Communication method and apparatus

Abstract

A communication method and apparatus. In the communication method, a first network element receives first information and a first service identifier from an application function network element, the first information being used for indicating server rediscovery. The first network element sends the first service identifier to a second network element. The first network element receives a domain name or an address corresponding to the first service identifier from the second network element. The first network element sends a first message to a terminal device, the first message comprising the domain name or the address corresponding to the first service identifier, and the first message being used for instructing the terminal device to clear server information corresponding to the domain name or the address corresponding to the first service identifier. The method enables the terminal device to clear the server information corresponding to the domain name or the address corresponding to the first service identifier, so that the terminal device obtains a new application server and the new application server provides a service to the terminal device, improving the service quality of the terminal device.

Description

Communication method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on January 11, 2024, with application number 202410047112.6 and application name “Communication Method and Device,” the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0003] With the growth of mobile service traffic, the industry has proposed the concept of edge computing (EC). By moving user plane functions and service processing capabilities to the edge of the network, EC can bring devices with these functions and service processing capabilities closer to end devices, thereby shortening the backhaul network distance and reducing the end-to-end (E2E) latency and jitter of user packets.

[0004] In edge computing scenarios, a terminal device can obtain the address of an EAS close to the terminal device through the edge application server (EAS) discovery process, allowing the terminal device to access the EAS close to the terminal device. When the EAS accessed by the terminal device is overloaded, the quality of service provided by the EAS to the terminal device degrades. Summary of the Invention

[0005] The embodiments of the present application provide a communication method and apparatus that are conducive to improving the service quality of terminal equipment.

[0006] In the first aspect, the present application provides a communication method, which can be applied to a first network element, a chip in the first network element, and a logic module or software that can realize all or part of the functions of the first network element. The following description takes the first network element as an example. The method includes: the first network element receives first information and a first service identifier from an application function network element, and the first information is used to instruct the server to rediscover. The first network element sends the first service identifier to the second network element. The first network element receives the domain name or address corresponding to the first service identifier from the second network element. The first network element sends a first message to the terminal device, the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

[0007] It can be seen that in this method, the first network element obtains the domain name or address corresponding to the first service identifier from the second network element, and then the first network element sends a first message to the terminal device, so that the terminal device clears the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device obtains the address of the new server, and then the new server provides services to the terminal device to improve the service quality of the terminal device.

[0008] In an optional embodiment, the server is an edge application server. The first information is specifically used to instruct the edge application server to rediscover, and the first message is specifically used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0009] In an optional manner, the domain name corresponding to the first service identifier is: the domain name of the edge application server corresponding to the first service identifier. The address corresponding to the first service identifier is: the address of the edge application server corresponding to the first service identifier.

[0010] In an optional implementation, the first network element sends the first service identifier to the second network element, including: the first network element sends the first service identifier to the second network element when a first condition is met; the first condition includes: the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier.

[0011] In an optional embodiment, the method further includes: the first network element receiving a data network access identifier corresponding to the first information from the application function network element. The first network element sending the first service identifier to the second network element includes: the first network element sending the first service identifier to the second network element when a second condition is met; the second condition includes: the server deployment information of the first network element does not include the data network access identifier.

[0012] In an optional implementation, the first network element belongs to a home public land mobile network of the terminal device, and the second network element belongs to a visited public land mobile network of the terminal device. The first network element sending the first service identifier to the second network element includes: the first network element sending the first service identifier to the second network element when a third condition is met; the third condition includes: the first network element does not store server deployment information of the visited public land mobile network.

[0013] In an optional embodiment, the method further includes: the first network element receiving third information from the second network element, the third information being used to indicate a data network access identifier supported by the second network element; and the first network element receiving the data network access identifier corresponding to the first information from the application function network element. The first network element sending the first service identifier to the second network element includes: the first network element sending the first service identifier to the second network element if a fourth condition is met; the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

[0014] In an optional implementation, the method further includes: the first network element sending fourth information to the second network element, where the fourth information is used to request a domain name or address corresponding to the first service identifier.

[0015] In an optional implementation, the first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

[0016] In an optional implementation, the first network element and the second network element serve the terminal device. In addition, the first network element and the second network element serving the terminal device can also be understood as: a session between the first network element and the second network element serving the terminal device.

[0017] In an optional manner, when the domain name or address corresponding to the first service identifier received by the first network element from the second network element is empty, or when the first network element receives information from the second network element indicating that the domain name or address corresponding to the first service identifier cannot be obtained, the first message sent by the first network element to the terminal device is used to instruct the terminal device to clear server information related to a first session, where the first session is used for the terminal device to access the service corresponding to the first service identifier. Furthermore, in this case, the domain name or address corresponding to the first service identifier sent by the first network element to the terminal device is empty, or the first network element does not send the domain name or address corresponding to the first service identifier to the terminal device.

[0018] In an optional manner, the first network element receives the first information and the first service identifier from the application function network element, which may be: the first network element receives the first information and the first service identifier from the application function network element through forwarding by the intermediate network element. Exemplarily, the intermediate network element may directly forward the first information and the first service identifier from the application function network element to the first network element. Alternatively, the intermediate network element generates a new message based on the first information and the first service identifier received from the application function network element, and sends the message to the first network element. Optionally, the intermediate network element may also modify the form of the first information and / or the first service identifier, and the intermediate network element may send the modified first information and / or the modified first service identifier to the first network element.

[0019] In an optional manner, the intermediate network element may be a policy control function (PCF) network element, which receives the first information and the first service identifier from the application function network element, and creates a policy and charging control rule (PCC rule) based on the received first information and the first service identifier. The policy control function network element sends the policy and charging control rule to the first network element, and the policy and charging control rule includes ninth information and the first service identifier. The ninth information is determined based on the first information, and the ninth information may be the same as or different from the first information, but the ninth information and the first information both serve to instruct the server to rediscover.

[0020] In an optional manner, the intermediate network element may be a policy control function network element and a network exposure function (NEF) network element. Exemplarily, the policy control function network element may directly receive the first information and the first service identifier from the application function network element, or indirectly receive the first information and the first service identifier from the application function network element through the network exposure function network element.

[0021] Optionally, the policy control function network element and the network open function network element may also forward information through a unified data repository (UDR). Exemplarily, the network open function network element stores the first information and the first service identifier received from the application function network element in the unified data repository, and the policy control function network element obtains the first information and the first service identifier from the unified data repository.

[0022] In an optional manner, the first information may be an "EAS relocation indication," and the first service identifier may be one or more "service IDs (application identifier, APP ID)." The ninth information may be the same as the first information. Alternatively, the ninth information may be different from the first information, and the ninth information may be an "EAS rediscovery indication (or, Indication of EAS rediscovery)." The first service identifier may be part of a "service data flow template" in a PCC rule.

[0023] In an optional manner, the first message includes second information, and the second information is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier. For example, the second information can be an "EAS rediscovery indication", and the domain name or address corresponding to the first service identifier can be sent to the terminal device as an impact field.

[0024] In one optional manner, instructing the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier may include instructing the terminal device to clear cached server information, where the domain name or address corresponding to the first service identifier indicates the server information to be cleared. Furthermore, "clear" may be replaced with "delete," "refresh," or the like.

[0025] In a second aspect, the present application provides a communication method that can be applied to a second network element, a chip in the second network element, or a logic module or software that implements all or part of the functions of the second network element. The following description uses the second network element as an example. The method includes: the second network element receiving a first service identifier from a first network element. Based on stored server deployment information, the second network element sends a domain name or address corresponding to the first service identifier to the first network element.

[0026] It can be seen that in this method, the second network element provides the first network element with the domain name or address corresponding to the first service identifier, so that the first network element instructs the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier, thereby enabling the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device can obtain the address of the new server, and then the new server provides services to the terminal device to improve the service quality of the terminal device.

[0027] In an optional implementation, the server is an edge application server.

[0028] In an optional manner, the method further includes: the second network element determining the domain name or address corresponding to the first service identifier based on the stored server deployment information.

[0029] In an optional manner, the domain name corresponding to the first service identifier is: the domain name of the server corresponding to the first service identifier. The address corresponding to the first service identifier is: the address of the server corresponding to the first service identifier.

[0030] In an optional implementation, the method further includes: the second network element receiving fourth information from the first network element, where the fourth information is used to request a domain name or address corresponding to the first service identifier.

[0031] In an optional implementation, the first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

[0032] In an optional implementation, the first network element and the second network element serve the terminal device. In addition, the first network element and the second network element serving the terminal device can also be understood as: a session between the first network element and the second network element serving the terminal device.

[0033] On the third aspect, the present application provides a communication method, which can be applied to a first network element, a chip in the first network element, and a logic module or software that can realize all or part of the functions of the first network element. The following description takes the first network element as an example. The method includes: the first network element receives fifth information from the second network element, and the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address. The first network element receives first information and the first service identifier from the application function network element, and the first information is used to indicate the rediscovery of the edge application server. Based on the fifth information and the first service identifier, the first network element sends a first message to the terminal device, the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

[0034] It can be seen that through this method, the first network element sends a first message to the terminal device, so that the terminal device clears the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device obtains the address of the new server, and then the new server provides services to the terminal device to improve the service quality of the terminal device.

[0035] In an optional embodiment, the server is an edge application server. The first information is specifically used to instruct the edge application server to rediscover, and the first message is specifically used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier. In an optional manner, the domain name corresponding to the first service identifier is: the domain name of the server corresponding to the first service identifier. The address corresponding to the first service identifier is: the address of the server corresponding to the first service identifier.

[0036] In an optional embodiment, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: when the first condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier; the first condition includes: the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier.

[0037] In an optional embodiment, the method further includes: the first network element receiving a data network access identifier corresponding to the first information from the application function network element. The first network element sending, based on the fifth information and the first service identifier, the second information and the domain name or address corresponding to the first service identifier to the terminal device, including: the first network element sending, based on the fifth information and the first service identifier, the second information and the domain name or address corresponding to the first service identifier to the terminal device when a second condition is met; the second condition including: the server deployment information of the first network element does not include the data network access identifier.

[0038] In an optional implementation, the first network element belongs to a home public land mobile network of the terminal device, and the second network element belongs to a visited public land mobile network of the terminal device. The first network element sends, based on the fifth information and the first service identifier, the second information and a domain name or address corresponding to the first service identifier to the terminal device, including: the first network element sends, based on the fifth information and the first service identifier, the second information and the domain name or address corresponding to the first service identifier to the terminal device when a third condition is met; the third condition includes: the first network element does not store server deployment information of the visited public land mobile network.

[0039] In an optional embodiment, the method further includes: the first network element receiving third information from the second network element, the third information being used to indicate a data network access identifier supported by the second network element; and the first network element receiving the data network access identifier corresponding to the first information from the application function network element. The first network element sending the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: the first network element sending the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier when a fourth condition is met; the fourth condition including: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

[0040] In an optional implementation, the first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

[0041] In an optional implementation, the first network element and the second network element serve the terminal device. In addition, the first network element and the second network element serving the terminal device can also be understood as: a session between the first network element and the second network element serving the terminal device.

[0042] In an optional manner, the first network element receives the first information and the first service identifier from the application function network element. Reference may also be made to the description of the optional manner of "the first network element receives the first information and the first service identifier from the application function network element" in the first aspect. For example, the first network element receives the first information and the first service identifier from the application function network element via forwarding by an intermediate network element. Furthermore, reference may also be made to the description of the first aspect regarding optional manners for the intermediate network element, the first information, the first service identifier, the first message, and the like, and no further elaboration is given.

[0043] In a fourth aspect, the present application provides a communication method, which can be applied to a second network element, a chip in the second network element, or a logic module or software that can implement all or part of the functions of the second network element. The following description takes the second network element as an example. The method includes: the second network element receives a domain name or address from an edge application server discovery function network element. Based on the domain name or address, the second network element sends fifth information to the first network element, where the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address.

[0044] It can be seen that in this method, the second network element provides the fifth information to the first network element, so that the first network element instructs the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device clears the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device obtains the address of the new server, and then the new server provides services to the terminal device to improve the service quality of the terminal device. In an optional implementation, the server is an edge application server.

[0045] In an optional manner, the second network element sends the fifth information to the first network element based on the domain name or address, including: the second network element sends the fifth information to the first network element based on the domain name or address and the stored server deployment information.

[0046] In an optional manner, the method further includes: the second network element determining the first service identifier corresponding to the domain name or address based on the stored server deployment information.

[0047] In an optional manner, the domain name corresponding to the first service identifier is: the domain name of the server corresponding to the first service identifier. The address corresponding to the first service identifier is: the address of the server corresponding to the first service identifier.

[0048] In an optional embodiment, the second network element sends the fifth information to the first network element based on the domain name or address, including: the second network element sends the fifth information to the first network element based on the domain name or address when the fifth condition is met; the fifth condition includes: the second network element has stored the identifier of the access and mobility management function network element.

[0049] In an optional embodiment, the second network element sends the fifth information to the first network element based on the domain name or address, including: the second network element sends the fifth information to the first network element based on the domain name or address when the sixth condition is met; the sixth condition includes: the second network element has not sent the correspondence between the first service identifier and the domain name to the first network element, and the second network element has not sent the correspondence between the first service identifier and the address to the first network element.

[0050] In an optional implementation, the first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

[0051] In an optional implementation, the first network element and the second network element serve the terminal device. In addition, the first network element and the second network element serving the terminal device can also be understood as: a session between the first network element and the second network element serving the terminal device.

[0052] In a fifth aspect, the present application provides a communication method, which can be applied to a first network element, a chip in the first network element, and a logic module or software that can realize all or part of the functions of the first network element. The following description is taken as an example of the first network element. The method includes: the first network element receives first information and a first service identifier from an application function network element, and the first information is used to instruct the server to rediscover. The first network element sends sixth information to the application function network element, and the sixth information is used to request the domain name or address corresponding to the first service identifier. The first network element receives the domain name or address corresponding to the first service identifier from the application function network element. The first network element sends a first message to the terminal device, and the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

[0053] It can be seen that in this method, the first network element obtains the domain name or address corresponding to the first service identifier from the application function network element, and then the first network element sends a first message to the terminal device, so that the terminal device clears the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device obtains the address of the new server, and then the new server provides services to the terminal device to improve the service quality of the terminal device.

[0054] In an optional embodiment, the server is an edge application server. The first information is specifically used to instruct the edge application server to rediscover, and the first message is specifically used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0055] In an optional manner, the domain name corresponding to the first service identifier is: the domain name of the server corresponding to the first service identifier. The address corresponding to the first service identifier is: the address of the server corresponding to the first service identifier.

[0056] In an optional implementation, the first network element sends the sixth information to the application function network element, including: the first network element sends the sixth information to the application function network element when the first condition is met; the first condition includes: the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier.

[0057] In an optional embodiment, the method further includes: the first network element receiving a data network access identifier corresponding to the first information from the application function network element. The first network element sending sixth information to the application function network element includes: the first network element sending the sixth information to the application function network element if a second condition is met; the second condition includes: the server deployment information of the first network element does not include the data network access identifier.

[0058] In an optional implementation, the first network element belongs to a home public land mobile network of the terminal device, and the second network element belongs to a visited public land mobile network of the terminal device. The first network element sending the sixth information to the application function network element includes: the first network element sending the sixth information to the application function network element when a third condition is met; the third condition includes: the first network element does not store server deployment information of the visited public land mobile network.

[0059] In an optional embodiment, the method further includes: the first network element receiving third information from the second network element, the third information being used to indicate a data network access identifier supported by the second network element; and the first network element receiving the data network access identifier corresponding to the first information from the application function network element. The first network element sending sixth information to the application function network element includes: the first network element sending the sixth information to the application function network element if a fourth condition is met; the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

[0060] In an optional implementation, the first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

[0061] In an optional implementation, the first network element and the second network element serve the terminal device. In addition, the first network element and the second network element serving the terminal device can also be understood as: a session between the first network element and the second network element serving the terminal device.

[0062] In an optional manner, the first network element receives the first information and the first service identifier from the application function network element. Reference may also be made to the description of the optional manner of "the first network element receives the first information and the first service identifier from the application function network element" in the first aspect. For example, the first network element receives the first information and the first service identifier from the application function network element via forwarding by an intermediate network element. Furthermore, reference may also be made to the description of the first aspect regarding optional manners for the intermediate network element, the first information, the first service identifier, the first message, and the like, and no further elaboration is given.

[0063] In a sixth aspect, the present application provides a communication method, which can be applied to an application function network element, a chip in an application function network element, or a logic module or software that can realize all or part of the functions of the application function network element. The following description is taken as an example of an application function network element. The method includes: the application function network element sends first information and a first service identifier to a first network element, and the first information is used to instruct the edge application server to rediscover. The application function network element receives sixth information from the first network element, and the sixth information is used to request a domain name or address corresponding to the first service identifier. The application function network element sends a domain name or address corresponding to the first service identifier to the first network element.

