- Preface
- Using the Command Line Interface
- Cisco IE 3000 Switch Cisco IOS Commands - aaa accounting through reserved-only
- Cisco IE 3000 Switch Cisco IOS Commands - rmon collection through show vtp
- Cisco IE 3000 Switch Cisco IOS Commands - shutdown through vtp
- Cisco IE 3000 Switch Bootloader Commands
- Cisco IE 3000 Switch Debug Commands
- Cisco IE 3000 Switch Show Platform Commands
- Acknowledgments for Open-Source Software
- ComRef
- shutdown
- shutdown vlan
- small-frame violation rate
- snmp-server enable traps
- snmp-server host
- snmp trap mac-notification change
- spanning-tree backbonefast
- spanning-tree bpdufilter
- spanning-tree bpduguard
- spanning-tree cost
- spanning-tree etherchannel guard misconfig
- spanning-tree extend system-id
- spanning-tree guard
- spanning-tree link-type
- spanning-tree loopguard default
- spanning-tree mode
- spanning-tree mst configuration
- spanning-tree mst cost
- spanning-tree mst forward-time
- spanning-tree mst hello-time
- spanning-tree mst max-age
- spanning-tree mst max-hops
- spanning-tree mst port-priority
- spanning-tree mst pre-standard
- spanning-tree mst priority
- spanning-tree mst root
- spanning-tree port-priority
- spanning-tree portfast (global configuration)
- spanning-tree portfast (interface configuration)
- spanning-tree transmit hold-count
- spanning-tree uplinkfast
- spanning-tree vlan
- speed
- srr-queue bandwidth limit
- srr-queue bandwidth shape
- srr-queue bandwidth share
- storm-control
- switchport
- switchport access
- switchport autostate exclude
- switchport backup interface
- switchport block
- switchport host
- switchport mode
- switchport mode private-vlan
- switchport nonegotiate
- switchport port-security
- switchport port-security aging
- switchport priority extend
- switchport private-vlan
- switchport protected
- switchport trunk
- switchport voice vlan
- system mtu
- test cable-diagnostics tdr
- test relay
- traceroute mac
- traceroute mac ip
- trust
- udld
- udld port
- udld reset
- vlan
- vlan access-map
- vlan dot1q tag native
- vlan filter
- vmps reconfirm (privileged EXEC)
- vmps reconfirm (global configuration)
- vmps retry
- vmps server
- vtp (global configuration)
- vtp (interface configuration)
- vtp primary
shutdown
Use the shutdown interface configuration command to disable an interface. Use the no form of this command to restart a disabled interface.
Command Modes
Usage Guidelines
The shutdown command causes a port to stop forwarding. You can enable the port with the no shutdown command.
The no shutdown command has no effect if the port is a static-access port assigned to a VLAN that has been deleted, suspended, or shut down. The port must first be a member of an active VLAN before it can be re-enabled.
The shutdown command disables all functions on the specified interface.
This command also marks the interface as unavailable. To see if an interface is disabled, use the show interfaces privileged EXEC command. An interface that has been shut down is shown as administratively down in the display.
Examples
These examples show how to disable and re-enable a port:
You can verify your settings by entering the show interfaces privileged EXEC command.
shutdown vlan
Use the shutdown vlan global configuration command to shut down (suspend) local traffic on the specified VLAN. Use the no form of this command to restart local traffic on the VLAN.
Command Modes
Usage Guidelines
The shutdown vlan command does not change the VLAN information in the VTP database. The command shuts down local traffic, but the switch still advertises VTP information.
small-frame violation rate
Use the small-frame violation rate pps interface configuration command to configure the rate (threshold) for an interface to be error disabled when it receives VLAN-tagged packets that are small frames (67 bytes or less) at the specified rate. Use the no form of this command to return to the default setting.
small-frame violation rate pps
Command Modes
Usage Guidelines
This command enables the rate (threshold) for a port to be error disabled when it receives small frames. Small frames are considered packets that are 67 frames or less.
Use the errdisable detect cause small-frame global configuration command to globally enable the small-frames threshold for each port.
You can configure the port to be automatically re-enabled by using the errdisable recovery cause small-frame global configuration command. You configure the recovery time by using the errdisable recovery interval interval global configuration command.
Examples
This example shows how to enable the small-frame arrival rate feature so that the port is error disabled if incoming small frames arrived at 10,000 pps.
You can verify your setting by entering the show interfaces privileged EXEC command.
snmp-server enable traps
Use the snmp-server enable traps global configuration command to enable the switch to send Simple Network Management Protocol (SNMP) notifications for various traps or inform requests to the network management system (NMS). Use the no form of this command to return to the default setting.
snmp-server enable traps [ bgp | bridge [ newroot ] [ topologychange ] | cluster | config | copy-config | cpu [ threshold ] | dot1x [auth-fail-vlan | guest-vlan | no-auth-fail-vlan | no-guest-vlan] | entity | envmon [ fan | shutdown | status | supply | temperature ] | errdisable [ notification-rate value ] | flash [ insertion | removal ] | hsrp | ipmulticast | mac-notification [ change ] [ move ] [ threshold ] | msdp | ospf [ cisco-specific | errors | lsa | rate-limit | retransmit | state-change ] | pim [ invalid-pim-message | neighbor-change | rp-mapping-change ] | port-security [ trap-rate value ] | rtr | snmp [ authentication | coldstart | linkdown | linkup | warmstart ] | storm-contro l trap-rate value | stpx [ inconsistency ] [ root-inconsistency ] [ loop-inconsistency ] | syslog | tty | vlan-membership | vlancreate | vlandelete | vtp]
no snmp-server enable traps [ bgp | bridge [ newroot ] [ topologychange ] | cluster | config | copy-config | cpu [ threshold ] | dot1x [auth-fail-vlan | guest-vlan | no-auth-fail-vlan | no-guest-vlan] | entity | envmon [ fan | shutdown | status | supply | temperature ] | errdisable [ notification-rate value ] | flash [ insertion | removal ] | hsrp | ipmulticast | mac-notification [ change ] [ move ] [ threshold ] | msdp | ospf [ cisco-specific | errors | lsa | rate-limit | retransmit | state-change ] | pim [ invalid-pim-message | neighbor-change | rp-mapping-change ] | port-security [ trap-rate value ] | rtr | snmp [ authentication | coldstart | linkdown | linkup | warmstart ] | storm-contro l trap-rate value | stpx [ inconsistency ] [ root-inconsistency ] [ loop-inconsistency ] | syslog | tty | vlan-membership | vlancreate | vlandelete | vtp]
Syntax Description
Note Though visible in the command-line help strings, the insertion, and removal keywords are not supported. The snmp-server enable informs global configuration command is not supported. To enable the sending of SNMP inform notifications, use the snmp-server enable traps global configuration command combined with the snmp-server host host-addr informs global configuration command.
Command Modes
Usage Guidelines
Specify the host (NMS) that receives the traps by using the snmp-server host global configuration command. If no trap types are specified, all types are sent.
When supported, use the snmp-server enable traps command to enable sending of traps or informs.
Note Informs are not supported in SNMPv1.
To enable more than one type of trap, you must enter a separate snmp-server enable traps command for each trap type.
To set the CPU threshold notification types and values, use the process cpu threshold type global configuration command.
snmp-server host
Use the snmp-server host global configuration command to specify the recipient (host) of a Simple Network Management Protocol (SNMP) notification operation. Use the no form of this command to remove the specified host.
snmp-server host host-addr [ informs | traps ] [ version { 1 | 2c | 3 { auth | noauth | priv }] [ vrf vrf-instance ] { community-string [ notification-type ]}
no snmp-server host host-addr [ informs | traps ] [ version { 1 | 2c | 3 { auth | noauth | priv }] [ vrf vrf-instance ] community-string
Syntax Description
Command Default
This command is disabled by default. No notifications are sent.
If you enter this command with no keywords, the default is to send all trap types to the host. No informs are sent to this host.
If no version keyword is present, the default is Version 1.
If Version 3 is selected and no authentication keyword is entered, the default is the noauth (noAuthNoPriv) security level.
Command Modes
Usage Guidelines
SNMP notifications can be sent as traps or inform requests. Traps are unreliable because the receiver does not send acknowledgments when it receives traps. The sender cannot determine if the traps were received. However, an SNMP entity that receives an inform request acknowledges the message with an SNMP response PDU. If the sender never receives the response, the inform request can be sent again. Thus, informs are more likely to reach their intended destinations.
However, informs consume more resources in the agent and in the network. Unlike a trap, which is discarded as soon as it is sent, an inform request must be held in memory until a response is received or the request times out. Traps are also sent only once, but an inform might be retried several times. The retries increase traffic and contribute to a higher overhead on the network.
If you do not enter an snmp-server host command, no notifications are sent. To configure the switch to send SNMP notifications, you must enter at least one snmp-server host command. If you enter the command with no keywords, all trap types are enabled for the host. To enable multiple hosts, you must enter a separate snmp-server host command for each host. You can specify multiple notification types in the command for each host.
If a local user is not associated with a remote host, the switch does not send informs for the auth (authNoPriv) and the priv (authPriv) authentication levels.
When multiple snmp-server host commands are given for the same host and kind of notification (trap or inform), each succeeding command overwrites the previous command. Only the last snmp-server host command is in effect. For example, if you enter an snmp-server host inform command for a host and then enter another snmp-server host inform command for the same host, the second command replaces the first.
The snmp-server host command is used with the snmp-server enable traps global configuration command. Use the snmp-server enable traps command to specify which SNMP notifications are sent globally. For a host to receive most notifications, at least one snmp-server enable traps command and the snmp-server host command for that host must be enabled. Some notification types cannot be controlled with the snmp-server enable traps command. For example, some notification types are always enabled. Other notification types are enabled by a different command.
The no snmp-server host command with no keywords disables traps, but not informs, to the host. To disable informs, use the no snmp-server host informs command.
Examples
This example shows how to configure a unique SNMP community string named comaccess for traps and prevent SNMP polling access with this string through access-list 10:
This example shows how to send the SNMP traps to the host specified by the name myhost.cisco.com . The community string is defined as comaccess :
This example shows how to enable the switch to send all traps to the host myhost.cisco.com by using the community string public :
Related Commands
snmp trap mac-notification change
Use the snmp trap mac-notification change interface configuration command to enable the Simple Network Management Protocol (SNMP) MAC address change notification trap on a specific Layer 2 interface. Use the no form of this command to return to the default setting.
snmp trap mac-notification change { added | removed }
Command Modes
Usage Guidelines
Even though you enable the notification trap for a specific interface by using the snmp trap mac-notification change command, the trap is generated only when you enter the snmp-server enable traps mac-notification change and the mac address-table notification change global configuration commands.
Examples
This example shows how to enable the MAC notification trap when a MAC address is added to a port:
You can verify your settings by entering the show mac address-table notification change interface privileged EXEC command.
Related Commands
clear mac address-table notification |
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Displays the MAC address notification settings for all interfaces or on the specified interface when the interface keyword is appended. |
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Sends the SNMP MAC notification traps when the mac-notification keyword is appended. |
spanning-tree backbonefast
Use the spanning-tree backbonefast global configuration command to enable the BackboneFast feature. Use the no form of the command to return to the default setting.
Command Modes
Usage Guidelines
You can configure the BackboneFast feature for rapid PVST+ or for multiple spanning-tree (MST) mode, but the feature remains disabled (inactive) until you change the spanning-tree mode to PVST+.
BackboneFast starts when a root port or blocked port on a switch receives inferior BPDUs from its designated switch. An inferior BPDU identifies a switch that declares itself as both the root bridge and the designated switch. When a switch receives an inferior BPDU, it means that a link to which the switch is not directly connected (an indirect link) has failed (that is, the designated switch has lost its connection to the root switch. If there are alternate paths to the root switch, BackboneFast causes the maximum aging time on the interfaces on which it received the inferior BPDU to expire and allows a blocked port to move immediately to the listening state. BackboneFast then transitions the interface to the forwarding state. For more information, see the software configuration guide for this release.
Enables BackboneFast on all supported switches to allow the detection of indirect link failures and to start the spanning-tree reconfiguration sooner.
Examples
This example shows how to enable BackboneFast on the switch:
You can verify your setting by entering the show spanning-tree summary privileged EXEC command.
Related Commands
show spanning-tree summary |
spanning-tree bpdufilter
Use the spanning-tree bpdufilter interface configuration command to prevent an interface from sending or receiving bridge protocol data units (BPDUs). Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
You can enable the BPDU filtering feature when the switch is operating in the per-VLAN spanning-tree plus (PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode.
You can globally enable BPDU filtering on all Port Fast-enabled interfaces by using the spanning-tree portfast bpdufilter default global configuration command.
You can use the spanning-tree bpdufilter interface configuration command to override the setting of the spanning-tree portfast bpdufilter default global configuration command.
Examples
This example shows how to enable the BPDU filtering feature on a port:
You can verify your setting by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree bpduguard
Use the spanning-tree bpduguard interface configuration command to put an interface in the error-disabled state when it receives a bridge protocol data unit (BPDU). Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
The BPDU guard feature provides a secure response to invalid configurations because you must manually put the interface back in service. Use the BPDU guard feature in a service-provider network to prevent an interface from being included in the spanning-tree topology.
You can enable the BPDU guard feature when the switch is operating in the per-VLAN spanning-tree plus (PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode.
You can globally enable BPDU guard on all Port Fast-enabled interfaces by using the spanning-tree portfast bpduguard default global configuration command.
You can use the spanning-tree bpduguard interface configuration command to override the setting of the spanning-tree portfast bpduguard default global configuration command.
Examples
This example shows how to enable the BPDU guard feature on a port:
You can verify your setting by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree cost
Use the spanning-tree cost interface configuration command to set the path cost for spanning-tree calculations. If a loop occurs, spanning tree considers the path cost when selecting an interface to place in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree [ vlan vlan-id ] cost cost
no spanning-tree [ vlan vlan-id ] cost
Syntax Description
Command Modes
Usage Guidelines
When you configure the cost , higher values represent higher costs.
If you configure an interface with both the spanning-tree vlan vlan-id cost cost command and the spanning-tree cost cost command, the spanning-tree vlan vlan-id cost cost command takes effect.
Examples
This example shows how to set the path cost to 250 on a port:
This example shows how to set a path cost to 300 for VLANs 10, 12 to 15, and 20:
You can verify your settings by entering the show spanning-tree interface interface-id privileged EXEC command.
Related Commands
show spanning-tree interface interface-id |
Displays spanning-tree information for the specified interface. |
spanning-tree vlan priority |
Sets the switch priority for the specified spanning-tree instance. |
spanning-tree etherchannel guard misconfig
Use the spanning-tree etherchannel guard misconfig global configuration command to display an error message when the switch detects an EtherChannel misconfiguration. Use the no form of this command to disable the feature.
Command Modes
Usage Guidelines
When the switch detects an EtherChannel misconfiguration, this error message appears:
To show switch ports that are in the misconfigured EtherChannel, use the show interfaces status err-disabled privileged EXEC command. To verify the EtherChannel configuration on a remote device, use the show etherchannel summary privileged EXEC command on the remote device.
When a port is in the error-disabled state because of an EtherChannel misconfiguration, you can bring it out of this state by entering the errdisable recovery cause channel-misconfig global configuration command, or you can manually re-enable it by entering the shutdown and no shut down interface configuration commands.
Examples
This example shows how to enable the EtherChannel guard misconfiguration feature:
You can verify your settings by entering the show spanning-tree summary privileged EXEC command.
