Siemens SIMATIC NET System Manual page 87

Topology
The diagram below shows the redundant linking of two MRP rings. In addition, MRP
Interconnection also supports additional topologies which are, however, not supported by the
current firmware.
Figure 2-10
Operating principle
The requirement for MRP Interconnection is that MRP is used in all rings involved. Four
devices are required for the two MRP Interconnection connections:
● One Media Redundancy Interconnection Manager (MIM, shown with a red outline in the
diagram)
● Three Media Redundancy Interconnection Clients (Primary MIC, Primary Coupled MIC
and Secondary Coupled MIC)
Because each device is part of an MRP ring, each device also takes on one of the roles
defined for MRP, i.e. MRC or MRM.
Industrial Ethernet
System Manual, 09/2019, C79000-G8976-C242-10
Redundant connection of two MRP rings with MRP Interconnection
Network structures and network configuration
2.3 Media redundancy
87