Glossary · Industrial communication
Ring topology
Also known as: Ring network, Redundant ring
German: Ringtopologie
In communication networks, a ring topology connects each node to exactly two neighbors, so that the nodes form a closed loop. In Industrial Ethernet, rings are used with a redundancy protocol that blocks one link during normal operation and reroutes traffic when a link or node fails.
- Industrial communication
In one sentence
A ring topology connects each node to two neighbors in a closed loop; with a redundancy protocol it tolerates one link failure.
Example
Eight control cabinets are connected in a fiber ring; when a forklift damages one cable, the ring manager reroutes traffic within milliseconds.
How it applies
- Engineering: A ring is essentially a line with its ends connected. Without a redundancy protocol such as Media Redundancy Protocol (MRP), an Ethernet ring creates a loop and a broadcast storm; the protocol must be configured before the ring is closed.
- Operation: After one failure the ring works as a line and is no longer redundant. Ring status must be monitored and repaired promptly.
- Maintenance: Maintenance on one ring segment is possible without stopping communication, as long as the rest of the ring is intact.
- Documentation: The documentation team shows the ring in the network drawing, identifies ring ports and the redundancy manager, and explains how operators see an open ring.
Ring topology vs. line topology
A Line topology loses communication behind any failed link. A ring with a redundancy protocol tolerates one failure, at the cost of an extra cable and configuration effort.