使用前面的拓扑
 
hostname R1
interface Loopback0
 ip address 1.1.1.1 255.255.255.255
!
interface Serial0.1 point-to-point
 ip address 192.168.1.1 255.255.255.0
 frame-relay interface-dlci 100  //必须在每一个子接口指定dlci号
!
interface Serial0.2 point-to-point
 ip address 192.168.2.1 255.255.255.0
 frame-relay interface-dlci 200  //必须在每一个子接口指定dlci号
router ospf 1
 network 1.1.1.1 0.0.0.0 area 0
 network 192.168.1.0 0.0.0.255 area 0
 network 192.168.2.0 0.0.0.255 area 0

hostname R2
!
interface Loopback0
 ip address 2.2.2.2 255.255.255.255
interface Serial1
 ip address 192.168.1.2 255.255.255.0
 encapsulation frame-relay
 frame-relay map ip 192.168.1.1 100 broadcast
!
router ospf 1
 network 2.2.2.2 0.0.0.0 area 0
 network 192.168.1.0 0.0.0.255 area 0
!
hostname R3
no ip domain-lookup
!
interface Loopback0
 ip address 3.3.3.3 255.255.255.255
!
interface Serial1
 ip address 192.168.2.2 255.255.255.0
 encapsulation frame-relay
 frame-relay map ip 192.168.2.1 200 broadcast
!
router ospf 1
 network 3.3.3.3 0.0.0.0 area 0
 network 192.168.2.0 0.0.0.255 area 0