Method for carrying message service type to AN based on GRE expansion, apparatus thereof and system thereof

The invention relates to a method for carrying a message service type to an AN (access network) based on GRE (generic routing encapsulation) expansion, an apparatus thereof and a system thereof. The method comprises the following steps: acquiring a service type of an IP message, and carrying the service type at an expansion attribute field of a GRE message, wherein, the GRE message is packaged with the IP message; bearing the GRE message at an RP (radio packet) link and sending the GRE message to the AN. By utilizing a GRE expansion attribute domain in a GRE protocol borne by the RP link between a PDSN (packet data service node) and the AN, through customizing a new GRE expansion attribute, service type information of the message is carried to the AN, flexibility and scalability of the AN are enhanced, and system control surface signaling cost is reduced simultaneously.