Configuring Virtual Ethernet Interfaces

This chapter contains the following sections:

Information About vEthernet Interfaces

Virtual Ethernet (vEthernet or vEth) interfaces are logical interfaces. Each vEthernet interface corresponds to a switch interface that is connected to a virtual port. The interface types are as follows:

  • VM (interfaces connected to VM NICs)
  • Service console
  • vmkernel

vEthernet interfaces are created on the Cisco Nexus 1000V to represent virtual ports in use on the distributed virtual switch.

vEthernet interfaces are mapped to connected ports by MAC address as well as DVPort number. When a server administrator changes the port profile assignment on a vNIC or hypervisor port, the same vEthernet interface is reused.

When bringing up a vEthernet interface where a change in the port profile assignment is detected, the Virtual Supervisor Module (VSM) automatically purges any manual configuration present on the interface. You can use the following command to prevent purging of the manual configuration:

no svs veth auto-config-purge

Guidelines and Limitations

vEthernet interface configuration has the following configuration guideline and limitation:

MTU cannot be configured on a vEthernet interface.

Default Settings

Table 1 Default Settings for vEthernet Interface
Parameters Default

Switchport mode

Access

Allowed VLANs

1 to 4094

Access VLAN ID

VLAN1

Native VLAN ID

VLAN1

Native VLAN ID tagging

Disabled

Administrative state

Shut

Automatic deletion of vEthernet interfaces

Enabled

Automatic purge of manual configuration on vEthernet interfaces

Enabled

Automatic creation of vEthernet interfaces

Enabled

Configuring vEthernet Interfaces

Configuring Global vEthernet Properties

You can enable or disable the following automatic controls for vEthernet interfaces:

  • Deleting unused vEthernet interfaces
  • Purging of manual vEthernet configurations
  • Creating vEthernet interfaces
Before You Begin

Log in to the CLI in EXEC mode.

Procedure
      Command or Action Purpose
    Step 1 switch# configure terminal 

    Enters global configuration mode.

     
    Step 2 switch(config)# [no] svs veth auto-delete  (Optional)

    Enables the VSM to automatically delete DVPorts no longer used by a vNIC or hypervisor port.

    The default setting is enabled.

    The no form of this command prevents the VSM from deleting unused DVPorts.

     
    Step 3 switch(config)# [no] svs veth auto-config-purge  (Optional)

    Enables the VSM to remove all manual configuration on a vEthernet interface when the system administrator changes a port profile on the interface.

    The default setting is enabled.

    The no form of this command prevents the manual configuration from being deleted in this situation.

    Note   

    Port profiles with ephemeral bindings are purged regardless of this setting.
     
    Step 4 switch(config)# [no] svs veth auto-setup  (Optional)

    Enables the VSM to automatically create a vEthernet interface when a new port is activated on a host.

    The no form of this command disables the automatic creation of vEthernet interfaces in this situation.

    Note   

    You can use no form of the command to temporary block automatic creation of vEthernet interfaces.
     
    Step 5 switch(config)# show running-config all | grep “svs-veth”  (Optional)

    Displays the default global vEthernet settings that are in effect on the VSM for verification. If a setting is disabled, it does not display in the show command output.

     
    Step 6 switch(config)# copy running-config startup-config  (Optional)

    Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

     

    This example shows how to configure global vEthernet properties:

    switch# configure terminal 
switch(config)# svs veth auto-delete
switch(config)# svs veth auto-config-purge
switch(config)# svs veth auto-setup
switch(config)# show running-config all | grep "svs veth"
svs veth auto-setup                                                             
svs veth auto-delete                                                            
svs veth auto-config-purge
switch(config-if)#

    Configuring a vEthernet Access Interface

    You can configure a vEthernet interface for use as an access interface.

    Before You Begin
    • Log in to the CLI in EXEC mode.
    • If you do not add a description to the vEthernet interface, one of the following descriptions is added at attach time. If you add a description and then remove it using the no description command, then one of the following descriptions is added to the interface:
      • For a VM—VM-Name, Network Adapter number
      • For a VMK—VMware VMkernel, vmk number
      • For a VSWIF—VMware Service Console, vswif number
    Procedure
        Command or Action Purpose
      Step 1 switch# configure terminal 

      Enters global configuration mode.

