Communication method, device and system

Abstract

The embodiment of the invention provides a communication method, device and system. The method comprises the steps that a first network element receives a first domain name resolution request from terminal equipment, the first domain name resolution request is used for requesting to resolve an IP address corresponding to a domain name requested to resolve by the terminal equipment, and the IP address is used for the terminal equipment to request to access an application corresponding to the IP address; the first domain name resolution request carries a domain name requested to be resolved by the terminal equipment and an application label indication, the application label indication is used for indicating a deployment state of an application requested to be accessed by the terminal equipment, and the deployment state comprises whether the application is deployed on a satellite; and inquiring the IP address corresponding to the domain name according to the application label indication. Through the technical scheme provided by the invention, the time delay of application access of the terminal equipment in an NTN communication scene can be reduced.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a communication method, apparatus and system. Background Technology

[0002] The Domain Name System (DNS) is a distributed database used to map domain names to internet protocol (IP) addresses. The process of obtaining the IP address corresponding to a hostname (i.e., the fully qualified domain name) is called domain name resolution (or hostname resolution).

[0003] Before a terminal device initiates a Hypertext Transfer Protocol (HTTP) request / application access to an application server (AS), the network can first convert the application server's domain name / Uniform Resource Locator (URL) / hostname into an IP address. This process is known as DNS resolution. Specifically, the terminal device sends a DNS resolution request to a DNS server, which then sends the resolved IP address back to the terminal device. The terminal device can then initiate a Transmission Control Protocol (TCP) connection to the application server corresponding to that IP address.

[0004] However, for non-terrestrial networks (NTNs), such as satellite communications, application servers may be deployed on satellites, on the ground, or on a combination of both depending on the application strategy. How terminal devices access applications in NTN communication scenarios is a problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a communication method, apparatus, and system to offer an optimized solution for application access by terminal devices in an NTN communication scenario.

[0006] Firstly, embodiments of this application provide a communication method. This method can be applied to a first network element (e.g., a non-terrestrial local DNS server, LDNS-NT), a device within the first network element (e.g., a chip, a chip system, or a circuit), or a device compatible with the first network element. The following description uses an application to a first network element as an example. This method provides an optimized solution for application access by a terminal device in an NTN communication scenario. The first network element can be deployed on a satellite. The method can include: the first network element receiving a first domain name resolution request from a terminal device. The first domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. This IP address is used by the terminal device to request access to the application corresponding to the IP address. The first domain name resolution request carries the domain name requested by the terminal device and an application tag indication. This application tag indication indicates the deployment status of the application requested by the terminal device, including whether the application is deployed on the satellite. The method also involves querying the IP address corresponding to the domain name based on the application tag indication and the domain name.

[0007] For application servers deployed on satellites, research revealed that because DNS servers prioritize querying the locally cached IP address of the application server, they may resolve the satellite-deployed application server's IP address to the IP address of the previously accessed ground-based application server, thus increasing the latency of application access from terminal devices. Therefore, reducing the latency of application access from terminal devices in NTN communication scenarios is an urgent problem to be solved.

[0008] Unlike other scenarios where the first network element prioritizes querying the IP address of the application server in its local cache, potentially resolving the IP address of the application server deployed on the satellite to the IP address of the previous ground application server, thus increasing latency for terminal device application access, this embodiment allows the first network element to select an application server based on the application's deployment distribution (e.g., whether it is deployed on a satellite) using the application tag indication in the received first domain name resolution request. If the application requested by the terminal device is deployed on a satellite, the application server on the satellite can be prioritized to serve the terminal device, thereby reducing latency for terminal device application access in NTN communication scenarios.

[0009] In one possible implementation, querying the IP address corresponding to the domain name based on the application tag indication and the domain name includes: querying whether the domain name and the application tag indication match a local cached record; if they match, sending a domain name resolution result corresponding to the domain name to the terminal device, the domain name resolution result including the IP address corresponding to the domain name; or, if they do not match, sending a third domain name resolution request to a second network element, wherein the second network element is deployed on the ground, the third domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device, the IP address is used by the terminal device to request access to the application corresponding to the IP address, and the third domain name resolution request carries the domain name requested by the terminal device and the application tag indication carried in the first domain name resolution request. Through the embodiments of this application, the first network element can match the IP address corresponding to the domain name requested for resolution by the terminal device based on the application tag indication and the domain name and local cache records. For example, it first queries the local DNS cache records to see if the IP address corresponding to the domain name requested for resolution by the terminal device (i.e., the IP address corresponding to the application requested for access by the terminal device) exists in the local DNS cache records. If it exists (i.e., if it matches), the IP address can be sent to the terminal device. If it does not exist (i.e., if it does not match), it means that the application server of the application is not deployed on the satellite. At this time, the first network element can forward the first domain name resolution request to the second network element deployed on the ground (i.e., send the third domain name resolution request to the second network element) to request the second network element to query the IP address corresponding to the domain name requested for resolution by the terminal device. By selecting the appropriate application server for the terminal device based on the distribution of application deployment, the latency of the terminal device accessing the application in the NTN communication scenario can be reduced.

