H3C Technologies H3C SecPath F1000-E - Manual (Page 113)

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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 MSTP mode:
stp [ instance instance-id ] priority
priority
Use either command.
32768 by default.
CAUTION:
•
After configuring a device as the root bridge or a secondary root bridge, you cannot change the priority
of the device.
• 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.
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.
The regional root bridge always sends a configuration BPDU with 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 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 taking part in spanning
tree calculation, which limits the size of the MST region.
Make this configuration on the root bridge only. All 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:
Step Command Remarks
1. Enter system view. system-view N/A
2. Configure the maximum hops
of the MST region.
stp max-hops hops 20 by default.
Configuring the network diameter of a switched network
Any two terminal devices in a switched network are interconnected through a specific path composed of
a series of devices. The network diameter is the number of devices on the path composed of the most
devices. The network diameter is a parameter that indicates the network size. A bigger network diameter
indicates a larger network size.
To configure the network diameter of a switched network: