🌍 Wide Area Network (WAN)

🤔 What is a WAN?

A Wide Area Network (WAN) is a network that spans a very large geographical area, such as a state, a country, or even the entire globe. Its primary purpose is to connect multiple smaller networks (like LANs) over long distances.

The Internet is the largest and most famous example of a WAN.

✅ Key Characteristics of a WAN

• Large Geographical Area: A WAN can cover thousands of kilometers, connecting different cities and countries.
• Leased Infrastructure: Unlike a LAN, the communication infrastructure of a WAN (like fiber optic cables, satellite links) is typically owned and managed by third-party telecommunication companies or ISPs. Organizations lease these lines to connect their locations.
• Slower Speeds: Generally, WAN connections are slower than LAN connections due to the vast distances and complex infrastructure the data must travel through.
• Higher Latency: The time delay (latency) for data to travel from one point to another is significantly higher in a WAN compared to a LAN.

🏢 How are WANs Used?

• Connecting Branch Offices: A large organization like the State Bank of India (SBI) uses a private WAN to connect its headquarters with its thousands of branch offices and ATMs across India.
• Internet Access: Internet Service Providers (ISPs) like Jio, Airtel, and BSNL build and manage massive WANs to provide internet connectivity to homes and businesses nationwide.
• Global Services: WANs make global communication possible, enabling everything from international video calls to accessing websites hosted in other countries.

🛰️ Common WAN Technologies

WANs are built using various long-distance communication technologies:

• Leased Lines: A dedicated, private connection (like a fiber optic line) that an organization rents from a telecom provider to connect two or more of its locations.
• MPLS (Multiprotocol Label Switching): A high-performance network technology used by enterprises to create reliable private WANs for carrying data, voice, and video traffic between their offices.
• VPN (Virtual Private Network): Companies often use the public internet to create secure, encrypted “tunnels” between their sites. This is a cost-effective way to build a WAN.
• Satellite Communication: Used to provide network connectivity to very remote areas where laying physical cables is impossible, such as in mountainous regions or for ships at sea.