[0064] It can be seen that in this method, the application function network element sends the domain name or address corresponding to the first service identifier to the first network element, so that the first network element instructs the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device clears the server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device obtains the address of the new server, and then the new server provides services to the terminal device to improve the service quality of the terminal device.

[0065] In an optional implementation, the server is an edge application server. The first information is specifically used to instruct the edge application server to rediscover.

[0066] In an optional manner, the application function network element sends the first information and the first service identifier to the first network element, which may be: the application function network element sends the first information and the first service identifier to the first network element through the intermediate network element. Exemplarily, the intermediate network element may directly forward the first information and the first service identifier from the application function network element to the first network element. Alternatively, the intermediate network element generates a new message based on the first information and the first service identifier received from the application function network element, and sends the message to the first network element. Optionally, the intermediate network element may also modify the form of the first information and / or the first service identifier, and the intermediate network element sends the modified first information and / or the modified first service identifier to the first network element.

[0067] In addition, regarding the optional methods of the intermediate network element, the first information, the first service identifier, etc., reference can be made to the description in the first aspect and will not be repeated here.

[0068] In an optional manner, the application function network element sends the domain name or address corresponding to the first service identifier to the first network element. This may be done by: the application function network element sends the domain name or address corresponding to the first service identifier to the first network element via an intermediate network element. This is similar to the aforementioned sending of the first information and the first service identifier by the first network element to the first network element, and is not further described.

[0069] In an optional manner, the domain name corresponding to the first service identifier is: the domain name of the edge application server corresponding to the first service identifier. The address corresponding to the first service identifier is: the address of the edge application server corresponding to the first service identifier.

[0070] In the seventh aspect, the present application provides a communication method, which can be applied to a first network element, a chip in the first network element, and a logic module or software that can realize all or part of the functions of the first network element. The following description takes the first network element as an example. The method includes: the first network element receives first information and a first service identifier from an application function network element, and the first information is used to instruct the server to rediscover. When the first network element cannot obtain the domain name or address corresponding to the first service identifier, the second information is sent to the terminal device, and the second information is used to instruct the terminal device to clear all server information related to the first session, and the first session is used for the terminal device to access the service corresponding to the first service identifier.

[0071] In an optional embodiment, the server is an edge application server. The first information is specifically used to instruct the edge application server to rediscover, and the second information is specifically used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0072] In an optional manner, the situation where the first network element cannot obtain the domain name or address corresponding to the first service identifier includes:

[0073] The server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier; or,

[0074] The first network element does not store the server deployment information of the visited public land mobile network; or,

[0075] The server deployment information of the first network element does not include a data network access identifier; or,

[0076] The data network access identifier corresponding to the first information is a data network access identifier supported by the second network element; or,

[0077] The first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element; or,

[0078] The first network element is a session management function network element, and the second network element is an intermediate session management function network element; or,

[0079] The first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server related information.

[0080] In one optional manner, the first network element receives the first information and the first service identifier from the application function network element. Reference may also be made to the description of the optional manner of "the first network element receives the first information and the first service identifier from the application function network element" in the first aspect. For example, the first network element receives the first information and the first service identifier from the application function network element via forwarding by an intermediate network element. Furthermore, reference may also be made to the description of the first aspect regarding optional manners for the intermediate network element, the first information, the first service identifier, the second information, and the like, and no further elaboration is given.

[0081] In an optional manner, in the expression of instructing the terminal device to clear all server information related to the first session, “clear” may also be replaced by “delete”, “refresh”, etc.

[0082] In an eighth aspect, the present application provides a communication method, the method comprising: a first network element receives first information and a first service identifier from an application function network element, the first information being used to instruct server rediscovery. The first network element sends the first service identifier to the second network element; the second network element receives the first service identifier from the first network element. The second network element sends the domain name or address corresponding to the first service identifier to the first network element based on the stored edge application server deployment information; the first network element receives the domain name or address corresponding to the first service identifier from the second network element. The first network element sends a first message to a terminal device, the first message including the domain name or address corresponding to the first service identifier, the first message being used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0083] In addition, in this aspect, other optional implementations included in the method can refer to the relevant contents of the first and second aspects mentioned above, and also have the beneficial effects described in the first and second aspects, which will not be described in detail here.

[0084] In a ninth aspect, the present application provides a communication method, which includes: the second network element receives a domain name or address from an edge application server discovery function network element. Based on the domain name or address, the second network element sends fifth information to the first network element, and the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address; the first network element receives the fifth information from the second network element. The first network element receives the first information and the first service identifier from the application function network element, and the first information is used to instruct the edge application server to rediscover. Based on the fifth information and the first service identifier, the first network element sends a first message to the terminal device, the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0085] In addition, in this aspect, other optional implementations included in the method can refer to the relevant contents of the third and fourth aspects mentioned above, and also have the beneficial effects described in the third and fourth aspects, which will not be described in detail here.

[0086] In a tenth aspect, the present application provides a communication method, the method comprising: an application function network element sends first information and a first service identifier to a first network element, the first information being used to instruct an edge application server to rediscover; the first network element receives the first information and the first service identifier from the application function network element. The first network element sends sixth information to the application function network element, the sixth information being used to request a domain name or address corresponding to the first service identifier; the application function network element receives the sixth information from the first network element. The application function network element sends a domain name or address corresponding to the first service identifier to the first network element; the first network element receives the domain name or address corresponding to the first service identifier from the application function network element. The first network element sends a first message to a terminal device, the first message including a domain name or address corresponding to the first service identifier, the first message being used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0087] In addition, in this aspect, other optional implementations included in the method can refer to the relevant contents of the fifth and sixth aspects mentioned above, and also have the beneficial effects described in the fifth and sixth aspects, which will not be described in detail here.

[0088] In an eleventh aspect, the present application provides a communication system, comprising a first network element and a second network element. In another possible design, the system may further include other devices that interact with the first network element in the solution provided by the present application, and / or other devices that interact with the second network element.

[0089] In one embodiment, a first network element is used to receive first information and a first service identifier from an application function network element, and the first information is used to instruct an edge application server to rediscover. The first network element is also used to send the first service identifier to a second network element. The second network element is used to receive the first service identifier from the first network element. The second network element is also used to send a domain name or address corresponding to the first service identifier to the first network element based on the stored edge application server deployment information. The first network element is also used to receive a domain name or address corresponding to the first service identifier from the second network element. The first network element is also used to send a first message to a terminal device, the first message including a domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0090] In addition, in this aspect, other optional implementation methods of the first network element can refer to the relevant content of the above-mentioned first aspect, and other optional implementation methods of the second network element can refer to the relevant content of the above-mentioned second aspect, which will not be described in detail here.

[0091] In another embodiment, the second network element is used to receive a domain name or address from an edge application server discovery function network element. The second network element is also used to send fifth information to the first network element based on the domain name or address, and the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address. The first network element is used to receive the fifth information from the second network element. The first network element is also used to receive the first information and the first service identifier from the application function network element, and the first information is used to instruct the edge application server to rediscover. The first network element is also used to send a first message to the terminal device based on the fifth information and the first service identifier, and the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0092] In addition, in this aspect, other optional implementation methods of the first network element can refer to the relevant content of the third aspect above, and other optional implementation methods of the second network element can refer to the relevant content of the fourth aspect above, which will not be described in detail here.

[0093] In a twelfth aspect, the present application provides a communication system, the system comprising an application function network element and a first network element. In another possible design, the system may further include other devices that interact with the application function network element in the solution provided by the present application, and / or other devices that interact with the first network element.

[0094] Among them, the application function network element is used to send the first information and the first service identifier to the first network element, and the first information is used to instruct the edge application server to rediscover. The first network element is used to receive the first information and the first service identifier from the application function network element. The first network element is also used to send the sixth information to the application function network element, and the sixth information is used to request the domain name or address corresponding to the first service identifier. The application function network element is also used to receive the sixth information from the first network element. The application function network element is also used to send the domain name or address corresponding to the first service identifier to the first network element. The first network element is also used to receive the domain name or address corresponding to the first service identifier from the application function network element. The first network element is also used to send a first message to the terminal device, the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0095] In addition, in this aspect, other optional implementation methods of the first network element can refer to the relevant content of the fifth aspect above and will not be described in detail here.

[0096] In a thirteenth aspect, the present application further provides a communication device. The communication device may be a first network element, a chip within the first network element, or a logic module or software capable of implementing all or part of the functions of the first network element. The communication device has the functionality to implement some or all of the implementations described in the first, third, fifth, or seventh aspects above. Alternatively, the communication device may be a second network element, a chip within the second network element, or a logic module or software capable of implementing all or part of the functions of the second network element. The communication device has the functionality to implement some or all of the implementations described in the second or fourth aspects above. Alternatively, the communication device may be an application function network element, a chip within the application function network element, or a logic module or software capable of implementing all or part of the functions of the application function network element. The communication device has the functionality to implement some or all of the implementations described in the sixth aspect above. The functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the functions described above.

[0097] In one possible design, the communication device may include a processing unit configured to support the communication device in executing the corresponding functions in the above method. Optionally, the communication device may also include a communication unit configured to support communication between the communication device and other communication devices. Optionally, the communication device may also include a storage unit coupled to the processing unit and the communication unit to store program instructions and data necessary for the communication device. In addition, the processing unit may be used to control the communication unit to transmit and receive data / signaling.

[0098] In one embodiment, a communication unit is configured to receive first information and a first service identifier from an application function network element, the first information being configured to instruct an edge application server to rediscover. The communication unit is further configured to send the first service identifier to a second network element. The communication unit is further configured to receive a domain name or address corresponding to the first service identifier from the second network element. The communication unit is further configured to send a first message to a terminal device, the first message including the domain name or address corresponding to the first service identifier, the first message being configured to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0099] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the first aspect above and will not be described in detail here.

[0100] In another embodiment, the communication unit is configured to receive the first service identifier from the first network element and to send the domain name or address corresponding to the first service identifier to the first network element based on the stored edge application server deployment information.

[0101] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the second aspect above and will not be described in detail here.

[0102] In another embodiment, the communication unit is used to receive fifth information from the second network element, the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address. The communication unit is also used to receive first information and the first service identifier from the application function network element, the first information is used to indicate edge application server rediscovery. The communication unit is also used to send a first message to the terminal device based on the fifth information and the first service identifier, the first message including the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0103] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the third aspect above and will not be described in detail here.

[0104] In another embodiment, the communication unit is configured to receive a domain name or address from an edge application server discovery function network element. The communication unit is further configured to send fifth information to the first network element based on the domain name or address, where the fifth information is configured to indicate a correspondence between the first service identifier and the domain name, or the fifth information is configured to indicate a correspondence between the first service identifier and the address.

[0105] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the fourth aspect above and will not be described in detail here.

[0106] In another embodiment, the communication unit is used to receive first information and a first service identifier from an application function network element, the first information being used to instruct the edge application server to rediscover. The communication unit is also used to send sixth information to the application function network element, the sixth information being used to request the domain name or address corresponding to the first service identifier. The communication unit is also used to receive the domain name or address corresponding to the first service identifier from the application function network element. The communication unit is also used to send a first message to the terminal device, the first message including the domain name or address corresponding to the first service identifier, the first message being used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0107] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the fifth aspect above and will not be described in detail here.

[0108] In another embodiment, the communication unit is configured to send first information and a first service identifier to a first network element, where the first information is used to instruct the edge application server to rediscover the service. The communication unit is further configured to receive sixth information from the first network element, where the sixth information is used to request a domain name or address corresponding to the first service identifier. The communication unit is further configured to send the domain name or address corresponding to the first service identifier to the first network element.

[0109] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the sixth aspect mentioned above and will not be described in detail here.

[0110] As an example, the communication unit may be a transceiver or a communication interface, the storage unit may be a memory, and the processing unit may be a processor. The processor is coupled to the memory, the memory is used to store programs or instructions to the processor, and the processor is configured to cause the communication device to perform the method described in the first aspect when the programs or instructions are executed by the processor. The transceiver or communication interface may be configured to transmit and receive signals and / or data.

[0111] In one embodiment, a transceiver is configured to receive first information and a first service identifier from an application function network element, the first information being used to instruct an edge application server to rediscover. The transceiver is further configured to send the first service identifier to a second network element. The transceiver is further configured to receive a domain name or address corresponding to the first service identifier from the second network element. The transceiver is further configured to send a first message to a terminal device, the first message including the domain name or address corresponding to the first service identifier, the first message being used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0112] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the first aspect above and will not be described in detail here.

[0113] In another embodiment, the transceiver is configured to receive a first service identifier from a first network element and to send a domain name or address corresponding to the first service identifier to the first network element based on the stored edge application server deployment information.

[0114] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the second aspect above and will not be described in detail here.

[0115] In another embodiment, the transceiver is configured to receive fifth information from a second network element, the fifth information being used to indicate a correspondence between a first service identifier and a domain name, or the fifth information being used to indicate a correspondence between a first service identifier and an address. The transceiver is further configured to receive first information and a first service identifier from an application function network element, the first information being used to instruct an edge application server to rediscover the edge application server. The transceiver is further configured to send a first message to a terminal device based on the fifth information and the first service identifier, the first message including a domain name or address corresponding to the first service identifier, the first message being used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0116] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the third aspect above and will not be described in detail here.

[0117] In another embodiment, the transceiver is configured to receive a domain name or address from an edge application server discovery function network element. The transceiver is further configured to send fifth information to the first network element based on the domain name or address, where the fifth information is configured to indicate a correspondence between the first service identifier and the domain name, or the fifth information is configured to indicate a correspondence between the first service identifier and the address.

[0118] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the fourth aspect above and will not be described in detail here.

[0119] In another embodiment, the transceiver is configured to receive first information and a first service identifier from an application function network element, the first information being used to instruct an edge application server to rediscover. The transceiver is further configured to send sixth information to the application function network element, the sixth information being used to request a domain name or address corresponding to the first service identifier. The transceiver is further configured to receive a domain name or address corresponding to the first service identifier from the application function network element. The transceiver is further configured to send a first message to a terminal device, the first message including a domain name or address corresponding to the first service identifier, the first message being used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0120] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the fifth aspect above and will not be described in detail here.

[0121] In another embodiment, the transceiver is configured to send first information and a first service identifier to a first network element, where the first information is used to instruct the edge application server to rediscover the service. The transceiver is further configured to receive sixth information from the first network element, where the sixth information is used to request a domain name or address corresponding to the first service identifier. The transceiver is further configured to send the domain name or address corresponding to the first service identifier to the first network element.

[0122] In addition, in this aspect, other optional implementations of the communication device can be found in the relevant content of the sixth aspect above and will not be described in detail here. In another implementation, the communication device is a chip or a chip system. The processing unit can also be embodied as a processing circuit or a logic circuit; the transceiver unit can be an input / output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip or chip system.

[0123] During implementation, the processor can be used to perform, for example, but not limited to, baseband-related processing, and the transceiver or communication interface can be used to perform, for example, but not limited to, radio frequency transceiver. The above-mentioned devices can be provided on separate chips, or at least partially or entirely on the same chip. For example, the processor can be further divided into an analog baseband processor and a digital baseband processor. The analog baseband processor can be integrated with the transceiver (or communication interface) on the same chip, while the digital baseband processor can be provided on a separate chip. With the continuous development of integrated circuit technology, more and more devices can be integrated on the same chip. For example, a digital baseband processor can be integrated with multiple application processors (such as, but not limited to, a graphics processor, a multimedia processor, etc.) on the same chip. Such a chip can be called a system on a chip (SoC). Whether each device is provided independently on different chips or integrated on one or more chips often depends on the needs of the product design. The embodiments of the present application do not limit the implementation form of the above-mentioned devices.

[0124] In the fourteenth aspect, the present application also provides a processor for executing the various methods mentioned above. In the process of executing these methods, the process of sending the above information and receiving the above information in the above method can be understood as the process of the processor outputting the above information, and the process of the processor inputting the above information. When outputting the above information, the processor outputs the above information to the transceiver so that it is transmitted by the transceiver (or communication interface). After being output by the processor, the above information may also need to undergo other processing before reaching the transceiver (or communication interface). Similarly, when the processor receives the input information, the transceiver (or communication interface) receives the above information and inputs it into the processor. Furthermore, after the transceiver (or communication interface) receives the above information, the above information may need to undergo other processing before being input into the processor.

[0125] For the sending and receiving operations involved in the processor, unless otherwise specified, or unless they conflict with their actual functions or internal logic in the relevant descriptions, they can be more generally understood as processor output, reception, input and other operations, rather than sending and receiving operations directly performed by the RF circuit and antenna.

[0126] During implementation, the processor may be a processor specifically configured to execute these methods, or may be a processor that executes computer instructions in a memory to execute these methods, such as a general-purpose processor. The memory may be a non-transitory memory, such as a read-only memory (ROM), which may be integrated with the processor on the same chip or disposed on separate chips. The embodiments of the present application do not limit the type of memory or the configuration of the memory and the processor.

