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

iosxr

Name	Type	Constraint	Mandatory	Default Value
devices	List	devices	No
device_groups	List	device_groups	No
global	Class	global	No

devices (iosxr)

Name	Type	Constraint	Mandatory	Default Value
configuration	Class	configuration	No

device_groups (iosxr)

Name	Type	Constraint	Mandatory	Default Value
configuration	Class	configuration	No

global (iosxr)

Name	Type	Constraint	Mandatory	Default Value
configuration	Class	configuration	No

configuration (iosxr.devices)

Name	Type	Constraint	Mandatory	Default Value
bfd	Class	bfd	No

bfd (iosxr.devices.configuration)

Name	Type	Constraint	Mandatory	Default Value
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
multipath_destinations	List	multipath_destinations	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	String		Yes

multipath_destinations (iosxr.devices.configuration.bfd)

Name	Type	Constraint	Mandatory	Default Value
address	IP		Yes
location	String		Yes

interfaces (iosxr.devices.configuration.bfd)

Name	Type	Constraint	Mandatory	Default Value
name	String		Yes
echo_disable	Boolean	true, false	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:
            - name: GigabitEthernet0/0/0/0
              echo_disable: true
              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

Example-5: Configure BFD multipath with locations and destinations.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1:57400
      configuration:
        hostname: router-1
        bfd:
          multipath_locations:
            - location: 0/0/CPU0
          multipath_destinations:
            - address: 10.1.1.1
              location: 0/0/CPU0
            - address: "2001:db1:1::1"
              location: 0/0/CPU0