[0010] In one possible implementation, before sending a third domain name resolution request to the second network element in the event of a mismatch, the communication method may further include: querying whether the satellite where the first network element is located has a valid feeder connection to the ground; if so, sending a third domain name resolution request to the second network element; or, if not, sending a DNS resolution response to the terminal device. Through this embodiment, before forwarding the domain name resolution request to the second network element deployed on the ground, the first network element can first query whether there is a valid feeder connection to the ground. If a valid feeder connection exists, the forwarding of the domain name resolution request is then executed. If no valid feeder connection exists, the terminal device can be promptly notified of the DNS resolution response, thereby saving signaling overhead.

[0011] In one possible implementation, the DNS resolution response includes the reason for the DNS resolution failure and / or suggested information. Through the embodiments of this application, in the absence of a valid feeder connection, the first network element can promptly notify the terminal device to change the object of the requested domain name resolution (e.g., suggest that the terminal device change the DNS resolution server address or switch to terrestrial network for DNS resolution), thereby reducing the latency of application access by the terminal device.

[0012] In one possible implementation, receiving the first domain name resolution request from the terminal device includes receiving the first domain name resolution request from the terminal device via a user plane function (UPF). A UPF can be understood as a network element; in some embodiments of this application, the UPF is deployed in a satellite.

[0013] In one possible implementation, in the first domain name resolution request, the application tag indicates that it is located after the domain name that the terminal device is requesting to resolve.

[0014] Secondly, embodiments of this application provide a communication method. This method can be applied to a UPF, or to a device within the UPF (e.g., a chip, a chip system, or a circuit), or to a device compatible with the UPF. The following description uses an application to a UPF as an example. The method may include: the UPF receiving a second domain name resolution request from a terminal device. The second domain name resolution request carries a domain name that the terminal device requests to resolve. The second domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. This IP address is used by the terminal device to request access to the application corresponding to the IP address. The method further includes: determining an application tag indication based on the second domain name resolution request. The application tag indication is used to indicate the deployment status of the application that the terminal device requests to access, including whether the application is deployed on a satellite.

[0015] In this embodiment, the UPF can determine the application tag indication and include it in the domain name resolution request sent to the first network element. This allows the first network element to select an application server based on the application's deployment distribution (e.g., whether it is deployed on a satellite). If the application requested by the terminal device is deployed on a satellite, the application server on the satellite can be preferentially selected to serve the terminal device, thereby reducing the latency of application access by the terminal device in NTN communication scenarios.

[0016] It should be understood that the implementing entity of the second aspect can be UPF, the specific content of the second aspect corresponds to the content of the first aspect, and the corresponding features of the second aspect and the beneficial effects achieved can be referred to the description of the first aspect. To avoid repetition, detailed descriptions are appropriately omitted here.

[0017] In one possible implementation, determining the application tag indication based on the second domain name resolution request includes: obtaining application subscription data and / or user plane forwarding rule information; determining the application tag indication based on the application subscription data and / or user plane forwarding rule information; the application tag indication is used to indicate the deployment status of the application requested by the terminal device, the deployment status including whether the application is deployed on the satellite.

[0018] In one possible implementation, the communication method may further include: sending a first domain name resolution request to a first network element, the first domain name resolution request being used to request the resolution of the IP address corresponding to the domain name requested by the terminal device, the first domain name resolution request carrying the domain name requested by the terminal device and the application tag indication, the first network element being deployed on a satellite.

[0019] In one possible implementation, in the first domain name resolution request, the application tag indicates that it is located after the domain name that the terminal device is requesting to resolve.

