Example for Configuring MSTP Multi-Process for Layer 2 Single-Access Rings and Layer 2 Multi-Access Rings

Networking Requirements

On a network deployed with both Layer 2 single-access rings and multi-access rings, switches transmit both Layer 2 and Layer 3 services. To enable different rings to transmit different services, configure MSTP multi-process. Spanning trees of different processes are calculated independently.

In Figure 1, both Layer 2 single-access rings and dual-access rings are deployed and switches A and B carry both Layer 2 and Layer 3 services. Switches A and B connected to dual-access rings are also connected to a single-access ring.

In the ring where MSTP multi-process is configured, you are advised not to block the interface directly connected to the root protection-enabled designated port.

Figure 1 MSTP multi-process for Layer 2 single-access rings and multi-access rings

Configuration Roadmap

The configuration roadmap is as follows:

Configure basic MSTP functions, add a device to an MST region, and create MSTIs.
- Each ring can belong to only one region.
- Each CE can join only one ring.
Configure multiple MSTP processes:
1. Create multiple MSTP processes and add interfaces to these processes.
2. Configure a shared link.
Configure MSTP protection functions:
- Configure priorities of MSTP processes and enable root protection.
- Configure shared link protection.
Configure the Layer 2 forwarding function on devices.

Procedure

Configure basic MSTP functions, add devices to an MST region, and create MSTIs.

Configure MST regions and create MSTIs.

# Configure an MST region and create MSTIs on SwitchA.

<HUAWEI> system-view

[HUAWEI] sysname SwitchA

[SwitchA] stp region-configuration

[SwitchA-mst-region] region-name RG1

[SwitchA-mst-region] instance 1 vlan 2 to 100

[SwitchA-mst-region] instance 2 vlan 101 to 200

[SwitchA-mst-region] instance 3 vlan 201 to 300

[SwitchA-mst-region] active region-configuration

[SwitchA-mst-region] quit

# Configure an MST region and create MSTIs on SwitchB.

<HUAWEI> system-view

[HUAWEI] sysname SwitchB

[SwitchB] stp region-configuration

[SwitchB-mst-region] region-name RG1

[SwitchB-mst-region] instance 1 vlan 2 to 100

[SwitchB-mst-region] instance 2 vlan 101 to 200

[SwitchB-mst-region] instance 3 vlan 201 to 300

[SwitchB-mst-region] active region-configuration

[SwitchB-mst-region] quit

Enable MSTP.

# Configure SwitchA.
```
[SwitchA] stp enable
```
# Configure SwitchB.
```
[SwitchB] stp enable
```

Configure multiple MSTP processes.

Create multiple MSTP processes and add interfaces to these processes.