Related Commands
errdisable recovery cause channel-misconfig |
Enables the timer to recover from the EtherChannel misconfiguration error-disabled state. |
show etherchannel summary |
Displays EtherChannel information for a channel as a one-line summary per channel-group. |
show interfaces status err-disabled |
spanning-tree extend system-id
Use the spanning-tree extend system-id global configuration command to enable the extended system ID feature.
spanning-tree extend system-id
Note Though visible in the command-line help strings, the no version of this command is not supported. You cannot disable the extended system ID feature.
Command Modes
Usage Guidelines
The switch supports the IEEE 802.1t spanning-tree extensions. Some of the bits previously used for the switch priority are now used for the extended system ID (VLAN identifier for the per-VLAN spanning-tree plus [PVST+] and rapid PVST+ or as an instance identifier for the multiple spanning tree [MST]).
The spanning tree uses the extended system ID, the switch priority, and the allocated spanning-tree MAC address to make the bridge ID unique for each VLAN or multiple spanning-tree instance.
Support for the extended system ID affects how you manually configure the root switch, the secondary root switch, and the switch priority of a VLAN. For more information, see the “spanning-tree mst root” and the “spanning-tree vlan” sections.
If your network consists of switches that do not support the extended system ID and switches that do support it, it is unlikely that the switch with the extended system ID support will become the root switch. The extended system ID increases the switch priority value every time the VLAN number is greater than the priority of the connected switches.
Related Commands
show spanning-tree summary |
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Configures the MST root switch priority and timers based on the network diameter. |
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spanning-tree vlan priority |
Sets the switch priority for the specified spanning-tree instance. |
spanning-tree guard
Use the spanning-tree guard interface configuration command to enable root guard or loop guard on all the VLANs associated with the selected interface. Root guard restricts which interface is allowed to be the spanning-tree root port or the path-to-the root for the switch. Loop guard prevents alternate or root ports from becoming designated ports when a failure creates a unidirectional link. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
You can enable root guard or loop guard when the switch is operating in the per-VLAN spanning-tree plus (PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode.
When root guard is enabled, if spanning-tree calculations cause an interface to be selected as the root port, the interface transitions to the root-inconsistent (blocked) state to prevent the customer’s switch from becoming the root switch or being in the path to the root. The root port provides the best path from the switch to the root switch.
When the no spanning-tree guard or the no spanning-tree guard none command is entered, root guard is disabled for all VLANs on the selected interface. If this interface is in the root-inconsistent (blocked) state, it automatically transitions to the listening state.
Do not enable root guard on interfaces that will be used by the UplinkFast feature. With UplinkFast, the backup interfaces (in the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the backup interfaces used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and prevented from reaching the forwarding state. The UplinkFast feature is not available when the switch is operating in the rapid-PVST+ or MST mode.
Loop guard is most effective when it is configured on the entire switched network. When the switch is operating in PVST+ or rapid-PVST+ mode, loop guard prevents alternate and root ports from becoming designated ports, and spanning tree does not send bridge protocol data units (BPDUs) on root or alternate ports. When the switch is operating in MST mode, BPDUs are not sent on nonboundary interfaces if the interface is blocked by loop guard in all MST instances. On a boundary interface, loop guard blocks the interface in all MST instances.
To disable root guard or loop guard, use the spanning-tree guard none interface configuration command. You cannot enable both root guard and loop guard at the same time.
You can override the setting of the spanning-tree loopguard default global configuration command by using the spanning-tree guard loop interface configuration command.
Examples
This example shows how to enable root guard on all the VLANs associated with the specified port:
This example shows how to enable loop guard on all the VLANs associated with the specified port:
You can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands . |
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Prevents alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link. |
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Configures the MST root switch priority and timers based on the network diameter. |
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spanning-tree vlan priority |
Sets the switch priority for the specified spanning-tree instance. |
spanning-tree link-type
Use the spanning-tree link-type interface configuration command to override the default link-type setting, which is determined by the duplex mode of the interface, and to enable rapid spanning-tree transitions to the forwarding state. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
You can override the default setting of the link type by using the spanning-tree link-type command. For example, a half-duplex link can be physically connected point-to-point to a single interface on a remote switch running the Multiple Spanning Tree Protocol (MSTP) or the rapid per-VLAN spanning-tree plus (rapid-PVST+) protocol and be enabled for rapid transitions.
Examples
This example shows how to specify the link type as shared (regardless of the duplex setting) and to prevent rapid transitions to the forwarding state:
You can verify your setting by entering the show spanning-tree mst interface interface-id or the show spanning-tree interface interface-id privileged EXEC command.
Related Commands
Restarts the protocol migration process (force the renegotiation with neighboring switches) on all interfaces or on the specified interface. |
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show spanning-tree interface interface-id |
Displays spanning-tree state information for the specified interface. |
show spanning-tree mst interface interface-id |
spanning-tree loopguard default
Use the spanning-tree loopguard default global configuration command to prevent alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
You can enable the loop guard feature when the switch is operating in the per-VLAN spanning-tree plus (PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode.
Loop guard is most effective when it is configured on the entire switched network. When the switch is operating in PVST+ or rapid-PVST+ mode, loop guard prevents alternate and root ports from becoming designated ports, and spanning tree does not send bridge protocol data units (BPDUs) on root or alternate ports. When the switch is operating in MST mode, BPDUs are not sent on nonboundary interfaces if the interface is blocked by loop guard in all MST instances. On a boundary interface, loop guard blocks the interface in all MST instances.
Loop guard operates only on interfaces that the spanning tree identifies as point-to-point.
You can override the setting of the spanning-tree loopguard default global configuration command by using the spanning-tree guard loop interface configuration command.
Examples
This example shows how to globally enable loop guard:
You can verify your settings by entering the show running-config privileged EXEC comm and.
Related Commands
Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands . |
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spanning-tree guard loop |
Enables the loop guard feature on all the VLANs associated with the specified interface. |
spanning-tree mode
Use the spanning-tree mode global configuration command to enable per-VLAN spanning-tree plus (PVST+), rapid PVST+, or multiple spanning tree (MST) on your switch. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
The switch supports PVST+, rapid PVST+, and MSTP, but only one version can be active at any time: All VLANs run PVST+, all VLANs run rapid PVST+, or all VLANs run MSTP.
When you enable the MST mode, RSTP is automatically enabled.
spanning-tree mst configuration
Use the spanning-tree mst configuration global configuration command to enter multiple spanning-tree (MST) configuration mode through which you configure the MST region. Use the no form of this command to return to the default settings.
Command Modes
Usage Guidelines
The spanning-tree mst configuration command enables the MST configuration mode. These configuration commands are available:
- abort : exits the MST region configuration mode without applying configuration changes.
- exit : exits the MST region configuration mode and applies all configuration changes.
- instance instance-id vlan vlan-range : maps VLANs to an MST instance. The range for the instance-id is 1 to 4094. The range for vlan-range is 1 to 4094. You can specify a single VLAN identified by VLAN ID number, a range of VLANs separated by a hyphen, or a series of VLANs separated by a comma.
- name name : sets the configuration name. The name string has a maximum length of 32 characters and is case sensitive.
- no : negates the instance , name , and revision commands or sets them to their defaults.
- private-vlan : Though visible in the command-line help strings, this command is not supported.
- revision version : sets the configuration revision number. The range is 0 to 65535.
- show [ current | pending ] : displays the current or pending MST region configuration.
In MST mode, the switch supports up to 65 MST instances. The number of VLANs that can be mapped to a particular MST instance is unlimited.
When you map VLANs to an MST instance, the mapping is incremental, and VLANs specified in the command are added to or removed from the VLANs that were previously mapped. To specify a range, use a hyphen; for example, instance 1 vlan 1-63 maps VLANs 1 to 63 to MST instance 1. To specify a series, use a comma; for example, instance 1 vlan 10, 20, 30 maps VLANs 10, 20, and 30 to MST instance 1.
All VLANs that are not explicitly mapped to an MST instance are mapped to the common and internal spanning tree (CIST) instance (instance 0) and cannot be unmapped from the CIST by using the no form of the command.
For two or more switches to be in the same MST region, they must have the same VLAN mapping, the same configuration revision number, and the same name.
Examples
This example shows how to enter MST configuration mode, map VLANs 10 to 20 to MST instance 1, name the region region1 , set the configuration revision to 1, display the pending configuration, apply the changes, and return to global configuration mode:
This example shows how to add VLANs 1 to 100 to the ones already mapped (if any) to instance 2, to move VLANs 40 to 60 that were previously mapped to instance 2 to the CIST instance, to add VLAN 10 to instance 10, and to remove all the VLANs mapped to instance 2 and map them to the CIST instance:
You can verify your settings by entering the show pending MST configuration command.
Related Commands
show spanning-tree mst configuration |
spanning-tree mst cost
Use the spanning-tree mst cost interface configuration command to set the path cost for multiple spanning-tree (MST) calculations. If a loop occurs, spanning tree considers the path cost when selecting an interface to put in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree mst instance-id cost cost
Command Modes
Examples
This example shows how to set a path cost of 250 on a port associated with instances 2 and 4:
You can verify your settings by entering the show spanning-tree mst interface interface-id privileged EXEC command.
Related Commands
show spanning-tree mst interface interface-id |
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Configures the switch priority for the specified spanning-tree instance. |
spanning-tree mst forward-time
Use the spanning-tree mst forward-time global configuration command to set the forward-delay time for all multiple spanning-tree (MST) instances. The forwarding time specifies how long each of the listening and learning states last before the interface begins forwarding. Use the no form of this command to return to the default setting.
spanning-tree mst forward-time seconds
Command Modes
Usage Guidelines
Changing the spanning-tree mst forward-time command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree forwarding time to 18 seconds for all MST instances:
You can verify your setting by entering the show spanning-tree mst privileged EXEC command.
spanning-tree mst hello-time
Use the spanning-tree mst hello-time global configuration command to set the interval between hello bridge protocol data units (BPDUs) sent by root switch configuration messages. Use the no form of this command to return to the default setting.
spanning-tree mst hello-time seconds
Command Modes
Usage Guidelines
After you set the spanning-tree mst max-age seconds global configuration command, if a switch does not receive BPDUs from the root switch within the specified interval, the switch recomputes the spanning-tree topology. The max-age setting must be greater than the hello-time setting.
Changing the spanning-tree mst hello-time command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree hello time to 3 seconds for all multiple spanning-tree (MST) instances:
You can verify your setting by entering the show spanning-tree mst privileged EXEC command.
spanning-tree mst max-age
Use the spanning-tree mst max-age global configuration command to set the interval between messages that the spanning tree receives from the root switch. If a switch does not receive a bridge protocol data unit (BPDU) message from the root switch within this interval, it recomputes the spanning-tree topology. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
After you set the spanning-tree mst max-age seconds global configuration command, if a switch does not receive BPDUs from the root switch within the specified interval, the switch recomputes the spanning-tree topology. The max-age setting must be greater than the hello-time setting.
Changing the spanning-tree mst max-age command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree max-age to 30 seconds for all multiple spanning-tree (MST) instances:
You can verify your setting by entering the show spanning-tree mst privileged EXEC command.
spanning-tree mst max-hops
Use the spanning-tree mst max-hops global configuration command to set the number of hops in a region before the bridge protocol data unit (BPDU) is discarded and the information held for an interface is aged. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
The root switch of the instance always sends a BPDU (or M-record) with a cost of 0 and the hop count set to the maximum value. When a switch receives this BPDU, it decrements the received remaining hop count by one and propagates the decremented count as the remaining hop count in the generated M-records. A switch discards the BPDU and ages the information held for the interface when the count reaches 0.
Changing the spanning-tree mst max-hops command affects all spanning-tree instances.
Examples
This example shows how to set the spanning-tree max-hops to 10 for all multiple spanning-tree (MST) instances:
You can verify your setting by entering the show spanning-tree mst privileged EXEC command.
spanning-tree mst port-priority
Use the spanning-tree mst port-priority interface configuration command to configure an interface priority. If a loop occurs, the Multiple Spanning Tree Protocol (MSTP) can find the interface to put in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree mst instance-id port-priority priority
no spanning-tree mst instance-id port-priority
Syntax Description
Command Modes
Usage Guidelines
You can assign higher priority values (lower numerical values) to interfaces that you want selected first and lower priority values (higher numerical values) that you want selected last. If all interfaces have the same priority value, the multiple spanning tree (MST) puts the interface with the lowest interface number in the forwarding state and blocks other interfaces.
Examples
This example shows how to increase the likelihood that the interface associated with spanning-tree instances 20 and 22 is placed into the forwarding state if a loop occurs:
You can verify your settings by entering the show spanning-tree mst interface interface-id privileged EXEC command.
Related Commands
show spanning-tree mst interface interface-id |
|
Sets the switch priority for the specified spanning-tree instance. |
spanning-tree mst pre-standard
Use the spanning-tree mst pre-standard interface configuration command to configure a port to send only prestandard bridge protocol data units (BPDUs).
Command Modes
Usage Guidelines
The port can accept both prestandard and standard BPDUs. If the neighbor types are mismatched, only the common and internal spanning tree (CIST) runs on this interface.
Note If a switch port is connected to a switch running prestandard Cisco IOS software, you must use the spanning-tree mst pre-standard interface configuration command on the port. If you do not configure the port to send only prestandard BPDUs, the Multiple STP (MSTP) performance might diminish.
When the port is configured to automatically detect prestandard neighbors, the prestandard flag always appears in the show spanning-tree mst commands.
Examples
This example shows how to configure a port to send only prestandard BPDUs:
You can verify your settings by entering the show spanning-tree mst privileged EXEC command.
Related Commands
show spanning-tree mst instance-id |
Displays multiple spanning-tree (MST) information, including the prestandard flag, for the specified interface. |
spanning-tree mst priority
Use the spanning-tree mst priority global configuration command to set the switch priority for the specified spanning-tree instance. Use the no form of this command to return to the default setting.
spanning-tree mst instance-id priority priority
no spanning-tree mst instance-id priority
Syntax Description
Command Modes
Examples
This example shows how to set the spanning-tree priority to 8192 for multiple spanning-tree instances (MST) 20 to 21:
You can verify your settings by entering the show spanning-tree mst instance-id privileged EXEC command.
Related Commands
show spanning-tree mst instance-id |
|
spanning-tree mst root
Use the spanning-tree mst root global configuration command to configure the multiple spanning-tree (MST) root switch priority and timers based on the network diameter. Use the no form of this command to return to the default settings.
spanning-tree mst
instance-id
root
{
primary
|
secondary
} [
diameter
net-diameter
[
hello-time
seconds
]]
no spanning-tree mst instance-id root
Syntax Description
Command Modes
Usage Guidelines
Use the spanning-tree mst instance-id root command only on backbone switches.
Whe n you enter the spanning-tree mst instance-id root command, the software tries to set a high enough priority to make this switch the root of the spanning-tree instance. Because of the extended system ID support, the switch sets the switch priority for the instance to 24576 if this value will cause this switch to become the root for the specified instance. If any root switch for the specified instance has a switch priority lower than 24576, the switch sets its own priority to 4096 less than the lowest switch priority. (4096 is the value of the least-significant bit of a 4-bit switch priority value.)
When y ou enter the spanning-tree mst instance-id root secondary command, because of support for the extended system ID, the software changes the switch priority from the default value (32768) to 28672. If the root switch fails, this switch becomes the next root switch (if the other switches in the network use the default switch priority of 32768 and are therefore unlikely to become the root switch).
