The device can be the second access network device and the first mapping relationship can be preconfigured in the at least one access network device, and the at least one access network device comprises the second access network device. In another embodiment, the device is a network node dedicated for parsing the access stratum context identifier information to obtain an identifier of an access network device, and the first mapping relationship is preconfigured in the network node. Moreover, the determining unit can be specifically configured to query for the first mapping relationship and obtain the identifier of the first access network device according to the access stratum context identifier information of the first terminal device that is obtained from the second access network device.

In an embodiment, the access stratum context identifier information of the first terminal device is pre-allocated by the first access network device to the first terminal device. The obtaining unit can be specifically configured to, when the first terminal device is in a radio resource control RRC inactive state and there is data needing to be transmitted, obtain the access stratum context identifier information of the first terminal device.