Communication method and device

Abstract

The present application provides a communication method and device, which relate to the field of communication technology. It is capable of transmitting data packets of an application through a second session when a terminal initiates a query for the address information of an application through a first session. The method includes: a first network element establishes a first session for a terminal, and the first session is used to request the address information of a first application; the first network element receives first information from a second network element, and the first information includes the address information of the first application or the domain name information corresponding to the first application; the first network element triggers the terminal to establish a second session based on the first information; the second session is used to serve the first application; when the second session is successfully established, the first network element sends a first indication message to the second network element; the first indication message is used to instruct the second network element to send a second message to the terminal, and the second information includes the address information of the first application. The present application is applied to transmitting data packets.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular to a communication method and apparatus. Background Art

[0002] Currently, in the prior art, after a user equipment (UE) initiates a Domain Name System (DNS) query through a protocol data unit (PDU) session to obtain the address information of an application (e.g., an edge application), the UE can transmit data packets of the application through the session. If the user plane path of the PDU session is not optimized enough, the UE needs to establish a new PDU session and re-initiate a DNS query through the new PDU session to obtain the address information of the application, so that the UE transmits the data packets of the application through the new PDU session. This may cause business interruption of the application and affect the quality of service.

[0003] Therefore, in this case, how to transmit the data message of the application through a new PDU session and avoid service interruption of the application is a problem that needs to be solved at present. Summary of the Invention

[0004] An embodiment of the present application provides a communication method and apparatus for transmitting data packets of an application through another PDU session when a terminal initiates a query for address information of the application through one PDU session.

[0005] In a first aspect, a communication method is provided, including: a first network element establishing a first session for a terminal, the first session being used to request address information of a first application. The first network element receives first information from a second network element, the first information including the address information of the first application or domain name information corresponding to the first application. Based on the first information, the first network element triggers the terminal to establish a second session, the second session being used to serve the first application. When the second session is successfully established, the first network element sends first indication information to the second network element, the first indication information being used to instruct the second network element to send second information to the terminal, the second information including the address information of the first application.

[0006] In the above method, when a terminal needs to access a first application (i.e., the terminal needs to transmit data packets of the first application), after a first network element establishes a first session for the terminal and the first network element receives first information from a second network element, the first network element can first trigger the terminal to establish a second session based on the first information. Then, after the second session is successfully established, the first network element sends first indication information to the second network element, causing the second network element to send second information containing the address information of the first application to the terminal. This allows the terminal to obtain the second information after the second session is successfully established and access the first application based on the address information of the first application contained in the second information. In this way, since the second session has already been successfully established before the terminal accesses the first application, the terminal can access the first application through the second session without first having to access the first application through the first session. This avoids the problem of service interruption caused by session switching in the prior art.

[0007] In one possible design, the method further includes: the first network element sending subscription information to the third network element. The subscription information is used to instruct the third network element to send subscription notification information to the first network element after determining that the second session is successfully established. When the second session is successfully established, the first network element sends first indication information to the second network element, including: after receiving the subscription notification information, the first network element sends the first indication information to the second network element.

[0008] Through the above design, the first network element can determine that the second session has been successfully established by receiving subscription notification information.

[0009] In one possible design, the third network element is an access and mobility management function AMF network element or a unified data management function UDM network element.

[0010] In one possible design, the first network element triggers the terminal to establish a second session based on the first information, including: the first network element sends fifth indication information to the fourth network element based on the first information, and the fifth indication information is used to instruct the fourth network element to select the first network element to serve the second session.

[0011] In the above design, the first network element sends the fifth indication information to the fourth network element, so that the first network element serves the second session, thereby enabling the first network element to sense whether the second session is successfully established.

[0012] In one possible design, the first network element is a session management function SMF network element.

[0013] In one possible design, the method also includes: the first network element sends second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

[0014] Through the above design, the second network element can save the second information and the first information until the second session is successfully established, and then send the second information to the terminal.

[0015] In one possible design, the second information is domain name system response DNS response information.

[0016] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0017] In one possible design, the second information may also include domain name information corresponding to the first application.

[0018] According to a second aspect, a communication method is provided, including: a terminal establishing a first session, the first session being used to request address information of a first application; the terminal receiving third indication information from a first network element, the third indication information being used to indicate establishment of a second session, the second session being used to serve the first application; the terminal establishing a second session based on the third indication information; when the terminal receives second information from the second network element, the second information including the address information of the first application, the terminal transmits a data message of the first application through the second session.

[0019] In one possible design, the second information is domain name system response DNS response information.

[0020] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0021] In one possible design, the second information may also include domain name information corresponding to the first application.

[0022] According to a third aspect, a communication method is provided, including: a first network element establishes a first session for a terminal, the first session is used to request address information of a first application; the first network element receives first information from a second network element, the first information including address information of the first application or domain name information corresponding to the first application; the first network element sends fourth indication information to the terminal based on the first information, the fourth indication information including at least one of the address information of the first application, the domain name information corresponding to the first application, or identification information of the first application, the fourth indication information being used to instruct the terminal to transmit data packets of the first application through the second session.

[0023] In the above method, when a terminal needs to access a first application (i.e., the terminal needs to transmit data packets of the first application), after the first network element establishes a first session for the terminal and the first network element receives first information from the second network element, the first network element can send fourth instruction information to the terminal based on the first information, instructing the terminal to access the first application through the second session. In this way, the terminal can access the first application through the second session instead of the first session based on the fourth instruction information. This avoids the problem of service interruption caused by session switching in the prior art.

[0024] In one possible design, the method also includes: after the terminal receives the fourth indication information, the first network element sends the first indication information to the second network element, and the first indication information is used to instruct the second network element to send the second information to the terminal; the second information includes the address information of the first application.

[0025] Through the above design, the terminal can receive the fourth indication information first and then receive the second information, so that the terminal knows that it needs to access the first application through the second session before accessing the first application according to the second information, avoiding the terminal accessing the first application through the first session.

[0026] In one possible design, the method also includes: the first network element sends second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

[0027] Through the above design, the second network element can save the second information and the first information until the second session is successfully established, and then send the second information to the terminal.

[0028] In one possible design, the second information is domain name system response DNS response information.

[0029] In one possible design, the second information may also include domain name information corresponding to the first application.

[0030] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0031] In a fourth aspect, a communication method is provided, including: a terminal establishes a first session, the first session is used to request address information of a first application; the terminal receives fourth indication information from a first network element, the fourth indication information includes at least one of the address information of the first application, domain name information corresponding to the first application, or identification information of the first application, and the fourth indication information is used to instruct the terminal to transmit a data message of the first application through a second session; when the terminal receives the address information from the second network element or the domain name information corresponding to the first application, the terminal transmits the data message of the first application through the second session.

[0032] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0033] According to a fifth aspect, a communication method is provided, comprising: a third network element receiving subscription information from a first network element, and sending subscription notification information to the first network element after a second session is successfully established based on the subscription information.

[0034] In one possible design, the third network element is an access and mobility management function AMF network element or a unified data management function UDM network element.

[0035] In a sixth aspect, a communication method is provided, comprising: a first network element establishing a first session for a terminal, the first session being used to request address information of a first application. The first network element receives first information from a second network element, the first information including address information of the first application or domain name information corresponding to the first application. Based on the first information, the first network element triggers the terminal to establish a second session, the second session being used to serve the first application. The terminal receives third indication information from the first network element, the third indication information being used to instruct the establishment of a second session. The terminal establishes the second session based on the third indication information. When the second session is successfully established, the first network element sends first indication information to the second network element, the first indication information being used to instruct the second network element to send second information to the terminal, the second information including address information of the first application. When the terminal receives second information from the second network element, the second information including address information of the first application, the terminal transmits data packets of the first application through the second session.

[0036] In one possible design, the method further includes: the first network element sending subscription information to the third network element, where the subscription information is used to instruct the third network element to send subscription notification information to the first network element after determining that the second session is successfully established. When the second session is successfully established, the first network element sends first indication information to the second network element, including: after receiving the subscription notification information, the first network element sends the first indication information to the second network element.

[0037] In one possible design, the third network element is an access and mobility management function AMF network element or a unified data management function UDM network element.

[0038] In one possible design, the first network element triggers the terminal to establish a second session based on the first information, including: the first network element sends fifth indication information to the fourth network element based on the first information, and the fifth indication information is used to instruct the fourth network element to select the first network element to serve the second session.

[0039] In one possible design, the first network element is a session management function SMF network element.

[0040] In one possible design, the method also includes: the first network element sends second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

[0041] In one possible design, the second information is domain name system response DNS response information.

[0042] In one possible design, the second information may also include domain name information corresponding to the first application.

[0043] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0044] In a seventh aspect, a communication method is provided, including: a first network element establishes a first session for a terminal, the first session being used to request address information of a first application. The first network element receives first information from a second network element, the first information including address information of the first application or domain name information corresponding to the first application. Based on the first information, the first network element sends fourth indication information to the terminal, the fourth indication information including at least one of the address information of the first application, the domain name information corresponding to the first application, or identification information of the first application, the fourth indication information being used to instruct the terminal to transmit a data message of the first application through a second session. When the terminal receives the address information or the domain name information corresponding to the first application from the second network element, the terminal transmits the data message of the first application through the second session.

[0045] In one possible design, the method also includes: after the terminal receives the fourth indication information, the first network element sends the first indication information to the second network element, and the first indication information is used to instruct the second network element to send second information to the terminal, and the second information includes address information of the first application.

[0046] In one possible design, the method also includes: the first network element sends second indication information to the second network element, and the second indication information is used to instruct the second network element to cache the second information.

[0047] In one possible design, the second information is domain name system response DNS response information.

[0048] In one possible design, the second information may also include domain name information corresponding to the first application.

[0049] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0050] In an eighth aspect, a communication system is provided, comprising: a first network element and a terminal; the first network element is used to execute a method as described in the first aspect or any one of the designs in the first aspect; the terminal is used to execute a method as described in the second aspect or any one of the designs in the second aspect.

[0051] In the ninth aspect, a communication system is provided, including: a first network element and a terminal; the first network element is used to execute the method as described in the third aspect or any one of the designs in the third aspect; the terminal is used to execute the method as described in the fourth aspect or any one of the designs in the fourth aspect.

[0052] In a tenth aspect, a communication device is provided, which may be a chip or a system-on-chip. The communication device may implement the functions performed by the first network element in the first aspect or the possible design of the first aspect. These functions may be implemented through hardware or through hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include: a processing unit, configured to establish a first session for a terminal, the first session being used to request address information of a first application. A communication unit, configured to receive first information from a second network element, the first information including address information of the first application or domain name information corresponding to the first application. The processing unit is further configured to trigger the terminal to establish a second session based on the first information, the second session being used to serve the first application. The communication unit is further configured to send first indication information to the second network element when the second session is successfully established, the first indication information being used to instruct the second network element to send second information to the terminal, the second information including address information of the first application.

[0053] In one possible design, the communication unit is further configured to send subscription information to a third network element, where the subscription information is used to instruct the third network element to send subscription notification information to the communication device after determining that the second session is successfully established. The communication unit is further configured to send first indication information to the second network element when the second session is successfully established, including: the communication unit is specifically configured to send the first indication information to the second network element after receiving the subscription notification information.

[0054] In one possible design, the third network element is an access and mobility management function AMF network element or a unified data management function UDM network element.

[0055] In one possible design, the processing unit is also used to trigger the terminal to establish a second session based on the first information, including: the processing unit is specifically used to send fifth indication information to the fourth network element based on the first information, and the fifth indication information is used to instruct the fourth network element to select a communication device to serve the second session.

[0056] In one possible design, the communication device is a session management function SMF network element.

[0057] In one possible design, the communication unit is also used to send second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

[0058] In one possible design, the second information is domain name system response DNS response information.

[0059] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0060] In an eleventh aspect, a communication device is provided, which may be a chip or a system on chip. The communication device may implement the functions performed by the terminal in the second aspect or the possible design of the second aspect. These functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include: a processing unit for establishing a first session, the first session being used to request address information of a first application. A communication unit for receiving third indication information from a first network element, the third indication information being used to indicate the establishment of a second session, the second session being used to serve the first application. The processing unit is further used to establish a second session based on the third indication information. The processing unit is further used to transmit a data message of the first application through the second session when the communication device receives second information from a second network element, the second information including the address information of the first application.

[0061] In one possible design, the second information is domain name system response DNS response information.

[0062] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0063] In a twelfth aspect, a communication device is provided, which may be a chip or a system on chip. The communication device may implement the functions performed by the first network element in the third aspect or the possible design of the third aspect. These functions may be implemented by hardware or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include: a processing unit, configured to establish a first session for a terminal, the first session being used to request address information of a first application. A communication unit, configured to receive first information from a second network element, the first information including address information of the first application or domain name information corresponding to the first application. The communication unit is further configured to send fourth indication information to the terminal based on the first information, the fourth indication information including at least one of address information of the first application, domain name information corresponding to the first application, or identification information of the first application, the fourth indication information being used to instruct the terminal to transmit data packets of the first application through the second session.

[0064] In one possible design, the communication unit is also used to send first indication information to the second network element after the terminal receives the fourth indication information, and the first indication information is used to instruct the second network element to send second information to the terminal; the second information includes address information of the first application.

[0065] In one possible design, the communication unit is also used to send second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

[0066] In one possible design, the second information is domain name system response DNS response information.

[0067] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0068] In a thirteenth aspect, a communication device is provided, which may be a chip or a system-on-chip. The communication device may implement the functions performed by the terminal in the fourth aspect or the possible design of the fourth aspect. These functions may be implemented by hardware or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include: a processing unit for establishing a first session, the first session being used to request address information of a first application. A communication unit for receiving fourth indication information from a first network element, the fourth indication information including at least one of address information of the first application, domain name information corresponding to the first application, or identification information of the first application, the fourth indication information being used to instruct the terminal to transmit data packets of the first application via a second session. The processing unit is further configured to, when the terminal receives address information or domain name information corresponding to the first application from the second network element, transmit data packets of the first application via the second session.

[0069] In one possible design, the first session and the second session are sessions in service continuity mode SSC mode 3.

[0070] In a fourteenth aspect, a communication device is provided, which may be a chip or a system on chip. The communication device may implement the functions performed by the third network element in the fifth aspect or the possible design of the fifth aspect. These functions may be implemented by hardware or by hardware executing corresponding software implementations. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device may include a communication unit for receiving subscription information from the first network element. The communication unit is also used for the third network element to send subscription notification information to the first network element after determining that the second session is successfully established based on the subscription information.

[0071] In one possible design, the third network element is an access and mobility management function AMF network element or a unified data management function UDM network element.

[0072] In the fifteenth aspect, a communication device is provided, comprising: at least one processor and a communication interface, wherein when the processor executes computer program instructions, the communication device executes the method of the above-mentioned first aspect or any one of the designs of the first aspect, or the communication device executes the method of the above-mentioned third aspect or any one of the designs of the third aspect.

[0073] In the sixteenth aspect, a communication device is provided, comprising: at least one processor and a communication interface. When the processor executes computer program instructions, the communication device executes the method of any one of the second aspect or the designs of the second aspect, or the communication device executes the method of the fourth aspect or the designs of the fourth aspect.

[0074] In the seventeenth aspect, a communication device is provided, comprising: at least one processor and a communication interface, wherein when the processor executes computer program instructions, the communication device executes the method of the above-mentioned fifth aspect or any one of the designs of the fifth aspect.

[0075] In the eighteenth aspect, a chip is provided, which includes a processor. When the processor executes computer program instructions, the chip executes the method of the first aspect or any one of the designs of the first aspect, or the second aspect or any one of the designs of the second aspect, or the third aspect or any one of the designs of the third aspect, or the fourth aspect or any one of the designs of the fourth aspect, or the fifth aspect or any one of the designs of the fifth aspect.

[0076] In the nineteenth aspect, a computer-readable storage medium is provided, comprising: computer software instructions; when the computer software instructions are executed in a communication device or a chip built into the communication device, the communication device executes the method of the above-mentioned first aspect or any one of the designs of the first aspect, or the above-mentioned second aspect or any one of the designs of the second aspect, or the above-mentioned third aspect or any one of the designs of the third aspect, or the above-mentioned fourth aspect or any one of the designs of the fourth aspect, or the above-mentioned fifth aspect or any one of the designs of the fifth aspect.

[0077] In the twentieth aspect, a computer program product is provided, characterized in that the computer program product includes instructions, which, when the computer program product is run on a computer, enables the computer to execute the method of the first aspect or any one of the designs of the first aspect, or the second aspect or any one of the designs of the second aspect, or the third aspect or any one of the designs of the third aspect, or the fourth aspect or any one of the designs of the fourth aspect, or the fifth aspect or any one of the designs of the fifth aspect.

[0078] Illustratively, any design method in the second aspect and aspects 4 to 20 can correspond to the above-mentioned first aspect and any possible design thereof or the third aspect and any possible design thereof, and therefore, can bring similar technical effects, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 A schematic diagram of the SSC mode 3 process provided in an embodiment of the present application;

[0080] Figure 2 A schematic diagram of a network structure provided in an embodiment of the present application;

[0081] Figure 3 This is one of the schematic diagrams of the composition of a communication device provided in an embodiment of the present application;

[0082] Figure 4 One of the flow charts of a communication method provided in an embodiment of the present application;

[0083] Figure 5 A second flow chart of a communication method provided in an embodiment of the present application;

[0084] Figure 6 The third flowchart of a communication method provided in an embodiment of the present application;

[0085] Figure 7 A fourth flow chart of a communication method provided in an embodiment of the present application;

[0086] Figure 8 A fifth flow chart of a communication method provided in an embodiment of the present application;

[0087] Figure 9 Schematic diagram of a communication method according to an embodiment of the present application;

[0088] Figure 10 Schematic diagram of a communication method according to an embodiment of the present application;

[0089] Figure 11 8. Flowchart of a communication method according to an embodiment of the present application;

[0090] Figure 12 9. Flowchart diagram of a communication method provided in an embodiment of the present application;

[0091] Figure 13 This is a tenth flowchart of a communication method provided in an embodiment of the present application;

[0092] Figure 14This is a second schematic diagram of the composition of a communication device provided in an embodiment of the present application;

[0093] Figure 15 This is a third schematic diagram of the composition of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0094] In the description of this application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, "at least one" means one or more, and "a plurality" means two or more. Words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not limit them to be necessarily different.

