A method and device for sending a domain name system request

Abstract

The present application provides a method and device for sending a domain name system request, which relates to the field of communication technology and can improve the efficiency of domain name system DNS resolution. The method includes: a terminal device determines the address of a first DNS server corresponding to a first application. The terminal device determines the first address of the terminal device based on the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server. Afterwards, the terminal device sends DNS request information. The DNS request information includes an identifier of the first application, the address of the first DNS server, and the first address of the terminal device.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a method and device for sending a domain name system request. Background Art

[0002] The packet data unit (PDU) session is connected to the data network (DN) through the packet data unit session anchor (PSA) network element, so that the terminal device and the application server (AS) in the DN can perform data transmission. The PSA network element is also connected to the domain name system (DNS) server. Among them, for the PSA network element, application server and DNS server deployed in the same data network, the DNS server receives the DNS request information from the PSA network element, resolves the domain name in the DNS request information, obtains the Internet protocol (IP) address of the application server, and then provides it to the terminal device through the PSA network element, so that the terminal device can realize data transmission with the application server according to the IP address of the above-mentioned application server.

[0003] In a multi-homing (MH) scenario, there are multiple PSA network elements for one PDU session. The user plane paths leading to different PSA network elements branch on the branch point (BP) device. One PSA network element corresponds to one DNS server, and different PSA network elements correspond to different DNS servers. In the MH scenario, the terminal device includes multiple addresses and corresponds to multiple PSA network elements. Among them, one address of the terminal device corresponds to one PSA network element, and different addresses of the terminal device correspond to different PSA network elements.

[0004] In the MH scenario, for a DNS request message, the source address in the DNS request message is an address of a terminal device and corresponds to a PSA network element, and the destination address in the DNS request message is the address of a DNS server. If there is no corresponding relationship between the PSA network element corresponding to the source address in a DNS request message and the DNS server corresponding to the destination address, that is, the PSA network element corresponding to the source address and the DNS server corresponding to the destination address cannot communicate, the phenomenon of "DNS resolution failure" occurs, resulting in low DNS resolution efficiency. Summary of the invention

[0005] The embodiments of the present application provide a method and device for sending a domain name system request, which can improve the efficiency of DNS resolution.

[0006] In order to achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a method for sending a domain name system request, and the execution subject of the method can be a terminal device or a chip applied to the terminal device. The following description is taken as an example that the execution subject is a terminal device. The method includes: the terminal device determines the address of a first domain name system DNS server corresponding to a first application. The terminal device determines the first address of the terminal device based on the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server. Afterwards, the terminal device sends a DNS request message. Among them, the DNS request information includes an identifier of the first application, the address of the first DNS server and the first address of the terminal device.

[0008] Since there is a corresponding relationship between the address of the first DNS server and the first address of the terminal device, and the first address of the terminal device corresponds to a PSA network element, that is, the first DNS server and the PSA network element corresponding to the first address of the terminal device can communicate with each other. Since the DNS request information sent by the terminal device includes the address of the first DNS server and the first address of the terminal device, the DNS request information can be transmitted to the first DNS server through the PSA network element corresponding to the terminal device, thereby improving the success rate of DNS resolution and reducing the phenomenon of "DNS resolution failure" caused by "no communication between the DNS server and the PSA network element" in the prior art.

[0009] In a possible design, the method for sending a domain name system request in an embodiment of the present application further includes: the terminal device receives the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server from the session management function SMF network element. For example, "the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server" can be carried in a routing rule and transmitted to the terminal device. In other words, the SMF network element can provide the terminal device with the information of "the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server".

[0010] In one possible design, the terminal device determines the address of the first DNS server corresponding to the first application, including: the terminal device receives the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application from the SMF network element. For example, "the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application" can be carried in a routing rule and transmitted to the terminal device. Afterwards, the terminal device determines the address of the first DNS server based on the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application.

[0011] In this way, when the SMF network element provides the terminal device with "the identification of the first application and the address of the DNS server corresponding to the identification of the first application", the terminal device can determine the address of the first DNS server based on the information provided by the SMF network element.

[0012] In a possible design, the identifier of the first application corresponds to multiple DNS servers. The terminal device determines the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application, including: the terminal device determines the first DNS server that meets the preset policy from the multiple DNS servers. The preset policy includes at least one of the following: the priority of the first DNS server meets the priority condition among the priorities of the multiple DNS servers; the distance between the first DNS server and the terminal device meets the interval distance condition.

[0013] In this way, when the identifier of the first application corresponds to multiple DNS servers, the terminal device can determine a DNS server from the multiple DNS servers as the first DNS server according to the preconfigured preset policy, and then determine the address of the first DNS server.

[0014] In the second aspect, an embodiment of the present application provides a method for sending a domain name system request, and the execution subject of the method can be a branch point BP device, or a chip applied to the BP device. The following description is taken as an example that the execution subject is a BP device. The method includes: the BP device receives a domain name system DNS request information from a terminal device, and then the BP device updates at least one of the source address and the destination address in the DNS request information to obtain an updated DNS request information. Among them, the source address in the updated DNS request information is the first address of the terminal device, and the destination address in the updated DNS request information is the address of the first DNS server. The BP device sends the updated DNS request information to the first packet data unit session anchor PSA network element according to the source address in the updated DNS request information. Among them, the first PSA network element corresponds to the first address of the terminal device, and the destination address in the updated DNS request information is used by the first PSA network element to send the updated DNS request information to the first DNS server, so as to enable the first DNS server to resolve the updated DNS request information.

[0015] Since the source address in the updated DNS request information is the first address of the terminal device, and the destination address in the updated DNS request information is the address of the first DNS server, the first PSA network element corresponding to the first address of the terminal device can communicate with the first DNS server, so that the updated DNS request information can be transmitted to the first DNS server through the first PSA network element, thereby improving the success rate of DNS resolution and reducing the phenomenon of "DNS resolution failure" caused by "no communication between the DNS server and the PSA network element" in the prior art.

[0016] In one possible design, the BP device updates at least one of the source address and the destination address in the DNS request information, including: the BP device updates at least one of the source address and the destination address in the DNS request information according to the identifier of the first application in the DNS request information, or the BP device updates the destination address in the DNS request information according to the source address in the DNS request information, or the BP device updates the source address in the DNS request information according to the destination address in the DNS request information.

[0017] That is to say, in the process of updating the DNS request information, the BP device can update at least one of the source address and the destination address in the DNS request information based on the identifier of the first application in the DNS request information, or the source address of the DNS request information, or the destination address of the DNS request information to obtain the updated DNS request information.

[0018] In a possible design, the BP device updates at least one of the source address and the destination address in the DNS request information according to the identifier of the first application in the DNS request information, including: the BP device determines the address of the first DNS server corresponding to the identifier of the first application, and then the BP device updates the destination address in the DNS request information to the address of the first DNS server. The BP device determines the first address of the terminal device according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server, and then the BP device sets the source address in the DNS request information to the first address of the terminal device.

[0019] In this way, the BP device can update the source address and the destination address in the DNS request information based on the identifier of the first application to obtain the updated DNS request information.

[0020] In one possible design, the BP device determines the address of the first DNS server corresponding to the identifier of the first application, including: the BP device receives the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application from the session management function SMF network element, and then, the BP device determines the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application.

[0021] In this way, when the SMF network element provides the BP device with "the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application", the BP device can determine the address of the first DNS server based on the information provided by the SMF network element.

[0022] In a possible design, the BP device updates the source address in the DNS request information according to the destination address in the DNS request information, including: if the destination address in the DNS request information is the address of the first DNS server, the BP device determines the first address of the terminal device according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server. Afterwards, the BP device updates the source address in the DNS request information to the first address of the terminal device.

[0023] That is, after receiving the DNS request information, the BP device replaces the source address in the DNS request information with the destination address in the DNS request information to ensure that the PSA network element corresponding to the source address in the updated DNS request information can communicate with the first DNS server.

[0024] In a possible design, the method for sending a domain name system request in an embodiment of the present application also includes: the BP device receives the address of the first DNS server from the SMF network element and the address of the terminal device corresponding to the address of the first DNS server.

[0025] That is to say, the SMF network element can provide the BP device with the information of "the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server".

[0026] In a possible design, the BP device updates the destination address in the DNS request information according to the source address in the DNS request information, including: if the source address in the DNS request information is the first address of the terminal device, the BP device determines the address of the first DNS server according to the first address of the terminal device and the address of the DNS server corresponding to the first address of the terminal device. Afterwards, the BP device updates the destination address in the DNS request information to the address of the first DNS server.

[0027] That is, after receiving the DNS request information, the BP device replaces the destination address in the DNS request information based on the source address in the DNS request information to ensure that the PSA network element corresponding to the source address in the updated DNS request information can communicate with the first DNS server.

[0028] In a possible design, the method for sending a domain name system request in an embodiment of the present application also includes: the BP device receives a first address of a terminal device from an SMF network element and an address of a DNS server corresponding to the first address of the terminal device.

[0029] That is to say, the SMF network element can provide the BP device with the information of "the first address of the terminal device and the address of the DNS server corresponding to the first address of the terminal device".

[0030] In a possible design, the method for sending a domain name system request in an embodiment of the present application further includes: the BP device receives response information from the first PSA network element for the DNS request information. Afterwards, the BP device updates at least one of the source address and the destination address in the response information to obtain updated response information. The source address in the updated response information is the destination address of the DNS request information before the update, and the destination address in the updated response information is the source address of the DNS request information before the update. Then, the BP device sends the updated response information to the terminal device. The DNS request information includes an identifier of the first application, and the response information includes the Internet Protocol IP address of the application server corresponding to the first application.

[0031] Here, the updated response information includes the IP address of the application server corresponding to the first application, the destination address of the DNS request information before the update, and the source address of the DNS request information before the update. After the terminal device sends the DNS request information, it needs to monitor the response message carrying the source address and destination address of the DNS request information before the update. The BP device can replace at least one of the source address and the destination address in the response information to ensure that the terminal device can monitor the response message carrying the source address and the destination address of the DNS request information before the update.

