely connect its offices over the Internet, the company might use a Virtual Private Network (VPN). A VPN is a private network that is built on top of the Internet. It uses encryption to secure the data that is transmitted between the company's offices, making it more difficult for unauthorized users to intercept and read the data.
In this example, the WAN would allow employees in the different offices to access shared resources, such as databases and file servers, and to communicate with each other using email and instant messaging. It would also enable the company to centralize its IT infrastructure, making it easier to manage and maintain.
Overall, a WAN is a powerful tool for connecting computers and devices in different locations, allowing them to communicate and exchange data. It can be used by companies to connect their offices, by government agencies to connect their agencies, and by individuals to connect their home networks.