Examples
This example shows how to configure the switch as the root switch for instance 10 with a network diameter of 4:
This example shows how to configure the switch as the secondary root switch for instance 10 with a network diameter of 4:
You can verify your settings by entering the show spanning-tree mst instance-id privileged EXEC command.
Related Commands
show spanning-tree mst instance-id |
|
Sets the interval between hello BPDUs sent by root switch configuration messages. |
|
Sets the interval between messages that the spanning tree receives from the root switch. |
|
Sets the number of hops in a region before the BPDU is discarded. |
spanning-tree port-priority
Use the spanning-tree port-priority interface configuration command to configure an interface priority. If a loop occurs, spanning tree can find the interface to put in the forwarding state. Use the no form of this command to return to the default setting.
spanning-tree [ vlan vlan-id ] port-priority priority
no spanning-tree [ vlan vlan-id ] port-priority
Syntax Description
Command Modes
Usage Guidelines
If the variable vlan-id is omitted, the command applies to the spanning-tree instance associated with VLAN 1.
You can set the priority on a VLAN that has no interfaces assigned to it. The setting takes effect when you assign the interface to the VLAN.
If you configure an interface with both the spanning-tree vlan vlan-id port-priority priority command and the spanning-tree port-priority priority command, the spanning-tree vlan vlan-id port-priority priority command takes effect.
Examples
This example shows how to increase the likelihood that a port will be put in the forwarding state if a loop occurs:
This example shows how to set the port-priority value on VLANs 20 to 25:
You can verify your settings by entering the show spanning-tree interface interface-id privileged EXEC command.
Related Commands
show spanning-tree interface interface-id |
Displays spanning-tree information for the specified interface. |
spanning-tree vlan priority |
Sets the switch priority for the specified spanning-tree instance. |
spanning-tree portfast (global configuration)
Use the spanning-tree portfast global configuration command to globally enable bridge protocol data unit (BPDU) filtering on Port Fast-enabled interfaces, the BPDU guard feature on Port Fast-enabled interfaces, or the Port Fast feature on all nontrunking interfaces. The BPDU filtering feature prevents the switch interface from sending or receiving BPDUs. The BPDU guard feature puts Port Fast-enabled interfaces that receive BPDUs in an error-disabled state. Use the no form of this command to return to the default settings.
spanning-tree portfast { bpdufilter default | bpduguard default | default }
no spanning-tree portfast { bpdufilter default | bpduguard default | default }
Syntax Description
Command Modes
Usage Guidelines
You can enable these features when the switch is operating in the per-VLAN spanning-tree plus (PVST+) rapid-PVST+, or the multiple spanning-tree (MST) mode.
Use the spanning-tree portfast bpdufilter default global configuration command to globally enable BPDU filtering on interfaces that are Port Fast-enabled (the interfaces are in a Port Fast-operational state). The interfaces still send a few BPDUs at link-up before the switch begins to filter outbound BPDUs. You should globally enable BPDU filtering on a switch so that hosts connected to switch interfaces do not receive BPDUs. If a BPDU is received on a Port Fast-enabled interface, the interface loses its Port Fast-operational status and BPDU filtering is disabled.
You can override the spanning-tree portfast bpdufilter default global configuration command by using the spanning-tree bdpufilter interface configuration command.
Use the spanning-tree portfast bpduguard default global configuration command to globally enable BPDU guard on interfaces that are in a Port Fast-operational state. In a valid configuration, Port Fast-enabled interfaces do not receive BPDUs. Receiving a BPDU on a Port Fast-enabled interface signals an invalid configuration, such as the connection of an unauthorized device, and the BPDU guard feature puts the interface in the error-disabled state. The BPDU guard feature provides a secure response to invalid configurations because you must manually put the interface back in service. Use the BPDU guard feature in a service-provider network to prevent an access port from participating in the spanning tree.
You can override the spanning-tree portfast bpduguard default global configuration command by using the spanning-tree bdpuguard interface configuration command.
Use the spanning-tree portfast default global configuration command to globally enable the Port Fast feature on all nontrunking interfaces. Configure Port Fast only on interfaces that connect to end stations; otherwise, an accidental topology loop could cause a data packet loop and disrupt switch and network operation. A Port Fast-enabled interface moves directly to the spanning-tree forwarding state when linkup occurs without waiting for the standard forward-delay time.
You can override the spanning-tree portfast default global configuration command by using the spanning-tree portfast interface configuration command. You can use the no spanning-tree portfast default global configuration command to disable Port Fast on all interfaces unless they are individually configured with the spanning-tree portfast interface configuration command.
Examples
This example shows how to globally enable the BPDU filtering feature:
This example shows how to globally enable the BPDU guard feature:
This example shows how to globally enable the Port Fast feature on all nontrunking interfaces:
You can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree portfast (interface configuration)
Use the spanning-tree portfast interface configuration command to enable the Port Fast feature on an interface in all its associated VLANs. When the Port Fast feature is enabled, the interface changes directly from a blocking state to a forwarding state without making the intermediate spanning-tree state changes. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
Use this feature only on interfaces that connect to end stations; otherwise, an accidental topology loop could cause a data packet loop and disrupt switch and network operation.
To enable Port Fast on trunk ports, you must use the spanning-tree portfast trunk interface configuration command. The spanning-tree portfast command is not supported on trunk ports.
You can enable this feature when the switch is operating in the per-VLAN spanning-tree plus (PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode.
This feature affects all VLANs on the interface.
An interface with the Port Fast feature enabled is moved directly to the spanning-tree forwarding state without the standard forward-time delay.
You can use the spanning-tree portfast default global configuration command to globally enable the Port Fast feature on all nontrunking interfaces. However, the spanning-tree portfast interface configuration command can override the global setting.
If you configure the spanning-tree portfast default global configuration command, you can disable Port Fast on an interface that is not a trunk interface by using the spanning-tree portfast disable interface configuration command.
Examples
This example shows how to enable the Port Fast feature on a port:
You can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
spanning-tree transmit hold-count
Use the spanning-tree transmit hold-count global configuration command to configure the number of bridge protocol data units (BPDUs) sent every second. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
Increasing the transmit hold-count value can have a significant impact on CPU utilization when the switch is in rapid-per-VLAN spanning-tree plus (rapid-PVST+) mode. Decreasing this value might slow down convergence. We recommend using the default setting.
Examples
This example shows how to set the transmit hold count to 8:
You can verify your setting by entering the show spanning-tree mst privileged EXEC command.
spanning-tree uplinkfast
Use the spanning-tree uplinkfast global configuration command to accelerate the choice of a new root port when a link or switch fails or when the spanning tree reconfigures itself. Use the no form of this command to return to the default setting.
spanning-tree uplinkfast [ max-update-rate pkts-per-second ]
Command Modes
Usage Guidelines
Use this command only on access switches.
You can configure the UplinkFast feature for rapid PVST+ or for multiple spanning-tree (MST) mode, but the feature remains disabled (inactive) until you change the spanning-tree mode to PVST+.
When you enable UplinkFast, it is enabled for the entire switch and cannot be enabled for individual VLANs.
When UplinkFast is enabled, the switch priority of all VLANs is set to 49152. If you change the path cost to a value less than 3000 and you enable UplinkFast or UplinkFast is already enabled, the path cost of all interfaces and VLAN trunks is increased by 3000 (if you change the path cost to 3000 or above, the path cost is not altered). The changes to the switch priority and the path cost reduces the chance that a switch will become the root switch.
When UplinkFast is disabled, the switch priorities of all VLANs and path costs of all interfaces are set to default values if you did not modify them from their defaults.
When spanning tree detects that the root port has failed, UplinkFast immediately changes to an alternate root port, changing the new root port directly to forwarding state. During this time, a topology change notification is sent.
Do not enable the root guard on interfaces that will be used by the UplinkFast feature. With UplinkFast, the backup interfaces (in the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the backup interfaces used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and prevented from reaching the forwarding state.
If you set the max-update-rate to 0, station-learning frames are not generated, so the spanning-tree topology converges more slowly after a loss of connectivity.
Examples
This example shows how to enable UplinkFast:
You can verify your setting by entering the show spanning-tree summary privileged EXEC command.
Related Commands
show spanning-tree summary |
|
spanning-tree vlan root primary |
spanning-tree vlan
Use the spanning-tree vlan global configuration command to configure spanning tree on a per-VLAN basis. Use the no form of this command to return to the default setting.
spanning-tree vlan
vlan-id
[
forward-time
seconds
|
hello-time
seconds
|
max-age
seconds
|
priority
priority
|
root
{
primary
|
secondary
} [
diameter
net-diameter
[
hello-time
seconds
]]]
no spanning-tree vlan vlan-id [ forward-time | hello-time | max-age | priority | root ]
Syntax Description
Command Modes
Usage Guidelines
Disabling the STP causes the VLAN to stop participating in the spanning-tree topology. Interfaces that are administratively down remain down. Received BPDUs are forwarded like other multicast frames. The VLAN does not detect and prevent loops when STP is disabled.
You can disable the STP on a VLAN that is not currently active and verify the change by using the show running-config or the show spanning-tree vlan vlan-id privileged EXEC command. The setting takes effect when the VLAN is activated.
When disabling or re-enabling the STP, you can specify a range of VLANs that you want to disable or enable.
When a VLAN is disabled and then enabled, all assigned VLANs continue to be its members. However, all spanning-tree bridge parameters are returned to their previous settings (the last setting before the VLAN was disabled).
You can enable spanning-tree options on a VLAN that has no interfaces assigned to it. The setting takes effect when you assign interfaces to it.
When setting the max-age seconds, if a switch does not receive BPDUs from the root switch within the specified interval, it recomputes the spanning-tree topology. The max-age setting must be greater than the hello-time setting.
The spanning-tree vlan vlan-id root command should be used only on backbone switches.
When you enter the spanning-tree vlan vlan-id root command, the software checks the switch priority of the current root switch for each VLAN. Because of the extended system ID support, the switch sets the switch priority for the specified VLAN to 24576 if this value will cause this switch to become the root for the specified VLAN. If any root switch for the specified VLAN has a switch priority lower than 24576, the switch sets its own priority for the specified VLAN to 4096 less than the lowest switch priority. (4096 is the value of the least-significant bit of a 4-bit switch priority value.)
When you enter the spanning-tree vlan vlan-id root secondary command, because of support for the extended system ID, the software changes the switch priority from the default value (32768) to 28672. If the root switch should fail, this switch becomes the next root switch (if the other switches in the network use the default switch priority of 32768, and therefore, are unlikely to become the root switch).
Examples
This example shows how to disable the STP on VLAN 5:
You can verify your setting by entering the show spanning-tree privileged EXEC command. In this instance, VLAN 5 does not appear in the list.
This example shows how to set the spanning-tree forwarding time to 18 seconds for VLANs 20 and 25:
This example shows how to set the spanning-tree hello-delay time to 3 seconds for VLANs 20 to 24:
This example shows how to set spanning-tree max-age to 30 seconds for VLAN 20:
This example shows how to reset the max-age parameter to the default value for spanning-tree instance 100 and 105 to 108:
This example shows how to set the spanning-tree priority to 8192 for VLAN 20:
This example shows how to configure the switch as the root switch for VLAN 10 with a network diameter of 4:
This example shows how to configure the switch as the secondary root switch for VLAN 10 with a network diameter of 4:
You can verify your settings by entering the show spanning-tree vlan vlan-id privileged EXEC command.
Related Commands
show spanning-tree vlan |
|
Enables the root guard or the loop guard feature for all the VLANs associated with the selected interface. |
|
Globally enables the BPDU filtering or the BPDU guard feature on Port Fast-enabled interfaces or enables the Port Fast feature on all nontrunking interfaces. |
|
Enables the Port Fast feature on an interface in all its associated VLANs. |
|
Enables the UplinkFast feature, which accelerates the choice of a new root port. |
speed
Use the speed interface configuration command to specify the speed of a 10/100 Mb/s or 10/100/1000 Mb/s port. Use the no or default form of this command to return the port to its default value.
speed { 10 | 100 | 1000 | auto [ 10 | 100 | 1000 ] | nonegotiate }
Syntax Description
Command Modes
Usage Guidelines
Except for the 1000BASE-T SFP modules, if an SFP module port is connected to a device that does not support autonegotiation, you can configure the speed to not negotiate ( nonegotiate ).
If the speed is set to auto , the switch negotiates with the device at the other end of the link for the speed setting and then forces the speed setting to the negotiated value. The duplex setting remains as configured on each end of the link, which could result in a duplex setting mismatch.
If both ends of the line support autonegotiation, we highly recommend the default autonegotiation settings. If one interface supports autonegotiation and the other end does not, do use the auto setting on the supported side, but set the duplex and speed on the other side.
For guidelines on setting the switch speed and duplex parameters, see the “Configuring Interface Characteristics” chapter in the software configuration guide for this release.
Examples
This example shows how to set the speed on a port to 100 Mb/s:
This example shows how to set a port to autonegotiate at only 10 Mb/s:
This example shows how to set a port to autonegotiate at only 10 or 100 Mb/s:
You can verify your settings by entering the show interfaces privileged EXEC command.
srr-queue bandwidth limit
Use the srr-queue bandwidth limit interface configuration command to limit the maximum output on a port. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
If you configure this command to 80 percent, the port is idle 20 percent of the time. The line rate drops to 80 percent of the connected speed. These values are not exact because the hardware adjusts the line rate in increments of six.
Note The egress queue default settings are suitable for most situations. You should change them only when you have a thorough understanding of the egress queues and if these settings do not meet your quality of service (QoS) solution.
Examples
This example shows how to limit a port to 800 Mb/s:
You can verify your settings by entering the show mls qos interface [ interface-id ] queueing privileged EXEC command.
Related Commands
Maps class of service (CoS) values to egress queue or maps CoS values to a queue and to a threshold ID. |
|
Maps Differentiated Services Code Point (DSCP) values to an egress queue or maps DSCP values to a queue and to a threshold ID. |
|
Configures the weighted tail-drop (WTD) thresholds, guarantees the availability of buffers, and configures the maximum memory allocation for the queue-set. |
|
show mls qos interface queueing |
|
Assigns the shaped weights and enables bandwidth shaping on the four egress queues mapped to a port. |
|
Assigns the shared weights and enables bandwidth sharing on the four egress queues mapped to a port. |
srr-queue bandwidth shape
Use the srr-queue bandwidth shape interface configuration command to assign the shaped weights and to enable bandwidth shaping on the four egress queues mapped to a port. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
In shaped mode, the queues are guaranteed a percentage of the bandwidth, and they are rate-limited to that amount. Shaped traffic does not use more than the allocated bandwidth even if the link is idle. Use shaping to smooth bursty traffic or to provide a smoother output over time.
The shaped mode overrides the shared mode.
If you configure a shaped queue weight to 0 by using the srr-queue bandwidth shape interface configuration command, this queue participates in shared mode. The weight specified with the srr-queue bandwidth shape command is ignored, and the weights specified with the srr-queue bandwidth share interface configuration command for a queue come into effect.
When configuring queues for the same port for both shaping and sharing, make sure that you configure the lowest numbered queue for shaping.
Note The egress queue default settings are suitable for most situations. You should change them only when you have a thorough understanding of the egress queues and if these settings do not meet your QoS solution.
