Media redundancy protocol, network
Support for improved stability and runtime loss prevention
Hillscher Offers MRM and MRC Functions for MRP


Hilscher announced on the 14th that its PROFINET IO device and equipment controller products now support the PROFINET Media Redundancy Protocol (MRP). MRP enables the use of ring topologies in PROFINET IO RT (Real-Time) networks and compensates for single-point errors.

The PROFINET protocol offers several technologies that enable system engineers to build deterministic industrial Ethernet networks with high availability and fail-safe functionality. Among them, the ring topology offers fast recovery times of less than 200 ms. Using this in a PROFINET RT network requires MRP.

Devices in a PROFINET RT network are typically configured in linear or star topologies, communicating status, control, and diagnostic information between devices and equipment controllers. However, if a central device fails, the entire network can be severely impacted in the worst-case scenario. Therefore, to ensure network availability, a ring topology, which is not commonly used in Ethernet environments, is often applied as an alternative.

To maintain proper operation, MRP utilizes a Media Redundancy Manager (MRM), which constantly monitors the ring topology. If a network error is registered, it is designed to provide network relocation information to Media Redundancy Clients (MRCs) in a linear topology. All Hilscher PROFINET IO device controllers can act as MRMs in PROFINET IO networks. Furthermore, all PROFINET IO devices include MRC functionality.

When the MRM issues test frames at regular intervals to assess the integrity of the ring network, the MRC forwards the test frames back to the MRM along the ring. If the MRM fails to return the test frames, it interprets this as a network error, notifies all MRCs of the network error, and transmits control data to transition to a linear topology. Furthermore, the MRC detects link state changes using one of its ports and relays these to the MRM, reducing the time it takes for the MRM to detect errors and repairs.