Strict active/standby interface backup configuration example

As shown in Figure 3:

• Specify GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3 on Router A to back up GigabitEthernet 1/0/1.

• Assign GigabitEthernet 1/0/2 a higher priority than GigabitEthernet 1/0/3.

• Set the up and down delay timers to 10 seconds for the backup interfaces.

1. Assign IP addresses to interfaces, as shown in Figure 3. (Details not shown.)

2. Configure routes:

   # On Router A, configure static routes to 192.168.2.0/24 through the primary and backup interfaces.

   <RouterA> system-view
   [RouterA] ip route-static 192.168.2.0 24 gigabitethernet 1/0/1 1.1.1.2
   [RouterA] ip route-static 192.168.2.0 24 gigabitethernet 1/0/2 2.2.2.2
   [RouterA] ip route-static 192.168.2.0 24 gigabitethernet 1/0/3 3.3.3.2
   

   # On Router B, configure static routes to 192.168.1.0/24.

   <RouterB> system-view
   [RouterB] ip route-static 192.168.1.0 24 gigabitethernet 1/0/1 1.1.1.1
   [RouterB] ip route-static 192.168.1.0 24 gigabitethernet 1/0/2 2.2.2.1
   [RouterB] ip route-static 192.168.1.0 24 gigabitethernet 1/0/3 3.3.3.1
   

3. On Router A, configure backup interfaces and switchover delays:

   # Specify GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3 to back up GigabitEthernet 1/0/1, and assign them a priority of 30 and 20, respectively.

   [RouterA] interface gigabitethernet 1/0/1
   [RouterA-GigabitEthernet1/0/1] backup interface gigabitethernet 1/0/2 30
   [RouterA-GigabitEthernet1/0/1] backup interface gigabitethernet 1/0/3 20
   

   # Set both up and down delay timers to 10 seconds.

   [RouterA-GigabitEthernet1/0/1] backup timer delay 10 10
   

# Display states of the primary and backup interfaces.

[RouterA-GigabitEthernet1/0/1] display interface-backup state

Interface: GE1/0/1

  UpDelay: 10 s
  DownDelay: 10 s

State: UP

  Backup interfaces:

GE1/0/2 Priority: 30 State: STANDBY

GE1/0/3 Priority: 20 State: STANDBY

The output shows that GigabitEthernet 1/0/1 is in UP state and the two backup interfaces are in STANDBY state.

# Shut down the primary interface GigabitEthernet 1/0/1.

[RouterA-GigabitEthernet1/0/1] shutdown

# Verify that the backup interface GigabitEthernet 1/0/2 comes up 10 seconds after the primary interface goes down.

[RouterA-GigabitEthernet1/0/1] display interface-backup state

Interface: GE1/0/1

  UpDelay: 10 s
  DownDelay: 10 s

State: DOWN

  Backup interfaces:

GE1/0/2 Priority: 30 State: UP

GE1/0/3 Priority: 20 State: STANDBY