Commands For Mstp

Command: abort
Function: Abort the current MSTP region configuration, quit MSTP Region Mode, and return to Global Mode.
Parameters: None.
Command mode: MSTP Region Mode
Default: None.
Usage guide: This command quits MSTP Region Mode without saving the current configuration. The previous MSTP region configuration is preserved.
Example: Quit MSTP Region Mode without saving the current configuration.

active500EM(config-mstp-region)#abort
active500EM(config)#

 

Command: exit
Function: Save current MSTP region configuration, quit MSTP Region Mode, and return to Global Mode.
Parameters: None.
Command mode: MSTP Region Mode
Default: None.
Usage guide: This command quits MSTP Region Mode and saves the current configuration.
Example: Quit MSTP Region Mode and save the current configuration.

active500EM(config-mstp-region)#exit
active500EM(config)#

 

Command: instance <instance-id> vlan <vlan-list>
no instance <instance-id> [vlan <vlan-list>] Function: In MSTP Region Mode, create the instance and set the mappings between VLANs and instances. The no command removes the specified instance and the specified mappings between the VLANs and instances.
Parameters:

• <instance-id>: sets the instance number. The valid range is from 0 to 64.
• <vlan-list>: sets consecutive or non-consecutive VLAN numbers. ?-? refers to consecutive numbers, and ?;? refers to non-consecutive numbers.

Command mode: MSTP Region Mode
Default: 0 is the only instance. VLAN 1 to 4094 belong to the instance 0.
Usage guide: This command sets the mappings between VLANs and instances. If all mapping relationships and other attributes are the same, the switches are considered to be in the same MSTP region. Before setting any instances, all VLANs belong to the instance 0. MSTP can support a maximum of 64 MSTIs (except for CISTs). CIST can be treated as MSTI 0. All other instances are considered to be an instance of 1 to 64.
Example: Map VLAN1-10 and VLAN 100-110 to instance 1.

active500EM(config)#spanning-tree mst configuration
active500EM(config-mstp-region)#instance 1 vlan 1-10;100-110

 

Command: name <name>
no name
Function: Set MSTP region name. The no command restores to default.
Parameter:

• <name>: MSTP region name with a length limit of 32 characters.

Command mode: MSTP Region Mode
Default: MAC address of this bridge.
Usage guide: The bridges with the same MSTP region name and same attributes are considered to be in the same MSTP region.
Example: Set MSTP region name to mstp-test.

active500EM(config)#spanning-tree mst configuration
active500EM(config-mstp-region)#name mstp-test

 

Command: no <instance-id> | <name> | <revision-level>
Function: Cancel one command or set it to the initial value.
Parameters:

• <instance-id>: instance number.
• <name>: MSTP region name.
• <revision-level>: revision level of the MSTP configuration caption.

Command mode: MSTP Region Mode
Default: The default revision level is 0.
Usage guide: This command deletes the specified instance and MSTP region name.
Example: Delete instance 1.

active500EM(config-mstp-region)#no instance 1

 

Command: revision-level <level>
no revision-level
Function: In MSTP region mode, this command sets the revision level for MSTP configuration. The no command restores to default.
Parameters:

• <level>: revision level. The valid range is from 0 to 65535.

Command mode: MSTP Region Mode
Default: 0.
Usage guide: This command sets the revision level for MSTP configuration. The bridges with the same MSTP revision level and same attributes are considered to be in the same MSTP region.
Example: Set revision level to 2000.

active500EM(config)#spanning-tree mst configuration
active500EM(config-mstp-region)# revision-level 2000

 

Command: show
Function: Display the current system information.
Parameters: None.
Command mode: MSTP Region Mode
Default: None.
Usage guide: This command displays the current system information.
Example: Display the current system information.

active500EM(config-mstp-region)#show

 

Command: spanning-tree
no spanning-tree
Function: Enable MSTP in Global Mode and Port Mode. The no command disables MSTP.
Parameters: None.
Command mode: Global Mode and Port Mode
Default: MSTP is not enabled by default.
Usage guide: If MSTP is enabled in Global Mode, it is enabled for all ports except the ports which are explicitly set to MSTP disable.
Example: Enable MSTP in Global Mode and disable MSTP in the interface 1/0/2.

active500EM(config)#spanning-tree
active500EM(config)#interface ethernet 1/0/2
active500EM(config-if-ethernet1/0/2)#no spanning-tree

 

Command: spanning-tree cost <cost>
no spanning-tree cost
Function: Sets the path cost of the current port. The no command restores the default setting.
Parameter:

• <cost>: sets path cost. The valid range is from 1 to 200,000,000.