[0127] In a fifteenth aspect, the present application provides a computer-readable storage medium storing a computer program. When the computer program is run, the method described in any one of the first to seventh aspects is executed.

[0128] In the sixteenth aspect, the present application further provides a computer program product comprising instructions, the computer program product comprising: computer program code, which, when the computer program code is run, enables the method described in any one of the above-mentioned first to seventh aspects to be executed.

[0129] In the seventeenth aspect, the present application provides a chip system, which includes a processor and an interface, wherein the interface is used to obtain a program or instruction, and the processor is used to call the program or instruction to implement the functions involved in any one of the first to seventh aspects. In one possible design, the chip system also includes a memory, which is used to store program instructions and data necessary for the terminal. The chip system can be composed of a chip, or it can include a chip and other discrete devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0130] FIG1 is a schematic diagram of a network architecture;

[0131] FIG2 is a schematic diagram of another network architecture;

[0132] FIG3 is a schematic diagram of a communication system provided in an embodiment of the present application;

[0133] FIG4 is a schematic diagram of another communication system provided in an embodiment of the present application;

[0134] FIG5 is a schematic diagram of another communication system provided in an embodiment of the present application;

[0135] FIG6 is a schematic diagram of another communication system provided in an embodiment of the present application;

[0136] 7 is a schematic diagram of an edge application server discovery process provided in an embodiment of the present application;

[0137] FIG8 is a flow chart of a communication method 100 provided in an embodiment of the present application;

[0138] FIG9 is a flow chart of a communication method 200 provided in an embodiment of the present application;

[0139] FIG10 is a flow chart of a communication method 300 provided in an embodiment of the present application;

[0140] FIG11 is a flow chart of a communication method 400 provided in an embodiment of the present application;

[0141] FIG12 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0142] FIG13 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0143] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0144] Before introducing the embodiments of the present application, the following points are first explained.

[0145] First, in this application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0146] It can be understood that some optional features in the embodiments of the present application may not depend on other features in certain scenarios, and may also be combined with other features in certain scenarios, without limitation.

[0147] It can be understood that the solutions in the embodiments of this application can be used in combination, and the explanations or descriptions of each term, similar operations or steps appearing in the embodiments can be referenced or explained with each other in each embodiment, and this application does not limit this.

[0148] Second, in this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b and c can represent: a, or b, or c, or a and b, or a and c, or b and c, or a, b and c. Wherein a, b and c can be single or multiple, respectively.

[0149] Third, throughout this application, the terms "first," "second," and various numerical references are used for descriptive purposes only and are not intended to limit the scope of the embodiments of this application. For example, they are used to distinguish between different messages, rather than to describe a specific order or precedence. It should be understood that these references are interchangeable, where appropriate, to allow for the description of scenarios beyond the embodiments of this application.

[0150] Fourth, in this application, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or are inherent to these processes, methods, products or apparatuses.

[0151] Fifth, in this application, "used to indicate" can include being used for direct indication and being used for indirect indication. When describing that a certain indication information is used to indicate A, it can include that the indication information directly indicates A or indirectly indicates A, and does not necessarily mean that the indication information carries A.

[0152] Sixth, in this application, "sending information to XX (device / network element)" can be understood as the destination of the information being the device. This can include sending information to the device directly or indirectly. "Receiving information from XX (device / network element) or receiving information from XX (device / network element)" can be understood as the source of the information being the device, which can include receiving information from the device directly or indirectly. The information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source.

[0153] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0154] The technical solutions of the embodiments of the present application can be applied to various communication systems. For example, the global mobile communication system, the long term evolution (LTE) system, the universal mobile communication system, the fourth generation (4G) mobile communication system, the fifth generation (5G) mobile communication system, and with the continuous development of communication technology, the technical solutions of the embodiments of the present application can also be used for subsequently evolved communication systems, such as the sixth generation (6G) mobile communication system, the seventh generation (7G) mobile communication system, and so on.

[0155] Please refer to Figure 1, which is a schematic diagram of a network architecture for a non-roaming scenario and a 5G network architecture based on a service-based interface. The network architecture includes a network repository function (NRF) network element, a policy control function (PCF) network element, an application function (AF) network element, a unified data management (UDM) network element, an access and mobility management function (AMF) network element, a session management function (SMF) network element, a network exposure function (NEF) network element, an edge application server discovery function (EASDF) network element, terminal equipment, an access network (AN), a user plane function (UPF) network element, and a data network (DN).

[0156] The service-oriented interface provided by the NRF network element is the Nnrf interface. The service-oriented interface provided by the PCF network element is the Npcf interface. The service-oriented interface provided by the AF network element is the Naf interface. The service-oriented interface provided by the UDM network element is the Nudm interface. The service-oriented interface provided by the AMF network element is the Namf interface. The service-oriented interface provided by the SMF network element is the Nsmf interface. The service-oriented interface provided by the NEF network element is the Nnef interface. The service-oriented interface provided by the EASDF network element is the Neasdf interface. Terminal devices and AMF network elements communicate through the N1 interface. The AN and AMF network elements communicate through the N2 interface. The AN and UPF network elements communicate through the N3 interface. The UPF network element communicates with the SMF network element through the N4 interface. The UPF network element communicates with the DN through the N6 interface.

[0157] Among them, the UPF network element serving as a diversion point can also be called an uplink classifier (ULCL) or a branching point (BP). The UPF network element serving as a diversion point communicates with the AN via the N3 interface. The UPF network element directly connected to the DN via the N6 interface in a protocol data unit (PDU) session can also be called a PDU session anchor (PSA). The central anchor point UPF can also be called a central PDU session anchor (C-PSA). The C-PAS communicates with the UPF network element serving as a diversion point via the N9 interface, and the C-PAS communicates with the central DN (central DN) via the N6 interface. The anchor point UPF for local diversion can also be called a local PDU session anchor (L-PSA). The L-PSA communicates with the local part of the DN via the N6 interface. The local part of the DN includes the edge application server (EAS). The local part of the DN can also be called a local DN.

[0158] In addition, the embodiments of the present application can also be applied to roaming scenarios. The networks in the roaming scenarios include a visited public land mobile network (VPLMN) and a home public land mobile network (HPLMN), wherein the HPLMN is a public land mobile network (PLMN) that the terminal device subscribes to in the home location, and the VPLMN is a PLMN that the terminal device accesses in the roaming location. When the terminal device leaves the coverage of the HPLMN, the terminal device can access the VPLMN, the coverage of which can include the current location of the terminal device, and the operator to which the VPLMN belongs has signed a roaming agreement with the operator to which the HPLMN belongs, so that the operator to which the VPLMN belongs can provide services and billing for the terminal device. It can be understood that in the roaming scenario, the service PLMN of the terminal device is the VPLMN.

[0159] Please refer to Figure 2, which is a schematic diagram of another network architecture, which is an exemplary network architecture for roaming scenarios, and is a 5G network architecture based on a service-oriented interface. The network architecture shown in Figure 2 includes VPLMN and HPLMN, wherein VPLMN includes NRF network element, PCF network element, AMF network element, SMF network element, NEF network element, EASDF network element, terminal equipment, AN, UL CL / BP, L-PAS, DN local part (including EAS), and HPLMN includes UDM network element, NRF network element, PCF network element, AF network element, SMF network element, NEF network element, C-PSA, and central DN. The interfaces used for network element communication in Figure 2 can be found in the relevant description of the network architecture shown in Figure 1 and will not be repeated here. In addition, in the embodiment of the present application, the "xx network element" in the VPLMN may also be referred to as the "visited xx network element" or the "visited domain xx network element." For example, the SMF network element in the VPLMN may also be referred to as a visited SMF network element or a visited domain SMF network element (V-SMF network element). The "xx network element" in the HPLMN may also be referred to as the "home xx network element" or the "home domain xx network element." For example, the SMF network element in the HPLMN may also be referred to as a home SMF network element or a home domain SMF network element (H-SMF network element).

[0160] In the embodiment of the present application, the terminal device may also be referred to as user equipment (UE), terminal, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, user agent or user device, and can be applied to 4G, 5G or even 6G systems, etc. The terminal device in the embodiment of the present application can be a joint device that transmits and receives digital signals on an ordinary telephone line, and can also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a mobile phone, a tablet computer (pad), a computer with wireless transceiver function, a head mounted display (HMD), a virtual reality (VR) terminal device (such as VR glasses), an augmented reality (AR) terminal device (such as AR glasses), a mixed reality (MR) terminal device, a wireless terminal in industrial control, a processing device connected to a wireless modem, a tactile terminal device, a vehicle-mounted terminal device, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a wireless terminal in a medical device ... home), the aforementioned wireless terminal type road side unit (RSU), wearable terminal equipment, etc.

[0161] The AN can be, for example, a radio access network (RAN). Access network equipment includes, but is not limited to, a base station (BS), a radio network controller (RNC), a base station controller (BSC), a base transceiver station (BTS), home network equipment (e.g., home evolved Node B, or home Node B, HNB), a baseband unit (BBU), a wireless relay node, a wireless backhaul node, and a transmission and reception point (TRP; or, transmission point, TP). A base station is a device deployed in a radio access network that can provide wireless communication functions. It can also be called a base station device, such as an evolved Node B (eNB or e-NodeB) in an LTE system, a Node B (Node B), a base station (gNodeB or gNB) in a 5G system, or a base station in a 6G system. A base station can include a BBU and a remote radio unit (RRU). BBU and RRU can be placed in different places, for example: RRU is remote and placed in an area with high traffic volume, and BBU is placed in a central computer room. BBU and RRU can also be placed in the same computer room. BBU and RRU can also be different components under one rack. Base stations can be in the following forms: macro base stations, micro base stations (also known as small stations), pico base stations, relay stations, access points, balloon stations, etc. Optionally, in some deployments of access network equipment, the access network equipment may include a centralized unit (CU) and a distributed unit (DU), etc. In other deployments of access network equipment, the CU can also be divided into a CU-control plane (CP) and a CU-user plane (UP), etc. In some other deployments of access network equipment, the access network equipment can also be an open radio access network (ORAN) architecture, etc. This application does not limit the specific deployment method of the access network equipment.

[0162] The AMF network element is responsible for the mobility management of terminal devices, including mobile state management, allocation of temporary identity identifiers for terminal devices, and authentication and authorization of terminal devices.

[0163] The UDM network element is responsible for managing contract data and notifying the corresponding network element when the contract data is modified.

[0164] The AF network element is used by service providers to indicate their needs to the core network and subscribe to user plane events. Service providers can provide EAS content.

[0165] The SMF network element is primarily responsible for session management in mobile networks, such as session establishment, modification, and release. Specific functions include allocating Internet Protocol (IP) addresses to users and selecting the UPF that provides packet forwarding capabilities.

[0166] Please refer to Figure 3, which is a schematic diagram of a communication system provided in an embodiment of the present application, wherein the communication system includes an application function network element, a first network element, a second network element, and a terminal device. Among them, different network elements / devices can communicate directly with each other, or can also communicate indirectly through other network elements / devices, and there is no limitation on this. Optionally, the communication system shown in Figure 3 may also include an edge application server discovery function network element, and the edge application server discovery function network element and the second network element can communicate directly, or can also communicate indirectly through other network elements / devices.

[0167] In an optional embodiment, the service areas of the first network element and the second network element are different. In the embodiment of the present application, the service areas of the first network element and the second network element are different, for example, the service area of ​​the first network element and the service area of ​​the second network element do not intersect, or the service area of ​​the first network element and the service area of ​​the second network element have an intersection and the intersection is not empty, or the service area of ​​the second network element is a subset of the service area of ​​the first network element. For example, in a non-roaming scenario, the service areas of the first network element and the second network element are different. For another example, in a roaming scenario, the service area of ​​the first network element belongs to the scope of the home public land mobile network, and the service area of ​​the second network element belongs to the scope of the visited public land mobile network.

[0168] In an optional implementation, the first network element and the second network element serve the terminal device. In the embodiment of the present application, the first network element and the second network element serve the terminal device, which can also be understood as: a session between the first network element and the second network element serving the terminal device.

[0169] In an optional embodiment, the first network element belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device. This method can be applied to roaming scenarios. Optionally, the first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element. Exemplarily, in a roaming scenario of a 5G system, the first network element can be an SMF network element in an HPLMN (i.e., an H-SMF network element), and the second network element can be an SMF network element in a VPLMN (i.e., a V-SMF network element), for example, as shown in the communication system of FIG4 .

[0170] In another optional implementation, the first network element is a session management function network element, and the second network element is an intermediate session management function network element. This approach can be applied to non-roaming scenarios. For example, in a 5G system, the first network element can be an SMF network element, and the second network element can be an intermediate SMF (I-SMF) network element, such as the communication system shown in Figure 5.

[0171] In another optional embodiment, the first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing information related to edge application servers. This approach can be applied to non-roaming scenarios. For example, the second network element can assist the first network element in completing edge application server discovery and session management to reduce the load on the first network element. In addition, in this embodiment, the second network element can be, for example, another session management function network element that assists the session management function network element. The second network element can also be, for example, a local network element, which can be, for example, a local session management function network element. However, the embodiments of the present application are not limited to the naming of the second network element in the case where the second network element is used to assist the session management function network element in processing information related to edge application servers. For example, in a 5G system, the first network element can be an SMF network element, and the second network element can be a local SMF (L-SMF) network element, for example, as shown in the communication system of Figure 6.

[0172] It is understandable that as the network architecture changes, the method provided in the embodiment of the present application can also be implemented by network elements with corresponding functions in the new network architecture.

[0173] It will be understood that for ease of explanation, the embodiments of the present application are described using the 5G system as an example. When the solutions of the embodiments of the present application are applied to the 6G system or other communication systems, the corresponding network element names, network element deployment methods, and interfaces may change, and this application does not limit this.

[0174] Next, a brief introduction is given to the relevant concepts involved in the embodiments of this application.

[0175] 1. Edge computing (EC)

[0176] Edge computing is a distributed computing model that enables local processing of distributed business traffic by moving user plane functions and business processing capabilities to the edge of the network.

[0177] In a network architecture that deploys user-plane devices in a tree topology, uplink user packets must pass through base stations, backhaul networks, and centrally deployed anchor gateways to access the data network. These anchor gateways are typically deployed at higher locations in the network (for example, in a regional central data center). This results in excessive traffic concentration at the anchor gateways when traffic is high. Compared to a network architecture that deploys user-plane devices in a tree topology, an edge computing-based network architecture can reduce excessive traffic concentration at anchor gateways, thereby lowering the requirements for backhaul network bandwidth, data center throughput, and gateway specifications.

[0178] Moreover, by moving user-plane functions and service processing capabilities down to the edge of the network, edge computing can bring devices with user-plane functions and service processing capabilities closer to terminal devices, thereby shortening the distance of the backhaul network and reducing the end-to-end (E2E) latency and jitter of user messages. The network architectures shown in Figures 1, 2, 4, 5, and 6 are all network architectures deployed using edge computing. For example, in the network architecture described in Figure 1, the UPF network element is deployed at the edge of the network, and the user-plane path is for the terminal device to access the DN through the AN and UPF network elements, which can reduce the E2E latency and jitter of the user message.

[0179] 2. Edge application server discovery

[0180] The edge application server discovery process can be used to return an edge application server address (e.g., an EAS IP address) to the terminal device when the terminal device initiates a domain name service (DNS) query. The edge application server discovery process can also be used to enable data packets exchanged between the terminal device and the edge application server to be forwarded through a local path on the user plane, where the user plane local path is configured by the session management function network element and the user plane local path includes the path from ULCL / BP to L-PSA. After the edge application server discovery process is completed, the terminal device can access the edge application server through the user plane local path.

[0181] For example, in conjunction with FIG7 , the edge application server discovery process may include: if a terminal device wishes to access an edge service, the terminal device sends a DNS query message. The DNS query message carries the domain name the terminal device wishes to access, such as a fully qualified domain name (FQDN). The edge application server discovery function element sends partial information from the DNS query message to the session management function element. The partial information in the DNS query message includes, for example, the domain name in the DNS query message. The session management function element sends information indicating the terminal device's location to the edge application server discovery function element. The edge application server discovery function element adds the information indicating the terminal device's location to the DNS query message and sends the DNS query message with the added information indicating the terminal device's location to a DNS server. Based on the information indicating the terminal device's location, the DNS server determines the terminal device's current location and sends a DNS response message to the edge application server discovery function element. The DNS response message carries the address of an edge application server close to the terminal device, such as an EAS IP address. The edge application server discovery function element sends the DNS response message to the terminal device.

