3Com WXR100 3CRWXR10095A, WX4400 3CRWX440095A manual Enabling, Spanning Tree, Protocol

352CHAPTER 17: CONFIGURING AND MANAGING SPANNING TREE PROTOCOL

Enabling the	STP is disabled by default. You can enable STP globally or on individual
Spanning Tree	VLANs.
Protocol	To enable STP, use the following command:
	set spantree {enable disable}
	[{all vlan vlan-id port port-list vlan-id}]
	To enable STP on all VLANs configured on a WX switch, type the
	following command:
	WX1200# set spantree enable
	success: change accepted.
	To verify the STP state and display the STP parameter settings, enter the
	display spantree command. For information, see “Displaying Spanning
	Tree Information” on page 361.

Changing Standard You can change the following standard STP parameters:

Spanning Tree „ Bridge priority

Parameters

„Port cost

„Port priority

Bridge Priority The bridge priority determines the WX switch’s eligibility to become the root bridge. You can set this parameter globally or on individual VLANs.

The root bridge is elected based on the bridge priority of each device in the spanning tree. The device with the highest bridge priority is elected to be the root bridge for the spanning tree. The bridge priority is a numeric value from 0 through 65,535. Lower numeric values represent higher priorities. The highest priority is 0, and the lowest priority is 65,535. The default bridge priority for all devices is 32,768.

If more than one device has the highest bridge priority (lowest numeric value), the device with the lowest MAC address becomes the root bridge.

If the root bridge fails, STP elects a new root bridge based on the bridge priorities of the remaining bridges.