How to configure RIP V1 on Cisco Routers using GNS3?

RIP V1 : 

1. Rip v1 is classfull by default so it don't send subnet mask information with route updates.
2. To enable Rip v1 we have to go inside rip process and type version 1 .
3. Rip v1 don't support VLSM ( variable length subnet mask ) .

Commands : 

R1(config)#router rip
R1(config-router)#version 1
R1(config-router)#network 12.0.0.0
R1(config-router)#network 1.0.0.0
R1(config-router)#exit

R2(config)#router rip
R2(config-router)#version 1
R2(config-router)#network 12.0.0.0
R2(config-router)#network 2.0.0.0
R2(config-router)#exit
R2(config)#

Now to see Routes on R1 : 

R1#show ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      1.0.0.0/32 is subnetted, 1 subnets
C        1.1.1.1 is directly connected, Loopback1
R     2.0.0.0/8 [120/1] via 12.0.0.2, 00:00:28, FastEthernet0/0
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.0.0.0/8 is directly connected, FastEthernet0/0
L        12.0.0.1/32 is directly connected, FastEthernet0/0
 

Now to see routing table on R2 : 

R2#show ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

R     1.0.0.0/8 [120/1] via 12.0.0.1, 00:00:08, FastEthernet0/0
      2.0.0.0/32 is subnetted, 1 subnets
C        2.2.2.2 is directly connected, Loopback1
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.0.0.0/8 is directly connected, FastEthernet0/0
L        12.0.0.2/32 is directly connected, FastEthernet0/0