[0032] In a third aspect, an embodiment of the present application provides a method for sending a domain name system request, and the execution subject of the method can be a branch point BP device or a chip applied to the BP device. The following description is taken as an example that the execution subject is a BP device. The method includes: the BP device receives a domain name system DNS request information from a terminal device, and then the BP device sends a DNS request information to a first packet data unit session anchor point PSA network element corresponding to the destination address according to the destination address in the DNS request information. Among them, the DNS request information is used by the first PSA network element to send the DNS request information to the first DNS server, so that the first DNS server can resolve the DNS request information.

[0033] Here, since the destination address of the DNS request information corresponds to the first PSA network element, the destination address of the DNS request information is the address of the first DNS server, and the first DNS server and the first PSA network element can communicate, it can reduce the phenomenon of "DNS resolution failure" caused by "inability to communicate between DNS server and PSA network element" in the prior art, and improve the success rate of DNS resolution.

[0034] In a fourth aspect, an embodiment of the present application provides a method for sending a domain name system request, and the execution subject of the method can be a first PSA network element, or a chip applied to the first PSA network element. The following description is taken as an example in which the execution subject is the first PSA network element. The method includes: the first PSA network element sends a DNS request message to a first domain name system DNS server. The DNS request information includes the address of the first DNS server and the second address of the terminal device corresponding to the second PSA network element. Afterwards, the first PSA network element receives response information for the DNS request information from the first DNS server. Then, the first PSA network element sends the response information to the branch point BP device according to the forwarding rule information. The forwarding rule information is used to instruct the first PSA network element to send a data packet with the destination address as the second address to the BP device, and the data packet includes the response information.

[0035] Here, the response information is the response information for the DNS request information. That is, in the process of the first DNS server feeding back the response information, after the first PSA network element receives the response information from the first DNS server, even if the destination address of the response information is the second address of the terminal device, corresponding to the second PSA network element, the first PSA network element can send the response information to the BP device according to the forwarding rule information, so that the response information can be provided to the terminal device through the BP device.

[0036] In a possible design, the method for sending a domain name system request in the embodiment of the present application further includes: the first PSA network element receives forwarding rule information from the session management function SMF network element. That is, the SMF network element provides the first PSA network element with forwarding rule information so that the first PSA network element forwards the response information according to the forwarding rule information.

[0037] In one possible design, the first PSA network element receives response information to the DNS request information from the first DNS server, including: the first PSA network element receives the response information to the DNS request information from the first DNS server through a tunnel between the first PSA network element and the first DNS server, wherein the DNS request information includes an identifier of the first application, and the response information includes an Internet Protocol IP address of an application server corresponding to the first application.

[0038] That is, the tunnel between the first PSA network element and the first DNS server can shield the destination address in the response information, so that the response information can be transmitted from the first DNS server to the first PSA network element.

[0039] In a fifth aspect, an embodiment of the present application provides a device for sending a domain name system request, the device for sending a domain name system request includes: a unit for executing each step in any of the above aspects. The device for sending a domain name system request can be a terminal device in the above first aspect or any possible design of the first aspect, or a chip that implements the function of the above terminal device. The device for sending a domain name system request includes a module, unit, or means corresponding to the above method, and the module, unit, or means can be implemented by hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0040] In a sixth aspect, an embodiment of the present application provides a device for sending a domain name system request, including a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute the method for sending a domain name system request provided in any of the above aspects. The processor includes one or more. The device for sending a domain name system request can be a terminal device in the above first aspect or any possible design of the first aspect, or a chip that implements the functions of the above terminal device.

[0041] In a seventh aspect, an embodiment of the present application provides a device for sending a domain name system request, comprising: a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the device for sending a domain name system request executes the method described in any of the above aspects. The device for sending a domain name system request can be a terminal device in the above first aspect or any possible design of the first aspect, or a chip that implements the functions of the above terminal device.

[0042] In an eighth aspect, an embodiment of the present application provides a device for sending a domain name system request, comprising: a processor; the processor is used to couple with a memory, and after reading instructions in the memory, execute the method as described in any of the above aspects according to the instructions. The device for sending a domain name system request can be a terminal device in the above first aspect or any possible design of the first aspect, or a chip that implements the functions of the above terminal device.

[0043] In a ninth aspect, an embodiment of the present application provides a device for sending a domain name system request, and the device for sending a domain name system request includes: a unit for executing each step in any of the above aspects. The device for sending a domain name system request can be the BP device in the above second aspect or any possible design of the second aspect, or a chip that implements the function of the above BP device; or, the device for sending a domain name system request can be the above third aspect or any possible design of the third aspect, or a chip that implements the function of the above BP device. The device for sending a domain name system request includes a module, unit, or means corresponding to the above method, and the module, unit, or means can be implemented by hardware, software, or by hardware executing the corresponding software implementation. The hardware or software includes one or more modules or units corresponding to the above functions.

[0044] In a tenth aspect, an embodiment of the present application provides a device for sending a domain name system request, including a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute the method for sending a domain name system request provided in any of the above aspects. The processor includes one or more. The device for sending a domain name system request can be the BP device in the second aspect or any possible design of the second aspect, or a chip that implements the function of the BP device; or, the device for sending a domain name system request can be the BP device in the third aspect or any possible design of the third aspect, or a chip that implements the function of the BP device.

[0045] In an eleventh aspect, an embodiment of the present application provides a device for sending a domain name system request, comprising: a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the device for sending a domain name system request executes the method described in any of the above aspects. The device for sending a domain name system request can be a BP device in the above second aspect or any possible design of the second aspect, or a chip that implements the function of the above BP device; or, the device for sending a domain name system request can be a BP device in the above third aspect or any possible design of the third aspect, or a chip that implements the function of the above BP device.

[0046] In a twelfth aspect, an embodiment of the present application provides a device for sending a domain name system request, comprising: a processor; the processor is used to couple with a memory, and after reading instructions in the memory, execute the method as described in any of the above aspects according to the instructions. The device for sending a domain name system request can be the BP device in the second aspect or any possible design of the second aspect, or a chip that implements the function of the BP device; or, the device for sending a domain name system request can be the BP device in the third aspect or any possible design of the third aspect, or a chip that implements the function of the BP device.

[0047] In a thirteenth aspect, an embodiment of the present application provides a device for sending a domain name system request, and the device for sending a domain name system request includes: a unit for executing each step in any of the above aspects. The device for sending a domain name system request can be the first PSA network element in the fourth aspect or any possible design of the fourth aspect, or a chip that implements the function of the first PSA network element. The device for sending a domain name system request includes a module, unit, or means corresponding to the above method, and the module, unit, or means can be implemented by hardware, software, or by hardware executing the corresponding software implementation. The hardware or software includes one or more modules or units corresponding to the above functions.

[0048] In a fourteenth aspect, an embodiment of the present application provides a device for sending a domain name system request, including a processor and an interface circuit, the processor is used to communicate with other devices through the interface circuit, and execute the method for sending a domain name system request provided in any of the above aspects. The processor includes one or more. The device for sending a domain name system request can be the first PSA network element in the fourth aspect or any possible design of the fourth aspect, or a chip that implements the function of the first PSA network element.

[0049] In a fifteenth aspect, an embodiment of the present application provides a device for sending a domain name system request, comprising: a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the device for sending a domain name system request executes the method described in any one of the above aspects. The device for sending a domain name system request can be the first PSA network element in the fourth aspect or any possible design of the fourth aspect, or a chip that implements the function of the first PSA network element.

[0050] In a sixteenth aspect, an embodiment of the present application provides a device for sending a domain name system request, comprising: a processor; the processor is used to couple with a memory, and after reading an instruction in the memory, execute the method as described in any of the above aspects according to the instruction. The device for sending a domain name system request can be the first PSA network element in the fourth aspect or any possible design of the fourth aspect, or a chip that implements the function of the first PSA network element.

[0051] In the seventeenth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores instructions. When the computer-readable storage medium is run on a computer, the computer can execute the method for sending a domain name system request of any one of the above aspects.

[0052] In an eighteenth aspect, an embodiment of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method for sending a domain name system request of any one of the above aspects.

[0053] In a nineteenth aspect, an embodiment of the present application provides a circuit system, the circuit system includes a processing circuit, and the processing circuit is configured to execute a method for sending a domain name system request as described in any one of the above aspects.

[0054] In the twentieth aspect, an embodiment of the present application provides a chip, the chip includes a processor, the processor is coupled to a memory, the memory stores program instructions, and when the program instructions stored in the memory are executed by the processor, the method for sending a domain name system request of any one of the above aspects is implemented.

[0055] In the twenty-first aspect, an embodiment of the present application provides a system for sending domain name system requests, wherein the system for sending domain name system requests includes the terminal device of any one of the first aspect, or includes the BP device of any one of the second aspect, or includes the BP device of any one of the third aspect and the first PSA network element of any one of the fourth aspect.

[0056] Among them, the technical effects brought about by any design in the fifth to twenty-first aspects can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A schematic diagram of a network architecture provided in an embodiment of the present application;

[0058] Figure 2 A schematic diagram of another network architecture provided in an embodiment of the present application;

[0059] Figure 3 A flowchart of a method for sending a domain name system request provided in an embodiment of the present application;

[0060] Figure 4 A flowchart of another method for sending a domain name system request provided in an embodiment of the present application;

[0061] Figure 5 A flowchart of another method for sending a domain name system request provided in an embodiment of the present application;

[0062] Figure 6 A flowchart of another method for sending a domain name system request provided in an embodiment of the present application;

[0063] Figure 7 A flowchart of another method for sending a domain name system request provided in an embodiment of the present application;

[0064] Figure 8 A flowchart of another method for sending a domain name system request provided in an embodiment of the present application;

[0065] Fig. 9 A schematic diagram of the structure of a device for sending a domain name system request provided in an embodiment of the present application;

[0066] Fig.10 A schematic diagram of the structure of another device for sending a domain name system request provided in an embodiment of the present application. DETAILED DESCRIPTION

[0067] The terms "first" and "second" in the specification and drawings of the present application are used to distinguish different objects, or to distinguish different treatments of the same object, rather than to describe the specific order of objects. In addition, the terms "including" and "having" and any variations thereof mentioned in the description of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally includes other steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. In the embodiment of the present application, "multiple" includes two or more. In the embodiment of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiment of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0068] First, the technical terms involved in the embodiments of the present application are introduced:

[0069] 1. Domain name resolution

[0070] DNS is a distributed database on the Internet that maps domain names to Internet Protocol (IP) addresses. It can map domain names to the IP addresses of application servers. Here, the process of mapping domain names to the IP addresses of application servers is called "domain name resolution".

