Cisco Catalyst 4500 Series Configuration Guide

20-11
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
OL-25340-01
Chapter 20 Configuring STP and MST
Configuring STP
VLAN1 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address 0030.94fc.0a00
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address 0001.6445.4400
Root port is 323 (FastEthernet6/3), cost of root path is 19
Topology change flag not set, detected flag not set
Number of topology changes 2 last change occurred 00:02:19 ago
from FastEthernet6/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
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
hello 2, max age 20, forward delay 15
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

Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E