Topology:

Configurations:
R1#show run
Building configuration...
!
Version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname R1
!
!
!
ip subnet-zero
!
!
!
!
!
!
!
!
interface Loopback
ip address 1.1.1.1 255.255.255.0
no ip directed broadcast
!
!
interface Serial0/0
ip address 10.10.10.253 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
interface Serial0/1
ip address 10.10.20.253 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
interface Serial0/2
no ip address
no ip directed-broadcast
shutdown
!
interface Serial0/3
no ip address
no ip directed-broadcast
shutdown
!
router rip
version 2
network 1.0.0.0
network 10.0.0.0
no auto-summary
!
!
!
ip classless
no ip http server
!
!
!
!
!
line con 0
transport input none
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
no scheduler allocate
end
R1#
R2#show run
Building configuration...
!
Version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname R2
!
!
!
ip subnet-zero
!
!
!
!
!
!
!
!
!
interface Serial0/0
ip address 10.10.10.2 255.255.255.0
no ip directed-broadcast
!
interface Serial0/1
no ip address
no ip directed-broadcast
shutdown
!
interface Serial0/2
no ip address
no ip directed-broadcast
shutdown
!
interface Serial0/3
no ip address
no ip directed-broadcast
shutdown
!
interface FastEthernet1/0
ip address 100.1.1.2 255.255.255.0
no ip directed-broadcast
bandwidth 100000
!
router rip
version 2
network 10.0.0.0
network 100.0.0.0
no auto-summary
!
!
!
ip classless
no ip http server
!
!
!
!
!
line con 0
transport input none
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
no scheduler allocate
end
R2#
R3#show run
Building configuration...
!
Version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname R3
!
!
!
ip subnet-zero
!
!
!
!
!
!
!
!
!
interface Serial0/0
ip address 10.10.20.3 255.255.255.0
no ip directed-broadcast
!
interface Serial0/1
no ip address
no ip directed-broadcast
!
interface Serial0/2
no ip address
no ip directed-broadcast
shutdown
!
interface Serial0/3
no ip address
no ip directed-broadcast
shutdown
!
interface FastEthernet1/0
ip address 100.1.1.3 255.255.255.0
no ip directed-broadcast
bandwidth 100000
!
router rip
version 2
network 10.0.0.0
network 100.0.0.0
no auto-summary
!
!
!
ip classless
no ip http server
!
!
!
!
!
line con 0
transport input none
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
no scheduler allocate
end
R3#
PC4#show run
Building configuration...
!
Version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname PC4
!
!
!
ip subnet-zero
!
!
!
!
!
!
!
!
!
interface Serial0
no ip address
no ip directed-broadcast
shutdown
!
interface Serial1
no ip address
no ip directed-broadcast
shutdown
!
interface Ethernet0
ip address 100.1.1.4 255.255.255.0
no ip directed-broadcast
!
interface Bri0
no ip address
no ip directed-broadcast
shutdown
!
!
!
ip classless
no ip http server
!
!
!
!
!
line con 0
transport input none
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
no scheduler allocate
end
PC4#