[0071] A domain name, also known as a network domain, is a name of a computer or computer group on the Internet consisting of a string of names separated by dots, used to identify the electronic location or geographical location of the computer during data transmission. For example, a domain name can be www.123456.com.cn.

[0072] Among them, the domain name resolution device in the DNS is the DNS server. Here, the DNS server can resolve the domain name requested by the terminal device through the domain name resolution mechanism to obtain the IP address of the application server corresponding to the domain name. Optionally, the number of DNS servers can be multiple, and they are distributed in a hierarchical architecture. In the above-mentioned domain name resolution mechanism, the DNS resolves the domain name in turn through the DNS servers of the lower to higher levels until the IP address of the application server corresponding to the above-mentioned domain name is obtained. The domain name resolution mechanism is not described in detail in the embodiment of the present application.

[0073] Exemplarily, the process of a terminal device accessing a target domain name is as follows: after the terminal device obtains the target domain name, it sends a DNS request message carrying the target domain name to the DNS server. Accordingly, the DNS server receives the DNS request message from the terminal device. Afterwards, the DNS server resolves the IP address of the target application server corresponding to the above target domain name, and carries the IP address of the above target application server in the response message and sends it to the terminal device. Accordingly, the terminal device receives the response message from the DNS server, so that the terminal device obtains the IP address of the above target application server, and realizes data transmission with the above target application server based on the IP address. Here, "DNS request information" can also be described as a "request message" or a "domain name resolution request message". "Response message" can also be described as a "reply message", or a "DNS reply (response)", or a "domain name resolution response message", corresponding to the DNS request message.

[0074] 2. PDU Session

[0075] A PDU session is a connection between a terminal device and a data network, and is used to transmit data between the terminal device and the data network. A terminal device can connect to the same data network or different data networks through multiple PDU sessions.

[0076] 3. MH Mechanism

[0077] The terminal device can connect to the same data network through one or more PDU sessions served by different PSA network elements. Here, the PSA network element can be a user plane function (UPF) network element connected to the data network. PSA can also be recorded as the PDU session anchor UPF. In the embodiment of the present application, "UPF as PSA" is used as an example for illustrative explanation. In the MH mechanism, a PDU session is accessed to the data network through multiple PSA network elements. The user plane path leading to different PSA network elements is branched on the BP device. Here, the BP device can also be a UPF network element.

[0078] In the MH mechanism, the terminal device includes multiple addresses and corresponds to multiple PSA network elements, wherein one address of the terminal device corresponds to one PSA network element, and different addresses of the terminal device correspond to different PSA network elements.

[0079] In the process of the terminal device accessing the target domain name, the terminal device sends a DNS request message to the BP device. Correspondingly, the BP device receives the DNS request message from the terminal device. Among them, the DNS request message includes not only the target domain name, but also the source address and the destination address. Among them, the source address in the DNS request message is an address of the terminal device, and corresponds to a PSA network element. The destination address in the DNS request message is the address of a DNS server. If there is no corresponding relationship between the PSA network element corresponding to the source address in a DNS request message and the DNS server corresponding to the destination address, that is, the PSA network element corresponding to the source address and the DNS server corresponding to the destination address cannot communicate, then the phenomenon of "DNS resolution failure" occurs, resulting in low DNS resolution efficiency.

[0080] In view of this, an embodiment of the present application provides a method for sending a domain name system request. First, the system to which the method for sending a domain name system request in the embodiment of the present application is applicable is described. The system may be a communication system supporting fifth-generation (5G) mobile communication technology, such as NR access technology; or, the system may also be a communication system supporting multiple wireless technologies, such as a communication system supporting LTE technology and new radio (NR) access technology. In addition, the system may also be applicable to future-oriented communication technologies.

[0081] See also Figure 1 Taking the communication system supporting 5G mobile communication technology as an example, the network architecture of the system is introduced. The network elements in the 5G network architecture include terminal devices, access network (AN) equipment, access and mobility management function (AMF) network elements, session management function (SMF) network elements, PSA network elements, BP equipment and data network (DN). Figure 1 Only two PSA network elements are shown. Figure 1 It is only a schematic diagram and does not constitute a limitation on the applicable scenarios of the method for sending a domain name system request in the embodiment of the present application.

[0082] Among them, the terminal device, also known as user equipment (UE), terminal device, mobile station (MS), mobile terminal (MT), etc., is a device that provides voice / data connectivity to users, for example, a handheld device or vehicle-mounted device with wireless connection function. The terminal device can specifically be: a mobile phone, a tablet computer, a laptop computer, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, or a wireless terminal in smart home, a terminal device in a future 5G communication network or a communication network after 5G, etc., and the embodiments of the present application are not limited to this.

[0083] The access network device may also be a radio access network (RAN) device, which is a device deployed in a radio access network to provide wireless communication functions. Optionally, the RAN device involved in the embodiments of the present application includes, for example but not limited to, various forms of macro base stations, micro base stations (also called small stations), relay stations, transmission reception points (TRP), next generation network nodes (g Node B, gNB), evolved Node B (ng evolved Node B, ng-eNB) connected to the next generation core network, etc., and may also include RAN devices of non-third generation partnership project (3GPP) systems such as wireless local area network (WLAN) access devices.

[0084] The AMF network element has the functions of terminal device mobility management, registration management, connection management, legal monitoring, support for transmission of session management (SM) information between terminal devices and SMF, access authentication and access authorization.

[0085] The SMF network element has functions such as session management and roaming. The session management function includes, for example, session establishment, modification and release. The roaming function may include charging data collection and support for signaling transmission for authentication / authorization with external data networks.

[0086] The PSA network element is a functional network element of the user plane, which is mainly responsible for connecting to the external network and processing user messages, such as forwarding, billing, and legal interception. Optionally, the PSA network element can also receive data. Figure 1 Only two PSA network elements are shown, which are denoted as PSA network element 1 and PSA network element 2 respectively.

[0087] The BP device can receive uplink data packets from the terminal device and distribute them to the PSA network element corresponding to the source address according to the source address of the uplink data packet. The BP device can also receive downlink data packets from the PSA network element, and aggregate the downlink data packets received from the PSA network element and send them to the terminal device. Here, the BP device can also be implemented as a UPF network element.

[0088] A data network is a network that provides services to terminal devices. For example, some data networks provide Internet access to terminal devices, while other data networks provide text messaging functions to terminal devices.

[0089] Among them, the terminal device communicates with the AMF network element through the N1 interface, the AN device communicates with the AMF network element through the N2 interface, the AN device communicates with the BP device through the N3 interface, the BP device communicates with the SMF network element through the N4 interface, the BP device communicates with the UPF network element through the N9 interface, the UPF network element communicates with the SMF network element through the N4 interface, the UPF network element accesses the data network through the N6 interface, and the AMF network element communicates with the SMF network element through the N11 interface. Figure 1 In the figure, the dotted line shows a path that can perform control plane signaling interaction, and the solid line shows a path that can perform user plane data interaction.

[0090] It should be noted that the data networks connected to different PSA network elements are located in different data centers (DC). Figure 1 The following example illustrates the distribution of data networks. Figure 2, the data network connected to PSA network element 1 can be a central data network (central data network) or a central data center (central data center). In this case, PSA network element 1 can be recorded as central PSA, abbreviated as C-PSA. The data network connected to PSA network element 1 can also be a remote data network (remote data network) or a remote data center (remote data center). In this case, PSA network element 1 can be recorded as remote PSA, abbreviated as R-PSA. PSA network element 1 can also communicate with the DNS server in the above data network. The data network connected to PSA network element 2 is located in the local DC or edge data network (edge ​​data network, EDN). In this case, PSA network element 2 can be recorded as Local PSA, abbreviated as L-PSA. Different L-PSA network elements can be identified by different digital suffixes. For example, the first L-PSA network element can be recorded as L-PSA_1, and the second L-PSA network element can be recorded as L-PSA_2. PSA network element 2 can also communicate with the DNS server in the local DC. There may be no IP connectivity between PSA network elements and DNS servers located in different DCs, and they cannot communicate. For example, PSA network element 1 cannot communicate with the DNS server in the local DC. PSA network element 2 cannot communicate with the DNS server in the central DC. When PSA network element 2 exists at the location of the terminal device so that the terminal device can access the DN in the local DC, the SMF network element inserts the PSA network element 2 as a local PSA into the session path so that the terminal device can access the application in the local DN nearby. BP equipment and L-PSA network elements can be deployed separately or together. Figure 2 In the scenario shown, the function of the BP device and the function of the PSA network element 2 are implemented by the same network element, which may be the PSA network element 2.

[0091] Here, the local DC or edge data network can be implemented as a mobile edge computing (mobile / multi-access edge computing, MEC) node. Typically, an MEC node includes a MEC platform and a data plane functional network element. Among them, various application servers and DNS servers can be deployed on the MEC platform, and the embodiments of the present application do not specifically limit this. The MEC platform in the embodiments of the present application may also be referred to as a MEC system or others, and the embodiments of the present application do not specifically limit this. The data plane functional network element can be implemented by a PSA network element. An application server refers to a carrier that can provide corresponding services. For example, a WeChat application server can be a carrier that can provide WeChat services. Among them, the carrier can be a virtual device, such as a virtual machine or a container, or a physical device, and the embodiments of the present application do not specifically limit this.

[0092] The system 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 by the embodiments of the present application. It is known to those skilled in the art that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0093] The method for sending a domain name system request provided in an embodiment of the present application is described in detail below.

[0094] It should be noted that the message names between the network elements or the names of the parameters in the messages in the following embodiments of the present application are only examples, and other names may be used in the specific implementation. They are uniformly described here and will not be repeated below.

[0095] The embodiment of the present application provides a first method for sending a domain name system request, which is applied in the domain name resolution process. Figure 3 The method for sending a domain name system request in an embodiment of the present application includes the following steps:

[0096] S301. The terminal device creates a PDU session.

