6. Wide Area Networks (WAN)

A wide area network (WAN) allows widely dispersed computers to be connected as a single network.

The WAN may cover a number of offices within a business. For example an estate agent with branches in a number of towns may have its computers connected as if they were one large wide area network.

The WAN may even be designed to span the world in order to support the offices of an international company. The WAN may connect a single computer, for example a home computer connecting to the internet, or it may connect LANs together as often happens in branches and offices.

The difference between a LAN and WAN is that some kind of external connection is needed to connect the computers together. This link is often a dedicated leased line from a telecom company but it could be other methods as well.

For instance it could make use of the mobile telephone network. It may be microwave towers linking factories in the same country. For world-wide coverage satellite links could be used to connect offices in different countries.

The point is that there must be a method for digital data to be transmitted from one location to another.

The largest wide area network on the planet is the Internet which connects millions of LANs together. The internet is actually a 'network of networks'. Most companies use the services of an Internet Service Provider (ISP) to connect to the internet. A router / modem in the office connects to the ISP router / modem. This allows data to be transferred in the form of email, attachments and other messaging services.