第一步、预配置
r1(config)#int s3/0
r1(config-if)#ip add 12.0.0.1 255.255.255.0
r1(config-if)#no sh
r1(config-if)#exit
r1(config)#int lo0
r1(config-if)#ip add 1.1.1.1 255.255.255.0
r1(config-if)#exit

r2(config)#int s3/0
r2(config-if)#ip add 12.0.0.2 255.255.255.0
r2(config-if)#no sh
r2(config-if)#exit
r2(config)#int lo0
r2(config-if)#ip add 2.2.2.2 255.255.255.0
r2(config-if)#exit

r3(config)#int lo0
r3(config-if)#ip add 3.3.3.3 255.255.255.0
r3(config-if)#exit
r3(config)#int s3/0
r3(config-if)#ip add 12.0.0.3 255.255.255.0
r3(config-if)#no sh

第二步、配置帧中继
r1(config-if)#en fr
r1(config-if)#no frame-relay inv
r1(config-if)#fram
r1(config-if)#frame-relay map ip 12.0.0.2 102 b
r1(config-if)#frame-relay map ip 12.0.0.3 103 b
r1(config-if)#

r2(config-if)#en fr
r2(config-if)#no frame-relay inv
r2(config-if)#fram
r2(config-if)#frame-relay map ip 12.0.0.1 201 b
r2(config-if)#frame-relay map ip 12.0.0.3 201 b
r2(config-if)#exit

r3(config-if)#en fr
r3(config-if)#no frame-relay inv
r3(config-if)#fram
r3(config-if)#frame-relay map ip 12.0.0.1 301 b
r3(config-if)#frame-relay map ip 12.0.0.2 301 b
r3(config-if)#exit

第三步、配置ospf
r1(config)#router ospf 100
r1(config-router)#net 12.0.0.0 0.0.0.255 a 0
r1(config-router)#net 1.1.1.0 0.0.0.255 a 0

r2(config)#router ospf 100
r2(config-router)#net 12.0.0.0 0.0.0.255 a 0
r2(config-router)#net 2.2.2.0 0.0.0.255 a 0
r2(config-router)#end

r3(config)#router ospf 100
r3(config-router)#net 12.0.0.0 0.0.0.255 a 0
r3(config-router)#net 3.3.3.0 0.0.0.255 a 0
r3(config-router)#

第四步、在r1上定义邻居
r1(config-router)#neighbor 12.0.0.2
r1(config-router)#neighbor 12.0.0.3

第五步、验证
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

1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/65] via 12.0.0.2, 00:00:18, Serial3/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 12.0.0.3, 00:00:18, Serial3/0
12.0.0.0/24 is subnetted, 1 subnets
C 12.0.0.0 is directly connected, Serial3/0
r1#

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

1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/65] via 12.0.0.1, 00:00:27, Serial3/0
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 12.0.0.3, 00:00:27, Serial3/0
12.0.0.0/24 is subnetted, 1 subnets
C 12.0.0.0 is directly connected, Serial3/0

r3#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

1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/65] via 12.0.0.1, 00:00:36, Serial3/0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/65] via 12.0.0.2, 00:00:36, Serial3/0
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
12.0.0.0/24 is subnetted, 1 subnets
C 12.0.0.0 is directly connected, Serial3/0