Wide Area Network (WAN) is a computer network that spans a large geographic area, connecting multiple Local Area Networks (LANs) across cities, states, or even countries. WANs enable organizations to share data, applications, and services over long distances.
A Wide Area Network (WAN) connects multiple Local Area Networks (LANs) across large geographic distances using carrier-based infrastructure or secure internet connections.
What Is a Wide Area Network?
A Wide Area Network (WAN) connects smaller networks together over long distances using service provider infrastructure or private links.
Unlike a Local Area Network (LAN), which is confined to a single building or campus, a WAN can connect:
- Corporate branch offices
- Data centers
- Cloud environments
- Remote users
- International sites
WANs typically rely on carrier technologies such as:
- MPLS (Multiprotocol Label Switching)
- Leased lines
- Broadband Internet
- Fiber circuits
- 5G/LTE connections
- Satellite links
The most well-known WAN in existence is the Internet.
How It Works
A WAN operates by interconnecting routers across geographically dispersed locations.
At a basic level:
- Devices communicate within a LAN.
- Traffic destined for another location is sent to a router.
- The router forwards the traffic across a service provider network.
- The traffic reaches the remote router.
- The remote router delivers the traffic to its local LAN.
WAN communication commonly uses routing protocols such as:
- BGP (Border Gateway Protocol)
- OSPF (Open Shortest Path First)
- EIGRP (Enhanced Interior Gateway Routing Protocol)
Modern WAN architectures may also include:
Encrypted tunnels (IPsec, SSL/TLS)
SD-WAN (Software-Defined WAN)
VPN overlays
Real World Example
Imagine a company with:
- Headquarters in New York
- A branch office in Chicago
- A data center in Texas
Each location has its own LAN.
To allow employees in Chicago to access servers in Texas, the company deploys a WAN connection using:
- MPLS circuits between sites
- Or secure VPN tunnels over the public Internet
The WAN ensures:
Real-time application performance
Secure data transfer
Centralized access to resources
The Big Picture
Wide Area Networks are critical for modern organizations because they:
- Enable remote office connectivity
- Support cloud services and SaaS applications
- Provide business continuity across regions
- Allow centralized management of IT resources
- Facilitate global operations
Without WANs, organizations would be limited to isolated local networks with no large-scale connectivity.
Related Terms
- Local Area Network (LAN)
- Metropolitan Area Network (MAN)
- Software-Defined WAN (SD-WAN)
- Multiprotocol Label Switching (MPLS)
- Border Gateway Protocol (BGP)