Examples
This example shows how to configure the queues for the same port for both shaping and sharing. Because the weight ratios for queues 2, 3, and 4 are set to 0, these queues operate in shared mode. The bandwidth weight for queue 1 is 1/8, which is 12.5 percent. Queue 1 is guaranteed this bandwidth and limited to it; it does not extend its slot to the other queues even if the other queues have no traffic and are idle. Queues 2, 3, and 4 are in shared mode, and the setting for queue 1 is ignored. The bandwidth ratio allocated for the queues in shared mode is 4/(4+4+4), which is 33 percent:
Related Commands
Maps class of service (CoS) values to an egress queue or maps CoS values to a queue and to a threshold ID. |
|
Maps Differentiated Services Code Point (DSCP) values to an egress queue or maps DSCP values to a queue and to a threshold ID. |
|
Configures the weighted tail-drop (WTD) thresholds, guarantees the availability of buffers, and configures the maximum memory allocation to a queue-set. |
|
show mls qos interface queueing |
|
Assigns the shared weights and enables bandwidth sharing on the four egress queues mapped to a port. |
srr-queue bandwidth share
Use the srr-queue bandwidth share interface configuration command switch to assign the shared weights and to enable bandwidth sharing on the four egress queues mapped to a port. The ratio of the weights is the ratio of frequency in which the shaped round robin (SRR) scheduler dequeues packets from each queue. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
The absolute value of each weight is meaningless, and only the ratio of parameters is used.
In shared mode, the queues share the bandwidth among them according to the configured weights. The bandwidth is guaranteed at this level but not limited to it. For example, if a queue empties and does not require a share of the link, the remaining queues can expand into the unused bandwidth and share it among themselves.
If you configure a shaped queue weight to 0 by using the srr-queue bandwidth shape interface configuration command, this queue participates in SRR shared mode. The weight specified with the srr-queue bandwidth shape command is ignored, and the weights specified with the srr-queue bandwidth share interface configuration command for a queue take effect.
When configuring queues for the same port for both shaping and sharing, make sure that you configure the lowest numbered queue for shaping.
Note The egress queue default settings are suitable for most situations. You should change them only when you have a thorough understanding of the egress queues and if these settings do not meet your QoS solution.
Examples
This example shows how to configure the weight ratio of the SRR scheduler running on an egress port. Four queues are used. The bandwidth ratio allocated for each queue in shared mode is 1/(1+2+3+4), 2/(1+2+3+4), 3/(1+2+3+4), and 4/(1+2+3+4), which is 10 percent, 20 percent, 30 percent, and 40 percent for queues 1, 2, 3, and 4. This means that queue 4 has four times the bandwidth of queue 1, twice the bandwidth of queue 2, and one-and-a-third times the bandwidth of queue 3.
Related Commands
Maps class of service (CoS) values to an egress queue or maps CoS values to a queue and to a threshold ID. |
|
Maps Differentiated Services Code Point (DSCP) values to an egress queue or maps DSCP values to a queue and to a threshold ID. |
|
Configures the weighted tail-drop (WTD) thresholds, guarantees the availability of buffers, and configures the maximum memory allocation to a queue-set. |
|
show mls qos interface queueing |
|
Assigns the shaped weights and enables bandwidth shaping on the four egress queues mapped to a port. |
storm-control
Use the storm-control interface configuration command to enable broadcast, multicast, or unicast storm control and to set threshold levels on an interface. Use the no form of this command to return to the default setting.
storm-control {{ broadcast | multicast | unicast } level { level [ level-low ] | bps bps [ bps-low ] | pps pps [ pps-low ]}} | { action { shutdown | trap }}
no storm-control {{ broadcast | multicast | unicast } level } | { action { shutdown | trap }}
Syntax Description
Command Modes
Usage Guidelines
The storm-control suppression level can be entered as a percentage of total bandwidth of the port, as a rate in packets per second at which traffic is received, or as a rate in bits per second at which traffic is received.
When specified as a percentage of total bandwidth, a suppression value of 100 percent means that no limit is placed on the specified traffic type. A value of level 0 0 means that all broadcast, multicast, or unicast traffic on that port is blocked. Storm control is enabled only when the rising suppression level is less than 100 percent. If no other storm-control configuration is specified, the default action is to filter the traffic causing the storm and to send no SNMP traps.
Note When the storm control threshold for multicast traffic is reached, all multicast traffic except control traffic, such as bridge protocol data unit (BDPU) and Cisco Discovery Protocol (CDP) frames, are blocked.However, the switch does not differentiate between routing updates, such as Open Shortest Path First (OSPF) and regular multicast data traffic, so both types of traffic are blocked.
The trap and shutdown options are independent of each other.
If you configure the action to be taken as shutdown (the port is error-disabled during a storm) when a packet storm is detected, you must use the no shutdown interface configuration command to bring the interface out of this state. If you do not specify the shutdown action, specify the action as trap (the switch generates a trap when a storm is detected).
When a storm occurs and the action is to filter traffic, if the falling suppression level is not specified, the switch blocks all traffic until the traffic rate drops below the rising suppression level. If the falling suppression level is specified, the switch blocks traffic until the traffic rate drops below this level.
Note Storm control is supported on physical interfaces. You can also configure storm control on an EtherChannel. When storm control is configured on an EtherChannel, the storm control settings propagate to the EtherChannel physical interfaces.
When a broadcast storm occurs and the action is to filter traffic, the switch blocks only broadcast traffic.
For more information, see the software configuration guide for this release.
Examples
This example shows how to enable broadcast storm control with a 75.5-percent rising suppression level:
This example shows how to enable unicast storm control on a port with a 87-percent rising suppression level and a 65-percent falling suppression level:
This example shows how to enable multicast storm control on a port with a 2000-packets-per-second rising suppression level and a 1000-packets-per-second falling suppression level:
This example shows how to enable the shutdown action on a port:
switchport
Use the switchport interface configuration command with no keywords to put an interface that is in Layer 3 mode into Layer 2 mode for Layer 2 configuration. Use the no form of this command to put an interface in Layer 3 mode.
Use the no switchport command (without parameters) to set the interface to the routed-interface status and to erase all Layer 2 configurations. You must use this command before assigning an IP address to a routed port.
Note Layer 3 mode is supported only when the switch is running the IP services image.
Command Modes
Usage Guidelines
Entering the no switchport command shuts the port down and then re-enables it, which might generate messages on the device to which the port is connected.
When you put an interface that is in Layer 2 mode into Layer 3 mode (or the reverse), the previous configuration information related to the affected interface might be lost, and the interface is returned to its default configuration.
Note If an interface is configured as a Layer 3 interface, you must first enter this switchport command with no keywords to configure the interface as a Layer 2 port. Then you can enter additional switchport commands with keywords, as shown on the pages that follow.
Examples
This example shows how to cause an interface to cease operating as a Layer 2 port and become a Cisco-routed port:
This example shows how to cause the port interface to cease operating as a Cisco-routed port and convert to a Layer 2 switched interface:
Related Commands
show interfaces switchport |
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings. |
Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands . |
switchport access
Use the switchport access interface configuration command to configure a port as a static-access or dynamic-access port. If the switchport mode is set to access , the port operates as a member of the specified VLAN. If set to dynamic , the port starts discovery of VLAN assignment based on the incoming packets it receives. Use the no form of this command to reset the access mode to the default VLAN for the switch.
switchport access vlan { vlan-id | dynamic }
Syntax Description
Command Modes
Usage Guidelines
The no switchport access command resets the access mode VLAN to the appropriate default VLAN for the device.
The port must be in access mode before the switchport access vlan command can take effect.
An access port can be assigned to only one VLAN.
The VMPS server (such as a Catalyst 6000 series switch) must be configured before a port is configured as dynamic.
These restrictions apply to dynamic-access ports:
- The software implements the VLAN Query Protocol (VQP) client, which can query a VMPS such as a Catalyst 6000 series switch. The switches are not VMPS servers. The VMPS server must be configured before a port is configured as dynamic.
- Use dynamic-access ports only to connect end stations. Connecting them to switches or routers (that use bridging protocols) can cause a loss of connectivity.
- Configure the network so that STP does not put the dynamic-access port into an STP blocking state. The Port Fast feature is automatically enabled on dynamic-access ports.
- Dynamic-access ports can only be in one VLAN and do not use VLAN tagging.
- Dynamic-access ports cannot be configured as
– Members of an EtherChannel port group (dynamic-access ports cannot be grouped with any other port, including other dynamic ports).
Examples
This example shows how to change a switched port interface that is operating in access mode to operate in VLAN 2 instead of the default VLAN:
You can verify your setting by entering the show interfaces interface-id switchport privileged EXEC command and examining information in the Administrative Mode and Operational Mode rows.
Related Commands
show interfaces switchport |
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings. |
switchport autostate exclude
Use the switchport autostate exclude interface configuration command to exclude an interface from the VLAN interface (switch virtual interface) line-state up or down calculation. Use the no form of this command to return to the default setting.
no switchport autostate exclude
Note This command is available only when the switch is running the IP services image.
Command Modes
Usage Guidelines
Enter the switchport autostate exclude command on a Layer 2 access or trunk port belonging to an SVI.
A VLAN interface (SVI) is up if ports are forwarding traffic in the associated VLAN. When all ports on a VLAN are down or blocking, the SVI is down. For the SVI line state to be up, at least one port in the VLAN must be up and forwarding. You can use the switchport autostate exclude command to exclude a port from the SVI interface line-state up-or-down calculation. For example, you might exclude a monitoring port from the calculations so that the VLAN is not considered up when only the monitoring port is active.
When you enter the switchport autostate exclude command on a port, the command applies to all VLANs that are enabled on the port.
You can verify the autostate mode of an interface by entering the show interface interface-id switchport privileged EXEC command. If the mode has not been set, the autostate mode does not appear.
Examples
This example shows how to configure autostate exclude on an interface and to verify the configuration:
Related Commands
show interfaces [ interface-id ] switchport |
Displays the administrative and operational status of a switching (nonrouting) port, including autostate mode, if set. |
Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands . |
switchport backup interface
Use the switchport backup interface configuration command on a Layer 2 interface to configure Flex Links, a pair of interfaces that provide backup to each other. Use the no form of this command to remove the Flex Links configuration.
switchport backup interface [FastEthernet interface-id | GigabitEthernet interface-id | Port-channel interface-id | TenGigabitEthernet interface-id] {mmu primary vlan interface-id | multicast fast-convergence | preemption {delay delay-time | mode} | prefer vlan vlan-id}
no switchport backup interface [FastEthernet interface-id | GigabitEthernet interface-id | Port-channel interface-id | TenGigabitEthernet interface-id] {mmu primary vlan interface-id | multicast fast-convergence | preemption {delay delay-time | mode} | prefer vlan vlan-id}
Syntax Description
Command Modes
Usage Guidelines
With Flex Links configured, one link acts as the primary interface and forwards traffic, while the other interface is in standby mode, ready to begin forwarding traffic if the primary link shuts down. The interface being configured is referred to as the active link; the specified interface is identified as the backup link. The feature provides an alternative to the Spanning Tree Protocol (STP), allowing users to turn off STP and still retain basic link redundancy.
- This command is available only for Layer 2 interfaces.
- You can configure only one Flex Link backup link for any active link, and it must be a different interface from the active interface.
- An interface can belong to only one Flex Link pair. An interface can be a backup link for only one active link. An active link cannot belong to another Flex Link pair.
- A backup link does not have to be the same type (Fast Ethernet or Gigabit Ethernet, for instance) as the active link. However, you should configure both Flex Links with similar characteristics so that there are no loops or changes in behavior if the standby link begins to forward traffic.
- Neither of the links can be a port that belongs to an EtherChannel. However, you can configure two port channels (EtherChannel logical interfaces) as Flex Links, and you can configure a port channel and a physical interface as Flex Links, with either the port channel or the physical interface as the active link.
- If STP is configured on the switch, Flex Links do not participate in STP in all valid VLANs. If STP is not running, be sure that there are no loops in the configured topology.
Examples
This example shows how to configure two interfaces as Flex Links:
This example shows how to configure the Fast Ethernet interface to always preempt the backup:
This example shows how to configure the Fast Ethernet interface preemption delay time:
This example shows how to configure the Fast Ethernet interface as the MMU primary VLAN:
The following example shows how to configure preferred VLANs:
You can verify your setting by entering the show interfaces switchport backup privileged EXEC command.
In the following example, VLANs 60, and 100 to 120 are configured on the switch:
When both interfaces are up, Gi1/2 forwards traffic for VLANs 1 to 50, and Gi1/1 forwards traffic for VLANs 60 and 100 to 120.
When a Flex Link interface goes down (LINK_DOWN), VLANs preferred on this interface are moved to the peer interface of the Flex Link pair. In this example, if interface Gi1/2 goes down, Gi1/1 carries all VLANs of the Flex Link pair.
When a Flex Link interface comes up, VLANs preferred on this interface are blocked on the peer interface and moved to the forwarding state on the interface that has just come up. In this example, if interface Gi1/2 comes up, VLANs preferred on this interface are blocked on the peer interface Gi1/1 and forwarded on Gi1/2.
This example shows how to configure multicast fast-convergence on interface Gi1/1:
You can verify your setting by entering the show interfaces switchport backup detail privileged EXEC command.
Related Commands
show interfaces [ interface-id ] switchport backup |
Displays the configured Flex Links and their status on the switch or for the specified interface. |
switchport block
Use the switchport block interface configuration command to prevent unknown multicast or unicast packets from being forwarded. Use the no form of this command to allow forwarding unknown multicast or unicast packets.
switchport block { multicast | unicast }
Command Modes
Usage Guidelines
By default, all traffic with unknown MAC addresses is sent to all ports. You can block unknown multicast or unicast traffic on protected or nonprotected ports. If unknown multicast or unicast traffic is not blocked on a protected port, there could be security issues.
With multicast traffic, the port blocking feature blocks only pure Layer 2 packets. Multicast packets that contain IPv4 or IPv6 information in the header are not blocked.
Blocking unknown multicast or unicast traffic is not automatically enabled on protected ports; you must explicitly configure it.
For more information about blocking packets, see the software configuration guide for this release.
Examples
This example shows how to block unknown unicast traffic on an interface:
You can verify your setting by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces switchport |
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings. |
switchport host
Use the switchport host interface configuration command to optimize a port for a host connection. The no form of this command has no affect on the system.
Command Modes
Usage Guidelines
To optimize the port for a host connection, the switchport host command sets switch port mode to access, enables spanning tree Port Fast, and disables channel grouping. Only an end station can accept this configuration.
Because spanning tree Port Fast is enabled, you should enter the switchport host command only on ports that are connected to a single host. Connecting other switches, hubs, concentrators, or bridges to a fast-start port can cause temporary spanning-tree loops.
Enables the switchport host command to decrease the time that it takes to start up packet forwarding.
