#on router 4

hostname R4
int f0/0
ip address 156.10.0.1 255.255.255.0
no shutdown

int f0/1
ip address 156.20.0.1 255.255.255.0
no shutdown

int f1/0
ip address 166.10.0.1 255.255.255.0
no shutdown

router bgp 200
bgp router-id 4.4.4.4
neighbor 156.10.0.2 remote-as 100
neighbor 156.20.0.2 remote-as 100
network 166.10.0.0 mask 255.255.255.0

#on router 5

hostname R5
int f0/0
ip address 156.10.0.2 255.255.255.0
no shutdown

int f0/1
ip address 10.0.0.1 255.255.255.0
no shutdown

int f1/0
ip address 176.10.0.1 255.255.255.0
no shutdown

router bgp 100
bgp router-id 5.5.5.5
neighbor 156.10.0.1 remote-as 200
neighbor 10.0.0.2 remote-as 100
neighbor 10.0.0.2 next-hop-self
network 176.10.0.0 mask 255.255.255.0

#on router 6

hostname R6
int f0/0
ip address 156.20.0.2 255.255.255.0
no shutdown

int f0/1
ip address 10.0.0.2 255.255.255.0
no shutdown

int f1/0
ip address 186.10.0.1 255.255.255.0
no shutdown

router bgp 100
bgp router-id 6.6.6.6
neighbor 156.20.0.1 remote-as 200
neighbor 10.0.0.1 remote-as 100
neighbor 10.0.0.1 next-hop-self
network 186.10.0.0 mask 255.255.255.0