A brief introduction to High Availability Seamless Redundancy (HSR) and some of its drawbacks : An insight into the functioning of HSR Protocol

High-availability Seamless Redundancy (HSR) is a standard (IEC 62439-3 Clause 5 [1]) which answers to the need for reliable Ethernet. It is suitable for real time applications. This paper describes the working principle of HSR along with some of its drawbacks. Zero recovery time can be achieved in case of a single failure with the help of HSR. Basically HSR works in a ring topology and it can further be extended to many other topologies particularly rings of rings.HSR was originally proposed for use in automation of smart grid electrical substation[9]. Industrial automation, motion control and transportation are some other areas where it can be implemented.