Examples
This example shows how to optimize the port configuration for a host connection:
You can verify your setting by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces switchport |
Displays the administrative and operational status of a switching port, including switchport mode. |
switchport mode
Use the switchport mode interface configuration command to configure the VLAN membership mode of a port. Use the no form of this command to reset the mode to the appropriate default for the device.
switchport mode { access | dot1q-tunnel | dynamic { auto | desirable } | private-vlan | trunk }
no switchport mode { access | dot1q-tunnel | dynamic | trunk }
Syntax Description
Set the port to access mode (either static-access or dynamic-access depending on the setting of the switchport access vlan interface configuration command). The port is set to access unconditionally and operates as a nontrunking, single VLAN interface that sends and receives nonencapsulated (non-tagged) frames. An access port can be assigned to only one VLAN. |
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Set the interface trunking mode dynamic parameter to auto to specify that the interface convert the link to a trunk link. This is the default switchport mode. |
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Set the interface trunking mode dynamic parameter to desirable to specify that the interface actively attempt to convert the link to a trunk link. |
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See the switchport mode private-vlan command. |
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Set the port to trunk unconditionally. The port is a trunking VLAN Layer 2 interface. The port sends and receives encapsulated (tagged) frames that identify the VLAN of origination. A trunk is a point-to-point link between two switches or between a switch and a router. |
Command Modes
Usage Guidelines
A configuration that uses the access , dot1q-tunnel , or trunk keywords takes effect only when you configure the port in the appropriate mode by using the switchport mode command. The static-access and trunk configuration are saved, but only one configuration is active at a time.
When you enter access mode, the interface changes to permanent nontrunking mode and negotiates to convert the link into a nontrunk link even if the neighboring interface does not agree to the change.
When you enter trunk mode, the interface changes to permanent trunking mode and negotiates to convert the link into a trunk link even if the interface connecting to it does not agree to the change.
When you enter dynamic auto mode, the interface converts the link to a trunk link if the neighboring interface is set to trunk or desirable mode.
When you enter dynamic desirable mode, the interface becomes a trunk interface if the neighboring interface is set to trunk , desirable , or auto mode.
To autonegotiate trunking, the interfaces must be in the same VLAN Trunking Protocol (VTP) domain. Trunk negotiation is managed by the Dynamic Trunking Protocol ( DTP), which is a point-to-point protocol. However, some internetworking devices might forward DTP frames improperly, which could cause misconfigurations. To avoid this, you should configure interfaces connected to devices that do not support DTP to not forward DTP frames, which turns off DTP.
- If you do not intend to trunk across those links, use the switchport mode a ccess interface configuration command to disable trunking.
- To enable trunking to a device that does not support DTP, use the switchport mode trunk and switchport nonegotiate interface configuration commands to cause the interface to become a trunk but to not generate DTP frames.
When you enter dot1q-tunnel , the port is set unconditionally as an IEEE 802.1Q tunnel port.
Access ports trunk ports, and tunnel ports are mutually exclusive.
Any IEEE 802.1Q encapsulated IP packets received on a tunnel port can be filtered by MAC access control lists (ACLs), but not by IP ACLs. This is because the switch does not recognize the protocol inside the IEEE 802.1Q header. This restriction applies to router ACLs, port ACLs, and VLAN maps.
Configuring a port as an IEEE 802.1Q tunnel port has these limitations:
- IP routing and fallback bridging are not supported on tunnel ports.
- Tunnel ports do not support IP ACLs.
- If an IP ACL is applied to a trunk port in a VLAN that includes tunnel ports, or if a VLAN map is applied to a VLAN that includes tunnel ports, packets received from the tunnel port are treated as non-IP packets and are filtered with MAC access lists.
- Layer 3 quality of service (QoS) ACLs and other QoS features related to Layer 3 information are not supported on tunnel ports.
For more information about configuring IEEE 802.1Q tunnel ports, see the software configuration guide for this release.
The IEEE 802.1x feature interacts with switchport modes in these ways:
- If you try to enable IEEE 802.1x on a trunk port, an error message appears, and IEEE 802.1x is not enabled. If you try to change the mode of an IEEE 802.1x-enabled port to trunk, the port mode is not changed.
- If you try to enable IEEE 802.1x on a port set to dynamic auto or dynamic desirable , an error message appears, and IEEE 802.1x is not enabled. If you try to change the mode of an IEEE 802.1x-enabled port to dynamic auto or dynamic desirable , the port mode is not changed.
- If you try to enable IEEE 802.1x on a dynamic-access (VLAN Query Protocol [VQP]) port, an error message appears, and IEEE 802.1x is not enabled. If you try to change an IEEE 802.1x-enabled port to dynamic VLAN assignment, an error message appears, and the VLAN configuration is not changed.
Examples
This example shows how to configure a port for access mode:
This example shows how set the port to dynamic desirable mode:
This example shows how to configure a port for trunk mode:
This example shows how to configure a port as an IEEE 802.1Q tunnel port:
Related Commands
show interfaces switchport |
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings. |
Configures a port as a static-access or dynamic-access port. |
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Configures the trunk characteristics when an interface is in trunking mode. |
switchport mode private-vlan
Use the switchport mode private-vlan interface configuration command to configure a port as a promiscuous or host private VLAN port. Use the no form of this command to reset the mode to the appropriate default for the device.
switchport mod e private-vlan { host | promiscuous }
no switchport mode private-vlan
Note This command is available only when the switch is running the IP services image.
Syntax Description
Command Modes
Usage Guidelines
A private-VLAN host or promiscuous port cannot be a Switched Port Analyzer (SPAN) destination port. If you configure a SPAN destination port as a private-VLAN host or promiscuous port, the port becomes inactive.
Do not configure private VLAN on ports with these other features:
- Dynamic-access port VLAN membership
- Dynamic Trunking Protocol (DTP)
- Port Aggregation Protocol (PAgP)
- Link Aggregation Control Protocol (LACP)
- Multicast VLAN Registration (MVR)
- Voice VLAN
A private-VLAN port cannot be a SPAN destination port.
While a port is part of the private-VLAN configuration, any EtherChannel configuration for it is inactive.
A private-VLAN port cannot be a secure port and should not be configured as a protected port.
For more information about private-VLAN interaction with other features, see the software configuration guide for this release.
We strongly recommend that you enable spanning tree Port Fast and bridge-protocol-data-unit (BPDU) guard on isolated and community host ports to prevent STP loops due to misconfigurations and to speed up STP convergence.
If you configure a port as a private-VLAN host port and you do not configure a valid private-VLAN association by using the switchport private-vlan host-association interface configuration command, the interface becomes inactive.
If you configure a port as a private-VLAN promiscuous port and you do not configure a valid private VLAN mapping by using the switchport private-vlan mapping interface configuration command, the interface becomes inactive.
Examples
This example shows how to configure an interface as a private-VLAN host port and associate it to primary VLAN 20. The interface is a member of secondary isolated VLAN 501 and primary VLAN 20.
Note When you configure a port as a private VLAN host port, you should also enable BPDU guard and Port Fast by using the spanning-tree portfast bpduguard default global configuration command and the spanning-tree portfast interface configuration command.
This example shows how to configure an interface as a private VLAN promiscuous port and map it to a private VLAN. The interface is a member of primary VLAN 20 and secondary VLANs 501 to 503 are mapped to it.
You can verify private VLAN switchport mode by using the show interfaces interface-id switchport privileged EXEC command.
Related Commands
Configures a VLAN as a community, isolated, or primary VLAN or associates a primary VLAN with secondary VLANs. |
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show interfaces switchport |
Displays the administrative and operational status of a switching (nonrouting) port, including private VLAN configuration. |
Configures private VLAN associations and mappings between primary and secondary VLANs on an interface. |
switchport nonegotiate
Use the switchport nonegotiate interface configuration command to specify that Dynamic Trunking Protocol (DTP) negotiation packets are not sent on the Layer 2 interface. The switch does not engage in DTP negotiation on this interface. Use the no form of this command to return to the default setting.
Command Modes
Usage Guidelines
The no form of the switchport nonegotiate command removes nonegotiate status.
This command is valid only when the interface switchport mode is access or trunk (configured by using the switchport mode access or the switchport mode trunk interface configuration command). This command returns an error if you attempt to execute it in dynamic (auto or desirable) mode.
Internetworking devices that do not support DTP might forward DTP frames improperly and cause misconfigurations. To avoid this, you should turn off DTP by using the switchport no negotiate command to configure the interfaces connected to devices that do not support DTP to not forward DTP frames.
When you enter the switchport nonegotiate command, DTP negotiation packets are not sent on the interface. The device does or does not trunk according to the mode parameter: access or trunk.
- If you do not intend to trunk across those links, use the switchport mode a ccess interface configuration command to disable trunking.
- To enable trunking on a device that does not support DTP, use the switchport mode trunk and switchport nonegotiate interface configuration commands to cause the interface to become a trunk but to not generate DTP frames.
Examples
This example shows how to cause a port to refrain from negotiating trunking mode and to act as a trunk or access port (depending on the mode set):
You can verify your setting by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces switchport |
Displays the administrative and operational status of a switching port, including port blocking and port protection settings. |
switchport port-security
Use the switchport port-security interface configuration command without keywords to enable port security on the interface. Use the keywords to configure secure MAC addresses, sticky MAC address learning, a maximum number of secure MAC addresses, or the violation mode. Use the no form of this command to disable port security or to set the parameters to their default states.
switchport port-security [ mac-address mac-address [ vlan { vlan-id | { access | voice }}] | mac-address sticky [ mac-address | vlan { vlan-id | { access | voice }}]] [ maximum value [ vlan { vlan-list | { access | voice }}]]
no switchport port-security [ mac-address mac-address [ vlan { vlan-id | { access | voice }}] | mac-address sticky [ mac-address | vlan { vlan-id | { access | voice }}]] [ maximum value [ vlan { vlan-list | { access | voice }}]]
switchport port-security [ aging ] [ violation { protect | restrict | shutdown | shutdown vlan}]
no switchport port-security [ aging ] [ violation { protect | restrict | shutdown | shutdown vlan}]
Syntax Description
(Optional) See the switchport port-security aging command. |
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(Optional) Specifies a secure MAC address for the interface by entering a 48-bit MAC address. You can add additional secure MAC addresses up to the maximum value configured. |
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(Optional) On a trunk port only, specify the VLAN ID and the MAC address. If no VLAN ID is specified, the native VLAN is used. |
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(Optional) On an access port only, specify the VLAN as an access VLAN. |
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(Optional) On an access port only, specify the VLAN as a voice VLAN. Note The voice keyword is available only if voice VLAN is configured on a port and if that port is not the access VLAN. |
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(Optional) Enables the interface for sticky learning by entering only the mac-address sticky keywords. When sticky learning is enabled, the interface adds all secure MAC addresses that are dynamically learned to the running configuration and converts these addresses to sticky secure MAC addresses. (Optional) Enter a mac-address to specify a sticky secure MAC address. |
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(Optional) Set the maximum number of secure MAC addresses for the interface.The maximum number of secure MAC addresses that you can configure on a switch is set by the maximum number of available MAC addresses allowed in the system. This number is determined by the active Switch Database Management (SDM) template. For more information, see the sdm prefer global configuration command. This number represents the total of available MAC addresses, including those used for other Layer 2 functions and any other secure MAC addresses configured on interfaces. |
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(Optional) For trunk ports, you can set the maximum number of secure MAC addresses on a VLAN. If the vlan keyword is not entered, the default value is used. |
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(Optional) Set the security violation mode or the action to be taken if port security is violated. The default is shutdown . |
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Set the security violation protect mode. In this mode, when the number of port secure MAC addresses reaches the maximum limit allowed on the port, packets with unknown source addresses are dropped until you remove a sufficient number of secure MAC addresses to drop below the maximum value or increase the number of maximum allowable addresses. You are not notified that a security violation has occurred. Note We do not recommend configuring the protect mode on a trunk port. The protect mode disables learning when any VLAN reaches its maximum limit, even if the port has not reached its maximum limit. |
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Set the security violation restrict mode. In this mode, when the number of secure MAC addresses reaches the limit allowed on the port, packets with unknown source addresses are dropped until you remove a sufficient number of secure MAC addresses or increase the number of maximum allowable addresses. An SNMP trap is sent, a syslog message is logged, and the violation counter increments. |
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Set the security violation shutdown mode. In this mode, the interface is error-disabled when a violation occurs and the port LED turns off. An SNMP trap is sent, a syslog message is logged, and the violation counter increments. When a secure port is in the error-disabled state, you can bring it out of this state by entering the errdisable recovery cause psecure-violation global configuration command, or you can manually re-enable it by entering the shutdown and no shut down interface configuration commands. |
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Set the security violation mode to per-VLAN shutdown. In this mode, only the VLAN on which the violation occurred is error-disabled. |
Command Modes
Usage Guidelines
A secure port has the following limitations:
- A secure port can be an access port or a trunk port; it cannot be a dynamic access port.
- A secure port cannot be a routed port.
- A secure port cannot be a protected port.
- A secure port cannot be a destination port for Switched Port Analyzer (SPAN).
- A secure port cannot be a private VLAN port.
- A secure port cannot belong to a Fast EtherChannel or Gigabit EtherChannel port group.
- You cannot configure static secure or sticky secure MAC addresses in the voice VLAN.
- When you enable port security on an interface that is also configured with a voice VLAN, set the maximum allowed secure addresses on the port to two. When the port is connected to a Cisco IP phone, the IP phone requires one MAC address. The Cisco IP phone address is learned on the voice VLAN, but is not learned on the access VLAN. If you connect a single PC to the Cisco IP phone, no additional MAC addresses are required. If you connect more than one PC to the Cisco IP phone, you must configure enough secure addresses to allow one for each PC and one for the Cisco IP phone.
- Voice VLAN is supported only on access ports and not on trunk ports.
- When you enter a maximum secure address value for an interface, if the new value is greater than the previous value, the new value overrides the previously configured value. If the new value is less than the previous value and the number of configured secure addresses on the interface exceeds the new value, the command is rejected.
- The switch does not support port security aging of sticky secure MAC addresses.
A security violation occurs when the maximum number of secure MAC addresses are in the address table and a station whose MAC address is not in the address table attempts to access the interface or when a station whose MAC address is configured as a secure MAC address on another secure port attempts to access the interface.
When a secure port is in the error-disabled state, you can bring it out of this state by entering the errdisable recovery cause psecure-violation global configuration command. You can manually re-enable the port by entering the shutdown and no shut down interface configuration commands or by using the clear errdisable interface privileged EXEC command.
Setting a maximum number of addresses to one and configuring the MAC address of an attached device ensures that the device has the full bandwidth of the port.
When you enter a maximum secure address value for an interface, this occurs:
- If the new value is greater than the previous value, the new value overrides the previously configured value.
- If the new value is less than the previous value and the number of configured secure addresses on the interface exceeds the new value, the command is rejected.
Sticky secure MAC addresses have these characteristics:
- When you enable sticky learning on an interface by using the switchport port-security mac-address sticky interface configuration command, the interface converts all the dynamic secure MAC addresses, including those that were dynamically learned before sticky learning was enabled, to sticky secure MAC addresses and adds all sticky secure MAC addresses to the running configuration.
- If you disable sticky learning by using the no switchport port-security mac-address sticky interface configuration command or the running configuration is removed, the sticky secure MAC addresses remain part of the running configuration but are removed from the address table. The addresses that were removed can be dynamically reconfigured and added to the address table as dynamic addresses.
- When you configure sticky secure MAC addresses by using the switchport port-security mac-address sticky mac-address interface configuration command, these addresses are added to the address table and the running configuration. If port security is disabled, the sticky secure MAC addresses remain in the running configuration.
- If you save the sticky secure MAC addresses in the configuration file, when the switch restarts or the interface shuts down, the interface does not need to relearn these addresses. If you do not save the sticky secure addresses, they are lost. If sticky learning is disabled, the sticky secure MAC addresses are converted to dynamic secure addresses and are removed from the running configuration.
- If you disable sticky learning and enter the switchport port-security mac-address sticky mac-address interface configuration command, an error message appears, and the sticky secure MAC address is not added to the running configuration.
