Enterasys Networks D-Series - Manual (Page 219)

Enterasys D-Series CLI Reference 8-1
8
Spanning Tree Configuration
This chapter describes the Spanning Tree Configuration set of commands and how to use them.
Spanning Tree Configuration Summary
Overview: Single, Rapid, and Multiple Spanning Tree Protocols
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.
RSTP
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.
MSTP
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
For information about... Refer to page...
Spanning Tree Configuration Summary 8-1
Configuring Spanning Tree Bridge Parameters 8-3
Configuring Spanning Tree Port Parameters 8-33
Configuring Spanning Tree Loop Protect Parameters 8-41
Caution: Spanning Tree configuration should be performed only by personnel who are very
knowledgeable about Spanning Trees and the configuration of the Spanning Tree Algorithm.
Otherwise, the proper operation of the network could be at risk.