BFD for static routes configuration example (direct next hop)

Network requirements

Configure the following, as shown in Figure 3:

When the link between Switch A and Switch B through the Layer 2 switch fails, BFD can detect the failure immediately. Switch A then communicates with Switch B through Switch C.

Figure 3: Network diagram

Table 4: Interface and IP address assignment

Device

Interface

IP address

Switch A

VLAN-interface 10

12.1.1.1/24

Switch A

VLAN-interface 11

10.1.1.102/24

Switch B

VLAN-interface 10

12.1.1.2/24

Switch B

VLAN-interface 13

13.1.1.1/24

Switch C

VLAN-interface 11

10.1.1.100/24

Switch C

VLAN-interface 13

13.1.1.2/24

Configuration procedure

  1. Configure IP addresses for the interfaces. (Details not shown.)

  2. Configure static routes and BFD:

    # Configure static routes on Switch A and enable BFD control mode for the static route that traverses the Layer 2 switch.

    <SwitchA> system-view
    [SwitchA] interface vlan-interface 10
    [SwitchA-vlan-interface10] bfd min-transmit-interval 500
    [SwitchA-vlan-interface10] bfd min-receive-interval 500
    [SwitchA-vlan-interface10] bfd detect-multiplier 9
    [SwitchA-vlan-interface10] quit
    [SwitchA] ip route-static 120.1.1.0 24 vlan-interface 10 12.1.1.2 bfd control-packet
    [SwitchA] ip route-static 120.1.1.0 24 vlan-interface 11 10.1.1.100 preference 65
    [SwitchA] quit
    

    # Configure static routes on Switch B and enable BFD control mode for the static route that traverses the Layer 2 switch.

    <SwitchB> system-view
    [SwitchB] interface vlan-interface 10
    [SwitchB-vlan-interface10] bfd min-transmit-interval 500
    [SwitchB-vlan-interface10] bfd min-receive-interval 500
    [SwitchB-vlan-interface10] bfd detect-multiplier 9
    [SwitchB-vlan-interface10] quit
    [SwitchB] ip route-static 121.1.1.0 24 vlan-interface 10 12.1.1.1 bfd control-packet
    [SwitchB] ip route-static 121.1.1.0 24 vlan-interface 13 13.1.1.2 preference 65
    [SwitchB] quit
    

    # Configure static routes on Switch C.

    <SwitchC> system-view
    [SwitchC] ip route-static 120.1.1.0 24 13.1.1.1
    [SwitchC] ip route-static 121.1.1.0 24 10.1.1.102
    

Verifying the configuration

# Display BFD sessions on Switch A.

<SwitchA> display bfd session

 Total Session Num: 1     Up Session Num: 1     Init Mode: Active

 IPv4 Session Working Under Ctrl Mode:

 LD/RD          SourceAddr      DestAddr        State    Holdtime    Interface
 4/7            12.1.1.1        12.1.1.2        Up       2000ms      Vlan10

The output shows that the BFD session has been created.

# Display the static routes on Switch A.

<SwitchA> display ip routing-table protocol static

Summary Count : 1

Static Routing table Status : <Active>
Summary Count : 1

Destination/Mask    Proto  Pre  Cost         NextHop         Interface
120.1.1.0/24        Static 60   0            12.1.1.2        Vlan10

Static Routing table Status : <Inactive>
Summary Count : 0

The output shows that Switch A communicates with Switch B through VLAN-interface 10. Then the link over VLAN-interface 10 fails.

# Display static routes on Switch A.

<SwitchA> display ip routing-table protocol static

Summary Count : 1

Static Routing table Status : <Active>
Summary Count : 1

Destination/Mask    Proto  Pre  Cost         NextHop         Interface
120.1.1.0/24        Static 65   0            10.1.1.100      Vlan11

Static Routing table Status : <Inactive>
Summary Count : 0

The output shows that Switch A communicates with Switch B through VLAN-interface 11.