Configuring MST region-related parameters (especially the VLAN mapping table) is probable to result in network topology jitter. To reduce network topology jitter caused by the configuration, multiple spanning tree protocol (MSTP) does not recalculate spanning trees immediately after the configuration; it does this only after you activate the new MST region-related settings or enable MSTP, and then the new settings can really take effect.

When you carry out this command, MSTP will replace the currently running MST region–related parameters with the parameters you have just configured and will perform spanning tree recalculation.

Related commands: instance, region-name, revision-level, vlan-mapping modulo, and check region-configuration.

Examples

# Activate the MST region-related settings.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp region-configuration

[device-mst-region] active region-configuration

bpdu-drop any

Syntax

bpdu-drop any

undo bpdu-drop any

View

Ethernet port view

Parameters

None

Description

Use the bpdu-drop any command to enable BPDU dropping on the Ethernet port.

Use the undo bpdu-drop any command to disable BPDU dropping on the Ethernet port.

By default, BPDU dropping is disabled.

In a STP-enabled network, some users may send BPDU packets to the device continuously in order to destroy the network. When a device receives the BPDU packets, it will forward them to other devices. As a result, STP calculation is performed repeatedly, which may occupy too much CPU of the devices or cause errors in the protocol state of the BPDU packets.

In order to avoid this problem, you can enable BPDU dropping on Ethernet ports. Once the function is enabled on a port, the port will not receive or forward any BPDU packets. In this way, the device is protected against the BPDU packet attack so that the STP calculation is assured to be right.

Examples

# Enable BPDU dropping on GigabitEthernet 1/0/1.

<device>system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] bpdu-drop any

check region-configuration

Syntax

check region-configuration

View

MST region view

Parameters

None

Description

Use the check region-configuration command to display the MST region-related configuration which is being modified currently, including region name, revision level, and VLAN mapping table.

In MSTP, the configuration of MST regions must be right, especially the VLAN mapping table. MSTP-enabled devices are in the same region only when they have the same MST region-related configuration, including region name, revision level, and VLAN mapping table. A device cannot be in the expected region if any of the three MST region-related parameters mentioned above are not consistent with those of another device in the region.

This command is used to display the configuration information of inactivated MST regions. You can use this command to find the MST region the device currently belongs to or check to see whether or not the MST region-related configuration is correct.

Related commands: instance, region-name, revision-level, vlan-mapping modulo, and active region-configuration.

Examples

# Display the MST region-related configuration.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp region-configuration

[device-mst-region] check region-configuration

Admin Configuration

Format selector :0

Region name :00e0fc003600

Revision level :0

Instance Vlans Mapped

0 1 to 9, 11 to 4094

16 10

Table 1-1 check region-configuration command output description

Field	Description
Format selector	The selector specified by MSTP
Region name	The name of the MST region
Revision level	The revision level of the MST region
Instance Vlans Mapped	VLAN-to-MSTI mappings in the MST region

display stp

Syntax

display stp [ instance instance-id ] [ interface interface-list ] [ brief ]

View

Any view

Parameters

instance-id: ID of the spanning tree instance ranging from 0 to 16. The value of 0 refers to the common and internal spanning tree (CIST).

interface-list: Ethernet port list. You can specify multiple Ethernet ports by providing this argument in the form of interface-list = { interface-type interface-number [ to interface-type interface-number ] } &<1-10>, where &<1-10> means that you can provide up to 10 port indexes/port index ranges for this argument.

slot slot-number: Specifies a slot whose STP-related information is to be displayed.

brief: Displays only port state and protection measures taken on the port.

Description

Use the display stp command to display the state and statistical information about one or all spanning trees.

The state and statistical information about MSTP can be used to analyze and maintain the topology of a network. It can also be used to make MSTP operate properly.

l If neither spanning tree instance nor port list is specified, the command displays spanning tree information about all spanning tree instances on all ports in the order of port number.

l If only one spanning tree instance is specified, the command displays information about the specified spanning tree instance on all ports in the order of the port number.

l If only a port list is specified, the command displays information about all spanning tree instances on these ports in the order of the port numbers.

l If both a spanning tree instance ID list and a port list are specified, the command displays spanning tree information about the specified spanning tree instances and the specified ports in the order of spanning tree instance ID.

MSTP state information includes:

l Global CIST parameters: Protocol operating mode, device priority in the CIST instance, MAC address, hello time, max age, forward delay, max hops, the common root of the CIST, the external path cost for the device to reach the CIST common root, region root, the internal path cost for the device to reach the region root, CIST root port of the device, the state of the BPDU guard function (enabled or disabled), and the state of the digest snooping feature (enabled or disabled).

l CIST port parameters: Port protocol, port role, port priority, path cost, designated bridge, designated port, edge port/non-edge port, whether or not the link on a port is a point-to-point link, the maximum transmitting speed, type of the enabled root guard function, state of the digest snooping feature (enabled or disabled), VLAN mappings, hello time, max age, forward delay, Message-age time, and remaining hops.

l Global MSTI parameters: MSTI instance ID, bridge priority of the instance, region root, internal path cost, MSTI root port, and master bridge.

l MSTI port parameters: Port state, role, priority, path cost, designated bridge, designated port, and remaining hops.

The statistical information includes: the numbers of the TCN BPDUs, the configuration BPDUs, the RST BPDUs, and the MST BPDUs transmitted/received by each port.

Related commands: reset stp.

Examples

# Display the state and statistical information about a spanning tree.

<device> display stp instance 0 interface GigabitEthernet1/0/1 to GigabitEthernet1/0/4 brief

MSTID Port Role STP State Protection

0 GigabitEthernet1/0/1 ALTE DISCARDING LOOP

0 GigabitEthernet1/0/2 DESI FORWARDING NONE

0 GigabitEthernet1/0/3 DESI FORWARDING NONE

0 GigabitEthernet1/0/4 DESI FORWARDING NONE

Table 1-2 display stp command output description

Field	Description
MSTID	ID of a spanning tree instance in the MST region
Port	Port index corresponding to a spanning tree instance
Role	Port role
STP State	STP state on the port, which can be forwarding and discarding
Protection	Guard type of the port

display stp abnormalport

Syntax

display stp abnormalport

View

Any view

Parameters

None

Description

Use the display stp abnormalport command to display the ports that are blocked by STP guard functions.

Examples

# Display the ports that are blocked by STP guard functions.

<device> display stp abnormalport

MSTID Port Block Reason

--------- -------------------- -------------

0 GigabitEthernet1/0/20 Root-Protection

1 GigabitEthernet1/0/21 Loop-Protection

Table 1-3 display stp abnormalport command output description

Field	Description
MSTID	MST instance ID in the MST region
Port	Port number
Block Reason	The function blocking the port

display stp portdown

Syntax

display stp portdown

View

Any view

Parameters

None

Description

Use the display stp portdown command to display the ports that are shut down by STP guard functions.

Examples

# Display the ports that are shut down by STP guard functions.

<device> display stp portdown

Port Down Reason

--------------------- ------------

GigabitEthernet1/0/20 BPDU-Protection

Table 1-4 display stp portdown command output description

Field	Description
Port	Port number
Down Reason	The function shutting down the port

display stp region-configuration

Syntax

display stp region-configuration

View

Any view

Parameters

None

Description

Use the display stp region-configuration command to display the activated MST region configuration, including the region name, region revision level, and VLAN-to-STI mappings configured for the device.

Related commands: stp region-configuration.

Examples

# Display the configuration of the MST region.

<device> display stp region-configuration

Oper Configuration

Format selector :0

Region name :hello

Revision level :0

Instance Vlans Mapped

0 21 to 4094

1 1 to 10

2 11 to 20

Table 1-5 display stp region-configuration command output description

Field	Description
Format selector	The selector specified by MSTP
Region name	The name of the MST region
Revision level	The revision level of the MST region
Instance Vlans Mapped	VLAN-to-STI mappings in the MST region

display stp root

Syntax

display stp root

View

Any view

Parameters

None

Description

Use the display stp root command to display information about the root ports in the MSTP region where the device resides.

