环境描述：
4台路由器，其中R2用来模拟帧中继云；R1的S0/0连接R2的S0/0，R3的S0/0连接R2的S0/1，R4的S0/0连接R2的S0/2；
 
配置命令：
1、将R2变为帧中继交换机
en
conf t
hostname fr-sw
frame-relay swithing
interface s0/0
no ip address
clock rate 128000
encapsulation frame-relay
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 103 interface s0/1 301
frame-relay route 104 interface s0/2 401
no shutdown
interface s0/1
no ip address
clock rate 128000
encapsulation frame-relay
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 301 interface s0/1 103
no shutdown
interface s0/0
no ip address
clock rate 128000
encapsulation frame-relay
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 104 interface s0/0 401  
no shutdown
end
sh frame-relay route
 
R1:
en
conf t
hostname r1
interface loopback 1
ip address 1.1.1.1 255.255.255.0
no shutdown
exit
interface s0/0
no shutdown
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
ip ospf network point-to-point
exit
interface s0/0.1 point-to-point
ip address 192.168.1.1 255.255.255.0
frame-relay interface-dlci 103
interface s0/0.2point-to-point
ip address 192.168.21 255.255.255.0
frame-relay interface-dlci 104
exit
router ospf 1
router-id 1.1.1.1
network 1.1.1.0 0.0.0.255 area 0
network 192.168.1.0 0.0.0.255 area 0
network 192.168.2.0 0.0.0.255 area 0
exit
 
R3
en
conf t
hostname r3
interface loopback 1
ip address 3.3.3.3 255.255.255.0
no shutdown
exit
interface s0/0
no shutdown
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
ip ospf network point-to-point
exit
interface s0/0.1 point-to-point
ip address 192.168.1.2 255.255.255.0
frame-relay interface-dlci 301
exit
router ospf 1
router-id 3.3.3.3
network 3.3.3.0 0.0.0.255 area 0
network 192.168.1.0 0.0.0.255 area 0
network 192.168.2.0 0.0.0.255 area 0
exit
 
R4
en
conf t
hostname r4
interface loopback 1
ip address 4.4.4.4 255.255.255.0
no shutdown
exit
interface s0/0
no shutdown
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
ip ospf network point-to-point
exit
interface s0/0.1 point-to-point
ip address 192.168.2.2 255.255.255.0
frame-relay interface-dlci 401
exit
router ospf 1
router-id 4.4.4.4
network 4.4.4.0 0.0.0.255 area 0
network 192.168.1.0 0.0.0.255 area 0
network 192.168.2.0 0.0.0.255 area 0
exit