[0095] It should be noted that, in this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0096] In the description of this application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the first indication information described below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated. For example, the information to be indicated can be directly indicated, wherein the information to be indicated itself or the index of the information to be indicated, etc. For another example, the information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association relationship between the other information and the information to be indicated. For another example, only a part of the information to be indicated can be indicated, while the other parts of the information to be indicated are known or agreed in advance. In addition, the indication of specific information can be achieved by means of the arrangement order of each information agreed in advance (such as specified by the protocol), thereby reducing the indication overhead to a certain extent.

[0097] In order to facilitate understanding of the technical solution of this application, the technology involved in this application is briefly introduced below.

[0098] Session and service continuity mode (SSC mode)

[0099] Currently, in order to support the continuity of PDU sessions, communication networks can support multiple SSC modes to meet the continuity requirements of different applications or services. Taking 5G networks as an example, the SSC modes supported in 5G networks mainly include the following three:

[0100] 1) SSC mode 1: During the mobility of the UE, regardless of the UE access technology type and the UE location, after the PDU session is established, the UPF serving as the PDU session anchor (PSA) remains unchanged.

[0101] 2) SSC mode 2: Based on the operator's policy and other information, the network side can release the current PDU session and notify the UE to re-establish a new PDU session. In the new PDU session, the UPF as the PSA can be reselected.

[0102] 3) SSC mode 3: For PDU sessions in SSC mode 3, the network allows a connection to be established through a new PDU session anchor before the connection between the UE and the previous PDU session anchor is released. That is to say, when migrating the anchor point, a PDU session connection through the new anchor point is first established (accessing the same data network name (DN)), and then the old anchor point PDU session connection is released. The difference from SSC mode 2 is that SSC mode 3 first establishes a connection to the new anchor point and then releases the connection to the old anchor point to ensure service continuity, while SSC mode 2 first releases the old anchor point connection and then immediately establishes a new anchor point connection to ensure service continuity.

[0103] Specifically, the specific process of SSC mode 3 can be as follows Figure 1 Shown, including:

[0104] S1. SMF decides the service SMF and UPF to migrate the PDU session.

[0105] S2, SMF sends Namf_Communication_N1N2MessageTransfer to AMF. Among them, Namf_Communication_N1N2MessageTransfer may include: PDU Session ID and N1 SM container (N1SMContainer). PDU Session ID is used to identify the PDU session to be migrated (i.e., old PDU session), and N1 SMContainer includes: PDU Session Modification Command (PDU Session Modification Command). The PDU Session Modification Command includes: Cause value and PDU Session Address Lifetime value (PDU Session Address Lifetimevalue). Among them, the Cause value indicates that the UE should immediately re-initiate the PDU session connection with the same DN. PDU SessionAddress Lifetime value indicates how long the network will continue to retain the current PDU session. After the timeout, SMF will initiate the PDU session release process.

[0106] S3. AMF sends a PDU session modification command (PDU Session Modification Command) to the UE. For example, AMF sends the above-mentioned N1 SM Container to the UE.

[0107] S4. After receiving the PDU session modification command, the UE initiates a new PDU session establishment process, where the new PDU session has the same DN as the old PDU session.

[0108] S5. After establishing the new PDU session, the UE begins using the IP address / prefix associated with the new PDU session for all new traffic and may also proactively move existing traffic flows (if possible) from the old PDU session to the new PDU session. After the new session is established, both uplink and downlink data are transmitted over the new PDU session and no longer over the old PDU session.

[0109] S6. The UE can release the old PDU session before the PDU Session Address Lifetime expires, or the SMF initiates the release process of the old PDU session after the PDU Session Address Lifetime expires.

[0110] The technical solutions provided in the embodiments of this application can be applied to various communication systems, such as 5G communication systems, future evolution systems, or multiple communication convergence systems. The technical solutions provided in this application can be applied to various application scenarios, such as machine-to-machine (M2M), macro-micro communication, enhanced mobile broadband (eMBB), ultra-reliable and low latency communication (uRLLC), and massive machine type communication (mMTC).

[0111] In addition, 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 can 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.

[0112] like Figure 2 The figure shows the architecture of a 5G network to which the technical solutions provided in the embodiments of the present application are applicable. The 5G network may include: a terminal, namely user equipment (UE) in the figure, a radio access network (RAN) or an access network (AN) (hereinafter referred to as (R)AN), a core network (CN), and a data network (DN).

[0113] Among them, the terminal can be a device with wireless transceiver function. The terminal can have different names, such as UE, access terminal, terminal unit, terminal station, mobile station, mobile station, remote station, remote terminal, mobile device, wireless communication device, terminal agent or terminal device, etc. The terminal can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; it can also be deployed on the water surface (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.). The terminal includes a handheld device, vehicle-mounted device, wearable device or computing device with wireless communication function. Exemplarily, the terminal can be a mobile phone, a tablet computer or a computer with wireless transceiver function. The terminal device can also be a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in telemedicine, a wireless terminal in smart grid, a wireless terminal in smart city, a wireless terminal in smart home, etc. In the embodiments of the present application, the device for implementing the functions of the terminal may be a terminal, or a device capable of supporting the terminal in implementing the functions, such as a chip system. In the embodiments of the present application, the chip system may be composed of a chip, or may include a chip and other discrete components. In the embodiments of the present application, the technical solutions provided in the embodiments of the present application are described using the terminal as an example.

[0114] Access network equipment can also be referred to as a base station. Base stations can include various types of base stations, such as macro base stations, micro base stations (also known as small base stations), relay stations, and access points. Specifically, they can be: Evolved Node B (eNB or eNodeB) in LTE, or relay stations or access points, or vehicle-mounted devices, wearable devices, and the next generation Node B (gNB) in 5G networks, or base stations in future evolved public land mobile networks (PLMNs), or other network elements with base station functions in the future.

[0115] A base station typically consists of a baseband unit (BBU), a remote radio unit (RRU), an antenna, and the feeder cables connecting the RRU and antenna. The BBU is responsible for signal modulation. The RRU is responsible for RF processing. The antenna converts the guided waves on the cable into airborne waves. Distributed base stations significantly shorten the feeder cable between the RRU and antenna, reducing signal loss and lowering feeder costs. Furthermore, the RRU and antenna are relatively compact and can be installed anywhere, making network planning more flexible. In addition to remote RRUs, all BBUs can be centralized and placed in a central office (CO). This centralized approach significantly reduces the number of base station equipment rooms and the energy consumption of supporting equipment, especially air conditioning, significantly reducing carbon emissions. Furthermore, by centralizing distributed BBUs into a BBU baseband pool, unified management and scheduling are possible, making resource allocation more flexible. In this model, all physical base stations become virtual base stations. All virtual base stations share user data transmission and reception, channel quality and other information in the BBU baseband pool, and cooperate with each other to achieve joint scheduling.

[0116] In some deployments, a base station may include a centralized unit (CU) and a distributed unit (DU). The base station may also include an active antenna unit (AAU). The CU implements some of the base station's functions, while the DU implements some of the base station's functions. For example, the CU is responsible for processing non-real-time protocols and services, implementing the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers. The DU is responsible for processing physical layer protocols and real-time services, implementing the functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. The AAU implements some physical layer processing functions, RF processing, and active antenna-related functions. Since RRC layer information will eventually become PHY layer information, or be converted from PHY layer information, in this architecture, higher-layer signaling, such as RRC layer signaling or PDCP layer signaling, can also be considered to be sent by the DU, or by the DU+AAU. It is understood that in the embodiments of the present application, the access network device may include one or more of a CU node, a DU node, and an AAU node. In addition, the CU may be classified as a network device in the RAN, or the CU may be classified as a network device in the core network (CN), without limitation herein.

[0117] In one possible design, the base station can separate the control plane (CP) and user plane (UP) of the CU and implement them as different entities. That is, the CU can be divided into CU-CP and CU-UP.

[0118] The core network includes multiple core network elements (or network function network elements), such as access and mobility management function (AMF) network element, session management function (SMF) network element, user plane function (UPF) network element, unified data management (UDM) network element, application layer function (AF) network element, policy control function (PCF) network element, authentication server function (AUSF) network element, edge application server discovery function (EASDF) network element and network exposure function (NEF) network element.

[0119] The AMF network element is responsible for user mobility management, including mobility status management, allocation of temporary user identities, authentication and authorization of users. The SMF network element is responsible for UP network element selection, UP network element reselection, IP address allocation, bearer establishment, modification and release, and QoS control. The PCF network element includes policy control decision-making and flow-based charging control functions, including user subscription data management functions, policy control functions, charging policy control functions, QoS control, etc. The UDM network element is responsible for managing subscription data and notifying the corresponding network elements when the subscription data is modified. The EASDF network element is responsible for receiving DNS query messages from the UE and receiving DNS response messages from the DNS server. When the fully qualified domain name (FQDN) contained in the DNS response message is the FQDN of the edge application server or when the IP address contained in the DNS response message is the IP address of the edge application server, the EASDF is responsible for sending a notification message to the SMF.