Examples

# Display information about the root ports in the MSTP region where the device resides.

<device> display stp root

MSTID Root Bridge ID ExtPathCost IntPathCost Root Port

-------- -------------------- ------------ ------------- -----------

0 32768.00e0-fc53-d908 0 200 GigabitEthernet1/0/18

Table 1-6 display stp root command output description

Field	Description
MSTID	MST instance ID in the MST region
Root Bridge ID	ID of the root bridge
ExtPathCost	Cost of the external path from the device to the root bridge
IntPathCost	Cost of the internal path from the device to the root bridge
Root Port	Root port

instance

Syntax

instance instance-id vlan vlan-list

undo instance instance-id [ vlan vlan-list ]

View

MST region view

Parameters

instance-id: ID of a spanning tree instance ranging from 0 to 16. The value of 0 refers to the CIST.

vlan-list: List of VLANs. You need to provide this argument in the form of vlan-list = { vlan-id [ to vlan-id ] }&<1-10>, where &<1-10> means that you can provide up to 10 VLAN IDs/VLAN ID ranges for this argument. Normally, a VLAN ID can be a number ranging from 1 to 4094. VLANs with their IDs beyond this range (if the device supports this kind VLAN IDs), such as VLAN 4095, VLAN 4096, can only be mapped to the CIST (spanning tree instance 0).

Description

Use the instance command to map specified VLANs to a specified spanning tree instance.

Use the undo instance command to remove the mappings from the specified VLANs to the specified spanning tree instance and remap the specified VLANs to the CIST (spanning tree instance 0). If you specify no VLAN in the undo instance command, all VLANs that are mapped to the specified spanning tree instance are remapped to the CIST.

By default, all VLANs are mapped to the CIST.

VLAN-to-MSTI mappings are recorded in the VLAN mapping table of an MSTP-enabled device. So these two commands are actually used to manipulate the VLAN mapping table. You can add/remove a VLAN to/from the VLAN mapping table of a specific spanning tree instance by using these two commands.

Note that a VLAN cannot be mapped to multiple spanning tree instances at the same time. A VLAN-to-MSTI mapping is automatically removed if you map the VLAN to another spanning tree instance.

Related commands: region-name, revision-level, vlan-mapping modulo, check region-configuration, and active region-configuration.

Examples

# Map VLAN 2 to spanning tree instance 1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp region-configuration

[device-mst-region] instance 1 vlan 2

region-name

Syntax

region-name name

undo region-name

View

MST region view

Parameters

name: MST region name to be set for the device, a string of 1 to 32 characters.

Description

Use the region-name command to set an MST region name for a device.

Use the undo region-name command to restore the MST region name to the default value.

The default MST region name of a device is its MAC address.

MST region name, along with VLAN mapping table and MSTP revision level, determines the MST region which a device belongs to.

Related commands: instance, revision-level, check region-configuration, vlan-mapping modulo, and active region-configuration.

Examples

# Set the MST region name of the device to “hello”.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp region-configuration

[device-mst-region] region-name hello

reset stp

Syntax

reset stp [ interface interface-list ]

View

User view

Parameters

Description

Use the reset stp command to clear spanning tree statistics.

The spanning tree statistics includes the numbers of TCN BPDUs, configuration BPDUs, RST BPDUs, and MST BPDUs sent/received through one or more specified ports or all ports (note that BPDUs and TCN BPDUs are counted only for CISTs.)

This command clears the spanning tree statistics on specified ports if you specify the interface-list argument. If you do not specify the interface-list argument, this command clears the spanning tree statistics on all ports.

Related commands: display stp.

Examples

# Clear the spanning tree statistics on GigabitEthernet 1/0/1 through GigabitEthernet 1/0/3.

<device> reset stp interface GigabitEthernet1/0/1 to GigabitEthernet1/0/3

revision-level

Syntax

revision-level level

undo revision-level

View

MST region view

Parameters

level: MSTP revision level to be set for the device. This argument ranges from 0 to 65,535.

Description

Use the revision-level command to set the MSTP revision level for a device.

Use the undo revision-level command to restore the revision level to the default value.

By default, the MSTP revision level of a device is 0.

MSTP revision level, along with MST region name and VLAN mapping table, determines the MST region which a device belongs to.

Related commands: instance, region-name, check region-configuration, vlan-mapping modulo, and active region-configuration.

Examples

# Set the MSTP revision level of the MST region to 5.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp region-configuration

[device-mst-region] revision-level 5

stp

Syntax

stp { enable | disable }

undo stp

View

System view, Ethernet port view

Parameters

enable: Enables MSTP globally or on a port.

disable: Disables MSTP globally or on a port.

Description

Use the stp command to enable/disable MSTP globally or on a port.

Use the undo stp command to restore the MSTP state to the default globally or on a port.

By default, MSTP is disabled.

After MSTP is enabled, the actual operating mode, which can be STP-compatible mode, RSTP-compatible mode, or MSTP mode, is determined by the user-defined protocol mode. A device becomes a transparent bridge if MSTP is disabled.

After being enabled, MSTP maintains spanning trees by processing configuration BPDUs of different VLANs. After being disabled, it stops maintaining spanning trees.

Related commands: stp mode, and stp interface.

You are not recommended to enable MSTP on GigabitEthernet 1/0/29 on the switching engine of the WX3024, GigabitEthernet 1/0/11 on the switching engine of the WX3010 or GigabitEthernet 1/0/9 on the switching engine of the WX3008.

Examples

# Enable MSTP globally.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp enable

# Disable MSTP on GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp disable

stp bpdu-protection

Syntax

stp bpdu-protection

undo stp bpdu-protection

View

System view

Parameters

None

Description

Use the stp bpdu-protection command to enable the BPDU guard function on the device.

Use the undo stp bpdu-protection command to restore to the default state of the BPDU guard function.

By default, the BPDU guard function is disabled.

Normally, the access ports of the devices operating on the access layer are directly connected to terminals (such as PCs) or file servers. These ports are usually configured as edge ports to implement rapid transition. But they resume non-edge ports automatically upon receiving configuration BPDUs, which causes spanning trees recalculation and network topology jitter.

Normally, no configuration BPDU will reach edge ports. But malicious users can attack a network by sending configuration BPDUs deliberately to edge ports to cause network jitter. You can prevent such attacks by enabling the BPDU guard function. With this function enabled on a device, the device shuts down the edge ports that receive configuration BPDUs and then reports these cases to the administrator. If an edge port is shut down, only the administrator can restore it.

Examples

# Enable the BPDU guard function.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp bpdu-protection

stp bridge-diameter

Syntax

stp bridge-diameter bridgenum

undo stp bridge-diameter

View

System view

Parameters

bridgenum: Network diameter to be set for a switched network. This argument ranges from 2 to 7.

Description

Use the stp bridge-diameter command to set the network diameter of a switched network. The network diameter of a switched network is represented by the maximum possible number of devices between any two terminal devices in a switched network.

Use the undo stp bridge-diameter command to restore the network diameter to the default value.

By default, the network diameter is 7.

After you configure the network diameter of a switched network, MSTP adjusts its hello time, forward delay, and max age settings accordingly. With the network diameter set to the default value 7, the three time-relate settings, including hello time, forward delay, and max age, are set to their default values as well.

The stp bridge-diameter command only applies to CIST. It is invalid for MSTIs.

Related commands: stp timer forward-delay, stp timer hello, and stp timer max-age.

Examples

# Set the network diameter to 5.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp bridge-diameter 5

stp compliance

Syntax

stp compliance { auto | legacy | dot1s }

undo stp compliance

View

Ethernet port view

Parameters

auto: Specifies the port to recognize and send MSTP packets in the automatic mode.

legacy: Specifies the port to recognize and send MSTP packets in the legacy mode.

dot1s: Specifies the port to recognize and send MSTP packets in the 802.1s mode.

Description

Use the stp compliance command to set the mode in which a port recognizes and sends MSTP packets.

Use the undo stp compliance command to restore the default.

By default, a port recognizes and sends MSTP packets in the automatic mode.

A port can be configured to recognize and send MSTP packets in the following modes.

l Automatic mode. Ports in this mode determine the format of the MSTP packets to be sent according to the format of the received packets.

l Legacy mode. Ports in this mode recognize/send packets in legacy format.

l 802.1s mode. Ports in this mode recognize/send packets in dot1s format.

A port acts as follows according to the format of MSTP packets forwarded by a peer device or a router.

When a port operates in the automatic mode:

l The port automatically determines the format (legacy or dot1s) of received MSTP packets and then determines the format of the packets to be sent accordingly, thus communicating with the peer devices.

l If the format of the received packets changes repeatedly, MSTP will shut down the corresponding port to prevent network storm. A port shut down in this way can only be brought up again by the network administrator.

When a port operates in the legacy mode:

l The port only recognizes and sends MSTP packets in legacy format. In this case, the port can only communicate with the peer through packets in legacy format.

l If packets in dot1s format are received, the port turns to discarding state to prevent network storm.

When a port operates in the 802.1s mode:

l The port only recognizes and sends MSTP packets in dot1s format. In this case, the port can only communicate with the peer through packets in dot1s format.

l If packets in legacy format are received, the port turns to discarding state to prevent network storm.

