A method for flooding a route request packet that is received at a node in a communication system constructed of at least three nodes including a source node that requests to establish a route and a destination node that receives the route request. One of a plurality of levels having different transmission periods is determined using a strength of a received signal of a measured packet. A transmission start point is selected at the determined level, and it is determined whether a route request packet is re-received before the selected transmission start point. The received packet is broadcast at the selected transmission start point when the packet is not re-received. The transmission start point is randomly selected within the transmission period or at the level in consideration of the number of the connected nodes.