PVST configuration example

As shown in Figure 34, Device A and Device B work at the distribution layer, and Device C and Device D work at the access layer.

Configure PVST to meet the following requirements:

• Packets of a VLAN are forwarded along the spanning trees of the VLAN.

• VLAN 10, VLAN 20, and VLAN 30 are terminated on the distribution layer devices, and VLAN 40 is terminated on the access layer devices.

• The root bridge of VLAN 10 and VLAN 20 is Device A.

• The root bridge of VLAN 30 is Device B.

• The root bridge of VLAN 40 is Device C.

1. Configure VLANs and VLAN member ports. (Details not shown.)

   • Create VLAN 10, VLAN 20, and VLAN 30 on both Device A and Device B.

   • Create VLAN 10, VLAN 20, and VLAN 40 on Device C.

   • Create VLAN 20, VLAN 30, and VLAN 40 on Device D.

   • Configure the ports on these devices as trunk ports and assign them to related VLANs.

2. Configure Device A:

   # Set the spanning tree mode to PVST.

   <DeviceA> system-view
   [DeviceA] stp mode pvst
   

   # Configure the device as the root bridge of VLAN 10 and VLAN 20.

   [DeviceA] stp vlan 10 20 root primary
   

   # Enable the spanning tree feature globally and in VLAN 10, VLAN 20, and VLAN 30.

   [DeviceA] stp global enable
   [DeviceA] stp vlan 10 20 30 enable
   

3. Configure Device B:

   # Set the spanning tree mode to PVST.

   <DeviceB> system-view
   [DeviceB] stp mode pvst
   

   # Configure the device as the root bridge of VLAN 30.

   [DeviceB] stp vlan 30 root primary
   

   # Enable the spanning tree feature globally and in VLAN 10, VLAN 20, and VLAN 30.

   [DeviceB] stp global enable
   [DeviceB] stp vlan 10 20 30 enable
   

4. Configure Device C:

   # Set the spanning tree mode to PVST.

   <DeviceC> system-view
   [DeviceC] stp mode pvst
   

   # Configure the device as the root bridge of VLAN 40.

   [DeviceC] stp vlan 40 root primary
   

   # Enable the spanning tree feature globally and in VLAN 10, VLAN 20, and VLAN 40.

   [DeviceC] stp global enable
   [DeviceC] stp vlan 10 20 40 enable
   

5. Configure Device D:

   # Set the spanning tree mode to PVST.

   <DeviceD> system-view
   [DeviceD] stp mode pvst
   

   # Enable the spanning tree feature globally and in VLAN 20, VLAN 30, and VLAN 40.

   [DeviceD] stp global enable
   [DeviceD] stp vlan 20 30 40 enable
   

When the network is stable, use the display stp brief command to display brief spanning tree information on each device.

# Display brief spanning tree information on Device A.

[DeviceA] display stp brief
 VLAN ID     Port                                      Role  STP State     Protection
 10          Ten-GigabitEthernet1/0/1                  DESI  FORWARDING    NONE
 10          Ten-GigabitEthernet1/0/3                  DESI  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/1                  DESI  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/2                  DESI  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/3                  DESI  FORWARDING    NONE
 30          Ten-GigabitEthernet1/0/2                  DESI  FORWARDING    NONE
 30          Ten-GigabitEthernet1/0/3                  ROOT  FORWARDING    NONE

# Display brief spanning tree information on Device B.

[DeviceB] display stp brief
 VLAN ID     Port                                      Role  STP State     Protection
 10          Ten-GigabitEthernet1/0/2                  DESI  FORWARDING    NONE
 10          Ten-GigabitEthernet1/0/3                  ROOT  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/1                  DESI  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/2                  DESI  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/3                  ROOT  FORWARDING    NONE
 30          Ten-GigabitEthernet1/0/1                  DESI  FORWARDING    NONE
 30          Ten-GigabitEthernet1/0/3                  DESI  FORWARDING    NONE

# Display brief spanning tree information on Device C.

[DeviceC] display stp brief
 VLAN ID     Port                                      Role  STP State     Protection
 10          Ten-GigabitEthernet1/0/1                  ROOT  FORWARDING    NONE
 10          Ten-GigabitEthernet1/0/2                  ALTE  DISCARDING    NONE
 20          Ten-GigabitEthernet1/0/1                  ROOT  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/2                  ALTE  DISCARDING    NONE
 20          Ten-GigabitEthernet1/0/3                  DESI  FORWARDING    NONE
 40          Ten-GigabitEthernet1/0/3                  DESI  FORWARDING    NONE

# Display brief spanning tree information on Device D.

[DeviceD] display stp brief
 VLAN ID     Port                                      Role  STP State     Protection
 20          Ten-GigabitEthernet1/0/1                  ALTE  DISCARDING    NONE
 20          Ten-GigabitEthernet1/0/2                  ROOT  FORWARDING    NONE
 20          Ten-GigabitEthernet1/0/3                  ALTE  DISCARDING    NONE
 30          Ten-GigabitEthernet1/0/1                  ROOT  FORWARDING    NONE
 30          Ten-GigabitEthernet1/0/2                  ALTE  DISCARDING    NONE
 40          Ten-GigabitEthernet1/0/3                  ROOT  FORWARDING    NONE

Based on the output, you can draw a topology for each VLAN spanning tree, as shown in Figure 35.