Patent ID: 8326263

Claim:
A method for selecting a policy and charging rules function, comprising: when a User Equipment (UE) accesses a 3GPP system through an Evolved-Universal Terrestrial Radio Access Network (E-UTRAN) of a visited network or a trusted non-3GPP IP access network or untrusted non-3GPP IP access network, upon receiving a session establishment request message sent by a Policy and Charging Control (PCC) client located in the visited network, a Diameter Routing Agent (DRA) of the visited network searching records stored locally, and if records of an Internet Protocol-Connectivity Access Network (IP-CAN) session corresponding to the session establishment request message are not found, the DRA of the visited network selecting a Policy and Charging Rules Function (PCRF) of the visited network for the IP-CAN session and records a corresponding relationship between the IP-CAN session and the PCRF of the visited network; and forwarding the session establishment request message to the selected PCFR of the visited network or instructing the PCC client to transmit the session establishment request message to the selected PCRF of the visited network; if the records of the IP-CAN session are found, the DRA of the visited network forwarding the message to the PCRF of the visited network corresponding to the records, or instructing the PCC client to transmit the message to the PCRF of the visited network corresponding to the records; and the PCRF of the visited network forwarding the session establishment request message to a DRA of a home network, upon receiving the session establishment request message sent by the PCRF of the visited network, the DRA of the home network searching records stored locally, and if the records of the IP-CAN session are not found, the DRA of the home network selecting the PCRF of the home network for the IP-CAN session and recording the corresponding relationship between the IP-CAN session and the PCRF of the home network, and forwarding the session establishment request message to the selected PCRF of the home network or instructing the PCRF of the visited network to transmit the session establishment request message to the selected PCRF of the home network, if the records of the IP-CAN session are found, the DRA of the home network forwards the message to the PCRF of the home network corresponding to the records, or instructs the PCRF of the visited network to transmit the message to the PCRF of the home network corresponding to the records; or when searching records stored locally and finding that the PCRF of the home network has already been selected for the IP-CAN session, the PCRF of the visited network forwarding the session establishment request message to the selected PCRF of the home network.