Configuring BFD for BGP

Procedure

Enable BFD support with the command bfd.
Enable BFD on a BGP interface with the command neighbor fall-over bfd.

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, detect-multiplier of 1) can sometimes lead to BFD session flaps depending upon traffic conditions.

Review BFD configuration settings with the commands show bfd.

Example

Enabling BFD on a BGP interface.

switch# config
switch(config)# bfd
switch(config)# router bgp 100
switch(config-router)# neighbor 1.1.1.1 fall-over bfd
switch(config-router)# neighbor PG fall-over bfd
switch# show ip bgp neighbors
Codes: ^ Inherited from peer-group

VRF : default
BGP Neighbor 9.0.0.1 (External)
    Description         :
    Peer-group          :

    Remote Router Id    : 0.0.0.0            Local Router Id    : (null)
    Remote AS           : 100                Local AS           : 100
    Remote Port         : 0                  Local Port         : 0
    State               : Idle               Admin Status       : Up
    Conn. Established   : 0                  Conn. Dropped      : 0
    Passive             : No                 Update-Source      :
    Cfg. Hold Time      : 180                Cfg. Keep Alive    : 60
    Neg. Hold Time      : 0                  Neg. Keep Alive    : 0
    Up/Down Time        : 00h:00m:00s        Alt. Local-AS      : 0
    Local-AS Prepend    : No
    Fall-over           : No                 BFD                : Enabled
    Password            :
    Last Err Sent       : No Error
    Last SubErr Sent    : No Error
    Last Err Rcvd       : No Error
    Last SubErr Rcvd    : No Error

    Graceful-Restart    : Enabled            Rt. Reflect. Client: No
    Gr. Restart Time    : 120                Gr. Stalepath Time : 150
    Max. Prefix         : 0                  Send Community     :
    Allow-AS in         : 0                  Remove Private-AS  : No
    Advt. Interval      : 30                 TTL                : 255
    Soft Reconfig In    :                    Local Cluster-ID   :
    Nexthop-Self        :                    Default-Originate  :
    Weight              : 0
    TTL Security Hops   : 0

    Routemap In         :
    Routemap Out        :

  Message statistics:
                      Sent     Rcvd
                      -----    ------
    Open                  0         0
    Notification          0         0
    Updates               0         0
    Keepalives            0         0
    Route Refresh         0         0
    Total                 0         0

    Capability         Advertised      Received
    ---------------------------------------------
    Route Refresh        No               No
    Graceful Restart     No               No
    Four Octet ASN       No               No