As shown in Figure 1, Host A accesses Host B through the default gateway.

The requirements are as follows:

• CX-A and CX-B form a VRRP backup group that serves as the default gateway for Host A.
• Normally, CX-A serves as the gateway. When CX-A fails, CX-B serves as the gateway.
• CX-A continues to function as the master CX device within 20 seconds after it recovers.

Figure 1 Networking diagram of configuring VRRP in the master/backup mode

Procedure

1. Configure network interconnection between devices.
   # Configure the default gateway of Host A with 10.1.1.111 and the default gateway of Host B with 20.1.1.1.
   # Configure CX-A, CX-B and CX-C to use OSPF for interconnection.
2. Configure VRRP.
   # On CX-A, configure the IP address of the interface, create backup group 1 and configure the priority of CX-A in this group with 120 (as the master CX device).

   <CX-A> system-view

   [CX-A] interface gigabitethernet 2/0/0

   [CX-A-GigabitEthernet2/0/0] undo shutdown

   [CX-A-GigabitEthernet2/0/0] ip address 10.1.1.1 24

   [CX-A-GigabitEthernet2/0/0] vrrp vrid 1 virtual-ip 10.1.1.111

   [CX-A-GigabitEthernet2/0/0] vrrp vrid 1 priority 120

   [CX-A-GigabitEthernet2/0/0] vrrp vrid 1 preempt-mode timer delay 20

   [CX-A-GigabitEthernet2/0/0] quit

   [CX-A] quit

   # On CX-B, configure the IP address of the interface, create backup group 1 and configure the priority of CX-B in this group with the default value 100 (as the backup CX device).

   <CX-B> system-view

   [CX-B] interface gigabitethernet 2/0/0

   [CX-B-GigabitEthernet2/0/0] undo shutdown

   [CX-B-GigabitEthernet2/0/0] ip address 10.1.1.2 24

   [CX-B-GigabitEthernet2/0/0] vrrp vrid 1 virtual-ip 10.1.1.111

   [CX-B] quit
3. Verify the configuration.
   • Check that the VRRP backup group can serve as a gateway.
     After the previous configuration, Host A can ping through Host B.
     Running the display vrrp command on CX-A, you can view that the status of CX-A is Master. Running thedisplay vrrp command on CX-B, you can view that the CX-B is Backup.

     <CX-A> display vrrp

       GigabitEthernet2/0/0 | Virtual CX-1

         state          : Master

         Virtual IP     : 10.1.1.111

         Master IP       : 10.1.1.1

         PriorityRun    : 120

         PriorityConfig : 120

         MasterPriority : 120

         Preempt        : YES        Delay Time : 20

         TimerRun       : 1

         TimerConfig    : 1

         Auth Type      : NONE

         Virtual Mac    :  0000-5e00-0101

         Check TTL      : YES

         Config type    : normal-vrrp

     <CX-B> display vrrp

       GigabitEthernet2/0/0 | Virtual CX-1

         state          : Backup

         Virtual IP     : 10.1.1.111

         Master IP      : 10.1.1.1

         PriorityRun    : 100

         PriorityConfig : 100

         MasterPriority : 120

         Preempt        : YES      Delay Time : 0

         TimerRun       : 1

         TimerConfig    : 1

         Auth Type      : NONE

         Virtual Mac    :  0000-5e00-0101

         Check TTL      : YES

         Config type    : normal-vrrp

     Running the display ip routing-table command on CX-A and CX-B, you can view a direct route with the destination address being the virtual IP address on CX-A, and an OSPF route to the same destination on CX-B.
     The displays on CX-A and CX-B are as follows.

     <CX-A> display ip routing-table

     Route Flags: R - relied, D - download to fib

     ------------------------------------------------------------------------------

     Routing Tables: Public

              Destinations : 10       Routes : 10

     Destination/Mask    Proto    Pre  Cost     Flags    NextHop         Interface

          10.1.1.0/24    Direct   0     0         D      10.1.1.1        GigabitEthernet2/0/0

          10.1.1.1/32    Direct   0     0         D      127.0.0.1       InLoopBack0

          10.1.1.111/32    Direct  0     0         D      127.0.0.1      InLoopBack0

          20.1.1.0/24    OSPF     10    2         D      192.168.1.2     Pos1/0/0

          127.0.0.0/8    Direct   0     0         D      127.0.0.1       InLoopBack0

         127.0.0.1/32    Direct   0     0         D      127.0.0.1       InLoopBack0

       192.168.1.0/24    Direct   0     0         D      192.168.1.1     Pos1/0/0

       192.168.1.1/32    Direct   0     0         D      127.0.0.1       InLoopBack0

       192.168.1.2/32    Direct   0     0         D      192.168.1.2     Pos1/0/0

       192.168.2.0/24    OSPF     10    2         D      10.1.1.2        GigabitEthernet2/0/0

     <CX-B> display ip routing-table

     Route Flags: R - relied, D - download to fib

     ------------------------------------------------------------------------------

     Routing Tables: Public

              Destinations : 10       Routes : 10

     Destination/Mask    Proto    Pre  Cost     Flags   NextHop         Interface

          10.1.1.0/24    Direct   0     0         D     10.1.1.2        InLoopBack0

          10.1.1.2/32    Direct   0     0         D     127.0.0.1       InLoopBack0

          10.1.1.111/32    OSPF    10    2         D     10.1.1.1       InLoopBack0

          20.1.1.0/24    OSPF     10    2         D     192.168.2.2     Pos1/0/0

          127.0.0.0/8    Direct   0     0         D     127.0.0.1       InLoopBack0

         127.0.0.1/32    Direct   0     0         D     127.0.0.1       InLoopBack0

       192.168.1.0/24    OSPF     10    2         D     10.1.1.1        GigabitEthernet2/0/0

       192.168.2.0/24    Direct   0     0         D     192.168.2.1     Pos1/0/0

       192.168.2.1/32    Direct   0     0         D     127.0.0.1       InLoopBack0

       192.168.2.2/32    Direct   0     0         D     192.168.2.2     Pos1/0/0

   • Check whether CX- B can become the master when CX-A fails.
     To simulate the election of the master CX device when CX-A fails, run the shutdown command on the GE 2/0/0 on CX-A.
     Running the display vrrp command on CX-B to view the VRRP status, you can view that CX-B is in the Master state. The command output is as follows:

     <CX-B> display vrrp

     GigabitEthernet2/0/0 | Virtual CX-1

         state          : Master

         Virtual IP     : 10.1.1.111

         Master IP       : 10.1.1.2

         PriorityRun    : 100

         PriorityConfig : 100

         MasterPriority : 100

         Preempt        : YES      Delay Time : 0

         TimerRun       : 1

         TimerConfig    : 1

         Auth Type      : NONE

         Virtual Mac    :  0000-5e00-0101

         Check TTL      : YES

         Config type    : normal-vrrp

   • Check that CX-A can perform preemption after recovering.
     Run the undo shutdown command on GE 2/0/0. On CX-A, run the display vrrp command to view VRRP status 20 seconds after GE 2/0/0 being Up. You can view that CX-A restores to be the master CX device.