Prerequisites: CCNP level skills.
Note!
BGP configuration based on Lab 108 (R4 loopbacks already advertised and aggregated).
Topology
Task 1
R4 is advertising the aggregate 40.0.0.0/14. Configure R4 so that it also advertises more specific prefixes as follows:
- 40.3.0.0/16 towards R1
- 40.1.0.0/16 towards R2
Task 1
R4 is advertising the aggregate 40.0.0.0/14. Configure R4 so that it also advertises more specific prefixes as follows:
- 40.3.0.0/16 towards R1
- 40.1.0.0/16 towards R2
Pic. 2 - Suppressed Routes on R4.
Pic. 3 - BGP Table on R5.
R4 Configuration:
!
ip prefix-list NET_40 seq 5 permit 40.0.0.0/8 le 16
ip prefix-list NET_44 seq 5 permit 44.4.0.0/16 le 19
ip prefix-list PFX_UNSUPPRESS_TO_R1 seq 5 permit 40.3.0.0/16
ip prefix-list PFX_UNSUPPRESS_TO_R2 seq 5 permit 40.1.0.0/16
ip prefix-list NET_44 seq 5 permit 44.4.0.0/16 le 19
ip prefix-list PFX_UNSUPPRESS_TO_R1 seq 5 permit 40.3.0.0/16
ip prefix-list PFX_UNSUPPRESS_TO_R2 seq 5 permit 40.1.0.0/16
!
route-map CONN_TO_BGP permit 10
match ip address prefix-list NET_40
!
route-map CONN_TO_BGP permit 20
match ip address prefix-list NET_44
!
route-map UNSUPPRESS_TO_R2 permit 10
match ip address prefix-list PFX_UNSUPPRESS_TO_R2
!
route-map UNSUPPRESS_TO_R1 permit 10
match ip address prefix-list PFX_UNSUPPRESS_TO_R1
!
router bgp 40
no synchronization
bgp router-id 172.16.104.4
bgp log-neighbor-changes
network 172.16.104.0 mask 255.255.255.0
aggregate-address 40.0.0.0 255.252.0.0 summary-only
aggregate-address 44.4.0.0 255.255.128.0
redistribute connected route-map CONN_TO_BGP
neighbor 10.1.14.1 remote-as 10
neighbor 10.1.14.1 unsuppress-map UNSUPPRESS_TO_R1
neighbor 10.1.24.2 remote-as 20
neighbor 10.1.24.2 unsuppress-map UNSUPPRESS_TO_R2
no auto-summary
match ip address prefix-list NET_40
!
route-map CONN_TO_BGP permit 20
match ip address prefix-list NET_44
!
route-map UNSUPPRESS_TO_R2 permit 10
match ip address prefix-list PFX_UNSUPPRESS_TO_R2
!
route-map UNSUPPRESS_TO_R1 permit 10
match ip address prefix-list PFX_UNSUPPRESS_TO_R1
!
router bgp 40
no synchronization
bgp router-id 172.16.104.4
bgp log-neighbor-changes
network 172.16.104.0 mask 255.255.255.0
aggregate-address 40.0.0.0 255.252.0.0 summary-only
aggregate-address 44.4.0.0 255.255.128.0
redistribute connected route-map CONN_TO_BGP
neighbor 10.1.14.1 remote-as 10
neighbor 10.1.14.1 unsuppress-map UNSUPPRESS_TO_R1
neighbor 10.1.24.2 remote-as 20
neighbor 10.1.24.2 unsuppress-map UNSUPPRESS_TO_R2
no auto-summary
!
Notice!
Applying this change does not require 'clear ip bgp * out' but it takes a moment to unsuppress the prefixes.
Verification:
Pic. 4 - BGP Table on R1 Received
from the Neighbor AS 40.
R1 receives the aggregate route 40.0.0./14 as well as unsuppressed route 40.3.0.0/16.
Pic. 5 - BGP Table on R2 Received
from the Neighbor AS 40.
Notice!
R2 receives the aggregate route 40.0.0./14 as well as unsuppressed route 40.1.0.0/16.