Examples

# Configure GigabitEthernet 1/0/1 to recognize and send MSTP packets in dot1s format.

<device> system-view

Enter system view, return to user view with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp compliance dot1s

# Restore the default mode in which a port recognizes and send MSTP packets.

[device-GigabitEthernet1/0/1] undo stp compliance

stp config-digest-snooping

Syntax

stp config-digest-snooping

undo stp config-digest-snooping

View

System view, Ethernet port view

Parameters

None

Description

Use the stp config-digest-snooping command to enable the digest snooping feature globally.

Use the undo stp config-digest-snooping command to disable the digest snooping feature globally.

The digest snooping feature is disabled by default.

According to IEEE 802.1s, two interconnected devices can interwork with each other through MSTIs in an MST region only when the two devices have the same MST region-related configuration. With MSTP enabled, interconnected devices determine whether or not they are in the same MST region by checking the configuration IDs of the BPDUs between them. (A configuration ID contains information such as region ID and configuration digest.)

As devices of some other vendors adopt proprietary spanning tree protocols, they cannot interwork with other devices in an MST region even if they are configured with the same MST region-related settings as other devices in the MST region.

This kind of problems can be overcome by implementing the digest snooping feature. If a port on the device is connected to a device of another vendor that has the same MST region-related settings but adopts a proprietary spanning tree protocol, you can enable the digest snooping feature on the port when it receives BPDU packets from a device of another vendor. Then the device considers these BPDU packets to be from its own MST region and records the configuration digests carried in the BPDU packets received from the device, which will be put in the BPDU packets to be sent to a device of another vendor. In this way, the device can interwork with devices of another vendor in an MST region.

l When the digest snooping feature is enabled on a port, the port turns to the discarding state. That is, the port stops sending BPDU packets. The port is not involved in the STP calculation until it receives BPDU packets from the peer port.

l The digest snooping feature is needed only when your device is connected to another vendor’s devices adopting proprietary spanning tree protocols.

l To enable the digest snooping feature successfully, you must first enable it on all the ports that connect to another vendor’s devices adopting proprietary spanning tree protocols and then enable it globally.

l To enable the digest snooping feature, the interconnected devices and another vendor’s devices adopting proprietary spanning tree protocols must be configured with exactly the same MST region-related configurations (including region name, revision level, and VLAN-to-MSTI mapping).

l The digest snooping feature must be enabled on all the ports on the device that connect to another vendor’s devices adopting proprietary spanning tree protocols in the same MST region.

l When the digest snooping feature is enabled globally, the VLAN-to-MSTI mapping table cannot be modified.

l The digest snooping feature is not applicable to boundary ports in an MST region.

l The digest snooping function is not applicable to edge ports in an MST region.

Examples

# Enable the digest snooping feature on GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp config-digest-snooping

[device-GigabitEthernet1/0/1] quit

[device] stp config-digest-snooping

stp cost

Syntax

stp [ instance instance-id ] cost cost

undo stp [ instance instance-id ] cost

View

Ethernet port view

Parameters

instance-id: ID of a spanning tree instance ranging from 0 to 16. The value of 0 refers to the CIST.

cost: Path cost to be set for the port. This argument ranges from 1 to 200,000.

Description

Use the stp cost command to set the path cost of the current port in a specified spanning tree instance.

Use the undo stp cost command to restore the default path cost of the current port in the specified spanning tree instance.

By default, a device automatically calculates the path costs of a port in different spanning tree instances based on a specified standard.

If you specify the instance-id argument to be 0 or do not specify this argument, the stp cost command sets the path cost of the port in CIST.

The path cost of a port affects its port role. By configuring different path costs for the same port in different MSTIs, you can make flows of different VLANs travel along different physical links, so as to achieve VLAN-based load balancing. Changing the path cost of a port in a spanning tree instance may change the role of the port in the instance and put it in state transition.

Related commands: stp interface cost.

Examples

# Set the path cost of GigabitEthernet1/0/3 in spanning tree instance 2 to 200.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/3

[device-GigabitEthernet1/0/3] stp instance 2 cost 200

stp dot1d-trap

Syntax

stp [ instance instance-id ] dot1d-trap [ newroot | topologychange ] enable

undo stp [ instance instance-id ] dot1d-trap [ newroot | topologychange ] enable

View

System view

Parameters

instance-id: Spanning tree instance ID ranging from 0 to 16. The value of 0 refers to CIST. With this argument specified, the trap messages sent are only of the spanning tree instance identified by this argument.

newroot: Sends trap messages conforming to 802.1d standard to the network management device when the device becomes the root bridge of an instance.

topologychange: Sends trap messages conforming to 802.1d standard to the network management device when the device detects network topology changes.

Description

Use the stp dot1d-trap command to enable a device to send trap messages conforming to 802.1d standard when MSTP network topology changes.

Use the undo stp dot1d-trap command to disable this function.

A device sends trap messages conforming to 802.1d standard to the network management device when:

l The device becomes the root bridge of a spanning tree instance.

l Network topology changes are detected.

Examples

# Enable a device to send trap messages conforming to 802.1d standard to the network management device when the device becomes the root bridge of spanning tree instance 1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp instance 1 dot1d-trap newroot enable

stp edged-port

Syntax

stp edged-port { enable | disable }

undo stp edged-port

View

Ethernet port view

Parameters

enable: Configures the current Ethernet port as an edge port.

disable: Configures the current Ethernet port as a non-edge port.

Description

Use the stp edged-port enable command to configure the current Ethernet port as an edge port.

Use the stp edged-port disable command to configure the current Ethernet port as a non-edge port.

Use the undo stp edged-port command to restore the current Ethernet port to its default state.

By default, all Ethernet ports of a device are non-edge ports.

An edge port is a port that is directly connected to a user terminal instead of another device or shared network segment. Rapid transition to the forwarding state is applied to edge ports because on these ports no loops can be incurred by network topology changes. You can enable a port to turn to the forwarding state rapidly by setting it to an edge port. And you are recommended to configure the Ethernet ports directly connected to user terminals as edge ports to enable them to turn to the forwarding state rapidly.

Normally, configuration BPDUs cannot reach an edge port because the port is not connected to another device. But when the BPDU guard function is disabled on an edge port, configuration BPDUs sent deliberately by a malicious user may reach the port. If an edge port receives a BPDU, it turns to a non-edge port.

Related commands: stp interface edged-port.

With the loop guard function enabled, the root guard function and the edge port configuration are mutually exclusive.

Examples

# Configure GigabitEthernet 1/0/1 as a non-edge port.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp edged-port disable

stp interface

Syntax

stp interface interface-list { enable | disable }

View

System view

Parameters

enable: Enables MSTP on the specified ports.

disable: Disables MSTP on the specified ports.

Description

Use the stp interface command to enable or disable MSTP on specified ports in system view.

By default, MSTP is enabled on the ports of a device if MSTP is globally enabled on the device, and MSTP is disabled on the ports if MSTP is globally disabled.

An MSTP-disabled port does not participate in any spanning tree calculation and is always in the forwarding state.

Disabling MSTP on ports may result in loops.

Related commands: stp mode, and stp.

Examples

# Enable MSTP on GigabitEthernet 1/0/1 in system view.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/1 enable

stp interface compliance

Syntax

stp interface interface-list compliance { auto | legacy | dot1s }

undo stp interface interface-list compliance

View

System view

Parameters

interface-list: Ethernet port list. You can specify multiple Ethernet ports by providing this argument in the format of interface-list ={ interface-type interface-number [ to interface-type interface-number ] } &<1-10>, where &<1-10> means that you can provide up to 10 port indexes/port index ranges for this argument.

auto: Specifies the port to recognize and send MSTP packets in the automatic mode.

legacy: Specifies the port to recognize and send MSTP packets in the legacy mode.

dot1s: Specifies the port to recognize and send MSTP packets in the 802.1s mode.

Description

Use the stp interface compliance command to set the mode in which a port recognizes and sends MSTP packets.

Use the undo stp interface compliance command to restore the default.

By default, a port recognizes and sends MSTP packets in the automatic mode.

A port can be configured to recognize and send MSTP packets in the following modes.

l Automatic mode. Ports in this mode determine the format of the MSTP packets to be sent according to the format of the received packets.

l Legacy mode. Ports in this mode recognize/send packets in legacy format.

l 802.1s mode. Ports in this mode recognize/send packets in dot1s format.

A port acts as follows according to the format of MSTP packets forwarded by a peer device or a router.