       
      Step 2 switch(config)# interface vethernet interface-number   (Optional)

      Enters the interface configuration mode for the specified vEthernet interface (from 1 to 1048575).

       
      Step 3 switch(config-if)# description string   (Optional)

      Adds a description of up to 80 alphanumeric characters to the interface in the running configuration.

      Note   

      If you do not add a description, the default description is added.
      Note   

      You do not need to use quotations around descriptions that include spaces.
       
      Step 4 switch(config-if)# switchport access vlan vlanid  

      Configures the vEthernet interface as an access interface and specifies the VLAN ID (1 to 4094) in the running configuration.

       
      Step 5 switch(config-if)# switchport mode access 

      Configures the vEthernet interface for use as an access interface in the running configuration.

       
      Step 6 switch(config-if)# show interface vethernet interface-number  (Optional)

      Displays the specified interface for verification.

       
      Step 7 switch(config-if)# copy running-config startup-config  (Optional)

      Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

       

      This example shows how to configure a vEthernet access interface:

      switch# configure terminal 
switch(config)# interface vethernet 100
switch(config-if)# description accessvlan
switch(config-if)# switchport access vlan 5
switch(config-if)# switchport mode access
switch(config-if)# show interface vethernet1
switch(config-if)#

      Configuring a Private VLAN on a vEthernet Interface

      You can configure a private VLAN (PVLAN) on a vEthernet interface.

      Before You Begin

      Log in to the CLI in EXEC mode.

      Procedure
          Command or Action Purpose
        Step 1 switch# configure terminal 

        Enters global configuration mode.

         
        Step 2 switch(config)# interface vethernet interface-number  

        Enters the interface configuration mode for the specified vEthernet interface (from 1 to 1048575).

         
        Step 3 switch(config-if)# description string   (Optional)

        Adds a description of up to 80 alphanumeric characters to the interface in the running configuration.

        Note   

        If you do not add a description, the default description is added.
        Note   

        You do not need to use quotations around descriptions that include spaces.
         
        Step 4 switch(config-if)# switchport access vlan vlanid  

        Configures the vEthernet interface as an access interface and specifies the VLAN ID (1 to 4094) in the running configuration.

         
        Step 5 switch(config-if)# switchport mode private-vlan host 

        Configures the vEthernet interface for a PVLAN host in the running configuration.

         
        Step 6 switch(config-if)# switchport private-vlan host-association primary-vlanid 

        Configures the vEthernet interface for a host association with a specific primary VLAN ID (from 1 to 4094) in the running configuration.

         
        Step 7 switch(config-if)# show interface   (Optional)

        Displays the interface status and information.

         
        Step 8 switch(config-if)# copy running-config startup-config  (Optional)

        Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

         

        This example shows how to configure a vEthernet interface to use in a PVLAN:

        switch# configure terminal 
switch(config)# interface vethernet 1
switch(config-if)# switchport access vlan 5
switch(config-if)# switchport mode private-vlan host
switch(config-if)# switchport private-vlan host-association 5
switch(config-if)# show interface vethernet 1
Vethernet1 is up
Port description is gentoo, Network Adapter 1
Hardware is Virtual, address is 0050.5687.3bac
Owner is VM "gentoo", adapter is Network Adapter 1
Active on module 4
VMware DVS port 1
Port-Profile is vm
Port mode is access
5 minute input rate 1 bytes/second, 0 packets/second
5 minute output rate 94 bytes/second, 1 packets/second
Rx
655 Input Packets 594 Unicast Packets
0 Multicast Packets 61 Broadcast Packets
114988 Bytes
Tx
98875 Output Packets 1759 Unicast Packets
80410 Multicast Packets 16706 Broadcast Packets 0 Flood Packets
6368452 Bytes
0 Input Packet Drops 0 Output Packet Drops
switch(config-if)#

        Enabling or Disabling a vEthernet Interface

        You can enable or disable a vEthernet interface.

