What is RSTP?

RSTP, Rapid Spanning Tree Protocol, is a protocol that allows a network to function properly with loops in topology. It is often used together with deliberate redundant connections to end devices, thereby creating what is often referred to as a “self-healing” network.

All Phoenix Contact managed switches support Rapid Spanning Tree to allow the creation of redundant networks that are compatible with the IT department but are also rugged and reliable for use in tough industrial applications.All Phoenix Contact managed switches support Rapid Spanning Tree to allow the creation of redundant networks that are compatible with the IT department but are also rugged and reliable for use in tough industrial applications.Unless an Ethernet network has a solution for “redundancy”, loops are not allowable in the network topology as they can lead to network failure.

Multiple active paths between network devices, i.e., loops in topology, create several problems. First, the MAC address table used by the switch can fail, since the same MAC addresses are seen on multiple ports. Second, a broadcast storm occurs. This is caused by broadcast packets being forwarded in an endless loop between switches. A broadcast storm can consume all available CPU resources and bandwidth, overwhelm network devices and cause them to fail – requiring the user to reboot them in order to recover network operation.

RSTP, Rapid Spanning Tree Protocol, is an OSI layer-2 protocol defined in the IEEE Standard 802.1D. As the name suggests, it creates a spanning tree within a mesh network of connected Ethernet switches, and disables the links which are not part of that tree, leaving a single active path between any two network devices. Rapid Spanning Tree Protocol allows a network design to include spare (redundant) links to provide automatic backup paths if an active link fails, without the danger of loops, or the need for manual enabling/disabling of these backup links.

RSTP is the most widely used & multi-vendor supported Redundancy method and allows a switch to integrate with existing Ethernet systems & IT practices. Unlike proprietary redundancy mechanisms, RSTP's development as an open standard allows users to integrate RSTP supporting switches from multiple vendors into a single redundancy solution. RSTP allows flexible Redundancy for any: Ring, Tree, or combination topologies as they are all supported.