Example for Configuring Basic STP Functions

Procedure

1. Configure basic STP functions.

   1. Configure the STP mode for the switches on the ring network.

      # Configure the STP mode on SwitchA.

      <HUAWEI> system-view
      [HUAWEI] sysname SwitchA
      [SwitchA] stp mode stp

      # Configure the STP mode on SwitchB.

      <HUAWEI> system-view
      [HUAWEI] sysname SwitchB
      [SwitchB] stp mode stp

      # Configure the STP mode on SwitchC.

      <HUAWEI> system-view
      [HUAWEI] sysname SwitchC
      [SwitchC] stp mode stp

      # Configure the STP mode on SwitchD.

      <HUAWEI> system-view
      [HUAWEI] sysname SwitchD
      [SwitchD] stp mode stp

   2. Configure the primary and secondary root bridges.

      # Configure SwitchA as the primary root bridge.

      [SwitchA] stp root primary

      # Configure SwitchD as the secondary root bridge.

      [SwitchD] stp root secondary

   3. Set a path cost for the ports to be blocked.

      • The path cost value range depends on path cost calculation methods. This example uses the Huawei proprietary calculation method and sets the path cost to 20000 (the greatest value in the range).

      • All switching devices on a network must use the same path cost calculation method.

      # On Switch A, set the path cost calculation method to the Huawei proprietary method.

      [SwitchA] stp pathcost-standard legacy

      # On Switch B, set the path cost calculation method to the Huawei proprietary method.

      [SwitchB] stp pathcost-standard legacy

      # On Switch C, set the path cost of GigabitEthernet1/0/1 to 20000.

      [SwitchC] stp pathcost-standard legacy
      [SwitchC] interface gigabitethernet 1/0/1
      [SwitchC-GigabitEthernet1/0/1] stp cost 20000
      [SwitchC-GigabitEthernet1/0/1] quit

      # On SwitchD, set the path cost calculation method to the Huawei proprietary method.

      [SwitchD] stp pathcost-standard legacy

   4. Enable STP to eliminate loops.

      • Configure the ports connected to PCs as both edge ports.

        # Configure GigabitEthernet1/0/2 of SwitchB as both an edge port.

        [SwitchB] interface gigabitethernet 1/0/2
        [SwitchB-GigabitEthernet1/0/2] stp edged-port enable
        [SwitchB-GigabitEthernet1/0/2] quit

        (Optional) Configure BPDU protection on SwitchB.

        [SwitchB] stp bpdu-protection

        # Configure GigabitEthernet1/0/2 of SwitchC as both an edge port.

        [SwitchC] interface gigabitethernet 1/0/2
        [SwitchC-GigabitEthernet1/0/2] stp edged-port enable
        [SwitchC-GigabitEthernet1/0/2] quit

        (Optional) Configure BPDU protection on SwitchC.

        [SwitchC] stp bpdu-protection

        If edge ports are connected to network devices that have STP enabled and BPDU protection is enabled, the edge ports will be shut down and their attributes remain unchanged after they receive BPDUs.

      • Enable STP globally.

        # Enable STP globally on SwitchA.

        [SwitchA] stp enable

        # Enable STP globally on SwitchB.

        [SwitchB] stp enable

        # Enable STP globally on SwitchC.

        [SwitchC] stp enable

        # Enable STP globally on SwitchD.

        [SwitchD] stp enable

2. Verify the configuration.

   After the preceding configuration is complete and the network becomes stable, perform the following operations to verify the configuration:

   # Run the display stp brief command on SwitchA to view the port states and protection type. The following information is displayed:

   [SwitchA] display stp brief
    MSTID  Port                        Role  STP State     Protection
      0    GigabitEthernet1/0/1        DESI  FORWARDING      NONE
      0    GigabitEthernet1/0/2        DESI  FORWARDING      NONE

   After SwitchA is configured as the root bridge, GigabitEthernet 1/0/2 connected to SwitchB and GigabitEthernet 1/0/1connected to SwitchD are elected as designated ports through spanning tree calculation.

   # Run the display stp interface gigabitethernet 1/0/1 brief command on SwitchB to view status of GigabitEthernet 1/0/1. The following information is displayed:

   [SwitchB] display stp interface gigabitethernet 1/0/1 brief
    MSTID  Port                        Role  STP State     Protection
      0    GigabitEthernet1/0/1        DESI  FORWARDING      NONE      

   GigabitEthernet 1/0/1 is elected as a designated port and is in the Forwarding state.

   # Run the display stp brief command on SwitchC to view the interface states and protection type. The following information is displayed:

   [SwitchC] display stp brief
    MSTID  Port                        Role  STP State     Protection
      0    GigabitEthernet1/0/1        ALTE  DISCARDING      NONE     
      0    GigabitEthernet1/0/3        ROOT  FORWARDING      NONE      

   GigabitEthernet 1/0/3 is elected as a root port and is in the Forwarding state.

   GigabitEthernet 1/0/1 is elected as an alternate port and is in the Discarding state.