To display VLAN information, use the show vlan command in privileged EXEC mode. Show
show vlan [brief | id vlan-id | name name [ifindex] | ifindex] Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesEach Ethernet switch port and Ethernet repeater group belong to only one VLAN. Trunk ports can be on multiple VLANs. If you shut down a VLAN using the state suspend or the state active command, these values appear in the Status field: •suspended—VLAN is suspended. •active—VLAN is active. If you shut down a VLAN using the shutdown command, these values appear in the Status field: •act/lshut—VLAN status is active but shut down locally. •sus/lshut—VLAN status is suspended but shut down locally. This is an example of the ouput for a VLAN (VLAN0002) that is active but shut down locally: If a VLAN is shut down internally, these values appear in the Status field: •act/ishut—VLAN status is active but shut down internally. •sus/ishut—VLAN status is suspended but shut down internally. This is an example of the ouput for a VLAN (VLAN0002) that is active but shut down internally: If a VLAN is shut down locally and internally, the value that is displayed in the Status field is act/ishut or sus/ishut. If a VLAN is shut down locally only, the value that is displayed in the Status field is act/lshut or sus/lshut. Separate VLAN ranges with a hyphen, and separate VLANs with a comma and no spaces in between. For example, you can enter the following: ExamplesThis example shows how to display the VLAN parameters for all VLANs within the administrative domain: This example shows how to display the VLAN name, status, and associated ports only: This example shows how to display the VLAN parameters for multiple VLANs: This example shows how to display the ifIndex number for VLAN 10 only: Table 31 describes the fields that are shown in the example.
Related Commands
show vlan access-log configTo display VLAN access control list (VACL) logging configuration properties, use the show vlan access-log config command in privileged EXEC mode. show vlan access-log config Syntax DescriptionThis command has no arguments or keywords. Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesSyslog messages are generated when the device reaches the set threshold, or five minutes after the previous message is displayed, whichever occurs first. The threshold controls the rate of the syslog message only and does not affect the log table entries. Packets exceeding the specified rate limit will not be logged. ExamplesThe following example shows how to display the configured VACL logging properties. The fields are self-explanatory. Related Commands
show vlan access-log flowTo display VLAN access control list (VACL) flow table contents, use the show vlan access-log flow command in privileged EXEC mode. show vlan access-log flow protocol {src-addr src-mask | any | host {hostname | host-ip}} {dst-addr dst-mask | any | host {hostname | host-ip}} [vlan vlan-id] Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesEntries for the standard protocols or any protocol can be displayed by specifying the protocol name or protocol number. Entries are removed from the table, if there is no increment in the packet counter after the last syslog message. ExamplesThe following example shows how to display the VACL flow table contents. Table 32 describes the significant fields shown in the display.
Related Commands
show vlan access-log statisticsTo display VLAN access control list (VACL) packet counts, messages, and other statistics, use the show vlan access-log statistics command in privileged EXEC mode. show vlan access-log statistics Syntax DescriptionThis command has no arguments or keywords. Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesAll platforms do not display VACL logging index. Packets that are dropped do not generate any syslog messages. ExamplesThe following example shows how to display the VACL statistics. The fields are self-explanatory. Related Commands
show vlan access-mapTo display the contents of a VLAN-access map, use the show vlan access-map command in privileged EXEC mode. show vlan access-map [map-name] Syntax Description
Command ModesPrivileged EXEC (#) Command History
ExamplesThis command shows how to display the contents of a VLAN-access map. The fields shown in the display are self-explanatory. Related Commands
show vlan all-portsTo display VLAN information for trunk and access ports, use the show vlan all-ports command in privileged EXEC mode. show vlan all-ports Syntax DescriptionThis command has no arguments or keywords. Command ModesPrivileged EXEC (#) Command History
ExamplesThe following example shows how to display VLAN information for trunk and access ports: Table 33 describes the significant fields shown in the display.
show vlan countersTo display the software-cached counter values, use the show vlan counters command in privileged EXEC mode. show vlan [id vlanid] counters Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesThe show vlan id counters command is not supported on switch virtual interfaces (SVIs). For Layer 2 and Layer 3 VLAN interfaces and router ports, per-interface switching statistics and VLAN-counter information to the Multilayer Switching Feature Card 2 (MSFC2) are exported approximately every 3 minutes. If you enter the show vlan counters command with no arguments, the software-cached counter values for all VLANs are displayed. ExamplesThis example shows how to display the software-cached counter values for a specific VLAN. The fields shown in the display are self-explanatory. Related Commands
show vlan dot1q tag nativeTo display native VLAN-tagging information, use the show vlan dot1q tag native command in privileged EXEC mode. show vlan dot1q tag native Syntax DescriptionThis command has no arguments or keywords. Command ModesPrivileged EXEC (#) Command History
ExamplesThis example shows how to display native VLAN-tagging information. The fields shown in the display are self-explanatory. Related Commands
show vlan filterTo display information about the VLAN filter, use the show vlan filter command in privileged EXEC mode. show vlan filter [access-map map-name | vlan vlan-id | interface interface interface-number] Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesThe show vlan filter map-name interface command accepts only ATM, packet over SONET/SDH (POS), or serial interface types. If your system is not configured with any of these interface types, the interface interface interface-number keyword and arguments are not provided. The interface-number argument designates the module and port number. Valid values for interface-number depend on the specified interface type and the chassis and module that are used. For example, if you specify a Gigabit Ethernet interface and have a 48-port 10/100BASE-T Ethernet module that is installed in a 13-slot chassis, valid values for the module number are from 2 to 13 and valid values for the port number are from 1 to 48. If you do not specify an optional keyword and argument, all mappings are displayed. If you enter access-map map_name, all the VLANs and interfaces that are associated with the specified map are shown. If you enter vlan vlan-id or interface interface interface-number, its associated access map, if existing, is shown. In the output for VLAN access control lists (VACLs) on VLANs, the following applies: •Configured on VLANs—User configured •Active on VLANs—VLAN list on which the VACL is active In the WAN-interface outputs, the following applies: •Configured on interfaces—User configured •Active on Interfaces—Interfaces on which the VACL is active ExamplesThis example shows how to display mappings between the VACLs and the VLANs and the VACLs and the interfaces. The fields shown in the display are self-explanatory. Related Commands
