Glossary · Industrial communication
Media Redundancy Protocol (MRP)
Also known as: MRP
German: Medienredundanzprotokoll (MRP)
In industrial communication, the Media Redundancy Protocol (MRP) is a ring redundancy protocol for Ethernet networks standardized in IEC 62439-2. A media redundancy manager keeps one ring port blocked to avoid loops and opens it when a link or device in the ring fails.
- Industrial communication
- Standards
In one sentence
MRP (IEC 62439-2) provides Ethernet ring redundancy: a manager blocks one port and opens it when the ring is interrupted.
Example
A PROFINET ring of twelve devices uses MRP; when a cable is cut, the manager unblocks its second port and communication resumes within the configured recovery time.
How it applies
- Engineering: One device in the ring is the media redundancy manager (MRM); all others are clients (MRC). IEC 62439-2 specifies maximum recovery times depending on ring size and configuration. Applications must tolerate the brief interruption; for bumpless redundancy other protocols (for example PRP, HSR or PROFINET MRPD) are needed.
- Commissioning: Exactly one manager per ring must be configured, ring ports must be defined on each device, and the ring must be closed only after configuration to avoid loops.
- Operation: A broken ring still works but is no longer redundant. The ring status must be monitored and reported so that the fault is repaired promptly.
- Documentation: The documentation team documents the ring members, the manager, ring ports and the expected recovery time, and explains how operators see that the ring is open.
MRP vs. Rapid Spanning Tree
RSTP works on any meshed topology and is common in IT networks. MRP is limited to rings but offers defined, typically shorter recovery times, which suits automation.