Cisco Systems RJ-45-to-AUX Viewing the STP Configuration on a Command Line Switch, Root, 215

Viewing the STP Configuration on a Command Line Switch

To view the configuration, you use the same command you use for the Set/Clear command−based switches. However, you will receive much different output. Use this command:

show spantree

The output should look similar to this on your console:

VLAN1 is executing the IEEE compatible Spanning Tree Protocol Bridge Identifier has priority 8192, address 002C.100A.AD51 Configured hello time 2, max age 20, forward delay 15 Current root has priority 8192, address 002C.100A.AD51

Root port is FastEthernet 1/1, cost of root path is 0 Topology change flag not set, detected flag not set

Topology changes 21, last topology change occurred 1d3hl9m59s ago Times: hold 1, topology change 9211

hello 2, max age 20, forward delay 15

Timers: hello 2, topology change 35, notification 2 Port Ethernet 0/5 of VLAN1 is Forwarding

Port path cost 0, Port priority 100

Designated root has priority 8192, address 002C.100A.AD51 Designated bridge has priority 8192, address 002C.100A.AD51 Designated port is Ethernet 0/5, path cost 10

Timers: message age 20, forward delay 15, hold 1

Configuring the STP Root Switch

To configure the switch to become the root bridge, enter the following command in Privileged mode (Table

10.7defines the syntax fields for this command):

set spantree root <vlan> dia <seconds> hello <seconds>

set spantree root 5 dia 3 hello 2

Configuring the STP Secondary Root Switch

To configure the switch to become the secondary root bridge, enter the following Privileged mode command (Table 10.7 defines the syntax fields for this command):

set spantree root secondary <vlan> dia <seconds> hello <seconds>

catalyst5000> (enable) set spantree root secondary 1 dia 3 hello 2 VLAN 1 bridge priority set to 16384.

VLAN 1 bridge max aging time set to 12. VLAN 1 bridge hello time set to 2.

VLAN 1 bridge forward delay set to 9. catalyst5000> (enable)

Table 10.7: Root and secondary bridge configuration command parameters.

Command Parameter	Definition
root	Designates the root switch. The default priority of the root bridge is 8,192.

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