display stp (MSTP process region view)

Function

The display stp command displays the status of and statistics about the Multiple Spanning Tree Protocol (MSTP).

Format

display stp [ instance instance-id ] [ interface { interface-name | interface-type interface-number } | vsi vsi-name pw pw-name ] tc-bpdu statistics

display stp [ instance instance-id ] topology-change

display stp active

display stp bridge { local | root }

display stp global

display stp [ instance instance-id ] abnormal-interface

display stp [ instance instance-id ] [ interface { interface-name | interface-type interface-number } | slot slot-id | vsi vsi-name pw pw-name ] [ brief ]

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.
interface-name	Specifies the interface name.	-
interface-type	Specifies the interface type.	-
interface-number	Specifies the interface number.	-
vsi vsi-name	Specifies the names of a virtual switching instance (VSI).	The vsi-name is a string of 1 to 31 case-sensitive characters, spaces not supported. When quotation marks are used around the string, spaces are allowed in the string.
pw pw-name	Specifies the names of a pseudo wire (PW).	The pw-name is a string of 1 to 15 case-sensitive characters, spaces not supported. When quotation marks are used around the string, spaces are allowed in the string.
tc-bpdu	Displays the statistics about sent and received topology change (TC) and topology change notification (TCN) BPDUs on interfaces.	-
statistics	Displays the statistics about sent and received topology change (TC) and topology change notification (TCN) BPDUs on interfaces.	-
topology-change	Displays statistics about Multiple Spanning Tree Protocol (MSTP) topology changes.	-
active	Displays the status of and statistics on spanning trees of all Up interfaces. To view information about spanning trees on all Up interfaces, run the display stp active command.	-
bridge	Displays detailed information about the spanning tree of a bridge. To view detailed information about the spanning trees of the root and local bridges, run the display stp bridge command.	-
local	Displays detailed information about the spanning tree of the local bridge.	-
root	Displays detailed information about the spanning tree of the root bridge.	-
global	Displays global Spanning Tree Protocol (STP) information.	-
abnormal-interface	Displays information about abnormal interfaces running the Spanning Tree Protocol (STP). Run the display stp abnormal-interface command can query information about abnormal STP interfaces quickly.	-
slot slot-id	Specifies the number of the slot where the interface resides.	The value is a string of 1 to 23 case-sensitive characters, spaces not supported.
brief	Displays the brief status.	-

Views

MSTP process region view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mstp	write

Usage Guidelines

Usage Scenario

The display stp command is used to check whether the spanning tree protocol is run on the existing device or specified interface.
If the Protocol Status field value is disabled, the spanning tree protocol is not run.
If STP/RSTP/MSTP has been run, information such as the working mode of the spanning tree protocol will be displayed.
The display stp brief command displays information about spanning trees on interfaces, but not global information.
The display stp global command displays global STP information.
The display stp tc-bpdu statistics command displays statistics about sent and received topology change and topology change notification BPDUs on interfaces.
To determine whether a fault has occurred on interfaces that send and receive TC (Topology Change)/TCN (Topology Change Notification) BPDUs, run display stp tc-bpdu statistics command to view statistics about sent and received BPDUs. The command output helps you locate the fault.
The display stp topology-change command displays statistics about Multiple Spanning Tree Protocol (MSTP) topology changes.
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.
The display stp active command displays the status of and statistics on spanning trees of all Up interfaces.
The display stp bridge command displays detailed information about the spanning trees of the root and local bridges.
The display stp abnormal-interface command displays information about abnormal interfaces running the STP.

Example

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

# Display information about spanning trees on all Up interfaces.

<HUAWEI> system-view
[~HUAWEI] stp process 1
[~HUAWEI-mst-process-1] stp region-configuration
[~HUAWEI-mst-process-1-region] display stp active
 Protocol Status       :Disabled 
 Protocol Standard     :IEEE 802.1s
 Version               :3
 CIST Bridge Priority  :32768
 MAC address           :38ba-99a7-5001
 Max age(s)            :20
 Forward delay(s)      :15
 Hello time(s)         :2
 Max hops              :20