[0097] Exemplarily, the terminal device initiates a session creation request message to create a PDU session. The PDU session creation process is completed by the network device (such as SMF network element and UPF network element) and the terminal device. The detailed implementation process of the session creation process can be referred to the prior art and will not be repeated here.

[0098] The user plane path of the PDU session includes: a path from the RAN device to the BP device, and a path from the BP device to the PSA network element. Here, the number of PSA network elements is two or more. The PSA network element can be a PSA network element in a local DC, or a PSA network element in a central DC. Accordingly, the terminal device is assigned multiple addresses. In actual application, the address assigned to the terminal device can be a specific address, such as an address of the fourth version of the Internet communication protocol (internet protocol version 4, IPv4), or an address prefix (prefix), such as an address prefix of the sixth version of the Internet communication protocol (internet protocol version 6, IPv6). One address of the terminal device corresponds to one PSA network element, and different addresses of the terminal device correspond to different PSA network elements. Multiple addresses of the terminal device can be allocated by the SMF network element, or by the PSA network element. In the case where the PSA network element allocates an address to the terminal device, one PSA network element allocates one address to the terminal device, and different PSA network elements allocate different addresses to the terminal device. For example, see Table 1, which shows the correspondence between the address of the terminal device and the PSA network element.

[0099] Table 1

[0100] The address of the terminal device PSA Network Elements The address of the terminal device @0 C-PSA Address of terminal device@1 L-PSA_1 … The address of the terminal device@n L-PSA_n

[0101] Refer to Table 1, which shows the (n+1) addresses of the terminal device, which are respectively recorded as: address of the terminal device @0, address of the terminal device @1, ..., address of the terminal device @n. The number of PSA network elements is (n+1), which are respectively recorded as: C-PSA, L-PSA_1, ..., L-PSA_n. In Table 1, there is a corresponding relationship between the addresses of the terminal devices and the PSA network elements in the same row. As shown in Table 1, "address of the terminal device @0" corresponds to the "C-PSA" network element, "address of the terminal device @1" corresponds to the "L-PSA_1" network element, ..., "address of the terminal device @n" corresponds to the "L-PSA_n" network element.

[0102] In addition, the PSA network element can serve or access a specific data network / data center. DNS servers can be deployed in these "data networks / data centers" to perform DNS resolution through the DNS servers. The DNS server can also be deployed on the PSA network element, and the DNS server can also be deployed on the path between the PSA network element and the "data network / data center". The embodiment of the present application does not limit the deployment location of the DNS server, and ensures that the PSA network element can send the DNS request information to the corresponding DNS server after receiving the DNS request information. In this way, there is a corresponding relationship between the DNS server and the "data network / data center", and there is also a corresponding relationship between the PSA and the "data network / data center". In other words, for the PSA network element and the DNS server that have a corresponding relationship with the same "data network / data center", the two can communicate, and there is a corresponding relationship. For example, see Table 2, which takes the "address of the DNS server" as an example to show the corresponding relationship between the PSA network element and the DNS server. Here, the address of the DNS server can be identified by an IP address or a domain name, etc. Here, the addresses of at least two DNS servers are different. In other words, the addresses of the DNS servers are not exactly the same. The addresses of different DNS servers can be the same or different.

[0103] Table 2

[0104] DNS server address PSA Network Elements IP@0 C-PSA IP@1 L-PSA_1 … IP@n L-PSA_n

[0105] Refer to Table 2, which shows the addresses of (n+1) DNS servers, which are respectively recorded as: IP@0, IP@1, ..., IP@n. Among them, "IP@0, IP@1, ..., IP@n" may have the same address. The number of PSA network elements is (n+1), which are respectively recorded as: C-PSA, L-PSA_1, ..., L-PSA_n. In Table 2, there is a corresponding relationship between the DNS servers and PSA network elements in the same row, as shown in Table 2. For example, "IP@0" corresponds to the "C-PSA" network element, "IP@1" corresponds to the "L-PSA_1" network element, ..., and "IP@n" corresponds to the "L-PSA_n" network element.

[0106] It should be noted that Table 1 only shows the "correspondence between the address of the terminal device and the PSA network element" in the form of a "table". Table 2 only shows the "correspondence between the PSA network element and the DNS server" in the form of a "table". Table 1 and Table 2 can be combined in the same table to present the "correspondence between the address of the terminal device and the PSA network element" and the "correspondence between the PSA network element and the DNS server", which is not limited in the embodiments of the present application.

[0107] S302: The terminal device determines the address of the first DNS server corresponding to the first application.

[0108] The first application may refer to a software product installed on a terminal device for accessing services provided by an application server. These software products may also be referred to as application clients.

[0109] The "first DNS server corresponding to the first application" means that the data network corresponding to the first DNS server is deployed with an application server corresponding to the first application. The address of the first DNS server can be identified by an IP address or a domain name.

[0110] Exemplarily, the first application may be a WeChat client on the terminal device. Accordingly, the application server is a WeChat application server that provides services for the WeChat client on the terminal device. The first DNS server is a DNS server that can resolve DNS request information including the WeChat application. Figure 2 Taking the scenario shown as an example, if the application server in the central DC has the application "WeChat" deployed on it, but the application server in the local DC has not, then the first DNS server can be the DNS server in the central DC, which can be recorded as the "C-DNS" server. On the contrary, if the application server in the central DC has not, but the application server in the local DC has, then the first DNS server is the DNS server in the central DC, which can be recorded as the "L-DNS" server.

[0111] It should be noted that, since different data networks may be deployed with different applications, the application servers in the same data network are usually resolved by the DNS server corresponding to the data network. Therefore, there is a certain correspondence between different applications and different DNS servers. For example, see Table 3-1. Table 3-1 takes "application identifier" and "DNS server address" as examples to show the "correspondence between different applications and different DNS servers." Here, the application identifier can be a fully qualified domain name (FQDN). There is a one-to-one correspondence between the data network and the address of the DNS server, so the "correspondence between different applications and different DNS servers" can also indicate which applications are deployed in the data network corresponding to the DNS server.

[0112] Table 3-1

[0113] Application ID DNS server address FQDN_1 IP@1 FQDN_1 IP@2 FQDN_2 IP@1 FQDN_3 IP@3 … … FQDN_n IP@2

[0114] See Table 3-1, which shows the identifiers of n applications, which are respectively recorded as: FQDN_1, FQDN_2, ..., FQDN_n. The number of DNS servers is at least two. Table 3-1 shows the addresses of three DNS servers, which are respectively recorded as: IP@1, IP@2 and IP@3. In Table 3-1, there is a corresponding relationship between the applications and DNS servers in the same row. As shown in Table 3-1, there is a corresponding relationship between the application identified by "FQDN_1" and the DNS server with the address "IP@1", there is a corresponding relationship between the application identified by "FQDN_1" and the DNS server with the address "IP@2", there is a corresponding relationship between the application identified by "FQDN_2" and the DNS server with the address "IP@1", there is a corresponding relationship between the application identified by "FQDN_3" and the DNS server with the address "IP@3", there is a corresponding relationship between the application identified by "FQDN_n" and the DNS server with the address "IP@2". The terminal device may pre-configure the information of "the correspondence between the application and the DNS server", or the SMF network element, PCF network element or other network element may send the information of "the correspondence between the application and the DNS server" to the terminal device. For example, when the SMF network element or PCF network element inserts the BP device into the user plane path of the PDU session, the user routing selection policy (URSP) sent to the terminal device carries the above-mentioned "the correspondence between the application and the DNS server" information.

[0115] Here, there are many ways for the terminal device to determine the address of the first DNS server corresponding to the first application, such as but not limited to: Figure 4 The process shown:

[0116] S3021, the SMF network element sends the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application to the terminal device. Correspondingly, the terminal device receives the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application from the SMF network element.

[0117] For example, the "identification of the first application and the address of the DNS server corresponding to the identification of the first application" can be presented in a table or other form, which is not limited in the embodiments of the present application. Taking Table 3-1 as an example, the first application can be one of the n applications in Table 3-1.

[0118] S3022: The terminal device determines the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application.

[0119] Here, if the identifier of the first application corresponds to the address of a DNS server, the address of the DNS server is the address of the first DNS server. Exemplarily, still taking the "correspondence between different applications and different DNS servers" shown in Table 3-1 as an example, the identifier of the first application is "FQDN_3". In Table 3-1, the application identified by "FQDN_3" only has a corresponding relationship with the DNS server with the address "IP@3", that is, only the DNS server with the address "IP@3" can communicate with the application server where the "first application" is deployed. In this way, the address of the first DNS server is "IP@3".

[0120] If the identifier of the first application corresponds to the addresses of two or more DNS servers, the terminal device determines a DNS server from multiple DNS servers as the first DNS server based on a certain preset strategy. Exemplarily, the terminal device determines the first DNS server that satisfies the preset strategy from multiple DNS servers. The preset strategy includes at least one of the following:

[0121] Item 1: The priority of the first DNS server satisfies the priority condition among the priorities of the multiple DNS servers. For example, the priority of the first DNS server is the highest among the priorities of the multiple DNS servers.

[0122] Item 2: The distance between the first DNS server and the terminal device satisfies the interval distance condition. For example, the distance between the first DNS server and the terminal device is less than or equal to the distance threshold, or, among the distances between the above-mentioned multiple DNS servers and the terminal device, the distance between the first DNS server and the terminal device is the smallest.

[0123] Exemplarily, still taking the "correspondence between different applications and different DNS servers" shown in Table 3-1 as an example, the identifier of the first application is "FQDN_1". In Table 3-1, there is a correspondence between the application identified by "FQDN_1" and the DNS server with the address "IP@1" and the DNS server with the address "IP@2", that is, the DNS server with the address "IP@1" and the DNS server with the address "IP@2" can resolve the DNS request information corresponding to the "first application". In the case where the preset policy is implemented as the second item, if the distance between the DNS server with the address "IP@1" and the terminal device meets the interval distance condition, the address of the first DNS server is "IP@1". If the distance between the DNS server with the address "IP@2" and the terminal device meets the interval distance condition, the address of the first DNS server is "IP@2".

