Field Guide · concept

Also known as: local area network, wide area network

A LAN (local area network) covers a small area such as a home, office, or building, while a WAN (wide area network) spans long distances and ties many networks together — the internet being the largest WAN of all.12

devices switch router internet LAN (one site) WAN
Within one site, devices reach a switch and share a single subnet — that is the LAN. The router at the edge is the gateway: its inside face joins the LAN, its outside face reaches across the WAN to other networks and the internet.

Overview

A LAN connects nearby devices over Ethernet and Wi-Fi, usually through a switch and a single IP subnet, giving high speed and low latency within one site. Because every device is close and under one administration, a LAN can run fast and cheap, and traffic between two local machines never has to leave the building.

A WAN links such sites across cities or continents over leased lines, fiber, or the public internet, at greater distance but typically lower speed and higher latency than a LAN. The boundary between them is a router acting as the gateway: the LAN side faces inward toward local devices, the WAN side faces out toward the wider network.

The distinction is one of scope, not of any single technology — the same Ethernet and IP that run a LAN also carry WAN traffic — and it governs where you put fast local links versus slower, costlier long-haul ones.

LAN vs WAN

The two differ mainly in reach, and everything else follows from that:

Trait LAN WAN
Span One site or building Cities to continents
Speed High (1–100 Gb/s) Often lower, varies
Latency Very low Higher
Owned by You / one organization Carriers, shared
Example Office network The internet

Where it fits

The LAN-versus-WAN distinction shapes how a distributed system is laid out. A GopherTrunk site keeps its capture nodes and storage server on a fast local LAN, then reaches across the WAN only to publish results or pull in remote feeds — keeping the bandwidth-heavy raw IQ data local and sending just the compact decoded output over the slower, costlier wide-area link. Getting that split right is the difference between a responsive multi-node site and one that saturates its uplink.

Sources

  1. Local area network — Wikipedia, on networks covering a small area. ↩

  2. Wide area network — Wikipedia, on networks spanning long distances. ↩

See also