[0120] It should be noted that the core network element may have other names, and the embodiments of the present application are not limited thereto. For example, the AMF network element may also be referred to as AMF or AMF entity, and the UPF network element may also be referred to as UPF or UPF entity, etc.

[0121] Among them, the terminal communicates with the AMF through the next generation network (Next generation, N) 1 interface (referred to as N1), the RAN device communicates with the AMF through the N2 interface (referred to as N2), the RAN device communicates with the UPF through the N3 interface (referred to as N3), and the UPF communicates with the DN through the N6 interface (referred to as N6).

[0122] AMF, SMF, UDM, AUSF, or PCF and other control planes can also use service-oriented interfaces for interaction. Figure 2 As shown, the service interface provided by AMF to the outside world may be Namf; the service interface provided by SMF to the outside world may be Nsmf; the service interface provided by UDM to the outside world may be Nudm; the service interface provided by PCF to the outside world may be Npcf, which will not be described one by one here.

[0123] Optionally, the devices mentioned in the embodiments of the present application, such as terminals, core network elements, etc., can be Figure 3 The communication device shown is implemented.

[0124] like Figure 3 As shown, the device 10 includes at least one processor 101 , a communication line 102 , a memory 103 and at least one communication interface 104 .

[0125] The processor 101 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

[0126] The communication link 102 may include a pathway for transmitting information between the aforementioned components.

[0127] The communication interface 104 , which uses any transceiver or other device, is used to communicate with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), etc.

[0128] The memory 103 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor via the communication line 102. The memory may also be integrated with the processor.

[0129] The memory 103 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 101. The processor 101 is used to execute the computer-executable instructions stored in the memory 103, thereby implementing the message transmission method provided in the following embodiments of the present application.

[0130] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0131] In a specific implementation, as an embodiment, the processor 101 may include one or more CPUs, such as Figure 3 CPU0 and CPU1 in.

[0132] In a specific implementation, as an embodiment, the device 10 may include multiple processors, such as Figure 3 1 and 107. Each of these processors may be a single-CPU processor or a multi-CPU processor. A processor herein may refer to one or more devices, circuits, and / or processing cores for processing, for example, computer data (computer program instructions).

[0133] In a specific implementation, as an embodiment, the apparatus 10 may further include an output device 105 and an input device 106. The output device 105 communicates with the processor 101 and can display information in a variety of ways. For example, the output device 105 can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 106 communicates with the processor 101 and can receive user input in a variety of ways. For example, the input device 106 can be a mouse, a keyboard, a touch screen device, or a sensor device.

[0134] The technical solutions provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0135] Currently, after a terminal initiates a DNS query through a PDU session (referred to as the first PDU session) to obtain the application's address information, the UE can transmit the application's data packets through this session. If the user plane path of the first PDU session is not optimized enough, the terminal re-establishes a new PDU session (the second PDU session) and re-initiates a DNS query request message through the second PDU session to obtain the application's address information. The terminal then transmits the application's data packets through the second PDU session. This may cause service interruption for the application, affecting service quality.

[0136] In order to avoid the above problems, an embodiment of the present application enables the terminal to obtain the address information of the application through the first PDU session, and then transmit the data packet of the application through the second PDU session, thereby avoiding the problem of service interruption caused by the terminal first transmitting the data packet of the application through the first PDU session and then transmitting the data packet of the application through the second PDU session.

[0137] Furthermore, in order to achieve the purpose of transmitting the application data message through the second PDU session after the terminal obtains the address information of the application, without having to transmit the application data message through the first PDU session first, the embodiment of the present application provides the following two methods:

[0138] Method 1: After the terminal initiates a DNS request through the first PDU session, if the network determines that a second PDU session is needed to transmit the application's data packets, the network triggers the terminal to first establish the second PDU session. After the second PDU session is successfully established, the network then sends the application's address information to the terminal. This prevents the terminal from transmitting application data packets through the first PDU session.

[0139] Method 2: After the terminal initiates a DNS request through the first PDU session, if the network determines that a second PDU session needs to be established to transmit the application's data packets, the network sends an instruction to the terminal, instructing the terminal to transmit the application's data packets through the second PDU session after the second PDU session is successfully established. This also prevents the terminal from transmitting application data packets through the first PDU session.

[0140] The following describes the implementation process of the above two methods:

[0141] First, with respect to the aforementioned method 1, the communication method provided in the embodiment of the present application is as follows: Figure 4 As shown, this may include:

[0142] S201: Establish a first session for a terminal.

[0143] The first session may be a PDU session. In order to establish the second session before the first session is released, the first session may be a PDU session of SSC mode 3.

[0144] The first session is used to request the address information of the first application. For example, after the first session is established, the terminal sends a DNS query message through the first session. The DNS query message carries the domain name information corresponding to the first application. The DNS query message is used to request the address information of the first application. Exemplarily, the address information of the first application can be an IP address, and the domain name information corresponding to the first application can be a fully qualified domain name (FQDN).

[0145] On the one hand, from the perspective of a network element for session management in the network (hereinafter referred to as a first network element), S201 may include: the first network element establishes a first session for the terminal.

[0146] For example, the first network element may be an SMF in a 5G network, and S201 may be understood as: the SMF establishes a first session for the terminal through the steps performed by the SMF in the PDU session establishment process.

[0147] Exemplarily, in a 5G network, the PDU session establishment process may include: 1. The terminal initiates the PDU session establishment process. Specifically, the terminal carries parameters such as the PDU session identifier, SSC mode, single network slice selection assistance information (S-NSSAI) and data network name (DNN) and sends them to the AMF. 2. The AMF selects the SMF based on the S-NSSAI and DNN, and sends the AMF network element identifier, the terminal's permanent identifier, the terminal's location information, the PDU session identifier, S-NSSAI and DNN and other parameters to the SMF network element. Among them, the terminal's location information may include the terminal's tracking area identity (TAI). 3. The SMF selects the anchor point UPF and EASDF for the PDU session, and sends configuration information to the EASDF network element. The configuration information is used by the EASDF to monitor the DNS response message. 4. The terminal obtains the IP address of the EASDF (for example, the terminal obtains the IP address of the EASDF from the PDU session acceptance message), and uses the IP address as the destination address of the DNS query message subsequently initiated through the first session.

[0148] Then, from the perspective of the SMF, S201 may include the following steps: the SMF selects the anchor points UPF and EASDF for the PDU session, and sends configuration information to the EASDF network element, etc. The configuration information is used by the EASDF to monitor the DNS response message.

[0149] On the other hand, from the perspective of the terminal, S201 may include: the terminal establishing a first session. For example, in a 5G network, S201 may include: the terminal establishing the first session through the steps performed by the terminal in the PDU session establishment process. Specifically, taking the above-mentioned PDU session establishment process in the 5G network as an example, S201 may include: the terminal initiating the PDU session establishment process, and the terminal obtaining the IP address of the EASDF and using the IP address as the destination address of the DNS query message subsequently initiated through the first session.

[0150] S202. The first network element receives first information from the second network element.

[0151] The first information includes the address information of the first application or the domain name information corresponding to the first application. For example, the address information of the first application may be an IP address, and the domain name information corresponding to the first application may be a fully qualified domain name (FQDN).

[0152] It should be noted that the first information referred to in the embodiments of the present application includes the address information of the first application or the domain name information corresponding to the first application, which can be understood as: the first information includes at least one of the address information of the first application or the domain name information corresponding to the first application. In other words, during the implementation of the embodiments of the present application, the first information may include the address information of the first application, or the first information may include the domain name information corresponding to the first application, or the first information may include the address information of the first application and the domain name information corresponding to the first application. This embodiment of the present application is not limited to this.

[0153] The second network element may be a network element that receives a DNS query message from the terminal and a DNS response message from the DNS server. For example, the second network element may be an EASDF network element in a 5G network.

[0154] In conjunction with the description of step S201, since the terminal obtains the IP address of the EASDF during the session establishment process, when the terminal needs to obtain the address information of the first application, the terminal can send a DNS query message to the EASDF, where the destination address of the DNS query message is the IP address of the EASDF, and the DNS query message carries the FQDN corresponding to the first application. The EASDF sends the DNS query message to the DNS server and receives a DNS response message from the DNS server, where the DNS response message includes the address information of the first application and the domain name information corresponding to the first application.

[0155] That is to say, after the first session is successfully established, the second network element can send the address information of the first application requested by the terminal through the first session or the domain name information corresponding to the first application to the first network element, so that the first network element can determine whether to trigger the terminal to establish a new session to transmit the data packet of the first application.

[0156] For example, when the first network element is SMF and the second network element is EASDF, Figure 5 As shown, after establishing the first session for the terminal in S301, first, refer to Figure 5 In S302, the terminal can send a DNS query request (DNS query) to the UPF through the access network device according to business needs to initiate a DNS query for the first application, wherein the DNS query can carry the domain name corresponding to the first application, which can be a FQDN or other form of domain name. In addition, the destination address included in the DNS query is the IP address of the EASDF. Then, as Figure 5In S303, UPF sends the DNS query request to EASDF. Then, after EASDF sends the DNS query request to the DNS server, it can receive the DNS response message from the DNS server and monitor the FQDN or IP address carried in the DNS response message according to the configuration information sent by SMF. Figure 5 In S304, the EASDF may send a first message to the SMF, where the first message carries the FQDN or IP address in the DNS response message.

