message to the node b alone if not maintaining the routing table on the destination node i the node a unicasts the rreq message to the node d since the node a knows that the destination node is not its descendent node the detailed description of the rreq message transmitted from the node a is omitted for conciseness the node d unicasts the updated rreq message to the destination node i at step s 316 the destination node i creates a rrep message in reply to the rreq message and unicasts the created rreq message to the node d at step s 318 the node d transmits the updated rrep message to the node c using the information stored in the routing table as receiving the rreq message at step s 320 and the node c transmits the updated rrep message to the node b in the same manner at step s 322 as a result the route is established for transmitting data from the node b to the destination node i the node b transmits the stored data to the destination node i following the established route fig4 illustrates exemplary steps of the rreq received node according to one embodiment of the present invention a node.