When a port operates in the automatic mode:

When a port operates in the legacy mode:

l The port only recognizes and sends MSTP packets in legacy format. In this case, the port can only communicate with the peer through packets in legacy format.

l If packets in dot1s format are received, the port turns to discarding state to prevent network storm.

When a port operates in the 802.1s mode:

l The port only recognizes and sends MSTP packets in dot1s format. In this case, the port can only communicate with the peer through packets in dot1s format.

l If packets in legacy format are received, the port turns to discarding state to prevent network storm.

Examples

# Configure GigabitEthernet 1/0/1 to recognize and send MSTP packets in dot1s format.

<device> system-view

System view, return to user view with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/1 compliance dot1s

# Restore the default mode in which a port recognizes and send MSTP packets.

[device] undo stp interface GigabitEthernet1/0/1 compliance

stp interface config-digest-snooping

Syntax

stp interface interface-list config-digest-snooping

undo stp interface interface-list config-digest-snooping

View

System view

Parameters

Description

Use the stp interface config-digest-snooping command to enable the digest snooping feature on specific ports.

Use the undo stp interface config-digest-snooping command to disable the digest snooping feature on specific ports.

By default, the digest snooping feature is disabled on a port.

According to IEEE 802.1s, two interconnected MSTP devices can interwork with each other through MSTIs in an MST region only when the two devices have the same MST region-related configuration. Interconnected MSTP devices determine whether or not they are in the same MST region by checking the configuration IDs of the BPDUs between them. (A configuration ID contains information such as region ID and configuration digest.)

As devices of some vendors adopt proprietary spanning tree protocols, they cannot interwork with other devices in an MST region even if they are configured with the same MST region-related settings as other devices in the MST region.

This kind of problems can be overcome by implementing the digest snooping feature. If a port on the device is connected to a device of another vendor that has the same MST region-related settings but adopts a proprietary spanning tree protocol, you can enable the digest snooping feature on the port when it receives BPDU packets from a device of another vendor. Then the device considers these BPDU packets to be from its own MST region and records the configuration digests carried in the BPDU packets received from the device, which will be put in the BPDU packets to be sent to the device of another vendor. In this way, the device can interwork with another vendor’s devices in an MST region.

l The digest snooping feature is needed only when your device is connected to another vendor’s devices adopting proprietary spanning tree protocols.

l To enable the digest snooping feature successfully, you must first enable it on all the ports on the device that connect to another vendor’s devices adopting proprietary spanning tree protocols and then enable it globally.

l The digest snooping feature must be enabled on all the ports connecting to another vendor’s device adopting proprietary spanning tree protocols in the same MST region.

l When the digest snooping feature is enabled globally, the VLAN-to-MSTI mapping table cannot be modified.

l The digest snooping feature is not applicable to boundary ports in an MST region.

l The digest snooping function is not applicable to edge ports in an MST region.

Examples

# Enable the digest snooping feature for GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet 1/0/1 config-digest-snooping

stp interface cost

Syntax

stp interface interface-list [ instance instance-id ] cost cost

undo stp interface interface-list [ instance instance-id ] cost

View

System view

Parameters

instance-id: Spanning tree instance ID ranging from 0 to 16. The value of 0 refers to the CIST.

cost: Port path cost to be set. This argument ranges from 1 to 200,000.

Description

Use the stp interface cost command to set the path cost(s) of the specified port(s) in a specified spanning tree instance in system view.

Use the undo stp interface cost command to restore the default value of the path cost(s) of the specified port(s) in the specified spanning tree instance in system view.

By default, a device automatically calculates the path costs of a port in different spanning tree instances based on a specified standard.

If you specify the instance-id argument to be 0 or do not specify this argument, the stp interface cost command sets the path cost(s) of the specified port(s) in the CIST.

The default port path cost varies with port speed. Refer to Table 1-7 for details.

Related commands: stp cost.

Examples

# Set the path cost of GigabitEthernet 1/0/3 in spanning tree instance 2 to 400.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/3 instance 2 cost 400

stp interface edged-port

Syntax

stp interface interface-list edged-port { enable | disable }

undo stp interface interface-list edged-port

View

System view

Parameters

enable: Configures the specified Ethernet port to be an edge port.

disable: Configures the specified Ethernet port to be a non-edge port.

Description

Use the stp interface edged-port enable command to configure the specified Ethernet ports as edge ports in system view.

Use the stp interface edged-port disable command to configure the specified Ethernet ports as non-edge ports in system view.

Use the undo stp interface edged-port command to restore the specified Ethernet ports to the default state.

By default, all Ethernet ports of a device are non-edge ports.

An edge port is a port that is directly connected to a user terminal instead of another device or a network segment. Rapid transition to the forwarding state is applied to edge ports because on these ports no loops can be incurred by network topology changes. You can enable a port to turn to the forwarding state rapidly by setting it to an edge port. And you are recommended to configure the Ethernet ports directly connected to user terminals as edge ports to enable them to turn to the forwarding state rapidly.

Related commands: stp edged-port.

With the loop guard function enabled, the root guard function and the edge port configuration are mutually exclusive.

Examples

# Configure GigabitEthernet 1/0/3 as an edge port.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/3 edged-port enable

stp interface loop-protection

Syntax

stp interface interface-list loop-protection

undo stp interface interface-list loop-protection

View

System view

Parameters

Description

Use the stp interface loop-protection command to enable the loop guard function in system view.

Use the undo stp interface loop-protection command to restore the default state of the loop guard function in system view.

The loop guard function is disabled by default.

Related commands: stp loop-protection.

With the loop guard function enabled, the root guard function and the edge port configuration are mutually exclusive.

Examples

# Enable the loop guard function for GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/1 loop-protection

stp interface mcheck

Syntax

stp [ interface interface-list ] mcheck

View

System view

Parameters

Description

Use the stp interface mcheck command to perform the mCheck operation on specified port(s) in system view.

A port on an MSTP-enabled device migrates to the STP-/RSTP-compatible mode automatically if an STP-/RSTP-enabled device has been connected to it. But when the STP-/RSTP-enabled device is disconnected from the port, the port cannot migrate back to the MSTP mode automatically. In this case, you can force the port to migrate to the MSTP mode by performing the mCheck operation on the port.

Related commands: stp mcheck, and stp mode.

Examples

# Perform the mCheck operation for GigabitEthernet 1/0/3 in system view.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/3 mcheck

stp interface no-agreement-check

Syntax

stp interface interface-type interface-number no-agreement-check

undo stp interface interface-type interface-number no-agreement-check

View

System view

Parameters

interface-type: Port type.

interface-number: Port number.

Description

Use the stp interface no-agreement-check command to enable the rapid transition feature on the specified port.

Use the undo stp interface no-agreement-check command to disable the rapid transition feature on the specified port.

The rapid transition feature is disabled on any port by default.

Some vendors' devices adopt proprietary spanning tree protocols that are similar to RSTP in the way to implement rapid transition on designated ports. When a device of this kind operates as the upstream device of a WX3000 series device running MSTP, the upstream designated port fails to change their states rapidly.

The rapid transition feature is developed on the WX3000 series devices to avoid this case. When a WX3000 series device running MSTP is connected in the upstream direction to a device of another vendor adopting proprietary spanning tree protocols, you can enable the rapid transition feature on the ports of the WX3000 series device operating as the downstream device. Among these ports, those operating as the root ports will then send agreement packets to their upstream ports after they receive proposal packets from the upstream designated ports, instead of waiting for agreement packets from the upstream device. This enables designated ports of the upstream device to change their states rapidly.

Related commands: stp no-agreement-check.

l The rapid transition feature can be enabled on root ports or alternate ports only.

l You can enable the rapid transition feature on the designated port, however, the feature does not take effect on the port.

Examples

# Enable the rapid transition feature for GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device]stp interface GigabitEthernet1/0/1 no-agreement-check

stp interface point-to-point

Syntax

stp interface interface-list point-to-point { force-true | force-false | auto }

undo stp interface interface-list point-to-point

View

System view

Parameters

force-true: Specifies that the links connected to the specified Ethernet ports are point-to-point links.

force-false: Specifies that the links connected to the specified Ethernet ports are not point-to-point links.

auto: Specifies to automatically determine whether or not the links connected to the specified Ethernet ports are point-to-point links.

Description

Use the stp interface point-to-point command to specify whether the links connected to the specified Ethernet ports are point-to-point links in system view.

Use the undo stp interface point-to-point command to restore the links connected to the specified ports to their default link types, which are automatically determined by MSTP.

If no keyword is specified in the stp interface point-to-point command, the auto keyword is used by default, and so MSTP automatically determines the types of the links connected to the specified ports.

