Description of functions
User manual 58185_TREE M4/6-TX PN IP20_hdb_en_10
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4.2.2
Operational and data transmission security thanks to MRP
Fundamentals of
MRP
Media Redundancy Protocol (MRP) is a redundancy protocol according to IEC
62439 for highly available networks. This deterministic protocol can be used
to establish ring topologies. Reconfiguration times less than 200 ms are pos-
sible.
A master is required to establish an MRP ring. The PROFINET PLC, for ex-
ample, can assume the master function.
New PROFINET devices have internal MRP client functions.
MRP compared to RSTP
The recovery times in case of interrupted topology are defined in the MRP
(less than 200 ms due to the deterministic design). MRP is therefore suitable
for critical applications. Compared with RSTP, the configuration effort is lower.
An MRP master device is required to establish MRP rings. Network or tree
structures cannot be realized with MRP.
Rules
In the ring topology, there is an MRP master acting as a redundancy manager.
All other devices in this ring have to be configured as clients. The switch can
be configured either as an MRP client or an RSTP user. Simultaneous use of
both standards is not provided for.
NOTICE
It is not possible to configure the MRP ports via the web server of the switch.
There are no default ports.
Practical implementa-
tion
The switches Art. no. 58184, 58185 and 58186 are provided with MRP client
functions. As-delivered, the switches are configured as RSTP users. The
switches can be configured as MRP devices with the respective MRP ports via
a project engineering tool, e.g. the TIA portal. On the switch, RSTP is disabled.
MRP parameters
The following parameters can be set when configuring the MRP:
Status:
The status of the switch is shown here. If the switch is configured as an
MRP client and is provided with MRP frames, the status is active. If not,
the status is inactive.
Domain:
The domain is the name to be assigned to the MRP ring. The domain
name allows for easy allocation of the devices in order to identify the ring
where the switch is used.
Primary port:
The port configured as the primary MRP port is shown on the device. The
functions of the primary and secondary port are identical.
Secondary port:
The port configured as the secondary MRP port is shown on the device.
The functions of the primary and secondary port are identical.