show vlan freeTo display the total number of free VLANs on a router, use the show vlan free command in privileged EXEC mode. show vlan free Syntax DescriptionThis command has no arguments or keywords. Command DefaultAll free VLANs are displayed. Command ModesPrivileged EXEC (#) Usage GuidelinesThe show vlan free command displays the total number of free VLANs on a router. Command History
ExamplesThe following is sample output from the show vlan free command. This example lists the number of free VLANs on a router. The fields shown in the display are self-explanatory. Related Commands
show vlan free summaryTo display the usage summary information for VLANs, use the show free vlan summary command in privileged EXEC mode. show vlan free summary Syntax DescriptionThis command has no arguments or keywords. Command DefaultUsage summary information for all of the free VLANs is displayed. Command ModesPrivileged EXEC (#) Usage GuidelinesThe show vlan free summary command displays the following VLAN information: •Total number of available VLANs •Total number of free VLANs •Total number of used VLANs. Command History
ExamplesThis example shows how to view the summary information for the existing VLANs in the system. The field descriptions shown in the display are self-explanatory. Related Commands
show vlan internal usageTo display information about the internal VLAN allocation, use the show vlan internal usage command in privileged EXEC mode. show vlan [id vlan-id] internal usage Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesIn some cases, the output displays the following: A workaround VLAN is used to enable the Policy Feature Card (PFC)-based policing on the PWAN1 main interface. Without the workaround VLAN, the packets hit the PFC policer twice for PWAN1 because the same VLAN is used when packets traverse the local bus before and after Parallel eXpress Forwarding (PXF) processing. Entering the show vlan internal usage command displays the Optical Services Module (OSM) interfaces and subinterfaces in addition to the regular Ethernet interfaces. To display the associated subinterfaces, enter the show cwan vlan command. The show cwan vlan command displays the mapping between the WAN subinterface and the internal VLANs in use. ExamplesThis example shows how to display the current internal VLAN allocation. The fields shown in the displays are self-explanatory. This example shows how to display the internal VLAN allocation for a specific VLAN: show vlan mappingTo register a mapping of an 802.1Q VLAN to an Inter-Switch Link (ISL) VLAN, use the show vlan mapping command in privileged EXEC mode. show vlan mapping Syntax DescriptionThis command has no arguments or keywords. Command ModesPrivileged EXEC (#) Command History
ExamplesThis example shows how to list the map for an 802.1Q VLAN to an ISL VLAN. The fields shown in the display are self-explanatory. Related Commands
show vlan port provisioningTo display the VLAN port provisioning status, use the show vlan port provisioning command in privileged EXEC mode. show vlan port provisioning Syntax DescriptionThis command has no arguments or keywords. Command ModesCommand History
ExamplesRelated Commands
show vlan private-vlanTo display private VLAN (PVLAN) information, use the show vlan private-vlan command in privileged EXEC mode. show vlan private-vlan [type] Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesIn the show vlan private-vlan type command output display, "normal" displayed as a type indicates a regular VLAN that is configured in a PVLAN. A display of "normal" means that two VLANs have been associated before the type was set and that the PVLAN is not operational. This information is useful for debugging purposes. ExamplesThis example shows how to display information about all currently configured PVLANs: This example shows how to display information about all currently configured PVLAN types: Table 34 describes the fields that are shown in the example.
Related Commands
show vlan remote-spanTo display a list of remote Switched Port Analyzer (RSPAN) VLANs, use the show vlan remote-span command in privileged EXEC mode. show vlan remote-span Syntax DescriptionThis command has no arguments or keywords. Command ModesPrivileged EXEC (#) Command History
ExamplesThis example shows how to display a list of remote SPAN VLANs. The fields shown in the display are self-explanatory. Related Commands
show vlan virtual-portTo display the number of logical virtual ports required, use the show vlan virtual-port command in privileged EXEC mode. show vlan virtual-port [slot number] Syntax Description
Command ModesPrivileged EXEC (#) Command History
ExamplesThis example shows how to display the number of logical virtual ports that are required for a specific slot. The fields shown in the display are self-explanatory. This example shows how to display the number of logical virtual ports that are required for all slots. The fields shown in the display are self-explanatory. show vlan-rangeTo display the VLAN range, use the show vlan-range command in privileged EXEC mode. show vlan-range Syntax DescriptionThis command has no arguments or keywords. Command ModesPrivileged EXEC (#) Command History
ExamplesThe following is sample output from the show vlan-range command. The field descriptions in the display are self-explanatory. Related Commands
show vlansTo display VLAN subinterfaces, use the show vlans command in privileged EXEC mode. show vlans Catalyst 6500 Series Switches and Cisco 7600 Series Routers show vlans [vlan] Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesOn the Catalyst 6500 series switches and Cisco 7600 series routers, the EXEC show vlan command displays information about the Layer 2 VLAN. The privileged EXEC show vlans command displays information about the VLAN subinterface in Layer 3. When entering the show vlans command, you cannot shorten the vlans keyword. If you want to view the Layer 3 statistics, do not use the show vlans command, instead use the show interface vlan vlan-num stats command or the show interface vlan vlan-num accounting command. ExamplesThe following is sample output from the show vlans command: The following is sample output from the show vlans command indicating a native VLAN and a bridged group: This example shows how to display information about the Cisco IOS VLAN subinterfaces: This VLAN is configured as a native VLAN for the following interfaces: The following is sample output from the show vlans command that shows the traffic count on Fast Ethernet subinterfaces: Table 35 describes the significant fields shown in the display.
Related Commands
show vlans dot1qTo display statistics about 802.1Q VLAN subinterfaces, use the show vlans dot1q command in privileged EXEC mode. show vlans dot1q [internal | interface-type interface-number.subinterface-number [detail] | outer-id [interface-type interface-number | second-dot1q [inner-id | any]] [detail]] Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesIf no arguments or keywords are entered, statistics for all of the 802.1Q VLAN IDs are displayed. The any keyword is not supported for IPoQinQ because IP routing is not supported on ambiguous subinterfaces. However, the second-dot1q inner-id keyword and argument can be used on IPoQinQ for a specific inner VLAN ID that is not an ambiguous subinterface. Note On the Cisco 10000 series router, the following is an implementation limitation—when a service policy is applied to a PPPoEoQinQ or IPoQinQ subinterface and the service policy drops some packets, the packets dropped are still displayed in the outgoing packet counters as output. Note For the Cisco ASR 1000 Series Aggregation Services Router only, the command output includes the total number of packets dropped from the shared port adapter (SPA) because of ingress oversubscription on the VLAN. An example of the output is included in the "Cisco ASR 1000 Series Router: Example" section below. Examples802.1Q VLAN Statistics: Example The output from the show vlans dot1q command displays the statistics for all the 802.1Q VLAN IDs. Only the outer VLAN IDs are displayed here. Table 36 describes the significant fields shown in the display.
The following sample output from the show vlans dot1q command displays the statistics for the 802.1Q VLAN subinterface configured on Gigabit Ethernet interface 5/0: Table 37 describes the significant fields shown in the display.
The following sample output from the show vlans dot1q command displays the summary statistics for all of the VLAN subinterfaces under the physical interface Gigabit Ethernet 5/0 that have an outer VLAN ID of 101: The following sample output from the show vlans dot1q command displays the individual subinterface statistics and summary statistics for all the VLAN subinterfaces under the physical interface Gigabit Ethernet 5/0 that have an outer VLAN ID of 101: The following sample output from the show vlans dot1q command displays the statistics for an outer VLAN and inner VLAN ID combination. This is a summary that displays the total for all the subinterfaces on the router that are configured with the specified IDs. Note When multiple inner VLANs are used, the statistics displayed are at subinterface-level granularity, not VLAN-ID granularity. For example, when a range of inner VLAN IDs is assigned to a subinterface, the statistics are reported only at the subinterface level. Statistics are not available for each inner VLAN ID. The following sample output from the show vlans dot1q command displays the statistics for a specific outer VLAN ID of 301 and an inner VLAN ID of any. This is a summary that displays the total for all of the subinterfaces on the router that are configured with the specified IDs. QinQ Subsystem Information: Example The following sample output from the show vlans dot1q command displays some internal information about the QinQ subsystem and is used for troubleshooting purposes (typically by Cisco engineers): Cisco ASR 1000 Series Router: Example The following is an example of the output displayed on the Cisco ASR 1000 series router only. For the Cisco ASR 1000 series router only, the command output includes the total number of packets dropped from the SPA due to ingress over subscription on the VLAN. Table 38 describes the significant fields shown in the display.
Related Commands
show vlans tokenringTo display Token Ring VLANs, use the show vlans tokenring command in user EXEC or privileged EXEC mode. show vlans tokenring Syntax DescriptionThis command has no arguments or keywords. Command Modes User EXEC (>) Command History
ExamplesThe following example shows how to use the show vlans tokenring command. The fields shown in the display are self-explanatory. Router# show vlans tokenring When the show vlans tokenring command is executed on a device with the Token Ring configurations, the output consists of a list of Token Ring interfaces with VLAN configuration. Related Commands
show vlan-switchTo display VLAN information, use the show vlan-switch command in user EXEC or privileged EXEC mode. show vlan-switch [brief | id vlan | internal usage | name name | summary] Syntax Description
Command Modes User EXEC (>) Command History
Usage GuidelinesEach Ethernet switch port and Ethernet repeater group belongs to only one VLAN. Trunk ports can be on multiple VLANs. ExamplesThe following is sample output from the example show vlan-switch command, which displays the VLAN parameters for all VLANs within the administrative domain: Table 39 describes the significant fields shown in the display.
Related Commands
show vtpTo display general information about the VLAN Trunking Protocol (VTP) management domain, status, and counters, use the show vtp command in privileged EXEC mode. show vtp {counters | interface [type/number] | status | password | devices [conflicts]} Syntax Description
Command ModesPrivileged EXEC (#) Command History
Usage GuidelinesIn the output of the show vtp status command, the last modified time is of the modifier itself. For example, the time displayed in the line "Configuration last modified by 7.0.22.11 at 5-5-06 05:51:49", is the time that the modifier (7.0.22.11) last modified the VLAN configuration. ExamplesThe following is sample output from the show vtp counters command: This example shows how to display only those lines in the show vtp output that contain the word Summary: This example shows how to display general information about the VTP management domain: Table 40 describes the significant fields shown in the display.
The following is sample output from the show vtp status command for VTP version 1 and VTP version 2: Table 41 describes the significant fields shown in the display.
The following is sample output from the show vtp status command for all three VTP versions on the Cisco 7600 series routers running Release 12.2(33)SRC and later. This example shows how to verify the configuration when the device is running VTP version 1: This example shows how to verify the configuration when the device is running VTP version 2: This example shows how to verify the configuration when the device is running VTP version 3: Table 42 describes the significant fields shown in the displays.
This example shows how to display information for a specific interface: This example shows how a password is displayed when it is configured using the hidden keyword (VTP version 3 only): This example shows how to display information about all VTP devices in the domain: Table 43 describes the significant fields shown in the display.
