Packet Flow Through Star Topology

Step through hub-and-spoke packet flow, hub bottlenecks, spoke faults, and central failure

animation
star-topology
hub
gateway
networking
intermediate
A guided star topology workbench for seeing how packets move through a central hub, switch, coordinator, or gateway.
Animation Star topology Hub and spoke

Packet Flow Through Star Topology

Step through how packets move through a central hub, switch, coordinator, or gateway. Compare normal forwarding, gateway upload, congestion, a failed spoke, and full hub failure.

StarTopology type
2 link traversalsCurrent path
Hub healthyCentral device
Check hub tableNext check

Goal

Decide what happens to packet delivery when the central device, one spoke, or hub capacity changes.

Try first

Start with Node to Node. Step through source, hub processing, and destination delivery.

Watch

The packet token always uses the central device unless the scenario is a device-to-gateway upload.

Why it matters

Star networks are easy to manage, but the hub is both the control point and the main failure/bottleneck risk.

Traffic scenario

Two end nodes communicate through the central device. This is a two-link traversal path in the star.

Playback

Light: hub queue is short

Packet stages

The source prepares a frame and sends it only to the central device.
Traffic should pass through the central device.Expected behavior
The path is A -> Hub -> D.Observed evidence
Star forwarding is healthy.Working diagnosis

Topology map

Each spoke has one direct link to the central device. Green marks the selected flow, orange marks active or busy hub work, and red marks a failed spoke or failed hub.

selected flow healthy spoke hub busy failed link or hub

Forwarding decision

The source cannot send directly to another spoke. The central device receives and forwards.

Hub metrics

A star is simple because the central device sees all traffic, but that same device can queue, overload, or fail.

Forwarding timeline

A normal node-to-node star exchange crosses the source spoke, central device, then destination spoke.

Beginner ramp

A star is a hub-and-spoke network. Spoke devices do not need direct links to each other because the central device handles the exchange.

What to notice

A failed spoke link usually isolates one device. A failed hub, switch, coordinator, or gateway can stop the entire star.

Layer language

This animation counts link traversals inside the star. IP hop count may differ if the central device is a switch rather than a router.

Best fit
  • Small to medium networks where simple management matters.
  • Smart home hubs, sensor gateways, Ethernet switches, and coordinator-based IoT networks.
  • Use when the central device can be powered, protected, and monitored.
Main risks
  • Central device failure can disconnect all spokes.
  • Central queueing can delay every flow.
  • Port, radio, airtime, or processing capacity limits scalability.
Compared with mesh
  • Star is simpler and easier to troubleshoot.
  • Mesh can provide alternate paths, but routing is more complex.
  • Star often wins for low-cost gateways; mesh wins when path diversity is essential.
Practice 1

Choose Gateway Upload. Why is this one spoke link instead of a node-to-node exchange?

Practice 2

Choose Spoke Link Fault. Which devices still work, and why does the whole network not fail?

Practice 3

Choose Hub Failure. Which evidence proves this is different from a single spoke failure?