[0157] That is to say, when this method is applied in a 5G network, S202 can be understood as: Figure 5 S304 in.

[0158] S203: The first network element triggers the terminal to establish a second session according to the first information.

[0159] The second session is used to serve the first application. The second session may be a PDU session.

[0160] Among them, the first network element triggers the terminal to establish a second session, which can be understood as: the first network element uses a preset process, such as sending a message or indication (such as the third indication information below) to the terminal or other network elements that can communicate with the terminal, so that the UE starts to establish a session.

[0161] In one implementation, the first network element triggers the terminal to establish the second session according to the first information, which may include: when determining that the first application is an edge application server (EAS) according to the first information, the first network element triggers the terminal to establish the second session.

[0162] Among them, determining that the first application is an edge application server based on the first information may include: determining that the address of the first application is the address of the edge application server based on the address information of the first application, or determining that the domain name corresponding to the first application is the domain name of the edge application server based on the domain name information corresponding to the first application.

[0163] In one implementation, the first network element may trigger the terminal to establish the second session by sending an indication message (hereinafter referred to as the third indication message) to the terminal. For example, in a 5G network, Figure 5 As shown, S203 may include S305 and S306:

[0164] S305. The SMF determines to trigger the terminal to establish a second session based on the first information.

[0165] For example, if the SMF determines, based on the first information, that the first application is an edge application server, it determines to trigger the terminal to establish a second session.

[0166] S306. After determining that the terminal is triggered to establish the second session, the SMF sends a Namf_Communication_N1N2MessageTransfer to the AMF.

[0167] In this way, after receiving Namf_Communication_N1N2MessageTransfer, AMF sends the N1 SM container (N1 SM Container) included in Namf_Communication_N1N2MessageTransfer to the terminal (ie Figure 5 S307 in the N1 SM Container triggers the terminal to establish a PDU session based on the N1 SM Container. The N1 SM Container includes: a PDU Session Modification Command. The PDU Session Modification Command includes: a Cause value and a PDU Session Address Lifetime value. The Cause value indicates that the UE should immediately re-initiate a PDU session connection with the same DN. The PDU Session Address Lifetime value indicates how long the network will continue to retain the current PDU session (such as the first session). After the timeout, the SMF will initiate the PDU session release process.

[0168] In a case where the first network element can trigger the terminal to establish the second session by sending indication information (hereinafter referred to as third indication information) to the terminal, the method may further include:

[0169] S204. The terminal receives third indication information from the first network element.

[0170] The third indication information is used to indicate the establishment of a second session.

[0171] During actual implementation, the first network element may forward the third indication information to the terminal via a transmission interface between the first network element and the terminal.

[0172] Alternatively, the first network element may forward the third indication information to the terminal through other network elements in the network.

[0173] For example, in 5G networks, Figure 5As shown, Namf_Communication_N1N2MessageTransfer (i.e. Figure 5 Then AMF sends the N1 SM Container included in Namf_Communication_N1N2MessageTransfer to the terminal (i.e. Figure 5 Therefore, when the first network element is an SMF, the third indication information can be understood as the Cause value included in the N1 SM Container in the above example.

[0174] Therefore, if Figure 5 As shown, S204 may include: S307, the terminal receives the N1 SM Container from the AMF. S205, the terminal establishes a second session according to the third indication information.

[0175] For example, in a 5G network, after the terminal receives the N1 SM container, the terminal can initiate the establishment process of the second session according to the Cause value contained in the N1 SM container. Figure 5 As shown, S205 may include: S308, the terminal sends a PDU session establishment request (PDU session establishment request) to the AMF.

[0176] The PDU session establishment request carries the old PDU Session ID (identifier of the first session) and the new PDU Session ID (identifier of the second PDU session). After receiving the PDU session establishment request, the AMF can select the SMF serving the second PDU session to establish the second PDU session.

[0177] S206: When the second session is successfully established, the first network element sends first indication information to the second network element.

[0178] The first indication information is used to instruct the second network element to send second information to the terminal. The second information includes address information of the first application.

[0179] The second information may include DNS response information. Specifically, the second information may be a DNS response message from a DNS server. For example, the second information may be Figure 5In S303, after EASDF receives the DNS query request from UPF, EASDF receives the DNS response message from the DNS server.

[0180] It should be noted that in some scenarios, the second information may also include the domain name information corresponding to the first application. For ease of description, the following description primarily uses the example of the second information including the address information of the first application to illustrate the solution. It is readily understood that when the second information also includes the domain name information corresponding to the first application, the various execution steps of the method provided in the embodiments of this application can be implemented based on the same principles to achieve similar technical effects.

[0181] Specifically, in the 5G network, Figure 5 As shown, S206 may include: S309, when the second session is successfully established, SMF sends the above-mentioned first indication information to EASDF.

[0182] S207: When the terminal receives the second information from the second network element, the terminal transmits the data message of the first application through the second session.

[0183] For example, in 5G networks, Figure 5 As shown, after the terminal receives the DNS response message from the EASDF in S310, S207 may include: S311, when the terminal receives the DNS response message from the EASDF, the terminal transmits the data packet of the first application through the second session. The DNS response message carries the address information (such as the IP address) of the first application.

[0184] In one implementation, before S207, the method provided in the embodiment of the present application may further include: the terminal sending terminal capability information to the first network element, wherein the terminal capability information is used to indicate that the terminal has the ability to transmit data packets of the first application through the second session using the address information of the first application requested through the first session.

[0185] In the method of S201-S207 described above in the embodiment of the present application, when a terminal requests the address information of an application through a first session, if a second session needs to be established to transmit data packets of the application, the second session is first established, and then the application address information is sent to the terminal after the second session is successfully established. This prevents the terminal from transmitting application data packets through the first PDU session.

[0186] In one implementation, in order to ensure that the second network element can save the first information until the second network element sends the first information to the terminal, as shown in FIG. Figure 6 As shown, the method further includes:

[0187] S208. The first network element sends second indication information to the second network element.

[0188] The second indication information is used to instruct the second network element to cache the second information.

[0189] In the above implementation method, after receiving the first information from the second network element, the first network element also sends a second indication information to the second network element through the first network element, instructing the second network element to cache the second information, so that the second network element can save the second information until the second session is successfully established, and then send the second information to the terminal.

[0190] It should be noted that in Figure 6 In the method flow chart shown, S208 is executed between S202 and S203. In the specific implementation process, S208 can also be executed in any time period before S206. In other words, in the embodiment of the present application, there is no restriction on the timing of S208.

[0191] In addition, the method provided in the embodiment of the present application further provides the following two implementations for enabling the first network element to determine that the second session is successfully established:

[0192] In a first implementation, it is considered that the first network element can determine whether the second session is successfully established by sending subscription information to the network element that can determine whether the second session is successfully established, so that the first network element can determine whether the second session is successfully established. Figure 7 As shown, the method may further include:

[0193] S209: The first network element sends subscription information to the third network element.

[0194] The subscription information is used to instruct the third network element to send subscription notification information to the first network element after determining that the second session is successfully established. In some application scenarios, subscription information can also be called subscription event. In the embodiment of the present application, there is no restriction on the name of subscription information.

[0195] The third network element may be one of various network elements in the network that can determine that the second session is successfully established. For example, in a 5G network, the third network element may be an AMF, or the third network element may be a UDM.

[0196] In one possible design, the first network element may be SMF, the third network element may be AMF, and SMF may add subscription information to Namf_Communication_N1N2MessageTransfer, which is used by SMF to subscribe to AMF: when the second session is successfully established, subscription notification information is sent to SMF. For example, Figure 8 As shown:

[0197] S209 may include Figure 8 In S406: SMF sends Namf_Communication_N1N2MessageTransfer to AMF, where Namf_Communication_N1N2MessageTransfer carries subscription information. In addition, Namf_Communication_N1N2MessageTransfer may also include: PDU Session ID and N1 SMContainer. The content and function of PDU Session ID and N1 SM Container can be referred to the above description and will not be repeated here. The subscription information is used to instruct AMF to send subscription notification information to SMF after determining that the second session is successfully established. For example, Figure 8 In S409, AMF sends subscription notification information to SMF.

[0198] In another possible design, the first network element may be an SMF, and the third network element may be an UDM. Figure 9 As shown:

[0199] S209 may include: S506, SMF-1 sends Nudm_EventExposure_Subscribe to UDM, where Nudm_EventExposure_Subscribe carries the identifier of the first session (also called old PDU session ID) and subscription information.

[0200] The subscription information is used by SMF-1 to subscribe to the UDM: when the UE successfully establishes a second session associated with the first session, it sends a subscription notification to the SMF-1 network element. The SMF-1 network element can be understood as the SMF corresponding to the first session, and the SMF-2 network element can be understood as the SMF corresponding to the second session.

