PCF determining method, apparatus, and system

A method implemented by a first visited access and mobility management function apparatus serving a terminal, wherein the method comprises:

• receiving, from a second visited access and mobility management function apparatus that previously served the terminal, a policy control function identifier identifying a policy control function apparatus that stored a context of the terminal and that was previously used by the second visited access and mobility management function apparatus, the first visited access and mobility management function apparatus and the second visited access and mobility management function apparatus belonging to a same visited public land mobile network (VPLMN), and the policy control function apparatus comprising a home policy control function apparatus in a home public land mobile network (HPLMN) and a visited policy control function apparatus in the VPLMN;
• selecting a target policy control function apparatus according to policy control function information from a network function repository function apparatus or policy control function information stored in the first visited access and mobility management function apparatus;
• sending to the second visited access and mobility management function apparatus a message which indicates that the terminal is registered with the first visited access and mobility management function apparatus successfully and which includes first indication information indicating that the first visited access and mobility management function apparatus has determined to select the target policy control function apparatus other than the policy control function apparatus identified by the policy control function identifier, and wherein the first indication information in the message is for initiating a procedure to delete the context of the terminal stored in the policy control function apparatus identified by the policy control function identifier;
• and
• obtaining policy information from the target policy control function apparatus.

A second visited access and mobility management function apparatus that previously served a terminal, wherein the second visited access and mobility management function apparatus comprises:

• one or more processors coupled to a memory storing instructions, wherein when the instructions are executed by the one or more processors, the second access and mobility management function apparatus is caused to:
• send, to a first visited access and mobility management function apparatus serving the terminal, a policy control function identifier identifying a policy control function apparatus that has stored a context of the terminal and that was previously used by the second visited access and mobility management function apparatus, the first visited access and mobility management function apparatus and the second visited access and mobility management function apparatus belong to a same visited public land mobile network (VPLMN), and the policy control function apparatus including a home policy control function apparatus in a home public land mobile network (HPLMN) and a visited policy control function apparatus in the VPLMN;
• receive from the first visited access and mobility management function apparatus, a message which indicates that the terminal is registered with the first visited access and mobility management function apparatus successfully and which includes first indication information indicating that the first access and mobility function apparatus has determined to select a target policy control function apparatus other than the policy control function apparatus identified by the policy control function identifier;
• and
• initiate, based on the first indication information in the message, a procedure to delete the context of the terminal stored in the policy control function apparatus identified by the policy control function identifier.

A first visited access and mobility management function apparatus serving a terminal, wherein the first visited access and mobility management function apparatus comprises:

• one or more processors coupled to a memory storing instructions, wherein when the instructions are executed by the one or more processors, the first visited access and mobility management function apparatus is caused to:
• receive, from a second visited access and mobility management function apparatus previously served the terminal, a policy control function identifier identifying a policy control function apparatus that has stored a context of the terminal and that was previously used by the second visited access and mobility management function apparatus, the first visited access and mobility management function apparatus and the second visited access and mobility management function apparatus belonging to a same visited public land mobile network (VPLMN), and the policy control function apparatus comprising a home policy control function apparatus in a home public land mobile network (HPLMN) and a visited policy control function apparatus in the VPLMN;
• select a target policy control function apparatus according to policy control function information from a network function repository function apparatus or policy control function information stored in the first visited access and mobility management function apparatus;
• send, to the second visited access and mobility management function apparatus, a message that indicates that the terminal is registered with the first visited access and mobility management function apparatus successfully and that includes first indication information indicating that the first visited access and mobility management function apparatus had determined to select the target policy control function apparatus other than the policy control function apparatus identified by the policy control function identifier, and the first indication information in the message being for initiating a procedure to delete the context of the terminal stored in the policy control function apparatus identified by the policy control function identifier;
• and
• obtain, from the target policy control function apparatus, policy information.