3com 2948-SFP Plus 用户指南

C

HAPTER 11: 

C

ONFIGURING  

S

PANNING

 T

REE

This section contains information for configuring STP. The Spanning Tree 
Protocol (STP) provides tree topography for any arrangement of bridges. 
STP also provides a single path between end stations on a network, 
eliminating loops.

Loops occur when alternate routes exist between hosts. Loops in an 
extended network can cause bridges to forward traffic indefinitely, 
resulting in increased traffic and reducing network efficiency. 

While Classic STP prevents Layer 2 forwarding loops in a general net-
work topology, convergence can take between 30-60 seconds. Rapid 
Spanning Tree Protocol (RSTP) detects and uses network topologies that 
allow a faster STP convergence without creating forwarding loops.

The device supports the following STP versions:

■ 

  Classic STP — Provides a single path between end stations, avoid-

ing and eliminating loops.

■ 

  Rapid STP — Detects and uses network topologies that provide 

faster convergence of the spanning tree, without creating forwarding 
loops. While Classic STP prevents Layer 2 forwarding loops in a gen-
eral network topology, convergence can take between 30-60 seconds. 
Rapid Spanning Tree Protocol (RSTP) detects and uses network topolo-
gies that allow a faster STP convergence without creating forwarding 
loops.

This section contains the following topics:

 

  Viewing Spanning Tree

 

  Defining Spanning Tree

 

  Modifying Spanning Tree