WeOSHSR and PRP HowTo guide
This document, being a non-exhaustive guide, outlines some practical examples of how to configure and use High-Availability Seamless Redundancy (HSR) and Parallel Redundancy Protocol (PRP).
For an overview of what HSR/PRP is and how it may be used, refer to:
Westermo RedBox supports the types hsr (HSR-SAN), prp (PRP-SAN),
and hsr-prp (HSR-PRP). Set the RedBox type with the command type.
The ports are automatically selected, as the RedBox has dedicated
ports for A, B, and interlink. The ports are labeled as such on the
front plate.
redbox:/config/hsr-prp-1/#> show Enabled : YES Type : HSR Mode : H Supervision frames : YES Life check interval : 2 s Entry forget time : 6 (640 ms) Node reboot interval : 500 ms Proxy node forget time : 64 s Node forget time : 64 s Port A : ethA Port B : ethB Multicast octet : 00
Basic HSR setup
A basic HSR setup only requires creating an instance of the type.
redbox:/#> config hsr-prp 1 redbox:/config/hsr-prp-1/#> type hsr redbox:/config/hsr-prp-1/#> leave redbox:/#>
Figure 1 shows a basic HSR ring setup. The ring can be expanded with more HSR devices, and provides seamless failover on link failure.
+---------+
| |
| SAN |
| |
+----+----+
|
|
+----I----+
| |
| redbox |
+-----A HSR-SAN B------+
| | | |
| +---------+ |
| |
| |
| +---------+ |
| | | |
+-----A redbox B------+
| HSR-SAN |
| |
+----I----+
|
|
+----+----+
| |
| SAN |
| |
+---------+
Figure 1: Two SAN devices connected redundantly via two HSR-SAN RedBoxes.
HSR-PRP coupling setup
Figure 2 shows a setup with three of the possible RedBox modes. LAN A and LAN B may contain other PRP and non-PRP devices that have redundancy through the ring.
+---------+
| |
| SAN |
| |
+----+----+
|
|
+----I----+
|redbox-1 |
| |
+-----A PRP-SAN B------+
| | | |
| +---------+ |
| |
+~~~~~~~~~~~~+ +~~~~~~~~~~~~+
| | | |
| | | |
| LAN A | | LAN B |
| | | |
| | | |
+~~~~~~~~~~~~+ +~~~~~~~~~~~~+
| |
| |
| |
+-----I---+ +----I----+
|redbox-2 | |redbox-3 |
| | | |
| HSR-PRP A-------------A HSR-PRP |
| | | |
+-----B---+ +----B----+
| |
| +---------+ |
| |redbox-4 | |
+-----A B------+
| HSR-SAN |
| |
+----I----+
|
|
+----+----+
| |
| SAN |
| |
+---------+
Figure 2: A PRP-SAN RedBox connects a SAN redundantly to an HSR ring, with another SAN device attached at the other side of the ring.
Note: The configuration in Figure 2 is not valid if redbox-2 and redbox-3 are PTP Transparent Clocks, as IEC 62439-3:2016 does not specify how a TC should behave in such a situation.
Configure the LAN ID of the HSR-PRP interlink ports with the respective LAN they connect to, and the Net ID (PRP ID) to the same for both because those A and B are associated with each other. The Net ID prevents frames from LAN A from being sent to LAN B, and vice versa.
A completely separate PRP network also connected to the ring must have another Net ID, as those frames may still enter other PRP networks. The standard specifies a total of 6 possible PRP networks in a single topology (values 1-6, HSR-SAN devices like redbox-4 use the value 0, 7 is reserved for future use).
Below is the configuration for each of the devices in Figure 2.
redbox-1:/#> config hsr-prp 1 redbox-1:/config/hsr-prp-1/#> type prp redbox-1:/config/hsr-prp-1/#> leave redbox-1:/#>
redbox-2:/#> config hsr-prp 1 redbox-2:/config/hsr-prp-1/#> type hsr-prp redbox-2:/config/hsr-prp-1/#> lan-id A redbox-2:/config/hsr-prp-1/#> prp-id 1 redbox-2:/config/hsr-prp-1/#> leave redbox-2:/#>
redbox-3:/#> config hsr-prp 1 redbox-3:/config/hsr-prp-1/#> type hsr-prp redbox-3:/config/hsr-prp-1/#> lan-id B redbox-3:/config/hsr-prp-1/#> prp-id 1 redbox-3:/config/hsr-prp-1/#> leave redbox-3:/#>
redbox-4:/#> config hsr-prp 1 redbox-4:/config/hsr-prp-1/#> type hsr redbox-4:/config/hsr-prp-1/#> leave redbox-4:/#>
Multiple rings
Each PRP LAN can connect to multiple rings for more redundancy.
+~~~~~~~+ +~~~~~~~+
| LAN A | | LAN B |
| Net 1 | | Net 1 |
+~~~~~~~+ +~~~~~~~+
| \ / |
| \ / |
| \/ |
| /\ |
| / \ |
| / \ |
+~~~~~~~+ +~~~~~~~+
| | | |
|Ring 1 | |Ring 2 |
| | | |
+~~~~~~~+ +~~~~~~~+
Figure 3: PRP LANs connected to two separate rings.