Configuring MST region-related parameters (especially the VLAN mapping table) results in spanning trees being regenerated. To reduce network topology jitter caused by such configurations, MSTP (multiple spanning tree protocol) does not regenerate 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.

This command causes the switch to operate with the new MST region-related settings you configured and spanning trees to be regenerated.

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

Example

# Activate the MST region-related settings manually.

<H3C> system-view

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

[H3C] stp region-configuration

[H3C-mst-region] active region-configuration

1.1.2 check region-configuration

Syntax

check region-configuration

View

MST region view

Parameter

None

Description

Use the check region-configuration command to display the current MST region configuration information, including the region name, the revision level, and the VLAN mapping table.

In an MSTP region, make sure that the MST region-related settings (especially the VLAN mapping table) are right. MSTP-enabled switches are in the same region only when they have the same MST region-related settings. A switch cannot be in a respected region if any one of the above three MST region-related settings is not consistent with that of another switch in the region.

You can use this command to view inactivated MST region-related settings, according to which you can find out the MST region the switch currently belongs to or check to see whether or not the MST region-related configuration is correct.

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

Example

# Display the MST region configuration of the current switch.

<H3C> system-view

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

[H3C] stp region-configuration

[H3C-mst-region] check region-configuration

Admin Configuration

Format selector :0

Region name :00e0fc003900

Revision level :0

Instance Vlans Mapped

0 1 to 9, 11 to 4094

16 10

Table 1-1 Description on the fields of the check region-configuration command

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

1.1.3 display stp

Syntax

display stp [ instance instance-id ] [ interface interface-list | slot slot-number ] [ brief ]

View

Any view

Parameter

instance-id: ID of the MSTI, ranging from 0 to 16. A value of 0 specifies 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, the STP-related information about which is to be displayed.

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

Description

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

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 MSTI nor port list is specified, the command displays spanning tree information about all MSTIs on all ports in the order of port numbers.

l If only one MSTI is specified, the command displays information about the specified MSTI on all ports in the order of the port numbers.

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

l If both an MSTI and a port list are specified, the command displays spanning tree information about the specified MSTI and the specified ports in the order of MSTI IDs.

MSTP state information includes:

l Global CIST parameters: Protocol operation mode, switch priority in the CIST instance, MAC address, Hello time, Max age, Forward delay, Max hops, the CIST root, the external path cost from the switch to the CIST root, region root, the internal path cost from the switch to the region root, CIST root port of the switch, the state of the BPDU (bridge protocol data unit) guard function (enabled or disabled), and the state of the digest snooping function (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 the port is a point-to-point link, the maximum transmitting speed, type of the enabled guard function, state of the digest snooping function (enabled or disabled), VLAN mappings, Hello time, Max age, Forward delay, Message-age time, and Remaining-hops.

l Global MSTI parameters: MSTI ID, bridge priority of the MSTI, 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 command: reset stp.

Example

# Display the state and statistical information about an MSTI.

<H3C> display stp instance 0 interface Ethernet 1/0/1 to Ethernet 1/0/4 brief

MSTID Port Role STP State Protection

0 Ethernet1/0/1 ALTE DISCARDING LOOP

0 Ethernet1/0/2 DESI FORWARDING NONE

0 Ethernet1/0/3 DESI FORWARDING NONE

0 Ethernet1/0/4 DESI FORWARDING NONE

Table 1-2 Description on the fields of the display stp command

Field	Description
MSTID	ID of an MSTI in the MST region
Port	Port number corresponding to the specified MSTI
Role	Port role
STP State	STP state on the port, which can be forwarding and discarding.
Protection	Guard type of the port

1.1.4 display stp region-configuration

Syntax

display stp region-configuration

View

Any view

Parameter

None

Description

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

Related command: stp region-configuration.

