3Com SuperStack 4 Configuration Manual page 236

248 C 10: RSTP C
HAPTER
Set Priority of a
Specified Bridge
Specify the Switch as
Primary or Secondary
Root Bridge
ONFIGURATION
Operation
Cancel the configuration of the STP-Ignored
VLAN
By default, no VLAN is STP-Ignored if STP is enabled on the Switch.
Whether a bridge can be selected as the "root" of the spanning tree depends on
its priority. By assigning a lower priority, a bridge can be artificially specified as the
root of the spanning tree.
You can use the following command to configure the priority of a specified bridge.
Perform the following configurations in System View.
Table 269 Set Priority of a Specified Bridge
Operation
Set priority of a specified bridge
Restore the default priority of specified bridge
Note that if the priorities of all the bridges in the Switching network are the same,
the bridge with the smallest MAC address will be selected as the "root". When
RSTP is enabled, an assignment of a priority to the bridge will lead to recalculation
of the spanning tree.
By default, the priority of the bridge is 32768.
RSTP can determine the spanning tree root through calculation. You can also
specify the current Switch as the root using this command.
You can use the following commands to specify the current Switch as the primary
or secondary root of the spanning tree.
Perform the following configuration in System View.
Table 270 Specify the Switch as Primary or Secondary Root Bridge
Operation
Specify the current Switch as the primary root bridge of the
spanning tree.
Specify the current Switch as the secondary root bridge of the
spanning tree.
Disqualify the current Switch as the primary or secondary root.
After a Switch is configured as primary root bridge or secondary root bridge, you
cannot modify the bridge priority of the Switch.
A Switch can either be a primary or secondary root bridge, but not both of them.
If the primary root of a spanning tree instance is down or powered off, the
secondary root will take its place, unless you configure a new primary root. Of two
or more configured secondary root bridges, RSTP selects the one with the smallest
MAC address to take the place of the failed primary root.
Command
undo stp ignored vlan
Command
stp priority bridge_priority
undo stp priority
Command
stp root primary
stp root secondary
undo stp root
vlan_list