The rapid transition feature is not applicable to ports connected to non-point-to-point links.

If an Ethernet port is the master port of aggregated ports or operates in full-duplex mode, the link connected to the port is a point-to-point link. You are recommended to let MSTP automatically determine the link types.

These two commands apply to CIST and MSTIs. If you configure the link to which a port is connected to be a point-to-point link (or a non-point-to-point link), the configuration applies to all spanning tree instances (that is, the port is configured to connect to a point-to-point link (or a non-point-to-point link) in all spanning tree instances). If the actual physical link is not a point-to-point link and you configure the link to which the port is connected to be a point-to-point link, loops may temporarily occur.

Related commands: stp point-to-point.

Examples

# Configure the link connected to GigabitEthernet 1/0/3 as a point-to-point link.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/3 point-to-point force-true

stp interface port priority

Syntax

stp interface interface-list instance instance-id port priority priority

undo stp interface interface-list instance instance-id port priority

View

System view

Parameters

instance-id: Spanning tree instance ID ranging from 0 to 16. The value of 0 refers to the CIST.

priority: Port priority to be set. This argument ranges from 0 to 240 and must be a multiple of 16 (such as 0, 16, 32, and so on).

Description

Use the stp interface port priority command to set a port priority for the specified ports in the specified spanning tree instance in system view.

Use the undo stp interface port priority command to restore the default priority of the specified ports in the specified spanning tree instance in system view.

The default port priority of a port in a spanning tree instance is 128.

If you specify the instance-id argument to 0, the two commands apply to the port priorities on the CIST. The role a port plays in a spanning tree instance is affected by its port priority in the instance. A port on an MSTP-enabled device can have different port priorities and play different roles in different MSTIs. This enables packets of different VLANs to be forwarded along different physical paths, so as to implement VLAN-based load balancing. Changing port priorities results in port role recalculation and may cause state transition.

Related commands: stp port priority.

Examples

# Set the port priority of GigabitEthernet 1/0/3 in spanning tree instance 2 to 16.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/3 instance 2 port priority 16

stp interface root-protection

Syntax

stp interface interface-list root-protection

undo stp interface interface-list root-protection

View

System view

Parameters

Description

Use the stp interface root-protection command to enable the root guard function on specified port(s) in system view.

Use the undo stp interface root-protection command to restore the root guard function to the default state on specified port(s) in system view.

By default, the root guard function is disabled.

Because of configuration errors or malicious attacks, the root bridge in the network may receive configuration BPDUs with priorities higher than that of a root bridge, which causes new root bridge to be elected and network topology jitter to occur. In this case, flows that should have traveled along high-speed links are led to low-speed links, which causes network congestion.

You can avoid this problem by enabling the root guard function. Root-guard-enabled ports can only be kept as designated ports in all spanning tree instances. When a port of this type receives configuration BPDUs with higher priorities, that is, when it is to become a non-designated port, it turns to the discarding state and stops forwarding packets (as if it is disconnected from the link). It resumes the normal state if it does not receive any configuration BPDUs with higher priorities for a specified period.

Related commands: stp root-protection.

With the loop guard function enabled, the root guard function and edge port configuration are mutually exclusive.

Examples

# Enable the root guard function for GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/1 root-protection

stp interface transmit-limit

Syntax

stp interface interface-list transmit-limit packetnum

undo stp interface interface-list transmit-limit

View

System view

Parameters

packetnum: Maximum number of configuration BPDUs a port can send in each hello time. This argument ranges from 1 to 255 and defaults to 10.

Description

Use the stp interface transmit-limit command to set the maximum number of configuration BPDUs each specified port can send in each hello time.

Use the undo stp interface transmit-limit command to restore the maximum number to the default value.

The larger the packetnum argument is, the more packets a port can transmit in each hello time, and the more resources on the device are occupied. Configure the packetnum argument to a proper value to limit the number of BPDUs a port can send in each hello time to prevent MSTP from occupying too much bandwidth resources when network topology jitter occur.

Related commands: stp transmit-limit.

Examples

# Set the maximum transmitting speed of GigabitEthernet 1/0/3 to 15.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp interface GigabitEthernet1/0/3 transmit-limit 15

stp loop-protection

Syntax

stp loop-protection

undo stp loop-protection

View

Ethernet port view

Parameters

None

Description

Use the stp loop-protection command to enable the loop guard function on the current port.

Use the undo stp loop-protection command to restore the loop guard function to the default state on the current port.

By default, the loop guard function is disabled.

A device maintains the states of the root port and other blocked ports by receiving and processing BPDUs from the upstream device. These BPDUs may get lost because of network congestion or unidirectional link failures. If a device does not receive BPDUs from the upstream device for a certain period, the device selects a new root port; the original root port becomes a designated port; and the blocked ports turn to the forwarding state. This may cause loops in the network.

The loop guard function suppresses loops. With this function enabled, if link congestions or unidirectional link failures happen, a root port becomes a designated port, and the port turns to the discarding state. The blocked port also becomes the designated port and the port turns to the discarding state, that is, the port does not forward packets and thereby loops can be prevented.

Examples

# Enable the loop guard function on GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp loop-protection

stp max-hops

Syntax

stp max-hops hops

undo stp max-hops

View

System view

Parameters

hops: Maximum hop count to be set. This argument ranges from 1 to 40.

Description

Use the stp max-hops command to set the maximum hop count for the MST region the current device belongs to.

Use the undo stp max-hops command to restore the maximum hop count to the default.

By default, the maximum hop count of an MST region is 20.

The maximum hop count configured on the region roots of an MST region limits the size of the MST region.

A configuration BPDU contains a field that maintains the remaining hops of the configuration BPDU. And a device discards the configuration BPDUs whose remaining hops are 0. After a configuration BPDU reaches a root bridge of a spanning tree in a MST region, the value of the remaining hops field in the configuration BPDU is decreased by 1 every time the configuration BPDU passes one device. Such a mechanism disables the devices that are beyond the maximum hops from participating in spanning tree calculation, and thus limits the size of an MST region.

With such a mechanism, the maximum hops configured on the device operating as the root bridge of the CIST or an MSTI in a MST region becomes the network diameter of the spanning tree, which limits the size of the spanning tree in the current MST region. The devices that are not root bridges in an MST region adopt the maximum hop settings of the root bridge.

Examples

# Set the maximum hop count of the current MST region to 35.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp max-hops 35

stp mcheck

Syntax

stp mcheck

View

System view, Ethernet port view

Parameters

None

Description

Use the stp mcheck command to perform the mCheck operation on the current port.

When a port on an MSTP-enabled upstream device connects with an STP-enabled downstream device, the port operates in the STP-compatible mode automatically. But when the STP-enabled downstream device is then replaced by an MSTP-enabled device, the port cannot automatically transit to the MSTP mode but still remains in the STP-compatible mode. In this case, you can force the port to transit to the MSTP mode by performing the mCheck operation on the port.

Similarly, when a port on an RSTP-enabled upstream device connects with an STP-enabled downstream device, the port operates in the STP-compatible mode. But when the STP-enabled downstream device is then replaced by an MSTP-enabled device, the port cannot automatically transit to the RSTP mode but remains in the STP-compatible mode. In this case, you can force the port to transit to the RSTP mode by performing the mCheck operation on the port.

Related commands: stp mode, and stp interface mcheck.

Examples

# Perform the mCheck operation on GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp mcheck

stp mode

Syntax

stp mode { stp | rstp | mstp }

undo stp mode

View

System view

Parameters

stp: Specifies the STP-compatible mode.

mstp: Specifies the MSTP mode.

rstp: Specifies the RSTP-compatible mode.

Description

Use the stp mode command to set the operating mode of an MSTP-enabled device.

Use the undo stp mode command to restore the default operating mode of an MSTP-enabled device.

By default, an MSTP-enabled device operates in MSTP mode.

To make a device compatible with STP and RSTP, MSTP provides following three operating modes.

l STP-compatible mode, where the ports of a device send STP BPDUs to neighboring devices. If STP-enabled devices exist in a switched network, you can use the stp mode stp command to configure an MSTP-enabled device to operate in STP-compatible mode.

l RSTP-compatible mode, where the ports of a device send RSTP BPDUs to neighboring devices. If RSTP-enabled devices exist in a switched network, you can use the stp mode rstp command to configure an MSTP-enabled device to operate in RSTP-compatible mode.

l MSTP mode, where the ports of a device send MSTP BPDUs and STP BPDUs (if the device is connected to STP-enabled devices) to neighboring devices. In this case, the device is MSTP-capable.

Related commands: stp mcheck, stp, stp interface, and stp interface mcheck.

