Wide Area Network (WAN)


Introduction :
A WAN is a connection of multiple locations to make a single network. WANs connect smaller networks (LANs- local area networks) across long distances. It extends over a large geographical area for the purpose of computer networking. 
WANs are used to connect LANs together so that users and computers located in one area can communicate with the users and computers located in another area. It interconnects connecting devices such as switches, routers or modems. 

Working Principle :
There are two types of WANs: Point-to-point WAN and Switched WAN
  • Point-to-point WAN
A point-to-point WAN contains two connecting devices and a connection medium. They provide basic connectivity between the two devices. 

This kind of point-to-point WAN connection is also called a leased circuit or leased line because it is always available and you have the exclusive right to use it as long as you keep paying for it.
  • Switched WAN 
A switched WAN is a network with more than two ends.

WAN networks work on the principle of  VC (Virtual Circuit) based packet switching. There is a signalling phase and then a data transfer phase.
During the signalling phase, the WAN switches communicate amongst themselves using a signalling protocol to establish a virtual connection between the endpoints that need to communicate. Then comes the data transfer phase - the actual data is then carried in Layer 2 frames with suitable VC Identifiers. 
Also, both Permanent Virtual Circuits and Switched Virtual Circuits are supported by these protocols. While leased lines use PVCs, general connections use SVCs.

Advantages of WANs :

  1. WAN covers a larger geographical area. This makes it easier for business offices situated at longer distances to communicate.
  2. The software files are shared among all the users. This ensures that all the users have access to the latest version of the files, and no previous versions of the files will be used.
  3. WANs facilitate the formation of global integrated networks. It also supports global markets and global businesses.  
  4. Use of WANs Boosts your privacy - setting up a WAN allows you to share sensitive data with all your sites without having to send the information over the Internet
Disadvantages of WANs:
  1. The initial investment costs of using a WAN are higher.
  2. WANs have more security issues as compared to MANs and LANs. WANs have many technologies combined with each other which can create a security gap.
  3. The cost of setting up a WAN is high. Setting up a WAN for the first time in an office is expensive. It may involve purchasing routers, switches, and extra security software.
  4. It is difficult to maintain the network as it requires skilled technicians and network administrators.

Applications of WANs:

  1. The first examples of WANs included circuit-switched telephone lines, but advances in technologies now include wireless transmissions and fibre-optic transmissions.
  2. The best example of WANs being used is that of the Internet. The Internet is the largest WAN which supports thousands of LANs to operate within it and connects users from all across the world.

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