BFD

BFD is a protocol used to detect faults between two forwarding engines connected by a link. On IOS-XR, BFD provides sub-second failure detection for routing protocols such as BGP, IS-IS, and OSPF, enabling faster convergence than protocol-native keepalive timers. It supports single-hop, multi-hop, and bundle-member sessions with configurable dampening to prevent route flapping during unstable link conditions.

Diagram

Classes

configuration (iosxr.devices)

Name	Type	Constraint	Mandatory	Default Value
bfd	Class	`[bfd]`	No

bfd (iosxr.devices.configuration)

Name	Type	Constraint	Mandatory
echo_disable	Boolean	`true`, `false`	No
echo_latency_detect	Boolean	`true`, `false`	No
echo_latency_detect_percentage	Integer	min: `100`, max: `250`	No
echo_latency_detect_count	Integer	min: `1`, max: `10`	No
echo_startup_validate_force	Boolean	`true`, `false`	No
echo_ipv4_source	IP		No
echo_ipv4_bundle_per_member_minimum_interval	Integer	min: `15`, max: `2000`	No
trap_singlehop_pre_mapped	Boolean	`true`, `false`	No
multipath_locations	List	`[multipath_locations]`	No
multihop_ttl_drop_threshold	Integer	min: `0`, max: `254`	No
dampening_initial_wait	Integer	min: `1`, max: `3600000`	No
dampening_secondary_wait	Integer	min: `1`, max: `3600000`	No
dampening_maximum_wait	Integer	min: `1`, max: `3600000`	No
dampening_threshold	Integer	min: `60000`, max: `3600000`	No
dampening_extensions_down_monitoring	Boolean	`true`, `false`	No
dampening_disable	Boolean	`true`, `false`	No
dampening_bundle_member_l3_only_mode	Boolean	`true`, `false`	No
dampening_bundle_member_initial_wait	Integer	min: `1`, max: `518400000`	No
dampening_bundle_member_secondary_wait	Integer	min: `1`, max: `518400000`	No
dampening_bundle_member_maximum_wait	Integer	min: `1`, max: `518400000`	No
bundle_coexistence_bob_blb	Choice	`inherit`, `logical`	No
ipv6_checksum_disable	Boolean	`true`, `false`	No
interfaces	List	`[interfaces]`	No

multipath_locations (iosxr.devices.configuration.bfd)

Name	Type	Constraint	Mandatory	Default Value
location_id	String		Yes

interfaces (iosxr.devices.configuration.bfd)

Name	Type	Constraint	Mandatory
interface_name	String		Yes
echo_disable	Choice	`disable`, `enable`	No
echo_ipv4_source	IP		No
ipv6_checksum_disable	Boolean	`true`, `false`	No
disable	Boolean	`true`, `false`	No
local_address	IP		No
tx_interval	Integer	min: `3000`, max: `30000000`	No
rx_interval	Integer	min: `3000`, max: `30000000`	No
multiplier	Integer	min: `2`, max: `50`	No

Example YAML Code:

Example-1: Configure BFD with echo latency detection.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        hostname: router-1
        bfd:
          echo_latency_detect_percentage: 200
          echo_latency_detect_count: 10
          echo_startup_validate_force: true

Example-2: Configure BFD with echo IPv4 source and trap settings.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        hostname: router-1
        bfd:
          echo_ipv4_source: 10.1.1.1
          echo_ipv4_bundle_per_member_minimum_interval: 200
          trap_singlehop_pre_mapped: true

Example-3: Configure BFD dampening settings.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        hostname: router-1
        bfd:
          dampening_initial_wait: 3600
          dampening_secondary_wait: 3200
          dampening_maximum_wait: 3100
          dampening_threshold: 60000
          dampening_extensions_down_monitoring: true

Example-4: Configure BFD with interface-specific settings.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        hostname: router-1
        bfd:
          bundle_coexistence_bob_blb: "inherit"
          ipv6_checksum_disable: true
          interfaces:
            - interface_name: GigabitEthernet0/0/0/0
              echo_ipv4_source: 12.1.1.1
              ipv6_checksum_disable: true
              local_address: 12.1.1.1
              tx_interval: 300000
              rx_interval: 300000
              multiplier: 40