Examples

# Configure the MSTP operation mode as STP-compatible.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp mode stp

stp no-agreement-check

Syntax

stp no-agreement-check

undo stp no-agreement-check

View

Ethernet port view

Parameters

None

Description

Use the stp no-agreement-check command to enable the rapid transition feature on a port.

Use the stp no-agreement-check command to disable the rapid transition feature.

By default, the rapid transition feature is disabled on a port.

Some vendors’ devices adopt proprietary spanning tree protocols that are similar to RSTP in the way to implement rapid transition on designated ports. When a device of this kind operates as the upstream device of a WX3000 series device running MSTP, the upstream designated port fails to change their states rapidly.

The rapid transition feature aims to resolve this problem. When a WX3000 series device running MSTP is connected in the upstream direction to a device of another vendor adopting proprietary spanning tree protocols, you can enable the rapid transition feature on the ports of the WX3000 series device operating as the downstream device. Among these ports, those operating as the root ports will then actively send agreement packets to their upstream ports after they receive proposal packets from the upstream designated ports, instead of waiting for agreement packets from the upstream device. This enables designated ports of the upstream device to change their states rapidly.

Related commands: stp interface no-agreement-check.

l The rapid transition feature can be enabled on only root ports or alternate ports.

l You can enable the rapid transition feature on the designated port. However, the feature does not take effect on the port.

Examples

# Enable the rapid transition feature on GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp no-agreement-check

stp pathcost-standard

Syntax

stp pathcost-standard { dot1d-1998 | dot1t | legacy }

undo stp pathcost-standard

View

System view

Parameters

dot1d-1998: Uses the IEEE 802.1D-1998 standard to calculate the default path costs of ports.

dot1t: Uses the IEEE 802.1t standard to calculate the default path costs of ports.

legacy: Uses the proprietary standard to calculate the default path costs of ports.

Description

Use the stp pathcost-standard command to set the standard to be used to calculate the default path costs of the links connected to the device.

Use the undo stp pathcost-standard command to specify to use the default standard.

By default, a device uses the legacy standard to calculate the default path costs of ports.

Table 1-7 Link speeds and the corresponding path costs

Link speed	Operating mode (half-/full-duplex)	802.1D-1998	IEEE 802.1t	Proprietary standard
0	—	65,535	200,000,000	200,000
10 Mbps	Half-duplex/Full-duplex Aggregated link 2 ports Aggregated link 3 ports Aggregated link 4 ports	100 95 95 95	200,000 1,000,000 666,666 500,000	2,000 1,800 1,600 1,400
100 Mbps	Half-duplex/Full-duplex Aggregated link 2 ports Aggregated link 3 ports Aggregated link 4 ports	19 15 15 15	200,000 100,000 66,666 50,000	200 180 160 140
1,000 Mbps	Full-duplex Aggregated link 2 ports Aggregated link 3 ports Aggregated link 4 ports	4 3 3 3	200,000 10,000 6,666 5,000	20 18 16 14
10 Gbps	Full-duplex Aggregated link 2 ports Aggregated link 3 ports Aggregated link 4 ports	2 1 1 1	200,000 1,000 666 500	2 1 1 1

Link speed

Operating mode (half-/full-duplex)

802.1D-1998

IEEE 802.1t

Proprietary standard

—

65,535

200,000,000

200,000

10 Mbps

Half-duplex/Full-duplex

Aggregated link 2 ports

Aggregated link 3 ports

Aggregated link 4 ports

100

200,000

1,000,000

666,666

500,000

2,000

1,800

1,600

1,400

100 Mbps

Half-duplex/Full-duplex

Aggregated link 2 ports

Aggregated link 3 ports

Aggregated link 4 ports

200,000

100,000

66,666

50,000

200

180

160

140

1,000 Mbps

Full-duplex

Aggregated link 2 ports

Aggregated link 3 ports

Aggregated link 4 ports

200,000

10,000

6,666

5,000

10 Gbps

Full-duplex

Aggregated link 2 ports

Aggregated link 3 ports

Aggregated link 4 ports

200,000

1,000

666

500

If you modify the previous STP path cost (for example, change the path cost standard from legacy to 802.1t), the previous path cost configuration on the port gets lost.

Normally, when a port operates in full-duplex mode, the corresponding path cost is slightly less than that when the port operates in half-duplex mode.

When the path cost of an aggregated link is calculated, the 802.1D-1998 standard does not take the number of the ports on the aggregated link into account, whereas the 802.1T standard does. The following formula is used to calculate the path cost of an aggregated link:

Path cost = 200,000 / link speed,

In this formula, the link speed is the sum of the speeds of the unblocked ports on the aggregated link, which is measured in 100 Kbps.

Examples

# Configure to use the IEEE 802.1D-1998 standard to calculate the default path costs of ports

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp pathcost-standard dot1d-1998

# Configure to use the IEEE 802.1t standard to calculate the default path costs of ports.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp pathcost-standard dot1t

stp point-to-point

Syntax

stp point-to-point { force-true | force-false | auto }

undo stp point-to-point

View

Ethernet port view

Parameters

force-true: Specifies that the link connected to the current Ethernet port is a point-to-point link.

force-false: Specifies that the link connected to the current Ethernet port is not a point-to-point link.

auto: Specifies to automatically determine whether or not the link connected to the current Ethernet port is a point-to-point link.

Description

Use the stp point-to-point command to specify whether the link connected to the current Ethernet port is a point-to-point link.

Use the undo stp point-to-point command to restore the link connected to the current Ethernet port to its default link type, which is automatically determined by MSTP.

By default, whether the link type of a port is point-to-point is automatically determined by the device.

If no keyword is specified in the stp point-to-point command, the auto keyword is used by default, and so MSTP automatically determines the type of the link connected to the current port.

The rapid transition feature is not applicable to ports on non-point-to-point links.

If an Ethernet port is the master port of aggregation ports or operates in full-duplex mode, the link connected to the port is a point-to-point link. You are recommended to let MSTP automatically determine the link types of ports.

The two commands only apply to CISTs and MSTIs. If you configure the link to which a port is connected is a point-to-point link (or a non-point-to-point link), the configuration applies to all spanning tree instances (that is, the port is configured to connect to a point-to-point link (or a non-point-to-point link) in all spanning tree instances). If the actual physical link is not a point-to-point link and you configure the link to which the port is connected to be a point-to-point link, temporary loops may occur.

Related commands: stp interface point-to-point.

Examples

# Configure the link connected to GigabitEthernet 1/0/3 as a point-to-point link.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/3

[device-GigabitEthernet1/0/3] stp point-to-point force-true

stp port priority

Syntax

stp [ instance instance-id ] port priority priority

undo stp [ instance instance-id ] port priority

View

Ethernet port view

Parameters

instance-id: Spanning tree instance ID ranging from 0 to 16. The value of 0 refers to the CIST.

port priority priority: Sets the port priority. The priority argument ranges from 0 to 240 and must be a multiple of 16 (such as 0, 16, and 32).

Description

Use the stp port priority command to set the port priority of the current port in the specified spanning tree instance.

Use the undo stp port priority command to restore the default port priority of the current port in the specified spanning tree instance.

The default port priority of a port in any spanning tree instance is 128.

If you specify the instance-id argument to 0 or do not specify the argument, the two commands apply to the port priorities of ports on the CIST. The role a port plays in a spanning tree instance is determined by the port priority in the instance. A port on a MSTP-enabled device can have different port priorities and play different roles in different MSTIs. This enables packets of different VLANs to be forwarded along different physical links, so as to implement VLAN-based load balancing. Changing port priorities result in port role recalculation and state transition.

Related commands: stp interface port priority.

Examples

# Set the port priority of GigabitEthernet 1/0/3 in spanning tree instance 2 to 16.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/3

[device-GigabitEthernet1/0/3] stp instance 2 port priority 16

stp portlog

Syntax

stp [ instance instance-id ] portlog

undo stp [ instance instance-id ] portlog

View

System view

Parameters

instance instance-id: Specifies a spanning tree instance ID, ranging from 0 to 16. The value of 0 indicates the CIST.

Description

Use the stp portlog command to enable log and trap message output for the ports of a specified instance.

Use the undo stp portlog command to disable this function.

By default, log and trap message output is disabled.

Executing the stp portlog command (without using the instance instance-id parameters) will enable log and trap message output for the ports of instance 0.

Examples

# Enable log and trap message output for the ports of instance 1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp instance 1 portlog

stp portlog all

Syntax

stp portlog all

undo stp portlog all

View

System view

Parameters

None

Description

Use the stp portlog all command to enable log and trap message output for the ports of all instances.

