WAN - Wide Area Network

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A WAN (Wide Area Network) is a communications network that spans a large geographic area such as across cities, states, or countries. WANs often link multiple smaller networks together including local area networks (LANs) or metro area networks (MANs).

Using Internet VPN for Wide Area Networking

Being the world's largest WAN, the Internet can be used for long distance communications just like X.25, Frame Relay or other private networks.

Some companies set up their own private virtual private network (VPN) servers and use VPN connections over the Internet for protected communications between sites.

Although VPNs provide reasonable levels of security for business uses, a public Internet connection does not always provide the predictable levels of performance that a dedicated WAN link can.


Many WANs were built using a technology standard called X.25 starting in the late 1970s. X.25 networks supported automated teller machines, credit card transaction systems, and some of the early online information services such as CompuServe in the U.S. Older X.25 networks ran using 56 Kbps dialup modem connections.

Frame Relay and MPLS

Frame Relay technology was created to simplify X.25 protocols and provide a less expensive solution for wide area networks that needed to run at higher speeds. Frame Relay became a popular choice for telecommunications companies in the United States during the 1990s, particularly AT&T.

Multiprotocol Label Switching (MPLS) was built to replace Frame Relay by improving protocol support for handling of voice and video traffic in addition to normal data traffic. The Quality of Service (QoS) features of MPLS were key to its success. So-called "triple play" network services built on MPLS increased in popularity during the 2000s and eventually replaced Frame Relay.

Using Leased Lines for Wide Area Networking

Many businesses started using leased line WANs in the mid 1990s as the Web and Internet exploded in popularity. T1 and T3 lines are often used to support MPLS or Internet VPN communications.

Metro Ethernet

Long-distance, point-to-point Ethernet links can also be used to build dedicated wide area networks. While much more expensive than Internet VPNs or MPLS solutions, private Ethernet WANs offer very high performance, with links typically rated at 1 Gbps compared to the 45 Mbps of a traditional T1.

Issues with Wide Area Networks

WAN networks are much more expensive than home or corporate intranets.

WANs that cross international and other territorial boundaries fall under different legal jurisdictions. Disputes can arise between governments over ownership rights and network usage restrictions.

Global WANs require the use of undersea network cables to communicate across continent. Undersea cables are subject to sabotage and also unintentional breaks from ships and weather conditions. Compared to underground land lines, undersea cables tend to take much longer and cost much more money to repair.

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