# Create MSTP processes 1 and 2 on SwitchA.

[SwitchA] stp process 1

[SwitchA-mst-process-1] quit

[SwitchA] stp process 2

[SwitchA-mst-process-2] quit

# Create MSTP processes 2 and 3 on SwitchB.

[SwitchB] stp process 2

[SwitchB-mst-process-2] quit

[SwitchB] stp process 3

[SwitchB-mst-process-3] quit

# Add GE 0/0/3 and GE 0/0/4 on SwitchA to MSTP process 1 and GE 0/0/2 to MSTP process 2.

[SwitchA] interface gigabitethernet 0/0/4

[SwitchA-GigabitEthernet0/0/4] stp enable

[SwitchA-GigabitEthernet0/0/4] bpdu enable

[SwitchA-GigabitEthernet0/0/4] stp binding process 1

[SwitchA-GigabitEthernet0/0/4] quit

[SwitchA] interface gigabitethernet 0/0/3

[SwitchA-GigabitEthernet0/0/3] stp enable

[SwitchA-GigabitEthernet0/0/3] bpdu enable

[SwitchA-GigabitEthernet0/0/3] stp binding process 1

[SwitchA-GigabitEthernet0/0/3] quit

[SwitchA] interface gigabitethernet 0/0/2

[SwitchA-GigabitEthernet0/0/2] stp enable

[SwitchA-GigabitEthernet0/0/2] bpdu enable

[SwitchA-GigabitEthernet0/0/2] stp binding process 2

[SwitchA-GigabitEthernet0/0/2] quit

# Add GE 0/0/3 and GE 0/0/4 on SwitchB to MSTP process 3 and GE 0/0/2 to MSTP process 2.

[SwitchB] interface gigabitethernet 0/0/4

[SwitchB-GigabitEthernet0/0/4] stp enable

[SwitchB-GigabitEthernet0/0/4] bpdu enable

[SwitchB-GigabitEthernet0/0/4] stp binding process 3

[SwitchB-GigabitEthernet0/0/4] quit

[SwitchB] interface gigabitethernet 0/0/3

[SwitchB-GigabitEthernet0/0/3] stp enable

[SwitchB-GigabitEthernet0/0/3] bpdu enable

[SwitchB-GigabitEthernet0/0/3] stp binding process 3

[SwitchB-GigabitEthernet0/0/3] quit

[SwitchB] interface gigabitethernet 0/0/2

[SwitchB-GigabitEthernet0/0/2] stp enable

[SwitchB-GigabitEthernet0/0/2] bpdu enable

[SwitchB-GigabitEthernet0/0/2] stp binding process 2

[SwitchB-GigabitEthernet0/0/2] quit

Configure a shared link.

# Configure SwitchA.

[SwitchA] interface gigabitethernet 0/0/1

[SwitchA-GigabitEthernet0/0/1] stp enable

[SwitchA-GigabitEthernet0/0/1] bpdu enable

[SwitchA-GigabitEthernet0/0/1] stp binding process 2 link-share

[SwitchA-GigabitEthernet0/0/1] quit

# Configure SwitchB.

[SwitchB] interface gigabitethernet 0/0/1

[SwitchB-GigabitEthernet0/0/1] stp enable

[SwitchB-GigabitEthernet0/0/1] bpdu enable

[SwitchB-GigabitEthernet0/0/1] stp binding process 2 link-share

[SwitchB-GigabitEthernet0/0/1] quit

Enable the MSTP function in MSTP multi-process.

# Configure SwitchA.

[SwitchA] stp process 1

[SwitchA-mst-process-1] stp enable

[SwitchA-mst-process-1] quit

[SwitchA] stp process 2

[SwitchA-mst-process-2] stp enable

[SwitchA-mst-process-2] quit

# Configure SwitchB.

[SwitchB] stp process 3

[SwitchB-mst-process-3] stp enable

[SwitchB-mst-process-3] quit

[SwitchB] stp process 2

[SwitchB-mst-process-2] stp enable

[SwitchB-mst-process-2] quit

Configure MSTP protection functions.

Configure priorities of MSTP processes and enable root protection.

# Configure SwitchA.

[SwitchA] stp process 1

[SwitchA-mst-process-1] stp instance 0 root primary

[SwitchA-mst-process-1] stp instance 1 root primary

[SwitchA-mst-process-1] quit

[SwitchA] stp process 2

[SwitchA-mst-process-2] stp instance 0 root primary

[SwitchA-mst-process-2] stp instance 2 root primary

[SwitchA-mst-process-2] quit

[SwitchA] interface gigabitethernet 0/0/2

[SwitchA-GigabitEthernet0/0/2] stp root-protection

[SwitchA-GigabitEthernet0/0/2] quit

# Configure SwitchB.

[SwitchB] stp process 3

[SwitchB-mst-process-3] stp instance 0 root primary

[SwitchB-mst-process-3] stp instance 3 root primary

[SwitchB-mst-process-3] quit

[SwitchB] stp process 2

[SwitchB-mst-process-2] stp instance 0 root secondary

[SwitchB-mst-process-2] stp instance 2 root secondary

[SwitchB-mst-process-2] quit

[SwitchB] interface gigabitethernet 0/0/2

[SwitchB-GigabitEthernet0/0/2] stp root-protection

[SwitchB-GigabitEthernet0/0/2] quit

In each ring, the priority of the MSTP process on the downstream CE must be lower than the priority of the MSTP process on the switch.
For switches A and B on the dual-access ring, you are recommended to configure them as the primary root bridges of different MSTIs.

