display stp topology-change

Function

The display stp topology-change command displays statistics about Multiple Spanning Tree Protocol (MSTP) topology changes.

Format

display stp [ instance instance-id ] topology-change

Parameters

Parameter	Description	Value
instance instance-id	Displays statistics about the topology changes of a specified STP instance. If instance instance-id is not specified, statistics about the topology changes of a Common and Internal Spanning Tree (CIST) instance are displayed.	The value is an integer ranging from 0 to 4094, Value 0 indicates CIST.

Parameter

Description

Value

instance instance-id

Displays statistics about the topology changes of a specified STP instance.

If instance instance-id is not specified, statistics about the topology changes of a Common and Internal Spanning Tree (CIST) instance are displayed.

The value is an integer ranging from 0 to 4094, Value 0 indicates CIST.

Views

MSTP process view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mstp	write

Usage Guidelines

Usage Scenario

On a Layer 2 network running MSTP, a device clears ARP entries and MAC entries after receiving TC BPDUs. If a device receives too many TC BPDUs, the device will frequently clear ARP entries and MAC entries, causing high CPU usage. As a result, network traffic is unstable.

You can run the display stp topology-change command to display statistics about MSTP topology changes. If the statistics increase, network flapping occurs.

Example

The actual command output varies according to the device. The command output here is only an example.

# Display statistics about MSTP topology changes.

<HUAWEI> system-view
[~HUAWEI] stp process 1
[*HUAWEI-mst-process-1] display stp topology-change
CIST topology change information
   Number of topology changes             :5
   Time since last topology change        :0 days 0h:23m:19s
   Topology change initiator(detected)    :GigabitEthernet0/1/1
   Topology Change last received from     :00e0-fc12-3456
   Number of generated topologychange traps :   5
   Number of suppressed topologychange traps:   3
 MSTI 1 topology change information
   Number of topology changes             :5
   Time since last topology change        :0 days 0h:23m:19s
   Topology change initiator(detected)    :GigabitEthernet0/1/2
   Number of generated topologychange traps :   5
   Number of suppressed topologychange traps:   3
 MSTI 2 topology change information
   Number of topology changes             :5
   Time since last topology change        :0 days 0h:23m:19s
   Topology change initiator(notified)    :GigabitEthernet0/1/3
   Number of generated topologychange traps :   5
   Number of suppressed topologychange traps:   3
 MSTI 3 topology change information
   Number of topology changes             :5
   Time since last topology change        :0 days 0h:23m:19s

**Table 1** Description of the **display stp topology-change** command output
Item	Description
Number of Topology Changes	Total number of topology changes since MSTP initialization.
Number of generated topologychange traps	Total number of generated TC traps.
Time since last Topology Change	Time past since the last topology changed.
Topology Change initiator(detected)	Interface that triggers a topology change because the interface status changes to Detected.
Topology Change initiator(notified)	Interface that triggers a topology change after receiving a TC BPDU.
Topology Change last received from	Source bridge MAC address contained in a TC BPDU.
number of suppressed topologychange traps	number of suppressed topologychange traps.