Glossary · Industrial communication
Star topology
Also known as: Star network, Hub-and-spoke topology
German: Sterntopologie
In communication networks, a star topology connects every node by its own link to a central node, typically a switch, so that all traffic between nodes passes through the center.
- Industrial communication
In one sentence
A star topology connects every node by its own link to a central switch, through which all traffic passes.
Example
In the control cabinet, the PLC, the HMI, a camera and two remote I/O stations are each connected to their own port on a managed switch.
How it applies
- Engineering: Star topologies are the standard in Ethernet and IT networks. Each link is independent, so a single faulty cable or device only affects its own port. Several stars connected together form a tree.
- Diagnostics: Port statistics on a Managed switch show the state of each link separately, which simplifies troubleshooting.
- Operation: The central switch is a single point of failure; critical networks use redundant switches or rings between switches.
- Documentation: The documentation team documents which device is connected to which switch port and labels cables at both ends. In machine documentation, stars in the cabinet are often combined with lines or rings in the field.
Star topology vs. line topology
A star needs more cable but isolates faults. A Line topology saves cable along a machine but makes devices depend on their upstream neighbors.