Network recovery time measurements of RSTP in an ethernet ring topology

There is currently high activity in the area of redundancy for Ethernet networks. A large number of solutions have emerged among the switch manufacturers during the last few years. This has been accompanied by standardization activities in the IEC. This paper looks briefly into industrial requirements on network redundancy and existing solutions with special focus on ring redundancy solutions. The Rapid Spanning Tree protocol (RSTP) is currently the best-performing Ethernet redundancy standard. RSTP is commonly used in meshed topology networks but performance data from use in ring topology networks is very limited. This paper therefore presents new results from experiments with this protocol in a ring network. This helps in determining where RSTP can be used in industrial networks where the ring topology is common.