--R1--------R2--------R3---
                              RIPV1     RIPV1     RIPV2    
R1#show running-config
!
interface Loopback0
 ip address 10.0.0.1 255.0.0.0
!
interface Serial1/1
 ip address 20.0.0.1 255.0.0.0
 serial restart-delay 0
!
router rip
 network 10.0.0.0
 network 20.0.0.0

R2#show running-config
!
interface Serial1/0
 ip address 20.0.0.2 255.0.0.0
 serial restart-delay 0
!
interface Serial1/1
 ip address 30.0.0.1 255.0.0.0
 serial restart-delay 0
!
router rip
 network 20.0.0.0
 network 30.0.0.0
R3#show running-config
interface Loopback0
 ip address 40.0.0.1 255.0.0.0
!
interface Serial1/0
 ip address 30.0.0.2 255.0.0.0
 ip rip send version 1 2
 ip rip receive version 1 2
 serial restart-delay 0
!
router rip
 version 2
 network 30.0.0.0
 network 40.0.0.0
!
 
 
R1#show ip rou
Gateway of last resort is not set
C    20.0.0.0/8 is directly connected, Serial1/1
R    40.0.0.0/8 [120/2] via 20.0.0.2, 00:00:03, Serial1/1
C    10.0.0.0/8 is directly connected, Loopback0
R    30.0.0.0/8 [120/1] via 20.0.0.2, 00:00:03, Serial1/1
R2#show ip route
Gateway of last resort is not set
C    20.0.0.0/8 is directly connected, Serial1/0
R    40.0.0.0/8 [120/1] via 30.0.0.2, 00:00:07, Serial1/1
R    10.0.0.0/8 [120/1] via 20.0.0.1, 00:00:12, Serial1/0
C    30.0.0.0/8 is directly connected, Serial1/1
R3#show ip rou
Gateway of last resort is not set
R    20.0.0.0/8 [120/1] via 30.0.0.1, 00:00:00, Serial1/0
C    40.0.0.0/8 is directly connected, Loopback0
R    10.0.0.0/8 [120/2] via 30.0.0.1, 00:00:00, Serial1/0
C    30.0.0.0/8 is directly connected, Serial1/0