[0182] In addition, in the roaming scenario, the "edge application server discovery function network element" mentioned in the edge application server discovery process described in Figure 7 is the "visited domain edge application server discovery function network element," and the "session management function network element" is the "visited domain session management function network element." In the non-roaming scenario, where both a session management network element and an intermediate session management network element are included, the "edge application server discovery function network element" mentioned in the edge application server discovery process described in Figure 7 is the "intermediate edge application server discovery function network element," and the "session management function network element" is the "intermediate session management function network element." In the non-roaming scenario, where both a session management network element and a local session management network element are included, the "edge application server discovery function network element" mentioned in the edge application server discovery process described in Figure 7 is the "local edge application server discovery function network element," and the "session management function network element" is the "local session management function network element."

[0183] In addition, after the terminal device obtains the address of the edge application server through the edge application server discovery process, the terminal device can also store the correspondence between the domain name carried in the DNS query message and the address of the edge application server carried in the DNS response message. When the terminal device subsequently accesses the domain name, it can no longer initiate a DNS query, but instead directly send a data packet to the edge application server corresponding to the address corresponding to the domain name based on the cached correspondence between the domain name and the address of the edge application server.

[0184] For example, a terminal device initiates a DNS query for FQDN#1. Through the edge application server discovery process, the terminal device receives EAS IP address#1. The terminal device stores the correspondence between FQDN#1 and EAS IP address#1. When the terminal device subsequently accesses FQDN#1, it no longer initiates a DNS query. Instead, it sends a data packet directly to the edge application server corresponding to EAS IP address#1 based on the cached correspondence between FQDN#1 and EAS IP address#1.

[0185] 3. Edge application server rediscovery (EAS rediscovery or EAS relocation)

[0186] The edge application server rediscovery process is triggered after the edge application server discovery process is completed. Through the edge application server discovery process, the terminal device can obtain the address of the edge application server, so that the terminal device can access the edge application server. When the edge application server accessed by the terminal device is no longer suitable, the edge application server rediscovery process can be triggered so that the terminal device obtains the address of a new edge application server. Among them, the terminal device rediscovers the edge application server, which can also be understood as: the terminal device rediscovers the edge application server. The terminal device rediscovers the edge application server, which can include: the terminal device re-initiates a DNS query. Exemplarily, when the load of the edge application server is too high, the application function network element can trigger the edge application server rediscovery.

[0187] Before re-executing the edge application server discovery process, the terminal device also clears the locally stored DNS cache. Among them, the DNS cache stored locally on the terminal device includes: the correspondence between the domain name stored by the terminal device and the address of the edge application server. It is understandable that after the terminal device obtains the address of the edge application server through the edge application server discovery process, the terminal device also stores the correspondence between the domain name and the address of the edge application server. If the terminal device wants to access the domain name again later, the terminal device directly sends a data packet to the corresponding edge application server based on this cached correspondence. Therefore, if you want the terminal device to access other edge application servers for a certain domain name, the terminal device needs to delete the DNS cache corresponding to the domain name, that is, the terminal device needs to delete the correspondence between the domain name and the address of the edge application server, so that the terminal device will re-initiate a DNS query when it wants to access the domain name again, thereby re-executing the edge application server discovery process to discover the address of a new edge application server for the terminal device.

[0188] For example, the terminal device initiates a DNS query for FQDN#1. Through the edge application server discovery process, the terminal device receives EAS IP address #1. The terminal device stores the correspondence between FQDN#1 and EAS IP address #1. When the load of the edge application server corresponding to EAS IP address #1 is too high, the application function network element can trigger the edge application server rediscovery process. The terminal device deletes the correspondence between FQDN#1 and EAS IP address #1. When the terminal device wants to access FQDN#1 later, it initiates a DNS query again to re-execute the edge application server discovery process and obtain the address of the edge application server.

[0189] 4. EAS deployment information (EDI)

[0190] Edge application server deployment information can be used to reflect the deployment of the network at the edge. The edge application server deployment information may include one or more of the following parameters: AF ID, data network name (DNN), single network slice selection assistance information (S-NSSAI), external group identifier (external group identifier) / internal group identifier (internal group identifier), service ID (application ID, APP ID), one or more FQDNs, one or more data network access identifiers (DNAI), DNS server information (DNS server information), EAS IP address range information (EAS IP address range information), N6 traffic routing information (N6 traffic routing information). Among them, EAS IP address range information, DNS server information, and FQDN are deployed by the application service provider. DNAI, DNN, and S-NSSAI are the network (for example, 5G core network) identifiers for edge services. For a description of the parameters that may be included in the edge application server deployment information, please refer to Table 1.

[0191] Table 1

[0192] The edge application server deployment information is also used to reflect the correspondence between the parameters included. For example, the edge application server deployment information can be used to reflect the correspondence between the DNAI and one or more of the following: FQDN, EAS IP address range, and DNS server information. It is understandable that based on the edge application server deployment information, one or more of the following: FQDN, EAS IP address range, and DNS server information corresponding to each DNAI in the edge application server deployment information can be determined; if the FQDN or EAS IP address of a service is within the above range, it means that the service is deployed at the local edge.

[0193] In addition, the edge application server deployment information may be stored in a unified data repository (UDR), and the first network element or the second network element may obtain the edge application server deployment information from the UDR. For example, the first network element may provide a DNN and / or S-NSSAI to the UDR, thereby obtaining the edge application server deployment information related to the DNN and / or S-NSSAI.

[0194] In an embodiment of the present application, the first network element and the second network element may each configure edge application server deployment information corresponding to their service scopes. Exemplarily, when the service scope of the first network element does not intersect with the service scope of the second network element, the first network element may not configure edge application server deployment information corresponding to the service scope of the second network element. Exemplarily, when the service scope of the second network element is a subset of the service scope of the first network element, the edge application server deployment information configured by the second network element may be more accurate than the edge application server deployment information configured by the first network element. For example, the service scope of the first network element is city #1, and the service scope of the second network element is street #1 in city #1. Then, the first network element configures the edge application server deployment information corresponding to city #1, and the second network element configures the edge application server deployment information corresponding to street #1 in city #1.

[0195] In addition, when the first network element belongs to a home public land mobile network and the second network element belongs to a visited public land mobile network, the edge application server deployment information configured on the first network element may also be referred to as home domain edge application server deployment information (HPLMN EDI), and the edge application server deployment information configured on the second network element may also be referred to as visited domain edge application server deployment information (VPLMN EDI). When the second network element is a local network element, the edge application server deployment information configured on the second network element may also be referred to as local edge application server deployment information (local EDI, L-EDI).

[0196] The following describes an embodiment of the present application in detail with reference to the accompanying drawings. The embodiment of the present application uses a first network element, a second network element, a terminal device, and an application function network element as examples of the execution entities to illustrate the corresponding method, but the present application does not limit the execution entities of the method. For example, the network element / device in the method may also be a chip, a chip system, or a processor that supports the network element / device to implement the corresponding method, or a logical module or software that can implement all or part of the functions of the network element / device.

[0197] Please refer to FIG8 , which is a flow chart of a communication method 100 provided in an embodiment of the present application. The communication method 100 includes the following steps.

[0198] S101: An application function network element sends first information and a first service identifier to a first network element, where the first information is used to instruct server rediscovery. Correspondingly, the first network element receives the first information and the first service identifier from the application function network element.

[0199] In an optional implementation, in an embodiment of the present application, the server may be an edge application server. In this case, for example, the first information for instructing server rediscovery may be: "The first information for instructing edge application server rediscovery." "Server" hereinbelow may be replaced with "edge application server" and will not be further described.

[0200] It is understandable that step S101 can be performed after the edge application server discovery process is completed. After the edge application server discovery process is completed, the application function network element sends a first message to the first network element to instruct the edge application server to rediscover, which is conducive to triggering the edge application server rediscovery process. For a detailed description of the edge application server discovery process and the edge application server rediscovery process, please refer to the relevant description above and will not be repeated here.

[0201] In an optional manner, the first information is used to instruct the server to rediscover, which may be replaced by: the first information is used to trigger the server to rediscover. Optionally, the first information may be an "EAS relocation indication".

[0202] In an optional manner, the first service identifier can also be understood as a service identifier affected by server rediscovery. In addition, the service identifier can be represented by an APP ID, for example. Exemplarily, the first service identifier can be one or more APP IDs.

[0203] In an optional manner, the first information and the first service identifier are carried in an application function request (AF request) message sent by an application function network element.

[0204] In an optional manner, the application function network element sends the first information and the first service identifier to the first network element, which may be: the application function network element sends the first information and the first service identifier to the first network element through the intermediate network element. Exemplarily, the intermediate network element may directly forward the first information and the first service identifier from the application function network element to the first network element. Alternatively, the intermediate network element generates a new message based on the first information and the first service identifier received from the application function network element, and sends the message to the first network element. Optionally, the intermediate network element may also modify the form of the first information and / or the first service identifier, and the intermediate network element sends the modified first information and / or the modified first service identifier to the first network element.

[0205] Optionally, the intermediate network element may be a policy control function (PCF) network element, which receives the first information and the first service identifier from the application function network element, and creates a policy and charging control rule (PCC rule) based on the received first information and the first service identifier. The policy control function network element sends the policy and charging control rule to the first network element, where the policy and charging control rule includes ninth information and the first service identifier, and the ninth information is determined based on the first information. The ninth information may be the same as or different from the first information, but both the ninth information and the first information are used to instruct the server to rediscover.

[0206] For example, the first information is "indication for EAS relocation". The ninth information is the same as the first information. Alternatively, the ninth information is different from the first information and may be "EAS rediscovery indication" or "Indication of EAS rediscovery".

[0207] Optionally, the intermediate network element may be a policy control function network element and a network exposure function (NEF) network element. The application function network element sends the first information and the first service identifier to the first network element, including: the application function network element sends the first information and the first service identifier to the first network element through the network exposure function network element and the policy control function network element. This method can be applied to a scenario where the first network element is a session management function network element.

[0208] Exemplarily, an application function network element sends first information and a first service identifier to a first network element, including: the application function network element sends an application function request message to a network open function network element, the application function request message includes application function traffic influence request information (AF traffic influence request information), and the application function traffic influence request information includes the first information and the first service identifier; accordingly, the network open function network element receives the application function request from the application function network element. The network open function network element sends application function traffic influence request information to a policy control function network element; accordingly, the policy control function network element receives the application function traffic influence request information from the network open function network element. The policy control function network element generates a policy and charging control (PCC) rule based on the application function traffic influence request information and sends the PCC rule to the first network element; accordingly, the first network element receives the PCC rule from the policy control function network element. The application function traffic influence request information is expressed in the PCC rule as: application function influence on traffic routing enforcement control.

[0209] Optionally, the network open function network element sends the application function traffic impact request information to the policy control function network element. This may be: the network open function network element directly sends the application function traffic impact request information to the policy control function network element. Alternatively, the network open function network element stores the application function traffic impact request information in a unified data repository, and the policy control function network element then subscribes to the application function traffic impact request information from the unified data repository.

[0210] Optionally, the first service identifier may be used as a part of a "service data flow template" in the PCC rule.

[0211] In an optional implementation, the application function network element sends the first information and the first service identifier to the first network element, which can be replaced by: the application function network element sends the first service identifier to the first network element. It is understandable that the application function network element may not send the first information to the first network element. In this case, the application function network element can instruct the server to rediscover through the first service identifier.

[0212] S102: The first network element sends a first service identifier to the second network element. Correspondingly, the second network element receives the first service identifier from the first network element.

[0213] Step S102 is explained below, as described in the following optional implementations 1.1 to 1.4.

[0214] Implementation method 1.1, the first network element sends the first service identifier to the second network element, including: the first network element sends the first service identifier to the second network element when the first condition is met; the first condition includes: the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier.

[0215] In the embodiments of the present application, the server deployment information of the first network element can also be understood as server deployment information stored by the first network element, or can also be understood as server deployment information configured by the first network element. Furthermore, the server deployment information of the first network element can be server deployment information corresponding to the service scope of the first network element. The server deployment information of the second network element described below is similar and will not be further described.

[0216] In an embodiment of the present application, the domain name and address corresponding to the first business identifier are: the domain name and address of the server corresponding to the first business identifier. Among them, the server corresponding to the first business identifier can also be understood as: a server that provides services for the business corresponding to the first business identifier. The domain name can be, for example, an FQDN, and the address can be, for example, an EAS IP address. In addition, the domain name or address corresponding to the first business identifier can also be understood as: the impact field corresponding to the first business identifier. The domain name or address corresponding to the first business identifier can be sent to the terminal device as an impact field.

[0217] It is understandable that the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier, indicating that the first network element cannot obtain the domain name and address corresponding to the first service identifier based on the server deployment information of the first network element. Therefore, the first network element sending the first service identifier to the second network element facilitates the first network element to obtain the domain name and address corresponding to the first service identifier from the second network element.

[0218] For example, the server deployment information of the first network element includes service identifier #1, service identifier #2, domain name #1, and domain name #2, where service identifier #1 corresponds to domain name #1, and service identifier #2 corresponds to domain name #2. The first service identifier received by the first network element is service identifier #3. Therefore, the server deployment information of the first network element does not include service identifier #3. Based on the server deployment information of the first network element, the first network element cannot determine the domain name or address corresponding to service identifier #3. In other words, the server deployment information of the first network element does not include the domain name or address corresponding to service identifier #3. Therefore, the first network element sends service identifier #3 to the second network element.

[0219] Optionally, when the first condition is met, the first network element sends the first service identifier to the second network element. This may be: the first network element determines whether the first condition is met; if the first network element determines that the first condition is met, the first service identifier is sent to the second network element.

[0220] Optionally, the first network element sends the first service identifier to the second network element when the first condition is met. This can also be replaced by: the first network element sends the first service identifier to the second network element when the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier. In this manner, the first network element may not perform the operation of determining whether the first condition is met.

[0221] Implementation method 1.2, the method also includes: the application function network element sends the data network access identifier corresponding to the first information to the first network element; accordingly, the first network element receives the data network access identifier corresponding to the first information from the application function network element. The first network element sends the first service identifier to the second network element, including: the first network element sends the first service identifier to the second network element when the second condition is met; the second condition includes: the server deployment information of the first network element does not include the data network access identifier corresponding to the first information. Optionally, the sending path of the data network access identifier corresponding to the first information is the same as that of the first information. The data network access identifier corresponding to the first information can, for example, be carried by the potential locations of applications field; it can also be understood that: the data network access identifier corresponding to the first information can, for example, be included in the potential locations of applications field.

[0222] In this embodiment of the present application, the data network access identifier corresponding to the first information can also be understood as a data network access identifier affected by server rediscovery. A corresponding relationship exists between the data network access identifier corresponding to the first information and the first service identifier. This correspondence can be understood as indicating that the data network corresponding to the data network access identifier provides services for the service corresponding to the first service identifier. This will not be further described below.

[0223] It is understandable that the server deployment information of the first network element does not include the data network access identifier corresponding to the first information, indicating that the first network element does not support the data network access identifier corresponding to the first information. Therefore, if the server deployment information of the first network element does not include the data network access identifier corresponding to the first information, the first network element cannot obtain the domain name and address corresponding to the first service identifier based on the server deployment information of the first network element. Therefore, the first network element sends the first service identifier to the second network element, which facilitates the first network element to obtain the domain name and address corresponding to the first service identifier from the second network element.

[0224] In addition, in the embodiments of the present application, "data network access identifiers supported by a network element" can also be understood as data network access identifiers that the network element can serve. "Data network access identifiers not supported by a network element" can also be understood as data network access identifiers that the network element cannot serve. For example, "network element #1 supports data network access identifier #1" can be understood as "network element #1 can serve data network access identifier #1." For another example, "network element #1 does not support data network access identifier #1" can be understood as "network element #1 cannot serve data network access identifier #1." This will not be further described below.

[0225] Optionally, when the second condition is met, the first network element sends the first service identifier to the second network element. This may be: the first network element determines whether the second condition is met; if the first network element determines that the second condition is met, the first service identifier is sent to the second network element.

[0226] Optionally, the first network element sends the first service identifier to the second network element when the second condition is met. This can also be replaced by: the first network element sends the first service identifier to the second network element when the server deployment information of the first network element does not include a data network access identifier. In this manner, the first network element may not perform the operation of determining whether the second condition is met.

[0227] In implementation 1.3, a first network element belongs to a home public land mobile network of a terminal device, and a second network element belongs to a visited public land mobile network of the terminal device. The first network element sends a first service identifier to the second network element, including: the first network element sends the first service identifier to the second network element if a third condition is met; the third condition includes: the first network element does not store server deployment information of the visited public land mobile network.

[0228] The terminal device is a terminal device that executes the service corresponding to the first service identifier, and the terminal device accesses the service corresponding to the first service identifier through a first session. It is understandable that in a roaming scenario, the terminal device's serving public land mobile network is a visited public land mobile network, and the first service identifier represents server deployment information for the visited public land mobile network. Therefore, if the first network element does not store the server deployment information for the visited public land mobile network, the first network element cannot obtain the domain name and address corresponding to the first service identifier based on the stored server deployment information. Therefore, the first network element sends the first service identifier to the second network element, which facilitates the first network element obtaining the domain name and address corresponding to the first service identifier from the second network element.