Example

# Display the activated MST region configuration.

<H3C> 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 1-3 Description on the fields of the display stp region-configuration command

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

1.1.5 instance

Syntax

instance instance-id vlan vlan-list

undo instance instance-id [ vlan vlan-list ]

View

MST region view

Parameter

instance-id: ID of an MSTI, ranging from 0 to 16. A value of 0 specifies 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 switch supports this kind of VLAN IDs), such as VLAN 4095, VLAN 4096, can only be mapped to the CIST (instance 0).

Description

Use the instance command to map specified VLANs to a specified MSTI.

Use the undo instance command to remove the mappings from the specified VLANs to the specified MSTI and remap the specified VLANs to the CIST (instance 0). If you specify no VLAN in the undo instance command, all VLANs mapped to the specified MSTI 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 switch. 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 MSTI by using these two commands.

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

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

Example

# Map VLAN 2 to MSTI 1.

<H3C> system-view

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

[H3C] stp region-configuration

[H3C-mst-region] instance 1 vlan 2

1.1.6 region-name

Syntax

region-name name

undo region-name

View

MST region view

Parameter

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

Description

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

Use the undo region-name command to revert to the default MST region name.

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

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

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

Example

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

<H3C> system-view

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

[H3C] stp region-configuration

[H3C-mst-region] region-name hello

1.1.7 reset stp

Syntax

reset stp [ interface interface-list ]

View

User view

Parameter

Description

Use the reset stp command to clear spanning tree-related statistics on Ethernet ports.

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

This command clears the spanning tree-related 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-related statistics on all ports.

Related command: display stp.

Example

# Clear the spanning tree-related statistics on Ethernet1/0/1 through Ethernet1/0/3.

<H3C> reset stp interface Ethernet 1/0/1 to Ethernet 1/0/3

1.1.8 revision-level

Syntax

revision-level level

undo revision-level

View

MST region view

Parameter

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

Description

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

Use the undo revision-level command to revert to the default revision level.

By default, the MSTP revision level is 0.

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

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

Example

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

<H3C> system-view

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

[H3C] stp region-configuration

[H3C-mst-region] revision-level 5

1.1.9 stp

Syntax

stp { enable | disable }

undo stp

View

System view, Ethernet port view

Parameter

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 revert to the default MSTP state globally or on a port.

By default, MSTP is disabled globally and on a port.

By default, once MSTP is enabled globally, it is enabled on a port.

After MSTP is enabled, the actual operation mode, which can be STP-compatible mode, RSTP-compatible mode, or MSTP mode, is determined by the protocol mode configured by users. A switch 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 command: stp mode, and stp interface.

Example

# Enable MSTP globally.

<H3C> system-view

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

[H3C] stp enable

# Disable MSTP on Ethernet1/0/1.

<H3C> system-view

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

[H3C] interface ethernet 1/0/1

[H3C-Ethernet1/0/1] stp disable

1.1.10 stp bpdu-protection

Syntax

stp bpdu-protection

undo stp bpdu-protection

View

System view

Parameter

None

Description

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

Use the undo stp bpdu-protection command to revert 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 directly connect to terminals (such as PCs) or file servers. These ports are usually configured as edge ports to achieve rapid transition. But they resume non-edge ports automatically upon receiving configuration BPDUs, which causes spanning tree regeneration 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 this type of attacks by utilizing the BPDU guard function. With this function enabled on a switch, the switch shuts down the edge ports that receive configuration BPDUs and then reports these cases to the administrator. If a port is shut down, only the administrator can restore it.

Example

# Enable the BPDU guard function.

<H3C> system-view

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

[H3C] stp bpdu-protection

1.1.11 stp bridge-diameter

Syntax

stp bridge-diameter bridgenum

undo stp bridge-diameter

View

System view

Parameter

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 switches between any two terminals in a switched network.

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

By default, the maximum number of switches between any two terminal devices in the switched network is 7.

The network diameter parameter is represented by the maximum number of switches between two communication ends.

