Basic route reflection

Basic route reflection
AS 100
R2 R3
R1
R4
Overcoming Scalability Limitations of iBGP
289
The first task is to configure iBGP on each of the routers:
R1#
conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#
router bgp 100
R1(config-router)#
no synchronization
R1(config-router)#
neighbor 2.2.2.2 remote-as 100
R1(config-router)#
neighbor 2.2.2.2 update-source Lo0
R1(config-router)#
neighbor 3.3.3.3 remote-as 100
R1(config-router)#
neighbor 3.3.3.3 update-source Lo0
R1(config-router)#
neighbor 4.4.4.4 remote-as 100
R1(config-router)#
neighbor 4.4.4.4 update-source Lo0
R1(config-router)#
^Z
R1#
R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#router bgp 100
R2(config-router)#no synchronization
R2(config-router)#neighbor 1.1.1.1 remote-as 100
R2(config-router)#neighbor 1.1.1.1 update-source Lo0
R2(config-router)#^Z
R2#
R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#router bgp 100
R3(config-router)#no synchronization
R3(config-router)#neighbor 1.1.1.1 remote-as 100
R3(config-router)#neighbor 1.1.1.1 update-source Lo0
R3(config-router)#^Z
R3#
R4#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R4(config)#router bgp 100
R4(config-router)#no synchronization
R4(config-router)#neighbor 1.1.1.1 remote-as 100
R4(config-router)#neighbor 1.1.1.1 update-source Lo0
R4(config-router)#^Z
R4#
290 Chapter 9  Advanced Border Gateway Protocol
At this point, this network will not work. We need to configure the route reflector:
R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#router bgp 100
R1(config-router)#neighbor 2.2.2.2 route-reflector-client
R1(config-router)#neighbor 3.3.3.3 route-reflector-client
R1(config-router)#neighbor 4.4.4.4 route-reflector-client
R1(config-router)#^Z
R1#
That’s all there is to configuring basic iBGP route reflection. It’s important to note that additional
configuration takes place only on the server. The client’s configuration actually tends to
undergo a reduction in its configuration, because neighbor statements to other clients in the
cluster are no longer used. When configuring multiple route reflectors in a cluster, we need to
assign each of the route reflectors the cluster ID for the cluster. The cluster ID can be assigned
by issuing the following command in router configuration mode:
bgp cluster-id cluster-ID
cluster-ID - The ID for the cluster.
We’re now going to implement a cluster with multiple route reflectors. Refer to Figure 9.