BFD

Bidirectional Forwarding Detection (BFD) is a lightweight protocol designed to provide fast failure detection for network paths between adjacent systems, enabling rapid convergence of routing protocols. It operates by sending periodic control packets between systems to detect path failures in milliseconds rather than the seconds or minutes required by traditional routing protocol hello mechanisms. BFD can be integrated with various routing protocols like OSPF, BGP, and EIGRP to dramatically improve network convergence times and overall network stability.

Diagram

Classes

configuration (iosxe.devices)

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

bfd (iosxe.devices.configuration)

Name	Type	Constraint	Mandatory
multi_hop_templates	List	`[multi_hop_templates]`	No
single_hop_templates	List	`[single_hop_templates]`	No
ipv4_maps	List	`[ipv4_maps]`	No
ipv6_maps	List	`[ipv6_maps]`	No
slow_timers	Integer	min: `1000`, max: `30000`	No

multi_hop_templates (iosxe.devices.configuration.bfd)

Name	Type	Constraint	Mandatory
name	String		Yes
echo	Boolean	`true`, `false`	No
interval_milliseconds_both	Integer		No
interval_milliseconds_min_tx	Integer		No
interval_milliseconds_min_rx	Integer		No
interval_milliseconds_multiplier	Integer	min: `3`, max: `50`	No
interval_microseconds	Boolean	`true`, `false`	No
interval_microseconds_both	Integer		No
interval_microseconds_min_tx	Integer		No
interval_microseconds_min_rx	Integer		No
interval_microseconds_multiplier	Integer		No
authentication_md5_keychain	String		No
authentication_meticulous_md5_keychain	String		No
authentication_meticulous_sha1_keychain	String		No
authentication_sha1_keychain	String		No
dampening_half_time	Integer	min: `1`, max: `30`	No
dampening_unsuppress_time	Integer	min: `1`, max: `18000`	No
dampening_suppress_time	Integer	min: `1`, max: `18000`	No
dampening_max_suppressing_time	Integer	min: `1`, max: `420`	No
dampening_threshold	Integer		No
dampening_down_monitoring	Boolean	`true`, `false`	No

single_hop_templates (iosxe.devices.configuration.bfd)

Name	Type	Constraint	Mandatory
name	String		Yes
echo	Boolean	`true`, `false`	No
interval_milliseconds_both	Integer		No
interval_milliseconds_min_tx	Integer		No
interval_milliseconds_min_rx	Integer		No
interval_milliseconds_multiplier	Integer		No
interval_microseconds_min_tx	Integer		No
interval_microseconds_min_rx	Integer		No
authentication_md5_keychain	String		No
authentication_meticulous_md5_keychain	String		No
authentication_meticulous_sha1_keychain	String		No
authentication_sha1_keychain	String		No
dampening_half_time	Integer	min: `1`, max: `30`	No
dampening_unsuppress_time	Integer	min: `1`, max: `18000`	No
dampening_suppress_time	Integer	min: `1`, max: `18000`	No
dampening_max_suppressing_time	Integer	min: `1`, max: `420`	No

ipv4_maps (iosxe.devices.configuration.bfd)

Name	Type	Mandatory
destination_vrf	String	No
destination_prefix	IP	Yes
source_vrf	String	No
source_prefix	IP	Yes
template	String	Yes

ipv6_maps (iosxe.devices.configuration.bfd)

Name	Type	Mandatory
destination_vrf	String	No
destination_prefix	IP	Yes
source_vrf	String	No
source_prefix	IP	Yes
template	String	Yes

Sample Configuration

The following CLI shows BFD configurations on IOS-XE devices.

