Wide Area Network or WAN refers to a network existing over a large geographical expanse. The WAN will connect many small networks which include both metro area networks or MANs and local area networks of LANs. In other words, this means that all users and computers in one region will be able to interact with users and computers in other regions. You can establish WAN using a private network or public transmission system. So, the WAN really works like a banking system in which there are many branches of a bank spread across multiple cities and these have to be linked with each other in order to share official data.
The WAN works very much like the Local Area Network or LAN, except that it is on a much larger scale. You will use the TCP/IP protocols for the WAN along with devices like switches, routers and modems. The Internet is also really a large WAN because it works through multiple ISPs and connects many small LANs and MANs. So, regardless of which networks the WAN connects or how distant these networks may be, the objective is to let different small networks to communicate with each other from various geographical locations.
The different parts of the WAN may be linked through a VPN or Virtual Private Network. This will make way for protected communications among the websites. This is required since data is going to be transferred across the Internet. While VPNs may be able to give the security a business needs, public Internet connections may not be able to guarantee the kind of performance that you can get with dedicated WAN links. So, fiber optic cables have been used for improving communications between WAN links. The only downside of using WANs is that these are much costly than corporate intranet or home intranets. Besides, the WANs which spread across territorial boundaries will also fall under different types of legal jurisdictions. So, disputes between the networks and governments over the ownership rights are quite common.