Information Technology Reference
In-Depth Information
Figure 4-2
Conditional Advertisement in a Primary-Backup Scenario
Backup
Primary
R2
R3
172.16.0.0/16
AS 200
AS 300
.2
.3
172.16.2.0/24
192.168.12.0/24
192.168.13.0/24
.1
.1
AS 100
R1
172.16.1.0/24
Example 4-14
Sample BGP Configuration for Conditional Advertisement on R1
router bgp 100
network 172.16.1.0 mask 255.255.255.0
neighbor 192.168.12.2 remote-as 200
neighbor 192.168.12.2 advertise-map AS200-out non-exist-map AS300-in
neighbor 192.168.13.3 remote-as 300
neighbor 192.168.13.3 route-map Set-comm in
!
ip community-list 1 permit 100:300
ip prefix-list AS300-track seq 5 permit 172.16.2.0/24
ip prefix-list Local-prefix seq 5 permit 172.16.1.0/24
!
route-map AS300-in permit 10
match ip address prefix-list AS300-track
match community 1
!
route-map Set-comm permit 10
set community 100:300
!
route-map AS200-out permit 10
match ip address prefix-list Local-prefix
When prefix 172.16.2.0/24 is present in R1's BGP RIB, 172.16.1.0/24 is not advertised to
R2, as shown in Examples 4-15 and 4-16.
