The active region-configuration command activates the configuration of a multiple spanning tree (MST) region.
Usage Scenario
Configuring MST region parameters, especially VLAN mapping tables for MST regions, is likely to cause network topology flapping. To reduce network flapping, make sure that newly configured MST region parameters take effect only after the active region-configuration command is run.
Precautions
Before running the active region-configuration command, you are recommended to run the check region-configuration command to check whether the region configurations that have not taken effect are correct. If the region configurations that have not taken effect are correct, run the active region-configuration command.
After the active region-configuration command is run, the configured MST region parameters will take effect and all spanning trees in the MST region will be recalculated.
If the VLAN to be mapped to an MSTP instance is the control VLAN for the SEP segment, the newly configured parameters of the MST region cannot be activated.