Switching · 6 min read
Ring Network Redundancy with ERPS: Keeping Industrial and Campus Networks Online
Learn how ring topologies and ERPS (ITU-T G.8032) protect industrial, utility and campus networks from fibre cuts, with design rules and comparisons with STP/RSTP.
A single fibre cut should never take down a production line, a substation or a city camera network. The most common way to prevent it is a ring topology protected by a fast-recovery protocol such as ERPS (Ethernet Ring Protection Switching, ITU-T G.8032).
Why rings?
In a chain (daisy-chain) topology, one broken link isolates everything beyond it. Connect the last switch back to the first and every switch has two paths. Ethernet cannot run a loop without a control protocol, though, or broadcast storms follow.
How ERPS works
- One link in the ring is designated the Ring Protection Link (RPL) and is normally blocked, which prevents a loop.
- Switches exchange health messages around the ring.
- When a link fails, the switches next to it signal the failure, the RPL is unblocked and traffic flows the other way around the ring.
- ERPS is designed for fast recovery, typically in the order of tens of milliseconds for well-designed rings, much faster than classic Spanning Tree.
ERPS vs STP/RSTP
| STP | RSTP | ERPS | |
|---|---|---|---|
| Topology | Any | Any | Rings |
| Typical recovery | 30–50 s | Around 1 s or more | Tens of ms (design dependent) |
| Standard | IEEE 802.1D | IEEE 802.1w | ITU-T G.8032 |
Design rules
- Keep rings to a sensible size. Very large rings lengthen recovery and fault isolation.
- Use fibre between cabinets for distance and noise immunity, with suitable SFP optics.
- Route the two directions of the ring through physically different paths where possible.
- Pair network redundancy with power redundancy: dual power inputs and proper DIN-rail supplies.
- Monitor ring state with SNMP so a silent failure doesn't leave you unprotected.
Navijin switches with ring protection
ERPS is supported on selected Navijin managed switches, including the industrial GE2224-24P4C2S-L2 and the SG3801 series. Check each datasheet for supported protocols.
Explore industrial Ethernet and critical infrastructure designs.
FAQ
Frequently asked questions
What is ERPS?
ERPS (Ethernet Ring Protection Switching, ITU-T G.8032) is a protocol that prevents loops in ring networks and quickly reroutes traffic when a link fails.
Is ERPS better than spanning tree?
For ring topologies, ERPS typically recovers much faster than STP or RSTP, which is why it is preferred in industrial and utility networks.
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