VRRP on sub-interfaces

It is no problem to run Virtual Router Redundancy Protocol (VRRP) on sub-interfaces. There will be no conflict between the VRRP instances.

Configuration

Here is a sample configuration of two routers with two sub-interfaces:

R1#

interface GigabitEthernet0/0
 no ip address
 duplex auto
 speed auto
 media-type rj45
!
interface GigabitEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.1 255.255.255.0
 vrrp 10 ip 192.168.10.254
!
interface GigabitEthernet0/0.20
 encapsulation dot1Q 20
 ip address 192.168.20.1 255.255.255.0
 vrrp 20 ip 192.168.20.254

R2#


interface GigabitEthernet0/0
 no ip address
 duplex auto
 speed auto
 media-type rj45
!
interface GigabitEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.2 255.255.255.0
 vrrp 10 ip 192.168.10.254
!
interface GigabitEthernet0/0.20
 encapsulation dot1Q 20
 ip address 192.168.20.2 255.255.255.0
 vrrp 20 ip 192.168.20.254

Verification

Here is R1:

R1#show vrrp 
GigabitEthernet0/0.10 - Group 10 
  State is Backup  
  Virtual IP address is 192.168.10.254
  Virtual MAC address is 0000.5e00.010a
  Advertisement interval is 1.000 sec
  Preemption enabled
  Priority is 100 
  Master Router is 192.168.10.2, priority is 100 
  Master Advertisement interval is 1.000 sec
  Master Down interval is 3.609 sec (expires in 3.060 sec)

GigabitEthernet0/0.20 - Group 20 
  State is Backup  
  Virtual IP address is 192.168.20.254
  Virtual MAC address is 0000.5e00.0114
  Advertisement interval is 1.000 sec
  Preemption enabled
  Priority is 100 
  Master Router is 192.168.20.2, priority is 100 
  Master Advertisement interval is 1.000 sec
  Master Down interval is 3.609 sec (expires in 3.145 sec)

And R2:

R2#show vrrp 
GigabitEthernet0/0.20 - Group 20 
  State is Master  
  Virtual IP address is 192.168.20.254
  Virtual MAC address is 0000.5e00.0114
  Advertisement interval is 1.000 sec
  Preemption enabled
  Priority is 100 
  Master Router is 192.168.20.2 (local), priority is 100 
  Master Advertisement interval is 1.000 sec
  Master Down interval is 3.609 sec

GigabitEthernet0/0.10 - Group 10 
  State is Master  
  Virtual IP address is 192.168.10.254
  Virtual MAC address is 0000.5e00.010a
  Advertisement interval is 1.000 sec
  Preemption enabled
  Priority is 100 
  Master Router is 192.168.10.2 (local), priority is 100 
  Master Advertisement interval is 1.000 sec
  Master Down interval is 3.609 sec