Wide area network (WAN)

A Wide Area Network (WAN) is a telecommunications network that spans large geographical areas, often connecting multiple smaller networks such as local area networks (LANs) and metropolitan area networks (MANs). WANs enable organizations, governments, and individuals to communicate, share data, and access resources across cities, countries, or even globally.

Unlike LANs, which operate within a limited area like an office or building, WANs rely on leased communication lines, satellite links, or internet infrastructure to connect distant systems. The internet itself is the largest example of a WAN.

Advanced

WANs operate by linking routers, switches, and transmission media over long distances using technologies like MPLS (Multiprotocol Label Switching), leased lines, or broadband. They often rely on protocols such as TCP/IP for data transmission and routing protocols like BGP (Border Gateway Protocol) for directing traffic between networks.

Advanced WANs incorporate SD-WAN (Software-Defined WAN), which applies virtualization to manage traffic intelligently, improve performance, and reduce costs by leveraging multiple types of connections, including broadband, LTE, and MPLS. Security features such as encryption, firewalls, and intrusion detection are critical in WAN design, given the public nature of many connections.

Relevance

• Connects offices, branches, and remote workers across wide distances.
• Enables global communication and collaboration.
• Provides businesses with secure, scalable networking solutions.
• Supports access to cloud applications and hosted services.
• Forms the backbone of the internet and global commerce.
• Enhances resilience with redundancy and intelligent traffic routing.

Applications

• A multinational company linking headquarters with branch offices worldwide.
• Banks connecting ATMs and transaction systems across regions.
• Universities providing remote campuses access to central servers.
• Retailers connecting point-of-sale systems across locations.
• Governments managing national communications and defense systems.

Metrics

• Network uptime and availability across connected sites.
• Latency and response time between endpoints.
• Bandwidth utilization and throughput.
• Packet loss and error rates during transmission.
• SLA compliance for leased line or MPLS connections.

Issues

• High costs associated with leased lines or dedicated infrastructure.
• Security vulnerabilities from transmitting data across public networks.
• Latency challenges in global communication.
• Complex configuration and management across multiple sites.
• Dependence on service providers for availability and performance.

Example

A global retailer implemented SD-WAN to connect hundreds of stores to its headquarters and cloud applications. This reduced reliance on expensive MPLS circuits, improved application performance, and increased network security, enabling seamless operations across countries.