Command mode: Port Mode
Default: The port cost is relative to the port bandwidth:

For the aggregation ports, the default costs are as below:

Usage guide: By setting the port cost, users can control the cost from the current port to the root bridge in order to control the port elections and the instance designated port.
Example: On port 1/0/2, set the port cost to 3000000.

active500EM(config-if-ethernet1/0/2)#spanning-tree cost 3000000

 

Command: spanning-tree digest-snooping
no spanning-tree digest-snooping
Function: Configure the port to use the authentication string of the partner port. The no command restores the port-generated authentication string.
Parameters: None.
Command mode: Port Mode
Default: Don?t use the authentication string of the partner port.
Usage guide: According to MSTP protocol, the region authentication string is generated by the MD5 algorithm using the public authentication key, instance ID, and VLAN ID. Since some manufacturers don?t use a public authentication key, this causes incompatibility. After the command is executed, the port can use the uthentication string of a partner port and realize compatibility with other manufacturer’s equipment. Note: Because the authentication string is related to instance ID and VLAN ID, the command may recognize the equipment with a different instance and VLAN relation as being in the same region. Before the command is executed, make sure that instance and VLAN relation is established for all the equipment. If there are multiple pieces of equipment connected, all the connected ports should execute this command.
Example: Configure the authentication string of the partner port.

active500EM(config)#interface ethernet 1/0/2
active500EM(config-if-ethernet1/0/2)#spanning-tree digest-snooping
active500EM(config-if-ethernet1/0/2)#

 

Command: spanning-tree format {standard | privacy | auto}
no spanning-tree format
Function: Configure the format of the port packet to be interactive with products of other companies. The no command restores the default format.
Parameters:

• standard: indicates the packet format provided by IEEE.
• privacy: indicates the privacy packet format, which is compatible with Cisco equipment.
• auto: indicates the automatically identified packet format which is determined by checking the format of the received packets.

Command mode: Port Mode
Default: Auto Packet Format.
Usage guide: Since Cisco has adopted a packet format that is different than the one provided by IEEE, many companies also adopted the Cisco format to be Cisco-compatible. Both formats are supported. The standard format is the one provided by IEEE, and the privacy packet format is Cisco-compatible. In cases where the packet format is unknown, the AUTO configuration will be preferred to identify the format of the packets sent. The Auto packet format is set by default to ensure better compatibility with previous products and the leading companies. The packet format will be in privacy format before receiving the partner packet when configured to Auto. When the format is not Auto and the received packet format from the partner does not match the configured format, the state of the port which receives the unmatched packet is set to ?Discarding? to prevent both sides from considering themselves the root. When the Auto format is set, and multiple incompatible pieces of equipment are connected on the port (e.g. an equipment running through a Hub or Transparent Transmission BPDU is connected with several which are running MSTP), the format alter counts will be recorded and the port will be disabled at a certain count threshold. The port can only be re-enabled by the administrator.
Example: Configure port message format to IEEE message format. active500EM(config)#interface ethernet 1/0/2.

active500EM(config-if-ethernet1/0/2)#spanning-tree format standard
active500EM(config-if-ethernet1/0/2)#

 

Command: spanning-tree forward-time <time>
no spanning-tree forward-time
Function: Set the switch forward delay time. The no command restores to default.
Parameter:

• <time>: forward delay time in seconds. The valid range is from 4 to 30.

