Dear all,
I have a senario where all the ibgp neighbors are stable. As soon as i peer one of the ibgp router to another router in different autonomous system, the ebgp peers begin to flap.
See error below:
*Mar 1 15:04:25.404: %BGP-3-NOTIFICATION: sent to neighbor 8.8.8.8 4/0 (hold time expired) 0 bytes
The ebgp router are directly connected via serial ports. Also, both serial ports have MTU of 1500.
Find sample config:
R6:
interface Serial0/0
ip address 10.10.68.6 255.255.255.0
clock rate 2000000
!
router ospf 10
log-adjacency-changes
redistribute bgp 3 subnets
network 6.6.6.6 0.0.0.0 area 0
network 10.10.56.0 0.0.0.255 area 0
network 10.10.67.0 0.0.0.255 area 0
network 10.10.68.0 0.0.0.255 area 0
!
router bgp 3
no synchronization
bgp log-neighbor-changes
bgp suppress-inactive
network 6.6.6.6 mask 255.255.255.255
network 10.10.56.0 mask 255.255.255.0
network 10.10.67.0 mask 255.255.255.0
redistribute ospf 10 metric 1
neighbor 3.3.3.3 remote-as 3
neighbor 3.3.3.3 update-source Loopback0
neighbor 3.3.3.3 next-hop-self
neighbor 4.4.4.4 remote-as 3
neighbor 4.4.4.4 update-source Loopback0
neighbor 4.4.4.4 next-hop-self
neighbor 5.5.5.5 remote-as 3
neighbor 5.5.5.5 update-source Loopback0
neighbor 5.5.5.5 next-hop-self
neighbor 7.7.7.7 remote-as 3
neighbor 7.7.7.7 update-source Loopback0
neighbor 7.7.7.7 next-hop-self
neighbor 8.8.8.8 remote-as 89
neighbor 8.8.8.8 ebgp-multihop 2
neighbor 8.8.8.8 update-source Loopback0
no auto-summary
R8:
interface Serial0/0
ip address 10.10.68.8 255.255.255.0
clock rate 2000000
!
router ospf 10
log-adjacency-changes
redistribute bgp 89 subnets
network 8.8.8.8 0.0.0.0 area 0
network 10.10.68.0 0.0.0.255 area 0
network 10.10.89.0 0.0.0.255 area 0
!
router bgp 89
no synchronization
bgp log-neighbor-changes
network 8.8.8.8 mask 255.255.255.255
network 10.10.68.0 mask 255.255.255.0
network 10.10.89.0 mask 255.255.255.0
redistribute ospf 10 metric 1
neighbor 6.6.6.6 remote-as 3
neighbor 6.6.6.6 ebgp-multihop 2
neighbor 6.6.6.6 update-source Loopback0
neighbor 9.9.9.9 remote-as 89
neighbor 9.9.9.9 update-source Loopback0
neighbor 9.9.9.9 next-hop-self
no auto-summary
Please, help explain how i can fix this unstable and flapping ebgp peers.
Regards,
Ethelbert
