A communication method for a mobile communication system having a node for sending data to a gateway via neighboring nodes and gateways for sending the data from the nodes to an Internet network, and for setting a path for data transmissions between a gateway and a node, including: transmitting via the gateway a message including path information and a prefix; and setting a path for sending data to the node that sent the message, when a node that received the message, directly or via another node, has the data to be sent to the gateway; and sending the data via the set path.