# Display brief STP information.

<HUAWEI> system-view
[~HUAWEI] stp process 1
[~HUAWEI-mst-process-1] stp region-configuration
[~HUAWEI-mst-process-1-region] display stp global
Protocol Status            :Disabled
Bpdu-filter default        :Disabled
Tc-protection              :Enabled
Tc-protection threshold    :1
Tc-protection interval     :2s
Edged port default         :Disabled
Pathcost-standard          :Dot1T
Timer-factor               :3
Transmit-limit             :6
Bridge-diameter            :7
-------[CIST Global Info][Mode MSTP]-------
CIST Bridge         :32768.38ba-99a7-5001
Config Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
Active Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC      :32768.38ba-99a7-5001 / 0 (This bridge is the root)
CIST RegRoot/IRPC   :32768.38ba-99a7-5001 / 0 (This bridge is the root)
CIST RootPortId     :0.0
BPDU-Protection     :Disabled
TC or TCN received  :0
TC count per hello  :0
STP Converge Mode   :Normal
Time since last TC  :0 days 0h:0m:0s
Number of TC        :0
Topo Change Flag    :0

**Table 1** Description of the **display stp (MSTP process region view)** command output
Item	Description
Protocol Status	STP status: Enabled: STP is enabled. Disabled: STP is disabled.
Protocol Standard	Standards of the protocol.
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.
Version	Protocol version: 0: STP. 2: RSTP. 3: MSTP.
CIST Bridge	Common and internal spanning tree (CIST) bridge ID. The 16 left-most bits represent the bridge's priority in the CIST. The 48 right-most bits represent the bridge's MAC address.
CIST Root/ERPC	CIST root bridge ID/Cost of the external path (path from the switch to the CIST root bridge).
CIST RegRoot/IRPC	ID of the CIST region root bridge/Cost of the internal path (path from the switch to the CIST region root bridge).
CIST RootPortId	ID of the CIST root port. 0.0 indicates that the switch is the root bridge and does not provide any root port.
CIST Bridge Priority	Priority of the switch in CIST.
CIST Global Info	CIST global information.
MAC address	MAC address of the switch.
Max Age	Maximum lifetime of a BPDU.
Max hops	Maximum hops in Multiple Spanning Tree (MST) region.
Max age(s)	Maximum lifecycle of the BPDU.
Forward Delay	Time interface status transition takes.
Forward delay(s)	Time interface status transition takes.
Hello Time	Interval at which Bridge Protocol Data Units (BPDUs) are sent from the root bridge.
Hello time(s)	Interval at which BPDUs are sent from the root bridge.
Bpdu-filter default	Whether the function of configuring a port as a BPDU filter port is enabled: Enabled: The function of configuring a port as a BPDU filter port is enabled. Disabled: The function of configuring a port as a BPDU filter port is disabled.
Tc-protection	TC protection status: Enabled: TC protection is enabled. Disabled: TC protection function is disabled.
Tc-protection threshold	Threshold for MSTP to process TC BPDUs and immediately refresh forwarding entries per unit time.
Tc-protection interval	Time taken by MSTP to process the maximum number of TC BPDUs and immediately refresh forwarding entries.
Edged port default	Whether the function of configuring all ports of the device as edge ports is enabled: Enabled. Disabled.
Pathcost-standard	Method of calculating the MSTP path cost.
Timer-factor	Multiplier of Hello time.
Transmit-limit	Maximum number of BPDUs that the current interface can send per Hello time. For details, see stp transmit-limit.
Bridge-diameter	Network diameter of the MSTP.
Config Times	Manually configured BPDU parameters: Hello: interval at which BPDUs are sent. MaxAge: maximum lifetime of a BPDU. FwDly: time interface status transition takes. MaxHop: maximum number of hops in the MST region.
Active Times	BPDUs parameters that are being used: Hello: interval at which BPDUs are sent. MaxAge: maximum lifetime of a BPDU. FwDly: time interface status transition takes. MaxHop: maximum number of hops in the MST region.
BPDU-Protection	Whether BPDU protection is enabled: Disabled. Enabled.
TC or TCN received	Number of received TC or TCN BPDUs.
TC count per hello	Number of TC BPDUs received each Hello time.
TC or TCN send	Number of TC or TCN BPDUs sent by the port.
TC received	Number of received TC BPUDs.
STP Converge Mode	STP convergence mode, which can be fast or normal.
Mode	STP mode: STP. RSTP. MSTP.
Time since last Topology Change	Time since the last topology change.
Time since last TC	Time past since the last topology changed.
