BGP active backup link scenario using BFD

[nwarchitect92]

BFDsessions between Juniper and FRR devices are stuck in DOWN or INIT state, despite BGP sessions being established and stable.
Juniper router (AS 200) and FRR (AS 100) with interfaces:

st0.25 → 25.25.25.1

st0.29 → 29.29.29.1

I am sharing FRR side stats as juniper is running fine with juniper.
Both BGP sessions are successfully established and prefixes are exchanged correctly. Despite correct configuration.
FRR# show bgp neighbors
show bgp neighbors
BGP neighbor is 25.25.25.1, remote AS 200, local AS 100, external link
BGP version 4, remote router ID 19.19.19.2, local router ID 192.168.201.155
BGP state = Established, up for 00:32:32
Last read 00:00:02, Last write 00:00:02
Hold time is 15, keepalive interval is 5 seconds
Configured hold time is 15, keepalive interval is 5 seconds
Neighbor capabilities:
4 Byte AS: advertised and received
AddPath:
IPv4 Unicast: RX advertised IPv4 Unicast
Route refresh: advertised and received(old & new)
Address Family IPv4 Unicast: advertised and received
Hostname Capability: advertised (name: bgpd,domain name: n/a) not received
Graceful Restart Capabilty: advertised and received
Remote Restart timer is 120 seconds
Address families by peer:
none
Graceful restart information:
End-of-RIB send: IPv4 Unicast
End-of-RIB received: IPv4 Unicast
Message statistics:
Inq depth is 0
Outq depth is 0
Sent Rcvd
Opens: 2 2
Notifications: 0 2
Updates: 6 4
Keepalives: 907 1004
Route Refresh: 0 0
Capability: 0 0
Total: 915 1012
Minimum time between advertisement runs is 0 seconds

For address family: IPv4 Unicast
Update group 1, subgroup 1
Packet Queue length 0
Community attribute sent to this neighbor(all)
Inbound path policy configured
Route map for incoming advertisements is *Primary
1 accepted prefixes

Connections established 2; dropped 1
Last reset 00:32:34, due to NOTIFICATION received (Cease/Other Configuration Change)
Local host: 25.25.25.2, Local port: 38262
Foreign host: 25.25.25.1, Foreign port: 179
Nexthop: 25.25.25.2
Nexthop global: ::
Nexthop local: ::
BGP connection: shared network
BGP Connect Retry Timer in Seconds: 120
Estimated round trip time: 3 ms
Read thread: on Write thread: on

BFD: Type: single hop
Detect Multiplier: 3, Min Rx interval: 300, Min Tx interval: 300
Status: Down, Last update: 0:00:32:34

BGP neighbor is 29.29.29.1, remote AS 200, local AS 100, external link
BGP version 4, remote router ID 19.19.19.2, local router ID 192.168.201.155
BGP state = Established, up for 00:31:53
Last read 00:00:01, Last write 00:00:03
Hold time is 15, keepalive interval is 5 seconds
Configured hold time is 15, keepalive interval is 5 seconds
Neighbor capabilities:
4 Byte AS: advertised and received
AddPath:
IPv4 Unicast: RX advertised IPv4 Unicast
Route refresh: advertised and received(old & new)
Address Family IPv4 Unicast: advertised and received
Hostname Capability: advertised (name: bgpd,domain name: n/a) not received
Graceful Restart Capabilty: advertised and received
Remote Restart timer is 120 seconds
Address families by peer:
none
Graceful restart information:
End-of-RIB send: IPv4 Unicast
End-of-RIB received: IPv4 Unicast
Message statistics:
Inq depth is 0
Outq depth is 0
Sent Rcvd
Opens: 2 2
Notifications: 0 2
Updates: 8 4
Keepalives: 906 1005
Route Refresh: 0 0
Capability: 0 0
Total: 916 1013
Minimum time between advertisement runs is 0 seconds

For address family: IPv4 Unicast
Update group 1, subgroup 1
Packet Queue length 0
Community attribute sent to this neighbor(all)
Inbound path policy configured
Route map for incoming advertisements is *Backup
1 accepted prefixes

Connections established 2; dropped 1
Last reset 00:31:55, due to NOTIFICATION received (Cease/Other Configuration Change)
Local host: 29.29.29.2, Local port: 38084
Foreign host: 29.29.29.1, Foreign port: 179
Nexthop: 29.29.29.2
Nexthop global: ::
Nexthop local: ::
BGP connection: shared network
BGP Connect Retry Timer in Seconds: 120
Estimated round trip time: 2 ms
Read thread: on Write thread: on

BFD: Type: single hop
Detect Multiplier: 3, Min Rx interval: 300, Min Tx interval: 300
Status: Down, Last update: 0:00:31:55

show bfd peer
BFD Peers:
peer 29.29.29.1 interface ips2
ID: 2
Remote ID: 0
Status: down
Downtime: 3 hour(s), 2 minute(s), 17 second(s)
Diagnostics: ok
Remote diagnostics: ok
Local timers:
Receive interval: 300ms
Transmission interval: 300ms
Echo transmission interval: disabled
Remote timers:
Receive interval: 0ms
Transmission interval: 0ms
Echo transmission interval: 0ms

peer 25.25.25.1 interface ips1
	ID: 1
	Remote ID: 0
	Status: down
	Downtime: 3 hour(s), 2 minute(s), 17 second(s)
	Diagnostics: ok
	Remote diagnostics: ok
	Local timers:
		Receive interval: 300ms
		Transmission interval: 300ms
		Echo transmission interval: disabled
	Remote timers:
		Receive interval: 0ms
		Transmission interval: 0ms
		Echo transmission interval: 0ms

FRR#
router bgp 100
bgp router-id 192.168.201.155
neighbor 25.25.25.1 remote-as 200
neighbor 25.25.25.1 bfd
neighbor 29.29.29.1 remote-as 200
neighbor 29.29.29.1 bfd
!
address-family ipv4 unicast
network 192.168.201.0/24
neighbor 25.25.25.1 route-map RT_OUT in
neighbor 29.29.29.1 route-map RT-Out-bkp in
exit-address-family
!
!
ip prefix-list PREFIX_BACKUP seq 5 permit 192.168.201.0/24
ip prefix-list PREFIX_MASTER seq 5 permit 192.168.201.0/24
!
route-map RT-Out-bkp permit 20
match ip address prefix-list PREFIX_BACKUP
set as-path prepend 100
!
route-map RT_OUT permit 10
match ip address prefix-list PREFIX_MASTER
!
line vty