How the nodes connect is as consequential as the radio they use. Star, mesh, point-to-point and tree each trade range, reliability, power and complexity differently — and the right shape depends on how far you must reach, how long the batteries must last, and how much the link must survive.
Point-to-point is the simplest: two nodes, one dedicated link. It is a backhaul hop or a single sensor-to-base connection — no routing, no sharing, maximum simplicity. Star connects many nodes to one central hub; the nodes never talk to each other, only to the hub. It is the LPWAN and Wi-Fi shape: simple, low-power leaf nodes, but everything depends on the hub and nothing reaches past one hop.
Tree (or cluster-tree) extends a star hierarchically: the hub connects to routers, which connect to leaves, so coverage reaches further than a single star without the full cost of a mesh. Mesh interconnects nodes so traffic can hop many ways to its destination; it reaches far and heals around failures, at the price of complexity and power.
Range. A star reaches one hop; mesh and tree reach as far as nodes can relay. If your coverage exceeds a single radio hop and you cannot add infrastructure, you need multi-hop. Reliability. A star has a single point of failure in its hub, and a tree loses a whole branch if a router dies; a mesh re-routes around a lost node, which is why it dominates where the link must survive.
Power. Star leaf nodes can sleep deeply because they never relay; in a mesh, any node that forwards traffic must stay awake, which is a real battery cost. Complexity. Mesh routing, addressing and management grow with the network and add overhead and latency, while a star or point-to-point stays trivial. There is no universally best topology — only the best fit for the constraints.
The topology usually comes bundled with the protocol. LPWAN (LoRa, Sigfox) and cellular are stars — simple sleepy devices to gateways or base stations. DECT NR+, Zigbee and Thread are meshes — nodes relay and self-heal. Bluetooth is point-to-point or a small star, with Bluetooth mesh for lighting-style networks. A microwave or satellite backhaul is point-to-point.
So choosing a topology and choosing a protocol are often the same decision, made from the same constraints: how far, how reliable, how low-power, how many nodes, and who owns the infrastructure.
Start from the hardest constraint. If battery life dominates and range fits one hop, a star keeps the nodes asleep and simple. If coverage must extend beyond one hop or the link must survive node failures, pay for a mesh. If you need to stretch a star's reach but not a full mesh, a tree is the middle ground. If it is one link between two fixed points, point-to-point and stop.
We design the whole system around that choice: the radio and protocol, the routing and power behaviour of relaying nodes, and the management plane that keeps a growing network healthy — so the topology serves the range, reliability and battery targets instead of fighting them.
Point-to-point (two nodes, one link), star (many nodes to a central hub), tree or cluster-tree (a hierarchy of hubs and routers), and mesh (interconnected nodes with many paths). Each trades range, reliability, power and complexity differently.
In a star, nodes only talk to a central hub and never relay, so they stay simple and low-power but reach only one hop and depend entirely on the hub. In a mesh, nodes relay for each other, so coverage extends multi-hop and the network heals around failures, at the cost of power and complexity.
A star, usually, because leaf nodes never have to relay and can sleep deeply between brief transmissions. In a mesh, any node that forwards traffic must stay awake, which costs battery — so mesh suits mains-powered or frequently-awake nodes better.
A mesh, because it re-routes around a failed node or degraded path, with no single point of failure. A star fails if its hub fails, and a tree loses a branch if a router fails. Mesh reliability is why it is used where the link must survive.
They usually come together. LPWAN and cellular are stars; DECT NR+, Zigbee and Thread are meshes; Bluetooth is point-to-point or a small star; backhaul links are point-to-point. Choosing a protocol often fixes the topology, so the two decisions share the same constraints.
Start from the hardest constraint. If battery life dominates and range fits one hop, use a star. If coverage exceeds one hop or the link must survive failures, use a mesh. A tree extends a star's range without a full mesh; point-to-point is for a single dedicated link.
Matching the topology and protocol to the hardest constraint — and designing the routing and power behaviour around it — is the real work. Tell us the coverage, the battery target and how much the link must survive.