STP/RSTP/MSTP: display stp [ process process-id ] [ instance instance-id ] topology-change
VBST: display stp [ vlan vlan-id ] topology-change
| Parameter | Description | Value |
|---|---|---|
| process process-id | Displays statistics about the topology changes of a specified MSTP process. If this parameter is not specified, the statistics about the topology changes of MSTP process 0 are displayed. |
The value is an integer ranging from 1 to 31. |
| instance instance-id | Displays statistics about the topology changes of a specified STP instance. If this parameter is not specified, the statistics about the topology changes of a CIST instance are displayed. |
The value is an integer ranging from 0 to 4094.
Value 0 refers to CIST.
NOTE:
instance-id ranges from 0 to 4094. Each process supports a maximum of 65 instances. |
| vlan vlan-id | Displays statistics on topology changes in a specified VLAN. If vlan vlan-id is not specified, statistics on topology changes in all VLANs are displayed. NOTE:
If vlan vlan-id is specified, only statistics on topology changes of VBST are displayed. |
The value is an integer that ranges from 1 to 4094. |
Usage Scenario
On a Layer 2 network running MSTP, a device clears ARP entries and MAC entries after receiving topology change packets. If a device receives too many topology change packets, the device will frequently clear ARP entries and MAC entries, causing high CPU usage. As a result, network traffic is instable.
The display stp topology-change command can be used to display the statistics about MSTP/VBST topology changes. If the statistics increase, network flapping occurs.
Prerequisites
In the case of a non-zero process, the stp process process-id command must be used to create a process.
# Display statistics about MSTP topology changes when MSTP is running.
<HUAWEI> 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) :GigabitEthernet0/0/1 Topology change last received from :00e0-5b3c-c100 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) :GigabitEthernet0/0/2 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) :GigabitEthernet0/0/3 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
<HUAWEI> display stp vlan 5 topology-change
VLAN 5 topology change information
Number of topology changes :316
Topology change initiator(notified) :GigabitEthernet0/0/5
Time since last topology change :0 days 0h:3m:18s
Topology change last received from :5489-9876-a2b0
Item |
Description |
|---|---|
Number of topology changes |
Total number of topology changes since initialization. NOTE:
The number of received and sent TC BPDUs in each VLAN may be different during topology convergence, so the number of topology changes in each VLAN may be different. |
Time since last topology change |
Time since the last topology change. |
Topology change initiator(detected) |
Interface that initiates a topology change because the interface status changes to detected. |
Topology change initiator(notified) |
Interface that initiates a topology change after receiving a topology change packet. |
Topology change last received from |
Source bridge MAC address contained in a topology change packet. |
Number of generated topologychange traps |
Total number of generated topology-change traps. |
Number of suppressed topologychange traps |
Total number of suppressed topology-change traps. |