[0229] Optionally, when the third condition is met, the first network element sends the first service identifier to the second network element. This may be: the first network element determines whether the third condition is met; if the first network element determines that the third condition is met, the first service identifier is sent to the second network element.

[0230] Optionally, when the third condition is satisfied, the first network element sends the first service identifier to the second network element. Alternatively, the first network element sends the first service identifier to the second network element when the first network element does not store the server deployment information of the visited public land mobile network. In this manner, the first network element may not determine whether the third condition is satisfied.

[0231] In implementation 1.4, the method further includes: the second network element sending third information to the first network element, the third information being used to indicate a data network access identifier supported by the second network element; accordingly, the first network element receives the third information from the second network element. The application function network element sends the data network access identifier corresponding to the first information to the first network element; accordingly, the first network element receives the data network access identifier corresponding to the first information from the application function network element. The first network element sends the first service identifier to the second network element, including: the first network element sending the first service identifier to the second network element if a fourth condition is met; the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

[0232] For example, the second network element sends third information #1 to the first network element. Third information #1 indicates that the second network element supports data network access identifiers #1, #2, and #3. The application function network element sends the first information, the first service identifier, and #2 to the first network element. Therefore, the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element, and the first network element can send the first service identifier to the second network element.

[0233] In addition, embodiments of the present application do not limit the form in which the third information indicates the data network access identifiers supported by the second network element. For example, the third information includes the data network access identifiers supported by the second network element. For another example, the third information is a list of interest data network access identifiers (interest DNAI list), and the interest data network access identifier list includes the data network access identifiers supported by the second network element.

[0234] Optionally, when the fourth condition is met, the first network element sends the first service identifier to the second network element. It can be that: the first network element determines whether the fourth condition is met; if the first network element determines that the fourth condition is met, it sends the first service identifier to the second network element.

[0235] Optionally, the first network element sending the first service identifier to the second network element when the fourth condition is met may be replaced by: the first network element sending the first service identifier to the second network element when the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element. In this manner, the first network element may not perform the operation of determining whether the fourth condition is met.

[0236] In addition, in an optional implementation, any multiple implementations in implementation 1.1 to implementation 1.4 can be used in combination. Specifically, the first network element sends the first service identifier to the second network element, including: the first network element sends the first service identifier to the second network element when at least two of the first condition, the second condition, the third condition and the fourth condition are met.

[0237] S103: The second network element sends the domain name or address corresponding to the first service identifier to the first network element based on the stored server deployment information. Correspondingly, the first network element receives the domain name or address corresponding to the first service identifier from the second network element.

[0238] In an optional implementation, the second network element sends the domain name or address corresponding to the first service identifier to the first network element based on the stored server deployment information, including: the second network element determines the domain name or address corresponding to the first service identifier based on the stored server deployment information; the second network element sends the domain name or address corresponding to the first service identifier to the first network element.

[0239] For example, the server deployment information stored by the second network element includes: service identifier #1, service identifier #2, domain name #1, and domain name #2, where domain name #1 corresponds to service identifier #1, and domain name #2 corresponds to service identifier #2. The first service identifier received by the second network element from the first network element is service identifier #2. Based on the stored server deployment information, the second network element determines domain name #2 corresponding to service identifier #2 and sends domain name #2 to the first network element.

[0240] In an optional embodiment, in the case where the first service identifier corresponds to multiple addresses in the server deployment information stored by the second network element, the second network element sends the address corresponding to the first service identifier to the first network element based on the stored server deployment information, including: the second network element determines the multiple addresses corresponding to the first service identifier based on the stored server deployment information; the second network element can select an address from the multiple addresses corresponding to the first service identifier based on the session information of the terminal device; the second network element sends the selected address to the first network element. The terminal device is a terminal device that executes the service corresponding to the first service identifier. Optionally, the session information includes one or more of the following: the location of the terminal device, data diversion rules, and data packet detection results. In another optional embodiment, the second network element can also send all the multiple addresses corresponding to the first service identifier to the first network element. In this case, the first network element sends the multiple addresses corresponding to the first service identifier received from the second network element to the terminal device.

[0241] In an optional embodiment, the method further includes: the first network element sending fourth information to the second network element, the fourth information being used to request the domain name or address corresponding to the first service identifier; and the second network element correspondingly receiving the fourth information from the first network element. Optionally, the fourth information being used to request the domain name or address corresponding to the first service identifier may be replaced by the fourth information being used to request the second network element to provide the domain name or address corresponding to the first service identifier.

[0242] S104. The first network element sends a first message to the terminal device. The first message includes a domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear server information corresponding to the domain name or address corresponding to the first service identifier. In response, the terminal device receives second information from the first network element and the domain name or address corresponding to the first service identifier.

[0243] The second information may be, for example, an EAS rediscovery indication. The second message may be a "PDU Session Modification Command," or a "network attached storage message (NAS message) non-access stratum message," or a "procedure control object (PCO)."

[0244] In an optional embodiment, instructing the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier may include instructing the terminal device to clear cached server information, where the domain name or address corresponding to the first service identifier indicates the server information to be cleared. Furthermore, "clear" may be replaced with "delete," "refresh," or the like.

[0245] In an optional implementation manner, the second information is carried by a protocol configuration option (PCO) field, and / or the domain name or address corresponding to the first service identifier is carried by the PCO field.

[0246] In an optional implementation manner, the server information corresponding to the domain name or address corresponding to the first service identifier includes: a correspondence between the domain name corresponding to the first service identifier and the address corresponding to the first service identifier.

[0247] It is understandable that, through the server discovery process, after the terminal device obtains an address for the domain name, the terminal device can access the server corresponding to the address to execute the service corresponding to the first service identifier, and the terminal device also stores the correspondence between the domain name and the address. Thereafter, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device, which helps the terminal device clear the correspondence between the domain name corresponding to the first service identifier and the address corresponding to the first service identifier, thereby facilitating the terminal device to rediscover the server for the domain name corresponding to the first service identifier.

[0248] In an optional embodiment, when the domain name or address corresponding to the first service identifier received by the first network element from the second network element is empty, or when the first network element receives information from the second network element indicating that the domain name or address corresponding to the first service identifier cannot be obtained, the second information sent by the first network element to the terminal device is used to instruct the terminal device to clear server information related to a first session used by the terminal device to access the service corresponding to the first service identifier. Furthermore, in this case, the domain name or address corresponding to the first service identifier sent by the first network element to the terminal device is empty, or the first network element does not send the domain name or address corresponding to the first service identifier to the terminal device.

[0249] Exemplarily, if the second network element cannot obtain / determine the domain name or address corresponding to the first service identifier, the second network element sends the domain name or address corresponding to the first service identifier to the first network element, and the domain name or address is empty. The first network element sends second information to the terminal device, and the second information is used to instruct the terminal device to clear server information related to the first session. In addition, the first network element sends the domain name or address corresponding to the first service identifier to the terminal device, and the domain name or address is empty, or the first network element does not send the domain name or address corresponding to the first service identifier to the terminal device.

[0250] Exemplarily, if the second network element cannot obtain / determine the domain name or address corresponding to the first service identifier, the second network element sends information to the first network element indicating that the domain name or address corresponding to the first service identifier cannot be obtained. The second network element may not send the domain name or address corresponding to the first service identifier to the first network element (the domain name or address is empty). The first network element sends second information to the terminal device, and the second information is used to instruct the terminal device to clear server information related to the first session. Furthermore, the first network element sends the domain name or address corresponding to the first service identifier to the terminal device, and the domain name or address is empty, or the first network element does not send the domain name or address corresponding to the first service identifier to the terminal device. In an optional embodiment, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device, which can be replaced by the first network element sending the domain name or address corresponding to the first service identifier to the terminal device. It is understandable that the first network element may not send the second information to the terminal device. In this case, the first network element can use the domain name or address corresponding to the first service identifier to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

[0251] In an optional embodiment, the method further includes: the terminal device clearing the server information corresponding to the domain name or address corresponding to the first service identifier. It is understandable that the terminal device clears the cached server information corresponding to the domain name or address corresponding to the first service identifier.

[0252] For example, consider a domain name that is an FQDN and an address that is an EAS IP address. A terminal device initiates a DNS query for FQDN#1. Through the server discovery process, the terminal device obtains EAS IP address#1. The terminal device accesses EAS IP address#1 to execute the service corresponding to the first service identifier. The terminal device also stores the correspondence between FQDN#1 and EAS IP address#1. Subsequently, the application function network element sends the first information and the first service identifier to the first network element.

[0253] The first network element receives FQDN#1 corresponding to the first service identifier from the second network element. The first network element sends second information and FQDN#1 to the terminal device. The second information is used to instruct the terminal device to clear the server information corresponding to FQDN#1. The terminal device clears the server information corresponding to FQDN#1. The server information corresponding to FQDN#1 includes the correspondence between FQDN#1 and EAS IP address#1.

[0254] Alternatively, the first network element receives EAS IP address #1 corresponding to the first service identifier from the second network element. The first network element sends second information and EAS IP address #1 to the terminal device, where the second information instructs the terminal device to clear the server information corresponding to EAS IP address #1. The terminal device clears the server information corresponding to EAS IP address #1. The server information corresponding to EAS IP address #1 includes a correspondence between FQDN #1 and EAS IP address #1.

[0255] Optionally, after the terminal device clears the server information corresponding to the domain name or address corresponding to the first service identifier, the terminal device performs server rediscovery. The server rediscovery performed by the terminal device may be performed when the terminal device wants to access the domain name corresponding to the first service identifier after clearing the server information corresponding to the domain name or address corresponding to the first service identifier.

[0256] For example, the domain name corresponding to the first service identifier is domain name #1, and the address corresponding to the first service identifier is address #1. The terminal device receives the second information from the first network element and domain name #1 or address #1, and the terminal device clears the server information corresponding to domain name #1 or address #1. Thereafter, when the terminal device attempts to access domain name #1, it rediscovers the server for domain name #1.

[0257] In summary, in communication method 100, a first network element receives first information and a first service identifier from an application function network element, where the first information is used to instruct an edge application server to rediscover the service. The first network element sends the first service identifier to a second network element. The second network element sends the domain name or address corresponding to the first service identifier to the first network element. The first network element sends second information and the domain name or address corresponding to the first service identifier to a terminal device, where the second information is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0258] It can be seen that in this method, the first network element obtains the domain name or address corresponding to the first service identifier from the second network element, and then the first network element sends the second information and the domain name or address corresponding to the first service identifier, the first message to the terminal device, so that the terminal device clears the edge application server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device obtains the address of the new edge application server, and then the new edge application server provides services to the terminal device to improve the service quality of the terminal device.

[0259] Please refer to FIG. 9 , which is a flow chart of a communication method 200 provided in an embodiment of the present application. The communication method 200 includes the following steps.

[0260] S201: An edge application server discovery function network element sends a domain name or address to a second network element. Correspondingly, the second network element receives the domain name or address from the edge application server discovery function network element.

[0261] Step S201 may be performed during the edge application server discovery process, or may be performed after the edge application server discovery process is completed, and there is no limitation on this.

[0262] In an optional embodiment, the method further includes: the terminal device sending a DNS query message to the edge application server discovery function network element, the DNS query message including the domain name; and the edge application server discovery function network element correspondingly receiving the DNS query message from the terminal device. This embodiment enables the edge application server discovery function network element to obtain the domain name, thereby enabling the edge application server discovery function network element to send the domain name to the second network element. Furthermore, this embodiment can be executed during the edge application server discovery process.

[0263] For example, consider a domain name that is an FQDN. During the edge application server discovery process, the terminal device sends a DNS query message to the edge application server discovery function network element. The DNS query message includes FQDN#1. Therefore, the edge application server discovery function network element receives FQDN#1 and can then send FQDN#1 to the second network element.

[0264] In an optional embodiment, the method further includes: the terminal device sends a DNS query message to the edge application server discovery function network element, and the DNS query message includes a domain name; accordingly, the edge application server discovery function network element receives the DNS query message from the terminal device. The edge application server discovery function network element sends a DNS query message to the DNS server; accordingly, the DNS server receives the DNS query message from the application server discovery function network element. The DNS server sends a DNS response message to the edge application server discovery function network element, and the DNS response message includes an address; accordingly, the edge application server discovery function network element receives the DNS response message from the DNS server. It can be seen that through this embodiment, the edge application server discovery function network element can obtain the domain name and / or address, so that the edge application server discovery function network element can send the domain name or address to the second network element. In addition, this embodiment can be executed in the edge application server discovery process.

[0265] For example, let's take a domain name of FQDN and an address of EAS IP address as an example. In the edge application server discovery process, the terminal device sends a DNS query message to the edge application server discovery function network element, and the DNS query message includes FQDN#1. The edge application server discovery function network element sends a DNS query message to the DNS server. The DNS server sends a DNS response message to the edge application server discovery function network element, and the DNS response message includes EAS IP address#1. It can be seen that the edge application server discovery function network element receives FQDN#1 and EAS IP address#1, so the edge application server discovery function network element can send FQDN#1 or EAS IP address#1 to the second network element.

[0266] S202: The second network element sends fifth information to the first network element based on the domain name or address, where the fifth information indicates a correspondence between the first service identifier and the domain name, or indicates a correspondence between the first service identifier and the address. Accordingly, the first network element receives the fifth information from the second network element.

[0267] In an optional manner, the second network element sends the fifth information to the first network element based on the domain name or address, including: the second network element sends the fifth information to the first network element based on the domain name or address and stored server deployment information.

[0268] In an optional embodiment, the second network element sends fifth information to the first network element based on the domain name or address and the stored edge application server deployment information, including: the second network element determines the first service identifier corresponding to the domain name or address based on the stored edge application server deployment information; the second network element sends the fifth information to the first network element.

[0269] For example, taking the domain name as an FQDN, the second network element receives FQDN#1 from the edge application server discovery function network element, determines the service identifier #1 (service identifier #1 is the first service identifier) ​​corresponding to FQDN#1 based on the stored edge application server deployment information, and sends fifth information to the first network element, where the fifth information is used to indicate the correspondence between service identifier #1 and FQDN#1.

[0270] For another example, taking the address as an EAS IP address, the second network element receives EAS IP address #1 from the edge application server discovery function network element, determines the service identifier #1 (service identifier #1 is the first service identifier) ​​corresponding to the EAS IP address #1 based on the stored edge application server deployment information, and sends fifth information to the first network element, where the fifth information is used to indicate the correspondence between the service identifier #1 and the EAS IP address.

[0271] In addition, the embodiments of the present application do not limit the manner in which the fifth information indicates the correspondence between the first service identifier and the domain name, or the manner in which the fifth information indicates the correspondence between the first service identifier and the address. For example, if the fifth information is used to indicate the correspondence between the first service identifier and the domain name, it can be expressed as follows: the fifth information includes the first service identifier and the domain name. For another example, if the fifth information is used to indicate the correspondence between the first service identifier and the address, it can be expressed as follows: the fifth information includes the first service identifier and the address.

[0272] In addition, step S202 may also be described in the following optional implementation 2.1 and implementation 2.2.

[0273] Implementation method 2.1, the second network element sends the fifth information to the first network element based on the domain name or address, including: the second network element sends the fifth information to the first network element based on the domain name or address when the fifth condition is met; the fifth condition includes: the second network element has stored the identifier of the access and mobility management function network element.

[0274] Optionally, the fifth condition includes: the second network element has stored an identifier of the access and mobility management function network element and an identifier of the first network element. The identifier of the access and mobility management function network element is, for example, an ID of the access and mobility management function network element, and the identifier of the first network element is, for example, an ID of the first network element.

[0275] Optionally, when the fifth condition is met, the second network element sends the fifth information to the first network element based on the domain name or address. It can be that: the second network element determines whether the fifth condition is met; if the second network element determines that the fifth condition is met, it sends the fifth information to the first network element based on the domain name or address.

[0276] Optionally, when the fifth condition is met, the second network element sends the fifth information to the first network element based on the domain name or address. Alternatively, the second network element may send the fifth information to the first network element based on the domain name or address when the identifier of the access and mobility management function network element is stored. In this manner, the second network element may not determine whether the fifth condition is met.

[0277] Implementation method 2.2, the second network element sends the fifth information to the first network element based on the domain name or address, including: the second network element sends the fifth information to the first network element based on the domain name or address when the sixth condition is met; the sixth condition includes: the second network element has not sent the correspondence between the first service identifier and the domain name to the first network element, and the second network element has not sent the correspondence between the first service identifier and the address to the first network element.

[0278] It is understandable that if the second network element has not sent the correspondence between the first service identifier and the domain name and the correspondence between the first service identifier and the address to the first network element, the second network element may send the fifth information to the first network element. If the second network element has already sent the correspondence between the first service identifier and the domain name and the correspondence between the first service identifier and the address to the first network element, the second network element may not send the fifth information to the first network element, thereby reducing signaling overhead.

