by A WAN is a network that uses various links – private lines, Multiprotocol Label Switching (MPLS), virtual private networks (VPNs), wireless (cellular), the Internet to connect smaller metropolitan and campus networks in diverse locations into a single, distributed network. The sites they connect could be a few miles apart or halfway around the globe. In an enterprise, the purposes of a WAN could include connecting branch offices or even individual remote workers with headquarters or the data center, in order to share corporate resources and communications.
A wide area network (WAN) is a network that exists over a large-scale geographical area. A WAN connects different smaller networks, including local area networks (LANs) and metro area networks (MANs). This ensures that computers and users in one location can communicate with computers and users in other locations. WAN implementation can be done either with the help of the public transmission system or a private network.
A WAN connects more than one LAN and is used for larger geographical areas. WANs are similar to a banking system, where hundreds of branches in different cities are connected with each other in order to share their official data.
A WAN works in a similar fashion to a LAN, just on a larger scale. Typically, TCP/IP is the protocol used for a WAN in combination with devices such as routers, switches, firewalls and modems.
WAN architecture
Initially, WANs were built with meshed webs of private lines bought from telecommunications carriers, but WAN architectures have advanced to include packet-switched services such as frame relay and ATM as well as MPLS. With these services, a single connection to a site can be connected to many others via switching within service-provider networks. For certain types of traffic, the Internet can also be woven into the mix to provide less expensive WAN connections.
History of WANs
WANs have been around since the early days of computing networks. The first examples of WANs included circuit-switched telephone lines, but advances in technologies now include wireless transmissions and fiber-optic transmissions. Data can also be moved via leased lines, or even via satellite transmission.
As technologies changed, so did transmission rates. The early days of 2400 bps modems evolved to 40 Gbps and 100 Gbps connectivity today. These speed increases have allowed more devices to connect to networks, witnessed by the explosion of computers, phones, tablets and smaller Internet of Things devices.
In addition, speed improvements have allowed applications to utilize larger amounts of bandwidth that can travel across WANs at super-high speed. This has allowed enterprises to implement applications such as videoconferencing and large-file data backup. Nobody would have considered conducting a videoconference across a 28K bps modem, but now workers can sit in a cubicle and participate in a global company meeting via video.
Many WAN links are supplied via carrier services in which customers’ traffic rides over facilities shared by other customers. Customers can also buy dedicated links that nail up circuits point-to-point and are used for just one customer’s traffic. These are typically used for top-priority traffic or delay-sensitive applications that have high-bandwidth needs such as videoconferencing.
Connections between WAN sites may be protected by virtual private networking (VPN) technology that overlays security functions including authentication, encryption, confidentiality and non-repudiation.
WAN Management and optimization
Because data transmission is still reliant on the rules of physics, the greater the distance between two devices, the longer it will take for data to travel between them. The greater the distance, the greater the delay. Network congestion and dropped packets can also introduce performance problems.
Some of this can be addressed using WAN optimization, which makes data transmissions more efficient. This is important because WAN links can be expensive, so technologies have sprung up that reduce the amount of traffic crossing WAN links and ensure that it arrives efficiently. These optimization methods include abbreviating redundant data (known as deduplication), compression, and caching (putting frequently used data closer to the end user).
Traffic can be shaped, giving some applications (such as VoIP) a higher priority over other, less urgent traffic (such as email), which in turn helps improve the overall WAN performance. This can be formalized into quality of service settings that define classes of traffic by the priority each class receives relative to others, the type of WAN connection that each traffic type will travel, and the bandwidth that each receives.
