Network Topology

Network topology is the arrangement of nodes and links — how devices are connected to one another. It comes in two flavours: physical topology (how the cables and devices are actually laid out) and logical topology (how data actually flows, which can differ from the physical wiring). The shape you choose affects cost, performance, and how gracefully the network survives a failure.

In a bus topology, every device taps into a single shared backbone cable. Data sent by one device travels along the backbone and every other device sees it, keeping only the frames addressed to it. It's cheap and simple, but the backbone is a single point of failure — one break and the whole segment goes down.

In a star topology, every device connects to a central hub or switch. All traffic passes through that central device. This is by far the most common layout for modern LANs because a single cable fault only takes down one device — the rest keep working. The trade-off is that the central device becomes the critical component.

In a ring topology, each device connects to exactly two neighbours, forming a closed loop. Data travels around the ring from node to node until it reaches its destination. Ring layouts can be predictable and orderly, but a single break can disrupt the whole loop unless a second, redundant ring is added.

In a full mesh topology, every node connects directly to every other node. This gives the highest reliability — if one link fails, data simply takes another path — and no single point of failure. The catch is cost: the number of links grows rapidly with each new node, so full mesh is reserved for critical infrastructure like network backbones.

A tree topology arranges nodes in a hierarchy — a root device branches to lower levels, like a series of stars connected together. It scales well and is common in large organizations. A hybrid topology simply combines two or more types, for example connecting several star networks along a backbone. Most real-world networks are hybrids.