Supported HSR Operational Modes

This chapter provides details about the different HSR operational modes.

The HSR RedBox also records to which ports HSR frames have been sent (by source MAC address and HSR header sequence number).

Duplicate frames will not be forwarded on the same port again. Frames with the same source MAC address as the RedBox will also be dropped as they have returned to the originator.

Mode H (mandatory, default mode): HSR-tagged forwarding

Mode H is the normal operational HSR ring topology mode.

Figure 1. Mode H Topology

Mode N (optional): No forwarding

For Mode N, traffic received on the ring ports is not forwarded to the other ring port. This mode allows HSR network to be built in the same way as PRP networks with double star topology.

Figure 2. Mode N Topology

Mode T (optional): Transparent Forwarding

In Mode T, HSR headers are removed from all frames and duplicates are not discarded.

Mode T allows stand Ethernet equipment to be used to configure the unit as frames with HSR headers are not normally understood and dropped by standard Ethernet equipment.

Figure 3. Mode T Topology

Mode U (optional): Unicast Forwarding

This mode allows nodes on the interlink port (I - Port) to listen to the same unicast messages as less filtering is performed. Note that here unicast frames are treated the same as multicast frames.

Figure 4. Mode U Topology