bfd slow-timers 2000
bfd map ipv4 172.16.1.0/24 10.2.2.0/24 multi-hop-template-1
bfd map ipv4 vrf VRF-A 192.168.1.0/24 vrf VRF-B 10.1.1.0/24 multi-hop-template-1
bfd map ipv6 2001:DB8:1::/64 2001:DB8:2::/64 multi-hop-template-1
bfd map ipv6 vrf VRF-A 2001:DB8:1::/64 vrf VRF-B 2001:DB8:2::/64 multi-hop-template-1
!
bfd-template single-hop single-hop-template-1
 interval min-tx 100 min-rx 100 multiplier 3
 authentication md5 keychain md5-keychain-1
 dampening 5 300 600 10
 echo
!
bfd-template single-hop single-hop-template-2
 interval min-tx 150 min-rx 150 multiplier 4
 authentication sha-1 keychain sha1-keychain-1
!
bfd-template single-hop single-hop-separate-intervals
 interval min-tx 100 min-rx 150 multiplier 3
!
bfd-template multi-hop multi-hop-template-1
 interval min-tx 200 min-rx 200 multiplier 5
 authentication meticulous-md5 keychain meticulous-md5-keychain
!
bfd-template multi-hop multi-hop-md5-auth
 interval min-tx 150 min-rx 150 multiplier 4
 authentication md5 keychain md5-keychain-1
!
bfd-template multi-hop multi-hop-separate-intervals
 interval min-tx 150 min-rx 200 multiplier 4
!
bfd-template multi-hop multi-hop-dampening
 interval min-tx 200 min-rx 200 multiplier 5
 dampening 5 500 1000 10

Example YAML Code

iosxe:
  devices:
    - name: Device1
      configuration:
        bfd:
          slow_timers: 2000
          ipv4_maps:
            - destination_prefix: 172.16.1.0/24
              source_prefix: 10.2.2.0/24
              template: multi-hop-template-1
            - destination_vrf: VRF-A
              destination_prefix: 192.168.1.0/24
              source_vrf: VRF-B
              source_prefix: 10.1.1.0/24
              template: multi-hop-template-1
          ipv6_maps:
            - destination_prefix: 2001:db8:1::/64
              source_prefix: 2001:db8:2::/64
              template: multi-hop-template-1
            - destination_vrf: VRF-A
              destination_prefix: 2001:db8:1::/64
              source_vrf: VRF-B
              source_prefix: 2001:db8:2::/64
              template: multi-hop-template-1
          single_hop_templates:
            - name: single-hop-template-1
              echo: true
              interval_milliseconds_both: 100
              interval_milliseconds_multiplier: 3
              authentication_md5_keychain: md5-keychain-1
              dampening_half_time: 5
              dampening_unsuppress_time: 300
              dampening_suppress_time: 600
              dampening_max_suppressing_time: 10
            - name: single-hop-template-2
              interval_milliseconds_both: 150
              interval_milliseconds_multiplier: 4
              authentication_sha_1_keychain: sha1-keychain-1
            - name: single-hop-template-separate-intervals
              interval_milliseconds_min_tx: 100
              interval_milliseconds_min_rx: 150
              interval_milliseconds_multiplier: 3
          multi_hop_templates:
            - name: multi-hop-template-1
              interval_milliseconds_both: 200
              interval_milliseconds_multiplier: 5
              authentication_meticulous_md5_keychain: meticulous-md5-keychain
            - name: multi-hop-template-2
              interval_microseconds: true
              interval_microseconds_both: 100000
              interval_microseconds_multiplier: 4
              authentication_meticulous_sha1_keychain: meticulous-sha1-keychain
            - name: multi-hop-template-md5-auth
              interval_milliseconds_both: 150
              interval_milliseconds_multiplier: 4
              authentication_md5_keychain: md5-keychain-1
            - name: multi-hop-template-separate-intervals
              interval_milliseconds_min_tx: 150
              interval_milliseconds_min_rx: 200
              interval_milliseconds_multiplier: 4
            - name: multi-hop-template-dampening
              interval_milliseconds_both: 200
              interval_milliseconds_multiplier: 5
              dampening_half_time: 5
              dampening_unsuppress_time: 500
              dampening_suppress_time: 1000
              dampening_max_suppressing_time: 10