[0020] Thirdly, embodiments of this application provide a communication method that can be applied to a second network element (e.g., a local DNS-terrestrial server (LDNS-T) and / or a ground dispatch center), a device in the second network element (e.g., a chip, a chip system, or a circuit), or a device that can be matched and used with the second network element. The following description uses an application to a second network element as an example. The method may include: a second network element receiving a third domain name resolution request, the third domain name resolution request carrying the domain name requested for resolution by the terminal device, an application tag indicator, and the identifier of a UPF and / or firewall (FW), wherein the UPF and / or FW is the UPF and / or FW that received the second domain name resolution request from the terminal device; wherein the third domain name resolution request is used to request resolution of the IP address corresponding to the domain name requested for resolution by the terminal device, the IP address is used by the terminal device to request access to the application corresponding to the IP address, the application tag indicator is used to indicate the deployment status of the application requested for access by the terminal device, the deployment status includes whether the application is deployed on a satellite; determining the ground gateway location corresponding to the UPF and / or FW according to the mapping relationship between the UPF and / or FW and the ground gateway location and the identifier of the UPF and / or FW; determining the application server corresponding to the application requested for access by the terminal device according to the ground gateway location corresponding to the UPF and / or FW.

[0021] The second network element can determine the location of the ground gateway corresponding to the UPF and / or FW based on the identifier of the UPF and / or FW carried in the domain name resolution request and the mapping relationship between the UPF and / or FW and the location of the ground gateway. It can also schedule and match based on the geographical location information of the ground gateway to find the IP address of the application server closest to the ground gateway, thereby determining the application server that provides services to the terminal device and reducing the latency of terminal device application access in NTN communication scenarios.

[0022] It should be understood that the implementing entity of the third aspect can be the second network element, the specific content of the third aspect corresponds to the content of the first aspect, and the corresponding features of the third aspect and the beneficial effects achieved can be referred to the description of the first aspect. To avoid repetition, detailed descriptions are appropriately omitted here.

[0023] In one possible implementation, the communication method may further include: obtaining the mapping relationship between the UPF and / or FW and the location of the ground gateway.

[0024] In one possible implementation, the communication method may further include: sending a domain name resolution result corresponding to a domain name to a terminal device, the domain name resolution result including the IP address corresponding to the domain name.

[0025] Fourthly, embodiments of this application provide a communication device, which can be a first network element or a device within the first network element (e.g., a chip, a chip system, or a circuit).

[0026] The beneficial effects can be found in the description of the first aspect, and will not be repeated here. The device has the function of implementing the behavior described in the method example of the first aspect above. This function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described function.

[0027] In one possible implementation, the communication device may include:

[0028] The transceiver unit is used to receive a first domain name resolution request from a terminal device. The first domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The IP address is used by the terminal device to request access to the application corresponding to the IP address. The first domain name resolution request carries the domain name requested by the terminal device and an application tag indicator. The application tag indicator is used to indicate the deployment status of the application requested by the terminal device. The deployment status includes whether the application is deployed on the satellite.

[0029] The processing unit is used to query the IP address corresponding to the domain name based on the application tag indication and the domain name.

[0030] In one possible implementation, the processing unit queries the IP address corresponding to the domain name based on the application tag indication and the domain name, specifically for: querying whether the domain name and the application tag indication match the local cache record;

[0031] In the event of a match, the transceiver unit is also configured to send the domain name resolution result corresponding to the domain name to the terminal device, the domain name resolution result including the IP address corresponding to the domain name; or,

[0032] In the event of a mismatch, the transceiver unit is also used to send a third domain name resolution request to the second network element, wherein the second network element is deployed on the ground, and the third domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The IP address is used by the terminal device to request access to the application corresponding to the IP address. The third domain name resolution request carries the domain name requested by the terminal device and the application tag indication carried in the first domain name resolution request.

[0033] In one possible implementation, before the transceiver unit sends a third domain name resolution request to the second network element in the event of a mismatch, the processing unit is also used to query whether the satellite where the first network element is located has a valid feeder connection to the ground.

[0034] If so, the transceiver unit is also used to send third-domain name resolution requests to the second network element; or,

[0035] If not, the transceiver unit is also used to send DNS resolution responses to the terminal device.

[0036] In one possible implementation, the DNS resolution response includes the reason for the DNS resolution failure and / or suggested information.

[0037] In one possible implementation, the transceiver unit receives a first domain name resolution request from the terminal device, specifically for: receiving the first domain name resolution request from the terminal device via UPF.

[0038] In one possible implementation, in the first domain name resolution request, the application tag indicates that it is located after the domain name that the terminal device is requesting to resolve.

[0039] Fifthly, embodiments of this application provide a communication device, which may be a UPF or a device within a UPF (e.g., a chip, a chip system, or a circuit).

[0040] The beneficial effects can be found in the description of the second aspect, and will not be repeated here. The device has the function of implementing the behavior described in the method example of the second aspect above. This function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described function.

