Chapter 13 Stp Commands; Spanning Tree Domains - Extreme Networks ExtremeWare Command Reference Manual

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STP Commands

This chapter describes:

• Commands related to creating, configuring, enabling, and disabling Spanning Tree Protocol (STP) on

• Commands related to enabling and disabling Rapid Spanning Tree Protocol (RSTP) on the switch

• Commands related to displaying and resetting STP settings on the switch

The Spanning Tree Protocol (STP) is a bridge-based mechanism for providing fault tolerance on

networks. STP is a part of the 802.1d bridge specification defined by the IEEE Computer Society. To

explain STP in terms used by the 802.1d specification, the switch will be referred to as a bridge.

STP allows you to implement parallel paths for network traffic, and ensure that:

• Redundant paths are disabled when the main paths are operational.

• A redundant path is enabled if the main path fails.

The Rapid Spanning Tree Protocol (RSTP; 802.1w) provides an enhanced spanning tree algorithm that

improves the convergence speed of bridged networks. RSTP takes advantage of point-to-point links in

the network and actively confirms that a port can safely transition to the forwarding state without

relying on any timer configurations. If a network topology change or failure occurs, RSTP rapidly

recovers network connectivity by confirming the change locally before propagating that change to other

devices across the network. For broadcast links, there is no difference in convergence time between STP

RSTP supersedes legacy STP protocols, supports the existing STP parameters and configurations, and

allows for seamless interoperability with legacy STP.

The switch can be partitioned into multiple virtual bridges. Each virtual bridge can run an independent

Spanning Tree instance. Each Spanning Tree instance is called a Spanning Tree Domain (STPD). Each

STPD has its own root bridge and active path. After an STPD is created, one or more VLANs can be

assigned to it.

A port can belong to multiple STPDs. In addition, a VLAN can span multiple STPDs.

The key points to remember when configuring VLANs and STP are:

• Each VLAN forms an independent broadcast domain.

ExtremeWare Software 7.3.0 Command Reference Guide

Extremeware 7.3.0