H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 85)

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Step Command Remarks
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
Priority is a factor in spanning tree calculations. 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.
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.
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 BPDUs that it propagates. When the hop count of a BPDU reaches 0, it is discarded by the
device that received it. This prevents devices beyond the reach of the maximum hop from participating in
spanning tree calculation, so the size of the MST region is limited.
Make this configuration on the root bridge only. All the other devices in the MST region use the maximum
hop value set for the root bridge.
To configure the maximum number of hops of an MST region: