Network access control method, SDF, CP, UP, and network system

A network device applied to a first user plane (UP) of a plurality of UPs in a network system, the network device comprising:

• at least one processor;
• one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor, the programming instructions including instructions to:
• report a carrier-grade network address translation (CGN) resource to a steering decision function (SDF), wherein the CGN resource comprises a CGN service load status of the first UP, wherein the CGN service load status reflects a capability of the first UP for a CGN service, wherein the network system comprises the SDF, the plurality of UPs, and a control plane (CP), and wherein the first UP is one of the plurality of UPs;
• receive a first CGN steering policy sent by the CP, wherein the first CGN steering policy comprises a first CGN instance, and wherein the first CGN instance indicates the first UP having an available CGN resource;
• and
• bear traffic of a user equipment.

A network system, comprising:

• a steering decision function (SDF);
• a plurality of user planes (UPs);
• and
• a control plane (CP);
• wherein the plurality of UPs are configured to report CGN resources to the SDF, wherein the SDF obtains a CGN resource pool according to the reported CGN resources, wherein the CGN resources comprise a CGN service load status of each UP of the plurality of UPs, and the CGN service load status reflects a capability of each of the plurality of UPs for a CGN service;
• wherein the CP is configured to send a CGN instance obtaining request to the SDF, wherein the CGN instance obtaining request indicates to allocate a CGN instance to user equipment;
• wherein the SDF is configured to allocate a first CGN instance to the user equipment based on the CGN resource pool, wherein the first CGN instance indicates a first UP having an available CGN resource, and wherein the first UP is one of the plurality of UPs, and wherein the SDF is further configured to send the first CGN instance to the CP;
• wherein the CP is further configured to generate a first CGN steering policy based on the first CGN instance, wherein the first CGN steering policy indicates to steer traffic of the user equipment to the first UP indicated by the first CGN instance, and wherein the CP is further configured to send the first CGN steering policy to the first UP;
• and
• wherein the first UP is configured to bear the traffic of the user equipment.