实验环境GNS3 ios：c3725-ipbasek9-mz.124-11.t2.bin
拓扑：
这里在R2和R3上各开了loopback接口，并且IP地址都是A类IP1.0.0.0 网段地址，这样做的原因就是验证RIPv1是有类路由协议。
R1 R2 R3 的配置都差不多 ，下面只给出R1的配置：
hostname R1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
!
no ip domain lookup
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.2.1 255.255.255.0
duplex auto
speed auto
!
router rip
version 1
network 192.168.1.0
network 192.168.2.0
!
!
在R1上用show ip route可以看到路由情况
R1# show ip route
Codes: 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
Gateway of last resort is not set
R 1.0.0.0/8 [120/1] via 192.168.2.2, 00:00:02, FastEthernet0/1 //这里会发现本来应该是两条路由，这里变成
[120/1] via 192.168.1.2, 00:00:22, FastEthernet0/0 //了一条，因为RIP更新数据是不携带子网掩码
C 192.168.1.0/24 is directly connected, FastEthernet0/0
C 192.168.2.0/24 is directly connected, FastEthernet0/1
R1#
下面是在R2上show ip route的结果
R2#show ip route
Codes: 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
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.2.0 is directly connected, Loopback1
C 192.168.1.0/24 is directly connected, FastEthernet0/1 //这里没有1.1.1.0网段的路由是因为
R 192.168.2.0/24 [120/1] via 192.168.1.1, 00:00:17, FastEthernet0/1 //R1不会发送从相同接口学来的相同路R2# //由这叫水平分割
默认水平分割是开启的：开启命令：R2(config-if)#ip split-horizon
还有就是RIPv1更新地址是广播地址255.255.255.255，这和v2是有区别的