[0041] In one possible implementation, the communication device may include:

[0042] The transceiver unit is used to receive a second domain name resolution request from a terminal device. The second domain name resolution request carries the domain name that the terminal device requests to resolve. The second domain name resolution request is used to request the resolution of the IP address corresponding to the domain name that the terminal device requests to resolve. The IP address is used by the terminal device to request access to the application corresponding to the IP address.

[0043] The processing unit is used to determine the application tag indication based on the second domain name resolution request. The application tag indication is used to indicate the deployment status of the application requested by the terminal device, including whether the application is deployed on the satellite.

[0044] In one possible implementation, the processing unit determines the application tag indication based on the second domain name resolution request, specifically for obtaining application subscription data and / or user plane forwarding rule information; the application tag indication is used to indicate the deployment status of the application requested by the terminal device, including whether the application is deployed on the satellite.

[0045] In one possible implementation, the transceiver unit is further configured to send a first domain name resolution request to the first network element. The first domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The first domain name resolution request carries the domain name requested by the terminal device and the application tag indication. The first network element is deployed on a satellite.

[0046] In one possible implementation, in the first domain name resolution request, the application tag indicates that it is located after the domain name that the terminal device is requesting to resolve.

[0047] Sixthly, embodiments of this application provide a communication device, which can be a second network element or a device within the second network element (e.g., a chip, a chip system, or a circuit).

[0048] The beneficial effects can be found in the description of the third aspect, and will not be repeated here. The device has the function of implementing the behavior described in the method example of the third aspect above. This function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described function.

[0049] In one possible implementation, the communication device may include:

[0050] The transceiver unit is used to receive a third domain name resolution request. The third domain name resolution request carries the domain name requested by the terminal device for resolution, the application tag indicator, and the identifiers of UPF and / or FW. The UPF and / or FW are the UPF and / or FW of the second domain name resolution request received by the terminal device. The third domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The IP address is used by the terminal device to request access to the application corresponding to the IP address. The application tag indicator is used to indicate the deployment status of the application requested by the terminal device. The deployment status includes whether the application is deployed on the satellite.

[0051] The processing unit is used to determine the ground gateway location corresponding to the UPF and / or FW based on the mapping relationship between the UPF and / or FW and the ground gateway location and the identifier of the UPF and / or FW.

[0052] The processing unit is also used to determine the application server corresponding to the application requested by the terminal device based on the location of the ground gateway corresponding to the UPF and / or FW.

[0053] In one possible implementation, the processing unit is also used to obtain the mapping relationship between the UPF and / or FW and the location of the ground gateway.

[0054] In one possible implementation, the transceiver unit is also used to send the domain name resolution result corresponding to the domain name to the terminal device, which includes the IP address corresponding to the domain name.

[0055] In a seventh aspect, a communication device is provided. This device may be a first network element or a device within the first network element (e.g., a chip, a chip system, or a circuit). The device may include a processor, a memory, an input interface, and an output interface. The input interface is used to receive information from other communication devices outside the device, and the output interface is used to output information to other communication devices outside the device. The processor invokes a computer program stored in the memory to execute the communication method provided in the first aspect or any embodiment of the first aspect.

[0056] Eighthly, a communication device is provided, which may be a UPF or a device within a UPF (e.g., a chip, a chip system, or a circuit). The device may include a processor, a memory, an input interface, and an output interface. The input interface is used to receive information from other communication devices outside the device, and the output interface is used to output information to other communication devices outside the device. The processor invokes a computer program stored in the memory to execute the communication method provided in the second aspect or any embodiment of the second aspect.

[0057] A ninth aspect provides a communication device, which may be a second network element or a device within a second network element (e.g., a chip, a chip system, or a circuit). The device may include a processor, a memory, an input interface, and an output interface. The input interface is used to receive information from other communication devices outside the device, and the output interface is used to output information to other communication devices outside the device. The processor invokes a computer program stored in the memory to execute the communication method provided in the third aspect or any embodiment of the third aspect.

[0058] In a tenth aspect, embodiments of this application provide a communication system comprising at least one first network element, at least one UPF, and at least one second network element. When at least one of the aforementioned first network element, at least one of the aforementioned UPF, and at least one of the aforementioned second network elements are running in the system, they are used to execute any of the communication methods described in the first aspect, any of the second aspect, and any of the third aspect.

[0059] Eleventhly, embodiments of this application provide a computer-readable storage medium storing computer instructions that, when the computer program or computer instructions are executed, cause the methods described in the first aspect and any possible implementation thereof, the second aspect and any possible implementation thereof, and the third aspect and any possible implementation thereof to be performed.

