! FRR configuration for ToR-A in Rack1
! ToR loopback: 10.254.1.11/32
! Host links: 172.16.1.0/25 (hosts 1-64)
! Spine links: 172.17.x.x/31

frr version 8.5.1
frr defaults traditional
hostname tor-a-rack1
log syslog informational
service integrated-vtysh-config

! Enable BGP
router bgp 65000
 bgp router-id 10.254.1.11
 no bgp ebgp-requires-policy
 no bgp default ipv4-unicast

 ! Host neighbors (example for first few hosts)
 ! In production, use peer-group or automation
 neighbor 172.16.1.10 remote-as 65001
 neighbor 172.16.1.10 description host-rack1-11
 neighbor 172.16.1.10 ebgp-multihop 2
 neighbor 172.16.1.10 timers 3 10

 neighbor 172.16.1.12 remote-as 65002
 neighbor 172.16.1.12 description host-rack1-12
 neighbor 172.16.1.12 ebgp-multihop 2
 neighbor 172.16.1.12 timers 3 10

 ! Spine neighbors (example - adjust based on your spine count)
 neighbor 172.17.1.1 remote-as 65010
 neighbor 172.17.1.1 description spine-1
 neighbor 172.17.1.1 ebgp-multihop 2
 neighbor 172.17.1.1 timers 3 10

 neighbor 172.17.1.2 remote-as 65010
 neighbor 172.17.1.2 description spine-2
 neighbor 172.17.1.2 ebgp-multihop 2
 neighbor 172.17.1.2 timers 3 10

 ! Advertise learned host routes to spines
 address-family ipv4 unicast
  ! Activate all neighbors
  neighbor 172.16.1.10 activate
  neighbor 172.16.1.12 activate
  neighbor 172.17.1.1 activate
  neighbor 172.17.1.2 activate

  ! Advertise host /32s learned from hosts to spines
  neighbor 172.17.1.1 route-map ADVERTISE-HOSTS out
  neighbor 172.17.1.2 route-map ADVERTISE-HOSTS out

  ! Allow all routes from hosts (they only send their /32)
  neighbor 172.16.1.10 route-map PERMIT-ALL in
  neighbor 172.16.1.12 route-map PERMIT-ALL in
 exit-address-family

! Route maps
route-map ADVERTISE-HOSTS permit 10
 match ip address prefix-list HOST-LOOPBACKS

route-map PERMIT-ALL permit 10

! Prefix list for host loopbacks (10.255.1.0/24 for Rack1)
ip prefix-list HOST-LOOPBACKS seq 5 permit 10.255.1.0/24 ge 32

! Advertise ToR loopback
ip route 10.254.1.11/32 lo

line vty