Cisco WS-C3550-12G Software Configuration Manual page 303

Chapter 10 Configuring STP
Beginning in privileged EXEC mode, follow these steps to configure a switch as the secondary root
switch:
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
Step 5
copy running-config startup-config
To return the switch to its default setting, use the no spanning-tree vlan vlan-id root global
configuration command.
78-11194-03
Purpose
Enter global configuration mode.
Configure a switch as the secondary root switch.
• For vlan-id, the range is 1 to 1005. Do not enter leading zeros.
• (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 seconds; the default is 2
seconds.
Use the same network diameter and hello-time values that you used
when configuring the primary root switch.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Catalyst 3550 Multilayer Switch Software Configuration Guide
Configuring Basic STP Features
10-25