display stp abnormal-interface

Function

The display stp abnormal-interface command displays information about abnormal interfaces running the Spanning Tree Protocol (STP) in a Multiple Spanning Tree Protocol (MSTP) process.

Format

display stp [ instance instance-id ] abnormal-interface

Parameters

Parameter	Description	Value
instance instance-id	Displays the status of and statistics about a specified spanning tree instance. If instance <instance-id> is not specified, the status of and statistics about all spanning tree instances will be displayed in the sequence of the interface numbers.	The value is an integer ranging from 0 to 4094, Value 0 indicates CIST.

Parameter

Description

Value

instance instance-id

Displays the status of and statistics about a specified spanning tree instance.

If instance <instance-id> is not specified, the status of and statistics about all spanning tree instances will be displayed in the sequence of the interface numbers.

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

If a device has many interfaces, querying information about abnormal STP interfaces by running the display stp command takes a long time.

To shorten the time, run the display stp abnormal-interface command.

Example

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

# Display information about abnormal STP interfaces of MSTP process 1.

<HUAWEI> system-view
[~HUAWEI] stp process 1
[*HUAWEI-mst-process-1] display stp instance 0 abnormal-interface
MSTID    Interface                     Status          Reason                   
   0     GigabitEthernet0/1/8          DISCARDING      LOOP-Protected           
   0     GigabitEthernet0/1/9          DOWN            BPDU-Protected           
   0     GigabitEthernet0/1/10          DISCARDING      ROOT-Protected           
   0     GigabitEthernet0/1/11          DISCARDING      LOOP-Detected

**Table 1** Description of the **display stp abnormal-interface** command output
Item	Description
MSTID	ID of an MSTP instance.
Interface	Interface type.
Status	Status of an interface after the STP protection takes effect: DOWN: The physical status of the interface is Down (including error-down). DISCARDING: The interface is blocked after the topology of the spanning tree becomes stable.
Reason	An STP interface becomes abnormal due to one of the following: Root-Protected: The root protection takes effect. Loop-Protected: The loop protection takes effect. BPDU-Protected: The bridge protocol data unit (BPDU) protection takes effect. Loop-Detected: The ring detection takes effect.