1-17
Configuring MST region-related parameters (especially the VLAN mapping table) results in spanning
tree recalculation and network topology jitter. To reduce network topology jitter caused by the
configuration, MSTP does not recalculate spanning trees immediately after the configuration; it does
this only after you perform one of the following operations, and then the configuration can really takes
effect:
z Activate the new MST region-related settings by using the active region-configuration command
z Enable MSTP by using the stp enable command
Two devices belong to the same MST region only when they have the same MST region name, VLAN
mapping table, and MSTP revision level.
Configuration example
# Configure an MST region, with the name being “info”, the MSTP revision level being level 1, VLAN 2
through VLAN 10 being mapped to spanning tree instance 1, and VLAN 20 through VLAN 30 being
mapped to spanning tree 2.
<device> system-view
[device] stp region-configuration
[device-mst-region] region-name info
[device-mst-region] instance 1 vlan 2 to 10
[device-mst-region] instance 2 vlan 20 to 30
[device-mst-region] revision-level 1
[device-mst-region] active region-configuration
# Verify the above configuration.
[device-mst-region] check region-configuration
Admin configuration
Format selector :0
Region name :info
Revision level :1
Instance Vlans Mapped
0 11 to 19, 31 to 4094
1 1 to 10
2 20 to 30
Specifying the Current Device as a Root Bridge/Secondary Root Bridge MSTP can automatically choose a device as a root bridge through calculation. You can also manually
specify the current device as a root bridge by using the corresponding commands.
Specify the current device as the root bridge of a spanning tree
Follow these steps to specify the current device as the root bridge of a spanning tree: