Network slice selection method, device, and system

1. A network slice selection method, comprising:

obtaining, by a first network device, user characteristic information of a user of a first terminal, wherein the user characteristic information includes one or more pieces of single network slice selection assistance information (S-NSSAI) corresponding to the user, comprising:

sending, by the first network device, a first message to the first terminal, wherein the first message is useable to request a user identifier of the user of the first terminal;

receiving, by the first network device, the user identifier from the first terminal; and

obtaining, by the first network device, the user characteristic information of the user of the first terminal based on the user identifier;

sending, by the first network device, a second message to a database network element or an authentication server, wherein the second message carries the user identifier and is useable to request the user characteristic information of the user of the first terminal; and

receiving, by the first network device, the user characteristic information from the database network element or the authentication server; and

determining, by the first network device based on the user characteristic information, allowed NSSAI corresponding to the first terminal, wherein the allowed NSSAI includes the one or more pieces of S-NSSAI; or

in response to the first network device not supporting serving a network slice indicated in the one or more pieces of S-NSSAI, determining, by the first network device based on the one or more pieces of S-NSSAI, a second network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI.

2. The method according to claim 1 , further comprising:

in response to the determining, by the first network device, the allowed NSSAI corresponding to the first terminal, sending, by the first network device, the allowed NSSAI to the first terminal, wherein the allowed NSSAI is configured indicate one or more network slices that the first terminal is allowed to access.

3. The method according to claim 1 , further comprising:

before the obtaining, by the first network device, the user characteristic information of the user of the first terminal, receiving, by the first network device, a third message from the first terminal, wherein the third message includes first indication information useable to indicate that the first terminal has the user characteristic information.

4. The method according to claim 3 , wherein:

the third message includes requested NSSAI of the first terminal, and the first indication information is tag information in S-NSSAI included in the requested NSSAI of the first terminal.

5. The method according to claim 1 , further comprising:

before the obtaining, by the first network device, the user characteristic information of the user of the first terminal, obtaining, by the first network device, subscription data of the first terminal from the database network element, wherein the subscription data includes second indication information useable to indicate that the first terminal has the user characteristic information.

6. The method according to claim 5 , wherein:

the subscription data includes subscribed NSSAI of the first terminal, and the second indication information is tag information in S-NSSAI included in the subscribed NSSAI of the first terminal.

7. The method according to claim 1 , wherein:

the determining, by the first network device based on the one or more pieces of S-NSSAI, the second network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI comprises:

sending, by the first network device, a fourth message to a slice selection function network element, wherein the fourth message carries the one or more pieces of S-NSSAI, and is configured to be useable to request another network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI; and

receiving, by the first network device, information about the second network device from the slice selection function network element.

8. The method according to claim 7 , wherein:

the determining, by the first network device based on the one or more pieces of S-NSSAI, the second network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI comprises:

sending, by the first network device, a fifth message to a slice selection function network element, wherein the fifth message carries the one or more pieces of S-NSSAI, and is useable to request the other network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI;

receiving, by the first network device, information about a candidate network device set from the slice selection function network element; and

selecting, by the first network device, the second network device from the candidate network device set based on the information about the candidate network device set.

9. A first network device, comprises:

a processor; and

a transceiver, wherein:

the processor is configured to obtain user characteristic information of a user of a first terminal, wherein the user characteristic information includes one or more pieces of single network slice selection assistance information (S-NSSAI) corresponding to the user;

the processor is configured to send a first message to the first terminal, wherein the first message is useable to request a user identifier of the user of the first terminal;

the processor is configured to receive the user identifier from the first terminal;

the processor is configured to obtain the user characteristic information of the user of the first terminal based on the user identifier;

the processor is configured to send a second message to a database network element or an authentication server, wherein the second message carries the user identifier and is useable to request the user characteristic information of the user of the first terminal;

the processor is configured to receive the user characteristic information from the database network element or the authentication server; and

the processor is configured to determine, based on the user characteristic information, allowed NSSAI corresponding to the first terminal, wherein the allowed NSSAI includes the one or more pieces of S-NSSAI; or

the processor is configured to in response to the first network device not supporting serving a network slice indicated in the one or more pieces of S-NSSAI, determine, based on the one or more pieces of S-NSSAI, a second network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI.

