High-availability seamless redundancy (HSR) is a seamless redundancy protocol for Ethernet networks. HSR provides seamless communication with fault tolerance based on the duplication of every unicast frame sent in a ring topology. HSR is very useful for mission- and time-critical systems such as substation automation systems (SASs). However, the main drawback of HSR is to generate excessively redundant network traffic in HSR networks. This drawback would unnecessarily waste network bandwidth and hence could degrade network performance in HSR networks. Several traffic reduction techniques for HSR networks have been proposed to improve the network performance in the networks. These techniques can be classified into two main groups: traffic filtering-based and dual paths-based techniques. In this chapter, we provide a description and comparison of these HSR traffic reduction techniques. This chapter describes these traffic reduction techniques and compares their network performance. The operations, advantages, and disadvantages of these techniques are investigated and summarized.
Part of the book: Broadband Communications Networks