Related Commands
shutdown vlanTo shut down local traffic on a specified VLAN, use the shutdown vlan command in global configuration mode. To restart local traffic on the VLAN, use the no form of this command. shutdown vlan vlan-id no shutdown vlan vlan-id Syntax Description
Command DefaultLocal traffic on a specified VLAN is not shut down. Command ModesGlobal configuration (config) Command History
Usage GuidelinesThis command does not support extended-range VLANs. ExamplesThis example shows how to shut down traffic on VLAN 2: snmp trap mac-notification changeTo enable the Simple Network Management Protocol (SNMP) trap notification on a LAN port when MAC addresses are added to or removed from the address table, use the snmp trap mac-notification change command in interface configuration mode. To disable the SNMP trap notification on a LAN port when MAC addresses are added to or removed from the address table, use the no form of this command. snmp trap mac-notification change [added | removed] no snmp trap mac-notification change Syntax Description
Command DefaultThe SNMP trap notification is disabled. Command ModesInterface configuration (config-if) Command History
ExamplesThe following example shows how to enable the SNMP trap notification on a LAN port when MAC addresses are added to the address table: The following example shows how to enable the SNMP trap notification on a LAN port when MAC addresses are removed from the address table: The following example shows how to disable the SNMP trap notification on a LAN port: Related Commands
spanning-tree backbonefastTo enable BackboneFast to allow a blocked port on a switch to change immediately to a listening mode, use the spanning-tree backbonefast command in global configuration mode. To return to the default setting, use the no form of this command. spanning-tree backbonefast no spanning-tree backbonefast Syntax DescriptionThis command has no arguments or keywords. Command DefaultBackboneFast is disabled. Command ModesGlobal configuration (config) Command History
Usage GuidelinesBackboneFast should be enabled on all of the Cisco routers containing an Ethernet switch network module. BackboneFast provides for fast convergence in the network backbone after a spanning-tree topology change. It enables the switch to detect an indirect link failure and to start the spanning-tree reconfiguration sooner than it would under normal spanning-tree rules. Use the show spanning-tree privileged EXEC command to verify your settings. ExamplesThe following example shows how to enable BackboneFast on the switch: Related Commands
spanning-tree bpdufilterTo enable bridge protocol data unit (BPDU) filtering on the interface, use the spanning-tree bpdufilter command in interface configuration mode. To return to the default settings, use the no form of this command. spanning-tree bpdufilter {enable | disable} no spanning-tree bpdufilter Syntax Description
Command DefaultThe setting that is already configured when you enter the spanning-tree portfast bpdufilter default command. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesEntering the spanning-tree bpdufilter enable command to enable BPDU filtering overrides the PortFast configuration. When configuring Layer 2-protocol tunneling on all the service-provider edge switches, you must enable spanning-tree BPDU filtering on the 802.1Q tunnel ports by entering the spanning-tree bpdufilter enable command. BPDU filtering prevents a port from sending and receiving BPDUs. The configuration is applicable to the whole interface, whether it is trunking or not. This command has three states: •spanning-tree bpdufilter enable—Unconditionally enables BPDU filtering on the interface. •spanning-tree bpdufilter disable—Unconditionally disables BPDU filtering on the interface. •no spanning-tree bpdufilter—Enables BPDU filtering on the interface if the interface is in operational PortFast state and if you configure the spanning-tree portfast bpdufilter default command. Use the spanning-tree portfast bpdufilter default command to enable BPDU filtering on all ports that are already configured for PortFast. ExamplesThis example shows how to enable BPDU filtering on this interface: Related Commands
spanning-tree bpduguardTo enable bridge protocol data unit (BPDU) guard on the interface, use the spanning-tree bpduguard command in interface configuration mode. To return to the default settings, use the no form of this command. spanning-tree bpduguard {enable | disable} no spanning-tree bpduguard Syntax Description
Command DefaultThe setting that is already configured when you enter the spanning-tree portfast bpduguard default command. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesBPDU guard prevents a port from receiving BPDUs. Typically, this feature is used in a service-provider environment where the network administrator wants to prevent an access port from participating in the spanning tree. If the port still receives a BPDU, it is put in the error-disabled state as a protective measure. This command has three states: •spanning-tree bpduguard enable—Unconditionally enables BPDU guard on the interface. •spanning-tree bpduguard disable—Unconditionally disables BPDU guard on the interface. •no spanning-tree bpduguard—Enables BPDU guard on the interface if it is in the operational PortFast state and if the spanning-tree portfast bpduguard default command is configured. ExamplesThis example shows how to enable BPDU guard on this interface: Related Commands
spanning-tree bridge assuranceTo enable Bridge Assurance on all network ports on the switch, use the spanning-tree bridge assurance command in global configuration mode. To disable Bridge Assurance, use the no form of this command. spanning-tree bridge assurance no spanning-tree bridge assurance Syntax DescriptionThis command has no arguments or keywords. Command DefaultBridge Assurance is enabled. Command ModesGlobal configuration (config) Command History
Usage GuidelinesBridge Assurance protects against a unidirectional link failure or other software failure and a device that continues to forward data traffic when it is no longer running the spanning tree algorithm. Bridge Assurance is enabled only on spanning tree network ports that are point-to-point links. Both ends of the link must have Bridge Assurance enabled. If the device on one side of the link has Bridge Assurance enabled and the device on the other side either does not support Bridge Assurance or does not have this feature enabled, the connecting port is blocked. Disabling Bridge Assurance causes all configured network ports to behave as normal spanning tree ports. ExamplesThis example shows how to enable Bridge Assurance on all network ports on the switch: This example shows how to disable Bridge Assurance on all network ports on the switch: Related Commands
spanning-tree costTo set the path cost of the interface for Spanning Tree Protocol (STP) calculations, use the spanning-tree cost command in interface configuration mode. To revert to the default value, use the no form of this command. spanning-tree cost cost no spanning-tree cost Syntax Description
Command DefaultThe default path cost is computed from the bandwidth setting of the interface; default path costs are: Ethernet: 10016-Mb Token Ring: 62FDDI: 10FastEthernet: 10ATM 155: 6GigibitEthernet: 1 HSSI: 647 Command ModesInterface configuration (config-if) Command History
Usage GuidelinesWhen you specify a value for the cost argument, higher values indicate higher costs. This range applies regardless of the protocol type specified. ExamplesThe following example shows how to access an interface and set a path cost value of 250 for the spanning tree VLAN associated with that interface: Related Commands
