The core idea
Connections create possibilities.
A network is more than a list of devices. Topology shows how those devices are connected, which routes traffic can take, and where a single broken link can interrupt communication.
The useful mental model is simple: topology is the shape of connectivity, not the application carried over it.
Build the model
Three useful shapes
Star
Devices meet at a central switch. It is easy to extend, but the center is important.
Mesh
Devices have multiple possible paths. Redundancy improves resilience but adds links and complexity.
Ring
Each device connects to neighbors around a loop. Traffic can follow the ring, but a break needs a recovery strategy.
Set the boundary
PAN, LAN, MAN, WAN, and SAN describe scope or purpose.
PAN means Personal Area Network. It connects devices around one person over a very short range, often with Bluetooth, USB, or another personal link. A phone connected to wireless earbuds or a smartwatch is a typical PAN.
LAN means Local Area Network. It is a network operated across a limited place such as a home, office, school, or campus building. Ethernet and Wi-Fi links, switches, and local addresses commonly work together inside a LAN.
A MAN means Metropolitan Area Network. It connects multiple LANs across a city or metropolitan area, usually through infrastructure managed by an organization or provider.
A SAN means Storage Area Network. It is a dedicated high-speed network that gives servers controlled access to shared storage, commonly using Fibre Channel or storage protocols over Ethernet.
A short-range network around one person, connecting personal devices directly or through a small personal hub.
Example: a phone connected to wireless earbuds over Bluetooth.Mini experiment
Break one link
Choose a topology, then simulate one failed link. Notice whether another path remains.
Star selected. The central switch is the shared path.
Knowledge check
Test your topology model
Answer eleven questions. The answer order changes each time.