Without WANs, LANs would be a series of isolated networks. LANs provide both speed and cost-efficiency for transmitting data over relatively small geographic areas. However, as organizations expand, businesses require communication among geographically separated sites. The following are some examples:
- Regional or branch offices of an organization need to be able to communicate and share data with the central site.
- Organizations need to share information with other customer organizations. For example, software manufacturers routinely communicate product and promotional information to distributors that sell their products to end users.
- Employees who travel on company business frequently need to access information that resides on their corporate networks.
Home computer users also need to send and receive data across increasingly larger distances. Here are some examples:
- Consumers now commonly communicate over the Internet with banks, stores, and a variety of providers of goods and services.
- Students do research for classes by accessing library indexes and publications located in other parts of their country and in other parts of the world.
It is not feasible to connect computers across a country, or around the world, with physical cables. Therefore, different technologies have evolved to support this communication requirement. Increasingly, the Internet is being used as an inexpensive alternative to enterprise WANs. New technologies are available to businesses to provide security and privacy for their Internet communications and transactions. WANs used by themselves, or in concert with the Internet, allow organizations and individuals to meet their wide-area communication needs.