Router(config-if)#no ip address
Router(config-if)#encapsulation frame-relay
Router(config)#interface Serial0.1 point-to-point
Router(config-subif)#ip address 10.1.1.1 255.255.255.0
Router(config-subif)#frame-relay interface-dlci 51
Router(config)#interface Serial0.2 point-to-point
Router(config-subif)#ip address 10.1.2.1 255.255.255.0
Router(config-subif)#frame-relay interface-dlci 52
Router(config-router)#network 10.1.0.0 0.0.255.255