Business classification service method and system as well as GGSN and terminal

The invention discloses a business classification service method. The business classification service method comprises the following steps: when a TCP message sent by a terminal is received, analyzing a reserved field in the TCP message so as to obtain the identifying information of the terminal; carrying out classification service on businesses transmitted by the terminal according to the identifying information, wherein the reserved field in the TCP message is identified by the terminal. The invention further discloses a business classification service system, a GGSN and the terminal. Through the adoption of the technical scheme, classification service can be carried out on the businesses of the specific terminal, so that the utilizing rate of wireless network resources is improved, and the quality of business differentiated service is improved.