Session management method, device, and system

1. A session management method comprising:

receiving, by an intermediate session management network element from a remote anchor session management network element, one or more local data network access identifiers (DNAIs);

determining, by the intermediate session management network element, a target DNAI based on current location information of a terminal and the one or more local DNAIs;

selecting, by the intermediate session management network element, a local user plane function network element for the terminal based on the target DNAI; and

sending, by the intermediate session management network element and to the remote anchor session management network element, the target DNAI for determining a first policy and charging control (PCC) rule for the local user plane function network element.

2. The session management method of claim 1 , wherein the one or more local DNAIs correspond to a session of the terminal, wherein the one or more local DNAIs are supported by the intermediate session management network element, and wherein the one or more local DNAIs are from a second PCC rule.

3. The session management method of claim 1 , further comprising:

obtaining, by the intermediate session management network element from the remote anchor session management network element, information about a session access mode;

determining, by the intermediate session management network element based on the information, that the session access mode is a multi-homing mode; and

sending, by the intermediate session management network element to the remote anchor session management network element, local Internet Protocol (IP) address information of the terminal.

4. The session management method of claim 1 , further comprising:

obtaining, by the intermediate session management network element, application identification information corresponding to the target DNAI; and

generating, by the intermediate session management network element based on the application identification information, a target rule instructing the local user plane function network element to forward a received data packet.

5. The session management method of claim 1 , further comprising instructing the local user plane function network element to offload a data packet to a local data network corresponding to the target DNAI, wherein the data packet comprises a source address that is a local Internet Protocol (IP) address.

6. The session management method of claim 1 , further comprising:

obtaining, by the intermediate session management network element, remote Internet Protocol (IP) address information; and

generating, by the intermediate session management network element based on the remote IP address information, a target rule instructing the local user plane function network element to forward a received data packet.

7. The session management method of claim 1 , further comprising instructing, by the intermediate session management network element, the local user plane function network element to offload a data packet to a remote anchor user plane function network element, wherein the data packet comprises a source address that is a remote Internet Protocol (IP) address.

8. The session management method of claim 7 , wherein instructing, by the intermediate session management network element, the local user plane function network element comprises sending, to the local user plane function network element, a remote routing rule to offload the data packet to the remote anchor user plane function network element.

9. An intermediate session management network element comprising:

a memory configured to store instructions; and

a processor coupled to the memory and configured to execute the instructions to cause the intermediate session management network element to:

receive, from a remote anchor session management network element, one or more local data network access identifiers (DNAIs);

determine a target DNAI based on current location information of a terminal and the one or more local DNAIs;

select a local user plane function network element for the terminal based on the target DNAI; and

send, to the remote anchor session management network element, the target DNAI for determining a first policy and charging control (PCC) rule for the local user plane function network element.

10. The intermediate session management network element of claim 9 , wherein the one or more local DNAIs correspond to a session of the terminal, wherein the one or more local DNAIs are supported by the intermediate session management network element, and wherein the one or more local DNAIs are from a second rule.

11. The intermediate session management network element of claim 9 , wherein the processor is further configured to execute the instructions to cause the intermediate session management network element to:

obtain, from the remote anchor session management network element, information about a session access mode;

determine, based on the information, that the session access mode is a multi-homing mode; and

send, to the remote anchor session management network element, local Internet Protocol (IP) address information of the terminal.

12. The intermediate session management network element of claim 9 , wherein the processor is further configured to execute the instructions to cause the intermediate session management network element to:

obtain application identification information corresponding to the target DNAI; and

generate, based on the application identification information, a target rule instructing the local user plane function network element to forward a received data packet.

13. The intermediate session management network element of claim 9 , wherein the processor is further configured to execute the instructions to cause the intermediate session management network element to instruct the local user plane function network element to offload a data packet to a local data network corresponding to the target DNAI, and wherein the data packet comprises a source address that is a local Internet Protocol (IP) address.

14. The intermediate session management network element of claim 9 , wherein the processor is further configured to execute the instructions to cause the intermediate session management network element to:

obtain remote Internet Protocol (IP) address information; and

generate, based on the remote IP address information, a target rule instructing the local user plane function network element to forward a received data packet.

15. The intermediate session management network element of claim 9 , wherein the processor is further configured to execute the instructions to cause the intermediate session management network element to instruct the local user plane function network element to offload a data packet to a remote anchor user plane function network element, and wherein the data packet comprises a source address that is a remote Internet Protocol (IP) address.

16. The intermediate session management network element of claim 15 , wherein the processor is further configured to execute the instructions to cause the intermediate session management network element to instruct the local user plane function network element by sending, to the local user plane function network element, a remote routing rule to offload the data packet to the remote anchor user plane function network element.

17. A computer program product comprising instructions that are stored on a non-transitory computer-readable medium and that, when executed by a processor, cause an intermediate session management network element to:

receive, from a remote anchor session management network element, one or more local data network access identifiers (DNAIs);

determine a target DNAI based on current location information of a terminal and the one or more local DNAIs;

select a local user plane function network element for the terminal based on the target DNAI; and

send, to the remote anchor session management network element, the target DNAI for determining a first policy and charging control (PCC) rule for the local user plane function network element.

18. The computer program product of claim 17 , wherein the one or more local DNAIs correspond to a session of the terminal, wherein the one or more local DNAIs are supported by the intermediate session management network element, and wherein the one or more local DNAIs are from a second rule.

19. The computer program product of to claim 17 , wherein the instructions, when executed by the processor, further cause the intermediate session management network element to:

obtain, from the remote anchor session management network element, information about a session access mode;

determine, based on the information about the session access mode, that the session access mode is a multi-homing mode; and

send, to the remote anchor session management network element, local Internet Protocol (IP) address information of the terminal.

20. The computer program product of claim 17 , wherein the instructions, when executed by the processor, further cause the intermediate session management network element to:

obtain remote Internet Protocol (IP) address information; and

generate, based on the remote IP address information, a target rule instructing the local user plane function network element to forward a received data packet.

21. The computer program product of claim 17 , wherein the instructions, when executed by the processor, further cause the intermediate session management network element to instruct the local user plane function network element to offload a data packet to a remote anchor user plane function network element, and wherein the data packet comprises a source address that is a remote Internet Protocol (IP) address.

22. The computer program product of claim 21 , wherein the instructions, when executed by the processor, further cause the intermediate session management network element to instruct the local user plane function network element by sending, to the local user plane function network element, a remote routing rule to offload the data packet to the remote anchor user plane function network element.