WAN - Wide Area Network

What is a WAN?

A network spanning large geographical areas - across cities, countries, or even continents. WANs connect multiple LANs together over long distances.

Key Characteristics:

• Geographic spread: Cities, countries, continents - potentially worldwide
• Coverage area: Unlimited - can span entire planet
• Ownership: Uses third-party telecommunications infrastructure
• Infrastructure: Relies on telecoms companies (BT, Virgin, Vodafone) for cables, fiber, satellites
• Speed: Slower than LAN - typically 10-1000 Mbps (but improving with fiber)
• Connection: Fiber optic cables, telephone lines, satellite links, microwave links
• Latency: Higher (10-100ms+) - data travels hundreds/thousands of miles

Common WAN Examples:

• The Internet: The world's largest WAN, connecting billions of devices globally
• Corporate WAN: Multinational company linking offices in London, New York, Tokyo
• Banking network: Bank's ATMs and branches connected nationwide
• Mobile networks: 4G/5G networks operated by Vodafone, EE, O2
• Cloud services: AWS, Azure, Google Cloud connecting data centers worldwide

Typical WAN Components:

• Fiber optic cables: High-speed undersea and underground cables
• Satellites: For remote areas or global coverage
• Telephone lines: Older copper infrastructure (ADSL, DSL)
• Routers: Specialized WAN routers at connection points
• Leased lines: Dedicated connections rented from telecoms providers