[0279] Optionally, when the sixth condition is met, the second network element sends the fifth information to the first network element based on the domain name or address. It can be that: the second network element determines whether the sixth condition is met; if the second network element determines that the sixth condition is met, it sends the fifth information to the first network element based on the domain name or address.

[0280] Optionally, when the sixth condition is met, the second network element sends the fifth information to the first network element based on the domain name or address. This can also be replaced by: when the second network element has not sent the correspondence between the first service identifier and the domain name and the correspondence between the first service identifier and the address to the first network element, the second network element sends the fifth information to the first network element based on the domain name or address. In this manner, the second network element may not perform the operation of determining whether the sixth condition is met.

[0281] In addition, in one embodiment, implementation 2.1 and implementation 2.2 can be used in combination. Specifically, the second network element sends the fifth information to the first network element based on the stored edge application server deployment information, including: when the fifth condition and the sixth condition are met, the second network element sends the fifth information to the first network element based on the domain name or address.

[0282] In an optional implementation, the method further includes: the first network element storing, based on the fifth information, a correspondence between the first service identifier and the domain name, or storing a correspondence between the first service identifier and the address.

[0283] S203: The application function network element sends first information and a first service identifier to the first network element, where the first information is used to instruct the server to rediscover the service. Correspondingly, the first network element receives the first information and the first service identifier from the application function network element.

[0284] For the detailed description of step S203, please refer to the relevant description of step S101 in the communication method 100, which will not be repeated here.

[0285] S204: The first network element sends a first message to the terminal device based on the fifth information and the first service identifier. The first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier. In response, the terminal device receives the second information and the domain name or address corresponding to the first service identifier from the first network element.

[0286] For a detailed description of the first message, please refer to the relevant description in the communication method 100 and will not be repeated here.

[0287] In an optional embodiment, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: the first network element determines the domain name or address corresponding to the first service identifier based on the fifth information and the first service identifier; the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device.

[0288] In addition, step S204 may also be described in the following optional implementations 3.1 to 3.4.

[0289] Implementation 3.1, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: when a first condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier; the first condition includes: the edge application server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier. This implementation 3.1 is similar to implementation 1.1 in communication method 100. For details, please refer to the aforementioned relevant explanation of implementation 1.1 and will not be repeated here.

[0290] Optionally, when the first condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. It can be: the first network element determines whether the first condition is met; if the first network element determines that the first condition is met, the second information and the domain name or address corresponding to the first service identifier are sent to the terminal device based on the fifth information and the first service identifier.

[0291] Optionally, when the first condition is satisfied, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. This can also be replaced by: when the edge application server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. In this manner, the first network element may not perform the operation of determining whether the first condition is satisfied.

[0292] Implementation method 3.2, the method also includes: the first network element receives a data network access identifier corresponding to the first information from the application function network element. The first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: when the second condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier; the second condition includes: the edge application server deployment information of the first network element does not include the data network access identifier. This implementation method 3.2 is similar to implementation method 1.2 in the communication method 100, and you can also refer to the aforementioned explanation of implementation method 1.1 for details, which will not be repeated here.

[0293] Optionally, when the second condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. It can be: the first network element determines whether the second condition is met; if the first network element determines that the second condition is met, the second information and the domain name or address corresponding to the first service identifier are sent to the terminal device based on the fifth information and the first service identifier.

[0294] Optionally, when the second condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. This can also be replaced by: when the edge application server deployment information of the first network element does not include a data network access identifier, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. In this manner, the first network element may not perform the operation of determining whether the second condition is met.

[0295] In implementation 3.3, the first network element belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device. The first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier when a third condition is met; the third condition includes: the first network element does not store the edge application server deployment information of the visited public land mobile network. This implementation 3.3 is similar to implementation 1.3 in communication method 100. For details, please refer to the aforementioned explanation of implementation 1.3 and will not be repeated here.

[0296] Optionally, when the third condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. It can be: the first network element determines whether the third condition is met; if the first network element determines that the third condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier.

[0297] Optionally, when the third condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. This may also be replaced by: when the first network element does not store edge application server deployment information of the visited public land mobile network, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. In this manner, the first network element may not perform the operation of determining whether the third condition is met.

[0298] Implementation method 3.4, the method also includes: the first network element receives third information from the second network element, the third information is used to indicate the data network access identifier supported by the second network element; the first network element receives the data network access identifier corresponding to the first information from the application function network element. The first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier when the fourth condition is met; the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element. This implementation method 3.4 is similar to implementation method 1.4 in the communication method 100. For details, please refer to the aforementioned relevant explanation of implementation method 1.1 and will not be repeated here.

[0299] Optionally, when the fourth condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. It can be: the first network element determines whether the fourth condition is met; if the first network element determines that the fourth condition is met, the second information and the domain name or address corresponding to the first service identifier are sent to the terminal device based on the fifth information and the first service identifier.

[0300] Optionally, when the fourth condition is satisfied, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. This may also be replaced by: when the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. In this manner, the first network element may not perform the operation of determining whether the fourth condition is satisfied.

[0301] In addition, in an optional implementation, any multiple implementations in implementation 3.1 to implementation 3.4 can be used in combination. Specifically, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: when the first condition is met, and at least two of the second condition, the third condition and the fourth condition are met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier.

[0302] In an optional embodiment, the method further includes: the second network element sends multiple seventh information to the first network element, and the multiple seventh information includes the fifth information. Each seventh information is used to indicate the correspondence between the service identifier and the domain name, or to indicate the correspondence between the service identifier and the address. The first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: the first network element determines the domain name or address corresponding to the first service identifier from the multiple seventh information based on the first service identifier; the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device.

[0303] It is understandable that each of the plurality of seventh information is used to indicate the correspondence between the service identifier and the domain name. Alternatively, each of the plurality of seventh information is used to indicate the correspondence between the service identifier and the address. Alternatively, some of the plurality of seventh information is used to indicate the correspondence between the service identifier and the domain name, and the remaining seventh information is used to indicate the correspondence between the service identifier and the address.

[0304] In addition, the embodiment of the present application does not limit the manner in which the second network element sends multiple seventh information. For example, the second network element can send multiple seventh information at the same time, or the second network element can also execute the operation of sending the seventh information after determining a seventh information each time.

[0305] Optionally, the method further includes: the first network element storing a correspondence between the service identifier and the domain name indicated by each seventh information in the plurality of seventh information, or a correspondence between the indicated service identifier and the address.

[0306] For example, the domain name is FQDN and the service identifier is APP ID.

[0307] In the edge application server discovery process for FQDN#1, the second network element receives FQDN#1 from the edge application server discovery function network element. The second network element may determine APP ID#1 corresponding to FQDN#1 based on the stored edge application server deployment information and send seventh information #1 to the first network element. The seventh information #1 is used to indicate the correspondence between FQDN#1 and APP ID#1.

[0308] In the edge application server discovery process for FQDN#2, the second network element receives FQDN#2 from the edge application server discovery function network element. The second network element determines the APP ID#2 corresponding to FQDN#2 based on the stored edge application server deployment information and sends the seventh information #2 to the first network element. The seventh information #2 is used to indicate the correspondence between FQDN#2 and APP ID#2.

[0309] In the edge application server discovery process for FQDN#1, the second network element receives FQDN#3 from the edge application server discovery function network element. The second network element determines the APP ID#3 corresponding to FQDN#3 based on the stored edge application server deployment information and sends the seventh information #3 to the first network element. The seventh information #3 is used to indicate the correspondence between FQDN#3 and APP ID#3.

[0310] The first network element receives the first information and APP ID #2 (APP ID #2 is a first service identifier) ​​from the application function network element. Based on APP ID #2, the first network element determines FQDN #2 corresponding to APP ID #2 from the seventh information #1, the seventh information #2, and the seventh information #3. The first network element sends the second information and FQDN #2 to the terminal device.

[0311] In an optional embodiment, the method further includes: the terminal device clearing the server information corresponding to the domain name or address corresponding to the first service identifier. Optionally, after the terminal device clears the server information corresponding to the domain name or address corresponding to the first service identifier, the terminal device performs server rediscovery. A detailed description of this embodiment can be found in the relevant description of communication method 100 and is not repeated here.

[0312] For the specific description of the first network element sending the first message to the terminal device, please refer to the relevant description in the communication method 100, which will not be repeated here.

[0313] To summarize, in the communication method 200, the second network element receives a domain name or address from the edge application server discovery function network element. Based on the stored edge application server deployment information, the second network element sends fifth information to the first network element, where the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address. The first network element receives the first information and the first service identifier from the application function network element, where the first information is used to instruct the edge application server to rediscover. Based on the fifth information and the first service identifier, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device, where the second information is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0314] It can be seen that this method is beneficial for the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device can obtain the address of a new edge application server, and then the new edge application server provides services to the terminal device to improve the service quality of the terminal device.

[0315] Please refer to FIG. 10 , which is a flow chart of a communication method 300 provided in an embodiment of the present application. The communication method 300 includes the following steps.

[0316] S301: An application function network element sends first information and a first service identifier to a first network element, where the first information is used to instruct an edge application server to rediscover. Correspondingly, the first network element receives the first information and the first service identifier from the application function network element.

[0317] For a detailed description of step S301, please refer to the relevant description of step S101 in the communication method 100, which will not be repeated here.

[0318] S302: The first network element sends sixth information to the application function network element, where the sixth information is used to request the domain name or address corresponding to the first service identifier. Correspondingly, the application function network element receives the sixth information from the first network element.

[0319] In an optional implementation, the sixth information is used to request the domain name or address corresponding to the first service identifier, which can also be understood as: the sixth information is used to request the application function network element to provide the domain name or address corresponding to the first service identifier.

[0320] Step S302 is explained below, as described in the following optional implementations 4.1 to 4.4.

[0321] In embodiment 4.1, the first network element sends sixth information to the application function network element, including: the first network element sends the sixth information to the application function network element when a first condition is satisfied; the first condition includes: the edge application server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier. This embodiment 4.1 is similar to embodiment 1.1 of communication method 100. For details, please refer to the above description of embodiment 1.1 and will not be repeated here.

[0322] Optionally, when the first condition is met, the first network element sends the sixth information to the application function network element, which may be: the first network element determines whether the first condition is met; if the first network element determines that the first condition is met, the sixth information is sent to the application function network element.

[0323] Optionally, when the first condition is met, the first network element sends the sixth information to the application function network element. This can also be replaced by: when the edge application server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier, the first network element sends the sixth information to the application function network element. In this manner, the first network element may not perform the operation of determining whether the first condition is met.

[0324] In embodiment 4.2, the method further includes: the first network element receiving a data network access identifier corresponding to the first information from the application function network element. The first network element sending sixth information to the application function network element includes: the first network element sending the sixth information to the application function network element if a second condition is satisfied; the second condition includes: the edge application server deployment information of the first network element does not include the data network access identifier. This embodiment 4.2 is similar to embodiment 1.2 of communication method 100. For details, please refer to the aforementioned explanation of embodiment 1.1 and will not be repeated here.

[0325] Optionally, when the second condition is met, the first network element sends the sixth information to the application function network element, which can be: the first network element determines whether the second condition is met; if the first network element determines that the second condition is met, it sends the sixth information to the application function network element.

[0326] Optionally, the first network element sends the sixth information to the application function network element when the second condition is met. This can also be replaced by: the first network element sends the sixth information to the application function network element when the edge application server deployment information of the first network element does not include the data network access identifier. In this manner, the first network element may not perform the operation of determining whether the second condition is met.

[0327] In embodiment 4.3, the first network element belongs to a home public land mobile network, the second network element belongs to a visited public land mobile network, and the serving public land mobile network of the terminal device is the visited public land mobile network. The first network element sends sixth information to the application function network element, including: the first network element sends the sixth information to the application function network element when a third condition is met; the third condition includes: the first network element does not store edge application server deployment information of the visited public land mobile network. This embodiment 4.3 is similar to embodiment 1.3 of communication method 100. For details, please refer to the aforementioned description of embodiment 1.3 and will not be repeated here.

[0328] Optionally, when the third condition is met, the first network element sends the sixth information to the application function network element, which can be: the first network element determines whether the third condition is met; if the first network element determines that the third condition is met, it sends the sixth information to the application function network element.

[0329] Optionally, when the third condition is met, the first network element sends the sixth information to the application function network element. Alternatively, the first network element sends the sixth information to the application function network element when the first network element does not store the edge application server deployment information of the visited public land mobile network. In this manner, the first network element may not determine whether the third condition is met.

[0330] In embodiment 4.4, the method further includes: the first network element receives third information from the second network element, the third information being used to indicate a data network access identifier supported by the second network element; and the first network element receives a data network access identifier corresponding to the first information from the application function network element. The first network element sends sixth information to the application function network element, including: the first network element sends the sixth information to the application function network element when a fourth condition is met; the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element. This embodiment 4.4 is similar to embodiment 1.4 in communication method 100. For details, please refer to the aforementioned explanation of embodiment 1.1 and will not be repeated here.

[0331] Optionally, when the fourth condition is met, the first network element sends the sixth information to the application function network element, which can be: the first network element determines whether the fourth condition is met; if the first network element determines that the fourth condition is met, it sends the sixth information to the application function network element.

[0332] Optionally, the first network element sends the sixth information to the application function network element when the fourth condition is met. This can also be replaced by: the first network element sends the sixth information to the application function network element when the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element. In this manner, the first network element may not perform the operation of determining whether the fourth condition is met.

[0333] In addition, in an optional implementation, any multiple implementations in Implementation 4.1 to Implementation 4.4 can be used in combination. Specifically, the first network element sends the sixth information to the application function network element, including: the first network element sends the sixth information to the application function network element when at least two of the first condition, the second condition, the third condition and the fourth condition are met.

[0334] S303: The application function network element sends the domain name or address corresponding to the first service identifier to the first network element. Correspondingly, the first network element receives the domain name or address corresponding to the first service identifier from the application function network element.

[0335] In an optional embodiment, the method further includes: the first network element sends an eighth information to the application function network element, and the eighth information is used to request the application function network element to resend the application function request message. This embodiment can be applied to the case where the first information sent by the application function network element and the first service identifier are carried in the application function request message sent by the application function network element. In this case, the domain name or address corresponding to the first service identifier sent by the application function network element can be carried in the application function request message resent by the application function network element. In an optional manner, the sixth information sent by the first network element is carried in the eighth information sent by the first network element.

[0336] Exemplarily, the application function network element sends application function request message #1, which includes the first information and the first service identifier. The first network element sends the eighth information and the sixth information to the application function network element, or the first network element sends the eighth information (the eighth information includes the sixth information) to the application function network element, wherein the eighth information is used to request the application function network element to resend the application function request message, and the sixth information is used to request the domain name or address corresponding to the first service identifier. The application function network element sends application function request message #2, which includes the domain name or address corresponding to the first service identifier.

[0337] S304. The first network element sends a first message to the terminal device. The first message includes a domain name or address corresponding to the first service identifier. The first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0338] For a detailed description of the first message, please refer to the relevant description in the communication method 100 and will not be repeated here.

[0339] For the specific description of the first network element sending the first message to the terminal device, please refer to the relevant description in the communication method 100, which will not be repeated here.

[0340] In an optional embodiment, the method further includes: the terminal device clearing the edge application server information corresponding to the domain name or address corresponding to the first service identifier. Optionally, after the terminal device clears the edge application server information corresponding to the domain name or address corresponding to the first service identifier, the terminal device rediscovers the edge application server. A detailed description of this embodiment can be found in the relevant description of communication method 100 and is not repeated here.

[0341] In summary, in the communication method 300, the application function network element sends first information and a first service identifier to the first network element, where the first information is used to instruct the edge application server to rediscover. The first network element sends sixth information to the application function network element, where the sixth information is used to request the domain name or address corresponding to the first service identifier. The application function network element sends the domain name or address corresponding to the first service identifier to the first network element. The first network element sends second information and the domain name or address corresponding to the first service identifier to the terminal device, where the second information is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

[0342] It can be seen that this method is beneficial for the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first business identifier, thereby facilitating the terminal device to rediscover the edge application server to re-acquire the address of the edge application server, and then the edge application server corresponding to the re-acquired address provides services to the terminal device, that is, the rediscovered edge application server provides services to the terminal device.

[0343] This method can be applied to scenarios where the edge application server accessed by a terminal device is overloaded. In this scenario, this communication method helps the terminal device clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier, so that the terminal device can rediscover the edge application server, and the rediscovered edge application server can then provide services to the terminal device, thereby improving the service quality for the terminal device and improving communication performance.

[0344] Please refer to FIG. 11 , which is a flow chart of a communication method 400 provided in an embodiment of the present application. The communication method 400 includes the following steps.

