DELL N3000 ユーザーズマニュアル

Configuring the Spanning Tree Protocol

In the following diagram of a small 802.1d bridged network, STP is necessary 

to create an environment with full connectivity and without loops.

Assume that Switch A is elected to be the Root Bridge, and Port 1 on Switch 

B and Switch C are calculated to be the root ports for those bridges, Port 2 on 

Switch B and Switch C would be placed into the Blocking state. This creates a 

loop-free topology. End stations in VLAN 10 can talk to other devices in 

VLAN 10, and end stations in VLAN 20 have a single path to communicate 

with other VLAN 20 devices.