WAN

A WAN (Wide Area Network) is a network that spans multiple locations — typically connecting branch offices to headquarters, or an office to the internet. Your internet connection is a WAN link.

Where a LAN connects devices within one location, a WAN connects locations to each other or to the internet. For most organizations, the WAN is the internet circuit delivered by an ISP — fiber, cable, or dedicated circuits like MPLS.

Multi-site organizations use WAN links to connect branch offices. Traditionally this meant leased lines or MPLS circuits from a carrier — private, reliable, but expensive and inflexible. Modern alternatives:

SD-WAN — software-defined WAN management that can bond multiple cheaper internet connections (fiber + 4G/5G backup) and intelligently route traffic across them, often replacing expensive MPLS at a fraction of the cost.

VPN over internet — an encrypted tunnel over standard internet circuits. Lower cost than dedicated circuits; latency and reliability depend on the underlying internet paths.

WAN links are typically the performance and reliability bottleneck for multi-site organizations. Bandwidth is shared (or you pay more for dedicated), latency is higher than LAN, and failures depend on your ISP rather than your own infrastructure.