Command mode: Global Mode
Default: 15 seconds.
Usage guide: When the network topology changes, the status of the port is changed from blocking to forwarding. This delay is called the forward delay. The forward delay is a coordinate between hello time and maximum age. The parameters should meet the following conditions. Otherwise, the MSTP may work incorrectly.
2 * (Bridge-Forward-Delay – 1.0 seconds) >= Bridge-Max-Age
Bridge-Max-Age >= 2 * (Bridge-Hello-Time + 1.0 seconds)
Example: In global mode, set MSTP forward delay time to 20 seconds.

active500EM(config)#spanning-tree forward-time 20

 

Command: spanning-tree hello-time <time>
no spanning-tree hello-time
Function: Set hello-time on the switch. The no command restores to default.
Parameters:

• <time>: hello-time in seconds. The valid range is from 1 to 10.

Command mode: Global Mode
Default: 2 seconds.
Usage guide: Hello-time is the interval at which the switch sends BPDUs. Hello-time works congruently with forward delay and maximum age. The parameters should meet the following conditions. Otherwise, the MSTP may work incorrectly.
2 * (Bridge-Forward-Delay – 1.0 seconds) >= Bridge-Max-Age
Bridge-Max-Age >= 2 * (Bridge-Hello-Time + 1.0 seconds)
Example: Set MSTP hello-time to 5 seconds in Global Mode.

active500EM(config)#spanning-tree hello-time 5

 

Command: spanning-tree link-type p2p {auto | force-true | force-false}
no spanning-tree link-type
Function: Set the link type of the current port. The no command restores the link type to auto-negotiation.
Parameters:

• auto: sets auto-negotiation.
• force-true: forces the link to a type of point-to-point.
• force-false: forces the link to a type of non point-to-point.

Command mode: Port Mode
Default: The link type is auto by default. The MSTP detects the link type automatically.
Usage guide: When the port is full-duplex, MSTP sets the port link type as point-to-point. When the port is half-duplex, MSTP sets the port link type as shared.
Example: Force the port 1/0/7-8 to a type of point-to-point.

active500EM(config)#interface ethernet 1/0/7-8
active500EM(config-port-range)#spanning-tree link-type p2p force-true

 

Command: spanning-tree maxage <time>
no spanning-tree maxage
Function: Set the maximum aging time for BPDU. The no command restores to default.
Parameter:

• <time>: maximum aging time in seconds. The valid range is from 6 to 40.

Command mode: Global Mode
Default: 20 seconds.
Usage guide: The lifetime of BPDU is called maximum age time. The maximum age works congruently with hello time and forward delay. The parameters should meet the following conditions. Otherwise, MSTP may work incorrectly.
2 * (Bridge-Forward-Delay – 1.0 seconds) >= Bridge-Max-Age
Bridge-Max-Age >= 2 * (Bridge-Hello-Time + 1.0 seconds)
Example: In Global Mode, set max age time to 25 seconds.

active500EM(config)#spanning-tree maxage 25

 

Command: spanning-tree max-hop <hop-count>
no spanning-tree max-hop
Function: Set maximum MSTP BPDU hops. The no command restores the default setting.
Parameters:

• <hop-count>: sets maximum hops. The valid range is from 1 to 40.

Command mode: Global Mode
Default: The max hop is 20.
Usage guide: MSTP uses max-age to evaluate the lifetime of BPDU. In addition, MSTP uses max-hop to evaluate the lifetime of BPDU. BPDU has the max value when it initiates from the MSTI root bridge. Once the BPDU is received, the value of the max-hop is reduced by 1. When a port receives the BPDU with a max-hop of 0, it drops this BPDU and identifies itself as the designated port to send the BPDU.
Example: Set max hop to 32.

active500EM(config)#spanning-tree max-hop 32

 

Command: spanning-tree mcheck
Function: Force the port to run in MSTP Mode.
Parameters: None.
Command mode: Port Mode
Default: The port is in the MSTP mode.
Usage guide: If a network attached to the current port is running IEEE 802.1D STP, the port converts itself to run in STP mode. This command is used to force the port to run in MSTP Mode, but once the port receives STP messages, it changes to work in STP mode again. This command can only be used when the switch is running in IEEE802.1s MSTP mode.
Example: Force the port 1/0/2 to run in the MSTP mode.