[0345] S401: An application function network element sends first information and a first service identifier to a first network element, where the first information is used to instruct an edge application server to rediscover the application server. Correspondingly, the first network element receives the first information and the first service identifier from the application function network element.

[0346] For detailed description of S401, please refer to the relevant description in the communication method 100, which will not be repeated here.

[0347] S402. When the first network element cannot obtain the domain name or address corresponding to the first service identifier, the first network element sends second information to the terminal device, where the second information is used to instruct the terminal device to clear all edge application server information related to the first session, where the first session is used for the terminal device to access the service corresponding to the first service identifier.

[0348] For a detailed description of the second information, please refer to the relevant description in the communication method 100 and will not be repeated here.

[0349] In an optional manner, the situation where the first network element is unable to obtain the domain name or address corresponding to the first service identifier includes: the edge application server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier; or the first network element does not store the edge application server deployment information of the visited public land mobile network; or the edge application server deployment information of the first network element does not include the data network access identifier; or the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element; or the first network element is a home domain session management function network element and the second network element is a visited domain session management function network element; or the first network element is a session management function network element and the second network element is an intermediate session management function network element; or the first network element is a session management function network element and the second network element is used to assist the session management function network element in processing edge application server related information. For detailed description, please refer to the relevant description above and will not be repeated here.

[0350] In an optional manner, in the expression of instructing the terminal device to clear all edge application server information related to the first session, “clear” may also be replaced by “delete”, “refresh”, etc.

[0351] In an optional embodiment, the method further includes: the terminal device clearing the edge application server information corresponding to the domain name or address corresponding to the first service identifier. Optionally, after the terminal device clears the edge application server information corresponding to the domain name or address corresponding to the first service identifier, the terminal device rediscovers the edge application server. A detailed description of this embodiment can be found in the relevant description of communication method 100 and is not repeated here.

[0352] It can be seen that this method is beneficial to the edge application server information related to the terminal device and the first session, thereby facilitating the terminal device to rediscover the edge application server to re-acquire the address of the edge application server, and then the edge application server corresponding to the re-acquired address provides services to the terminal device, that is, the rediscovered edge application server provides services to the terminal device.

[0353] This method can be applied to a scenario where the edge application server accessed by a terminal device is overloaded. In this scenario, this communication method helps the terminal device clear the edge application server information related to the first session, so that the terminal device can rediscover the edge application server, and the rediscovered edge application server can then provide services to the terminal device, thereby improving the service quality for the terminal device and improving communication performance.

[0354] To implement the various functions of the methods provided in the embodiments of the present application, network elements / devices may include hardware structures and / or software modules, and the aforementioned functions may be implemented in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular one of the aforementioned functions is implemented in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the specific application and design constraints of the technical solution.

[0355] As shown in Figure 12, an embodiment of the present application provides a communication device 1200. The communication device 1200 can be a first network element or a second network element or an application function network element, or a component of the first network element (for example, an integrated circuit, a chip, etc.), or a component of the second network element (for example, an integrated circuit, a chip, etc.), or a component of the application function network element (for example, an integrated circuit, a chip, etc.). The communication device 1200 can also be other communication units for implementing the method in the method embodiment of the present application. The communication device 1200 may include a processing unit 1201. Optionally, the communication device 1200 may further include a communication unit 1202, and the processing unit 1201 is used to control the communication unit 1202 to send and receive data / signaling. The communication unit 1202 may also be referred to as a transceiver unit. Optionally, the communication unit 1202 may include a sending unit and a receiving unit. The sending unit may be used to send data / signaling, and the receiving unit may be used to receive data / signaling. Optionally, the communication device 1200 may further include a storage unit 1203 , which may be used to store information and / or data and / or instructions, etc. The storage unit 1203 may interact with the processing unit 1201 and may also interact with the communication unit 1202 .

[0356] In one possible design, for a case where the communication apparatus 1200 is used to implement the function of the first network element in the above method embodiment:

[0357] Communication unit 1202 is used to receive first information and a first service identifier from an application function network element, where the first information is used to instruct server rediscovery. Communication unit 1202 is also used to send the first service identifier to a second network element. Communication unit 1202 is also used to receive a domain name or address corresponding to the first service identifier from the second network element. Communication unit 1202 is also used to send a first message to a terminal device, where the first message includes a domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear server information corresponding to the domain name or address corresponding to the first service identifier.

[0358] In an optional embodiment, the communication unit 1202 sends the first service identifier to the second network element, specifically for: sending the first service identifier to the second network element when the first condition is met; the first condition includes: the server deployment information of the communication device 1200 does not include the domain name and address corresponding to the first service identifier.

[0359] In an optional embodiment, communication unit 1202 is further configured to receive a data network access identifier corresponding to the first information from the application function network element. Communication unit 1202 sends the first service identifier to the second network element, specifically configured to send the first service identifier to the second network element if a second condition is met, where the second condition includes: the server deployment information of communication device 1200 does not include the data network access identifier.

[0360] In an optional embodiment, the communication device 1200 belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device. The communication unit 1202 sends the first service identifier to the second network element, specifically configured to send the first service identifier to the second network element if a third condition is met, where the third condition includes: the communication device 1200 does not store server deployment information of the visited public land mobile network.

[0361] In an optional embodiment, the communication unit 1202 is further configured to receive third information from the second network element, the third information being used to indicate a data network access identifier supported by the second network element; and the communication unit 1202 is further configured to receive the data network access identifier corresponding to the first information from the application function network element. The communication unit 1202 sends the first service identifier to the second network element, specifically, when a fourth condition is met, sending the first service identifier to the second network element; the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

[0362] In an optional implementation, the communication unit 1202 is further configured to send fourth information to the second network element, where the fourth information is used to request a domain name or address corresponding to the first service identifier.

[0363] In an optional implementation, the communication device 1200 is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the communication device 1200 is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the communication device 1200 is a session management function network element, and the second network element is configured to assist the session management function network element in processing server-related information.

[0364] In another possible design, for a case where the communication device 1200 is used to implement the function of the second network element in the above method embodiment:

[0365] The communication unit 1202 is configured to receive a first service identifier from a first network element and to send a domain name or address corresponding to the first service identifier to the first network element based on the stored server deployment information.

[0366] In an optional implementation, the communication unit 1202 is further configured to receive fourth information from the first network element, where the fourth information is used to request a domain name or address corresponding to the first service identifier.

[0367] In an optional implementation, the first network element is a home domain session management function network element, and the communication device 1200 is a visited domain session management function network element. Alternatively, the first network element is a session management function network element, and the communication device 1200 is an intermediate session management function network element. Alternatively, the first network element is a session management function network element, and the communication device 1200 is configured to assist the session management function network element in processing server-related information.

[0368] In another possible design, for a case where the communication device 1200 is used to implement the function of the first network element in the above method embodiment:

[0369] Communication unit 1202 is used to receive fifth information from the second network element, the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address. Communication unit 1202 is also used to receive first information and the first service identifier from the application function network element, the first information is used to indicate server rediscovery. Communication unit 1202 is also used to send a first message to the terminal device based on the fifth information and the first service identifier, the first message including the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

[0370] In an optional embodiment, the communication unit 1202 sends the second information and the domain name or address corresponding to the first business identifier to the terminal device based on the fifth information and the first business identifier, and is specifically used to: when the first condition is met, send the second information and the domain name or address corresponding to the first business identifier to the terminal device based on the fifth information and the first business identifier; the first condition includes: the server deployment information of the communication device 1200 does not include the domain name and address corresponding to the first business identifier.

[0371] In an optional embodiment, communication unit 1202 is further configured to receive a data network access identifier corresponding to the first information from the application function network element. Communication unit 1202 sends the second information and a domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier. Communication unit 1202 is specifically configured to: send the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier when a second condition is met; the second condition includes: the server deployment information of communication device 1200 does not include the data network access identifier.

[0372] In an optional embodiment, the communication device 1200 belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device. The communication unit 1202 sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, and is specifically configured to: send the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier when a third condition is met; the third condition includes: the communication device 1200 does not store the server deployment information of the visited public land mobile network.

[0373] In an optional embodiment, the communication unit 1202 is further configured to receive third information from the second network element, where the third information is used to indicate a data network access identifier supported by the second network element; and the communication unit 1202 is further configured to receive a data network access identifier corresponding to the first information from the application function network element. The communication unit 1202 sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, and is specifically configured to: send the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier when a fourth condition is met; the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

[0374] In an optional implementation, the communication device 1200 is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the communication device 1200 is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the communication device 1200 is a session management function network element, and the second network element is configured to assist the session management function network element in processing server-related information.

[0375] In another possible design, for a case where the communication device 1200 is used to implement the function of the second network element in the above method embodiment:

[0376] Communication unit 1202 is configured to receive a domain name or address from a server discovery function network element. Communication unit 1202 is further configured to send fifth information to the first network element based on the domain name or address, where the fifth information indicates a correspondence between the first service identifier and the domain name, or indicates a correspondence between the first service identifier and the address.

[0377] In an optional embodiment, the communication unit 1202 sends the fifth information to the first network element based on the domain name or address, and is specifically used to: send the fifth information to the first network element based on the domain name or address when the fifth condition is met; the fifth condition includes: the communication device 1200 has stored the identifier of the access and mobility management function network element.

[0378] In an optional embodiment, the communication unit 1202 sends the fifth information to the first network element based on the domain name or address, and is specifically used to: send the fifth information to the first network element based on the domain name or address when the sixth condition is met; the sixth condition includes: the communication unit 1202 has not sent the correspondence between the first service identifier and the domain name to the first network element, and the communication unit 1202 has not sent the correspondence between the first service identifier and the address to the first network element.

[0379] In an optional implementation, the first network element is a home domain session management function network element, and the communication device 1200 is a visited domain session management function network element. Alternatively, the first network element is a session management function network element, and the communication device 1200 is an intermediate session management function network element. Alternatively, the first network element is a session management function network element, and the communication device 1200 is configured to assist the session management function network element in processing server-related information.

[0380] In an optional implementation, the second network element sends the fifth information to the first network element based on the domain name or address, including: the second network element sends the fifth information to the first network element based on the domain name or address and the stored server deployment information.

[0381] In another possible design, for a case where the communication device 1200 is used to implement the function of the first network element in the above method embodiment:

[0382] Communication unit 1202 is used to receive first information and a first service identifier from an application function network element, where the first information is used to instruct server rediscovery. Communication unit 1202 is also used to send sixth information to the application function network element, where the sixth information is used to request a domain name or address corresponding to the first service identifier. Communication unit 1202 is also used to receive a domain name or address corresponding to the first service identifier from the application function network element. Communication unit 1202 is also used to send a first message to a terminal device, where the first message includes a domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear server information corresponding to the domain name or address corresponding to the first service identifier.

[0383] In an optional embodiment, the communication unit 1202 sends the sixth information to the application function network element, specifically for: sending the sixth information to the application function network element when the first condition is met; the first condition includes: the server deployment information of the communication device 1200 does not include the domain name and address corresponding to the first service identifier.

[0384] In an optional embodiment, communication unit 1202 is further configured to receive a data network access identifier corresponding to the first information from the application function network element. Communication unit 1202 sends sixth information to the application function network element, specifically configured to: send the sixth information to the application function network element if a second condition is met; the second condition includes: the server deployment information of communication device 1200 does not include the data network access identifier.

[0385] In an optional embodiment, the communication device 1200 belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device. The communication unit 1202 sends sixth information to the application function network element, specifically configured to send the sixth information to the application function network element if a third condition is met; the third condition includes: the communication device 1200 does not store server deployment information of the visited public land mobile network.

[0386] In an optional embodiment, the communication unit 1202 is further configured to receive third information from the second network element, the third information being used to indicate a data network access identifier supported by the second network element; and the communication unit 1202 is further configured to receive the data network access identifier corresponding to the first information from the application function network element. The communication unit 1202 is configured to send sixth information to the application function network element, specifically to send the sixth information to the application function network element if a fourth condition is met, wherein the fourth condition includes: the data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

[0387] In an optional implementation, the communication device 1200 is a home domain session management function network element, and the second network element is a visited domain session management function network element. Alternatively, the communication device 1200 is a session management function network element, and the second network element is an intermediate session management function network element. Alternatively, the communication device 1200 is a session management function network element, and the second network element is configured to assist the session management function network element in processing server-related information.

[0388] In another possible design, for a case where the communication device 1200 is used to implement the functions of the application function network element in the above method embodiment:

[0389] Communication unit 1202 is configured to send first information and a first service identifier to a first network element, where the first information is used to instruct the server to rediscover the service. Communication unit 1202 is further configured to receive sixth information from the first network element, where the sixth information is used to request a domain name or address corresponding to the first service identifier. Communication unit 1202 is further configured to send the domain name or address corresponding to the first service identifier to the first network element.

[0390] The embodiments of the present application and the method embodiments shown above are based on the same concept, and the technical effects they bring are also the same. For the specific principles, please refer to the description of the embodiments shown above, and no further details will be given.

[0391] The present application also provides a communication device 1300, as shown in Figure 13. Communication device 1300 can be an SF network element or an SMF network element, or can be a chip, chip system, or processor that supports an SF network element or an SMF network element in implementing the above method. This device can be used to implement the method described in the above method embodiment. For details, please refer to the description of the above method embodiment.

[0392] The communication device 1300 may include one or more processors 1301. The processor 1301 may be configured to implement some or all of the functions of the SF network element or SMF network element described above through logic circuits or by running computer programs. The processor 1301 may be a general-purpose processor or a dedicated processor. For example, it may be a baseband processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or a CPU. The baseband processor may be configured to process communication protocols and communication data, and the central processing unit may be configured to control the communication device, execute software programs, and process data of the software programs. The communication device may be, for example, a base station, a baseband chip, a terminal, a terminal chip, a distributed unit (DU), or a centralized unit (CU).

[0393] Optionally, the communication device 1300 may include one or more memories 1302, on which instructions 1304 may be stored. The instructions may be executed on the processor 1301, causing the communication device 1300 to perform the method described in the above method embodiment. Optionally, the memory 1302 may also store data. The processor 1301 and the memory 1302 may be provided separately or integrated together.

[0394] The memory 1302 may include, but is not limited to, non-volatile memory such as a hard disk drive (HDD) or a solid-state drive (SSD), random access memory (RAM), erasable programmable ROM (EPROM), ROM or compact disc read-only memory (CD-ROM), etc.

[0395] Optionally, the communication device 1300 may further include a transceiver 1305 and an antenna 1306. The transceiver 1305 may be referred to as a transceiver unit, a transceiver, or a transceiver circuit, etc., and is configured to implement transceiver functions. The transceiver 1305 may include a receiver and a transmitter. The receiver may be referred to as a receiver or a receiving circuit, etc., and is configured to implement a receiving function; the transmitter may be referred to as a transmitter or a transmitting circuit, etc., and is configured to implement a transmitting function.

[0396] In one possible design, for a case where the communication apparatus 1300 is used to implement the function of the first network element in the above method embodiment:

[0397] Transceiver 1305 is configured to receive first information and a first service identifier from an application function network element, the first information being used to instruct server rediscovery. Transceiver 1305 is further configured to send the first service identifier to a second network element. Transceiver 1305 is further configured to receive a domain name or address corresponding to the first service identifier from the second network element. Transceiver 1305 is further configured to send a first message to a terminal device, the first message including the domain name or address corresponding to the first service identifier, the first message being used to instruct the terminal device to clear server information corresponding to the domain name or address corresponding to the first service identifier.

[0398] In another possible design, for a case where the communication device 1300 is used to implement the function of the second network element in the above method embodiment:

[0399] The transceiver 1305 is configured to receive a first service identifier from the first network element and to send a domain name or address corresponding to the first service identifier to the first network element based on the stored server deployment information.

[0400] In another possible design, for a case where the communication device 1300 is used to implement the function of the first network element in the above method embodiment:

[0401] Transceiver 1305 is configured to receive fifth information from a second network element, the fifth information being used to indicate a correspondence between the first service identifier and the domain name, or the fifth information being used to indicate a correspondence between the first service identifier and the address. Transceiver 1305 is further configured to receive first information and the first service identifier from an application function network element, the first information being used to instruct server rediscovery. Transceiver 1305 is further configured to send a first message to a terminal device based on the fifth information and the first service identifier, the first message including the domain name or address corresponding to the first service identifier, and the first message being used to instruct the terminal device to clear server information corresponding to the domain name or address corresponding to the first service identifier.

[0402] In another possible design, for a case where the communication device 1300 is used to implement the function of the second network element in the above method embodiment:

[0403] Transceiver 1305 is configured to receive a domain name or address from the server discovery function network element. Transceiver 1305 is further configured to send fifth information to the first network element based on the domain name or address, where the fifth information indicates a correspondence between the first service identifier and the domain name, or indicates a correspondence between the first service identifier and the address.

