Manually Injecting Routes into BGP

Manually Injecting Routes into BGP
Manually injecting routes into BGP enables you to decide the exact routes you want a BGP
speaker to advertise to its peers. The following command needs to be entered in router configuration
mode:
network network-address mask subnet-mask
network-address - the address of the network you want to advertise.
subnet-mask - the subnet mask of the network you want to advertise.
Refer to Figure 8.15.
In this scenario, we will configure eBGP between routers R2 and R3. The loopback addresses
of R2 and R3 will be used for the BGP session. R2 and R3 are running an IGP between them
containing only the loopback addresses. R1 and R2 are running an IGP between them. So R2
knows about the Ethernet segment on R1. R1 will not run BGP. We want R2 to advertise its
connection to R1, and we also want R2 to advertise the Ethernet segment on R1 to R3. We want
R3 to advertise its Ethernet segment to R2. At this point, we will go ahead and enable BGP on
Configuring BGP 269
R2 and R3. We will also set the update source and eBGP multihop information on R2 and R3.
R2’s loopback interface number is 0, and the address is 2.2.2.2. R3’s loopback interface number
is 0, and the address is 3.3.3.3:
R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#router bgp 100
R2(config-router)#neighbor 3.3.3.3 remote-as 200
R2(config-router)#neighbor 3.3.3.3 update-source Lo0
R2(config-router)#neighbor 3.3.3.3 ebg-multihop
R2(config-router)#^Z
R2#
R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#router bgp 200
R3(config-router)#neighbor 2.2.2.2 remote-as 100
R3(config-router)#neighbor 2.2.2.2 update-source Lo0
R3(config-router)#neighbor 2.2.2.2 ebg-multihop
R3(config-router)#^Z
R3#