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You can configure a device as the root bridge by setting the device priority to 0. For the device priority
configuration, see "
Configuring the device priority
Configuring the device as the root bridge of a specific
spanning tree
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Configure the device as
the root bridge.
•
In STP/RSTP mode:
stp root primary
•
In PVST mode:
stp vlan
vlan-id-list
root primary
•
In MSTP mode:
stp
[
instance instance-list
]
root
primary
By default, the device is not a
root bridge.
Configuring the device as a secondary root bridge of a
specific spanning tree
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Configure the device as a
secondary root bridge.
•
In
STP/RSTP
mode:
stp root secondary
•
In PVST mode:
stp vlan
vlan-id-list
root secondary
•
In
MSTP
mode:
stp
[
instance instance-list
]
root
secondary
By default, the device is not
a secondary root bridge.
Configuring the device priority
Device priority is a factor in calculating the spanning tree. The priority of a device determines
whether the device can be elected as the root bridge of a spanning tree. A lower value indicates a
higher priority. You can set the priority of a device to a low value to specify the device as the root
bridge of the spanning tree. A spanning tree device can have different priorities in different spanning
trees.
During root bridge selection, if all devices in a spanning tree have the same priority, the one with the
lowest MAC address is selected. You cannot change the priority of a device after it is configured as
the root bridge or as a secondary root bridge.
To configure the priority of the device in a specified MSTI:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Configure the priority of
the device.
•
In STP/RSTP mode:
stp priority priority
•
In PVST mode:
stp
vlan
vlan-id-list
priority priority
•
In MSTP mode:
The default setting is 32768.