F Commands

feature adapter-fex

To enable the Adapter Fabric Extender (Adapter-FEX), use the feature adapter-fex command. To disable Adapter-FEX, use the no form of this command.

feature adapter-fex

no feature adapter-fex

Syntax Description

This command has no arguments or keywords.

Command Default

Disabled

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

Before you disable this feature on the switch, do the following:

  • Remove all virtual Ethernet interface configurations on the switch.

  • Remove all port profiles of type vethernet.

  • Change the port mode to access by using the switchport mode access command.

If you attempt to disable the Adapter-FEX feature with virtual Ethernet interface or port profile configurations enabled, the switch returns an error message.

Before you use a virtual Ethernet interface, you must enable Cisco Virtual Machine Fabric Extender (VM-FEX) on the switch by using the feature vmfex command.

Examples

This example shows how to enable Adapter-FEX on the switch: 


switch# configure terminal
switch(config)# feature adapter-fex
Virtualization Plugin license checked out successfully
Virtualization Plugin extracted successfully
All Virtualization processes enabled successfully
switch(config)#

This example shows how to disable Adapter-FEX on the switch: 


switch# configure terminal
switch(config)# no feature adapter-fex
Disabled feature adapter-fex successfully.
You should save the configuration and Reload.
switch(config)#

This example shows the error message that appears when you attempt to disable Adapter-FEX on a switch with virtual Ethernet interface configurations enabled: 


switch# configure terminal
switch(config)# no feature adapter-fex
Disabling of NIV failed.veth and vntag configs found
Shutdown all veths and Remove them.
Change ports with 'switchport mode vntag' to 'switchport mode access'.
switch(config)#

Related Commands

Command

Description

interface vethernet

Configures a virtual Ethernet interface.

port-profile

Configures a port profile.

show feature

Displays whether or not Adapter-FEX is enabled on the switch.

switchport mode

Configures the interface as a nontrunking nontagged single-VLAN Ethernet interface.

feature interface-vlan

To enable the creation of VLAN interfaces, use the feature interface-vlan command. To disable the VLAN interface feature, use the no form of this command.

feature interface-vlan

no feature interface-vlan

Syntax Description

This command has no arguments or keywords.

Command Default

VLAN interfaces are disabled.

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

You must use the feature interface-vlan or the svi enable command before you can create VLAN interfaces.

Examples

This example shows how to enable the interface VLAN feature on the switch: 


switch(config)# feature interface-vlan

Related Commands

Command

Description

interface vlan

Creates a VLAN interface.

show feature

Displays the features that are enabled or disabled on the switch.

feature lacp

To enable the Link Aggregation Control Protocol (LACP), which bundles a number of physical ports together to form a single logical channel, use the feature lacp command. To disable LACP on the switch, use the no form of this command.

feature lacp

no feature lacp

Syntax Description

This command has no arguments or keywords.

Command Default

LACP is disabled.

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

You must remove all the LACP configuration parameters from all EtherChannels on the switch before you can disable LACP.

Even after you enable LACP globally, you do not have to run LACP on all EtherChannels on the switch. You enable LACP on each channel mode using the channel-group mode command.

Examples

This example shows how to enable LACP EtherChannels on the switch: 


switch(config)# feature lacp

Related Commands

Command

Description

show lacp

Displays information on LACP.

show feature

Displays whether or not LACP is enabled on the switch.

feature lldp

The Link Layer Discovery Protocol (LLDP), which is a neighbor discovery protocol that is used for network devices to advertise information about themselves to other devices on the network, is enabled on the switch by default.

feature lldp

no feature lldp

Syntax Description

This command has no arguments or keywords.

Command Default

Enabled

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

You cannot enable or disable LLDP on a Cisco Nexus device. LLDP is enabled on the switch by default. However, the feature lldp command shows as part of the running configuration on the switch, as shown below: 


switch# show running-config
 
!Command: show running-config
!Time: Wed Jan 30 12:36:03 2013
version 6.02N1(1)
feature telnet
feature lldp
username admin password 5 $1$d8lkfqC8$4VfRuOoZTKvCtTq8VAKbq/  role network-admin
no password strength-check
ip domain-lookup
hostname switch
class-map type qos class-fcoe
class-map type qos match-all c1
  match cos 1
<--Output truncated-->
switch#

The Cisco Discovery Protocol (CDP) is a device discovery protocol that runs over Layer 2 (the data link layer) on all Cisco-manufactured devices (routers, bridges, access servers, and switches). CDP allows network management applications to automatically discover and learn about other Cisco devices connected to the network.

To support non-Cisco devices and to allow for interoperability between other devices, the switch supports the Link Layer Discovery Protocol (LLDP). LLDP is a neighbor discovery protocol that is used for network devices to advertise information about themselves to other devices on the network. This protocol runs over the data-link layer, which allows two systems running different network layer protocols to learn about each other.

Examples

This example shows how to enable LLDP on the switch: 


switch(config)# feature lldp
switch(config)#

This example shows how to disable LLDP on the switch: 


switch(config)# no feature lldp
switch(config)#

Related Commands

Command

Description

lldp

Configures the global LLDP options on the switch.

lldp (Interface)

Configures the LLDP feature on an interface.

show feature

Displays that LLDP is enabled on the switch.

feature poe

To enable Power over Ethernet (PoE), use the feature poe command. To disable PoE, use the no form of this command.

feature poe

no feature poe

Syntax Description

This command has no keywords or arguments.