active500EM(config-if-ethernet1/0/2)#spanning-tree mcheck

 

Command: spanning-tree mode {mstp | stp | rstp}
no spanning-tree mode
Function: Set the spanning-tree mode in the switch. The no command restores the default setting.
Parameters:

• mstp: sets the switch in IEEE802.1s MSTP mode.
• stp: sets the switch in IEEE802.1D STP mode.
• rstp: sets the switch in IEEE802.1D RSTP mode.

Command mode: Global Mode
Default: MSTP Mode.
Usage guide: When the switch is in IEEE802.1D STP mode, it only sends standard IEEE802.1D BPDU and TCN BPDU. It drops any MSTP BPDUs.
Example: Set the switch to STP mode.

active500EM(config)#spanning-tree mode stp

 

Command: spanning-tree mst configuration
no spanning-tree mst configuration
Function: Enter MSTP Mode. Under MSTP Mode, the MSTP attributes can be set. The no command restores the attributes of the MSTP to their default values.
Parameters: None.
Command mode: Global Mode
Default: The default values of the attributes of the MSTP region are listed as below:
Table 14-1: Default values of the attributes of the MSTP region.

Usage guide: Whether the switch is in the MSTP Region Mode or not, users can enter the MSTP Mode, configure the attributes, and save the configuration. When the switch is running in MSTP Mode, the system will generate the MST configuration identifier according to the MSTP configuration. If the switches have the same MST configuration identifier, then they are considered as being in the same MSTP region.
Example: Enter MSTP Region Mode.

active500EM(config)#spanning-tree mst configuration
active500EM(config-mstp-region)#

 

Command: spanning-tree mst <instance-id> cost <cost>
no spanning-tree mst <instance-id> cost
Function: Sets the path cost of the current port in the specified instance. The no command restores to default.
Parameters:

• <instance-id>: sets the instance ID. The valid range is 0 to 64.
• <cost>: sets the path cost. The different cost formats have different ranges. For the default dot1t mode, the valid range is 1 to 200000000, and the valid range for dot1d is 1 to 65535.

Command mode: Port Mode
Default: By default, the port cost is relevant to port bandwidth:

For the aggregation ports, the default costs are as below:

Port cost relevant to port type and speed:

Usage guide: By setting the port cost, users can control the cost from the current port to the root bridge in order to control the elections of root port and the designated port of the instance.
Example: On the port1/0/2, set the MSTP port cost in the instance 2 to 3000000.

active500EM(config-if-ethernet1/0/2)#spanning-tree mst 2 cost 3000000

 

Command: spanning-tree cost-format {dot1d | dot1t}
Function: In Global Mode, users can select the path-cost format with dot1d or dot1t.
Parameters: None.
Command mode: Global Mode
Default: dot1t format.
Usage guide: There are two formats for cost value: they are dot1d, marked on IEEE802.1d-2008, and dot1t, marked on IEEE802.1t, however, the path-cost ranges are different. The dot1d range is from 1 to 65535, and the dot1t range is from 1 to 200000000. If users have already configured the cost value of the link with the spanning-tree cost command manually, changing the path-cost format with the cost-format command is successful only after the previous configuration is cleared.
Example: Set the cost format.

active500EM(config)#spanning-tree cost-format dot1d

 

Command: spanning-tree [mst <instance-id>] loopguard
no spanning-tree [mst <instance-id>] loopguard
Function: Enable the loopguard function for a specified instance. The no command disables the function.
Parameters:

• <instance-id>: MSTP instance ID.