spanning-tree etherchannel guard misconfigTo display an error message when a loop due to a channel misconfiguration is detected, use the spanning-tree etherchannel guard misconfig command in global configuration mode. To disable the error message, use the no form of this command. spanning-tree etherchannel guard misconfig no spanning-tree etherchannel guard misconfig Syntax DescriptionThis command has no arguments or keywords. Command DefaultError messages are displayed. Command ModesGlobal configuration (config) Command History
Usage GuidelinesEtherChannel uses either Port Aggregation Protocol (PAgP) or Link Aggregation Control Protocol (LACP) and does not work if the EtherChannel mode of the interface is enabled using the channel-group group-number mode on command. The spanning-tree etherchannel guard misconfig command detects two types of errors: misconfiguration and misconnection errors. A misconfiguration error is an error between the port-channel and an individual port. A misconnection error is an error between a switch that is channeling more ports and a switch that is not using enough Spanning Tree Protocol (STP) Bridge Protocol Data Units (BPDUs) to detect the error. In this case, the switch will only error disable an EtherChannel if the switch is a nonroot switch. When an EtherChannel-guard misconfiguration is detected, this error message displays: To determine which local ports are involved in the misconfiguration, enter the show interfaces status err-disabled command. To check the EtherChannel configuration on the remote device, enter the show etherchannel summary command on the remote device. After you correct the configuration, enter the shutdown and the no shutdown commands on the associated port-channel interface. ExamplesThis example shows how to enable the EtherChannel-guard misconfiguration: Router(config)# spanning-tree etherchannel guard misconfig Router(config)# Related Commands
spanning-tree extend system-idTo enable the extended-system ID feature on chassis that support 1024 MAC addresses, use the spanning-tree extend system-id command in global configuration mode. To disable the extended system identification, use the no form of this command. spanning-tree extend system-id no spanning-tree extend system-id Syntax DescriptionThis command has no arguments or keywords. Command DefaultEnabled on systems that do not provide 1024 MAC addresses. Command ModesGlobal configuration (config) Command History
Usage GuidelinesThe Catalyst 6500 series switch can support 64 or up to 1024 MAC addresses. For a Catalyst 6500 series switch with 64 MAC addresses, STP uses the extended-system ID and a MAC address to make the bridge ID unique for each VLAN. You cannot disable the extended-system ID on a Catalyst 6500 series switch that supports 64 MAC addresses. Enabling or disabling the extended-system ID updates the bridge IDs of all active Spanning Tree Protocol (STP) instances, which might change the spanning-tree topology. ExamplesThis example shows how to enable the extended-system ID: Related Commands
spanning-tree guardTo enable or disable the guard mode, use the spanning-tree guard command in interface configuration mode. To return to the default settings, use the no form of this command. spanning-tree guard {loop | root | none} no spanning-tree guard Syntax Description
Command DefaultGuard mode is disabled. Command ModesInterface configuration (config-if) Command History
ExamplesThis example shows how to enable root guard: Related Commands
spanning-tree link-typeTo configure a link type for a port, use the spanning-tree link-type command in the interface configuration mode. To return to the default settings, use the no form of this command. spanning-tree link-type {point-to-point | shared} no spanning-tree link-type Syntax Description
Command DefaultLink type is automatically derived from the duplex setting unless you explicitly configure the link type. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesRapid Spanning Tree Protocol Plus (RSTP+) fast transition works only on point-to-point links between two bridges. By default, the switch derives the link type of a port from the duplex mode. A full-duplex port is considered as a point-to-point link while a half-duplex configuration is assumed to be on a shared link. If you designate a port as a shared link, RSTP+ fast transition is forbidden, regardless of the duplex setting. ExamplesThis example shows how to configure the port as a shared link: Related Commands
spanning-tree loopguard defaultTo enable loop guard as a default on all ports of a given bridge, use the spanning-tree loopguard default command in global configuration mode. To disable loop guard, use the no form of this command. spanning-tree loopguard default no spanning-tree loopguard default Syntax DescriptionThis command has no arguments or keywords. Command DefaultLoop guard is disabled. Command ModesGlobal configuration (config) Command History
Usage GuidelinesLoop guard provides additional security in the bridge network. Loop guard prevents alternate or root ports from becoming the designated port due to a failure that could lead to a unidirectional link. Loop guard operates only on ports that are considered point to point by the spanning tree. The individual loop-guard port configuration overrides this command. ExamplesThis example shows how to enable loop guard: Related Commands
spanning-tree modeTo switch between Per-VLAN Spanning Tree+ (PVST+), Rapid-PVST+, and Multiple Spanning Tree (MST) modes, use the spanning-tree mode command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree mode [pvst | mst | rapid-pvst] no spanning-tree mode Syntax Description
Command Defaultpvst Command ModesGlobal configuration (config) Command History
Usage GuidelinesExamplesThis example shows how to switch to MST mode: This example shows how to return to the default mode (PVST+): Related Commands
spanning-tree mstTo set the path cost and port-priority parameters for any Multiple Spanning Tree (MST) instance (including the Common and Internal Spanning Tree [CIST] with instance ID 0), use the spanning-tree mst command in interface configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst instance-id {{cost cost | port-priority priority} | pre-standard} no spanning-tree mst instance-id {{cost | port-priority} | pre-standard} Syntax Description
Command DefaultThe defaults are as follows: •cost depends on the port speed; the faster interface speeds indicate smaller costs. MST always uses long path costs. •priority is 128. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesHigher cost cost values indicate higher costs. When entering the cost, do not include a comma in the entry; for example, enter 1000, not 1,000. Higher port-priority priority values indicate smaller priorities. ExamplesThis example shows how to set the interface path cost: This example shows how to set the interface priority: Related Commands
spanning-tree mst configurationTo enter MST-configuration submode, use the spanning-tree mst configuration command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst configuration no spanning-tree mst configuration Syntax DescriptionThis command has no arguments or keywords. Command DefaultThe default value for the Multiple Spanning Tree (MST) configuration is the default value for all its parameters: •No VLANs are mapped to any MST instance (all VLANs are mapped to the Common and Internal Spanning Tree [CIST] instance). •The region name is an empty string. •The revision number is 0. Command ModesGlobal configuration (config) Command History