Command Default

Disabled

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Examples

This example shows how to enable PoE on the switch: 


switch(config)# feature poe

Related Commands

Command

Description

power inline

Configures the power usage for interfaces.

show feature

Displays the status of features enabled or disabled on the switch.

feature port-security

To enable port security on Layer 2 interfaces, use the feature port-security command. To disable port security, use the no form of this command.

feature port-security

no feature port-security

Syntax Description

This command has no keywords or arguments.

Command Default

Disabled

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

Use the port security feature to secure a port by limiting and identifying the MAC addresses of the switches that are allowed to access the port.

You can enable port security on a virtual port channel (vPC) port only if the following occurs:

  • Port security is enabled on both the vPC peers

  • Port security is enabled on the vPC port on both the vPC peers

This command does not require a license.

Examples

This example shows how to enable PoE on the switch: 


switch(config)# feature poe

Related Commands

Command

Description

power inline

Configures the power usage for interfaces.

show feature

Displays the status of features enabled or disabled on the switch.

feature private-vlan

To enable private VLANs, use the feature private-vlan command. To return to the default settings, use the no form of this command.

feature private-vlan

no feature private-vlan

Syntax Description

This command has no arguments or keywords.

Command Default

Private VLANs are disabled.

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

The private VLAN commands are not available until you enable the private VLAN feature.

You cannot disable the private VLANs if there are operational ports on the switch that are in private VLAN mode.


Note
A private VLAN-isolated port on a Cisco Nexus device running the current release of Cisco NX-OS does not support IEEE 802.1Q encapsulation and cannot be used as a trunk port.

Examples

This example shows how to enable private VLAN functionality on the switch: 


switch(config)# feature private-vlan

Related Commands

Command

Description

private-vlan

Configures a VLAN as either a community, isolated, or primary private VLAN.

show vlan private-vlan

Displays information on private VLANs. If the feature is not enabled, this command is not available.

show feature

Displays whether or not private VLAN is enabled on the switch.

feature ptp

To enable the Precision Time Protocol (PTP) feature, use the feature ptp command. To disable the PTP feature, use the no form of this command.

feature ptp

no feature ptp

Syntax Description

This command has no arguments or keywords.

Command Default

Disabled

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

This command does not require a license.

Examples

This example shows how to enable the PTP feature: 


switch# configure terminal
switch(config)# feature ptp
switch(config)#

This example shows how to disable the PTP feature: 


switch# configure terminal
switch(config)# no feature ptp
switch(config)#

Related Commands

Command

Description

ptp source

Configures the source IP address for all PTP packets.

ptp domain

Configures the domain number to use for this clock.

ptp priority1

Configures the priority1 value to use when advertising this clock.

ptp priority2

Configures the priority2 value to use when advertising this clock.

show ptp brief

Displays the PTP status.

show ptp clock

Displays the properties of the local clock.

feature udld

To enable the Cisco-proprietary Unidirectional Link Detection (UDLD) protocol, which allows ports that are connected through fiber optics or copper Ethernet cables to monitor the physical configuration of the cables and detect when a unidirectional link exists, use the feature udld command. To disable UDLD on the switch, use the no form of this command.

feature udld

no feature udld

Syntax Description

This command has no arguments or keywords.

Command Default

UDLD is disabled.

Command Modes

Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Examples

This example shows how to enable the UDLD on the switch: 


switch# feature udld

Related Commands

Command

Description

show udld

Displays the administrative and operational UDLD status.

show feature

Displays whether or not UDLD is enabled on the switch.

feature vmfex

To enable the Cisco Virtual Machine Fabric Extender (VM-FEX), use the feature vmfex command. To disable VM-FEX, use the no form of this command.

feature vmfex

no feature vmfex

Syntax Description

This command has no arguments or keywords.

Command Default

Disabled

Command Modes


Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Usage Guidelines

Before you use this command, make sure that you install and enable the virtualization feature set using the install feature-set virtualization and feature-set virtualization commands respectively.

If you attempt to disable the VM-FEX feature with virtual Ethernet interface or port profile configurations enabled, the switch returns an error message.

This command requires an Enhanced Layer 2 license.

Examples

This example shows how to enable VM-FEX on the switch: 


switch# configure terminal
switch(config)# feature vmfex
switch(config)#

This example shows how to disable VM-FEX on the switch: 


switch# configure terminal
switch(config)# no feature vmfex
switch(config)#

Related Commands

Command

Description

feature-set virtualization

Enables the virtualization features.

interface vethernet

Configures a virtual Ethernet interface.

install feature-set virtualization

Installs the virtualization feature set on the switch.

port-profile

Configures a port profile.

show feature

Displays the features that are enabled or disabled on the switch.

show feature-set

Displays the status of the virtualization feature set.

switchport mode

Configures the interface as a nontrunking nontagged single-VLAN Ethernet interface.

feature vtp

To enable VLAN Trunking Protocol (VTP), use the feature vtp command. To disable VTP, use the no form of this command.

feature vtp

no feature vtp

Syntax Description

This command has no arguments or keywords.

Command Default

Disabled

Command Modes


Global configuration mode

Command History

Release

Modification

7.0(1)N1(1)

This command was introduced.

Examples

This example shows how to enable VTP on the switch: 


switch(config)# feature vtp

Related Commands

Command

Description

show vtp status

Displays the VTP information.

vtp

Configures VTP.