A method for realizing route discovery in a network includes: classifying a level of a node in the network; receiving a route request packet from a node adjacent to the node; comparing a node level indicated by node level information contained in the received route request packet with the level of the node; updating, in a case where the level of the node is higher than the node level indicated by the node level information contained in the route request packet, the node level indicated by the node level information contained in the route request packet to be the level of the node; and forwarding the updated route request packet to other nodes adjacent to the node.