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    Configuring VLAN Spanning-Tree Protocol

    You can configure the VLAN Spanning-Tree Protocol (VSTP) under the following hierarchy level:

    To configure the VLAN Spanning-Tree Protocol:

    1. Enable VSTP as the version of spanning-tree protocol to be configured:
      [edit]
      user@host@ edit ... protocols vstp
    2. (Optional) For compatibility with older bridges that do not support VSTP, you can run force VSTP to run as the original IEEE 802.1D Spanning-Tree Protocol (STP) version:

      [edit ... protocols vstp]
      user@host# set force-version stp

      Note: If VSTP has been forced to run as the original STP version, you can revert back to VSTP by first removing the force-version statement from the configuration and then entering the clear spanning-tree protocol-migration configuration mode command.

    3. Configure the interfaces that participate in the VSTP instance.

      1. Enable configuration of the interface:
        [edit ... protocols vstp]
        user@host# edit interface interface-name
      2. Configure the interface priority:
        [edit ... protocols vstp interface interface-name]
        user@host# set priority interface-priority
      3. (Optional) Configure the interface as an edge port:
        [edit ... protocols vstp interface interface-name]
        user@host# set edge
    4. Enable configuration of a VLAN instance:
      [edit ... protocols vstp]
      user@host# edit vlan vlan-id
    5. Configure the bridge priority
      [edit ... protocols vstp vlan vlan-id]
      user@host# set bridge-priority bridge-priority

      For more information, see Understanding Bridge Priority for Election of Root Bridge and Designated Bridge.

    6. Configure hello BPDU timers.

      1. Configure the maximum expected arrival time of hello BPDUs:
        [edit ... protocols vstp vlan vlan-id]
        user@host# set max-age seconds
      2. Configure the time interval at which the root bridge transmits configuration BPDUs:
        [edit ... protocols vstp vlan vlan-id]
        user@host# set hello-time seconds
    7. (Optional) By default, the bridge port remains in the listening and learning states for 15 seconds before transitioning to the forwarding state. You can specify a delay from 4 through 20 seconds instead:
      [edit ... protocols vstp vlan vlan-id]
      user@host# set forward-delay seconds
    8. Configure the interfaces that participate in the VSTP instance.

      1. Enable configuration of the interface:
        [edit ... protocols vstp vlan vlan-id]
        user@host# edit interface interface-name
      2. Configure the interface priority:
        [edit ... protocols vstp vlan vlan-id interface interface-name]
        user@host# set priority interface-priority
      3. (Optional) Configure the interface as an edge port:
        [edit ... protocols vstp vlan vlan-id interface interface-name]
        user@host# set edge
    9. Verify the VSTP configuration:

      [edit]
      force-version stp; # Optional.
      interface interface-name {
      priority interface-priority;
      cost interface-link-cost; # Optional.
      mode (p2p | shared);
      edge; # Optional.
      }
      vlan vlan-id {
      bridge-priority bridge-priority;
      max-age seconds;
      hello-time seconds;
      forward-delay seconds; # Optional.
      interface interface-name {
      priority interface-priority;
      cost interface-link-cost; # Optional.
      mode (p2p | shared);
      edge; # Optional.
      }
      }
      }
      }
      }

    Modified: 2018-03-08