[0404] In another possible design, for a case where the communication device 1300 is used to implement the function of the first network element in the above method embodiment:

[0405] Transceiver 1305 is used to receive first information and a first service identifier from an application function network element, where the first information is used to instruct server rediscovery. Transceiver 1305 is also used to send sixth information to the application function network element, where the sixth information is used to request a domain name or address corresponding to the first service identifier. Transceiver 1305 is also used to receive a domain name or address corresponding to the first service identifier from the application function network element. Transceiver 1305 is also used to send a first message to a terminal device, where the first message includes a domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear server information corresponding to the domain name or address corresponding to the first service identifier.

[0406] In another possible design, for a case where the communication device 1300 is used to implement the functions of the application function network element in the above method embodiment:

[0407] Transceiver 1305 is configured to send first information and a first service identifier to the first network element, where the first information is used to instruct the server to rediscover the service. Transceiver 1305 is further configured to receive sixth information from the first network element, where the sixth information is used to request the domain name or address corresponding to the first service identifier. Transceiver 1305 is further configured to send the domain name or address corresponding to the first service identifier to the first network element.

[0408] In another possible design, processor 1301 may include a transceiver for implementing receiving and transmitting functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing the receiving and transmitting functions may be separate or integrated. The transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or the transceiver circuit, interface, or interface circuit may be used for transmitting or delivering signals.

[0409] In another possible design, processor 1301 may optionally store instructions 1303. Instructions 1303, when executed on processor 1301, may cause communication device 1300 to perform the method described in the above method embodiment. Instructions 1303 may be fixed in processor 1301. In this case, processor 1301 may be implemented by hardware.

[0410] In another possible design, the communication device 1300 may include a circuit that can implement the functions of sending, receiving, or communicating in the aforementioned method embodiments. The processor and transceiver described in the embodiments of the present application can be implemented in an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFIC), a mixed signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (nMetal-oxide-semiconductor, NMOS), P-type metal oxide semiconductor (positive channel metal oxide semiconductor, PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0411] Those skilled in the art will also appreciate that the various illustrative logical blocks and steps listed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of both. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the entire system. Those skilled in the art may use various methods to implement the described functions for specific applications, but such implementations should not be construed as exceeding the scope of protection of the embodiments of the present application.

[0412] The embodiments of the present application and the above-mentioned method embodiments are based on the same concept, and the technical effects they bring are also the same. For the specific principles, please refer to the description in the above-mentioned method embodiments, and no further details will be given.

[0413] The present application also provides a computer-readable storage medium for storing computer software instructions, which, when executed by a communication device, implements the functions of any of the above method embodiments.

[0414] The present application also provides a computer program product for storing computer software instructions, which, when executed by a communication device, implements the functions of any of the above method embodiments.

[0415] The present application also provides a computer program that, when executed on a computer, implements the functions of any of the above method embodiments.

[0416] The present application also provides a chip including a processor. The processor is configured to execute code or instructions to implement the functions of any of the above method embodiments. Optionally, the chip also includes an interface, the processor being coupled to the interface, and the interface being configured to receive or output signals.

[0417] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium accessible by a computer or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, an SSD).

[0418] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that, The method includes: A first network element receives first information from an application function network element and a first service identifier, where the first information is used to indicate server rediscovery; The first network element sends the first service identifier to a second network element; The first network element receives a domain name or address corresponding to the first service identifier from the second network element; The first network element sends a first message to a terminal device, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear server information corresponding to the domain name or address of the first service identifier.

2. The method according to claim 1, characterized in that The first network element sending the first service identifier to the second network element includes: The first network element sends the first service identifier to the second network element when a first condition is satisfied; The first condition includes: The server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier.

3. The method according to claim 1, characterized in that The method further includes: The first network element receives a data network access identifier corresponding to the first information from the application function network element; The first network element sending the first service identifier to the second network element includes: The first network element sends the first service identifier to the second network element when a second condition is satisfied; The second condition includes: The server deployment information of the first network element does not include the data network access identifier.

4. The method according to claim 1, wherein The first network element belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device; The first network element sending the first service identifier to the second network element includes: The first network element sends the first service identifier to the second network element when a third condition is satisfied; The third condition includes: The first network element does not store the server deployment information of the visited public land mobile network.

5. The method according to claim 1, characterized in that The method further includes: The first network element receives third information from the second network element, where the third information is used to indicate data network access identifiers supported by the second network element; The first network element receives a data network access identifier corresponding to the first information from the application function network element; The first network element sending the first service identifier to the second network element includes: The first network element sends the first service identifier to the second network element when a fourth condition is satisfied; The fourth condition includes: The data network access identifier corresponding to the first information is a data network access identifier supported by the second network element.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: The first network element sends fourth information to the second network element, where the fourth information is used to request a domain name or address corresponding to the first service identifier.

7. The method according to any one of claims 1 to 6, wherein The first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element; or, The first network element is a session management function network element, and the second network element is an intermediate session management function network element; or, The first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

8. A communication method, characterized in that, The method includes: The second network element receives a first service identifier from the first network element; Based on the stored server deployment information, the second network element sends the domain name or address corresponding to the first service identifier to the first network element.

9. The method according to claim 8, wherein The method further includes: The second network element determines the domain name or address corresponding to the first service identifier based on the stored server deployment information.

10. The method according to claim 8 or 9, characterized in that , The domain name corresponding to the first service identifier is: the domain name of the server corresponding to the first service identifier; The address corresponding to the first service identifier is: the address of the server corresponding to the first service identifier.

11. The method according to any one of claims 8 to 10, characterized in that, The method further includes: The second network element receives fourth information from the first network element, and the fourth information is used to request the domain name or address corresponding to the first service identifier.

12. The method according to any one of claims 8 to 11, wherein The first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element; or, The first network element is a session management function network element, and the second network element is an intermediate session management function network element; or, The first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

13. A communication method, characterized in that, The method includes: The first network element receives fifth information from the second network element, and the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address; The first network element receives first information and a first service identifier from the application function network element, and the first information is used to indicate server rediscovery; Based on the fifth information and the first service identifier, the first network element sends a first message to the terminal device, and the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

14. The method according to claim 13, wherein The first network element sending the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier includes: When a first condition is met, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier; The first condition includes: the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier.

15. The method according to claim 13, characterized in that, The method further includes: The first network element receives the data network access identifier corresponding to the first information from the application function network element; The first network element sending the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier includes: When the second condition is satisfied, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier; The second condition includes: the server deployment information of the first network element does not include the data network access identifier.

16. The method according to claim 13, wherein The first network element belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device; The first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: When the third condition is satisfied, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier; The third condition includes: the first network element does not store the server deployment information of the visited public land mobile network.

17. The method according to claim 13, wherein The method further includes: The first network element receives the third information from the second network element, and the third information is used to indicate the data network access identifier supported by the second network element; The first network element receives the data network access identifier corresponding to the first information from the application function network element; The first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier, including: When the fourth condition is satisfied, the first network element sends the second information and the domain name or address corresponding to the first service identifier to the terminal device based on the fifth information and the first service identifier; The fourth condition includes: the data network access identifier corresponding to the first information is the data network access identifier supported by the second network element.

18. The method according to any one of claims 13 to 17, wherein The first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element; or The first network element is a session management function network element, and the second network element is an intermediate session management function network element; or The first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

19. A communication method, characterized in that, The method includes: The second network element receives the domain name or address from the server discovery function network element; The second network element sends the fifth information to the first network element based on the domain name or address, and the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address.

20. The method according to claim 19, wherein The second network element sends the fifth information to the first network element based on the domain name or address, including: When the fifth condition is satisfied, the second network element sends the fifth information to the first network element based on the domain name or address; The fifth condition includes: the second network element has stored the identifier of the access and mobility management function network element.

21. The method according to claim 19 or 20, characterized in that, The second network element sends fifth information to the first network element based on the domain name or address, including: The second network element sends the fifth information to the first network element based on the domain name or address when a sixth condition is satisfied; The sixth condition includes: the second network element has not sent the correspondence between the first service identifier and the domain name to the first network element, and the second network element has not sent the correspondence between the first service identifier and the address to the first network element.

22. The method according to any one of claims 19 to 21, characterized in that, The second network element sends fifth information to the first network element based on the domain name or address, including: The second network element sends the fifth information to the first network element based on the domain name or address and the stored server deployment information.

23. The method according to any one of claims 19 to 22, characterized in that The first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element; or The first network element is a session management function network element, and the second network element is an intermediate session management function network element; or The first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

24. A communication method, characterized in that, The method includes: A first network element receives first information and a first service identifier from an application function network element, where the first information is used to indicate server rediscovery; The first network element sends sixth information to the application function network element, where the sixth information is used to request a domain name or address corresponding to the first service identifier; The first network element receives the domain name or address corresponding to the first service identifier from the application function network element; The first network element sends a first message to the terminal device, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear server information corresponding to the domain name or address corresponding to the first service identifier.

25. The method according to claim 24, wherein The first network element sends sixth information to the application function network element, including: The first network element sends sixth information to the application function network element when a first condition is satisfied; The first condition includes: the server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier.

26. The method according to claim 24, wherein The method further includes: The first network element receives a data network access identifier corresponding to the first information from the application function network element; The first network element sends sixth information to the application function network element, including: The first network element sends sixth information to the application function network element when a second condition is satisfied; The second condition includes: the server deployment information of the first network element does not include the data network access identifier.

27. The method according to claim 24, characterized in that The first network element belongs to the home public land mobile network of the terminal device, and the second network element belongs to the visited public land mobile network of the terminal device; The first network element sends sixth information to the application function network element, including: The first network element sends sixth information to the application function network element when a third condition is satisfied; The third condition includes: the first network element does not store the server deployment information of the visited public land mobile network.

28. The method according to claim 24, wherein The method further includes: The first network element receives third information from a second network element, where the third information is used to indicate a data network access identifier supported by the second network element; The first network element receives the data network access identifier corresponding to the first information from the application function network element; The first network element sends sixth information to the application function network element, including: The first network element sends the sixth information to the application function network element when a fourth condition is met; The fourth condition includes: the data network access identifier corresponding to the first information is the data network access identifier supported by the second network element.

29. A communication method, characterized in that, The method includes: An application function network element sends first information and a first service identifier to a first network element, where the first information is used to indicate edge application server rediscovery; The application function network element receives sixth information from the first network element, where the sixth information is used to request the domain name or address corresponding to the first service identifier; The application function network element sends the domain name or address corresponding to the first service identifier to the first network element.

30. The method according to claim 29, wherein The domain name corresponding to the first service identifier is: the domain name of the edge application server corresponding to the first service identifier; The address corresponding to the first service identifier is: the address of the edge application server corresponding to the first service identifier.

31. A communication method, characterized in that, The method includes: A first network element receives first information and a first service identifier from an application function network element, where the first information is used to indicate server rediscovery; When the first network element is unable to obtain the domain name or address corresponding to the first service identifier, the first network element sends second information to a terminal device, where the second information is used to indicate the terminal device to clear server information related to a first session, and the first session is used for the terminal device to access the service corresponding to the first service identifier.

32. The method according to claim 31, wherein The situation where the first network element is unable to obtain the domain name or address corresponding to the first service identifier includes: The server deployment information of the first network element does not include the domain name and address corresponding to the first service identifier; or, The first network element does not store the server deployment information of the visited public land mobile network; or, The server deployment information of the first network element does not include a data network access identifier; or, The data network access identifier corresponding to the first information is the data network access identifier supported by a second network element, where the first network element is a home domain session management function network element, and the second network element is a visited domain session management function network element; or, the first network element is a session management function network element, and the second network element is an intermediate session management function network element; or, the first network element is a session management function network element, and the second network element is used to assist the session management function network element in processing server-related information.

33. A communication method, characterized in that, The method includes: A first network element receives first information and a first service identifier from an application function network element, where the first information is used to indicate server rediscovery; The first network element sends the first service identifier to the second network element; The second network element receives the first service identifier from the first network element; Based on the stored server deployment information, the second network element sends the domain name or address corresponding to the first service identifier to the first network element; The first network element receives the domain name or address corresponding to the first service identifier from the second network element; The first network element sends a first message to the terminal device, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address of the first service identifier.

34. A communication method, characterized in that, The method includes: The second network element receives the domain name or address from the server discovery function network element; Based on the domain name or address, the second network element sends fifth information to the first network element, where the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address; The first network element receives the fifth information from the second network element; The first network element receives first information and a first service identifier from the application function network element, where the first information is used to indicate server rediscovery; Based on the fifth information and the first service identifier, the first network element sends a first message to the terminal device, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address of the first service identifier.

35. A communication method, characterized in that, The method includes: The application function network element sends first information and a first service identifier to the first network element, where the first information is used to indicate edge application server rediscovery; The first network element receives the first information and the first service identifier from the application function network element; The first network element sends sixth information to the application function network element, where the sixth information is used to request the domain name or address corresponding to the first service identifier; The application function network element receives the sixth information from the first network element; The application function network element sends the domain name or address corresponding to the first service identifier to the first network element; The first network element receives the domain name or address corresponding to the first service identifier from the application function network element; The first network element sends a first message to the terminal device, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address of the first service identifier.

36. A communication system, characterized in that, The system includes a first network element and a second network element; The first network element is configured to receive first information and a first service identifier from the application function network element, where the first information is used to indicate server rediscovery; The first network element is further configured to send the first service identifier to the second network element; The second network element is configured to receive the first service identifier from the first network element; The second network element is further configured to send the domain name or address corresponding to the first service identifier to the first network element based on the stored server deployment information; The first network element is further configured to receive the domain name or address corresponding to the first service identifier from the second network element; The first network element is further configured to send a first message to the terminal device, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

37. A communication system, characterized in that, The system includes a first network element and a second network element; The second network element is configured to receive the domain name or address from the server discovery function network element; The second network element is further configured to send fifth information to the first network element based on the domain name or address, where the fifth information is used to indicate the correspondence between the first service identifier and the domain name, or the fifth information is used to indicate the correspondence between the first service identifier and the address; The first network element is configured to receive the fifth information from the second network element; The first network element is further configured to receive first information and a first service identifier from the application function network element, where the first information is used to indicate server rediscovery; The first network element is further configured to send a first message to the terminal device based on the fifth information and the first service identifier, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the server information corresponding to the domain name or address corresponding to the first service identifier.

38. A communication system, characterized in that, The system includes an application function network element and a first network element; The application function network element is configured to send first information and a first service identifier to the first network element, where the first information is used to indicate edge application server rediscovery; The first network element is configured to receive the first information and the first service identifier from the application function network element; The first network element is further configured to send sixth information to the application function network element, where the sixth information is used to request the domain name or address corresponding to the first service identifier; The application function network element is further configured to receive the sixth information from the first network element; The application function network element is further configured to send the domain name or address corresponding to the first service identifier to the first network element; The first network element is further configured to receive the domain name or address corresponding to the first service identifier from the application function network element; The first network element is further configured to send a first message to the terminal device, where the first message includes the domain name or address corresponding to the first service identifier, and the first message is used to instruct the terminal device to clear the edge application server information corresponding to the domain name or address corresponding to the first service identifier.

39. A communication device, characterized in that, The device includes a module or unit for implementing the method according to any one of claims 1 to 7, or includes a module or unit for implementing the method according to any one of claims 8 to 12, or includes a module or unit for implementing the method according to any one of claims 13 to 18, or includes a module or unit for implementing the method according to any one of claims 19 to 23, or includes a module or unit for implementing the method according to any one of claims 24 to 28, or includes a module or unit for implementing the method according to claim 29 or 30, or includes a module or unit for implementing the method according to claim 31 or 32.

40. A communication device, characterized in that, including a memory and a processor; The memory is used for storing instructions or computer programs; The processor is used for executing the computer program or instructions stored in the memory, so that the communication device executes the method according to any one of claims 1 to 7, or so that the communication device executes the method according to any one of claims 8 to 12, or so that the communication device executes the method according to any one of claims 13 to 18, or so that the communication device executes the method according to any one of claims 19 to 23, or so that the communication device executes the method according to any one of claims 24 to 28, or so that the communication device executes the method according to claim 29 or 30, or so that the communication device executes the method according to claim 31 or 32.

41. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which when run, implements the method according to any one of claims 1 to 7, or implements the method according to any one of claims 8 to 12, or implements the method according to any one of claims 13 to 18, or implements the method according to any one of claims 19 to 23, or implements the method according to any one of claims 24 to 28, or implements the method according to claim 29 or 30, or implements the method according to claim 31 or 32.

42. A computer program product, the computer program product comprising: Computer program code, which when run, implements the method according to any one of claims 1 to 7, or implements the method according to any one of claims 8 to 12, or implements the method according to any one of claims 13 to 18, or implements the method according to any one of claims 19 to 23, or implements the method according to any one of claims 24 to 28, or implements the method according to claim 29 or 30, or implements the method according to claim 31 or 32.

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