10. The first network device according to claim 9 , wherein

the transceiver is configured to: after the processor determines the allowed NSSAI corresponding to the first terminal, send the allowed NSSAI to the first terminal, wherein the allowed NSSAI indicates one or more network slices that the first terminal is allowed to access.

11. The first network device according to claim 9 , wherein:

before the processor obtains the user characteristic information of the user of the first terminal, the transceiver is configured to receive a third message from the first terminal, wherein the third message includes first indication information to indicate that the first terminal has the user characteristic information.

12. The first network device according to claim 11 , wherein:

the third message includes requested NSSAI of the first terminal, and the first indication information is tag information in S-NSSAI included in the requested NSSAI of the first terminal.

13. The first network device according to claim 9 , wherein:

before the processor obtains the user characteristic information of the user of the first terminal, the transceiver is configured to obtain subscription data of the first terminal from the database network element, wherein the subscription data includes second indication information, and the second indication information indicates that the first terminal has the user characteristic information.

14. The first network device according to claim 13 , wherein:

the subscription data includes subscribed NSSAI of the first terminal, and the second indication information is tag information in S-NSSAI included in the subscribed NSSAI of the first terminal.

15. The first network device according to claim 9 , wherein:

the determining, based on the one or more pieces of S-NSSAI, a second network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI comprises:

send a fourth message to a slice selection function network element, wherein the fourth message carries the one or more pieces of S-NSSAI, and is useable to request another network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI; and

receive information about the second network device from the slice selection function network element.

16. The first network device according to claim 15 , wherein:

the determining, based on the one or more pieces of S-NSSAI, the second network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI comprises:

send a fifth message to the slice selection function network element, wherein the fifth message carries the one or more pieces of S-NSSAI, and is useable to request the other network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI;

receive information about a candidate network device set from the slice selection function network element; and

select the second network device from the candidate network device set based on the information about the candidate network device set.

17. A network slice selection apparatus, comprising:

a processor; and

a memory having instructions stored thereon that, in response to being executed by the processor, cause the processor to:

obtain user characteristic information of a user of a first terminal, wherein the user characteristic information includes one or more pieces of single network slice selection assistance information includes (S-NSSAI) corresponding to the user, comprising:

send a first message to the first terminal, wherein the first message is useable to request a user identifier of the user of the first terminal;

receive the user identifier from the first terminal; and

obtain the user characteristic information of the user of the first terminal based on the user identifier;

send a second message to a database network element or an authentication server, wherein the second message carries the user identifier and is useable to request the user characteristic information of the user of the first terminal; and

receive the user characteristic information from the database network element or the authentication server; and

determine, based on the user characteristic information, allowed NSSAI corresponding to the first terminal, wherein the allowed NSSAI includes the one or more pieces of S-NSSAI; or

in response to a first network device not supporting serving a network slice indicated in the one or more pieces of S-NSSAI, determine, based on the one or more pieces of S-NSSAI, a second network device that supports serving the network slice indicated in the one or more pieces of S-NSSAI.

18. The apparatus according to claim 17 , wherein the instructions, in response to being executed by the processor, further cause the processor to:

in response to the determining, by the first network device, the allowed NSSAI corresponding to the first terminal, send the allowed NSSAI to the first terminal, wherein the allowed NSSAI is configured to be useable to indicate one or more network slices that the first terminal is allowed to access.

19. The apparatus according to claim 17 , wherein the instructions, in response to being executed by the processor, further cause the processor to:

before the obtaining the user characteristic information of the user of the first terminal, receive a third message from the first terminal, wherein the third message includes first indication information indicates that the first terminal has the user characteristic information.

20. The apparatus according to claim 19 , wherein:

the third message includes requested NSSAI of the first terminal, and the first indication information is tag information in S-NSSAI included in the requested NSSAI of the first terminal.