BFD for static routes configuration example (indirect next hop)

InFigure 4, Switch A has a route to interface Loopback 1 (2.2.2.9/32) on Switch B, with the output interface VLAN-interface 10. Switch B has a route to interface Loopback 1 (1.1.1.9/32) on Switch A, with the output interface VLAN-interface 12. Switch D has a route to 1.1.1.9/32, with the output interface VLAN-interface 10, and a route to 2.2.2.9/32, with the output interface VLAN-interface 12.

Configure a static route to subnet 120.1.1.0/24 on Switch A, and configure a static route to subnet 121.1.1.0/24 on Switch B. Enable BFD for both routes. Configure a static route to subnet 120.1.1.0/24 and a static route to subnet 121.1.1.0/24 on both Switch C and Switch D. When the link between Switch A and Switch B through Switch D fails, BFD can detect the failure immediately and inform Switch A and Switch B to communicate through Switch C.

1. Configure IP addresses for 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 Switch D.

   <SwitchA> system-view
   [SwitchA] bfd multi-hop min-transmit-interval 500
   [SwitchA] bfd multi-hop min-receive-interval 500
   [SwitchA] bfd multi-hop detect-multiplier 9
   [SwitchA] ip route-static 120.1.1.0 24 2.2.2.9 bfd control-packet bfd-source 1.1.1.9
   [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 Switch D.

   <SwitchB> system-view
   [SwitchB] bfd multi-hop min-transmit-interval 500
   [SwitchB] bfd multi-hop min-receive-interval 500
   [SwitchB] bfd multi-hop detect-multiplier 9
   [SwitchB] ip route-static 121.1.1.0 24 1.1.1.9 bfd control-packet bfd-source 2.2.2.9
   [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
   

   # Configure static routes on Switch D.

   <SwitchD> system-view
   [SwitchD] ip route-static 120.1.1.0 24 11.1.1.1
   [SwitchD] ip route-static 121.1.1.0 24 12.1.1.1
   

# 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            1.1.1.9         2.2.2.9         Up       2000ms      N/A

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.