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3 Detailed checklist
Recommendation for MSPS devices
MSPS devices support multiple trust options. Make sure that the "COS" priority is
preferred over "DSCP".
You can find trust options for MSPS in the following menu: "Layer 2 > QoS > QoS
Trust"
•
Set all ports whose traffic includes PROFINET traffic to "Trust COS".
•
If the network receives time-critical IP data traffic such as VoIP, video
streaming, then select the "DSCP (over) COS" setting.
3.11
Redundancy
3.11.1
Ring redundancy
Ring protocols
Many SCALANCE devices support the following two ring protocols:
•
MRP - Media Redundancy Protocol
•
HRP - High Speed Redundancy Protocol
MRP is standardized for PROFINET, allowing compatible devices to be added to
the ring directly.
HRP is a proprietary protocol that is (almost) exclusively limited to SCALANCE X
devices.
Both protocols require a failover time in the event that the connection is interrupted.
The guaranteed maximum times are 200 ms for MRP and 300 ms for HRP. The
higher-level application must be able to handle these brief interruptions during the
switchover.
For devices that communicate via the ring, the response watchdog time in
PROFINET must be larger than the failover time. To achieve a higher response
watchdog time, increase the update time or the number of retries.
If the application does not permit interruptions, you must use a redundancy method
that does not have a failover time.
Examples of interruption-free redundancy protocols include:
•
HSR - High-availability Seamless Redundancy
•
PRP - Parallel Redundancy Protocol
•
MRPD - Media Redundancy for Planned Duplication
HSR and PRP are only available on the SCALANCE X204 RNA devices.
MRPD is common with SIMOTION, SINAMICS and IRT PROFINET devices.
HRP was initially abbreviated as HSR as well.
Since the newer, interruption-free protocol uses the same abbreviation, HSR was
renamed to HRP.
Note
Older firmware versions and manuals for X-200- or X-300 devices still refer to
HSR. In this case, they mean the "High Speed Redundancy Protocol" with a
failover time of 300 ms.
HSR is only available on the SCALANCE X204 RNA.
Checklist
Article ID: 109745536,
V2.0,
05/2022
17
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