If this is a computer related question; a WAN is a Wide Area Network. If you have 2 or more computers in your home or business and they are connected to each other you have a network. This is considered a local area network - LAN.
If you have 2 of these groups of computers in separate locations they are each individual LANs. When you connect the separate LANs together either with dedicated phone lines (like T1) or through the internet using a 'private' (VPN is one type) connection they become a WAN.
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Answer
WANs or Wide Area Network are usually setup in different geographical Locations with the help of certain hardwares such as Router,Gateway and Bridge.
It uses communication switching technique like Circuit,Message and Packet switching to exchange data.
It used certain services to switch data ( exchange of data between nodes) like
PSTN,PSDN,VAS,ISDN or Private Network.