Usage GuidelinesThe MST configuration consists of three main parameters: •Instance VLAN mapping—See the instance command •Region name—See the name (MST configuration submode) command •Configuration revision number—See the revision command The abort and exit commands allow you to exit MST configuration submode. The difference between the two commands depends on whether you want to save your changes or not. The exit command commits all the changes before leaving MST configuration submode. If you do not map secondary VLANs to the same instance as the associated primary VLAN, when you exit MST-configuration submode, a warning message displays and lists the secondary VLANs that are not mapped to the same instance as the associated primary VLAN. The warning message is as follows: The abort command leaves MST-configuration submode without committing any changes. Changing an MST-configuration submode parameter can cause connectivity loss. To reduce service disruptions, when you enter MST-configuration submode, make changes to a copy of the current MST configuration. When you are done editing the configuration, you can apply all the changes at once by using the exit keyword, or you can exit the submode without committing any change to the configuration by using the abort keyword. In the unlikely event that two users commit a new configuration at exactly at the same time, this warning message displays: ExamplesThis example shows how to enter MST-configuration submode: This example shows how to reset the MST configuration to the default settings: Related Commands
spanning-tree mst forward-timeTo set the forward-delay timer for all the instances on the Catalyst 6500 series switch, use the spanning-tree mst forward-time command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst forward-time seconds no spanning-tree mst forward-time Syntax Description
Command Defaultseconds is 15. Command ModesGlobal configuration (config) Command History
ExamplesThis example shows how to set the forward-delay timer: Router(config)# Related Commands
spanning-tree mst hello-timeTo set the hello-time delay timer for all the instances on the Catalyst 6500 series switch, use the spanning-tree mst hello-time command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst hello-time seconds no spanning-tree mst hello-time Syntax Description
Command Default2 seconds Command ModesGlobal configuration (config) Command History
Usage GuidelinesIf you do not specify the hello-time value, the value is calculated from the network diameter. ExamplesThis example shows how to set the hello-time delay timer: Router(config)# Related Commands
spanning-tree mst max-ageTo set the max-age timer for all the instances on the Catalyst 6500 series switch, use the spanning-tree mst max-age command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst max-age seconds no spanning-tree mst max-age Syntax Description
Command Default20 seconds Command ModesGlobal configuration (config) Command History
ExamplesThis example shows how to set the max-age timer: Router(config)# Related Commands
spanning-tree mst max-hopsTo specify the number of possible hops in the region before a bridge protocol data unit (BPDU) is discarded, use the spanning-tree mst max-hops command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst max-hops hopnumber no spanning-tree mst max-hops Syntax Description
Command Default20 hops Command ModesGlobal configuration (config) Command History
ExamplesThis example shows how to set the number of possible hops: Router(config)# Related Commands
spanning-tree mst pre-standardTo configure a port to transmit only prestandard bridge protocol data units (BPDUs), use the spanning-tree mst pre-standard command in interface configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst pre-standard no spanning-tree mst pre-standard Syntax DescriptionThis command has no arguments or keywords. Command DefaultThe default is to automatically detect prestandard neighbors. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesEven with the default configuration, the port can receive both prestandard and standard BPDUs. Prestandard BPDUs are based on the Cisco IOS Multiple Spanning Tree (MST) implementation that was created before the IEEE standard was finalized. Standard BPDUs are based on the finalized IEEE standard. If you configure a port to transmit prestandard BPDUs only, the prestandard flag displays in the show spanning-tree commands. The variations of the prestandard flag are as follows: •Pre-STD (or pre-standard in long format)—This flag displays if the port is configured to transmit prestandard BPDUs and if a prestandard neighbor bridge has been detected on this interface. •Pre-STD-Cf (or pre-standard (config) in long format)—This flag displays if the port is configured to transmit prestandard BPDUs but a prestandard BPDU has not been received on the port, the autodetection mechanism has failed, or a misconfiguration, if there is no prestandard neighbor, has occurred. •Pre-STD-Rx (or pre-standard (rcvd) in long format)—This flag displays when a prestandard BPDU has been received on the port but it has not been configured to send prestandard BPDUs. The port will send prestandard BPDUs, but we recommend that you change the port configuration so that the interaction with the prestandard neighbor does not rely only on the autodetection mechanism. If the MST configuration is not compatible with the prestandard (if it includes an instance ID greater than 15), only standard MST BPDUs are transmitted, regardless of the STP configuration on the port. ExamplesThis example shows how to configure a port to transmit only prestandard BPDUs: Related Commands
spanning-tree mst priorityTo set the bridge priority for an instance, use the spanning-tree mst priority command in global configuration mode. To return to the default setting, use the no form of this command. spanning-tree mst instance priority priority no spanning-tree mst priority Syntax Description
Command Defaultpriority is 32768. Command ModesGlobal configuration (config) Command History
Usage GuidelinesYou can set the bridge priority in increments of 4096 only. When you set the priority, valid values are 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960, 45056, 49152, 53248, 57344, and 61440. You can set the priority to 0 to make the switch root. You can enter instance as a single instance or a range of instances, for example, 0-3,5,7-9. ExamplesThis example shows how to set the bridge priority: Related Commands
spanning-tree mst rootTo designate the primary and secondary root switch and set the timer value for an instance, use the spanning-tree mst root command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree mst instance root {primary | secondary} [diameter diameter [hello-time seconds]] no spanning-tree mst instance root Syntax Description
Command DefaultThe spanning-tree mst root command has no default settings. Command ModesGlobal configuration (config) Command History
Usage GuidelinesYou can enter instance as a single instance or a range of instances, for example, 0-3,5,7-9. The spanning-tree mst root secondary value is 16384. The diameter diameter and hello-time seconds keywords and arguments are available for instance 0 only. If you do not specify the seconds argument, the value for it is calculated from the network diameter. ExamplesThis example shows how to designate the primary root switch and timer values for an instance: Related Commands
spanning-tree mst simulate pvst (interface)To override the global Per-VLAN Spanning Tree (PVST) simulation setting for a port, use the spanning-tree mst simulate pvst interface command in interface configuration mode. To return to the default PVST simulation setting, use the no form of this command. spanning-tree mst simulate pvst [disable] no spanning-tree mst simulate pvst Syntax Description
