Configuring an MST Region

Multiple Spanning Tree Protocol (MSTP) divides a switching network into multiple MST regions. After a Multiple Spanning Tree (MST) region name, VLAN-to-instance mappings, and a Multiple Spanning Tree Protocol (MSTP) revision number are configured, MST region configuration is complete.

Context

An MST region contains multiple devices and network segments between them. These devices are directly connected and have the same region name, same VLAN-to-instance mapping, same configuration revision number after MSTP is enabled. One switching network can have multiple MST regions and multiple devices can be grouped into one MST region by using MSTP configuration commands.

Two devices belong to the same MST region when they have the same:

Name of the MST region
Mapping between VLANs and Multiple Spanning Tree Instances (MSTIs)
Revision level of the MST region

Do as follows on a device that needs to join an MST region:

Procedure

Configure the name of the MST region.
1. Run system-view
  The system view is displayed.
2. Run stp region-configuration
  The MST region view is displayed.
3. Run region-name name
  The name of the MST region is configured.
4. Run commit
  The configuration is committed.
Configure mappings between MSTIs and VLANs.

You can configure mappings between MSTIs and VLANs in the MST region view or in the VLAN instance view.

Configure mappings between MSTIs and VLANs in the MST region view.
1. Run system-view
  The system view is displayed.
2. Run stp region-configuration
  The MST region view is displayed.
3. Run instance instance-id vlan { vlan-id1 [ to vlan-id2 ] } &<1-10>
  Mappings between an MSTI and VLANs are configured.
  
  A VLAN cannot be mapped to multiple MSTIs. If you map a VLAN that is already mapped to an MSTI, to another MSTI, the original mapping will be canceled.
  
  The vlan-mapping modulo modulo command configures mappings between MSTIs and VLANs based on a default algorithm. However, the mappings configured using this command cannot always meet the actual demand. Exercise caution when using this command.
4. Run commit
  The configuration is committed.
Configure mappings between MSTIs and VLANs in the VLAN instance view.
1. Run system-view
  The system view is displayed.
2. Run vlan instance
  The VLAN instance view is displayed.
3. Run instance instance-id vlan { vlan-id [ to vlan-id ] } &<1-10>
  Mappings between an MSTI and VLANs are configured.
  
  Do not run both the vlan instance command and the stp region-configuration command on the same device. If mappings between MSTIs and VLANs have been configured in the MST region view displayed by the stp region-configuration command, you must delete the configured mappings before using the vlan instance command.
4. (Optional) Run check vlan instance mapping
  The mappings between MSTIs and VLANs are checked.
5. Run commit
  The configuration is committed.
(Optional) Configure the revision level of the MST region.
1. Run system-view
  The system view is displayed.
2. Run stp region-configuration
  The MST region view is displayed.
3. Run revision-level level
  The MSTP revision level of the MST region is configured.
  
  To modify the MSTP revision level of the MST region to which the device belongs, run this command.
4. Run commit
  The configuration is committed.