Example for Configuring Static BFD for IPv4 Static Routes
To improve network reliability, you can configure static BFD for IPv4 static routes to fast detect link failures and speed up route convergence.
Networking Requirements
On the network shown in Figure 1, DeviceA is connected to DeviceB through Switch C. It is required that DeviceA communicate with other devices through static default routes and that a BFD session be set up between DeviceA and DeviceB to detect link faults.
Configuration Roadmap
The configuration roadmap is as follows:
Configure a BFD session between DeviceA and DeviceB to detect the link between the two devices.
Configure a default static route from DeviceA to the external network and bind the default static route to the BFD session.
Data Preparation
To complete the configuration, you need the following data:
Peer IP address to be detected by BFD
Local discriminator and remote discriminator of a BFD session
Default values of the local detection multiplier and of the minimum intervals at which BFD Control packets are sent and received
Procedure
- Configure an IP address for each interface.
For configuration details, see "Configuration Files" in this section.
- Configure a BFD session between DeviceA and DeviceB.
# On DeviceA, configure a BFD session between DeviceA and DeviceB.
<DeviceA> system-view [~DeviceA] bfd [*DeviceA-bfd] quit [*DeviceA] bfd aa bind peer-ip 1.1.1.2 [*DeviceA-bfd-session-aa] discriminator local 10 [*DeviceA-bfd-session-aa] discriminator remote 20 [*DeviceA-bfd-session-aa] commit [~DeviceA-bfd-session-aa] quit
# On DeviceB, configure a BFD session between DeviceA and DeviceB.
<DeviceB> system-view [~DeviceB] bfd [*DeviceB-bfd] quit [*DeviceB] bfd bb bind peer-ip 1.1.1.1 [*DeviceB-bfd-session-bb] discriminator local 20 [*DeviceB-bfd-session-bb] discriminator remote 10 [*DeviceB-bfd-session-bb] commit [~DeviceB-bfd-session-bb] quit
- Configure a default static route and bind it to a BFD session.
# On DeviceA, configure a default static route to the external network and bind it to BFD session named aa.
[~DeviceA] ip route-static 0.0.0.0 0 1.1.1.2 track bfd-session aa
- Verify the configuration.
# Run the display bfd session all command on DeviceA and DeviceB. The command output shows that a BFD session has been established and is Up. Then, run the display current-configuration | include bfd command in the system view. The command output shows that the default static route has been bound to the BFD session.
Use the command output on DeviceA as an example.
[~DeviceA] display bfd session all -------------------------------------------------------------------------------- Local Remote PeerIpAddr State Type InterfaceName -------------------------------------------------------------------------------- 10 20 1.1.1.2 Up S_IP_PEER - -------------------------------------------------------------------------------- Total UP/DOWN Session Number : 1/0 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 1.1.1.2 Up S_IP_PEER - -------------------------------------------------------------------------------- Total UP/DOWN Session Number : 1/0 [~DeviceA] display current-configuration | include bfd bfd bfd aa bind peer-ip 1.1.1.2 ip route-static 0.0.0.0 0.0.0.0 1.1.1.2 track bfd-session aa
# Check the IP routing table of DeviceA. The command output shows that the static route exists in the routing table.
[~DeviceA] display ip routing-table Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route ------------------------------------------------------------------------------ Routing Table: Public Destinations : 5 Routes : 5 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 Static 60 0 RD 1.1.1.2 GigabitEthernet0/1/0 1.1.1.0/24 Direct 0 0 D 1.1.1.1 GigabitEthernet0/1/0 1.1.1.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/1/0 1.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/1/0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
# Run the shutdown command on GE 0/1/0 of DeviceB to simulate a link fault.
[~DeviceB] interface GigabitEthernet 0/1/0 [~DeviceB-GigabitEthernet0/1/0] shutdown
# Check the IP routing table of DeviceA. The command output shows that default route 0.0.0.0/0 does not exist. This is because the default static route has been bound to a BFD session. When BFD detects the link fault, BFD rapidly notifies that the bound static route becomes unavailable.
[*DeviceA] display ip routing-table Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route ------------------------------------------------------------------------------ Routing Table: Public Destinations : 4 Routes : 4 Destination/Mask Proto Pre Cost Flags NextHop Interface 1.1.1.0/24 Direct 0 0 D 1.1.1.1 GigabitEthernet0/1/0 1.1.1.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/1/0 1.1.1.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/1/0 255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
Configuration Files
DeviceA configuration file
# sysname DeviceA # bfd # interface GigabitEthernet0/1/0 undo shutdown ip address 1.1.1.1 255.255.255.0 # ip route-static 0.0.0.0 0.0.0.0 1.1.1.2 track bfd-session aa # bfd aa bind peer-ip 1.1.1.2 discriminator local 10 discriminator remote 20 # return
DeviceB configuration file
# sysname DeviceB # bfd # interface GigabitEthernet0/1/0 undo shutdown ip address 1.1.1.2 255.255.255.0 # interface GigabitEthernet0/1/8 undo shutdown ip address 2.2.2.2 255.255.255.0 # bfd bb bind peer-ip 1.1.1.1 discriminator local 20 discriminator remote 10 # return