Network Topologies
The different shapes a network can be arranged in โ and the trade-offs of each.
What is a Topology?
A network topology is the arrangement or layout of how devices (nodes) are connected to each other โ think of it as the 'shape' of the network, whether physical (actual cable layout) or logical (how data actually flows, regardless of physical wiring).
Bus Topology
All devices connect to a single central cable (the 'bus'). It's cheap and simple to set up, but if the main cable fails, the ENTIRE network goes down, and performance degrades as more devices are added since they all share the same cable.
Star Topology
All devices connect to a central device (usually a switch or hub), not to each other directly. This is the most common topology in homes and offices today โ if one device's cable fails, only that device loses connection, not the whole network. The downside: if the central switch fails, everything connected to it goes down.
Ring Topology
Each device connects to exactly two others, forming a closed loop โ data travels around the ring in one (or sometimes both) directions until it reaches its destination. It handles data flow predictably, but a single break in the ring can disrupt the entire network (unless it's a dual-ring setup with a backup path).
Mesh Topology
Every device connects directly to every other device. This gives excellent redundancy โ even if several connections fail, data can still find an alternate path. However, it's expensive and complex to wire, since the number of connections grows very quickly as you add more devices (n devices need n*(n-1)/2 connections).
๐ Real-World Use
Your home network is almost certainly a Star topology (all devices connecting to your Wi-Fi router). The internet's core backbone uses something closer to a Mesh topology for reliability โ if one path goes down, data reroutes through another.
๐ก Pro Tip
A classic exam question: 'why is Star topology so popular despite the single point of failure risk?' โ the answer is that isolating failures to ONE device (instead of the whole network, like in Bus or Ring) makes troubleshooting far easier, and modern switches are quite reliable.
๐งช Quick Self-Test
Check what you just learned โ no pressure, just practice.
1. In which topology does a single cable failure bring down the WHOLE network?
2. Which topology offers the most redundancy if multiple connections fail?