R1上的配置：
R1(config)#int s1/0
R1(config-if)#ip add 12.0.0.1 255.255.255.0
R1(config-if)#clock rate 64000
R1(config-if)#no shu
R1(config)#int lo0
R1(config-if)#ip add 1.1.1.1 255.255.255.0
R1(config)#ip route 23.0.0.0 255.255.255.0 12.0.0.2
R1(config)#ip route 3.3.3.0 255.255.255.0 12.0.0.
R2上的配置：
R2(config)#int s1/2
R2(config-if)#ip add 12.0.0.2 255.255.255.0
R2(config-if)#no sh
R2(config)#int s1/0
R2(config-if)#ip add 23.0.0.2 255.255.255.0
R2(config-if)#no sh
R2(config)#ip route 1.1.1.0 255.255.255.0 12.0.0.1
R2(config)#ip route 3.3.3.0 255.255.255.0 23.0.0.3
R2的路由表：
R2#sho 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
在R1上作ping测试:
R1#ping 23.0.0.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 23.0.0.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/61/112 ms
R1#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 76/84/92 m
R3上的配置：
R3(config)#int s1/2
R3(config-if)#ip add 23.0.0.3 255.255.255.0
R3(config-if)#clock rate 64000
R3(config-if)#no sh
R3(config)#int lo0
R3(config-if)#ip add 3.3.3.3 255.255.255.0
R3(config)#ip route 1.1.1.0 255.255.255.0 23.0.0.2
R3(config)#ip route 12.0.0.0 255.255.255.0 23.0.0.2
R3的路由表：
R3#sho 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
S 1.1.1.0 [1/0] via 23.0.0.2
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
23.0.0.0/24 is subnetted, 1 subnets
C 23.0.0.0 is directly connected, Serial1/2
12.0.0.0/24 is subnetted, 1 subnets
S 12.0.0.0 [1/0] via 23.0.0.2