Command mode: Port Mode
Default: Disable the loopguard function.
Usage guide: The command can protect a root port or alternate port from being changed as the designated port due to an invalid unilateralism link. When the receiving timer is met, the configured port with loopguard is set to block state.
Example: Configure port 1/0/2 in loopguard mode for instance 0.

active500EM(config)#interface ethernet 1/0/2
active500EM(config-if-ethernet1/0/2)#spanning-tree mst 0 loopguard

 

Command: spanning-tree mst <instance-id> port-priority <port-priority>
no spanning-tree mst <instance-id> port-priority
Function: Set the current port priority for the specified instance. The no command restores to default.
Parameters:

• <instance-id>: instance ID. The valid range is from 0 to 64.
• <port-priority>: port priority. The valid range is from 0 to 240. The values should be the multiples of 16, such as 0, 16, 32?240.

Command mode: Port Mode
Default: 128.
Usage guide: By setting the port priority, users can control the port ID of the instance in order to control the root port and designated port of the instance. The lower the value of the port priority, the higher the priority is.
Example: Set the port priority as 32 on the port 1/0/2 for the instance 1.

active500EM(config)#interface ethernet 1/0/2
active500EM(config-if-ethernet1/0/2)#spanning-tree mst 1 port-priority 32

 

Command: spanning-tree mst <instance-id> priority <bridge-priority>
no spanning-tree mst <instance-id> priority
Function: Set the bridge priority for the specified instance. The no command restores to default.
Parameters:

• <instance-id>: instance ID. The valid range is from 0 to 64.
• <bridge-priority>: switch priority. The valid range is from 0 to 61440. The values should be the multiples of 4096, such as 0, 4096, 8192?61440.

Command mode: Global Mode
Default: 32768.
Usage guide: By setting the bridge priority, users can change the bridge ID for the specified instance. The bridge ID can influence the elections of root bridge and designated port for the specified instance.
Example: Set the priority for Instance 2 to 4096.

active500EM(config)#spanning-tree mst 2 priority 4096

 

Command: spanning-tree [mst <instance-id>] rootguard
no spanning-tree [mst <instance-id>] rootguard
Function: Enable the rootguard function for a specified instance. The rootguard function forbids the port to become an MSTP root port. The no command disables the rootguard function.
Parameters:

• <instance-id>: MSTP instance ID.

Command mode: Port Mode
Default: Disable the rootguard function.
Usage guide: If the port is configured to be a rootguard port, it cannot be a MSTP root port. If a superior BPDU packet is received from a rootguard port, MSTP will not recalculate spanning-tree, and the status of the port will be set to root-inconsistent (blocked). If no superior BPDU packet is received from a blocked rootguard port, the port status will restore to forwarding. The rootguard function can maintain a relatively stable spanning-tree topology when a new switch is added to the network.
Example: Enable the rootguard function for port 1/0/2 in instance 0.

active500EM(config)#interface ethernet 1/0/2
active500EM(config-if-ethernet1/0/2)#spanning-tree mst 0 rootguard

 

Command: spanning-tree portfast [bpdufilter | bpduguard] [recovery <30-3600>] no spanning-tree portfast
Function: Set the current port as a boundary port with a BPDU filter and?BPDU guard as the specified or default mode. The no command sets the current port as a non-boundary port.
Parameters:

• bpdufilter: configures the border port mode as BPDU filter.
• bpduguard: configures the border port mode as BPDU guard.
• recovery: configures the border port to recover automatically after implementing a bpduguard violation operation.
• <30-3600>: recovery time. By default, automatic recovery is disabled.

Command mode: Port Mode
Default: All the ports are non-boundary ports by default when enabling MSTP.
Usage guide: When a port is set to be a boundary port, the port converts its status from discarding to forwarding without forward delay. Once the boundary port receives the BPDU, the port becomes a non-boundary port.
Example: Configure the border port mode as BPDU guard. Set the recovery time to 60s.

active500EM(config)#interface ethernet 1/0/2
active500EM(config-if-ethernet1/0/2)#spanning-tree portfast bpduguard recovery 60

 

Command: spanning-tree port-priority <port-priority>
no spanning-tree port-priority
Function: Set the port priority. The no command restores the default setting.
Parameters:

• <port-priority>: sets port priority. The valid range is from 0 to 240. The value should be the multiples of 16 (such as 0, 16, 32, 48?240).

