Configuring MSTP (NSM Procedure)

Multiple Spanning Tree Protocol (MSTP) is used to create a loop-free topology in networks using multiple spanning tree regions, each region containing multiple spanning-tree instances (MSTIs). MSTIs provide different paths for different VLANs. This functionality facilitates better load sharing across redundant links.

MSTP supports up to 64 regions, each one capable of supporting 4094 MSTIs.

To configure MSTP:

  1. In the navigation tree, select Device Manager > Devices. In Device Manager, select the device for which you want to configure a port mirror analyzer.
  2. In the Configuration tree, expand Protocols > MSTP.
  3. Add/modify MSTP settings as specified in Table 89.

Note: After you make changes to a device configuration, you must push that updated device configuration to the physical security device for those changes to take effect. You can update multiple devices at one time. See Updating Devices for more information.

Table 89: MSTP Configuration Fields



Your Action


Specifies whether MSTP must be disabled on the port.

Click to select the option.

Configuration Name

Specifies the configuration name.

Type a name.

Revision Level

Specifies the configuration revision level.

Select a value.

Max Hops

Specifies the number of hops in a region before the BPDU is discarded.

Select a value.

Max Age

Specifies the maximum-aging time for all MST instances. The maximum aging time is the number of seconds a switch waits without receiving spanning-tree configuration messages before attempting a reconfiguration.

Select a value.

Hello time

Specifies the hello time for all MST instances.

Select a value.

Forward Delay

Specifies the number of seconds a port waits before changing from its spanning-tree learning and listening states to the forwarding state.

Select a value.

Bridge Priority

Specifies the bridge priority.

Enter a value.

Bpdu Block on Edge

Specifies whether Bpdu blocks must be processed.

Select to enable the feature.


Specifies MSTP settings for the interface.

  1. Click the expand icon.
  2. Specify the interface name.
  3. Specify the port priority.
  4. Specify the path cost. MSTP uses the path cost when selecting an interface to place into the forwarding state. A lower path cost represents higher-speed transmission.
  5. Specify the mode. The link type can be shared or point-to-point.
  6. Select Edge to enable the feature.
  7. Select No root port if it is not specified.
  8. Click OK.
  9. Specify the Bpdu timeout action:
    • Block
    • Alarm


Specifies MST instances settings for an interface or VLAN.

  1. Specify the Msti ID.
  2. Enter a comment.
  3. Specify the bridge priority.
  4. Click OK.