Method, device and system for identifying application identifier

1. A method for identifying an application identifier (APP ID), the method comprising:

receiving, by a packet flow description function network element, a query request, wherein the query request comprises a signature parameter of a first service data flow, and the signature parameter is used to describe the first service data flow;

determining, by the packet flow description function network element, a correspondence between a first APP ID and a first packet flow description (PFD) that matches the signature parameter, as an APP ID corresponding to the first service data flow; and

responsive to determining the correspondence between the first APP ID and the first PFD, sending, by the packet flow description function network element, a query response, wherein the query response comprises the first APP ID,

wherein determining the correspondence between the first APP ID and the first PFD that matches the signature parameter, as the APP ID corresponding to the first service data flow comprises:

matching, by the packet flow description function network element, the signature parameter with at least one PFD, to determine that the first PFD matches the signature parameter; and

determining, by the packet flow description function network element based on the first PFD and the correspondence between the first PFD and first APP ID, the first APP ID as the APP ID corresponding to the first service data flow.

2. The method of claim 1 , wherein before matching, by the packet flow description function network element, the signature parameter with the at least one PFD, the method further comprises:

determining, by the packet flow description function network element, that a correspondence between the signature parameter and an APP ID does not exist.

3. The method of claim 1 , further comprising:

storing, by the packet flow description function network element, a correspondence between the signature parameter and the first APP ID.

4. The method of claim 1 , wherein receiving, by the packet flow description function network element, the query request comprises:

receiving, by the packet flow description function network element, the query request from a user plane network element through a communications interface between the packet flow description function network element and the user plane network element; and

wherein sending, by the packet flow description function network element, the query response comprises:

sending, by the packet flow description function network element, the query response to the user plane network element through the communications interface.

5. The method of claim 1 , wherein receiving, by the packet flow description function network element, the query request comprises:

receiving, by the packet flow description function network element, the query request from a session management network element through a service-based interface between the packet flow description function network element and the session management network element; and

wherein sending, by the packet flow description function network element, the query response comprises:

sending, by the packet flow description function network element, the query response to the session management network element through the service-based interface.

6. The method of claim 5 , wherein:

the query response further comprises a forwarding indication, and the forwarding indication is used to indicate the session management network element to send the first APP ID to a user plane network element.

7. The method of claim 1 , wherein:

the packet flow description function network element is deployed in a network exposure function network element.

8. The method of claim 1 , further comprising:

receiving, by the packet flow description function network element from an application function network element, the first PFD and first APP ID corresponding to the first PFD, and storing the correspondence between the first PFD and the first APP ID.

9. The method of claim 1 , wherein:

the signature parameter comprises one or more of: a 5-tuple of the first service data flow, a uniform resource locator (URL) of the first service data flow, or a domain name of the first service data flow.

10. A system for identifying an application identifier (APP ID), the system comprising:

a first network element and a packet flow description function network element, wherein:

the first network element is configured to send a query request to the packet flow description function network element, wherein the query request comprises a signature parameter of a first service data flow, and the signature parameter is used to describe the first service data flow;

the packet flow description function network element is configured to: receive the query request; determine a correspondence between a first APP ID and a first packet flow description (PFD) that matches the signature parameter, as an APP ID corresponding to the first service data flow; and, responsive to determining the correspondence between the first APP ID and the first PFD, send a query response to the first network element, wherein the query response comprises the first APP ID; and

the first network element is further configured to receive the query response from the packet flow description function network element,

wherein the packet flow description function network element is further configured to:

match the signature parameter with at least one PFD, to determine that the first PFD matches the signature parameter; and

determine, based on the first PFD and the correspondence between the first PFD and the first APP ID, the first APP ID as the APP ID corresponding to the first service data flow.

11. The system of claim 10 , wherein the packet flow description function network element is further configured to:

before matching the signature parameter with the at least one PFD, determine that a correspondence between the signature parameter and an APP ID does not exist.

12. The system of claim 10 , wherein the packet flow description function network element is further configured to:

store a correspondence between the signature parameter and the first APP ID.

13. The system of claim 10 , wherein the first network element is a user plane network element.

14. The system of claim 10 , wherein the first network element is a session management network element, and the system further comprises a user plane network element and wherein:

the user plane network element is configured to send a first request to the first network element, wherein the first request comprises the signature parameter; and

the first network element is further configured to send a first response to the user plane network element, wherein the first response comprises the first APP ID.

15. The system of claim 10 , wherein:

the packet flow description function network element is deployed in a network exposure function network element.

16. A packet flow description function network element comprising:

at least one processor; and

a memory coupled to the at least one processor and having instructions stored thereon which, when executed by the at least one processor, cause the packet flow description function network element to:

receive a query request, wherein the query request comprises a signature parameter of a first service data flow, and the signature parameter is used to describe the first service data flow;

determine a correspondence between a first APP ID and a first packet flow description (PFD) that matches the signature parameter, as an APP ID corresponding to the first service data flow; and

responsive to determining the correspondence between the first APP ID and the first PFD, send a query response, wherein the query response comprises the first APP

wherein the instructions further cause the packet flow description function network element to:

determine that a correspondence between the signature parameter and an APP ID does not exist before matching the signature parameter with the at least one PFD.

17. The packet flow description function network element of claim 16 , wherein the instructions further cause the packet flow description function network element to:

match the signature parameter with at least one PFD to determine that the first PFD matches the signature parameter; and

determine, based on the first PFD and the correspondence between the first PFD and first APP ID, the first APP ID as the APP ID corresponding to the first service data flow.