A wide area network (WAN) is a large telecommunications network that consists of a collection of LANs and other networks. WANs generally span a wide geographical area, and can be used to connect cities, states, or even countries.
Although they appear like an up-scaled version of a LAN, WANs are actually structured and operated quite differently. This wide area network tutorial serves to explain how WANs are designed/constructed and why their use is beneficial.
Wide Area Network – Connection Options
“Many WANs are built for one particular organization and are private. Others, built by Internet service providers (ISPs), provide connections from an organization’s LAN to the Internet.” Several options are available for WAN connectivity: leased line, circuit switching, packet switching, and cell relay.
WANs are often built using leased lines. These leased lines involve a direct point-to-point connection between two sites. Point-to-point WAN service may involve either analog dial-up lines or dedicated leased digital private lines.
Analog lines – a modem is used to connect the computer to the telephone line. Analog lines may be part of a public-switched telephone network and are suitable for batch data transmissions.
Dedicated lines – digital phone lines that permit uninterrupted, secure transmission at fixed costs.
At each end of the leased line, a router connects to the LAN on one side and a hub within the WAN on the other. Leased lines can get pretty expensive in the long run.
Instead of using leased lines, WANs can be built using circuit switching. “In telecommunications, a circuit switching network is one that establishes a circuit (or channel) between nodes and terminals before the users may communicate, as if the nodes were physically connected with an electrical circuit.”
In other words, a dedicated circuit path is created between end points. The best example of this is a dialup connection. Circuit switching is more difficult to setup, but it does have the advantage of being less expensive.
Packet switching is a method that groups all transmitted data together into bits called packets. Devices transport packets via a shared single point-to-point/point-to-multipoint link across a carrier network. Sequences of packets are then delivered over a shared network.
Similar to circuit switching, packet switching is relatively inexpensive, but because packets are buffered and queued, packet switching is characterized by a fee per unit of information, whereas circuit switching is characterized by a fee per time unit of connection time (even when no data is transferred).
Cell relay is similar to packet switching but it uses fixed length cells instead of variable length packets. Data is divided into these cells and then transported across virtual circuits.
This method is best for simultaneous voice and data but can cause considerable overhead.
WANs vs LANs
Depending on the service, WANs can be used for almost any data sharing purpose for which LANs can be used. The most basic uses of WANs are for email and file transfer, but WANs can also permit users to access data remotely.
New types of network-based software used for productivity, like work-flow automation software, can also be used over WANs. This allows workers to collaborate on projects easily, regardless of their location.
Unlike LANs, WANs typically do not link individual computers. WANs link LANs together. They provide communications links over great distances.
The Existence Of WANs
WANs have existed for decades, but new technologies, services, and applications have developed over the years to dramatically increase their effect on business. WANs were originally developed for digital leased-line services carrying only voice (not data).
At first, they connected the private branch exchanges (PBXs) of remote offices of the same company. WANs are still used for voice services, but today they are used more frequently for data and image transmission (like videoconferencing). These added applications have spurred significant growth in WAN usage, primarily because of the surge in LAN connections to the wider networks.
A wide area network allows companies to make use of common resources in order to operate. Internal functions such as sales, production and development, marketing, and accounting can also be shared with authorized locations through this sort of network.
In the event of a problem – say a company facility is damaged from a natural disaster – employees can move to another location and access the network. Productivity is not lost.
The wide area network has made it possible for companies to communicate internally in ways never before possible. Because of WANs, we (the consumers) can enjoy benefits from companies that we wouldn’t have been able to in the past.
What do you think of WANs? What’s next for connectivity? Leave your thoughts, ideas, and comments below.