Example for Configuring Dynamic BFD for IPv4 Static Routes

Dynamic BFD for IPv4 static routes can fast detect link failures.

Networking Requirements

On the network shown in Figure 1, DeviceA is connected to DeviceB through SwitchC. It is required that DeviceA communicate with other Devices through static default routes and that a BFD session be established between DeviceA and DeviceB to detect link failures.

Figure 1 Networking for configuring dynamic BFD for static routes

Interfaces 1 and 2 in this example represent GE 0/1/0 and GE 0/1/8, respectively.

Precautions

When configuring dynamic BFD for static routes, note the following:

BFD has been enabled globally.
The parameters configured on the two ends of a BFD session must be consistent.

Configuration Roadmap

The configuration roadmap is as follows:

On DeviceA, configure an IPv4 static route to DeviceB.
Configure dynamic BFD for static routes.

Data Preparation

To complete the configuration, you need the following data:

Peer IP address to be detected by BFD
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 static routes.

# On DeviceA, configure a static route to 2.2.2.2/32.

[~DeviceA] ip route-static 2.2.2.2 32 10.10.1.2
[*DeviceA] commit

# Check the IP routing table of DeviceA. The following 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 : 10        Routes : 10

Destination/Mask    Proto  Pre  Cost        Flags NextHop         Interface

        1.1.1.1/32  Direct 0    0             D  127.0.0.1       LoopBack0
        2.2.2.2/32  Static 60   0             RD 10.10.1.2       GigabitEthernet0/1/0
      127.0.0.0/8   Direct 0    0             D  127.0.0.1       InLoopBack0
      127.0.0.1/32  Direct 0    0             D  127.0.0.1       InLoopBack0
127.255.255.255/32  Direct 0    0             D  127.0.0.1       InLoopBack0
255.255.255.255/32  Direct 0    0             D  127.0.0.1       InLoopBack0
      10.10.1.0/24  Direct 0    0             D  10.10.1.1       GigabitEthernet0/1/0
      10.10.1.1/32  Direct 0    0             D  127.0.0.1       GigabitEthernet0/1/0
      10.10.1.2/32  Direct 0    0             D  10.10.1.2       GigabitEthernet0/1/0
    10.10.1.255/32  Direct 0    0             D  127.0.0.1       GigabitEthernet0/1/0

# On DeviceB, configure a static route to 1.1.1.1/32.

[~DeviceB] ip route-static 1.1.1.1 32 10.10.1.1
[*DeviceB] commit

Configure dynamic BFD for static routes.

# On DeviceA, bind the static route to the BFD session.

[~DeviceA] bfd
[*DeviceA-bfd] quit
[*DeviceA] ip route-static bfd 10.10.1.2 local-address 10.10.1.1
[*DeviceA] ip route-static 2.2.2.2 32 10.10.1.2 bfd enable
[*DeviceA] commit

# On DeviceB, bind the static route to the BFD session.

[~DeviceB] bfd
[*DeviceB-bfd] quit
[*DeviceB] ip route-static bfd 10.10.1.1 local-address 10.10.1.2
[*DeviceB] ip route-static 1.1.1.1 32 10.10.1.1 bfd enable
[*DeviceB] commit

Verify the configuration.

# After the preceding configuration, on DeviceA and DeviceB, you can view that the BFD session has been established and is Up and that the static routes have been bound to the BFD session.

Use the command output DeviceA as an example.

[~DeviceA] display bfd session all verbose
(w): State in WTR 
(*): State is invalid
------------------------------------------------------------------------------
  (Multi Hop) State : Up                    Name : dyn_8193
------------------------------------------------------------------------------
  Local Discriminator    : 8193             Remote Discriminator   : 8193
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Peer IP Address
  Bind Session Type      : Dynamic
  Bind Peer IP Address   : 10.10.1.2
  Bind Interface         : -
  Bind Source IP Address : 10.10.1.1
  FSM Board Id           : 0                TOS-EXP                : 7
  Min Tx Interval (ms)   : 50               Min Rx Interval (ms)   : 50
  Actual Tx Interval (ms): 50               Actual Rx Interval (ms): 50
  Local Detect Multi     : 3                Detect Interval (ms)   : 150
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 4784             TTL                    : 253
  Proc Interface Status  : Disable          Process PST            : Disable
  WTR Interval (ms)      : 0                Local Demand Mode      : Disable
  Active Multi           : 3
  Last Local Diagnostic  : No Diagnostic
  Bind Application       : STATICRT
  Session TX TmrID       : 0                Session Detect TmrID   : 0
  Session Init TmrID     : -                Session WTR TmrID      : -
  Session Echo Tx TmrID  : -
  Session Description    : -
------------------------------------------------------------------------------

     Total UP/DOWN Session Number : 1/0

Configuration Files

DeviceA configuration file

#
sysname DeviceA
#
bfd
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.10.1.1 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 7.7.7.7 255.255.255.0
#
interface LoopBack0
 ip address 1.1.1.1 255.255.255.255
#
ip route-static bfd 10.10.1.2 local-address 10.10.1.1
ip route-static 2.2.2.2 32 10.10.1.2 bfd enable
#
return

DeviceB configuration file

#
sysname DeviceB
#
bfd
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.10.1.2 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 8.8.8.8 255.255.255.0
#
interface LoopBack0
 ip address 2.2.2.2 255.255.255.255
#
ip route-static bfd 10.10.1.1 local-address 10.10.1.2
ip route-static 1.1.1.1 32 10.10.1.1 bfd enable
#
return