Internet technology assumes all links are bidirectional, hence it does not take advantage of the broadcast nature of Radio Frequency communications. RFC3077 emulates broadcast connectivity in UDL(Uni Direstional Link) and it provides generic solution for all network layer mechanisms. However, this method doesn't support some OSPF network topology. We extended the definition of UDL. Our extention enables a node does not have to be reachable from another node. With our extention, we can use every connectivities over UDL as routes Then we extended OSPF to handle unidirectional links. Our extension enables all OSPF routers to construct the routing table including UDL, and it is compatible with general OSPF implementation.