Configure shared link protection.

# Configure SwitchA.

[SwitchA] stp process 2

[SwitchA-mst-process-2] stp link-share-protection

[SwitchA-mst-process-2] quit

# Configure SwitchB.

[SwitchB] stp process 2

[SwitchB-mst-process-2] stp link-share-protection

[SwitchB-mst-process-2] quit

Create VLANs and add interfaces to VLANs.

# Create VLANs 2 to 200 on SwitchA. Add GE 0/0/3 and GE 0/0/4 to VLANs 2 to 100, and add GE 0/0/1 and GE 0/0/2 to VLANs 101 to 200.

[SwitchA] vlan batch 2 to 200

[SwitchA] interface gigabitethernet 0/0/3

[SwitchA-GigabitEthernet0/0/3] port link-type trunk

[SwitchA-GigabitEthernet0/0/3] port trunk allow-pass vlan 2 to 100

[SwitchA-GigabitEthernet0/0/3] quit

[SwitchA] interface gigabitethernet 0/0/4

[SwitchA-GigabitEthernet0/0/4] port link-type trunk

[SwitchA-GigabitEthernet0/0/4] port trunk allow-pass vlan 2 to 100

[SwitchA-GigabitEthernet0/0/4] quit

[SwitchA] interface gigabitethernet 0/0/1

[SwitchA-GigabitEthernet0/0/1] port link-type trunk

[SwitchA-GigabitEthernet0/0/1] port trunk allow-pass vlan 101 to 200

[SwitchA-GigabitEthernet0/0/1] quit

[SwitchA] interface gigabitethernet 0/0/2

[SwitchA-GigabitEthernet0/0/2] port link-type trunk

[SwitchA-GigabitEthernet0/0/2] port trunk allow-pass vlan 101 to 200

[SwitchA-GigabitEthernet0/0/2] quit

# Create VLANs 101 to 300 on SwitchB. Add GE 0/0/3 and GE 0/0/4 to VLANs 201 to 300, and add GE 0/0/1 and GE 0/0/2 to VLANs 101 to 200.

[SwitchB] vlan batch 101 to 300

[SwitchB] interface gigabitethernet 0/0/3

[SwitchB-GigabitEthernet0/0/3] port link-type trunk

[SwitchB-GigabitEthernet0/0/3] port trunk allow-pass vlan 201 to 300

[SwitchB-GigabitEthernet0/0/3] quit

[SwitchB] interface gigabitethernet 0/0/4

[SwitchB-GigabitEthernet0/0/4] port link-type trunk

[SwitchB-GigabitEthernet0/0/4] port trunk allow-pass vlan 201 to 300

[SwitchB-GigabitEthernet0/0/4] quit

[SwitchB] interface gigabitethernet 0/0/1

[SwitchB-GigabitEthernet0/0/1] port link-type trunk

[SwitchB-GigabitEthernet0/0/1] port trunk allow-pass vlan 101 to 200

[SwitchB-GigabitEthernet0/0/1] quit

[SwitchB] interface gigabitethernet 0/0/2

[SwitchB-GigabitEthernet0/0/2] port link-type trunk

[SwitchB-GigabitEthernet0/0/2] port trunk allow-pass vlan 101 to 200

[SwitchB-GigabitEthernet0/0/2] quit

Verify the configuration.

Run the display stp interface brief command on SwitchA.

# GE 0/0/4 is a designated port in the CIST of MSTP process 1 and in MSTI 1.

[SwitchA] display stp process 1 interface gigabitethernet 0/0/4 brief

 MSTID      Port                          Role  STP State       Protection

   0        GigabitEthernet0/0/4          DESI  FORWARDING      NONE
   1        GigabitEthernet0/0/4          DESI  FORWARDING      NONE

# GE 0/0/2 is a designated port in the CIST of MSTP process 2 and in MSTI 2.

[SwitchA] display stp process 2 interface gigabitethernet 0/0/2 brief

 MSTID      Port                         Role  STP State       Protection

   0        GigabitEthernet0/0/2          DESI  FORWARDING      ROOT
   2        GigabitEthernet0/0/2          DESI  FORWARDING      ROOT

Run the display stp interface brief command on SwitchB.