        Before You Begin

        Log in to the CLI in EXEC mode.

        Procedure
            Command or Action Purpose
          Step 1 switch# configure terminal 

          Enters global configuration mode.

           
          Step 2 switch(config)# interface vethernet interface-number  

          Enters the interface configuration mode for the specified vEthernet interface (from 1 to 1048575).

           
          Step 3 switch(config-if)# [no] shutdown 

          Enables or disables the vEthernet interface in the running configuration:

          • shutdown: Disables the vEthernet interface.
          • no shutdown: Enables the vEthernet interface.
           
          Step 4 switch(config-if)# show interface   (Optional)

          Displays the interface status and information.

           
          Step 5 switch(config-if)# copy running-config startup-config  (Optional)

          Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

           

          This example shows how to enable a vEthernet interface:

          switch# configure terminal 
switch(config)# interface vethernet 100
switch(config-if)# no shutdown
switch(config-if)# how interface veth100 status
--------------------------------------------------------------------------------
Port           Name               Status   Vlan      Duplex  Speed   Type
--------------------------------------------------------------------------------
Veth100        --                       up          1       auto        auto    --
switch(config-if)#

          Verifying the vEthernet Interface Configuration

          Use one of the following commands to verify the configuration:

          Command Purpose

          show interface vethernet interface-number [brief | counters [detailed [all] | errors] | description | mac-address | status [ down | err-disabled | inactive | module num | up ] | switchport]

          Displays the vEthernet interface configuration.

          show interface [vethernet interface-number]

          Displays the complete interface configuration.

          show interface [vethernet interface-number] brief

          Displays the abbreviated interface configuration.

          show interface [vethernet interface-number] description

          Displays the interface description.

          show interface [vethernet interface-number] mac-address

          Displays the interface MAC address.

          Note   

          For vEth interfaces, this command shows the MAC address of the connected device.

          show interface [vethernet interface-number] status [down | err-disabled | inactive | module num | up]

          Displays the interface line status.

          show interface [vethernet interface-number] switchport

          Displays interface switchport information.

          show interface virtual [vm [vm_name] | vmk | vswif] [module mod_no]

          Displays virtual interfaces only.

          show interface virtual port-mapping [vm [name] | vmk | vswif | description] [module_num]

          Displays mappings between the virtual ethernet and VMware DVPort.

          Example: show interface vethernet

          The following example shows how to display vEthernet 1:

          switch# show interface veth1
Vethernet1 is up
    Port description is gentoo1, Network Adapter 1
    Hardware is Virtual, address is 0050.56bd.42f6
    Owner is VM "gentoo1", adapter is Network Adapter 1
    Active on module 33
    VMware DVS port 100
    Port-Profile is vlan48
    Port mode is access
    Rx
    491242 Input Packets 491180 Unicast Packets
    7 Multicast Packets 55 Broadcast Packets
    29488527 Bytes
    Tx
    504958 Output Packets 491181 Unicast Packets
    1 Multicast Packets 13776 Broadcast Packets 941 Flood Packets
    714925076 Bytes
    11 Input Packet Drops 0 Output Packet Drops
switch#

          Example: show interface virtual

          The following example shows how to display information for all vEthernet interfaces:

          switch# show interface virtual
--------------------------------------------------------------------------------
Port        Adapter        Owner                    Mod Host
--------------------------------------------------------------------------------
Veth1                      Vm1-kl61                 2                           
Veth2                      VM1-kl65                 5                           
Veth3                      VM2-kl61                 2                           
Veth1       Net Adapter 1  austen-gentoo1          33  austen-strider.austen.
Veth2       Net Adapter 2  austen-gentoo1          33  austen-strider.austen.
switch#