[0201] Specifically, such as Figure 9 As shown, after AMF receives the PDU session establishment request (PDU session establishment request) sent by the terminal (i.e. Figure 9 After S509), AMF selects SMF-2 to serve the second session according to the PDU session establishment request, and sends a session establishment request message to SMF-2, wherein the session establishment request message may carry the identifier of the first session and the identifier of the second session (i.e. Figure 9Then, after receiving the session establishment request message from AMF, SMF-2 sends Nudm_UECM_Registration to UDM, where Nudm_UECM_Registration can carry the identifier of the first session and the identifier of the second session (i.e. Figure 9 Then, after receiving Nudm_UECM_Registration from SMF-2, UDM can determine that the second session is successfully established, and then send subscription notification information to SMF-1 (ie Figure 9 (S512).

[0202] In addition, if Figure 7 As shown, S206 may specifically include:

[0203] S206a. After receiving the subscription notification information, the first network element sends first indication information to the second network element.

[0204] For example, in Figure 8 In the example, S206a may include: S410, after receiving the subscription notification information, the SMF sends the first indication information to the EASDF. Figure 9 In S206a, S513 may include: after receiving the subscription notification information, the SMF sends the first indication information to the EASDF.

[0205] In addition, it should be noted that Figure 8 and Figure 9 For the implementation process of other steps in Figure 5 The corresponding description will not be repeated here.

[0206] In the second implementation, it is considered that the first network element can be made to serve the second session so that the first network element can determine whether the second session is successfully established, such as Figure 10 As shown, in the method, S203 may include:

[0207] S203a. The first network element sends fifth indication information to the fourth network element according to the first information.

[0208] The fifth indication information is used to instruct the fourth network element to select the first network element to serve the second session. It can also be understood that the fifth indication information is used to indicate that the second session is served by the first network element.

[0209] For example, Figure 11 As shown, when the first network element is SMF, the third network element is UDM, and the fourth network element is AMF, S203a may include: S606.

[0210] In S606, the Namf_Communication_N1N2MessageTransfer message sent by the SMF to the AMF carries the fifth indication information. The fifth indication information is used to instruct the AMF to select the same SMF (i.e., the first network element) as the first session for the currently established session (i.e., the second session). In addition, the Namf_Communication_N1N2MessageTransfer message may also include: a PDU Session ID and an N1 SM Container. The contents and functions of the PDU Session ID and the N1 SM Container can be referred to the above description and will not be repeated here.

[0211] Specifically, such as Figure 11 As shown, after AMF receives the PDU session establishment request (PDU session establishment request) sent by the terminal (i.e. Figure 11 After S608), AMF selects SMF (i.e., the first network element) to serve the second session according to the PDU session establishment request and the fifth indication information, and sends a session establishment request message to SMF, wherein the session establishment request message may carry the identifier of the first session and the identifier of the second session (i.e., Figure 11 Then, after receiving the session establishment request message from the AMF, the SMF may determine that the second session is successfully established.

[0212] in addition, Figure 11 For other steps in the Figure 5 The corresponding description will not be repeated here.

[0213] Regarding the aforementioned method 2, the communication method provided in the embodiment of the present application is as follows: Figure 12 As shown, this may include:

[0214] S701: Establish a first session for a terminal.

[0215] The first session may be a PDU session. In order to establish the second session before the first session is released, the first session may be a PDU session of SSC mode 3.

[0216] The first session is used to request the address information of the first application. For example, after the first session is established, the terminal sends a DNS query message through the first session. The DNS query message carries the domain name information corresponding to the first application. The DNS query message is used to request the address information of the first application. Exemplarily, the address information of the first application can be an IP address, and the domain name information corresponding to the first application can be a fully qualified domain name (FQDN).

[0217] On the one hand, from the perspective of a network element for session management in the network (hereinafter referred to as a first network element), S701 may include: the first network element establishes a first session for the terminal.

[0218] For example, the first network element may be an SMF in a 5G network, and S701 may be understood as: SMF establishes a first session for the terminal, that is, SMF establishes a first session for the terminal through the steps performed by SMF in the PDU session establishment process.

[0219] Exemplarily, in a 5G network, the PDU session establishment process may include: 1. The terminal initiates the PDU session establishment process. Specifically, the terminal carries parameters such as the PDU session identifier, SSC mode, single network slice selection assistance information (S-NSSAI) and data network name (DNN) and sends them to the AMF. 2. The AMF selects the SMF based on the S-NSSAI and DNN, and sends the AMF network element identifier, the terminal's permanent identifier, the terminal's location information, the PDU session identifier, S-NSSAI and DNN and other parameters to the SMF network element. Among them, the terminal's location information may include the terminal's tracking area identity (TAI). 3. The SMF selects the anchor point UPF and EASDF for the PDU session, and sends configuration information to the EASDF network element. The configuration information is used by the EASDF to monitor the DNS response message. 4. The terminal obtains the IP address of the EASDF (for example, the terminal obtains the IP address of the EASDF from the PDU session reception message), and uses the IP address as the destination address of the DNS query message subsequently initiated through the first session.

[0220] From the perspective of the SMF, S701 may include the following steps: the SMF selects the anchor points UPF and EASDF for the PDU session, and sends configuration information to the EASDF network element, wherein the configuration information is used by the EASDF to monitor the DNS response message.

[0221] On the other hand, from the perspective of the terminal, S701 may include: the terminal establishes the first session. For example, in a 5G network, S701 may include: the terminal establishes the first session through the steps performed by the terminal in the PDU session establishment process. Specifically, taking the above-mentioned PDU session establishment process in the 5G network as an example, S701 may include: the terminal initiates the PDU session establishment process, and the terminal obtains the IP address of the EASDF, and the terminal uses the IP address as the destination address of the DNS query message subsequently initiated through the first session.

[0222] S702: The first network element receives first information from the second network element.

[0223] The first information includes the address information of the first application or the domain name information corresponding to the first application. For example, the address information of the first application may be an IP address, and the domain name information corresponding to the first application may be a fully qualified domain name (FQDN).

[0224] It should be noted that the first information referred to in the embodiments of the present application includes the address information of the first application or the domain name information corresponding to the first application, which can be understood as: the first information includes at least one of the address information of the first application or the domain name information corresponding to the first application. In other words, during the implementation of the embodiments of the present application, the first information may include the address information of the first application, or the first information may include the domain name information corresponding to the first application, or the first information may include the address information of the first application and the domain name information corresponding to the first application. This embodiment of the present application is not limited to this.

[0225] The second network element may be a network element that receives a DNS query message from the terminal and a DNS response message from the DNS server. For example, the second network element may be an EASDF network element in a 5G network.

[0226] In conjunction with the description of step S701, since the terminal obtains the IP address of the EASDF during the session establishment process, when the terminal needs to obtain the address information of the first application, the terminal can send a DNS query message to the EASDF, where the destination address of the DNS query message is the IP address of the EASDF, and the DNS query message carries the FQDN corresponding to the first application. The EASDF sends the DNS query message to the DNS server and receives a DNS response message from the DNS server, where the DNS response message includes the address information of the first application and the domain name information corresponding to the first application.

[0227] That is, after the first session is successfully established, the second network element can send the address information of the first application requested by the terminal through the first session or the domain name information corresponding to the address information to the first network element, so that the first network element can determine whether to trigger the terminal to establish a new session to transmit the data message of the first application. The first network element triggering the terminal to establish the second session can be understood as: the first network element uses a preset process, such as sending a message or instruction (such as the third instruction information below) to the terminal or other network elements capable of communicating with the terminal, so that the UE starts to establish a session.

[0228] For example, when the first network element is SMF and the second network element is EASDF, Figure 13 As shown, after establishing the first session for the terminal in S801, first, refer to Figure 13 In S802, the terminal can send a DNS query request (DNS query) to the UPF through the access network device according to business needs to initiate a DNS query for the first application, wherein the DNS query can carry the domain name corresponding to the first application, which can be a FQDN or other form of domain name. In addition, the destination address included in the DNS query is the IP address of the EASDF. Then, as Figure 13 In S803, UPF sends the DNS query request to EASDF. Then, after EASDF sends the DNS query request to the DNS server, it can receive the DNS response message from the DNS server and monitor the FQDN or IP address carried in the DNS response message according to the configuration information sent by SMF. Figure 13 In S804, the EASDF may send a first message to the SMF, where the first message carries the FQDN or IP address in the DNS response message.

[0229] That is to say, when this method is applied in a 5G network, S702 can be understood as: Figure 13 S804 in.

[0230] The contents of S701 and S702 above can refer to the corresponding descriptions of S201 and S202 above, and will not be repeated here.

[0231] S703. The first network element sends fourth indication information to the terminal according to the first information.

[0232] In other words, S703 can also be understood as: the terminal receives the fourth indication information from the first network element.

[0233] The fourth indication information includes at least one of address information of the first application (hereinafter referred to as first address information), domain name information corresponding to the first application (hereinafter referred to as first domain name information), or identification information of the first application. The fourth indication information is used to instruct the terminal to transmit data packets of the first application through the second session.

[0234] Specifically, after the first network element determines that it is necessary to send fourth indication information to the terminal based on the first information (that is, the first network element determines that it is necessary to instruct the terminal to transmit the data packet of the first application through the second session), the first network element can determine the content included in the fourth indication information based on the first information. For example, if the first information contains the address information of the first application, the first network element can use the first address information as the fourth information. For another example, when the first network element can determine the identification information of the first application based on the domain name information corresponding to the first application (for example, the correspondence between the domain name information corresponding to the first application and the identification information of the first application is configured on the first network element), if the first information contains the domain name information corresponding to the first application, the first network element can use the domain name information corresponding to the first application or the identification information of the first application as the fourth information. Then, the fourth indication information is sent to the terminal.

