Administrator Guide

Layer 2 Switching Commands 789
Example
console(config)#spanning-tree vlan 3 max-age 18
spanning-tree vlan root
Use the spanning-tree vlan root primary command to configure the switch to
become the root bridge or standby root bridge by modifying the bridge
priority from the default value to a lower value calculated to ensure the bridge
is the root (or standby) bridge. Use the no form of the command to let the
network elect the root bridge.
Syntax
spanning-tree vlan vlan-list root {primary | secondary}
no spanning tree vlan
vlan-list root
Default Configuration
The default bridge priority value is 32768.
Command Modes
Global Configuration mode
User Guidelines
This command can be configured even if the switch is configured for MST
(RSTP) mode. It is only used when the switch is configured for STP-PV or
RSTP-PV modes.
The logic sets the bridge priority to a value lower (primary) or next lower
(secondary) than the lowest bridge priority for the specified VLAN or a range
of VLANs. This command only applies when STP-PV or RSTP-PV is enabled.
Configuration of the bridge priority is given preference over configuration of
the root primary or root secondary configuration, which is given preference
over the configuration of DirectLink Rapid Convergence.
Example
console(config)#spanning-tree vlan 3 root primary
2CSNXXX_SWUM204.book Page 789 Monday, January 25, 2016 1:25 PM