Examples
This example shows how to enable port security on a port and to set the maximum number of secure addresses to 5. The violation mode is the default, and no secure MAC addresses are configured.
This example shows how to configure a secure MAC address and a VLAN ID on a port:
This example shows how to enable sticky learning and to enter two sticky secure MAC addresses on a port:
This example show how to configure a port to shut down only the VLAN if a violation occurs:
You can verify your settings by using the show port-security privileged EXEC command.
Related Commands
Deletes from the MAC address table a specific type of secure address or all the secure addresses on the switch or an interface. |
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show port-security address |
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show port-security |
Displays port security configuration for the switch or for the specified interface. |
switchport port-security aging
Use the switchport port-security aging interface configuration command to set the aging time and type for secure address entries or to change the aging behavior for secure addresses on a particular port. Use the no form of this command to disable port security aging or to set the parameters to their default states.
switchport port-security aging { static | time time | type { absolute | inactivity }}
no switchport port-security aging { static | time | type }
Syntax Description
Command Modes
Usage Guidelines
To enable secure address aging for a particular port, set the aging time to a value other than 0 for that port.
To allow limited time access to particular secure addresses, set the aging type as absolute . When the aging time lapses, the secure addresses are deleted.
To allow continuous access to a limited number of secure addresses, set the aging type as inactivity . This removes the secure address when it become inactive, and other addresses can become secure.
To allow unlimited access to a secure address, configure it as a secure address, and disable aging for the statically configured secure address by using the no switchport port-security aging static interface configuration command.
Examples
This example sets the aging time as 2 hours for absolute aging for all the secure addresses on the port:
This example sets the aging time as 2 minutes for inactivity aging type with aging enabled for configured secure addresses on the port:
This example shows how to disable aging for configured secure addresses:
switchport priority extend
Use the switchport priority extend interface configuration command to set a port priority for the incoming untagged frames or the priority of frames received by the IP phone connected to the specified port. Use the no form of this command to return to the default setting.
switchport priority extend { cos value | trust }
Syntax Description
Command Modes
Usage Guidelines
When voice VLAN is enabled, you can configure the switch to send the Cisco Discovery Protocol (CDP) packets to instruct the IP phone how to send data packets from the device attached to the access port on the Cisco IP Phone. You must enable CDP on the switch port connected to the Cisco IP Phone to send the configuration to the Cisco IP Phone. (CDP is enabled by default globally and on all switch interfaces.)
You should configure voice VLAN on switch access ports. You can configure a voice VLAN only on Layer 2 ports.
Before you enable voice VLAN, we recommend that you enable quality of service (QoS) on the switch by entering the mls qos global configuration command and configure the port trust state to trust by entering the mls qos trust cos interface configuration command.
Examples
This example shows how to configure the IP phone connected to the specified port to trust the received IEEE 802.1p priority:
You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command.
switchport private-vlan
Use the switchport private-vlan interface configuration command to define a private-VLAN association for an isolated or community port or a mapping for a promiscuous port. Use the no form of this command to remove the private-VLAN association or mapping from the port.
switchport private-vlan { association { host primary-vlan-id secondary-vlan-id | mapping primary-vlan-id { add | remove } secondary-vlan-list } | host-association primary-vlan-id secondary-vlan-id | mapping primary-vlan-id { add | remove } secondary-vlan-list }
no switchport private-vlan { association { host | mapping } | host-association | mapping
Note This command is available only when the switch is running the IP services image.
Syntax Description
Command Modes
Usage Guidelines
Private-VLAN association or mapping has no effect on the port unless the port has been configured as a private-VLAN host or promiscuous port by using the switchport mod e private-vlan { host | promiscuous } interface configuration command.
If the port is in private-VLAN host or promiscuous mode but the VLANs do not exist, the command is allowed, but the port is made inactive.
The secondary_vlan_list parameter cannot contain spaces. It can contain multiple comma-separated items. Each item can be a single private-VLAN ID or a hyphenated range of private-VLAN IDs. The list can contain one isolated VLAN and multiple community VLANs.
You can map a promiscuous port to only one primary VLAN. If you enter the switchport private-vlan mapping command on a promiscuous port that is already mapped to a primary and secondary VLAN, the primary VLAN mapping is overwritten.
You can add or remove secondary VLANs from promiscuous port private-VLAN mappings by using the add and remove keywords.
Entering the switchport private-vlan association host command has the same effect as entering the switchport private-vlan host-association interface configuration command.
Entering the switchport private-vlan association mapping command has the same effect as entering the switchport private-vlan mapping interface configuration command.
Examples
This example shows how to configure an interface as a private VLAN host port and associate it with primary VLAN 20 and secondary VLAN 501:
This example shows how to configure an interface as a private-VLAN promiscuous port and map it to a primary VLAN and secondary VLANs:
You can verify private-VLAN mapping by using the show interfaces private-vlan mapping privileged EXEC command. You can verify private VLANs and interfaces configured on the switch by using the show vlan private-vlan privileged EXEC command.
Related Commands
show interfaces private-vlan mapping |
|
show vlan private-vlan |
Displays all private VLAN relationships or types configured on the switch. |
switchport protected
Use the switch port protected interface configuration command to isolate unicast, multicast, and broadcast traffic at Layer 2 from other protected ports on the same switch. Use the no form of this command to disable protection on the port.
Command Modes
Usage Guidelines
The switchport protection feature is local to the switch; communication between protected ports on the same switch is possible only through a Layer 3 device. To prevent communication between protected ports on different switches, you must configure the protected ports for unique VLANs on each switch and configure a trunk link between the switches. A protected port is different from a secure port.
A protected port does not forward any traffic (unicast, multicast, or broadcast) to any other port that is also a protected port. Data traffic cannot be forwarded between protected ports at Layer 2; only control traffic, such as PIM packets, is forwarded because these packets are processed by the CPU and forwarded in software. All data traffic passing between protected ports must be forwarded through a Layer 3 device.
Port monitoring does not work if both the monitor and monitored ports are protected ports.
Examples
This example shows how to enable a protected port on an interface:
You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command.
Syntax Description
show interfaces switchport |
Displays the administrative and operational status of a switching port, including port blocking and port protection settings. |
Prevents unknown multicast or unicast traffic on the interface. |
switchport trunk
Use the switchport trunk interface configuration command to set the trunk characteristics when the interface is in trunking mode. Use the no form of this command to reset a trunking characteristic to the default.
switchport trunk { allowed vlan vlan-list | native vlan vlan-id | pruning vlan vlan-list }
no switchport trunk { allowed vlan | native vlan | { pruning vlan }
Syntax Description
The vlan-list format is all | none | [ add | remove | except ] vlan-atom [ , vlan-atom... ] where:
- all specifies all VLANs from 1 to 4094. This keyword is not allowed on commands that do not permit all VLANs in the list to be set at the same time.
- none means an empty list. This keyword is not allowed on commands that require certain VLANs to be set or at least one VLAN to be set.
- add adds the defined list of VLANs to those currently set instead of replacing the list. Valid IDs are from 1 to 1005; extended-range VLANs (VLAN IDs greater than 1005) are valid in some cases.
Note You can add extended-range VLANs to the allowed VLAN list, but not to the pruning-eligible VLAN list.
Separate nonconsecutive VLAN IDs with a comma; use a hyphen to designate a range of IDs.
- remove removes the defined list of VLANs from those currently set instead of replacing the list. Valid IDs are from 1 to 1005; extended-range VLAN IDs are valid in some cases.
Note You can remove extended-range VLANs from the allowed VLAN list, but you cannot remove them from the pruning-eligible list.
Separate nonconsecutive VLAN IDs with a comma; use a hyphen to designate a range of IDs.
- except lists the VLANs that should be calculated by inverting the defined list of VLANs. (VLANs are added except the ones specified.) Valid IDs are from 1 to 1005. Separate nonconsecutive VLAN IDs with a comma; use a hyphen to designate a range of IDs.
- vlan-atom is either a single VLAN number from 1 to 4094 or a continuous range of VLANs described by two VLAN numbers, the lesser one first, separated by a hyphen.
Command Modes
Usage Guidelines
- All untagged traffic received on an IEEE 802.1Q trunk port is forwarded with the native VLAN configured for the port.
- If a packet has a VLAN ID that is the same as the sending-port native VLAN ID, the packet is sent without a tag; otherwise, the switch sends the packet with a tag.
- The no form of the native vlan command res ets the native mode VLAN to the appropriate default VLAN for the device.
- To reduce the risk of spanning-tree loops or storms, you can disable VLAN 1 on any individual VLAN trunk port by removing VLAN 1 from the allowed list. When you remove VLAN 1 from a trunk port, the interface continues to send and receive management traffic, for example, Cisco Discovery Protocol (CDP), Port Aggregation Protocol (PAgP), Link Aggregation Control Protocol (LACP), Dynamic Trunking Protocol (DTP), and VLAN Trunking Protocol (VTP) in VLAN 1.
- The no form of the allowed vlan command resets the list to the default list, which allows all VLANs.
- The pruning-eligible list applies only to trunk ports.
- Each trunk port has its own eligibility list.
- If you do not want a VLAN to be pruned, remove it from the pruning-eligible list. VLANs that are pruning-ineligible receive flooded traffic.
- VLAN 1, VLANs 1002 to 1005, and extended-range VLANs (VLANs 1006 to 4094) cannot be pruned.
Examples
This example shows how to configure VLAN 3 as the default for the port to send all untagged traffic:
This example shows how to add VLANs 1, 2, 5, and 6 to the allowed list:
This example shows how to remove VLANs 3 and 10 to 15 from the pruning-eligible list:
You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces switchport |
Displays the administrative and operational status of a switching (nonrouting) port, including port blocking and port protection settings. |
switchport voice vlan
Use the switchport voice vlan interface configuration command to configure voice VLAN on the port. Use the no form of this command to return to the default setting.
switchport voice vlan { vlan-id | dot1p | none | untagged }
Syntax Description
Command Modes
Usage Guidelines
You should configure voice VLAN on Layer 2 access ports.
You must enable Cisco Discovery Protocol (CDP) on the switchport connected to the Cisco IP phone for the switch to send configuration information to the phone. CDP is enabled by default globally and on the interface.
Before you enable voice VLAN, we recommend that you enable quality of service (QoS) on the switch by entering the mls qos global configuration command and configure the port trust state to trust by entering the mls qos trust cos interface configuration command.
When you enter a VLAN ID, the IP phone forwards voice traffic in IEEE 802.1Q frames, tagged with the specified VLAN ID. The switch puts IEEE 802.1Q voice traffic in the voice VLAN.
When you select dot1q , none , or untagged , the switch puts the indicated voice traffic in the access VLAN.
In all configurations, the voice traffic carries a Layer 2 IP precedence value. The default is 5 for voice traffic.
When you enable port security on an interface that is also configured with a voice VLAN, set the maximum allowed secure addresses on the port to two. When the port is connected to a Cisco IP phone, the IP phone requires one MAC address. The Cisco IP phone address is learned on the voice VLAN, but is not learned on the access VLAN. If you connect a single PC to the Cisco IP phone, no additional MAC addresses are required. If you connect more than one PC to the Cisco IP phone, you must configure enough secure addresses to allow one for each PC and one for the Cisco IP phone.
If any type of port security is enabled on the access VLAN, dynamic port security is automatically enabled on the voice VLAN.
You cannot configure static secure MAC addresses in the voice VLAN.
A voice-VLAN port cannot be a private-VLAN port.
The Port Fast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the Port Fast feature is not automatically disabled.
Examples
This example shows how to configure VLAN 2 as the voice VLAN for the port:
You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC command.
Related Commands
show interfaces interface-id switchport |
Displays the administrative and operational status of a switching (nonrouting) port. |
Decides how the device connected to the specified port handles priority traffic received on its incoming port. |
system mtu
Use the system mtu global configuration command to set the maximum packet size or maximum transmission unit (MTU) size for Gigabit Ethernet ports, for routed ports, or for Fast Ethernet (10/100) ports. Use the no form of this command to restore the global MTU value to its default value.
system mtu { bytes | jumbo bytes | routing bytes }
Syntax Description
Command Modes
Usage Guidelines
When you use this command to change the system MTU or jumbo MTU size, you must reset the switch before the new configuration takes effect.The system mtu routing command does not require a switch reset to take effect.
The system MTU setting is saved in the switch environmental variable in NVRAM and becomes effective when the switch reloads. Unlike the system MTU routing configuration, the MTU settings you enter with the system mtu and system mtu jumbo commands are not saved in the switch IOS configuration file, even if you enter the copy running-config startup-config privileged EXEC command. Therefore, if you use TFTP to configure a new switch by using a backup configuration file and want the system MTU to be other than the default, you must explicitly configure the system mtu and system mtu jumbo settings on the new switch and then reload the switch.
Gigabit Ethernet ports operating at 1000 Mb/s are not affected by the system mtu command, and 10/100-Mb/s ports are not affected by the system mtu jumbo command.
You can use the system mtu routing command to configure the MTU size on routed ports.
Note You cannot configure a routing MTU size that exceeds the system MTU size. If you change the system MTU size to a value smaller than the currently configured routing MTU size, the configuration change is accepted, but not applied until the next switch reset. When the configuration change takes effect, the routing MTU size defaults to the new system MTU size.
If you enter a value that is outside the range for the specific type of switch, the value is not accepted.
Note The switch does not support setting the MTU on a per-interface basis.
The size of frames that can be received by the switch CPU is limited to 1998 bytes, regardless of the value entered with the system mtu command. Although forwarded or routed frames are usually not received by the CPU, some packets (for example, control traffic, SNMP, Telnet, and routing protocols) are sent to the CPU.
Because the switch does not fragment packets, it drops:
- switched packets larger than the packet size supported on the egress interface
- routed packets larger than the routing MTU value
For example, if the system mtu value is 1998 bytes and the system mtu jumbo value is 5000 bytes, packets up to 5000 bytes can be received on interfaces operating at 1000 Mb/s. However, although a packet larger than 1998 bytes can be received on an interface operating at 1000 Mb/s, if its destination interface is operating at 10 or 100 Mb/s, the packet is dropped.
Examples
This example shows how to set the maximum jumbo packet size for Gigabit Ethernet ports operating at 1000 Mb/s or greater to 1800 bytes:
You can verify your setting by entering the show system mtu privileged EXEC command.
test cable-diagnostics tdr
Use the test cable-diagnostics tdr privileged EXEC command to run the Time Domain Reflector (TDR) feature on an interface.
Command Modes
Usage Guidelines
TDR is supported only on 10/100 and 10/100/1000 copper Ethernet ports. It is not supported on SFP module ports. For more information about TDR, see the software configuration guide for this release.
After you run TDR by using the test cable-diagnostics tdr interface interface-id command, use the show cable-diagnostics tdr interface interface-id privileged EXEC command to display the results.
Examples
This example shows how to run TDR on an interface:
If you enter the test cable-diagnostics tdr interface interface-id command on an interface that has a link status of up and a speed of 10 or 100 Mb/s, these messages appear:
test relay
Use the test relay privileged EXEC command to turn on or off the relay circuitry.
test relay { major | minor } { on | off }
Command Modes
Usage Guidelines
You can use the test relay privileged EXEC command to verify relay circuitry connections to the alert devices. You can test alarm scanners without having to create an alarm condition.
traceroute mac
Use the traceroute mac privileged EXEC command to display the Layer 2 path taken by the packets from the specified source MAC address to the specified destination MAC address.
traceroute mac [ interface interface-id ] { source-mac-address } [ interface interface-id ] { destination-mac-address } [ vlan vlan-id ] [ detail ]
Syntax Description
Command Modes
Usage Guidelines
For Layer 2 traceroute to function properly, Cisco Discovery Protocol (CDP) must be enabled on all the switches in the network. Do not disable CDP.
