high availability seamless redundancy (HSR)

High Availability Seamless Redundancy (HSR) is a redundancy method for Ethernet with high availability. Since the HRS protocol offers instant recovery when a failure occurs, it is used in high availability. In other words, anywhere where a network failure must not occur, for example, in applications in the power supply, production or printing industries.

The HSR protocol is a redundancy protocol for station automation standardized under IEC 61850. It is independent of the application protocol used and can be used in most Industrial Ethernet. Typically it is used in ring topologies, where redundant connections to other network structures are possible. In particular, it should be noted that it is related to the Parallel Redundancy Protocol( PRP), because both protocols work with the MAC address.

As far as duplicate detection is concerned, in the HSR method, duplicate detection is performed on each individual frame immediately after the HSR header has been received. Thus, the reception of the entire frame is not waited for, which leads to a reduction in latency. This method is comparable to the cut-through method, where only the first bytes are evaluated.