[0124] For example, see Table 3-2, in which, in addition to showing the "correspondence between different applications and different DNS servers", the "priorities of different DNS servers" are also shown.

[0125] Table 3-2

[0126] Application ID DNS server address Priority FQDN_1 IP@1 3 FQDN_1 IP@2 2 FQDN_2 IP@1 3 FQDN_3 IP@3 4 … … … FQDN_n IP@2 2

[0127] Refer to Table 3-2. In Table 3-2, the relevant description of "the correspondence between different applications and different DNS servers" can be found in the introduction of Table 3-1, which will not be repeated here. In Table 3-2, the priority of the DNS server with the address "IP@1" is 3, the priority of the DNS server with the address "IP@2" is 2, and the priority of the DNS server with the address "IP@3" is 4. Here, in the "Priority" column, the larger the value of the number, the higher the corresponding priority. Or vice versa, the larger the value of the number, the lower the corresponding priority, which is not limited in the embodiments of the present application.

[0128] Taking the "correspondence between different applications and different DNS servers" shown in Table 3-2 as an example, the first application is identified as "FQDN_1". In Table 3-2, there is a correspondence between the application identified by "FQDN_1" and the DNS server with the address "IP@1" and the DNS server with the address "IP@2". In the case where the preset policy is implemented as the first item, if the priority of the DNS server with the address "IP@1" is higher than the DNS server with the address "IP@2", the address of the first DNS server is "IP@1".

[0129] It should be noted that, in the embodiment of the present application, only "priority" and "distance" are used as examples to exemplify the specific implementation of the preset strategy. In the actual application process, other preset strategies can also be set according to the actual application requirements, and the embodiment of the present application does not limit this.

[0130] In this way, when the SMF network element provides the terminal device with "the identification of the first application and the address of the DNS server corresponding to the identification of the first application", the terminal device can determine the address of the first DNS server corresponding to the first application based on the information provided by the SMF network element.

[0131] S303: The terminal device determines a first address of the terminal device according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server.

[0132] The description of "the address of the terminal device" is as follows: The terminal device may have one or more addresses. The address of the terminal device may be allocated by an SMF network element or a UPF (PSA) network element. One address of the terminal device corresponds to one PSA network element, and different addresses of the terminal device correspond to different PSA network elements. The PSA network element corresponding to the first address of the terminal device is recorded as the first PSA network element.

[0133] Among them, the description of "the address of the terminal device corresponding to the address of the first DNS server" is as follows: Since there is a corresponding relationship between the PSA network element and the DNS server, see the relevant description in Table 2 for details. In addition, there is also a corresponding relationship between the PSA network element and the address of the terminal device, see the relevant description in Table 1 for details. For the address of the terminal device and the DNS server that have a corresponding relationship with the same "PSA network element", there is also a corresponding relationship between the two. For example, see Table 4, which takes the "address of the DNS server" as an example to show the "correspondence between the address of the DNS server and the address of the terminal device".

[0134] Table 4

[0135]

[0136]

[0137] Refer to Table 4, which shows the (n+1) addresses of the terminal device, which are respectively recorded as: address of the terminal device @0, address of the terminal device @1, ..., address of the terminal device @n. The number of DNS servers is (n+1), and the addresses of the (n+1) DNS servers are respectively recorded as: IP@0, IP@1, IP@2, ..., IP@n. In Table 4, there is a corresponding relationship between the addresses of the terminal devices and the DNS servers located in the same row. As shown in Table 4, there is a corresponding relationship between "address of the terminal device @0" and the DNS server identified by the address "IP@0", there is a corresponding relationship between "address of the terminal device @1" and the DNS server identified by the address "IP@1", there is a corresponding relationship between "address of the terminal device @2" and the DNS server identified by the address "IP@2", ..., there is a corresponding relationship between "address of the terminal device @n" and the DNS server identified by the address "IP@n".

[0138] For example, still taking the "correspondence between the DNS server and the address of the terminal device" shown in Table 4 as an example, if the address of the first DNS server is "IP@1", the first address of the terminal device is "the address of the terminal device@1". If the address of the first DNS server is "IP@2", the first address of the terminal device is "the address of the terminal device@2".

[0139] The information of “the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server” may be information pre-configured by the terminal device, or may be information issued by an SMF network element, a PCF network element or other network element to the terminal device, for example:

[0140] The SMF network element sends the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server to the terminal device. Correspondingly, the terminal device receives the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server from the SMF network element.

[0141] Exemplarily, when the SMF network element inserts the BP device into the user plane path of the PDU session, the SMF network element sends the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server to the terminal device. For example, the above information is carried in the path selection rule (routing rule) sent to the terminal device.

[0142] S304: The terminal device sends DNS request information to the BP device. Correspondingly, the BP device receives the DNS request information from the terminal device.

[0143] The DNS request information includes the identifier of the first application, the address of the first DNS server and the first address of the terminal device. Here, the source address of the DNS request information is the first address of the terminal device, and the destination address of the DNS request information is the address of the first DNS server.

[0144] Exemplarily, the identifier of the first application is "FQDN_1", the address of the first DNS server is "IP@1", and the address of the terminal device is "the address of the terminal device@1". In this case, the identifier of the application in the DNS request information is "FQDN_1", the source address of the DNS request information is "the address of the terminal device@1", and the destination address of the DNS request information is "IP@1".

[0145] For example, see Figure 5, the terminal device sends a DNS request message to the BP device. Correspondingly, the BP device receives the DNS request message from the terminal device. Afterwards, the BP device determines the PSA network element corresponding to the source address according to the source address of the DNS request message, and then sends the DNS request message to the PSA network element corresponding to the source address. Correspondingly, the PSA network element corresponding to the source address receives the DNS request message from the BP device. Here, if the PSA network element corresponding to the source address is a "C-PSA" network element, the BP device sends a DNS request message to the C-PSA network element. Correspondingly, the C-PSA network element receives the DNS request message from the BP device. Afterwards, the C-PSA network element sends a DNS request message to the C-DNS server according to the destination address in the DNS request message. Correspondingly, the C-DNS server receives the DNS request message from the C-PSA network element, parses the DNS request message, and obtains the response message for the DNS request message. Among them, the response message includes the IP address of the application server. The response information is then transmitted to the terminal device by the C-DNS server, C-PSA network element, and BP device, providing the terminal device with the IP address of the application server, so that data can be transmitted between the terminal device and the application server. If the PSA network element corresponding to the source address is an "L-PSA" network element, the BP device sends a DNS request message to the L-PSA network element. Correspondingly, the L-PSA network element receives the DNS request information from the BP device. Afterwards, the L-PSA network element sends a DNS request message to the L-DNS server according to the destination address in the DNS request information. Correspondingly, the L-DNS server receives the DNS request information from the L-PSA network element, and parses the DNS request information to obtain the response information of the DNS request information. The response information is then transmitted from the L-DNS server, L-PSA network element, and BP device to the terminal device, providing the terminal device with the IP address of the application server.

[0146] It should be noted that when the location of the terminal device changes, the network equipment (such as SMF network element or PCF network element, etc.) provides the terminal device with "the correspondence between different applications and different DNS servers" and "the correspondence between the DNS server and the address of the terminal device".

[0147] In the method for sending a domain name system request in the embodiment of the present application, after the terminal device determines the address of the first DNS server corresponding to the first application, it can also determine the first address of the terminal device according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server. Since there is a corresponding relationship between the address of the first DNS server and the first address of the terminal device, and the first address of the terminal device corresponds to a PSA network element, that is, the first DNS server can communicate with the PSA network element corresponding to the first address of the terminal device. Since the DNS request information sent by the terminal device includes the address of the above-mentioned first DNS server and the first address of the terminal device, in this way, the DNS request information can be transmitted to the first DNS server through the PSA network element corresponding to the terminal device, thereby improving the success rate of DNS resolution and reducing the phenomenon of "DNS resolution failure" caused by "the inability to communicate between the DNS server and the PSA network element" in the prior art.

[0148] The embodiment of the present application provides a second method for sending a domain name system request, which is applied in the domain name resolution process. Figure 6 The method for sending a domain name system request in an embodiment of the present application includes the following steps:

[0149] S601: The terminal device creates a PDU session.

[0150] The specific implementation process of S601 can refer to the relevant description of S301, which will not be repeated here.

[0151] S602: The terminal device sends a DNS request message to the BP device. Correspondingly, the BP device receives the DNS request message from the terminal device.

[0152] The DNS request information includes the identifier of the first application, the source address and the destination address. In S602, the source address and the destination address selected by the terminal device are not limited. The specific implementation process can refer to the prior art and will not be repeated here.

[0153] S603: The BP device updates at least one of the source address and the destination address in the DNS request information to obtain updated DNS request information.

[0154] The source address in the updated DNS request information is the first address of the terminal device, and the destination address in the updated DNS request information is the address of the first DNS server. Here, in the updated DNS request information, there is a corresponding relationship between the PSA network element corresponding to the source address and the first DNS server, and they can communicate. Please refer to the relevant description of S303, which will not be repeated here, to avoid the phenomenon of "DNS resolution failure" caused by the inability to communicate between the PSA network element and the DNS server.

[0155] There are many ways for "the BP device to update at least one of the source address and the destination address in the DNS request information to obtain the updated DNS request information". The following are three examples for explanation:

[0156] Example 1: The BP device updates at least one of a source address and a destination address in the DNS request information according to an identifier of the first application in the DNS request information to obtain updated DNS request information.

[0157] Here, the source address and the destination address in the update DNS request information are determined according to the identifier of the first application. The application server corresponding to the first application is deployed in the data network corresponding to the first DNS server, so the first DNS server can resolve the DNS request information. After determining the first DNS server, the PSA network element corresponding to the first DNS server can be determined, and then the first address of the terminal device can be determined. The PSA network element corresponding to the first address of the terminal device can communicate with the first DNS server to improve the efficiency of DNS request information resolution.

[0158] For example, see Figure 7 In order to obtain the updated DNS request information, the BP device performs the following steps:

[0159] S6031. The BP device determines the address of the first DNS server corresponding to the identifier of the first application.

