Strict active/standby interface backup configuration example
Network requirements
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.
Figure 3: Network diagram
Configuration procedure
Assign IP addresses to interfaces, as shown in Figure 3. (Details not shown.)
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
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
Verifying the configuration
# 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