WAN stand for Wide Area Network. It is a data communication network that operates beyond the geographic scope of LAN (Local Area Network).
3 Characteristics of WAN
1. It connect devices that are separated by a broader geographical area than a LAN
2. It use Carriers such as phone companies or network providers
3. It use serial connection.
WAN and OSI (Open System Interconnection) Layer
WAN focus on layer 1 which is physical and layer 2 which is data link.
Standard describe how data is encapsulated for transmission to a remote location. Example is frame relay, ATM (Asynchronous Transfer Mode) and HDLC (High Level Data Link Control).
Standard describe how to provide electrical, mechanical and operational connections