[0160] Exemplarily, the BP device can determine the address of the first DNS server corresponding to the first application according to the "correspondence between different applications and different DNS servers". Here, the introduction of "correspondence between different applications and different DNS servers" can be referred to the relevant description of S302, which will not be repeated here. S6031 can be specifically implemented as the following steps 1 and 2:

[0161] Step 1: The SMF network element sends the first application identifier and the address of the DNS server corresponding to the first application identifier to the BP device. Correspondingly, the BP device receives the first application identifier and the address of the DNS server corresponding to the first application identifier from the SMF network element.

[0162] For example, the "identification of the first application and the address of the DNS server corresponding to the identification of the first application" can be presented in the form of a table or other forms, which is not limited in the embodiments of the present application. Taking Table 3-1 as an example, the first application can be one of the n applications in Table 3-1.

[0163] Alternatively, step one may also be implemented as follows: the SMF network element sends the identifier of the application deployed in the data network to the BP device. Accordingly, the BP device receives the identifier of the application deployed in the data network from the SMF network element. Alternatively, step one may also be implemented as follows: the SMF network element sends the identifier of the application server deployed in the data network to the BP device. Accordingly, the BP device receives the identifier of the application server deployed in the data network from the SMF network element. As mentioned above, there is a corresponding relationship between the data network and the DNS server, so the BP device can determine the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application based on the information received from the SMF network element.

[0164] Step 2: The BP device determines the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application.

[0165] Here, for the introduction of step 2, please refer to the relevant description of S3022. That is, the terminal device in S3022 is replaced by the BP device, and the specific method flow is the same, which will not be repeated here.

[0166] After the BP device determines the address of the first DNS server, if the destination address in the DNS request information is consistent with the address of the first DNS server, the BP device does not need to execute S6032. If the destination address in the DNS request information is inconsistent with the address of the first DNS server, the BP device executes S6032:

[0167] S6032. The BP device updates the destination address in the DNS request information to the address of the first DNS server.

[0168] Exemplarily, if the address of the first DNS server is "IP@2" and the destination address in the DNS request information is "IP@3", the BP device replaces the destination address in the DNS request information with "IP@2".

[0169] S6033: The BP device determines the first address of the terminal device according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server.

[0170] Here, for the introduction of S6033, please refer to the relevant description of S303. That is to say, the terminal device in S303 is replaced by the BP device, and the specific method and process are the same, which will not be repeated here.

[0171] After the BP device determines the first address of the terminal device, if the source address in the DNS request information is consistent with the first address of the terminal device, the BP device does not need to execute S6034. If the source address in the DNS request information is inconsistent with the first address of the terminal device, the BP device executes S6034:

[0172] S6034. The BP device sets the source address in the DNS request information as the first address of the terminal device.

[0173] Exemplarily, if the first address of the terminal device is "the address of the terminal device@2" and the source address in the DNS request information is "the address of the terminal device@3", the BP device replaces the source address in the DNS request information with "the address of the terminal device@2".

[0174] In this way, the BP device updates the source address and the destination address in the DNS request information based on the identifier of the application in the DNS request information to obtain the updated DNS request information.

[0175] Example 2: The BP device updates the destination address in the DNS request information according to the source address in the DNS request information.

[0176] Exemplarily, still taking the "correspondence between the DNS server and the address of the terminal device" shown in Table 4 as an example, when the source address in the DNS request information is "the address of the terminal device @1", and the destination address in the DNS request information is not "IP@1", the BP device updates the destination address in the DNS request information to "IP@1". When the source address in the DNS request information is "the address of the terminal device @2", and the destination address in the DNS request information is not "IP@2", the BP device updates the destination address in the DNS request information to "IP@2".

[0177] Here, the BP device updates the destination address in the DNS request information based on the source address in the DNS request information to obtain the updated DNS request information.

[0178] In Example 2, as a possible implementation, the BP device performs the following steps 3 and 4:

[0179] Step 3: If the source address in the DNS request information is the first address of the terminal device, the BP device determines the address of the first DNS server according to the first address of the terminal device and the address of the DNS server corresponding to the first address of the terminal device.

[0180] Exemplarily, still taking the "correspondence between the DNS server and the address of the terminal device" shown in Table 4 as an example, when the source address in the DNS request information is "the address of the terminal device @1", in combination with Table 4, the BP device determines that the address of the first DNS server is "IP@1". When the source address in the DNS request information is "the address of the terminal device @2", the BP device determines that the address of the first DNS server is "IP@2".

[0181] Here, the information of "the first address of the terminal device and the address of the DNS server corresponding to the first address of the terminal device" can be the pre-configured information of the BP device, or it can be the information sent by the SMF network element to the BP device, that is, the SMF network element sends the first address of the terminal device and the address of the DNS server corresponding to the first address of the terminal device to the BP device. Correspondingly, the BP device receives the first address of the terminal device and the address of the DNS server corresponding to the first address of the terminal device from the SMF network element.

[0182] Step 4: The BP device updates the destination address in the DNS request information to the address of the first DNS server.

[0183] Exemplarily, when the source address in the DNS request information is "the address of the terminal device @1", and the destination address in the DNS request information is not "IP@1", the BP device updates the destination address in the DNS request information to "IP@1". When the source address in the DNS request information is "the address of the terminal device @2", and the destination address in the DNS request information is not "IP@2", the BP device updates the destination address in the DNS request information to "IP@2".

[0184] In this way, when the BP device determines that the source address in the DNS request information is the first address of the terminal device, it updates the destination address in the DNS request information based on the source address in the DNS request information to obtain updated DNS request information.

[0185] Example 3: The BP device updates the source address in the DNS request information according to the destination address in the DNS request information.

[0186] Exemplarily, still taking the "correspondence between the DNS server and the address of the terminal device" shown in Table 4 as an example, when the destination address in the DNS request information is "IP@1" and the source address in the DNS request information is not "the address of the terminal device@1", the BP device updates the source address in the DNS request information to "the address of the terminal device@1". When the destination address in the DNS request information is "IP@2" and the source address in the DNS request information is not "the address of the terminal device@2", the BP device updates the source address in the DNS request information to "the address of the terminal device@2".

[0187] Here, the BP device updates the source address in the DNS request information based on the destination address in the DNS request information to obtain updated DNS request information.

[0188] In Example 3, as a possible implementation, the BP device performs the following steps 5 and 6:

[0189] Step 5: If the destination address in the DNS request information is the address of the first DNS server, the BP device determines the first address of the terminal device according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server.

[0190] For example, still taking the "correspondence between the DNS server and the address of the terminal device" shown in Table 4 as an example, when the destination address in the DNS request information is "IP@1", in combination with Table 4, the BP device determines that the first address of the terminal device is "the address of the terminal device@1". When the destination address in the DNS request information is "IP@2", in combination with Table 4, the BP device determines that the first address of the terminal device is "the address of the terminal device@2".

[0191] Here, the information of "the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server" can be the pre-configured information of the BP device, or it can be the information sent by the SMF network element to the BP device, that is, the SMF network element sends the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server to the BP device. Correspondingly, the BP device receives the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server from the terminal device of the SMF network element.

[0192] Step 6: The BP device updates the source address in the DNS request information to the first address of the terminal device.

[0193] Exemplarily, when the destination address in the DNS request information is "IP@1" and the source address in the DNS request information is not "the address of the terminal device@1", the BP device updates the source address in the DNS request information to "the address of the terminal device@1". When the destination address in the DNS request information is "IP@2" and the source address in the DNS request information is not "the address of the terminal device@2", the BP device updates the source address in the DNS request information to "the address of the terminal device@2".

[0194] In this way, when the BP device determines that the destination address in the DNS request information is the address of the first DNS server, it updates the source address in the DNS request information based on the destination address in the DNS request information to obtain updated DNS request information.

[0195] It should be noted that in the above example 1, the update rule of the BP device is "update at least one of the source address and the destination address in the DNS request information based on the identifier of the first application in the DNS request information". In the above example 2, the update rule of the BP device is "update the destination address in the DNS request information based on the source address in the DNS request information". In the above example 3, the update rule of the BP device is "update the source address in the DNS request information based on the destination address in the DNS request information". The update rule of any of the above three examples can be pre-configured on the BP device, or it can be configured for the BP device by the SMF network element. The update rule of any of the above three examples can be configured at the granularity of the terminal device, that is, the update rules for different DNS request information sent by the same terminal device are the same, and the update rules for DNS request information of different terminal devices can be the same or different. In this case, if N terminal devices are served by the BP device, the BP device needs to configure N update rules. The update rule of any of the above three examples can also be configured at the granularity of "BP device", that is, for a BP device, the BP device uses the same update rule to update the source address and / or destination address in the DNS request information. In this case, if N terminal devices are all served by the BP device, the BP device needs to configure one update rule.

[0196] S604: The BP device sends the updated DNS request information to the first PSA network element according to the source address in the updated DNS request information. Correspondingly, the first PSA network element receives the updated DNS request information from the BP device.

[0197] The first PSA network element is a PSA network element corresponding to the first address of the terminal device.

[0198] Exemplarily, the BP device determines the first PSA network element according to the source address in the updated DNS request information, and then the BP device sends the updated DNS request information to the first PSA network element. The specific implementation process can be referred to the prior art and will not be repeated here.

[0199] S605: The first PSA network element sends updated DNS request information to the first DNS server according to the destination address in the updated DNS request information. Correspondingly, the first DNS server receives the updated DNS request information from the first PSA network element.

[0200] Among them, there is a corresponding relationship between the first DNS server and the first PSA network element.

[0201] S606: The first DNS server parses the updated DNS request information and obtains response information.

[0202] The DNS request information includes the identifier of the first application. Correspondingly, the response information includes the IP address of the application server corresponding to the first application. The source address of the response information is the destination address of the updated DNS request information, and the destination address of the response information is the source address of the updated DNS request information. The specific implementation process of S606 can be referred to the prior art and will not be repeated here.

[0203] S607: The first DNS server sends response information to the first PSA network element. Correspondingly, the first PSA network element receives the response information from the first DNS server.

[0204] Exemplarily, the destination address of the response information is the source address of the updated DNS request information, that is, the first address of the terminal device. The first DNS server sends the response information to the first PSA network element according to the destination address of the response information. The specific implementation process can be referred to the prior art and will not be repeated here.

