Wide Area Networks (WANs)

Wide Area Networks (WANs)

A wide area network (WAN) interconnects LANs. A WAN may be located entirely within a state or country, or it may be interconnected around the world.

WANs are characterized by the following:

They exist in an unlimited geographical area.
They are more susceptible to errors due to the distances data travels.
They interconnect multiple LANs.
They are more sophisticated and complex than LANs.
Their technology is expensive.

WANs can be further classified into two categories: enterprise WANs and global WANs. An enterprise WAN is a WAN that connects the widely separated computer resources of a single organization. An organization with computer operations at several distant sites can employ an enterprise WAN to interconnect the sites. An enterprise WAN can use a combination of private and commercial network services but is dedicated to the needs of a particular organization. A global WAN interconnects networks of several corporations or organizations. An example of a global WAN is the Internet.

WANs are often a natural outgrowth of the need to connect geographically separate LANs into a single network. For instance, a company might have several branch offices in different cities. Every branch would have its own LAN so that branch employees could share files and other resources, and all the branches together would be part of a WAN, a greater network that enables the exchange of files, messages, and application services between cities.

Much of the complexity and expense of operating a WAN is caused by the great distances that the signal must travel to reach the interconnected segments. WAN links are often slower and typically depend on a public transmission medium leased from a communications service provider.