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 7 (the default), the three time-relate settings, Hello time, Forward delay, and Max age, are set to their defaults as well.

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

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

Example

# Set the network diameter to 5.

<H3C> system-view

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

[H3C] stp bridge-diameter 5

1.1.12 stp config-digest-snooping

Syntax

stp config-digest-snooping

undo stp config-digest-snooping

View

System view

Parameter

None

Description

Use the stp config-digest-snooping command to enable the digest snooping function.

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

The digest snooping function is disabled by default.

According to IEEE 802.1s, two connected switches can interwork with each other through MSTIs in an MST region only when the two switches have the same MST region-related configuration. With MSTP employed, interconnected switches 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 some other vendors' switches adopt proprietary spanning tree protocols, they cannot interwork with other switches in an MST region even if they are configured with the same MST region-related settings as other switches in the MST region.

This kind of problems can be overcome by implementing the digest snooping function. If a switch port is connected to another vendor's switch that has the same MST region-related settings but adopts a proprietary spanning tree protocol, you can enable digest snooping on the port. Then the switch regards the peer switch connected to the port as in the same region and records the configuration digests carried in the BPDUs received from the switch, which will be put in the BPDUs to be sent to the peer switch. In this way, the switch can interwork with other vendors’ switches in an MST region.

& Note:

l The digest snooping function is needed only when your S7500 switch is connected to other vendors’ proprietary spanning tree protocol-adopted switches.

l To enable the digest snooping function successfully, you must first enable it on all the switch ports that connect to other vendors’ proprietary spanning tree protocol-adopted switches and then enable it globally.

l To enable the digest snooping function, the interconnected switches must be configured with exactly the same MST region settings.

l The digest snooping function must be enabled on all the switch ports that connect to other vendors' proprietary spanning tree protocol-adopted switches in the same MST region.

l With the digest snooping function enabled, the VLAN-to-MSTI mapping cannot be modified.

l The digest snooping function is not applicable to ports on the boundary of an MST region.

l The digest snooping function is not applicable to edge ports.

Example

# Enable the digest snooping function for Ethernet1/0/1.

<H3C> system-view

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

[H3C] interface Ethernet1/0/1

[H3C-Ethernet1/0/1] stp config-digest-snooping

[H3C-Ethernet1/0/1] quit

[H3C]stp config-digest-snooping

1.1.13 stp cost

Syntax

stp [ instance instance-id ] cost cost

undo stp [ instance instance-id ] cost

View

Ethernet port view

Parameter

instance-id: ID of an MSTI, ranging from 0 to 16. A value of 0 specifies 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 MSTI.

Use the undo stp cost command to revert to the default path cost of the current port in the specified MSTI.

By default, a switch automatically calculates the path costs of a port in different MSTIs 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 on CIST.

The path costs of a port in MSTIs affect the roles of the ports in the MSTIs. 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 an MSTI may change the role of the port in the instance and put it in state transition.

Related command: stp interface cost.

Example

# Set the path cost of Ethernet1/0/3 in MSTI 2 to 200.

<H3C> system-view

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

[H3C] interface ethernet1/0/3

[H3C-Ethernet1/0/3] stp instance 2 cost 200

1.1.14 stp edged-port

Syntax

stp edged-port { enable | disable }

undo stp edged-port

View

Ethernet port view

Parameter

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 switch are non-edge ports.

An edge port is a port that is directly connected to a user terminal instead of another switch or a network segment. Rapid transition is applied to edge ports because, on these ports, no loops can be incurred by network topology changes. You can enable a port to transit 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 transit to the forwarding state rapidly.

Normally, configuration BPDUs cannot reach an edge port because the port is not connected to another switch. 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 command: stp interface edged-port.

Caution:

Among loop guard function, root guard function and edge port setting, only one can be valid on a port at one time.

