A method for forwarding a data message in a process of initiating communication, which is applied to an identification identifier and location separation network, the method comprising: an Access Service Node, ASN, where a terminal is located receiving the data message containing an access identifier, AID, of a correspondent node which is transmitted by the terminal, inquiring AID-RID mapping information in a local cache according to the AID of the correspondent node, if a Routing-Location Identifier, RID, corresponding to the AID of the correspondent node is not found, then the ASN where the terminal is located treating a RID to which an AID of the terminal corresponds as a source address and treating a routing identifier RIDi of an Identity Location Register, ILR, in a mapping forwarding plane connected to the ASN where the terminal is located as a destination address, wherein both addresses are encapsulated in a newly added message header, the ASN where the terminal is located forwarding the data message to the mapping forwarding plane and initiating a location inquiring process of the correspondent node to the mapping forwarding plane and meanwhile transmitting the data message to the mapping forwarding plane; after receiving the data message, the mapping forwarding plane inquiring the RID corresponding to the AID of the correspondent node, encapsulating the RID corresponding to the AID of the correspondent node in the message header of the data message, replacing the RIDi in the newly added message header with the RID corresponding to the AID of the correspondent node and then forwarding (304a-306) the data message to an ASN where the correspondent node is located through a generalized forwarding plane; and after receiving the data message, the ASN where the correspondent node is located stripping the RID from the data message and then transmitting the data message to the correspondent node; wherein when a location of the terminal is changed, a procedure of registering and updating mapping information is initiated to the mapping forwarding plane through the ASN where the terminal is located; after allocating a new RID to the terminal, the ASN where the terminal is located initiates an update message carrying the AID of the terminal and the new RID of the terminal to the ILR; after receiving the update message, the ILR updates an AID-RID entry to which the terminal corresponds; wherein a backbone network is divided into the mapping forwarding plane and the generalized forwarding plane. an Access Service Node, ASN, where a terminal is located receiving the data message containing an access identifier, AID, of a correspondent node which is transmitted by the terminal, inquiring AID-RID mapping information in a local cache according to the AID of the correspondent node, if a Routing-Location Identifier, RID, corresponding to the AID of the correspondent node is not found, then the ASN where the terminal is located treating a RID to which an AID of the terminal corresponds as a source address and treating a routing identifier RIDi of an Identity Location Register, ILR, in a mapping forwarding plane connected to the ASN where the terminal is located as a destination address, wherein both addresses are encapsulated in a newly added message header, the ASN where the terminal is located forwarding the data message to the mapping forwarding plane and initiating a location inquiring process of the correspondent node to the mapping forwarding plane and meanwhile transmitting the data message to the mapping forwarding plane; after receiving the data message, the mapping forwarding plane inquiring the RID corresponding to the AID of the correspondent node, encapsulating the RID corresponding to the AID of the correspondent node in the message header of the data message, replacing the RIDi in the newly added message header with the RID corresponding to the AID of the correspondent node and then forwarding (304a-306) the data message to an ASN where the correspondent node is located through a generalized forwarding plane; and after receiving the data message, the ASN where the correspondent node is located stripping the RID from the data message and then transmitting the data message to the correspondent node; wherein when a location of the terminal is changed, a procedure of registering and updating mapping information is initiated to the mapping forwarding plane through the ASN where the terminal is located; after allocating a new RID to the terminal, the ASN where the terminal is located initiates an update message carrying the AID of the terminal and the new RID of the terminal to the ILR; after receiving the update message, the ILR updates an AID-RID entry to which the terminal corresponds; wherein a backbone network is divided into the mapping forwarding plane and the generalized forwarding plane.