Command DefaultPVST simulation is enabled. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesPVST simulation is enabled by default so that an interface can interoperate between Multiple Spanning Tree (MST) and Rapid Per-VLAN Spanning Tree Plus (PVST+). To prevent an accidental connection to a device that does not run MST as the default Spanning Tree Protocol (STP) mode, you can disable PVST simulation. If you disable PVST simulation, the MST-enabled port moves to the blocking state once it detects it is connected to a Rapid PVST+-enabled port. This port remains in the inconsistent state until the port stops receiving Bridge Protocol Data Units (BPDUs), and then the port resumes the normal STP transition process. ExamplesThis example shows how to prevent a port from automatically interoperating with a connecting device that is running Rapid PVST+: Related Commands
spanning-tree mst simulate pvst globalTo enable Per-VLAN Spanning Tree (PVST) simulation globally, enter the spanning-tree mst simulate pvst global command in global configuration mode. To disable PVST simulation globally, enter the no form of this command. spanning-tree mst simulate pvst global no spanning-tree mst simulate pvst global Syntax DescriptionThis command has no arguments or keywords. Command DefaultPVST simulation is enabled. Command ModesGlobal configuration (config) Command History
Usage GuidelinesPVST simulation is enabled by default so that all interfaces on the device interoperate between Multiple Spanning Tree (MST) and Rapid Per-VLAN Spanning Tree Plus (PVST+). To prevent an accidental connection to a device that does not run MST as the default Spanning Tree Protocol (STP) mode, you can disable PVST simulation. If you disable PVST simulation, the MST-enabled port moves to the blocking state once it detects it is connected to a Rapid PVST+-enabled port. This port remains in the inconsistent state until the port stops receiving Bridge Protocol Data Units (BPDUs), and then the port resumes the normal STP transition process. To override the global PVST simulation setting for a port, enter the spanning-tree mst simulate pvst interface command in the interface command mode. ExamplesThis example shows how to prevent the switch from automatically interoperating with a connecting device that is running Rapid PVST+: Related Commands
spanning-tree pathcost methodTo set the default path-cost calculation method, use the spanning-tree pathcost method command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree pathcost method {long | short} no spanning-tree pathcost method Syntax Description
Command Defaultshort Command ModesGlobal configuration (config) Command History
Usage GuidelinesThis command applies to all the spanning-tree instances on the Catalyst 6500 series switch. The long path-cost calculation method utilizes all 32 bits for path-cost calculation and yields values in the range of 1 through 200,000,000. The short path-cost calculation method (16 bits) yields values in the range of 1 through 65535. ExamplesThis example shows how to set the default path-cost calculation method to long: This example shows how to set the default path-cost calculation method to short: Related Commands
spanning-tree portfast (interface)To enable PortFast mode where the interface is immediately put into the forwarding state upon linkup without waiting for the timer to expire, use the spanning-tree portfast command in interface configuration mode. To return to the default settings, use the no form of this command. spanning-tree portfast spanning-tree portfast {disable | edge [trunk] | network | trunk} no spanning-tree portfast Syntax Description
Command DefaultThe settings that are configured by the spanning-tree portfast default command. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesYou should use this command only with interfaces that connect to end stations; otherwise, an accidental topology loop could cause a data-packet loop and disrupt the Catalyst 6500 series switch and network operation. An interface with PortFast mode enabled is moved directly to the spanning-tree forwarding state when linkup occurs without waiting for the standard forward-time delay. Be careful when using the no spanning-tree portfast command. This command does not disable PortFast if the spanning-tree portfast default command is enabled. This command has these states: •spanning-tree portfast—This command enables PortFast unconditionally on the given port. •spanning-tree portfast disable—This command explicitly disables PortFast for the given port. The configuration line shows up in the running configuration because it is not the default. •spanning-tree portfast edge—This command allows you to configure PortFast edge mode on the given port. •spanning-tree portfast network—This command allows you to configure PortFast network mode on the given port. •spanning-tree portfast [edge] trunk—This command allows you to configure PortFast on trunk ports. The edge keyword is required with trunk in Cisco IOS Release 12.2(33)SXI and later releases. Note If you enter the spanning-tree portfast trunk command, the port is configured for PortFast even in the access mode. •no spanning-tree portfast—This command implicitly enables PortFast if you define the spanning-tree portfast default command in global configuration mode and if the port is not a trunk port. If you do not configure PortFast globally, the no spanning-tree portfast command is equivalent to the spanning-tree portfast disable command. ExamplesThis example shows how to enable PortFast mode in releases earlier than Cisco IOS Release 12.2(33)SXI: This example shows how to enable PortFast edge mode in Cisco IOS Release 12.2(33)SXI and later releases: Related Commands
spanning-tree portfast bpdufilter defaultTo enable bridge protocol data unit (BPDU) filtering by default on all PortFast ports, use the spanning-tree portfast bpdufilter default command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree portfast bpdufilter default no spanning-tree portfast bpdufilter default Syntax DescriptionThis command has no arguments or keywords. Command DefaultDisabled Command ModesGlobal configuration (config) Command History
Usage GuidelinesThe spanning-tree portfast bpdufilter command enables BPDU filtering globally on PortFast ports. BPDU filtering prevents a port from sending or receiving any BPDUs. You can override the effects of the portfast bpdufilter default command by configuring BPDU filtering at the interface level. Note Be careful when enabling BPDU filtering. The feature's functionality is different when you enable it on a per-port basis or globally. When enabled globally, BPDU filtering is applied only on ports that are in an operational PortFast state. Ports send a few BPDUs at linkup before they effectively filter outbound BPDUs. If a BPDU is received on an edge port, it immediately loses its operational PortFast status and BPDU filtering is disabled. When enabled locally on a port, BPDU filtering prevents the Catalyst 6500 series switch from receiving or sending BPDUs on this port. ExamplesThis example shows how to enable BPDU filtering by default: Related Commands
spanning-tree portfast bpduguard defaultTo enable bridge protocol data unit (BPDU) guard by default on all PortFast ports, use the spanning-tree portfast bpduguard default command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree portfast bpduguard default no spanning-tree portfast bpduguard default Syntax DescriptionThis command has no arguments or keywords. Command DefaultDisabled Command ModesGlobal configuration (config) Command History
