Configuration examples for subinterfaces

Updated: April 24, 2026

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Details practical configuration examples for subinterfaces, illustrating common deployment scenarios and best practices for effective network segmentation and traffic handling.

This section provides configuration examples for subinterfaces.

When you create a subinterface that does not specify an IP MTU value, the subinterface inherits the IP MTU value from the parent interface. If you want the subinterface to have a different IP MTU value, use the ip mtu command in the subinterface configuration to set the IP MTU for the sub interface.

The following is a configuration example for subinterfaces:


interface GigabitEthernet0/0/0
 mtu 1504
 no ip address
!
interface GigabitEthernet0/0/0.9
 encapsulation dot1Q 9
 no shutdown
 ip address 192.168.9.32 255.255.255.0
!
interface Tunnel9
 no shutdown
 ip unnumbered GigabitEthernet0/0/0.9
 no ip redirects
 ipv6 unnumbered GigabitEthernet0/0/0.9
 no ipv6 redirects
 tunnel source GigabitEthernet0/0/0.9
 tunnel mode sdwan
!
sdwan
 interface GigabitEthernet0/0/0.9
  tunnel-interface
   encapsulation ipsec
   color private1
  !
 !

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