A Wide Area Network (WAN) is a communication network made up of computers that are non-local to one another, exchanging data across a wide area or great distance. The most common example is the Internet, though a WAN need not be global to qualify as a wide area network. Since computer acronyms have become virtual words, the terminology “WAN network” is often used in the public sector, even though redundant. For those new to these acronyms, adding the word “network” can be a reminder of what a WAN is, so while this article uses the common term, the proper term is WAN, pronounced like ran with a “W.”
Computers interoperate on a WAN network by using a set of standards or protocols for communication. Each computer on the WAN is assigned a unique address known as an Internet Protocol (IP) address. When a computer sends a request out on the WAN network, it gets routed to a specific server that hosts the requested information. The server responds by sending the information back to the IP address of the requesting computer.
The architecture of the Internet, the most familiar WAN, is non-centralized by design, making it nearly impossible to destroy. Like a freeway system in a large metropolis, if one freeway or information highway is taken out, data traffic is automatically re-routed around the breakdown through alternate routes. The highways, in the case of the Internet, are actually leased telephone lines and a combination of other technologies and structures including smaller networks that are linked by the WAN network to become part of the whole.
Some examples of smaller networks in the WAN include Municipal Area Networks (MANs), Campus Area Networks (CANs) and Local Area Networks (LANs). MANs provide connectivity throughout a city or regional area for public access to the Internet, while CANs offer connectivity to students and faculty for on-site resources and online access. LANs can be either private or public, but are usually private networks with optional online access. The home or office network is a good example of a LAN.
A LAN can also become a WAN if, for example, a company with headquarters in both Los Angeles and Chicago links their two LANs together over the Internet. This geographic distance would qualify the network as a WAN. The linked LANs can use encryption software to keep their communications private from the public Internet, creating a Virtual Private Network (VPN). This technology of creating a secure, encrypted channel through the Internet to link LANs is sometimes called tunneling.