Hrp; Prp - Siemens SIMATIC NET System Manual

2.3.6

HRP

HRP - High Speed Redundancy Protocol
HRP is the name of a redundancy method for networks with a ring topology. The switches
are interconnected via ring ports. One of the switches is configured as the redundancy
manager. The other switches are redundancy clients. Using test frames, the redundancy
manager checks the ring to make sure it is not interrupted. The redundancy manager sends
test frames via both ring ports and checks that they are received at the other ring port. The
redundancy clients forward the test frames.
If the test frames of the redundancy manager no longer arrive at the other ring port of the
redundancy manager due to an interruption, the redundancy manager switches through its
two ring ports and informs the redundancy clients of the change immediately.
Standby redundancy
Standby redundancy is a method with which several rings each of which is protected by HRP
can be linked together redundantly. In the ring, a master/slave device pair is configured and
these monitor each other via their ring ports. If a fault occurs, the data traffic is redirected
from one Ethernet connection (standby port of the master or standby server) to another
Ethernet connection (standby port of the slave).
Requirements
● HRP is supported in ring topologies with up to 50 devices. Exceeding this number of
devices can lead to a loss of data traffic.
● The following devices support HRP:
– SCALANCE X-500
– SCALANCE X-400
– SCALANCE X-300
– SCALANCE X-200
● All devices must be interconnected via their ring ports.
2.3.7

PRP

Parallel Redundancy Protocol (PRP)
The Parallel Redundancy Protocol (PRP) is a redundancy protocol for Ethernet networks. It
is specified in IEC 62439-3.
The areas of application of PRP are distributed applications with high reliability demands that
depend on the high availability of the network. Compared with classic fault-tolerant networks,
bumpless path redundancy is possible with PRP.
PRP has the advantage that it uses parallel, separate networks made up of standard
network components. End devices that use this method are connected to both networks via
Industrial Ethernet
System Manual, 09/2019, C79000-G8976-C242-10
Network structures and network configuration
2.3 Media redundancy
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