[0235] For example, in Figure 13 In the case where SMF receives the first message from EASDF ( Figure 13 After S804), the SMF may first determine whether to trigger the terminal to establish a second session according to the first information, so that the terminal can transmit the data message of the first application through the second session ( Figure 13 In S805), the process in which the SMF determines whether to trigger the terminal to establish a second session can refer to the corresponding description of S203 above.

[0236] Afterwards, after the SMF determines that the terminal is triggered to establish a second session, the SMF sends a Namf_Communication_N1N2MessageTransfer( Figure 13S806 in the above text). For example, Namf_Communication_N1N2MessageTransfer specifically carries PDU Session ID and N1 SM container, wherein N1 SMcontainer includes: PDU Session Modification Command. PDU Session ModificationCommand may include a Cause value and fourth indication information. The fourth indication information includes the FQDN or IP address of the first application (equivalent to the first domain name information and the first address information above), and the fourth indication information is used to instruct the terminal to send a receipt information to the SMF after receiving the FQDN or IP address included in the PDU Session Modification Command. For example, the receipt information may be PDU Session Modification Command ACK. Afterwards, AMF sends the N1 SM container to the terminal ( Figure 13 S807). Thus, the fourth indication information is sent to the terminal.

[0237] In addition, after receiving the N1 SM container, the terminal can initiate the establishment process of the second session according to the Cause value contained in the N1 SM container. At the same time, the terminal learns to transmit the data message of the first application through the second session according to the fourth indication information contained in the N1 SM container.

[0238] S704: When the terminal receives the first address information or the first domain name information corresponding to the first address information from the second network element, the terminal transmits the data message of the first application through the second session.

[0239] It should be noted that, during specific implementations, there may be no restriction on the timing between the terminal receiving the first address information or the first domain name information corresponding to the first address information from the second network element and the successful establishment of the second session. That is, in some scenarios, the second network element may first send the first address information or the first domain name information corresponding to the first address information to the terminal, and then establish the second session after the terminal receives the first address information. Alternatively, the second session may be established first, and after the second session is successfully established, the second network element may then send the first address information or the first domain name information corresponding to the first address information to the terminal.

[0240] Specifically, after the terminal receives the fourth indication information, if the terminal first receives the first address information from the second network element or the first domain name information corresponding to the first address information, then according to the fourth indication information, the terminal will not transmit the data packet of the first application from the first session, but after the second session is successfully established, the terminal will transmit the data packet of the first application through the second session.

[0241] In one implementation, in order to ensure that the terminal transmits the data message of the first application through the second session, such as Figure 12 As shown, the method further includes:

[0242] S705. After the terminal receives the fourth indication information, the first network element sends the first indication information to the second network element.

[0243] The first indication information is used to instruct the second network element to send second information to the terminal. The second information may include address information of the first application.

[0244] For example, the second information may include DNS response information. Specifically, the second information may be a DNS response message from a DNS server.

[0245] For example, the second information can be Figure 13 In S803, after EASDF receives the DNS query request from UPF, EASDF receives the DNS response message from the DNS server.

[0246] In some scenarios, the second information may also include domain name information corresponding to the first application.

[0247] In this implementation, after determining that the terminal has received the fourth indication information, the first network element then sends the first indication information to the second network element, instructing the second network element to send the second information to the terminal. This ensures that after receiving the DNSresponse message, the terminal can transmit the data packet of the first application through the second session in accordance with the fourth indication information.

[0248] For example, in a 5G network, Figure 13 In the process, after receiving the receipt information sent by the terminal, SMF sends the first indication information ( Figure 13 Then, after receiving the first indication information, the EASDF sends a DNS response message to the terminal, referring to the FQDN or IP address of the first application carried in the DNS response message ( Figure 13 In this way, since the terminal receives the fourth indication information first and then receives the FQDN or IP address of the first application, it can be ensured that the terminal transmits the data message of the first application through the second session according to the fourth indication information.

[0249] In one implementation, in order to ensure that the second network element can save the first information until the second network element sends the first information to the terminal, as shown in FIG. Figure 12 As shown, the method further includes:

[0250] S706. The first network element sends second indication information to the second network element.

[0251] The second indication information is used to instruct the second network element to cache the second information.

[0252] In the above implementation method, after receiving the first information from the second network element, the first network element also sends a second indication information to the second network element through the first network element, instructing the second network element to cache the second information, so that the second network element can save the second information until the second session is successfully established, and then send the second information to the terminal.

[0253] In the above embodiment of the present application, after establishing a first session for the terminal to request the address information of the first application, if the first network element receives the first information from the second network element (including the address information of the first application or the domain name information corresponding to the address information), the first network element can send a fourth indication information to the terminal based on the first information, so that the terminal transmits the data packet of the first application by establishing a second session according to the fourth indication information.

[0254] It is understood that in the embodiments of the present application, each network element in the terminal and / or network may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples. In the embodiments of the present application, other operations or variations of various operations may also be performed. In addition, the steps may be performed in a different order than those presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed. The embodiments provided in this application may be associated with each other and may reference or quote each other.

[0255] The above embodiments mainly introduce the solutions provided by the embodiments of the present application from the perspective of interaction between devices. It should be understood that in order to realize the corresponding functions, the above-mentioned terminals and each network element in the network include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the units of the various examples described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0256] In the embodiment of the present application, the functional modules of the device (including the terminal and each network element in the network) can be divided according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. Optionally, the division of modules in the embodiment of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0257] like Figure 14 As shown, it is a schematic diagram of the composition of a communication device 90 provided in an embodiment of the present application. The communication device 90 can be a chip or a system on a chip. The communication device 90 can implement the functions of the first network element involved in the above embodiment. As an implementation method, the communication device 90 includes: a processing unit 901 and a communication unit 902. Among them: the processing unit 901 is used to enable the first network element to execute Figure 4 S201, S203 and Figure 10 S203a. The communication unit 902 is used to enable the first network element to execute Figure 4 S202, S204, S206 and Figure 6 S208, Figure 7 Alternatively, the processing unit 901 is configured to cause the first network element to execute Figure 12 S701. The communication unit 902 is used to enable the first network element to execute Figure 12 Among S702, S703, S705 and S706.

[0258] As an example, combining Figure 3 The communication device shown, Figure 14 The processing unit 901 in the Figure 3 The processor 101 is used to implement Figure 14 The communication unit 902 in the Figure 3 This is achieved by the communication interface 104 in .

[0259] It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here. The communication device 90 provided in the embodiment of the present application is used to perform the function of the first network element in the above communication method, thereby achieving the same effect as the above communication method. As an option but not a requirement, when necessary, the communication device 90 may also include a processing module or a control module for supporting the above processing unit 901 and / or the communication unit 902 to complete the corresponding functions.

[0260] An embodiment of the present application also provides a computer-readable storage medium, in which computer instructions are stored; when the computer-readable storage medium runs on a communication device, the communication device implements the function of the first network element in the method provided in the embodiment of the present application.

[0261] An embodiment of the present application also provides a computer program product containing computer instructions, which, when executed on a communication device, enables the communication device to implement the function of the first network element in the method provided in an embodiment of the present application.

[0262] An embodiment of the present application provides a chip including a processor. When the processor executes instructions, the chip implements the functions of the first network element in the method provided in the embodiment of the present application. The instructions may be from a memory within the chip or from a memory external to the chip. Optionally, the chip also includes input and output circuits serving as a communication interface.

[0263] like Figure 15 As shown in FIG, a schematic diagram of the composition of a communication device 100 provided in an embodiment of the present application. The communication device 100 can be a chip or a system on a chip. The communication device 100 can implement the functions of the terminal involved in the above embodiment. As an implementation method, the communication device 100 includes: a processing unit 1001 and a communication unit 1002. Among them: the processing unit 1001 is used to enable the terminal to execute Figure 4 S201, S205 and S207. The communication unit 1002 is used to enable the first network element to execute Figure 4 Alternatively, the processing unit 1001 is configured to cause the first network element to execute Figure 12 S701 and S704. The communication unit 1002 is used to enable the first network element to execute Figure 12 Medium S703.

[0264] As an example, combining Figure 3 The communication device shown, Figure 15 The processing unit 1001 in Figure 3 The processor 101 is used to implement Figure 15 The communication unit 1002 in the Figure 3 This is achieved by the communication interface 104 in .

[0265] It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here. The communication device 100 provided in the embodiment of the present application is used to perform the functions of the terminal in the above communication method, thereby achieving the same effect as the above communication method. As an option but not a requirement, when necessary, the communication device 100 may further include a processing module or a control module for supporting the above processing unit 1001 and / or the communication unit 1002 to perform the corresponding functions.

[0266] An embodiment of the present application also provides a computer-readable storage medium, in which computer instructions are stored; when the computer-readable storage medium runs on a communication device, the communication device implements the functions of the terminal in the method provided in the embodiment of the present application.

[0267] The embodiment of the present application also provides a computer program product containing computer instructions, which, when executed on a communication device, enables the communication device to implement the functions of the terminal in the method provided in the embodiment of the present application.

