Checking Whether the MST Region Configuration Is Consistent on Two Devices in MSTP Mode

Procedure

  1. Configure the Huawei device to work in MSTP mode and the Cisco device in MST mode.
  2. Ensure that devices in the same MST region must use the same configurations including the MST region name, revision level, and mapping between VLANs and instances.

    Run the display stp region-configuration command on the Huawei device to check the effective MST region configuration.

    <HUAWEI>system-view
    [HUAWEI]display stp region-configuration                                        
     Oper configuration                                                             
       Format selector      :0                                                        
       Region name        :region1                                  
       Revision level     :1                                                                          
       Instance   VLANs Mapped           //Mapping between VLANs and instances                              
          0       1 to 9, 11 to 19, 21 to 29, 31 to 39, 41 to 49, 51 to 4094        
          1       10, 20, 30                                                        
          2       40, 50 

    Run the do show spanning-tree mst configuration command on the Cisco device to check the effective MST region configuration.

    Switch>enable
    Switch#configure terminal 
    Switch(config)#do show spanning-tree mst configuration                          
    Name      [region1]                       //                                      
    Revision  1     Instances configured 3    //                                      
                                                                                    
    Instance  Vlans mapped                    //Mapping between VLANs and instances                                      
    --------  --------------------------------------------------------------------- 
    0         1-9,11-19,21-29,31-39,41-49,51-4094                                   
    1         10,20,30                                                              
    2         40,50                                                                 
    -------------------------------------------------------------------------------

    If two devices use different MST region configuration, run the following commands to modify the MST region configuration on the Huawei or Cisco device.

    Configuration on the Huawei device:
    <HUAWEI>system-view
    [HUAWEI]stp region-configuration
    [HUAWEI-mst-region]region-name region1           //Configure the MST region name.
    [HUAWEI-mst-region]revision-level 1              //Configure the MSTP revision level. Two ends must use the same revision level.
    [HUAWEI-mst-region]instance 1 vlan 10 20 30      //Configure the mapping between VLANs and instances.
    [HUAWEI-mst-region]instance 2 vlan 40 50           
    [HUAWEI-mst-region]active region-configuration   //Activate the MST region configuration so that the MST region configuration takes effect.
    [HUAWEI-mst-region]return
    Configuration on the Cisco device:
    Switch>enable
    Switch#configure terminal
    Switch(config)#spanning-tree mst configuration
    Switch(config-mst)#name region1                //Configure the MST region name.
    Switch(config-mst)#revision 1                  //Configure the MSTP revision level. Two ends must use the same revision level.
    Switch(config-mst)#instance 1 vlan 10,20,30    //Configure the mapping between VLANs and instances.
    Switch(config-mst)#instance 2 vlan 40,50
    Switch(config-mst)#exit

  3. Check whether the digest of the MST region is the same.

    Run the display stp region-configuration digest command on the Huawei device to check the digest of the effective MST region.

    <HUAWEI>system-view
    [HUAWEI]display stp region-configuration digest                                 
     Oper configuration                                                             
       Format selector    :0                                                        
       Region name        :region1                                                  
       Revision level     :1                                                        
       Digest           :0x43A9ECEFACA62624BF0D53DB74D07750    //Digest of the MST region

    Run the show spanning-tree mst configuration digest command on the Cisco device to check the digest of the effective MST region.

    Switch>enable
    Switch#show spanning-tree mst configuration digest                              
    Name      [region1]                                                             
    Revision  1     Instances configured 3                                          
    Digest        0x43A9ECEFACA62624BF0D53DB74D07750    //Digest of the MST region
    Pre-std Digest  0x3A3769419E74DFA9970624BB26C57055

    If the values of Digest are different, run the stp config-digest-snoop command on the interface of the Huawei device connected to the Cisco device.

    [HUAWEI]interface GigabitEthernet 0/0/1
    [HUAWEI-GigabitEthernet0/0/1]stp config-digest-snoop

  4. Check whether two devices use the same path cost calculation algorithm.

    The following describes the path cost calculation algorithm on the Cisco device and Huawei device.
    Table 1 Path cost algorithm

    Cisco Switch

    Huawei Switch

    Path cost algorithm

    Default Configuration or Not

    Command Line

    Path cost algorithm

    Default Configuration or Not

    Command Line

    long

    No

    (config)#spanning-tree pathcost method long

    IEEE 802.1T

    Yes

    [HUAWEI]stp pathcost-standard dot1t

    short

    Yes (c3750/me3400)

    (config)#spanning-tree pathcost method short

    IEEE 802.1D-1998

    No

    [HUAWEI]stp pathcost-standard dot1d-1998

    Run the display stp interface interface-type interface-number command on the Huawei device to check the path cost algorithm.

    <HUAWEI>display stp interface GigabitEthernet 0/0/1                       
    -------[CIST Global Info][Mode RSTP]-------                                     
    ...                                            
    ----[Port6(GigabitEthernet0/0/1)][DOWN]----                                     
     Port Protocol       :Enabled                                                   
     Port Role           :Disabled Port                                             
     Port Priority       :128                                                       
     Port Cost(Dot1T ) :Config=auto / Active=200000000  //IEEE 802.1T

    Run the show spanning-tree detail command on the Cisco device to check the path cost algorithm. The default path cost algorithm used by different Cisco models is different. For example, the C7600 uses the long algorithm and the C3750 uses the short algorithm by default.

    Switch>enable
    Switch#show spanning-tree detail                                         
     VLAN0001 is executing the ieee compatible Spanning Tree protocol               
     ...                                                                                
     Port 8 (FastEthernet1/0/6) of VLAN0001 is designated listening                 
     Port path cost 19, Port priority 128, Port Identifier 128.8.        //short         
       Designated root has priority 32769, address a8b1.d45a.1080

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