# GE 0/0/4 is a designated port in the CIST of MSTP process 3 and in MSTI 3.

[SwitchB] display stp process 3 interface gigabitethernet 0/0/4 brief

 MSTID      Port                          Role  STP State       Protection

   0        GigabitEthernet0/0/4          DESI  FORWARDING      NONE
   3        GigabitEthernet0/0/4          DESI  FORWARDING      NONE

# GE 0/0/2 is a designated port in the CIST of MSTP process 2 and in MSTI 2.

[SwitchB] display stp process 2 interface gigabitethernet 0/0/2 brief

 MSTID      Port                         Role  STP State       Protection

   0        GigabitEthernet0/0/2          DESI  FORWARDING      ROOT
   2        GigabitEthernet0/0/2          DESI  FORWARDING      ROOT

Configuration Files

Only the MSTP-related configuration files are provided.

SwitchA configuration file

#                                                                               
 sysname SwitchA                                                                
#                                                                               
 vlan batch 2 to 200                                                            
#                                                                               
 stp region-configuration                                                       
  region-name RG1                                                               
  instance 1 vlan 2 to 100                                                      
  instance 2 vlan 101 to 200                                                    
  instance 3 vlan 201 to 300                                                      
  active region-configuration                                                   
#                                                                               
stp process 1                                                                   
 stp instance 0 root primary                                                    
 stp instance 1 root primary                                                    
 stp enable                                                                     
stp process 2                                                                   
 stp instance 0 root primary                                                    
 stp instance 2 root primary                                                    
 stp link-share-protection                                                      
 stp enable                                                                     
#                                                                        
interface GigabitEthernet0/0/1                                                  
 port link-type trunk
 port trunk allow-pass vlan 101 to 200                                          
 stp binding process 2 link-share                                 
#                                                                               
interface GigabitEthernet0/0/2                                                  
 port link-type trunk
 port trunk allow-pass vlan 101 to 200                                          
 stp binding process 2                                                          
 stp root-protection                                                            
#                                                                               
interface GigabitEthernet0/0/3             
 port link-type trunk
 port trunk allow-pass vlan 2 to 100                                            
 stp binding process 1                                                          
#                                                                               
interface GigabitEthernet0/0/4               
 port link-type trunk
 port trunk allow-pass vlan 2 to 100                                            
 stp binding process 1                                                       
#                                                                               
return

SwitchB configuration file

#                                                                               
 sysname SwitchB                                                                
#                                                                               
 vlan batch 101 to 300                                                            
#                                                                               
 stp region-configuration                                                       
  region-name RG1                                                               
  instance 1 vlan 2 to 100                                                      
  instance 2 vlan 101 to 200                                                    
  instance 3 vlan 201 to 300                                                      
  active region-configuration                                                   
#                                                                               
stp process 2                                                                   
 stp instance 0 root secondary                                                  
 stp instance 2 root secondary                                                  
 stp link-share-protection                                                      
 stp enable                                                                     
stp process 3                                                                   
 stp instance 0 root primary                                                    
 stp instance 3 root primary                                                    
 stp enable                                                                     
#                                                                                
interface GigabitEthernet0/0/1                 
 port link-type trunk
 port trunk allow-pass vlan 101 to 200                                          
 stp binding process 2 link-share                                               
#                                                                               
interface GigabitEthernet0/0/2                        
 port link-type trunk
 port trunk allow-pass vlan 101 to 200                                          
 stp binding process 2                                                          
 stp root-protection                                                            
#                                                                               
interface GigabitEthernet0/0/3          
 port link-type trunk
 port trunk allow-pass vlan 201 to 300                                            
 stp binding process 3                                                          
#                                                                               
interface GigabitEthernet0/0/4               
 port link-type trunk
 port trunk allow-pass vlan 201 to 300                                            
 stp binding process 3                                                          
#                                                                                
return