eBGP & full mesh iBGP route exchange issue.

[saran sathiamurthy]

Hello,

I am new to BGP, i am trying lab scenario similar to the one found in Cisco support site (http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/26634-bgp-toc.html#synch). However its not going as planned. Below is the topology diagram and the router configs.

I am unable to establish communication between R4 & R5. Using Full mesh iBGP, i want the achieve the result instead of redistribution.

And When issue command " show ip bgp " , Nothing is displayed.

Any pointers would be greatly appreciated.

R4#sh run | s bgp
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 neighbor 10.10.10.2 remote-as 200
 no auto-summary

R4#sh ip int bri | e un
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            10.10.10.1      YES manual up                    up

R1#sh run | s router
router ospf 1
 log-adjacency-changes
 network 20.20.1.1 0.0.0.0 area 0
router bgp 200
 no synchronization
 bgp log-neighbor-changes
 neighbor 10.10.10.1 remote-as 100
 neighbor 20.20.1.2 remote-as 200
 neighbor 20.20.2.1 remote-as 200
 no auto-summary

R1#sh ip int bri | e un
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            10.10.10.2      YES manual up                    up
FastEthernet0/1            20.20.1.1       YES manual up                    up

R1#sh ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
20.20.2.2         0   FULL/  -        00:00:34    20.20.1.2       FastEthernet0/1

R3# sh run | s rout
router ospf 1
 log-adjacency-changes
 network 20.20.0.0 0.0.255.255 area 0
router bgp 200
 no synchronization
 bgp log-neighbor-changes
 neighbor 20.20.1.1 remote-as 200
 neighbor 20.20.2.1 remote-as 200
 no auto-summary

R3#sh ip int bri | e un
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/1            20.20.1.2       YES manual up                    up
FastEthernet1/0            20.20.2.2       YES manual up                    up

R3#sh ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
30.30.30.2        0   FULL/  -        00:00:39    20.20.2.1       FastEthernet1/0
20.20.1.1         0   FULL/  -        00:00:32    20.20.1.1       FastEthernet0/1

R2#sh run | s rout
router ospf 1
 log-adjacency-changes
 network 20.20.2.1 0.0.0.0 area 0
router bgp 200
 no synchronization
 bgp log-neighbor-changes
 neighbor 20.20.1.1 remote-as 200
 neighbor 20.20.2.2 remote-as 200
 neighbor 30.30.30.1 remote-as 300
 no auto-summary

R2#sh ip int bri | e un
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet1/0            20.20.2.1       YES manual up                    up
FastEthernet2/0            30.30.30.2      YES manual up                    up

R2#sh ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
20.20.2.2         0   FULL/  -        00:00:30    20.20.2.2       FastEthernet1/0

R5# sh run | s bgp
router bgp 300
 no synchronization
 bgp log-neighbor-changes
 neighbor 30.30.30.2 remote-as 200
 no auto-summary

R5#sh ip int bri | e un
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet2/0            30.30.30.1      YES manual up                    up

Thank You

Regards

Saran

[milan.kulik]

Hi, you need to advertise some subnets by BGP. Try R4# conf t router bgp 100 redistribute connected or network 10.10.10.0 mask 255.255.255.0 BR, Milan

[Vignesh Rajendran Praveen]

Hi Saran,

You need to add network statements under BGP on both R4 & R5 routers for networks 10.10.10.0 & 30.30.30.0 respectively.

***********Plz do rate this post if you found it helpful*************************

Thanks & Regards,

Vignesh R P

[Naren K]

Saran,

You can achieve your objective using below method -

eBGP peering between R4 and R5 can be established on non-directly connected or loopback interface IP.

In AS 200 (iBGP peering will be stablished) you will need to activate route reflector client to ensure iBGP peer share the routes received from another iBGP peer.

Advertised networks / IP's you wanted to be reachable from R4 and R5.

You need to ensure IP address on you need to establish peering should vice-versa reachable from R4 and R5 routers.

Happy to help

Rate if you find answer is helpful.