Use the undo stp portlog all command to disable this function.

By default, log and trap message output is disabled on the ports of all instances.

Examples

# Enable log and trap message output for the ports of all instances.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp portlog all

stp priority

Syntax

stp [ instance instance-id ] priority priority

undo stp [ instance instance-id ] priority

View

System view

Parameters

instance-id: Spanning tree instance ID ranging from 0 to 16. The value of 0 refers to the CIST.

priority: Switch priority to be set. This argument ranges from 0 to 61,440 and must be a multiple of 4,096 (such as 0, 4,096, and 8,192). There are totally 16 available device priorities.

Description

Use the stp priority command to set the priority of the device in the specified spanning tree instance.

Use the undo stp priority command to restore the device priority to the default priority in the specified spanning tree instance.

The default priority of a device is 32,768.

The priorities of devices are used for spanning tree calculation. Device priorities are spanning tree-specific. That is, you can set different priorities for the same device in different spanning tree instances.

If you do not specify the instance-id argument, the two commands apply to only the CIST.

Examples

# Set the bridge priority of the device in spanning tree instance 1 to 4,096.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp instance 1 priority 4096

stp region-configuration

Syntax

stp region-configuration

undo stp region-configuration

View

System view

Parameters

None

Description

Use the stp region-configuration command to enter MST region view.

Use the undo stp region-configuration command to restore the MST region-related settings to the default.

MST region-related parameters include: region name, revision level, and VLAN mapping table. By default:

l MST region name is the first MAC address of the device

l All VLANs are mapped to the CIST in the VLAN mapping table

l The MSTP revision level is 0

You can modify the three parameters after entering MST region view by using the stp region-configuration command.

Examples

# Enter MST region view.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp region-configuration

[device-mst-region]

stp root primary

Syntax

stp [ instance instance-id ] root primary [ bridge-diameter bridgenum [ hello-time centi-seconds ] ]

undo stp [ instance instance-id ] root

View

System view

Parameters

instance-id: Spanning tree instance ID ranging from 0 to 16. The value of 0 refers to the CIST.

bridgenum: Network diameter of the specified spanning tree. This argument ranges from 2 to 7 and defaults to 7.

centi-seconds: Hello time in centiseconds of the specified spanning tree. This argument ranges from 100 to 1,000 and defaults to 200.

Description

Use the stp root primary command to configure the current device as the root bridge of a specified spanning tree instance.

Use the undo stp root command to cancel the current configuration.

By default, a device is not configured as a root bridge.

If you do not specify the instance-id argument, these two commands apply to only the CIST.

You can specify the current device as the root bridge of a spanning tree instance regardless of the priority of the device. You can also specify the network diameter of the switched network by using the stp root primary command. The device will then figure out the following three time parameters: hello time, forward delay, and max age. As the hello time figured out by the network diameter is not always the optimal one, you can set it manually through the hello-time centi-seconds parameter. Generally, you are recommended to obtain the forward delay and max age parameters through setting the network diameter.

l You can configure only one root bridge for a spanning tree instance and can configure one or more secondary root bridges for a spanning tree instance. Specifying multiple root bridges for a spanning tree instance causes unpredictable spanning tree calculation results.

l Once a device is configured as the root bridge or a secondary root bridge, its priority cannot be modified.

Examples

# Configure the current device as the root bridge of spanning tree instance 1, set the network diameter of the switched network to 4, and set the hello time to 500 centiseconds.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp instance 1 root primary bridge-diameter 4 hello-time 500

stp root secondary

Syntax

stp [ instance instance-id ] root secondary [ bridge-diameter bridgenum [ hello-time centi-seconds ] ]

undo stp [ instance instance-id ] root

View

System view

Parameters

instance-id: Spanning tree instance ID ranging from 0 to 16. The value of 0 refers to the CIST.

bridgenum: Network diameter of the specified spanning tree. This argument ranges from 2 to 7 and defaults to 7.

centi-seconds: Hello time in centiseconds of the specified spanning tree. This argument ranges from 100 to 1,000 and defaults to 200.

Description

Use the stp root secondary command to configure the current device as a secondary root bridge of a specified spanning tree instance.

Use the undo stp root command to cancel the current configuration.

By default, a device does not operate as a secondary root bridge.

If you do not specify the instance-id argument, the two commands apply to only the CIST.

You can configure one or more secondary root bridges for a spanning tree instance. If the device operating as the root bridge fails or is turned off, the secondary root bridge with the least MAC address becomes the root bridge.

You can specify the network diameter and the hello time of the device when you are configuring it as a secondary root bridge. The device will then figure out the other two time parameters: forward delay and max age. If the instance-id argument is specified to 0 in this command, the current device is configured as the secondary root bridge of the CIST. You can configure only one root bridge for a spanning tree instance but you can configure one or more secondary root bridges for a spanning tree instance.

Once a device is configured as the root bridge or a secondary root bridge, its priority cannot be modified.

Examples

# Configure the current device as a secondary root bridge of spanning tree instance 4, setting the network diameter of the switched network to 5 and the hello time of the current device to 300 centiseconds.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp instance 4 root secondary bridge-diameter 5 hello-time 300

stp root-protection

Syntax

stp root-protection

undo stp root-protection

View

Ethernet port view

Parameters

None

Description

Use the stp root-protection command to enable the root guard function on the current device.

Use the undo stp root-protection command to restore the root guard function to the default state on the current device.

By default, the root guard function is disabled.

Because of configuration errors or malicious attacks, the valid root bridge in the network may receive configuration BPDUs with their priorities higher than that of the root bridge, which causes new root bridge to be elected and network topology jitter to occur. In this case, flows that should have traveled along high-speed links are led to low-speed links, causing network congestion.

You can avoid this problem by utilizing the root guard function. Root-guard-enabled ports can only be kept as designated ports in all spanning tree instances. When a port of this type receives configuration BPDUs with higher priorities, it turns to the discarding state before it is specified as a non-designated port and stops forwarding packets (as if it is disconnected from the link). It resumes the normal state if it does not receive any configuration BPDUs with higher priorities for a specified period.

Related commands: stp interface root-protection.

Examples

# Enable the root guard function on GigabitEthernet 1/0/1.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp root-protection

stp tc-protection

Syntax

stp tc-protection enable

stp tc-protection disable

View

System view

Parameters

None

Description

Use the stp tc-protection enable command to enable the TC-BPDU attack guard function.

Use the stp tc-protection disable command to disable the TC-BPDU attack guard function.

By default, the TC-BPDU guard attack function is enabled, and the MAC address table and ARP entries can be removed for up to six times within 10 seconds.

Normally, a device removes the MAC address table and ARP entries upon receiving TC-BPDUs. If a malicious user sends a large amount of TC-BPDUs to a device in a short period, the device may be busy in removing the MAC address table and ARP entries frequently, which may affect spanning tree calculation, occupy large amount of bandwidth and increase device CPU utilization.

With the TC-BPDU attack guard function enabled, a device performs a removing operation upon receiving a TC-BPDU and triggers a timer (set to 10 seconds by default) at the same time. Before the timer expires, the device only performs the removing operation for limited times (up to six times by default) regardless of the number of the TC-BPDUs it receives. Such a mechanism prevents a device from being busy in removing the MAC address table and ARP entries.

Examples

# Enable the TC-BPDU attack guard function on the device.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp tc-protection enable

stp tc-protection threshold

Syntax

stp tc-protection threshold number

undo stp tc-protection threshold

View

System view

Parameters

number: Maximum number of times that a device can remove the MAC address table and ARP entries within each 10 seconds, in the range of 1 to 255.

Description

Use the stp tc-protection threshold command to set the maximum number of times that a device can remove the MAC address table and ARP entries within each 10 seconds.

Use the undo stp tc-protection threshold command to restore the default.

Normally, a device removes the MAC address table and ARP entries upon receiving a TC-BPDU. If a malicious user sends large amount of TC-BPDUs to a device in a short period, the device may be busy in removing the MAC address table and ARP entries, which may affect spanning tree calculation, occupy a large amount of bandwidth and increase CPU utilization of the device.

You can use the stp tc-protection threshold command to set the maximum times for a device to remove the MAC address table and ARP entries in a specific period. When the number of the TC-BPDUs received within a period is less than the maximum times, the device performs a removing operation upon receiving a TC-BPDU. After the number of the TC-BPDUs received reaches the maximum times, the device stops performing the removing operation. For example, if you set the maximum times for a device to remove the MAC address table and ARP entries to 100 and the device receives 200 TC-BPDUs in the period, the device removes the MAC address table and ARP entries for only 100 times within the period.