Command mode: Port Mode
Default: The default port priority is 32768.
Usage guide: Sets the port priority for a designated port. Higher priority is given to those ports that have a smaller value for port priority.
Example: Set the port priority to 4096 on port 1.

active500EM(config-if-ethernet1/0/1)#spanning-tree port-priority 4096

 

Command: spanning-tree priority <bridge-priority>
no spanning-tree priority
Function: Configure the spanning-tree priority. The no command restores the default priority.
Parameter:

• <bridge-priority>: the priority of the bridging switch. Its value should be multiples of 4096 between 0 and 61440 (such as 0, 4096, 8192? 61440).

Command mode: Global Mode
Default: Priority is 32768.
Usage guide: The bridge ID can be altered by changing the priority of the switch. The priority information can also be used for priority of the root bridge and the specified ports. The bridge priority value of the switch is smaller, however the priority is higher.
Example: Configure the priority to 4096.

active500EM(config)#spanning-tree priority 4096

 

Command: spanning-tree rootguard
no spanning-tree rootguard
Function: Set the port as a root port. The no command sets the port as a non-root port.
Parameters: None.
Command mode: Port Mode
Default: The port is a non-root port.
Usage guide: If the port is configured to be a rootguard port, it cannot be a MSTP root port. If a superior BPDU packet is received from a rootguard port, MSTP does not recalculate spanning-tree and sets the status of the port to be root-inconsistent (blocked). If no superior BPDU packet is received from a blocked rootguard port, the port status will restore to forwarding. The rootguard function can maintain a relatively stable spanning-tree topology when a new switch is added to the network.
Example: Set the port 1 as a root port.

active500EM(config-if-ethernet1/0/1)#spanning-tree rootguard

 

Command: spanning-tree tcflush {enable| disable| protect}
no spanning-tree tcflush
Function: Configure the spanning-tree flush mode once the topology changes. The no command restores to default.
Parameters:

• enable: indicates that spanning-tree will flush once the topology changes.
• disable: indicates that spanning tree won?t flush when the topology changes.
• protect: indicates that spanning-tree will not flush more than once every 10 seconds.

Command mode: Global Mode
Default: Enabled.
Usage guide: According to MSTP, when topology changes, the port that sends the change message clears the MAC/ARP table. It is not necessary for some network environments to flush with every topology change. Note: For complicated networks, especially those which need to switch from one spanning tree branch to another rapidly, the disable mode is not recommended.
Example: Configure the spanning-tree flush mode once the topology changes are not flush to TC.

active500EM(config)#spanning-tree tcflush disable

 

Command: spanning-tree tcflush {enable| disable| protect}
no spanning-tree tcflush
Function: Configure the spanning-tree flush mode for a port once the topology changes. The no command restores to default.
Parameters:

• enable: indicates that spanning-tree will flush once the topology changes.
• disable: indicates that spanning tree won?t flush when the topology changes.
• protect: indicates that spanning-tree will not flush more than once every 10 seconds.

Command mode: Port Mode
Default: Global Configuration.
Usage guide: According to MSTP, when topology changes, the port that sends the change message clears the MAC/ARP table. It is not necessary for some network environments to flush with every topology change. Note: For complicated networks, especially those which need to switch from one spanning tree branch to another rapidly, the disable mode is not recommended.
Example: Configure the spanning-tree flush mode once the topology change is not flush to TC.

active500EM(config)#interface ethernet 1/0/2
active500EM(config-if-ethernet1/0/2)#spanning-tree tcflush disable

 

Command: spanning-tree transmit-hold-count <tx-hold-count-value>
no spanning-tree transmit-hold-count
Function: Set the maximum transmit-hold-count of port. The no command restores to default.
Parameters:

• <tx-hold-count-value>: The valid range is from 1 to 20.

Command mode: Global Mode
Default: 10.
Usage guide: Set the maximum number for sending BPDU within the hello time interval to control BPDU flow. The variable is applied to the entire MST bridge.
Example: Set the max transmit-hold-count as 20.

active500EM(config)#spanning-tree transmit-hold-count 20

 

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