Abstract: The present disclosure provides a method for Network Application Function to acquire subscriber identity information. According to application of the disclosed method, NAF acquires subscriber identity information so as to facilitate its subscriber management, such as to achieve subscriber charging and/or access control. When NAF serves as an application server proxy, it is able to insert subscriber identity information into the message it forwards, which facilitates the application server that receives the forwarded message to identify the subscriber identity. It is easy and convenient to implement the disclosed method, and the present disclosure is also compatible with the existing associated flows.

Abstract: The invention disclose a method for verifying the validity of a user, making full use of a B-TID as the bridge for establishing confidence between a NAF and a user equipment, and the BSF assigning a term of validity for the B-TID, thereby extending the function of the B-TID, enabling the NAF to verify the term of validity for using the B-TID, and accordingly, achieving a further verification of the validity to the user. By using the method of the invention, it is possible to avoid the situation in which one B-TID is permanently valid for one or more NAFs, enhance the system security, decrease the risks caused by the theft of users' B-TID and corresponding secret keys, and at the same time, implement B-TID management by the NAF. In addition, a combination of the method with billing system makes it easy to implement the function of charging a user.

Abstract: Disclosed herein is a method for Wireless Local Area Network (WLAN) User Equipment (UE) selection of a Packet Data Gateway (PDG). When the WLAN UE fails to access, the PDG returns a message containing the failure cause value to the WLAN UE that has sent the request such that the WLAN UE could perform different operations according to the specific failure cause value in the message to select a PDG. For example, the WLAN UE may request DNS again to obtain the IP address of the PDG in a home network by parsing in connection with a requested service, or the WLAN UE may first subscribe to the service before re-performing the operation of selecting a PDG, or the WLAN UE may re-select a PDG with another parsed IP address and send a connection request thereto. As a result, the process of WLAN UE asking DNS to re-direct to the home network to select PDG is left out when possible, unnecessary signaling is avoided, and the network resources are saved.