Cisco Catalyst 4500 series Administration Manual page 649

Chapter 22 Configuring STP and MST
Timers:hello 0, topology change 0, notification 0, aging 300
Port 323 (FastEthernet6/3) of VLAN1 is forwarding
Port path cost 19, Port priority 128, Port Identifier 129.67.
Designated root has priority 32768, address 0001.6445.4400
Designated bridge has priority 32768, address 0001.6445.4400
Designated port id is 129.67, designated path cost 0
Timers:message age 2, forward delay 0, hold 0
Number of transitions to forwarding state:1
BPDU:sent 3, received 91
Port 324 (FastEthernet6/4) of VLAN1 is blocking
Port path cost 19, Port priority 128, Port Identifier 129.68.
Designated root has priority 32768, address 0001.6445.4400
Designated bridge has priority 32768, address 0001.6445.4400
Designated port id is 129.68, designated path cost 0
Timers:message age 2, forward delay 0, hold 0
Number of transitions to forwarding state:0
BPDU:sent 1, received 89
You can set the switch as the root:
Switch# configure terminal
Switch(config)# spanning-tree vlan 1 root primary
Switch(config)# spanning-tree vlan 1 root primary
VLAN 1 bridge priority set to 8192
VLAN 1 bridge max aging time unchanged at 20
VLAN 1 bridge hello time unchanged at 2
VLAN 1 bridge forward delay unchanged at 15
Switch(config)# end
This configuration is the one after the switch becomes the root:
Switch# show spanning-tree vlan 1
VLAN1 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 8192, address 0030.94fc.0a00
Configured hello time 2, max age 20, forward delay 15
We are the root of the spanning tree
Topology change flag set, detected flag set
Number of topology changes 3 last change occurred 00:00:09 ago
Times: hold 1, topology change 35, notification 2
Timers:hello 0, topology change 25, notification 0, aging 15
Port 323 (FastEthernet6/3) of VLAN1 is forwarding
Port path cost 19, Port priority 128, Port Identifier 129.67.
Designated root has priority 8192, address 0030.94fc.0a00
Designated bridge has priority 8192, address 0030.94fc.0a00
Designated port id is 129.67, designated path cost 0
Timers:message age 0, forward delay 0, hold 0
Number of transitions to forwarding state:1
BPDU:sent 9, received 105
Port 324 (FastEthernet6/4) of VLAN1 is listening
Port path cost 19, Port priority 128, Port Identifier 129.68.
Designated root has priority 8192, address 0030.94fc.0a00
Designated bridge has priority 8192, address 0030.94fc.0a00
Designated port id is 129.68, designated path cost 0
Timers:message age 0, forward delay 5, hold 0
Number of transitions to forwarding state:0
BPDU:sent 6, received 102
Switch#
OL-27597-01
hello 2, max age 20, forward delay 15
Software Configuration Guide—Release IOS XE 3.5.0SG and IOS 15.2(2)SG
Configuring STP
22-11