Number of Topology Changes	Total number of topology changes since MSTP initialization.
Number of suppressed topologychange traps	Total number of suppressed topology-change traps.
Number of TC	Number of topology changes.
Interface	Interface type.
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.
Topology Change initiator(detected)	Interface that triggers a topology change because the interface status changes to DETECTED after the interface status changes from blocked to unblocked.
Last TC occurred	Interface that causes the last topology change. This parameter is not displayed when Number of TC is 0.
Root ID	MSTP root bridge ID.
Root Cost	MSTP root path cost.
Root Port	Root port.
Port Protocol	The status of the port protocol: enable: STP is enabled on the port. disable: STP is disabled on the port.
Port Role	In a CIST area, the four port roles are as follows: CIST Root Port. CIST Designated Port. CIST Alternate Port. CIST Backup Port.
Port Priority	Priority of the port. For the detailed configuration, see stp port priority.
Designated Bridge/Port	ID of the designated switch and port. The 16 left-most bits of the switch ID represent the priority of the switch in the CIST region; the 48 right-most bits represent the MAC address of the switch. The left-most 4 bits of the port ID represent the priority and the right-most 12 bits represent the port number.
Port Edged	Status of an edge port that is specified by the administrator. enabled. disabled. Config indicates that the value is configured by using the. stp edged-port command. Active indicates the actual value.
Point-to-point	Link type of the port. Config indicates that the link type is configured using the stp point-to-point command. Active indicates the actual link type.
Transit Limit	Maximum number of the BPDUs sent by the current port before each Hello time expires. For the detailed configuration, see stp transmit-limit.
Protection Type	Protection type , which can be: None: no protection. LoopBack: self-loop detection. BpduRoot: BPDU and root protection. ROOT: root protection. BPDU: BPDU protection. Loop: loop protection. BpduLoop: BPDU and loop protection.
Port STP Mode	STP mode on an interface.
Config-digest-snoop	Configuration digest snooping function: Displayed only after the. stp config-digest-snoop command is configured to enable the configuration digest snooping function on the port. If the port does not have the function enabled, this field is not displayed. snooped=false: The configuration digest of the packets on the remote end is the same as that on the local end. snooped=true: The configuration digest of the packets on the remote end is different from that on the local end.
Port Protocol Type	Format of the packets that the interface receives and sends: auto. legacy. dot1s. The default value is. auto. Config indicates that the packet format is configured using the. stp compliance command. Active indicates the actual packet format.
BPDU Encapsulation	Format of the BPDUs received and sent through a port.
PortTimes	Values in the BPDUs on the interface: Hello: interval at which BPDUs are sent. MaxAge: maximum lifecycle of the BPDU. FwDly: forwarding delay timer. MaxHop: maximum hops in the MST region.
BPDU Sent	Statistics about sent BPDUs: TCN: topology change notification. Config: STP BPDUs. RST: RSTP BPDUs. MST: MSTP BPDUs.
BPDU Received	Statistics about received BPDUs.
Port Cost(Legacy)	Path cost of the port. It is calculated by dot1t algorithm. config: path cost manually configured. active: actual path cost.
MSTI Bridge ID	Multiple Spanning Tree instance (MSTI) bridge ID.
MSTI RootPortId	ID of the MSTI root port. 0.0 indicates that the switch is the root bridge and does not provide any root port.
Cost to Master	Cost of the path from the switch to the bridge where the master interface resides. 0 indicates that the master interface resides on the current bridge.
Last forwarding time	Time when the interface last entered the forwarding state.
MSTI RegRoot/IRPC	MSTI root bridge ID/Cost of the internal path (path from the switch to the MSTI root bridge).
Master Bridge	ID of the bridge where the master interface resides. The 16 left-most bits represent the bridge's priority in the CIST. The 48 right-most bits represent the bridge's MAC address.
Port Cost(Dot1T )	Path cost (calculated by dot1t) of an interface: Config: configured path costActive: path cost that is being used. Active: path cost that is being used.