Spanning Tree Protocol (Stp); Introduction; Configuring And Debugging Stp - Nokia ESB26 User Manual

12. Spanning Tree Protocol (STP)

Introduction

The Spanning Tree Algorithm and Protocol are part of the ANSI/IEEE Std 802.1D MAC
Bridges specifications sponsored by the LAN/MAN Standards Committee of the IEEE
Computer Society.
STP (Spanning-Tree Protocol) provides fault tolerance on networks, by allowing you to
implement parallel paths for network traffic. The algorithm creates a spanning tree (a loop-
free subset of the network topology), that enables a learning bridge to dynamically work
around loops in a network topology. STP allows you to implement redundant paths that are
enabled only when the main paths fail.
STP configuration is disabled by default.

Configuring and Debugging STP

You can use STP configuration commands per switch or per interface. To enable per-switch
STP configuration commands, you must enter Protocol Configuration mode, by using the
following command in global Configuration mode:
device-name(config)#protocol
device-name(cfg protocol)#
The prompt-line indicates Protocol Configuration mode.
(cfg protocol)#
To access the STP interface configuration commands, use the following command in global
Configuration mode:
device-name(config)#interface UU/SS/PP
device-name(config-if UU/SS/PP)#
Argument Description
UU/SS/PP Unit, slot and port number of an interface (i.e. – 1/1/8).
The prompt-line indicates interface UU/SS/PP Configuration
(config-if UU/SS/PP)#
mode.
Table 12-1 summarizes the STP commands available in Protocol Configuration mode.
Table 12-2 summarizes the STP commands available in interface configuration mode.
Table 12-3 summarizes the STP debug commands.
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