Changing the LAG membership for an interface

Prerequisites

You must be in the global configuration context: switch(config)#

Procedure
  1. Remove an interface from the LAG. Enter:
    switch(config)# interface <PORT-NUM>
    switch(config-if)# no lag <ID>

    For example:

    switch(config)# interface 1/1/1
    switch(config-if)# no lag 100
    switch(config-if)# show running-config
    Current configuration:
    !
    ...
    !
    vlan 1
    interface lag 100
        no shutdown
        no routing
        vlan trunk native 1
        vlan trunk allowed all
    interface 1/1/1
    interface 1/1/2
        no shutdown
        lag 100
    switch(config-if)#

    After removing a physical interface from a LAG, the interface associated with the LAG becomes L3 ports with default L3 configurations and administrative down. For example, suppose interface 1/1/1 was part of LAG 3 and you had administratively enabled the interface. If you later remove interface 1/1/1 from LAG 3, the administrative status automatically changes to down. If you want to use the interface again, you must administratively enable it again.

  2. Create the LAG to which you want to add the interface:
    switch(config-if)# interface lag 10
    For example:
    switch(config-if)# interface lag 10
    switch(config-lag-if)# no shutdown
    switch(config-lag-if)# no routing
    switch(config-lag-if)# vlan trunk native 1
  3. Add the interface from Step 1 to the newly created LAG:
    switch(config)# interface 1/1/1
    switch(config-if)# lag 10
    For example:
    switch(config)# interface 1/1/1
    switch(config-if)# lag 10
    switch(config-if)# show running-config
    Current configuration:
    !
    ...
    !
    vlan 1
    interface lag 10
        no shutdown
        no routing
        vlan trunk native 1
        vlan trunk allowed all
    interface lag 100
        no shutdown
        no routing
        vlan trunk native 1
        vlan trunk allowed all
    interface 1/1/1
        lag 10
    interface 1/1/2
        no shutdown
        lag 100
    Notice that interface 1/1/1 in the previous example is still not active, even though it has been added to LAG 10. To change the administrative state of the member interface, enter the no shutdown command at the interface level. For example:
    switch(config-if)# interface 1/1/1
    switch(config-if)# no shutdown
    switch(config-if)# show running-config
    Current configuration:
    !
    ...
    !
    vlan 1
    interface lag 10
        no shutdown
        no routing
        vlan trunk native 1
        vlan trunk allowed all
    interface lag 100
        no shutdown
        no routing
        vlan trunk native 1
        vlan trunk allowed all
    interface 1/1/1
        no shutdown
        lag 10
    interface 1/1/2
        no shutdown
        lag 100