[0268] An embodiment of the present application provides a chip including a processor. When the processor executes instructions, the chip implements the terminal functions of the method provided in the embodiment of the present application. The instructions may be from a memory within the chip or from a memory external to the chip. Optionally, the chip also includes input and output circuits serving as a communication interface.

[0269] The functions, actions, operations, steps, etc. in the above embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using a software program, they can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can 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 can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that can be integrated with the medium. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0270] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, the present application is intended to include such modifications and variations as fall within the scope of the claims of the present application and their equivalents.

Claims

1. A communication method, characterized in that: Applied to a first network element or a chip in the first network element, the method includes: Establishing a first session for the terminal, where the first session is used for the terminal to obtain address information of the first application through a domain name system DNS query request, and the first session is a PDU session; receiving first information from a second network element, where the first information includes the address information of the first application or domain name information corresponding to the first application; triggering the terminal to establish a second session according to the first information, where the second session is used to transmit data packets of the first application, and the second session is a PDU session; When the second session is successfully established, first indication information is sent to the second network element, where the first indication information is used to instruct the second network element to send second information to the terminal, where the second information includes the address information of the first application.

2. The method according to claim 1, characterized in that The method further comprises: Sending subscription information to a third network element, where the subscription information is used to instruct the third network element to send subscription notification information to the first network element after determining that the second session is successfully established; When the second session is successfully established, sending first indication information to the second network element includes: After receiving the subscription notification information, the first indication information is sent to the second network element.

3. The method according to claim 2, characterized in that The third network element is an access and mobility management function AMF network element or a unified data management function UDM network element.

4. The method according to claim 1, wherein Triggering the terminal to establish a second session according to the first information includes: Send fifth indication information to a fourth network element according to the first information, where the fifth indication information is used to instruct the fourth network element to select the first network element to serve the second session.

5. The method according to any one of claims 1 to 4, characterized in that The first network element is a session management function SMF network element.

6. The method according to any one of claims 1 to 4, characterized in that The method further comprises: Send second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

7. The method according to any one of claims 1 to 4, characterized in that The second information includes Domain Name System (DNS) response information.

8. The method according to any one of claims 1 to 4, characterized in that The first session and the second session are sessions and service continuity mode SSC mode 3 sessions.

9. A communication method, characterized in that: The method applied to a terminal or a chip in a terminal includes: Establishing a first session, where the first session is used by the terminal to obtain address information of the first application through a domain name system DNS query request, and the first session is a PDU session; receiving third indication information from the first network element, where the third indication information is used to instruct establishment of a second session, where the second session is used to serve the first application, and the second session is a PDU session; Establishing the second session according to the third indication information; When receiving second information from a second network element, the second information includes the address information of the first application, and transmitting a data packet of the first application through the second session.

10. The method according to claim 9, characterized in that The second information includes domain name system response DNSresponse information.

11. The method according to any one of claims 9 to 10, characterized in that: The first session and the second session are sessions and service continuity mode SSC mode 3 sessions.

12. A communication method, characterized in that: Applied to a first network element or a chip in the first network element, the method includes: Establishing a first session for the terminal, where the first session is used for the terminal to obtain address information of the first application through a domain name system DNS query request, and the first session is a PDU session; receiving first information from a second network element, where the first information includes the address information of the first application or domain name information corresponding to the first application; According to the first information, fourth indication information is sent to the terminal, where the fourth indication information includes at least one of the address information of the first application, the domain name information corresponding to the first application, or the identification information of the first application. The fourth indication information is used to instruct the terminal to transmit the data packet of the first application through the second session, where the second session is a PDU session.

13. The method according to claim 12, characterized in that The method further comprises: After receiving the fourth indication information, the terminal sends first indication information to the second network element, where the first indication information is used to instruct the second network element to send second information to the terminal; the second information includes the address information of the first application.

14. The method according to claim 13, characterized in that The method further comprises: Send second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

15. The method according to claim 13 or 14, characterized in that The second information is domain name system response DNSresponse information.

16. The method according to any one of claims 12 to 14, characterized in that: The first session and the second session are sessions and service continuity mode SSC mode 3 sessions.

17. A communication method, characterized in that: The method applied to a terminal or a chip in a terminal includes: Establishing a first session, where the first session is used by the terminal to obtain address information of the first application through a domain name system DNS query request, and the first session is a PDU session; receiving fourth indication information from the first network element, the fourth indication information including at least one of the address information of the first application, domain name information corresponding to the first application, or identification information of the first application, the fourth indication information being used to instruct the terminal to transmit a data packet of the first application through the second session; The terminal receives the address information or domain name information corresponding to the first application from the second network element, and transmits the data message of the first application through the second session, where the second session is a PDU session.

18. The method according to claim 17, characterized in that The first session and the second session are sessions and service continuity mode SSC mode 3 sessions.

19. A communication method, characterized in that: include: The first network element establishes a first session for the terminal, where the first session is used by the terminal to obtain address information of the first application through a domain name system DNS query request, and the first session is a PDU session; The first network element receives first information from the second network element, where the first information includes the address information of the first application or domain name information corresponding to the first application; The first network element triggers the terminal to establish a second session according to the first information, where the second session is used to serve the first application and is a PDU session; The terminal receives third indication information from the first network element, where the third indication information is used to instruct establishment of the second session; The terminal establishes the second session according to the third indication information; When the second session is successfully established, the first network element sends first indication information to the second network element, where the first indication information is used to instruct the second network element to send second information to the terminal, where the second information includes the address information of the first application; When the terminal receives second information from the second network element, where the second information includes the address information of the first application, the terminal transmits a data packet of the first application through the second session.

20. The method according to claim 19, characterized in that The method further comprises: The first network element sends subscription information to the third network element, where the subscription information is used to instruct the third network element to send subscription notification information to the first network element after determining that the second session is successfully established; When the second session is successfully established, the first network element sends first indication information to the second network element, including: After receiving the subscription notification information, the first network element sends the first indication information to the second network element.

21. The method according to claim 20, characterized in that The third network element is an access and mobility management function AMF network element or a unified data management function UDM network element.

22. The method according to claim 19, wherein The first network element triggering the terminal to establish a second session according to the first information includes: The first network element sends fifth indication information to a fourth network element according to the first information, where the fifth indication information is used to instruct the fourth network element to select the first network element to serve the second session.

23. The method according to any one of claims 19 to 22, characterized in that: The first network element is a session management function SMF network element.

24. The method according to any one of claims 19 to 22, characterized in that: The method further comprises: The first network element sends second indication information to the second network element; the second indication information is used to instruct the second network element to cache the second information.

25. The method according to any one of claims 19 to 22, characterized in that The second information is Domain Name System (DNS) response information.

26. The method according to any one of claims 19 to 22, characterized in that The method also includes: the first session and the second session are sessions and service continuity mode SSC mode 3 sessions.

27. A communication method, characterized in that: include: The first network element establishes a first session for the terminal, where the first session is used by the terminal to obtain address information of the first application through a domain name system DNS query request, and the first session is a PDU session; The first network element receives first information from the second network element, where the first information includes the address information of the first application or domain name information corresponding to the first application; The first network element sends, based on the first information, fourth indication information to the terminal, where the fourth indication information includes at least one of the address information of the first application, domain name information corresponding to the first application, or identification information of the first application, and the fourth indication information is used to instruct the terminal to transmit a data packet of the first application through a second session, where the second session is a PDU session; When the terminal receives the address information or the domain name information corresponding to the first application from the second network element, the terminal transmits the data message of the first application through the second session.

28. The method according to claim 27, characterized in that The method further comprises: After the terminal receives the fourth indication information, the first network element sends first indication information to the second network element, where the first indication information is used to instruct the second network element to send second information to the terminal, where the second information includes the address information of the first application.

29. The method according to claim 28, characterized in that The method further comprises: The first network element sends second indication information to the second network element, where the second indication information is used to instruct the second network element to cache the second information.

30. The method according to claim 28 or 29, characterized in that The second information is domain name system response DNSresponse information.

31. The method according to any one of claims 27 to 29, characterized in that The first session and the second session are sessions and service continuity mode SSC mode 3 sessions.

32. A communication device, characterized in that: include: At least one processor and a communication interface, when the processor executes computer program instructions, the communication device executes the method according to any one of claims 1 to 8, or the communication device executes the method according to any one of claims 12 to 16.

33. A communication device, characterized in that: include: At least one processor and a communication interface, when the processor executes computer program instructions, the communication device executes the method according to any one of claims 9 to 11, or the communication device executes the method according to claim 17 or 18.

34. A chip, characterized in that: The chip includes a processor, and when the processor executes computer program instructions, the chip performs any one of claims 1-8, or any one of claims 9-11, or any one of claims 12-16, or the method of claim 17 or 18.

35. A computer-readable storage medium, characterized in that include: computer software instructions; When the computer software instructions are executed in a communication device or a chip built into the communication device, the communication device executes the method of any one of claims 1 to 8, or any one of claims 9 to 11, or any one of claims 12 to 16, or claim 17 or 18.

36. A computer program product, characterized in that The computer program product comprises instructions, which, when run on a computer, causes the computer to perform the method of any one of claims 1 to 8, or any one of claims 9 to 11, or any one of claims 12 to 16, or claim 17 or 18.

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