H3C S3600V2 SERIES, Layer 2-Lan Switching Configuration Manual

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Configuring the current device as a secondary root bridge of a
specific spanning tree
To configure the current 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 current
device as a secondary root
bridge.
•
In STP/RSTP mode:
stp root secondary
•
In PVST mode:
stp vlan vlan-list root secondary
•
In MSTP mode:
stp [ instance instance-id ] root secondary
Use one of the
commands.
By default, a device does
not function as a
secondary root bridge.
Configuring the device priority
CAUTION:
•
You cannot change the priority of a device after it is configured as the root bridge or as a secondary root
bridge.
• During root bridge selection, if all devices in a spanning tree have the same priority, the one with the
lowest MAC address will be selected as the root bridge of the spanning tree.
Device priority is a factor in spanning tree calculation. The priority of a device determines whether the
device can be elected as the root bridge of a spanning tree. A lower numeric 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 MSTIs.
To configure the priority of a device in a specified MSTI:
Step Command Remarks
1. Enter system view.
system-view N/A
2. Configure the priority of
the current device.
•
In STP/RSTP mode:
stp priority priority
•
In PVST mode:
stp vlan vlan-list priority priority
•
In MSTP mode:
stp [ instance instance-id ] priority priority
Use one of the commands.
The default setting is
32768.
Configuring the maximum hops of an MST region
By setting the maximum hops of an MST region, you can restrict the region size. The maximum hops
configured on the regional root bridge will be used as the maximum hops of the MST region.
Configuration BPDUs sent by the regional root bridge always have a hop count set to the maximum value.
When a device receives this configuration BPDU, it decrements the hop count by 1, and uses the new hop
count in the BPDUs that it propagates. When the hop count of a BPDU reaches 0, it is discarded by the