Enterasys Networks 1G58x-09, 1H582-xx, E1 Series Spanning Tree Configuration

Matrix E1 Series (1G58x-09 and 1H582-xx) Configuration Guide 6-1

Spanning Tree Configuration

This chapter describes the Spanning Tree Configuration set of commands and how to use them.

The IEEE 802.1D Spanning Tree Protocol (STP) resolves the problems of physical loops in a

network by establishing one primary path between any two devices in a network. Any duplicate

paths are barred from use and become standby or blocked paths until the original path fails, at which

point they can be brought into service.

The IEEE 802.1w Rapid Spanning Protocol (RSTP), an evolution of 802.1D, can achieve much

faster convergence than legacy STP in a properly configured network. RSTP significantly reduces

the time to reconfigure the network’s active topology when physical topology or configuration

parameter changes occur. It selects one switch as the root of a Spanning Tree-connected active

topology and assigns port roles to individual ports on the switch, depending on whether that port is

part of the active topology.

RSTP provides rapid connectivity following the failure of a switch, switch port, or a LAN. A new

root port and the designated port on the other side of the bridge transition to forwarding through an

explicit handshake between them. By default, user ports are configured to rapidly transition to

forwarding in RSTP.

The IEEE 802.1s Multiple Spanning Tree Protocol (MSTP) builds upon 802.1D and RSTP by

optimizing utilization of redundant links between switches in a network. When redundant links

exist between a pair of switches running single STP, one link is forwarding while the others are

blocking for all traffic flowing between the two switches. The blocking links are effectively used