[0205] S608: The first PSA network element sends response information to the BP device. Correspondingly, the BP device receives the response information from the first PSA network element.

[0206] Here, the source address of the response information is the destination address of the updated DNS request information, and the destination address of the response information is the source address of the updated DNS request information.

[0207] S609: The BP device updates at least one of the source address and the destination address in the response information, and obtains updated response information.

[0208] The source address in the updated response information is the destination address of the DNS request information before the update, and the destination address in the updated response information is the source address of the DNS request information before the update.

[0209] For example, if in S603, the BP device replaces the source address in the DNS request information from "the address of the terminal device @3" to "the address of the terminal device @2", then in S609, the BP device replaces the destination address in the response information from "the address of the terminal device @2" to "the address of the terminal device @3". If in S603, the BP device replaces the destination address in the DNS request information from "IP@1" to "IP@2", then in S609, the BP device replaces the source address in the response information from "IP@2" to "IP@1".

[0210] S610: The BP device sends updated response information to the terminal device. Correspondingly, the terminal device receives the updated response information from the BP device.

[0211] Here, the updated response information includes the IP address of the application server corresponding to the first application, the destination address of the DNS request information before the update, and the source address of the DNS request information before the update. After the terminal device executes S602 to send the DNS request information, it monitors the response message carrying the source address and the destination address of the DNS request information before the update. The BP device can replace at least one of the source address and the destination address in the response information to ensure that the terminal device can monitor the response message carrying the source address and the destination address of the DNS request information before the update.

[0212] In the method for sending a domain name system request in the embodiment of the present application, after the BP device receives the DNS request information from the terminal device, it can update at least one of the source address and the destination address in the DNS request information, obtain the updated DNS request information, and then send the updated DNS request information. Since the source address in the updated DNS request information is the first address of the terminal device, the destination address in the updated DNS request information is the address of the first DNS server. The first PSA network element corresponding to the first address of the terminal device can communicate with the first DNS server, so that the updated DNS request information can be transmitted to the first DNS server through the first PSA network element, thereby improving the success rate of DNS resolution and reducing the phenomenon of "DNS resolution failure" caused by "the inability to communicate between the DNS server and the PSA network element" in the prior art.

[0213] The embodiment of the present application provides a third method for sending a domain name system request, which is applied in the domain name resolution process. Figure 8 The method for sending a domain name system request in an embodiment of the present application includes the following steps:

[0214] S801. The terminal device creates a PDU session.

[0215] The specific implementation process of S801 can refer to the relevant description of S301, which will not be repeated here. As shown in Table 1, the terminal device is assigned multiple addresses. Among them, one address in the multiple addresses corresponds to a PSA network element, and different addresses in the multiple addresses correspond to different PSA network elements.

[0216] It should be noted that, in the process of inserting the BP device and the L-PSA network element in the user plane path of the PDU session, the SMF network element sends forwarding rule information to the C-PSA network element and the L-PSA network element respectively to instruct the C-PSA network element and the L-PSA network element to send the data packet to the BP device when receiving a data packet with a specific destination address. Specifically, the forwarding rule information sent to the C-PSA network element is used to instruct the C-PSA network element to send the data packet to the BP device when receiving a data packet with a destination address of "the address of the terminal device @1", "the address of the terminal device @2", ..., "the address of the terminal device @n". If the terminal device is assigned N addresses, the corresponding number of destination addresses in the forwarding rule information sent to the C-PSA network element is (N-1). Of course, multiple destination addresses can be combined in one forwarding rule information, or they can be carried in different forwarding rule information and transmitted to the C-PSA network element. This embodiment of the present application is not limited to this. Similarly, when forwarding rule information is sent to one of the L-PSA network elements, the L-PSA_1 network element is taken as an example to explain: the forwarding rule information sent to the L-PSA_1 network element is used to instruct the L-PSA_1 network element to send the data packet to the BP device when receiving a data packet with a destination address of "the address of the terminal device @1", "the address of the terminal device @2", ..., "the address of the terminal device @n". If the terminal device is assigned N addresses, the number of destination addresses in the forwarding rule information sent to the L-PSA_1 network element is (N-1) accordingly. Of course, multiple destination addresses can be combined in one forwarding rule information, or carried in different forwarding rule information and transmitted to the L-PSA_1 network element, which is not limited in this embodiment of the present application. For sending forwarding rule information to other network elements in the L-PSA network element, please refer to the above description, which will not be repeated here.

[0217] S802: The terminal device sends a DNS request message to the BP device. Correspondingly, the BP device receives the DNS request message from the terminal device.

[0218] The DNS request information includes an identifier of the first application, a source address, and a destination address. The source address of the DNS request information is the second address of the terminal device, corresponding to the second PSA network element. The destination address of the DNS request information is the address of the first DNS server, corresponding to the first PSA network element.

[0219] Exemplarily, taking the "correspondence between the address of the terminal device and the PSA network element" shown in Table 1 and the "correspondence between the PSA network element and the DNS server" shown in Table 2 as examples, if the source address of the DNS request information is "the address of the terminal device@0", the destination address of the DNS request information is "IP@1". In this case, the first DNS server is the "L-DNS_1" server, and the second PSA network element is the "C-PSA" network element. If the source address of the DNS request information is "the address of the terminal device@1", the destination address of the DNS request information is "IP@0". In this case, the first DNS server is the "C-DNS" server, and the second PSA network element is the "L-PSA_1" network element.

[0220] S803: The BP device sends a DNS request message to the first PSA network element corresponding to the destination address according to the destination address in the DNS request message. Correspondingly, the first PSA network element receives the DNS request message from the BP device.

[0221] Exemplarily, taking the "correspondence between PSA network elements and DNS servers" shown in Table 2 as an example, if the destination address of the DNS request information is "IP@0", the first PSA network element is the "C-PSA" network element. The BP device sends the DNS request information to the "C-PSA" network element. If the destination address of the DNS request information is "IP@1", the first PSA network element is the "L-PSA_1" network element. The BP device sends the DNS request information to the "L-PSA_1" network element.

[0222] S804: The first PSA network element sends a DNS request message to the first DNS server. Correspondingly, the first DNS server receives the DNS request message from the first PSA network element.

[0223] Exemplarily, the first PSA network element sends DNS request information to the first DNS server according to the destination address in the DNS request information. If the first PSA network element is a "C-PSA" network element, the first DNS server is a "C-DNS" server. The "C-PSA" network element sends DNS request information to the "C-DNS" server. If the first PSA network element is an "L-PSA_1" network element, the first server is an "L-DNS" server. The "L-PSA" network element sends DNS request information to the "L-DNS" server. The specific implementation process of S804 can be referred to the prior art and will not be repeated here.

[0224] S805: The first DNS server resolves the DNS request information and obtains response information.

[0225] The DNS request information includes the identifier of the first application. Correspondingly, the response information includes the IP address of the application server corresponding to the first application. The source address of the response information is the destination address of the DNS request information, and the destination address of the response information is the source address of the DNS request information. The specific implementation process of S805 can be referred to the prior art and will not be repeated here.

[0226] S806: The first DNS server sends response information to the first PSA network element. Correspondingly, the first PSA network element receives the response information from the first DNS server.

[0227] The source address of the response information is the address of the first DNS server, and the destination address of the response information is the second address of the terminal device. The second address of the terminal device corresponds to the second PSA network element. Here, S806 can be specifically implemented as the following process:

[0228] The first PSA network element receives response information for the DNS request information from the first DNS server through a tunnel between the first PSA network element and the first DNS server.

[0229] Wherein, a tunnel is established between the first PSA network element and the first DNS server. When the destination address of the response information is the second address of the terminal device and the source address of the response information is the address of the first DNS server, since the second address of the terminal device corresponds to the second PSA network element, the response information can be transmitted through the tunnel between the first PSA network element and the first DNS server.

[0230] Exemplarily, the destination address of the response information is "the address of the terminal device @0", and the source address of the response information is "IP@1". In this case, the first DNS server is the "L-DNS_1" server, and the first PSA network element is the "L-PSA_1" network element. Since the response information can be transmitted from the first DNS server to the first PSA network element through a tunnel. Therefore, in addition to carrying the source address and the destination address, the response information also needs to encapsulate the address of the tunnel between the first PSA network element and the first DNS server to shield the destination address in the response information, so that the response information can be transmitted from the first DNS server to the first PSA network element.

[0231] S807: The first PSA network element sends response information to the BP device according to the forwarding rule information. Correspondingly, the BP device receives the response information from the first PSA network element.

[0232] For the related description of the forwarding rule information, please refer to the introduction of S801, which will not be repeated here. The first PSA network element sends response information to the BP device based on the forwarding rule information. Here, the forwarding rule information indicates that the first PSA network element sends a data packet with a destination address of the second address to the BP device. The data packet includes the above response information.

[0233] The forwarding rule information may be pre-configured information or information configured by the SMF network element for the first PSA. That is, the SMF network element sends the forwarding rule information to the first PSA network element. Correspondingly, the first PSA network element receives the forwarding rule information from the SMF network element.

[0234] S808: The BP device sends response information to the terminal device. Correspondingly, the terminal device receives the response information from the BP device.

[0235] Here, the response information includes the IP address of the application server corresponding to the first application, the destination address of the DNS request information, and the source address of the DNS request information.

[0236] In the method for sending a domain name system request in the embodiment of the present application, after the BP device receives the DNS request information from the terminal device, it sends the DNS request information to the first PSA network element corresponding to the destination address according to the destination address in the DNS request information. Since the destination address of the DNS request information corresponds to the first PSA network element, the destination address of the DNS request information is the address of the first DNS server, and the first DNS server and the first PSA network element can communicate with each other, it is possible to reduce the phenomenon of "DNS resolution failure" caused by "the DNS server and the PSA network element cannot communicate" in the prior art, and improve the success rate of DNS resolution. In the process of the first DNS server feeding back the response information, after the first PSA network element receives the response information from the first DNS server, even if the destination address of the response information is the second address of the terminal device, corresponding to the second PSA network element, the first PSA network element can also send the response information to the BP device according to the forwarding rule information, so that the response information can be provided to the terminal device through the BP device.