Example

# Configure Ethernet1/0/1 as a non-edge port.

<H3C> system-view

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

[H3C] interface ethernet1/0/1

[H3C-Ethernet1/0/1] stp edged-port disable

1.1.15 stp interface

Syntax

stp interface interface-list { enable | disable }

View

System view

Parameter

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 switch if MSTP is globally enabled on the switch, and is disabled on the ports if MSTP is globally disabled.

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

Caution:

Disabling MSTP on ports may result in loops.

Related command: stp mode, stp.

Example

# Enable MSTP on Ethernet1/0/1 in system view.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/1 enable

1.1.16 stp interface config-digest-snooping

Syntax

stp interface interface-list config-digest-snooping

undo stp interface interface-list config-digest-snooping

View

System view

Parameter

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.

Description

Use the stp interface config-digest-snooping command to enable the digest snooping function.

Use the undo stp interface config-digest-snooping command to disable the digest snooping function.

By default, the digest snooping function is disabled.

According to IEEE 802.1s, two interconnected MSTP switches can interwork with each other through MSTIs in an MST region only when the two switches have the same MST region-related configuration. Interconnected MSTP switches 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.)

This problem can be overcome by implementing the digest snooping function. If a port on an S7500 switch is connected to another vendor's switch that has the same MST region-related settings as its own but adopts a proprietary spanning tree protocol, you can enable digest snooping on the port. Then the S7500 switch regards the switch of another vendor as in the same region; it records the configuration digests carried in the BPDUs received from the switch of another vendor, and put them in the BPDUs to be sent to the switch of another vendor. In this way, the S7500 switches can interwork with other vendors' switches in the same MST region.

& Note:

l The digest snooping function is needed only when your S7500 switch is connected to other vendors’ proprietary protocol-adopted switches.

l To enable the digest snooping function successfully, you must first enable it on all the ports of your S7500 switch that are connected to other vendors’ proprietary protocol-adopted switches and then enable it globally.

l To enable the digest snooping function, the interconnected switches must be configured with exactly the same MST region-related configuration.

l The digest snooping function must be enabled on all the ports of your S7500 switch that are connected to other vendors' proprietary protocol-adopted switches in the same MST region.

l With the digest snooping function enabled, the VLAN-to-MSTI mapping cannot be modified.

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

l The digest snooping function is not applicable to edge ports.

Example

# Enable the digest snooping function on Ethernet1/0/1 in system view.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/1 config-digest-snooping

1.1.17 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

Parameter

instance-id: MSTI ID ranging from 0 to 16. A value of 0 specifies the CIST.

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

Description

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

Use the undo stp interface cost command to revert to the default path cost(s) of the specified port(s) in the specified MSTI in system view.

By default, a switch automatically calculates the path costs of a port in different MSTIs 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 differs with port speed. Refer to Table 1-4 for details.

Related command: stp cost.

Example

# Set the path cost of Ethernet1/0/3 in MSTI 2 to 400 in system view.

<H3C> system-view

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

[H3C] stp instance 2 interface Ethernet 1/0/3 cost 400

1.1.18 stp interface edged-port

Syntax

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

undo stp interface interface-list edged-port

View

System view

Parameter

enable: Configures the specified Ethernet ports to be edge ports.

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

Description

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

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

Use the undo stp interface edged-port command to restore the specified Ethernet port(s) to their default states.

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

Related command: stp edged-port.

Caution:

Among loop guard function, root guard function and edge port setting, only one can be valid on a port at one time.

Example

# Configure Ethernet1/0/3 as an edge port in system view.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/3 edged-port enable

1.1.19 stp interface loop-protection

Syntax

stp interface interface-list loop-protection

undo stp interface interface-list loop-protection

View

System view

Parameter

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 revert to the default state of the loop guard function in system view.

The loop guard function is disabled by default.

Related command: stp loop-protection.

Caution:

Among loop guard function, root guard function and edge port setting, only one can be valid on the same port.