          Example: show interface virtual description

          The following example shows how to display the descriptions for all vEthernet interfaces:

          switch# show interface virtual description
--------------------------------------------------------------------------------
Interface   Description                                                         
--------------------------------------------------------------------------------
Veth1       gentoo1, Network Adapter 1                                  
Veth2       gentoo1, Network Adapter 2                                  
Veth3       VMware VMkernel, vmk1                                               
Veth4       VMware Service Console, vswif1   

switch#

          Example: show interface virtual port-mapping

          The following example shows how to display the virtual port mapping for all vEthernet interfaces:

          switch# show interface virtual port-mapping
-------------------------------------------------------------------------------
Port    Hypervisor Port    Binding Type    Status    Reason 
-------------------------------------------------------------------------------
Veth1   DVPort5747         static          up        none
Veth2   DVPort3361         static          up        none
switch#

          Example: show running-config interface veth1

          The following example shows how to display the running configuration information for all vEthernet interfaces:

          switch# show running-config interface veth1
version 4.2(1)SV1(4)
 
interface Vethernet1
  inherit port-profile vlan48
  description gentoo1, Network Adapter 1
  vmware dvport 2968 dvswitch uuid "d4 02 20 50 16 4b 36 97-46 09 dc d8 5b c6 1e c1"
  vmware vm mac 0050.56A0.0000
      
switch#

          Monitoring the vEthernet Interface Configuration

          Use one of the following commands to monitor the vEthernet interface configuration:

          Command Purpose

          show interface [vethernet interface-number] counters

          Displays the interface incoming and outgoing counters.

          show interface [ vethernet interface-number] counters detailed [all]

          Displays detailed information for all counters.

          Note   

          If all is not specified, only nonzero counters are shown.

          show interface [vethernet interface-number] counters errors

          Displays the interface error counters.

          The following example shows how to display the counters for all vEthernet interfaces:

          switch# show interface counters

--------------------------------------------------------------------------------
Port              InOctets   InUcastPkts   InMcastPkts   InBcastPkts
--------------------------------------------------------------------------------
mgmt0                42754            --             0            --
Eth2/2            41423421        112708        125997        180167
Eth5/2            39686276        119152         93284        180100
Eth5/6             4216279          9530         31268            40
Veth1                    0             0             0             0
Veth2                    0             0             0             0
Veth3                    0             0             0             0
Veth4                    0             0             0             0
Veth5                    0             0             0             0
Veth6                    0             0             0             0
Veth7                    0             0             0             0
Veth100                  0             0             0             0

--------------------------------------------------------------------------------
Port             OutOctets  OutUcastPkts  OutMcastPkts  OutBcastPkts
--------------------------------------------------------------------------------
mgmt0                 3358            --            --            --
Eth2/2            23964739        116150           516         52768
Eth5/2            26419473        111598           571         52420
Eth5/6             1042930          9548           536            14
Veth1               393589             0          6150             0
Veth2               393600             0          6150             0
Veth3               393600             0          6150             0
Veth4                    0             0             0             0
Veth5                    0             0             0             0
Veth6                    0             0             0             0
Veth7                    0             0             0             0
Veth100                  0             0             0             0

switchyup#

          Configuration Examples for vEthernet Interfaces

          This example shows how to configure a vEthernet access interface and assign the access VLAN for that interface:

          switch# configure terminal
switch(config)# interface vethernet 100
switch(config-if)# switchport
switch(config-if)# switchport mode access
switch(config-if)# switchport access vlan 5
switch(config-if)#

          This example shows how to configure a Layer 2 trunk interface, assign the native VLAN and the allowed VLANs, and configure the device to tag the native VLAN traffic on the trunk interface:

          switch# configure terminal
switch(config)# interface vethernet 1
switch(config-if)# switchport
switch(config-if)# switchport mode trunk
switch(config-if)# switchport trunk native vlan 10
switch(config-if)# switchport trunk allowed vlan 5, 10
switch(config-if)#

          Feature History for vEthernet Interfaces

          Feature Name

          Releases

          Feature Information

          Global vEthernet interface controls

          4.2(1)SV1(4)

          You can enable or disable the following automatic vEthernet interface controls:

          • Deleting unused vEthernet interfaces
          • Purging of manual vEthernet configurations
          • Creating vEthernet interfaces

          vEthernet interface parameters

          4.0(4)SV1(1)

          This feature was introduced