[0237] The above mainly introduces the scheme provided by the embodiment of the present application from the perspective of interaction between various network elements. Accordingly, the embodiment of the present application also provides a sending device for a domain name system request, which can be a network element in the above method embodiment, or a device including the above network element, or a component that can be used for a network element. It can be understood that in order to realize the above functions, the sending device of the domain name system request includes a hardware structure and / or software module corresponding to each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed in this article, 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 exceed the scope of the present application.

[0238] Fig. 9 The schematic diagram of the structure of a device 900 for sending a domain name system request is shown. The device 900 for sending a domain name system request comprises a transceiver module 901 and a processing module 902 .

[0239] For example, the sending device 900 of the domain name system request is used as the method in the above embodiment. Figure 3 For example, the terminal device

[0240] The processing module 902 is used to determine the address of the first domain name system DNS server corresponding to the first application. The processing module 902 is also used to determine the first address of the terminal device according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server. The transceiver module 901 is used to send DNS request information. The DNS request information includes the identifier of the first application, the address of the first DNS server and the first address of the terminal device.

[0241] In a possible design, the transceiver module 901 is also used to receive the address of the first DNS server from the session management function SMF network element and the address of the terminal device corresponding to the address of the first DNS server.

[0242] In one possible design, the transceiver module 901 is used to receive the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application from the SMF network element. The processing module 902 is used to determine the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application.

[0243] In a possible design, the identifier of the first application corresponds to multiple DNS servers. The processing module 902 is specifically used to: determine a first DNS server that meets a preset policy from the multiple DNS servers. The preset policy includes at least one of the following: the priority of the first DNS server meets the priority condition among the priorities of the multiple DNS servers; the distance between the first DNS server and the terminal device meets the interval distance condition.

[0244] For example, the sending device 900 of the domain name system request is used as the method in the above embodiment. Figure 6 Take the BP device as an example,

[0245] The transceiver module 901 is used to receive domain name system DNS request information from a terminal device. The processing module 902 is used to update at least one of the source address and the destination address in the DNS request information to obtain updated DNS request information. The source address in the updated DNS request information is the first address of the terminal device, and the destination address in the updated DNS request information is the address of the first DNS server. The transceiver module 901 is also used to send the updated DNS request information to the first packet data unit session anchor PSA network element according to the source address in the updated DNS request information. The first PSA network element corresponds to the first address of the terminal device, and the destination address in the updated DNS request information enables the updated DNS request information to be sent by the first PSA network element to the first DNS server.

[0246] In one possible design, the processing module 902 is specifically used to: update at least one of the source address and the destination address in the DNS request information according to the identifier of the first application in the DNS request information, or, update the destination address in the DNS request information according to the source address in the DNS request information, or, update the source address in the DNS request information according to the destination address in the DNS request information.

[0247] In one possible design, the processing module 902 is specifically used to: determine the address of the first DNS server corresponding to the identifier of the first application; update the destination address in the DNS request information to the address of the first DNS server; determine the first address of the terminal device based on the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server; and set the source address in the DNS request information to the first address of the terminal device.

[0248] In one possible design, the transceiver module 901 is used to receive the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application from the session management function SMF network element. The processing module 902 is used to determine the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application.

[0249] In one possible design, the processing module 902 is specifically used to: if the destination address in the DNS request information is the address of the first DNS server, then determine the first address of the terminal device based on the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server, and update the source address in the DNS request information to the first address of the terminal device.

[0250] In one possible design, the transceiver module 901 is also used to receive the address of the first DNS server from the SMF network element and the address of the terminal device corresponding to the address of the first DNS server.

[0251] In one possible design, the processing module 902 is specifically used to: if the source address in the DNS request information is the first address of the terminal device, then determine the address of the first DNS server according to the first address of the terminal device and the address of the DNS server corresponding to the first address of the terminal device, and update the destination address in the DNS request information to the address of the first DNS server.

[0252] In one possible design, the transceiver module 901 is also used to receive a first address of a terminal device from the SMF network element and an address of a DNS server corresponding to the first address of the terminal device.

[0253] In one possible design, the transceiver module 901 is further used to receive response information to the DNS request information from the first PSA network element. The processing module 902 is used to update at least one of the source address and the destination address in the response information to obtain updated response information. The source address in the updated response information is the destination address of the DNS request information before the update, and the destination address in the updated response information is the source address of the DNS request information before the update. The transceiver module 901 is also used to send the updated response information to the terminal device.

[0254] For example, the sending device 900 of the domain name system request is used as the method in the above embodiment. Figure 8 Take the BP device as an example.

[0255] The transceiver module 901 is used to receive a domain name system DNS request information from a terminal device. The transceiver module 901 is also used to send the DNS request information to a first packet data unit session anchor PSA network element corresponding to the destination address according to the destination address in the DNS request information, so as to enable the DNS request information to be sent from the first PSA network element to the first DNS server.

[0256] For example, the sending device 900 of the domain name system request is used as the method in the above embodiment. Figure 8 Take the first PSA network element as an example:

[0257] The transceiver module 901 is used to send a DNS request message to the first domain name system DNS server. The DNS request message includes the address of the first DNS server and the second address of the terminal device corresponding to the second PSA network element. The transceiver module 901 is also used to receive response information for the DNS request message from the first DNS server. The processing module 902 is used to enable the transceiver module 901 to send a response message to the branch point BP device according to the forwarding rule information. The forwarding rule information is used to instruct the first PSA network element to send a data packet with a destination address of the second address to the BP device; the data packet includes the response information.

[0258] In one possible design, the transceiver module 901 is used to receive forwarding rule information from the session management function SMF network element.

[0259] In one possible design, the transceiver module 901 is used to receive response information to the DNS request information from the first DNS server through a tunnel between the first PSA network element and the first DNS server.

[0260] Among them, 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.

[0261] It should be understood that the processing module 902 in the embodiment of the present application can be implemented by a processor or a processor-related circuit component, and the transceiver module 901 can be implemented by a transceiver or a transceiver-related circuit component.

[0262] Optionally, the sending device 900 for the domain name system request may further include a storage module 903 for storing program codes and data of the device 900 . The data may include but is not limited to original data or intermediate data.

[0263] In one possible manner, the processing module 902 may be a processor or a controller, such as a central processing unit (CPU), a general-purpose processor, a digital signal processing (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor may also be a combination that implements a computing function, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like. The transceiver module 901 may be a transceiver, a transceiver circuit or a communication interface, and the like. The storage module 903 may be a memory.

[0264] In a possible manner, when the processing module 902 is a processor, the transceiver module 901 is a communication interface, and the storage module 903 is a memory, the structure of the sending device of the domain name system request involved in the embodiment of the present application can be: Fig.10 shown.

[0265] Fig.10 A simplified schematic diagram of a possible design structure of a sending device for domain name system request involved in an embodiment of the present application is shown. The sending device 1000 for domain name system request includes: a processor 1002, a communication interface 1003, and a memory 1001. Optionally, the sending device 1000 for domain name system request may also include a bus 1004. Among them, the communication interface 1003, the processor 1002 and the memory 1001 can be interconnected through the bus 1004. The bus 1004 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 1004 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.10 The fact that only one line is used in the diagram does not mean that there is only one bus or only one type of bus.

[0266] It will be appreciated by those skilled in the art that in the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product. A computer program product includes one or more computer instructions. When a computer program instruction is loaded and executed on a computer, a process or function according to an embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. Computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. A computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated therein. Available media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, digital video discs (DVDs)), or semiconductor media (eg, solid state disks (SSDs)).

[0267] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical or other forms.

[0268] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network devices (such as terminal devices). Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0269] In addition, each functional module in each embodiment of the present application can be integrated into one processing module, or each functional module can exist independently, or two or more modules can be integrated into one module. The above integrated modules can be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0270] Through the description of the above implementation methods, the technicians in the relevant field can clearly understand that the present application can be implemented by means of software plus necessary general hardware, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, hard disk or optical disk, etc., and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0271] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application shall be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for sending a domain name system DNS request, characterized in that: include: The terminal device determines the address of the first DNS server corresponding to the first application; The terminal device determines, according to the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server, a first address of the terminal device corresponding to a first packet data unit session anchor PSA network element, and the PSA network element corresponds to the first DNS server; The terminal device sends DNS request information, where the DNS request information includes an identifier of the first application, an address of the first DNS server, and a first address of the terminal device.

2. The method according to claim 1, characterized in that The method further comprises: The terminal device receives the address of the first DNS server and the address of the terminal device corresponding to the address of the first DNS server from the session management function SMF network element.

3. The method according to claim 1 or 2, characterized in that: The terminal device determines the address of a first DNS server corresponding to the first application, including: The terminal device receives the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application from the SMF network element; The terminal device determines the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application.

4. The method according to claim 3, characterized in that The identifier of the first application corresponds to a plurality of DNS servers, and the terminal device determines the address of the first DNS server according to the identifier of the first application and the address of the DNS server corresponding to the identifier of the first application, including: The terminal device determines the first DNS server that satisfies a preset policy from the multiple DNS servers; The preset strategy includes at least one of the following: The priority of the first DNS server satisfies a priority condition among the priorities of the multiple DNS servers; The distance between the first DNS server and the terminal device satisfies a spacing distance condition.

5. A device for sending a domain name system DNS request, characterized in that: include: A unit for executing each step according to any one of claims 1 to 4.

6. A device for sending a domain name system DNS request, characterized in that: include: A processor is used to call a program in a memory so that the device for sending a domain name system DNS request executes the method for sending a domain name system DNS request according to any one of claims 1 to 4.

7. A device for sending a domain name system DNS request, characterized in that: include: A processor and an interface circuit, wherein the interface circuit is used to communicate with other devices, and the processor is used to execute the method for sending a domain name system DNS request according to any one of claims 1 to 4.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program, and when the program is called by a processor, the method for sending a domain name system DNS request according to any one of claims 1 to 4 is executed.

9. A computer program product, comprising a program, characterized in that: When the program is called by a processor, the method for sending a domain name system DNS request according to any one of claims 1 to 4 is executed.

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