Example

# Enable the loop guard function on Ethernet1/0/1.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/1 loop-protection

1.1.20 stp interface mcheck

Syntax

stp [ interface interface-list ] mcheck

View

System view

Parameter

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

Related command: stp mcheck, and stp mode.

Example

# Perform the mCheck operation for Ethernet1/0/3 in system view.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/3 mcheck

1.1.21 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

Parameter

interface-type: Port type.

interface-number: Port number.

Description

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

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

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

Some other vendors' switches adopt proprietary spanning tree protocols that are similar to RSTP in the way to implement rapid transition on designated ports. When a switch of this kind operates as the upstream switch of an S7500 switch running MSTP, the upstream designated port fails to change their states rapidly.

The rapid transition function is developed to avoid this case. When an S7500 switch running MSTP is connected in the upstream direction to another vendor's switch running proprietary spanning tree protocol, you can enable the rapid transition function on the ports of the S7500 switch operating as the downstream switch. Among these ports, 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 switch. This enables designated ports of the upstream switch to change their states rapidly.

Related command: stp no-agreement-check.

& Note:

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

l If you configure the rapid transition function on the designated port, the function does not take effect on the port.

Example

# Enable the rapid transition function for Ethernet1/0/1.

<H3C> system-view

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

[H3C]stp interface Ethernet1/0/1 no-agreement-check

1.1.22 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

Parameter

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 function is not applicable to ports on non-point-to-point links.

If an Ethernet port is the master port of an aggregated port 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 only 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 MSTIs (that is, the port is configured to connect to a point-to-point link (or a non-point-to-point link) in all MSTIs). 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 command: stp point-to-point.

Example

# Configure the link connected to Ethernet1/0/3 as a point-to-point link in system view.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/3 point-to-point force-true

1.1.23 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

Parameter

instance-id: MSTI ID ranging from 0 to 16. A value of 0 specifies 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, and 32). The default port priority of a port in any MSTI is 128.

Description

Use the stp interface port priority command to set a port priority for the specified ports in the specified MSTI.

Use the undo stp interface port priority command to restore the specified ports to the default port priority in the specified MSTI.

If you specify the instance-id argument to be 0, these two commands apply to the port priorities on the CIST. The role a port plays in an MSTI is determined by the port priority in the MSTI. A port on an MSTP-enabled switch 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 achieve load balancing by VLANs. Changing port priorities results in port roles being re-determined and may cause state transitions.

Related command: stp port priority.

Example

# Set the port priority of Ethernet1/0/3 to 16 in MSTI 2.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/3 instance 2 port priority 16

1.1.24 stp interface root-protection

Syntax

stp interface interface-list root-protection

undo stp interface interface-list root-protection

View

System view

Parameter

Description

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

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

By default, the root guard function is disabled.

Configuration errors or attacks may result in configuration BPDUs with their 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 travel along high-speed links may be led to low-speed links, and network congestion may occur.

You can avoid this by utilizing the root guard function. Ports with this function enabled can only be kept as designated ports in all MSTIs. When a port of this type receives configuration BPDUs with higher priorities, it changes to discarding state (rather than becomes 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 command: stp root-protection.

Caution:

Among loop guard function, root guard function and edge port setting, only one can be valid on a port at one time.

Example

# Enable the root guard function on Ethernet1/0/1.

<H3C> system-view

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

[H3C] stp interface Ethernet 1/0/1 root-protection

1.1.25 stp interface transmit-limit

Syntax

stp interface interface-list transmit-limit packetnum

undo stp interface interface-list transmit-limit

View

System view

Parameter

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 revert to the default maximum number.

The larger the packetnum argument is, the more packets a port can transmit in each Hello time. 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 network resources when network topology jitter occurs.

Related command: stp transmit-limit.

Example

# Set the maximum transmitting speed of Ethernet1/0/3 to 5.

<H3C> system-view

System View: return to User View with

Table of Contents

15-MSTP Command

1.1.11 stp bridge-diameter

1.1.12 stp config-digest-snooping