Siemens SIMATIC RF185C Operating Instructions Manual page 29

With a line/series topology, remember that if the communication connection of a
communication module to the controller is interrupted, the communication connection to all
downstream communication modules is also interrupted.
Figure 5-3
Figure 5-4
Media redundancy
Media redundancy is a function that ensures network and system availability. Redundant
transmission links in the MRP topology ensure that an alternative communication path is
made available if a transmission link fails. To make this possible you need to configure the
communication modules as a client of the Media Redundancy Protocol (MRP) in STEP 7
(Basic / Professional).
MRP is part of PROFINET standardization according to IEC 61158.
SIMATIC RF185C, RF186C, RF188C, RF186CI, RF188CI
Operating Instructions, 04/2020, C79000-G8976-C512-03
Configuration graphic of a star topology
Configuration graphic of a ring topology
Connection
5.1 Network topology
29