拓朴如下：

主要配置如下：

[R1]
interface GigabitEthernet0/0/0
 ip address 10.1.1.1 255.255.255.0 
 vrrp vrid 1 virtual-ip 10.1.1.254
 vrrp vrid 1 priority 200
 vrrp vrid 1 preempt-mode timer delay 20
#
interface GigabitEthernet0/0/1
 ip address 13.1.1.1 255.255.255.0 
#
ospf 1 router-id 1.1.1.1 
 area 0.0.0.0 
  network 0.0.0.0 255.255.255.255 
#

[R2]
interface GigabitEthernet0/0/0
 ip address 10.1.1.2 255.255.255.0 
 vrrp vrid 1 virtual-ip 10.1.1.111
#
interface GigabitEthernet0/0/1
 ip address 23.1.1.2 255.255.255.0 
#
interface GigabitEthernet0/0/2
#
ospf 1 router-id 2.2.2.2 
 area 0.0.0.0 
  network 0.0.0.0 255.255.255.255 
#

[R3]
interface GigabitEthernet0/0/1
 ip address 13.1.1.3 255.255.255.0 
#
interface GigabitEthernet0/0/2
 ip address 23.1.1.3 255.255.255.0 
#
interface LoopBack0
 ip address 3.3.3.3 255.255.255.255 
#
ospf 1 router-id 3.3.3.3 
 area 0.0.0.0 
  network 0.0.0.0 255.255.255.255 
#

检测：

断开R1的G0/0/0口，发现丢了一个包后，仍能ping通R3的环回口3.3.3.3