Configuring a logical interface on a physical port or port-channel (LAG)

This task configures a logical interface on a physical (Ethernet) port and a port-channel (Link Aggregation Group, or LAG) interface.

About this task

Refer to the Usage Guidelines for the logical-interface command for complete details.

Procedure

Do the following to configure a logical interface on an Ethernet port.
1. Enter global configuration mode.
```
device# configure terminal
```
2. Specify an Ethernet interface.
```
device(config)# interface ethernet 0/6
```
3. Enter the switchport command to configure the parent interface as switchport.
```
device(conf-if-eth-0/6)# switchport
```
4. Enter the switchport mode trunk-no-default-native command to enable an explicit untagged LIF to be configured.
```
device(conf-if-eth-0/6)# switchport mode trunk-no-default-native
```
5. Enable the interface.
```
device(conf-if-eth-0/6)# no shutdown
```
6. Enter the logical-interface command, specify a service instance, and enter LIF configuration mode.
```
device(conf-if-eth-0/6)# logical-interface ethernet 0/6.120
```
7. (Optional) Enter the name command to facilitate the management of the LIF.
```
device(conf-if-eth-lif-0/6.120)# name myLIF120
```
8. Enter the vlan command with the inner-vlan option to specify an interface and create dual-tag VLANs.
```
device(conf-if-eth-lif-0/6.120)# vlan 120 inner-vlan 200
```
9. Alternatively, enter the untagged vlan command to specify that the LIF is to receive untagged packets.
```
device(conf-if-eth-lif-0/6.120)# untagged vlan 120
```
  See the Usage Guidelines for the vlan (LIF) command.
10. (Optional) By default, the administrative state of the LIF is "no shutdown." To remove the port from participating in any data traffic without having to shut down the physical interface, enter the no form of the shutdown (LIF) command.
```
device(conf-if-eth-lif-0/6.120)# no shutdown
```
11. (Optional) For convenience, you can also enter up to two options in a single command line, as in the following examples.
```
device(conf-if-eth-0/6)# logical-interface ethernet 0/6.120 name myLIF120

device(conf-if-eth-0/6)# logical-interface ethernet 0/6.120 vlan 120
```
To configure a port-channel, configure the basic LIF parameters and options as in Step 1.
1. Specify a port-channel, set its mode to "trunk-no-default-native," and specify a logical interface service instance.
```
device(config)# interface port-channel 10
device(config-port-channel-10)# switchport mode trunk-no-default-native 
device(config-port-channel-10)# logical-interface port-channel 10.3
device(config-if-po-lif-10.3)# 
```
2. Repeat additional substeps in Step 1 as appropriate.