Configuring BFD for BGP

Context

BGP periodically sends Keepalive messages to its peers to detect the status of its peers. It takes more than 1 second for this detection mechanism to detect a fault. When data is transmitted at gigabit rates, long-time fault detection will cause packet loss and cannot meet high reliability requirements of carrier-class networks. BFD for BGP can solve this problem. BFD is a millisecond-level fault detection mechanism. It can fast detect faults on the link between BGP neighbors. Therefore, BFD speeds up BGP route convergence, ensures fast link switching, and reduces traffic loss.

When a peer joins a peer group on which BFD is enabled, BFD also takes effect on the peer and a BFD session is created on the peer. To prevent BFD from taking effect on the peer, run the peer bfd block command.

By default, Huawei devices establish multi-hop IBGP sessions with each other. When a Huawei device communicates with a non-Huawei device that establishes a single-hop IBGP session by default, you are advised to configure only association between IGP and BFD or association between IBGP and BFD.

Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support BFD for BGP.

Procedure

Run system-view
The system view is displayed.
Run bfd
Global BFD is enabled on the local device.
Run quit
Return to the system view.
Run bgp { as-number-plain | as-number-dot }
The BGP view is displayed.
Run peer { group-name | ipv4-address | ipv6-address } bfd enable [ single-hop-prefer ]
BFD is configured for the peer or peer group, and default BFD parameters are used to establish BFD sessions.

single-hop-prefer takes effect only on IBGP peers. By default, if single-hop-prefer is not specified, multi-hop sessions are established between direct IBGP peers (Huawei devices). To interconnect a Huawei device and a non-Huawei device that defaults the sessions between IBGP peers to single-hop, configure single-hop-prefer in the command.

If BFD is configured for a peer group, BFD sessions are created for the peers on which the peer bfd block command is not used.
Run peer { group-name | ipv4-address | ipv6-address } bfd { min-tx-interval min-tx-interval | min-rx-interval min-rx-interval | detect-multiplier multiplier | wtr wtr-value } ^*
BFD session parameters are configured.
(Optional) Run peer { ipv4-address | ipv6-address } bfd block
The peer is disabled from inheriting the BFD function of the peer group to which the peer belongs.
- BFD sessions are established when they are in Established state.
- If BFD parameters are configured on a peer, BFD sessions are established using these parameters.
- The peer { ipv4-address | ipv6-address } bfd block and peer { group-name | ipv4-address | ipv6-address } bfd enable [ single-hop-prefer ] commands are mutually exclusive.

Verifying the Configuration

Run the display bgp bfd session { [ vpnv4 vpn-instance vpn-instance-name ] peer ipv4-address | all } command to check information about the BFD sessions established between BGP peers.
Run the display bgp [ vpnv4 vpn-instance vpn-instance-name ] peer [ [ ipv4-address ] verbose ] command to check information about BGP peers.
Run the display bgp group [ group-name ] command to check information about the specified BGP peer group.
Run the display bgp vpnv4 { all | vpn-instance vpn-instance-name } group [ group-name ] command to check information about the BGP VPNv4 peer group.