Apparatus and method for communicating

PURPOSE: A communication apparatus and method thereof are provided to transmit a downstream packet to a portable terminal through a downstream agent by selecting the downstream agent from adjacent sensor nodes. CONSTITUTION: A portable terminal transmits query to an upstream agent(S810). The upstream agent cap encapsulates the query(S820). A gateway transmits the upstream packet to a server(S830). The gateway receives the response of the server(S840). The gateway transmits the response to a downstream agent(S850). The downstream agent transmits the response to the portable terminal(S860).