Configuring BFD for BGP

Procedure
  1. Enable BFD support with the commandbfd.
  2. Create a BGP peer and initiate a connection to it with the commandneighbor remote-as.
  3. Enable BFD on a BGP interface with the commandneighbor fall-over bfd.
  4. Define an address family and activate it with the commandsaddress-familyandneighbor activate.
  5. 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 命令来改变它
    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.

  6. Review BFD configuration settings with the commandsshow bfd.

Example

Enabling BFD on a BGP interface.

switch#configswitch(config)#bfdswitch(config)#router bgp 100switch(config-router)#neighbor 10.1.231.2 remote-as 100switch(config-router)#neighbor 10.1.231.2 fall-over bfdswitch(config-router)#address-family ipv4-unicastswitch(config-router-ipv4-uc)#邻居10.1.231.2激活switch(config-router-ipv4-uc)#exitswitch(config-router)#exitswitch(config)#exitswitch#show ip bgp neighborsCodes: ^ 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