16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series
Configuration Tasks
67
Cisco IOS Release 12.2(2)XT, 12.2(8)T, and 12.2(15)ZJ
Configuring Spanning Tree
•
Enabling Spanning Tree, page 67
•
Configuring Spanning Tree Port Priority, page 68
•
Configuring Spanning Tree Port Cost, page 68
•
Configuring the Bridge Priority of a VLAN, page 69
•
Configuring the Hello Time, page 70
•
Configuring the Forward-Delay Time for a VLAN, page 70
•
Configuring the Maximum Aging Time for a VLAN, page 70
•
Configuring BackboneFast, page 71
•
Disabling Spanning Tree, page 72
Enabling Spanning Tree
You can enable spanning tree on a per-VLAN basis. The switch maintains a separate instance of
spanning tree for each VLAN (except on VLANs on which you disable spanning tree).
To enable spanning tree on a per-VLAN basis, use the following commands in global configuration
mode:
Verify Spanning Tree
Step 1
Use the show spanning-tree vlan command to verify spanning tree configuration:
Router#
show spanning
-
tree vlan 200
VLAN200 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address 0050.3e8d.6401
Configured hello time 2, max age 20, forward delay 15
Current root has priority 16384, address 0060.704c.7000
Root port is 264 (FastEthernet5/8), cost of root path is 38
Topology change flag not set, detected flag not set
Number of topology changes 0 last change occurred 01:53:48 ago
Times: hold 1, topology change 24, notification 2
hello 2, max age 14, forward delay 10
Timers: hello 0, topology change 0, notification 0
Port 264 (FastEthernet5/8) of VLAN200 is forwarding
Port path cost 19, Port priority 128, Port Identifier 129.9.
Designated root has priority 16384, address 0060.704c.7000
Designated bridge has priority 32768, address 00e0.4fac.b000
Designated port id is 128.2, designated path cost 19
Timers: message age 3, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 3, received 3417
Command
Purpose
Step 1
Router(config)#
spanning
-
tree vlan
vlan-id
Enables spanning tree on a per-VLAN basis.
Step 2
Router(config)#
end
Exits configuration mode.