Defining MSTP Interface Settings

The MSTP Interface Settings page enables you to configure the port MSTP settings for every MST instance, and to view information that has currently been learned by the protocol, such as the designated bridge per MST instance.

To configure the ports in an MST instance:

  1. Click Spanning Tree > MSTP Interface Settings. The MSTP Interface Settings page displays.
  2. Enter the parameters.
    • Instance equals To--Select the MSTP instance to be configured.
    • Interface Type equals to--Select whether to display the list of ports or LAGs.

    The MSTP parameters for the interfaces on the instance are displayed.

  3. Select an interface, and click Edit. The Edit Interface Settings page displays.
  4. Enter the parameters.
    • Instance ID--Select the MST instance to be configured.
    • Interface--Select the interface for which the MSTI settings are to be defined.
    • Interface Priority--Set the port priority for the specified interface. and MST instance.
    • Path Cost--Set the port contribution to the root path cost or use the default value. The root path cost is the cost of the switch to the Root Bridge of the specified MST instance.
    • Port State--Displays the MSTP status of the specific port on a specific MST instance. The parameters are defined as:
      • Disabled--STP is currently disabled.
      • Blocking--The port on this instance is currently blocked, and cannot forward traffic (with the exception of BPDU data) or learn MAC addresses.
      • Listening--The port on this instance is in Listening mode. The port cannot forward traffic, and cannot learn MAC addresses.
      • Learning--The port on this instance is in Learning mode. The port cannot forward traffic, but it can learn new MAC addresses.
      • Forwarding--The port on this instance is in Forwarding mode. The port can forward traffic and learn new MAC addresses.
    • Port Role--Displays the port or LAG role, per port or LAG per instance, assigned by the MSTP algorithm to provide STP paths:
      • Root--Forwarding packets through this interface provides the lowest cost path to forward packets to the root device.
      • Designated--The interface through which the bridge is connected to the LAN, that provides the lowest root path cost from the LAN to the Root Bridge for the MST instance.
      • Alternate--The interface provides an alternate path to the root device from the root interface.
      • Backup--The interface provides a backup path to the designated port path toward the Spanning Tree leaves. Backup ports occur when two ports are connected in a loop by a point-to-point link. Backup ports also occur when a LAN has two or more connections connected to a shared segment.
      • Disabled--The interface does not participate in the Spanning Tree.
    • Mode--Displays the current Spanning Tree mode.
      • Classic STP--Classic STP is enabled on the port.
      • Rapid STP--Rapid STP is enabled on the port.
      • MSTP--MSTP is enabled on the port.
    • Type--Displays the MST type of the port.
      • Boundary--A Boundary port attaches MST bridges to a LAN in an outlying region. If the port is a boundary port, it also indicates whether the device on the other side of the link is working in RSTP or STP mode.
      • Internal--The port is an internal port.
    • Designated Bridge ID--Displays the bridge ID number that connects the link or shared LAN to the root.
    • Designated Port ID--Displays the Port ID number on the designated bridge that connects the link or the shared LAN to the root.
    • Designated Cost--Displays the cost of the port participating in the STP topology. Ports with a lower cost are less likely to be blocked if STP detects loops.
    • Remaining Hops--Displays the hops remaining to the next destination.
    • Forward Transitions--Displays the number of times the port has changed from the Forwarding state to the Blocking state.
  5. Click Apply. The Running Configuration file is updated..