Configuring A Secondary Root Switch - Cisco Catalyst 3750 Software Configuration Manual

Configuring Spanning-Tree Features
Command
Step 4 show spanning-tree detail
Step 5
copy running-config startup-config
To return to the default setting, use the no spanning-tree vlan vlan-id root global configuration
command.

Configuring a Secondary Root Switch

When you configure the switch as the secondary root, the switch priority is modified from the default
value (32768) to 28672. The switch is then likely to become the root switch for the specified VLAN if
the primary root switch fails. This is assuming that the other network switches use the default switch
priority of 32768 and therefore are unlikely to become the root switch.
You can execute this command on more than one switch to configure multiple backup root switches. Use
the same network diameter and hello-time values that you used when you configured the primary root
switch with the spanning-tree vlan vlan-id root primary global configuration command.
Beginning in privileged EXEC mode, follow these steps to configure a switch to become the secondary
root for the specified VLAN. This procedure is optional.
Command
Step 1 configure terminal
Step 2
spanning-tree vlan vlan-id root secondary
[diameter net-diameter [hello-time
seconds]]
Step 3
end
Step 4 show spanning-tree detail
Step 5
copy running-config startup-config
To return to the default setting, use the no spanning-tree vlan vlan-id root global configuration
command.
Catalyst 3750 Metro Switch Software Configuration Guide
14-16
Purpose
Verify your entries.
(Optional) Save your entries in the configuration file.
Purpose
Enter global configuration mode.
Configure a switch to become the secondary root for the specified
VLAN.
For vlan-id, you can specify a single VLAN identified by VLAN
•
ID number, a range of VLANs separated by a hyphen, or a series
of VLANs separated by a comma. The range is 1 to 4094.
(Optional) For diameter net-diameter, specify the maximum
•
number of switches between any two end stations. The range is
2 to 7.
(Optional) For hello-time seconds, specify the interval in
•
seconds between the generation of configuration messages by
the root switch. The range is 1 to 10; the default is 2.
Use the same network diameter and hello-time values that you used
when configuring the primary root switch. See the
Root Switch" section on page
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Chapter 14 Configuring STP
"Configuring the
14-14.
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