In a portable Internet system, packets are classified into a first packet classified as a transport connection identifier (CID) and a second packet that is not classified as a transport CID by using an established packet classification rule. An application program of the second packet is searched from a plurality of application programs by using the header information of the second packet in the portable Internet system. QoS parameter information for the searched application program is obtained from a plurality of QoS parameter informations corresponding to the plurality of application programs.