帧中继问题

光影菜鸟

请教一个帧中继问题，用路由器模拟帧中继交换机：如图：如何能让r1-r4,r3-r4做PVC 2.3之间不做。如何能互相ping通。






我的配置如下：

FR:
interface Serial0/0
no ip address
encapsulation frame-relay
serial restart-delay 0
clock rate 64000
no frame-relay inverse-arp
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 204 interface Serial0/1 402
!         
interface Serial0/1
no ip address
encapsulation frame-relay
serial restart-delay 0
clock rate 64000
no frame-relay inverse-arp
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 402 interface Serial0/0 204
frame-relay route 403 interface Serial0/2 304
!         
interface Serial0/2
no ip address
encapsulation frame-relay
serial restart-delay 0
clock rate 64000
no frame-relay inverse-arp
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 304 interface Serial0/1 403


r2:
interface Serial0/0
ip address 1.1.234.2 255.255.255.248
encapsulation frame-relay
serial restart-delay 0
frame-relay map ip 1.1.234.4 204 broadcast
no frame-relay inverse-arp

r3:
interface Serial0/0
ip address 1.1.234.3 255.255.255.248
encapsulation frame-relay
serial restart-delay 0
frame-relay map ip 1.1.234.4 304 broadcast
no frame-relay inverse-arp

r4:
interface Serial0/0
ip address 1.1.234.4 255.255.255.248
encapsulation frame-relay
serial restart-delay 0
frame-relay map ip 1.1.234.2 402 broadcast
frame-relay map ip 1.1.234.3 403 broadcast
no frame-relay inverse-arp