Example for Configuring Static BFD for IPv4 Static Routes

Procedure

1. Create VLANs, add interfaces to the VLANs, and assign IP addresses to the VLANIF interfaces. (Details are not provided here.)
2. Configure device names. (Details are not provided here.)
3. Configure a BFD session between SwitchA and SwitchB.

   # Create a BFD session on SwitchA.

   <SwitchA> system-view

   [~SwitchA] bfd

   [*SwitchA-bfd] quit

   [*SwitchA] bfd aa bind peer-ip 10.1.1.2

   [*SwitchA-bfd-session-aa] discriminator local 10

   [*SwitchA-bfd-session-aa] discriminator remote 20

   [*SwitchA-bfd-session-aa] commit

   [~SwitchA-bfd-session-aa] quit

   # Create a BFD session on SwitchB.

   <SwitchB> system-view

   [~SwitchB] bfd

   [*SwitchB-bfd] quit

   [*SwitchB] bfd bb bind peer-ip 10.1.1.1

   [*SwitchB-bfd-session-bb] discriminator local 20

   [*SwitchB-bfd-session-bb] discriminator remote 10

   [*SwitchB-bfd-session-bb] commit

   [~SwitchB-bfd-session-bb] quit

4. Configure a default static route and bind a BFD session to the default static route.

   # Configure a default static route to the external network on SwitchA and bind the default static route to the BFD session named aa.

   [~SwitchA] ip route-static 0.0.0.0 0 10.1.1.2 track bfd-session aa

   [*SwitchA] commit

5. Verify the configuration.

   # After the configuration is complete, run the display bfd session all command on SwitchA and SwitchB. The command output shows that the BFD session has been established and its status is Up. Run the display current-configuration | include bfd command. The command output shows that the BFD session has been bound to the static route.

   Take the display information on SwitchA as an example.

   [~SwitchA] display bfd session all

   S: Static session
   D: Dynamic session
   IP: IP session
   IF: Single-hop session
   PEER: Multi-hop session
   AUTO: Automatically negotiated session
   --------------------------------------------------------------------------------
   Local  Remote PeerIpAddr      State     Type        InterfaceName
   --------------------------------------------------------------------------------
   10     20     10.1.1.2         Up       S/IP-PEER   -
   --------------------------------------------------------------------------------
   

   [~SwitchA] display current-configuration | include bfd

   bfd

   bfd aa bind peer-ip 10.1.1.2

   ip route-static 0.0.0.0 0.0.0.0 10.1.1.2 track bfd-session aa 

   # Check the IP routing table on SwitchA, and you can find that the static route exists in the routing table.

   [~SwitchA] display ip routing-table

   Proto: Protocol        Pre: Preference
   Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route

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

   Routing Table: _Public_

            Destinations : 3        Routes : 3

   Destination/Mask    Proto  Pre  Cost     Flags NextHop         Interface

           0.0.0.0/0   Static 60   0           RD  10.1.1.2         Vlanif10

           10.1.1.0/24  Direct 0    0           D  10.1.1.1         Vlanif10

           10.1.1.1/32  Direct 0    0           D  127.0.0.1       Vlanif10

   Run the shutdown command on 10GE1/0/1 of SwitchB to simulate a link fault.

   [~SwitchB] interface 10GE 1/0/1

   [~SwitchB-10GE1/0/1] shutdown

   [*SwitchB-10GE1/0/1] commit

   # Check the routing table on SwitchA, and you can find that the default static route 0.0.0.0/0 does not exist. This is because when the default static route is bound to a BFD session, BFD rapidly notifies that the bound static route is unavailable after BFD detects a link fault.

   [~SwitchA] display ip routing-table

   Proto: Protocol        Pre: Preference
   Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route

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

   Routing Table: _Public_

            Destinations : 2        Routes : 2

   Destination/Mask    Proto  Pre  Cost     Flags NextHop         Interface

           10.1.1.0/24  Direct 0    0           D  10.1.1.1         Vlanif10

           10.1.1.1/32  Direct 0    0           D  127.0.0.1       Vlanif10