What is WAN (Wide Area Network) in Computer Network?

A Wide Area Network (WAN) is a computer network that connects two or more computers across large geographical distances, spanning cities, countries, or even continents. Unlike LANs, WANs utilize public networks such as telephone systems, microwave broadcasts, or satellite communications for connectivity.

Types of WAN

Enterprise WAN − Connects computers located in different geographical regions belonging to a single organization. Access is restricted to authorized personnel only, providing secure inter-office communication.

Global WAN − Connects different organizations and is accessible to the general public. The Internet is the largest example of a Global WAN, created by interconnecting LANs and MANs worldwide.

WAN Hardware Components

Bridges

A bridge is hardware that connects two or more LANs to form a WAN. Bridges operate at the Data Link Layer of the OSI model and handle traffic flow by learning the addresses of data packets. They work best when connecting LANs using the same network protocol.

Routers

A router connects two or more dissimilar LANs to form a WAN, operating at the Network Layer of the OSI model. Routers can connect LANs using different network protocols and compute the best routes for data packets based on routing protocols.

Common router types include central router, local router, remote router, and peripheral router.

Gateways

A gateway connects two dissimilar LANs with different communication protocols. Operating at the Application Layer of the OSI model, gateways are slower than bridges or routers but provide protocol conversion capabilities through their built-in processors and memory.

Additional Components

Brouter − Combines the functionality of both bridges and routers, capable of routing specific protocols while bridging others.

X.25 − A protocol standard used to connect to Public Packet-switched networks, providing a standardized interface for WAN connections.

WAN vs LAN Comparison

Conclusion

WANs enable long-distance communication between geographically dispersed networks using various hardware components like routers, bridges, and gateways. They form the backbone of global connectivity, with the Internet being the most prominent example of a worldwide WAN infrastructure.