Examples

# Set the maximum times for a device to remove the MAC address table and ARP entries within 10 seconds to 5.

<device>system-view

System View: return to User View with Ctrl+Z.

[device] stp tc-protection threshold 5

stp timer forward-delay

Syntax

stp timer forward-delay centi-seconds

undo stp timer forward-delay

View

System view

Parameters

centi-seconds: Forward delay in centiseconds to be set. This argument ranges from 400 to 3,000.

Description

Use the stp timer forward-delay command to set the forward delay of the device.

Use the undo stp timer forward-delay command to restore the forward delay to the default value.

By default, the forward delay of the device is 1,500 centiseconds.

To prevent the occurrence of temporary loops, when a port changes its state from discarding to forwarding, it undergoes an intermediate state and waits for a specific period to synchronize with the state transition of the remote devices. This state transition period is determined by the forward delay configured on the root bridge.

The forward delay setting configured on a root bridge applies to all non-root bridges.

As for the configuration of the three time-related parameters (namely, the hello time, forward delay, and max age parameters), the following formulas must be met to prevent frequent network jitter.

2 x (forward delay – 1 second) >= max age

Max age >= 2 x (hello time + 1 second)

You are recommended to specify the network diameter of the switched network and the hello time by using the stp root primary or stp root secondary command. After that, the three proper time-related parameters are automatically calculated by MSTP.

Related commands: stp timer hello, stp timer max-age, and stp bridge-diameter.

Examples

# Set the forward delay to 2,000 centiseconds.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp timer forward-delay 2000

stp timer hello

Syntax

stp timer hello centi-seconds

undo stp timer hello

View

System view

Parameters

centi-seconds: Hello time to be set, in the range of 100 to 1,000 (in centiseconds).

Description

Use the stp timer hello command to set the hello time of the device.

Use the undo stp timer hello command to restore the hello time of the device to the default value.

By default, the hello time of the device is 200 centiseconds.

A root bridge regularly sends out configuration BPDUs to maintain the stability of existing spanning trees. If the device does not receive BPDU packets in a specified period, spanning trees will be recalculated because BPDU packets time out. When a device becomes a root bridge, it regularly sends BPDUs at the interval specified by the hello time you have configured on it. The other none-root-bridge devices adopt the interval specified by the hello time.

As for the configuration of the three time-related parameters (namely, the hello time, forward delay, and max age parameters), the following formulas must be met to prevent frequent network jitter.

2 × (forward delay – 1 second) >= max age

Max age >= 2 × (hello time + 1 second)

Related commands: stp timer forward-delay, stp timer max-age, and stp bridge-diameter.

Examples

# Set the hello time to 400 centiseconds.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp timer hello 400

stp timer max-age

Syntax

stp timer max-age centi-seconds

undo stp timer max-age

View

System view

Parameters

centi-seconds: Max age to be set, in the range of 600 to 4,000 (in centiseconds).

Description

Use the stp timer max-age command to set the max age of the device.

Use the undo stp timer max-age command to restore the default max age.

By default, the max age of a device is 2,000 centiseconds.

MSTP is capable of detecting link failures and automatically restoring redundant links to the forwarding state. In CIST, devices use the max age parameter to judge whether or not a received configuration BPDU times out. Spanning trees will be recalculated if a configuration BPDU received by a port times out.

The max age is meaningless to MSTIs. The max age configured for the root bridge of the CIST applies to all devices operating on the CIST, including the root bridge.

As for the configuration of the three time-related parameters (namely, the hello time, forward delay, and max age parameters), the following formulas must be met to prevent frequent network jitter:

2 × (forward delay – 1 second) >= max age,

Max age >= 2 × (hello time + 1 second).

You are recommended to specify the network diameter of the switched network and the hello time parameter by using the stp root primary or stp root secondary command. After that, the three proper time-related parameters are automatically determined by MSTP.

Related commands: stp timer forward-delay, stp timer hello, and stp bridge-diameter.

Examples

# Set the max age to 1,000 centiseconds.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp timer max-age 1000

stp timer-factor

Syntax

stp timer-factor number

undo stp timer-factor

View

System view

Parameters

number: Hello time factor to be set, in the range of 1 to 10.

Description

Use the stp timer-factor command to set the timeout time of a device in the form of a multiple of the hello time.

Use the undo stp timer-factor command to restore the hello time factor to the default value.

By default, the hello time factor of the device is 3.

A device regularly sends protocol packets to its neighboring devices at the interval specified by the hello time parameter to test the links. Generally, a device regards its upstream device faulty if the former does receive any protocol packets from the latter in a period three times of the hello time and then initiates the spanning tree recalculation process.

Spanning trees may be recalculated even in a steady network if an upstream device is always busy. You can configure the hello time factor to a larger number to avoid this problem. Normally, the timeout time can be four (or more) times of the hello time. For a steady network, the timeout time can be five to seven times of the hello time.

Examples

# Set the hello time factor to 7.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp timer-factor 7

stp transmit-limit

Syntax

stp transmit-limit packetnum

undo stp transmit-limit

View

Ethernet port view

Parameters

packetnum: Maximum number of configuration BPDUs a port can transmit in each hello time. This argument ranges from 1 to 255.

Description

Use the stp transmit-limit command to set the maximum number of configuration BPDUs the current port can transmit in each hello time.

Use the undo stp transmit-limit command to restore the maximum number to the default value.

By default, the maximum number of configuration BPDUs a port can transmit in each hello time is 10.

A larger number configured by the stp transmit-limit command allows more configuration BPDUs to be transmitted in each hello time, which may occupy more resources on the device. So you are recommended configure it to a proper value to avoid network topology jitter and prevent MSTP from occupying too many bandwidth resources.

Related commands: stp interface transmit-limit.

Examples

# Set the maximum number of configuration BPDUs that can be transmitted through GigabitEthernet 1/0/1 in each hello time to 15.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] interface GigabitEthernet1/0/1

[device-GigabitEthernet1/0/1] stp transmit-limit 15

vlan-mapping modulo

Syntax

vlan-mapping modulo modulo

View

MST region view

Parameters

modulo: Modulo by which VLANs are mapped to spanning tree instances, in the range of 1 to 16.

Description

Use the vlan-mapping modulo command to set the modulo by which VLANs are mapped to spanning tree instances.

By default, all VLANs in a network are mapped to the CIST (spanning tree instance 0).

MSTP uses a VLAN mapping table to describe VLAN-to-MSTI mappings. You can use this command to establish the VLAN mapping table and map VLANs to spanning tree instances in a specific way.

Note that a VLAN cannot be mapped to multiple different spanning tree instances at the same time. A VLAN-to-MSTI mapping becomes invalid when you map the VLAN to another spanning tree instance.

You can map VLANs to the specific spanning tree instances rapidly by using the vlan-mapping modulo modulo command. The ID of the spanning tree instance to which a VLAN is mapped can be figured out by using the following formula:

(VLAN ID-1) % modulo + 1.

In this formula, (VLAN ID-1) % modulo yields the module of (VLAN ID-1) with regards to the modulo argument. For example, if you set the modulo argument to 16, then VLAN 1 is mapped to spanning tree instance 1, VLAN 2 is mapped to spanning tree instance 2, …, VLAN 16 is mapped to spanning tree instance 16, VLAN 17 is mapped to spanning tree instance 1, and so on.

Related commands: check region-configuration, revision-level, region-name, and active region-configuration.

Examples

# Map VLANs to spanning tree instances, with the modulo being 16.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] stp region-configuration

[device-mst-region] vlan-mapping modulo 16

vlan-vpn tunnel

Syntax

vlan-vpn tunnel

undo vlan-vpn tunnel

View

System view

Parameters

None

Description

Use the vlan-vpn tunnel command to enable the VLAN-VPN tunnel function for a device.

Use the undo vlan-vpn tunnel command to disable the VLAN-VPN tunnel function.

The VLAN-VPN tunnel function enables BPDUs to be transparently transmitted between geographically dispersed user networks through specified VLAN VPNs in operator’s networks, through which spanning trees can be calculated across these user networks and are independent of those of the operator’s network.

By default, the VLAN-VPN tunnel function is disabled.

l The VLAN-VPN tunnel function can only be enabled on STP-enabled devices.

l To enable the VLAN-VPN tunnel function, make sure the links between operator’s networks are trunk links.

Examples

# Enable the VLAN-VPN tunnel function for the device.

<device> system-view

System View: return to User View with Ctrl+Z.

[device] vlan-vpn tunnel

H3C WX3000 Series Unified Switches Switching Engine Command Reference-6W103

instance

stp tc-protection threshold

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