When the switch detects a device in the Layer 2 path that does not support Layer 2 traceroute, the switch continues to send Layer 2 trace queries and lets them time out.
The maximum number of hops identified in the path is ten.
Layer 2 traceroute supports only unicast traffic. If you specify a multicast source or destination MAC address, the physical path is not identified, and an error message appears.
The traceroute mac command output shows the Layer 2 path when the specified source and destination addresses belong to the same VLAN. If you specify source and destination addresses that belong to different VLANs, the Layer 2 path is not identified, and an error message appears.
If the source or destination MAC address belongs to multiple VLANs, you must specify the VLAN to which both the source and destination MAC addresses belong. If the VLAN is not specified, the path is not identified, and an error message appears.
The Layer 2 traceroute feature is not supported when multiple devices are attached to one port through hubs (for example, multiple CDP neighbors are detected on a port). When more than one CDP neighbor is detected on a port, the Layer 2 path is not identified, and an error message appears.
Examples
This example shows how to display the Layer 2 path by specifying the source and destination MAC addresses:
This example shows how to display the Layer 2 path by using the detail keyword:
This example shows how to display the Layer 2 path by specifying the interfaces on the source and destination switches:
This example shows the Layer 2 path when the switch is not connected to the source switch:
This example shows the Layer 2 path when the switch cannot find the destination port for the source MAC address:
This example shows the Layer 2 path when the source and destination devices are in different VLANs:
This example shows the Layer 2 path when the destination MAC address is a multicast address:
This example shows the Layer 2 path when source and destination switches belong to multiple VLANs:
traceroute mac ip
Use the traceroute mac ip privileged EXEC command to display the Layer 2 path taken by the packets from the specified source IP address or hostname to the specified destination IP address or hostname.
traceroute mac ip { source-ip-address | source-hostname } { destination-ip-address | destination-hostname } [ detail ]
Command Modes
Usage Guidelines
For Layer 2 traceroute to function properly, Cisco Discovery Protocol (CDP) must be enabled on all the switches in the network. Do not disable CDP.
When the switch detects an device in the Layer 2 path that does not support Layer 2 traceroute, the switch continues to send Layer 2 trace queries and lets them time out.
The maximum number of hops identified in the path is ten.
The traceroute mac ip command output shows the Layer 2 path when the specified source and destination IP addresses are in the same subnet. When you specify the IP addresses, the switch uses Address Resolution Protocol (ARP) to associate the IP addresses with the corresponding MAC addresses and the VLAN IDs.
- If an ARP entry exists for the specified IP address, the switch uses the associated MAC address and identifies the physical path.
- If an ARP entry does not exist, the switch sends an ARP query and tries to resolve the IP address. The IP addresses must be in the same subnet. If the IP address is not resolved, the path is not identified, and an error message appears.
The Layer 2 traceroute feature is not supported when multiple devices are attached to one port through hubs (for example, multiple CDP neighbors are detected on a port). When more than one CDP neighbor is detected on a port, the Layer 2 path is not identified, and an error message appears.
Examples
This example shows how to display the Layer 2 path by specifying the source and destination IP addresses and by using the detail keyword:
This example shows how to display the Layer 2 path by specifying the source and destination hostnames:
This example shows the Layer 2 path when ARP cannot associate the source IP address with the corresponding MAC address:
trust
Use the trust policy-map class configuration command to define a trust state for traffic classified through the class policy-map configuration or the class-map global configuration command. Use the no form of this command to return to the default setting.
trust [ cos | dscp | ip-precedence ]
no trust [ cos | dscp | ip-precedence ]
Syntax Description
Command Modes
Policy-map class configuration
Usage Guidelines
Use this command to distinguish the quality of service (QoS) trust behavior for certain traffic from other traffic. For example, incoming traffic with certain DSCP values can be trusted. You can configure a class map to match and trust the DSCP values in the incoming traffic.
Trust values set with this command supersede trust values set with the mls qos trust interface configuration command.
The trust command is mutually exclusive with set policy-map class configuration command within the same policy map.
If you specify trust cos , QoS uses the received or default port CoS value and the CoS-to-DSCP map to generate a DSCP value for the packet.
If you specify trust dscp , QoS uses the DSCP value from the ingress packet. For non-IP packets that are tagged, QoS uses the received CoS value; for non-IP packets that are untagged, QoS uses the default port CoS value. In either case, the DSCP value for the packet is derived from the CoS-to-DSCP map.
If you specify trust ip-precedence , QoS uses the IP precedence value from the ingress packet and the IP-precedence-to-DSCP map. For non-IP packets that are tagged, QoS uses the received CoS value; for non-IP packets that are untagged, QoS uses the default port CoS value. In either case, the DSCP for the packet is derived from the CoS-to-DSCP map.
To return to policy-map configuration mode, use the exit command. To return to privileged EXEC mode, use the end command.
Examples
This example shows how to define a port trust state to trust incoming DSCP values for traffic classified with class1 :
You can verify your settings by entering the show policy-map privileged EXEC command.
Related Commands
udld
Use the udld global configuration command to enable aggressive or normal mode in the UniDirectional Link Detection (UDLD) and to set the configurable message timer time. Use the no form of the command to disable aggressive or normal mode UDLD on all fiber-optic ports.
udld { aggressive | enable | message time message-timer-interval }
Command Modes
Usage Guidelines
UDLD supports two modes of operation: normal (the default) and aggressive. In normal mode, UDLD detects unidirectional links due to misconnected interfaces on fiber-optic connections. In aggressive mode, UDLD also detects unidirectional links due to one-way traffic on fiber-optic and twisted-pair links and due to misconnected interfaces on fiber-optic links. For information about normal and aggressive modes, see the “Understanding UDLD” section in the software configuration guide for this release.
If you change the message time between probe packets, you are making a trade-off between the detection speed and the CPU load. By decreasing the time, you can make the detection-response faster but increase the load on the CPU.
This command affects fiber-optic interfaces only. Use the udld interface configuration command to enable UDLD on other interface types.
You can use these commands to reset an interface shut down by UDLD:
- The udld reset privileged EXEC command to reset all interfaces shut down by UDLD
- The shutdown and no shutdown interface configuration commands
- The no udld enable global configuration command followed by the udld { aggressive | enable } global configuration command to re-enable UDLD globally
- The no udld port interface configuration command followed by the udld port or udld port aggressive interface configuration command to re-enable UDLD on the specified interface
- The errdisable recovery cause udld and errdisable recovery interval interval global configuration commands to automatically recover from the UDLD error-disabled state
Examples
This example shows how to enable UDLD on all fiber-optic interfaces:
You can verify your setting by entering the show udld privileged EXEC command .
Related Commands
udld port
Use the udld port interface configuration command to enable the UniDirectional Link Detection (UDLD) on an individual interface or prevent a fiber-optic interface from being enabled by the udld global configuration command. Use the no form of this command to return to the udld global configuration command setting or to disable UDLD if entered for a nonfiber-optic port.
Command Modes
Usage Guidelines
A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of another switch.
UDLD supports two modes of operation: normal (the default) and aggressive. In normal mode, UDLD detects unidirectional links due to misconnected interfaces on fiber-optic connections. In aggressive mode, UDLD also detects unidirectional links due to one-way traffic on fiber-optic and twisted-pair links and due to misconnected interfaces on fiber-optic links. For information about normal and aggressive modes, see the “Configuring UDLD” chapter in the software configuration guide for this release.
To enable UDLD in normal mode, use the udld port interface configuration command. To enable UDLD in aggressive mode, use the udld port aggressive interface configuration command.
Use the no udld port command on fiber-optic ports to return control of UDLD to the udld enable global configuration command or to disable UDLD on nonfiber-optic ports.
Use the udld port aggressive command on fiber-optic ports to override the setting of the udld enable or udld aggressive global configuration command. Use the no form on fiber-optic ports to remove this setting and to return control of UDLD enabling to the udld global configuration command or to disable UDLD on nonfiber-optic ports.
You can use these commands to reset an interface shut down by UDLD:
- The udld reset privileged EXEC command to reset all interfaces shut down by UDLD
- The shutdown and no shutdown interface configuration commands
- The no udld enable global configuration command followed by the udld { aggressive | enable } global configuration command to re-enable UDLD globally
- The no udld port interface configuration command followed by the udld port or udld port aggressive interface configuration command to re-enable UDLD on the specified interface
- The errdisable recovery cause udld and errdisable recovery interval interval global configuration commands to automatically recover from the UDLD error-disabled state
Examples
This example shows how to enable UDLD on an port:
This example shows how to disable UDLD on a fiber-optic interface despite the setting of the udld global configuration command:
You can verify your settings by entering the show running-config or the show udld interface privileged EXEC command.
Related Commands
udld reset
Use the udld reset privileged EXEC command to reset all interfaces disabled by the UniDirectional Link Detection (UDLD) and permit traffic to begin passing through them again (though other features, such as spanning tree, Port Aggregation Protocol (PAgP), and Dynamic Trunking Protocol (DTP) still have their normal effects, if enabled).
Command Modes
Usage Guidelines
If the interface configuration is still enabled for UDLD, these ports begin to run UDLD again and are disabled for the same reason if the problem has not been corrected.
Examples
This example shows how to reset all interfaces disabled by UDLD:
You can verify your setting by entering the show udld privileged EXEC command.
Related Commands
vlan
Use the vlan global configuration command to add a VLAN and to enter the VLAN configuration mode. Use the no form of this command to delete the VLAN. Configuration information for normal-range VLANs (VLAN IDs 1 to 1005) is always saved in the VLAN database. When you are using (VLAN Trunking Protocol (VTP) version 3 or when VTP mode is transparent (VTP version 1 or 2), you can create extended-range VLANs (VLAN IDs greater than 1005). In VTP version 3, these VLANs are also saved in the VLAN database.
Command Modes
Usage Guidelines
You use the vlan vlan-id global configuration command to add normal-range VLANs (VLAN IDs 1 t0 1005) or extended-range VLANs (VLAN IDs 1006 to 4094). With VTP version 1 and version 2, before adding extended-range VLANs, you must use the vtp transparent global configuration command to put the switch in VTP transparent mode. With VTP version 1 and 2, extended-range VLANs are not learned by VTP and are not added to the VLAN database. When VTP mode is transparent, VTP mode and domain name and all VLAN configurations are saved in the running configuration, and you can save them in the switch startup configuration file.
VTP version 3 supports propagation of extended-range VLANs and you can create them in VTP server or client mode.
When you save the VLAN and VTP configurations in the startup configuration file and reboot the switch, the configuration is selected in these ways:
- If both the VLAN database and the configuration file show the VTP mode as transparent and the VTP domain names match, the VLAN database is ignored. The VTP and VLAN configurations in the startup configuration file are used. The VLAN database revision number remains unchanged in the VLAN database.
- If the VTP mode is server, or if the startup VTP mode or domain names do not match the VLAN database, the VTP mode and the VLAN configuration for the first 1005 VLANs use the VLAN database information. With VTP version 3, all VLAN-IDs are in the VLAN database.
With VTP version 1 and version 2, if you try to create an extended-range VLAN when the switch is not in VTP transparent mode, the VLAN is rejected, and you receive an error message.
If you enter an invalid VLAN ID, you receive an error message and do not enter config-vlan mode.
Entering the vlan command with a VLAN ID enables config-vlan mode. When you enter the VLAN ID of an existing VLAN, you do not create a new VLAN, but you can modify VLAN parameters for that VLAN. The specified VLANs are added or modified when you exit the config-vlan mode. Only the shutdown command (for VLANs 1 to 1005) takes effect immediately.
These configuration commands are available in config-vlan mode. The no form of each command returns the characteristic to its default state.
Note Although all commands are visible, the only VLAN configuration commands that are supported on extended-range VLANs are mtu mtu-size and remote-span. For extended-range VLANs, all other characteristics must remain at the default state.
- are are-number : defines the maximum number of all-routes explorer (ARE) hops for this VLAN. This keyword applies only to TrCRF VLANs.The range is 0 to 13. The default is 7. If no value is entered, 0 is assumed to be the maximum.
- backupcrf : specifies the backup CRF mode. This keyword applies only to TrCRF VLANs.
– enable backup CRF mode for this VLAN.
– disable backup CRF mode for this VLAN (the default).
- bridge { bridge-number| type }: specifies the logical distributed source-routing bridge, the bridge that interconnects all logical rings having this VLAN as a parent VLAN in FDDI-NET, Token Ring-NET, and TrBRF VLANs. The range is 0 to 15. The default bridge number is 0 (no source-routing bridge) for FDDI-NET, TrBRF, and Token Ring-NET VLANs. The type keyword applies only to TrCRF VLANs and is one of these:
– srt (source-route transparent) bridging VLAN
- exit : applies changes, increments the VLAN database revision number (VLANs 1 to 1005 only), and exits config-vlan mode.
- media : defines the VLAN media type. See Table 2-39 for valid commands and syntax for different media types.
Note The switch supports only Ethernet ports. You configure only FDDI and Token Ring media-specific characteristics for VLAN Trunking Protocol (VTP) global advertisements to other switches. These VLANs are locally suspended.
– ethernet is Ethernet media type (the default).
– fd-net is FDDI network entity title (NET) media type.
– tokenring is Token Ring media type if the VTP v2 mode is disabled, or TrCRF if the VTP Version 2 (v) mode is enabled.
– tr-net is Token Ring network entity title (NET) media type if the VTP v2 mode is disabled or TrBRF media type if the VTP v2 mode is enabled.
- mtu mtu-size : specifies the maximum transmission unit (MTU) (packet size in bytes). The range is 1500 to 18190. The default is 1500 bytes.
- name vlan-name : names the VLAN with an ASCII string from 1 to 32 characters that must be unique within the administrative domain. The default is VLANxxxx where xxxx represents four numeric digits (including leading zeros) equal to the VLAN ID number.
- no : negates a command or returns it to the default setting.
- parent parent-vlan-id : specifies the parent VLAN of an existing FDDI, Token Ring, or TrCRF VLAN. This parameter identifies the TrBRF to which a TrCRF belongs and is required when defining a TrCRF. The range is 0 to 1005. The default parent VLAN ID is 0 (no parent VLAN) for FDDI and Token Ring VLANs. For both Token Ring and TrCRF VLANs, the parent VLAN ID must already exist in the database and be associated with a Token Ring-NET or TrBRF VLAN.
- private-vlan : configure the VLAN as a private VLAN community, isolated, or primary VLAN or configure the association between private-VLAN primary and secondary VLANs. For more information, see the private-vlan command.
- remote-span : configure the VLAN as a Remote SPAN (RSPAN) VLAN. When the RSPAN feature is added to an existing VLAN, the VLAN is first deleted and is then recreated with the RSPAN feature. Any access ports are deactivated until the RSPAN feature is removed. If VTP is enabled, the new RSPAN VLAN is propagated by VTP for VLAN-IDs that are lower than 1024. Learning is disabled on the VLAN. See the remote-span command for more information.
- ring ring-number : defines the logical ring for an FDDI, Token Ring, or TrCRF VLAN. The range is 1 to 4095. The default for Token Ring VLANs is 0. For FDDI VLANs, there is no default.
