Configuring BFD For OSPFv2

Prerequisites

  • OSPFv2 must be enabled.

  • ICMP must be disabled.

Procedure
  1. Enable BFD support with the command bfd.
  2. Enable BFD on all OSPF interfaces with the command bfd all-interfaces, or enable BFD on a specific interface with the command ip ospf bfd.
  3. For most deployments, the default values for the following features do not need to be changed. If your deployment requires different settings, change the default values with the indicated command:
    BFD setting Default value Command to change it
    Sets the BFD detection multiplier on an interface. 5 bfd detect-multiplier
    Sets the minimum time interval between received BFD echo packets. 500 milliseconds bfd min-echo-receive-interval
    Sets the minimum time interval between transmitted BFD control packets on an interface. 3000 milliseconds bfd min-transmit-interval

    Configuring the timers to be too aggressive (for example, setting a detection multiplier of 1) can sometimes lead to BFD session flaps depending upon traffic conditions.

  4. Review BFD configuration settings with the commands show bfd.

Examples

This example shows how to enable BFD on all OSPFv2 interfaces. 

switch# config
switch(config)# bfd
switch(config)# router ospf 1
switch(config-ospf-1)# area 1
switch(config-ospf-1)# bfd all-interfaces
switch(config-ospf-1)# exit
switch(config) router ospf 2
switch(config-ospf-2)# area 2
switch(config-ospf-2)# bfd all-interfaces
switch(config-ospf-2)# exit
switch(config)# interface 1/1/1
switch(config-if)# no shutdown
switch(config-if)# ip address 192.168.1.1/24
switch(config-if)# ip ospf 1 area 1
switch(config-if)# exit
switch(config)# interface 1/1/2
switch(config-if)# no shutdown
switch(config-if)# ip address 192.168.1.2/24
switch(config-if)# ip ospf 2 area 2
switch(config-if)# exit
switch(config)# exit
switch# show bfd
Admin status : Enabled
Echo source IP : 2.2.2.2
Statistics:
Total Number of Control Packets Transmitted : 42
Total Number of Control Packets Received : 42
Total Number of Control Packets Dropped : 0
Session Interface Source IP       Destination IP  Echo     State      Application
------- --------- --------------- --------------- -------- ---------- -----------
1       1/1/1     192.168.1.1     100.100.100.101 Enabled  Up         OSPF
2       1/2/2     192.168.1.2     10.1.5.6        Enabled  Up         OSPF

This example shows how to enable BFD on a specific OSPFv2 interface. 

switch# config
switch(config)# bfd
switch(config)# router ospf 1
switch(config-ospf-1)# area 1
switch(config-ospf-1)# exit
switch(config)# interface 1/1/1
switch(config-if)# no shutdown
switch(config-if)# ip address 192.168.1.1/24
switch(config-if)# ip ospf 1 area 1
switch(config-if)# ip ospf bfd
switch(config-if)# exit
switch(config)# exit
switch# show bfd session 1
BFD Session Information – Session 1
Min Tx Interval (sec) : 10
Min Rx Interval (sec) : 10
Min Echo Rx Interval (msec) : 700
Detect Multiplier : 3
Application : OSPF
Local Discriminator : 1
Remote Discriminator : 1
Echo : Enabled
Local Diagnostic : N/A
Remote Diagnostic: N/A
Flap count: 0
Internal state: Up
Interface Source IP       Destination IP  State      Pkt In   Pkt Out  Pkt Drop
--------- --------------- --------------- ---------- -------- -------- --------
1/1/1     192.168.1.1     100.100.100.101 Up         100      101      0