Usage GuidelinesBPDU guard disables a port if it receives a BPDU. BPDU guard is applied only on ports that are PortFast enabled and are in an operational PortFast state. ExamplesThis example shows how to enable BPDU guard by default: Related Commands
spanning-tree portfast defaultTo enable PortFast by default on all access ports, use the spanning-tree portfast default command in global configuration mode. To disable PortFast by default on all access ports, use the no form of this command. spanning-tree portfast {edge [bpdufilter | bpduguard] | network | normal} default no spanning-tree portfast {edge [bpdufilter | bpduguard] | network | normal} default Syntax Description
Note These keywords are available only in Cisco IOS Release 12.2(33)SXI and later releases. Command DefaultPortFast is disabled by default on all access ports. Command ModesGlobal configuration (config) Command History
Usage GuidelinesAn interface with PortFast mode enabled is moved directly to the spanning-tree forwarding state when linkup occurs without waiting for the standard forward-time delay. You can enable PortFast mode on individual interfaces using the spanning-tree portfast (interface) command. ExamplesThis example shows how to enable PortFast by default on all access ports in releases earlier than Cisco IOS Release 12.2(33)SXI: This example shows how to enable PortFast edge mode with BPDU Guard by default on all access ports in Cisco IOS Release 12.2(33)SXI and later releases: Related Commands
spanning-tree port-priorityTo set an interface priority when two bridges tie for position as the root bridge, use the spanning-tree port-priority command in interface configuration mode. To revert to the default value, use the no form of this command. spanning-tree port-priority port-priority no spanning-tree port-priority Syntax Description
Command DefaultThe port priority is 128. Command ModesInterface configuration (config-if) Command History
Usage GuidelinesThe priority you set breaks the tie. ExamplesThe following example shows how to increase the likelihood that spanning-tree instance 20 is chosen as the root-bridge on interface Ethernet 2/0: Related Commands
spanning-tree transmit hold-countTo specify the transmit hold count, use the spanning-tree transmit hold-count command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree transmit hold-count value no spanning-tree transmit hold-count Syntax Description
Command Defaultvalue is 6. Command ModesGlobal configuration (config) Command History
Usage GuidelinesThis command is supported on all spanning-tree modes. The transmit hold count determines the number of BPDUs that can be sent before pausing for 1 second. Note Changing this parameter to a higher value may have a significant impact on CPU utilization, especially in rapid-Per-VLAN Spanning Tree (PVST) mode. Lowering this parameter could slow convergence in some scenarios. We recommend that you do not change the value from the default setting. If you change the value setting, enter the show running-config command to verify the change. If you delete the command, use the show spanning-tree mst command to verify the deletion. ExamplesThis example shows how to specify the transmit hold count: Related Commands
spanning-tree uplinkfastTo enable UplinkFast, use the spanning-tree uplinkfast command in global configuration mode. To disable UplinkFast, use the no form of this command. spanning-tree uplinkfast [max-update-rate packets-per-second] no spanning-tree uplinkfast [max-update-rate] Syntax Description
Command DefaultThe defaults are as follows: •UplinkFast is disabled. •packets-per-second is 150 packets per second. Command ModesGlobal configuration (config) Command History
Usage GuidelinesUse this command only on access switches. When you configure UplinkFast, the bridge priority is changed to 49152 so that this switch is not selected as root. All interface path costs of all spanning-tree interfaces that belong to the specified spanning-tree instances also increase by 3000. When spanning tree detects that the root interface has failed, UplinkFast causes an immediate switchover to an alternate root interface, transitioning the new root interface directly to the forwarding state. During this time, a topology change notification is sent. To minimize the disruption that is caused by the topology change, a multicast packet is sent to 01-00-0C-CD-CD-CD for each station address in the forwarding bridge except for those associated with the old root interface. Use the spanning-tree uplinkfast max-update-rate command to enable UplinkFast (if it is not already enabled) and change the rate at which update packets are sent. Use the no form of this command to return to the default rate. ExamplesThis example shows how to enable UplinkFast and set the maximum rate to 200 packets per second: Related Commands
spanning-tree vlanTo configure Spanning Tree Protocol (STP) on a per-virtual LAN (VLAN) basis, use the spanning-tree vlan command in global configuration mode. To return to the default settings, use the no form of this command. spanning-tree vlan vlan-id [forward-time seconds | hello-time seconds | max-age seconds | priority priority | protocol protocol | [root {primary | secondary} [diameter net-diameter [hello-time seconds]]]] no spanning-tree vlan vlan-id [forward-time | hello-time | max-age | priority | protocol | root] Syntax Description
Command DefaultThe defaults are: •forward-time—15 seconds •hello-time—2 seconds •max-age—20 seconds •priority—The default with IEEE STP enabled is 32768; the default with STP enabled is 128. •protocol—IEEE •root—No STP root When you issue the no spanning-tree vlan xx root command the following parameters are reset to their defaults: •priority—The default with IEEE STP enabled is 32768; the default with STP enabled is 128. •hello-time—2 seconds •forward-time—15 seconds •max-age—20 seconds Command ModesGlobal configuration (config) Command History
Usage GuidelinesWhen you set the max-age seconds parameter, if a bridge does not hear bridge protocol data units (BPDUs) from the root bridge within the specified interval, it assumes that the network has changed and recomputes the spanning-tree topology. Valid values for protocol are dec (Digital STP), ibm (IBM STP), ieee (IEEE Ethernet STP), and vlan-bridge (VLAN Bridge STP). The spanning-tree root primary command alters this switch's bridge priority to 8192. If you enter the spanning-tree root primary command and the switch does not become the root switch, then the bridge priority is changed to 100 less than the bridge priority of the current bridge. If the switch still does not become the root, an error results. The spanning-tree root secondary command alters this switch's bridge priority to 16384. If the root switch should fail, this switch becomes the next root switch. Use the spanning-tree root commands on backbone switches only. The spanning-tree etherchannel guard misconfig command detects two types of errors: misconfiguration and misconnection errors. A misconfiguration error is an error between the port-channel and an individual port. A misconnection error is an error between a switch that is channeling more ports and a switch that is not using enough Spanning Tree Protocol (STP) Bridge Protocol Data Units (BPDUs) to detect the error. In this case, the switch will only error disable an EtherChannel if the switch is a nonroot switch. ExamplesThe following example shows how to enable spanning tree on VLAN 200: The following example shows how to configure the switch as the root switch for VLAN 10 with a network diameter of 4: The following example shows how to configure the switch as the secondary root switch for VLAN 10 with a network diameter of 4: Related Commands
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