- said said-value : specifies the security association identifier (SAID) as documented in IEEE 802.10. The range is 1 to 4294967294, and the number must be unique within the administrative domain. The default value is 100000 plus the VLAN ID number.
- shutdown : shuts down VLAN switching on the VLAN. This command takes effect immediately. Other commands take effect when you exit config-vlan mode.
- state : specifies the VLAN state:
– active means the VLAN is operational (the default).
– suspend means the VLAN is suspended. Suspended VLANs do not pass packets.
- ste ste-number : defines the maximum number of spanning-tree explorer (STE) hops. This keyword applies only to TrCRF VLANs. The range is 0 to 13. The default is 7.
- stp type : defines the spanning-tree type for FDDI-NET, Token Ring-NET, or TrBRF VLANs. For FDDI-NET VLANs, the default STP type is ieee . For Token Ring-NET VLANs, the default STP type is ibm . For FDDI and Token Ring VLANs, the default is no type specified.
– ieee for IEEE Ethernet STP running source-route transparent (SRT) bridging.
– ibm for IBM STP running source-route bridging (SRB).
– auto for STP running a combination of source-route transparent bridging (IEEE) and source-route bridging (IBM).
- tb-vlan1 tb-vlan1-id and tb-vlan2 tb-vlan2-id : specifies the first and second VLAN to which this VLAN is translationally bridged. Translational VLANs translate FDDI or Token Ring to Ethernet, for example. The range is 0 to 1005. If no value is specified, 0 (no transitional bridging) is assumed.
Table 2-40 describes the rules for configuring VLANs.
Examples
This example shows how to add an Ethernet VLAN with default media characteristics. The default includes a vlan-name of VLANxxx , where xxxx represents four numeric digits (including leading zeros) equal to the VLAN ID number. The default media option is ethernet ; the state option is active . The default said-value variable is 100000 plus the VLAN ID; the mtu-size variable is 1500; the stp-type option is ieee . When you enter the exit config-vlan configuration command, the VLAN is added if it did not already exist; otherwise, this command does nothing.
This example shows how to create a new VLAN with all default characteristics and enter config-vlan mode:
This example shows how to create a new extended-range VLAN with all the default characteristics, to enter config-vlan mode, and to save the new VLAN in the switch startup configuration file:
You can verify your setting by entering the show vlan privileged EXEC command.
vlan access-map
Use the vlan access-map global configuration command to create or modify a VLAN map entry for VLAN packet filtering. This entry changes the mode to the VLAN access-map configuration. Use the no form of this command to delete a VLAN map entry. Use the vlan filter interface configuration command to apply a VLAN map to one or more VLANs.
vlan access-map name [ number ]
no vlan access-map name [ number ]
Syntax Description
Command Modes
Usage Guidelines
In global configuration mode, use this command to create or modify a VLAN map. This entry changes the mode to VLAN access-map configuration, where you can use the match access-map configuration command to specify the access lists for IP or non-IP traffic to match and use the action command to set whether a match causes the packet to be forwarded or dropped.
In VLAN access-map configuration mode, these commands are available:
- action : sets the action to be taken (forward or drop).
- default : sets a command to its defaults
- exit : exits from VLAN access-map configuration mode
- match : sets the values to match (IP address or MAC address).
- no : negates a command or set its defaults
When you do not specify an entry number (sequence number), it is added to the end of the map.
There can be only one VLAN map per VLAN and it is applied as packets are received by a VLAN.
You can use the no vlan access-map name [ number ] command with a sequence number to delete a single entry.
In global configuration mode, use the vlan filter interface configuration command to apply the map to one or more VLANs.
For more information about VLAN map entries, see the software configuration guide for this release.
Examples
This example shows how to create a VLAN map named vac1 and apply matching conditions and actions to it. If no other entries already exist in the map, this will be entry 10.
vlan dot1q tag native
Use the vlan dot1q tag native global configuration command to enable tagging of native VLAN frames on all IEEE 802.1Q trunk ports. Use the no form of this command to return to the default setting.
Note This command is available only when the switch is running the IP services image.
Command Modes
Usage Guidelines
When enabled, native VLAN packets going out all IEEE 802.1Q trunk ports are tagged.
When disabled, native VLAN packets going out all IEEE 802.1Q trunk ports are not tagged.
You can use this command with the IEEE 802.1Q tunneling feature. This feature operates on an edge switch of a service-provider network and expands VLAN space by using a VLAN-in-VLAN hierarchy and tagging the tagged packets. You must use IEEE 802.1Q trunk ports for sending packets to the service-provider network. However, packets going through the core of the service-provider network might also be carried on IEEE 802.1Q trunks. If the native VLANs of an IEEE 802.1Q trunks match the native VLAN of a tunneling port on the same switch, traffic on the native VLAN is not tagged on the sending trunk port. This command ensures that native VLAN packets on all IEEE 802.1Q trunk ports are tagged.
For more information about IEEE 802.1Q tunneling, see the software configuration guide for this release.
Examples
This example shows how to enable IEEE 802.1Q tagging on native VLAN frames:
You can verify your settings by entering the show vlan dot1q tag native privileged EXEC command.
Related Commands
show vlan dot1q tag native |
vlan filter
Use the vlan filter global configuration command to apply a VLAN map to one or more VLANs. Use the no form of this command to remove the map.
vlan filter mapname vlan-list { list | all }
no vlan filter mapname vlan-list { list | all }
Note This command is available only when the switch is running the IP services image.
Command Modes
Usage Guidelines
To avoid accidentally dropping too many packets and disabling connectivity in the middle of the configuration process, we recommend that you completely define the VLAN access map before applying it to a VLAN.
For more information about VLAN map entries, see the software configuration guide for this release.
Examples
This example applies VLAN map entry map1 to VLANs 20 and 30:
This example shows how to delete VLAN map entry mac1 from VLAN 20:
You can verify your settings by entering the show vlan filter privileged EXEC command.
vmps reconfirm (privileged EXEC)
Use the vmps reconfirm privileged EXEC command to immediately send VLAN Query Protocol (VQP) queries to reconfirm all dynamic VLAN assignments with the VLAN Membership Policy Server (VMPS).
Command Modes
Examples
This example shows how to immediately send VQP queries to the VMPS:
You can verify your setting by entering the show vmps privileged EXEC command and examining the VMPS Action row of the Reconfirmation Status section. The show vmps command shows the result of the last time the assignments were reconfirmed either because the reconfirmation timer expired or because the vmps reconfirm command was entered.
vmps reconfirm (global configuration)
Use the vmps reconfirm global configuration command to change the reconfirmation interval for the VLAN Query Protocol (VQP) client. Use the no form of this command to return to the default setting.
Command Modes
Examples
This example shows how to set the VQP client to reconfirm dynamic VLAN entries every 20 minutes:
You can verify your setting by entering the show vmps privileged EXEC command and examining information in the Reconfirm Interval row.
vmps retry
Use the vmps retry global configuration command to configure the per-server retry count for the VLAN Query Protocol (VQP) client. Use the no form of this command to return to the default setting.
Command Modes
Examples
This example shows how to set the retry count to 7:
You can verify your setting by entering the show vmps privileged EXEC command and examining information in the Server Retry Count row.
vmps server
Use the vmps server global configuration command to configure the primary VLAN Membership Policy Server (VMPS) and up to three secondary servers. Use the no form of this command to remove a VMPS server.
Command Modes
Usage Guidelines
The first server entered is automatically selected as the primary server whether or not primary is entered. The first server address can be overridden by using primary in a subsequent command.
If a member switch in a cluster configuration does not have an IP address, the cluster does not use the VMPS server configured for that member switch. Instead, the cluster uses the VMPS server on the command switch, and the command switch proxies the VMPS requests. The VMPS server treats the cluster as a single switch and uses the IP address of the command switch to respond to requests.
When using the no form without specifying the ipaddress , all configured servers are deleted. If you delete all servers when dynamic-access ports are present, the switch cannot forward packets from new sources on these ports because it cannot query the VMPS.
Examples
This example shows how to configure the server with IP address 191.10.49.20 as the primary VMPS server. The servers with IP addresses 191.10.49.21 and 191.10.49.22 are configured as secondary servers:
This example shows how to delete the server with IP address 191.10.49.21:
You can verify your setting by entering the show vmps privileged EXEC command and examining information in the VMPS Domain Server row.
vtp (global configuration)
Use the vtp global configuration command to set or modify the VLAN Trunking Protocol (VTP) configuration characteristics. Use the no form of this command to remove the settings or to return to the default settings.
vtp { domain domain-name | file filename | interface name [ only ] | mode { client | off | server | transparent } [ mst | unknown | vlan ] | password password [ hidden | secret ] | pruning | version number }
no vtp { file | interface | mode [ client | off | server | transparent ] [ mst | unknown | vlan ] | password | pruning | version }
Syntax Description
Command Modes
Usage Guidelines
When you save VTP mode, domain name, and VLAN configurations in the switch startup configuration file and reboot the switch, the VTP and VLAN configurations are selected by these conditions:
- If both the VLAN database and the configuration file show the VTP mode as transparent and the VTP domain names match, the VLAN database is ignored. The VTP and VLAN configurations in the startup configuration file are used. The VLAN database revision number remains unchanged in the VLAN database.
- If the startup VTP mode is server mode, or the startup VTP mode or domain names do not match the VLAN database, VTP mode and VLAN configuration for the first 1005 VLANs are selected by VLAN database information, and VLANs greater than 1005 are configured from the switch configuration file.
The vtp file filename cannot be used to load a new database; it renames only the file in which the existing database is stored.
Follow these guidelines when configuring a VTP domain name:
- The switch is in the no-management-domain state until you configure a domain name. While in the no-management-domain state, the switch does not send any VTP advertisements even if changes occur to the local VLAN configuration. The switch leaves the no-management-domain state after it receives the first VTP summary packet on any port that is trunking or after you configure a domain name by using the vtp domain command. If the switch receives its domain from a summary packet, it resets its configuration revision number to 0. After the switch leaves the no-management-domain state, it can no be configured to re-enter it until you clear the NVRAM and reload the software.
- Domain names are case-sensitive.
- After you configure a domain name, it cannot be removed. You can only reassign it to a different domain.
Follow these guidelines when setting VTP mode:
- The no vtp mode command returns the switch to VTP server mode.
- The vtp mode server command is the same as no vtp mode except that it does not return an error if the switch is not in client or transparent mode.
- If the receiving switch is in client mode, the client switch changes its configuration to duplicate the configuration of the server. If you have switches in client mode, be sure to make all VTP or VLAN configuration changes on a switch in server mode. If the receiving switch is in server mode or transparent mode, the switch configuration is not changed.
- Switches in transparent mode do not participate in VTP. If you make VTP or VLAN configuration changes on a switch in transparent mode, the changes are not propagated to other switches in the network.
- If you change the VTP or VLAN configuration on a switch that is in server mode, that change is propagated to all the switches in the same VTP domain.
- The vtp mode transparent command disables VTP from the domain but does not remove the domain from the switch.
- In VTP versions 1 and 2, the VTP mode must be transparent for you to add extended-range VLANs or for VTP and VLAN information to be saved in the running configuration file. VTP supports extended-range VLANs in client and server mode and saved them in the VLAN database.
- With VTP versions 1 and 2, if extended-range VLANs are configured on the switch and you attempt to set the VTP mode to server or client, you receive an error message, and the configuration is not allowed. Changing VTP mode is allowed with extended VLANs in VTP version 3.
- VTP can be set to either server or client mode only when dynamic VLAN creation is disabled.
- The vtp mode off command sets the device to off. The no vtp mode off command resets the device to the VTP server mode.
Follow these guidelines when setting a VTP password:
- Passwords are case sensitive. Passwords should match on all switches in the same domain.
- When you use the no vtp password form of the command, the switch returns to the no-password state.
- The hidden and secret keywords are supported only in VTP version 3. If you convert from VTP version 2 to VTP version 3, you must remove the hidden or secret keyword before the conversion.
Follow these guidelines when setting VTP pruning:
- VTP pruning removes information about each pruning-eligible VLAN from VTP updates if there are no stations belonging to that VLAN.
- If you enable pruning on the VTP server, it is enabled for the entire management domain for VLAN IDs 1 to 1005.
- Only VLANs in the pruning-eligible list can be pruned.
- Pruning is supported with VTP Version 1 and Version 2.
Follow these guidelines when setting the VTP version:
- Toggling the Version 2 (v2) mode state modifies parameters of certain default VLANs.
- Each VTP switch automatically detects the capabilities of all the other VTP devices. To use Version 2, all VTP switches in the network must support Version 2; otherwise, you must configure them to operate in VTP Version 1 mode.
- If all switches in a domain are VTP Version 2-capable, you need only to configure Version 2 on one switch; the version number is then propagated to the other Version-2 capable switches in the VTP domain.
- If you are using VTP in a Token Ring environment, VTP Version 2 must be enabled.
- If you are configuring a Token Ring bridge relay function (TrBRF) or Token Ring concentrator relay function (TrCRF) VLAN media type, you must use Version 2.
- If you are configuring a Token Ring or Token Ring-NET VLAN media type, you must use Version 1.
- In VTP version 3, all database VTP information is propagated across the VTP domain, not only VLAN database information.
- Two VTP version 3 regions can only communicate over a VTP version 1 or VTP version 2 region in transparent mode.
You cannot save password, pruning, and version configurations in the switch configuration file.
Examples
This example shows how to rename the filename for VTP configuration storage to vtpfilename :
This example shows how to clear the device storage filename:
This example shows how to specify the name of the interface providing the VTP updater ID for this device:
This example shows how to set the administrative domain for the switch:
This example shows how to place the switch in VTP transparent mode:
This example shows how to configure the VTP domain password:
This example shows how to enable pruning in the VLAN database:
This example shows how to enable Version 2 mode in the VLAN database:
You can verify your settings by entering the show vtp status privileged EXEC command.
Related Commands
show vtp status |
Displays the VTP statistics for the switch and general information about the VTP management domain status. |
vtp (interface configuration)
Use the vtp interface configuration command to enable the VLAN Trunking Protocol (VTP) on a per-port basis. Use the no form of this command to disable VTP on the interface.
Note This command is supported only when the switch is running the LAN base image and VTP version 3.
Command Modes
Usage Guidelines
Enter this command only interfaces that are switchport in trunk mode.
This command is supported only on switches configured for VTP version 3.
Examples
This example shows how to enable VTP on an interface:
vtp primary
Use the vtp primary privileged EXEC command to configure a switch as the VLAN Trunking Protocol (VTP) primary server.
vtp primary [ mst | vlan ] [ force ]
There is no no form of the command.
Note This command is supported only when the switch is running the LAN base image and VTP version 3.
Note Although visible in the command line help, the vtp {password password | pruning | version number} commands are not supported.
Command Modes
Usage Guidelines
This command is supported only on switches configured for VTP version 3.
A VTP primary server updates the database information and sends updates that are honored by all devices in the system. A VTP secondary server can only back up the updated VTP configurations received from the primary server to NVRAM.
By default, all devices come up as secondary servers. Primary server status is needed only for database updates when the administrator issues a takeover message in the domain. You can have a working VTP domain without any primary servers.
Primary server status is lost if the device reloads or domain parameters change.
Examples
This example shows how to configure the switch as the primary VTP server for VLANs:
You can verify your settings by entering the show vtp status privileged EXEC command.
Related Commands
show vtp status |
Displays the VTP statistics for the switch and general information about the VTP management domain status. |
Configures the VTP filename, interface, domain name, mode, and version. |