[0060] In a twelfth aspect, embodiments of this application provide a computer program product including executable instructions, which, when run on a communication device, causes the methods described in the first aspect and any possible implementation thereof, the second aspect and any possible implementation thereof, and the third aspect and any possible implementation thereof to be executed.

[0061] In a thirteenth aspect, embodiments of this application provide a communication device, which includes a processor and may further include a memory, for implementing the methods described in the first aspect and any possible implementation thereof, the second aspect and any possible implementation thereof, and the third aspect and any possible implementation thereof. The device may be a chip system, which may be composed of chips or may include chips and other discrete devices. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0063] Figure 1 This is a schematic diagram of a non-terrestrial communication system provided in an embodiment of this application;

[0064] Figure 2This is a schematic diagram of a 5G satellite communication system architecture provided in an embodiment of this application;

[0065] Figure 3 This is a schematic diagram of a satellite DNS architecture provided in an embodiment of this application;

[0066] Figure 4 This is a schematic diagram of the structure of an LDNS server provided in an embodiment of this application;

[0067] Figure 5 This is a schematic diagram of a satellite DNS architecture provided in an embodiment of this application;

[0068] Figure 6 This is an interactive schematic diagram of a communication method provided in an embodiment of this application;

[0069] Figure 7 This is a schematic diagram of an iterative query provided in an embodiment of this application;

[0070] Figure 8 and Figure 9 This is a schematic diagram of the structure of a possible communication device provided in the embodiments of this application. Detailed Implementation

[0071] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0072] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0073] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0074] In this application, "at least one (item)" means one or more, "more than one" means two or more, "at least two (items)" means two or three or more, and "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0075] In this application, "sending information" can be understood as one device sending information to another device, or it can also be understood as one logical module within a device sending information to another logical module. For example, "access network device sending information" can be understood as the access network device sending information to another device (such as a terminal), or it can be understood as logical module 1 in the access network device sending information to logical module 2 in the access network device.

[0076] In this application, "receiving information" can be understood as one device receiving information from another device, or it can also be understood as a logical module within a device receiving information from another logical module. For example, "access network device receiving information" can be understood as the access network device receiving information from another device (such as a terminal), or it can be understood as logical module 1 in the access network device receiving information from logical module 2 in the access network device.

[0077] In this application, "sending information to... (e.g., a terminal)" can be understood as the destination of the information being the terminal. This can include sending information to the terminal directly or indirectly. "Receiving information from... (e.g., a terminal)" or "receiving information from... (e.g., a terminal)" can be understood as the source of the information being the terminal, and can include receiving information from the terminal directly or indirectly. Information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be understood in a similar way, and will not be elaborated further here.

[0078] To better understand the embodiments of this application, the system architecture involved in the embodiments of this application will be described first below:

[0079] This application's embodiments can be applied to communication systems such as satellite communication, including satellite base stations, ground stations, and terminal device network elements. The satellite base station provides communication services to the terminal device, transmitting downlink data to the terminal device. This data is encoded using channel coding, and the channel-coded data is then modulated by constellation before being transmitted to the terminal device. The terminal device transmits uplink data to the satellite base station, which can also be encoded using channel coding. The encoded data is then modulated by constellation before being transmitted to the satellite base station. The wireless communication system may include one or more network devices and one or more terminal devices.

[0080] The following is based on Figure 1 The system architecture shown is illustrated as an example, and the communication method provided in this application embodiment can be applied to NTN communication systems. Figure 1 As shown, the NTN communication system includes network device 101 and terminal device 102.

[0081] The terminal device 102 can also be referred to as user equipment (UE), mobile station (MS), mobile terminal (MT), etc., or as a device used to provide voice or data connectivity to users, or as an Internet of Things (IoT) device. For example, terminal devices include handheld devices with wireless connectivity, vehicle-mounted devices, etc. Currently, terminal devices can include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices (such as smartwatches, smart bracelets, pedometers, etc.), in-vehicle devices (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point-of-sale (POS) machines, customer-premises equipment (CPE), wireless terminal devices in industrial control, smart home devices (such as refrigerators, televisions, air conditioners, electricity meters, etc.), smart robots, robotic arms, workshop equipment, wireless terminal devices in autonomous driving, wireless terminal devices in telemedicine, wireless terminal devices in smart grids, wireless terminal devices in transportation safety, wireless terminal devices in smart cities, or wireless terminal devices in smart homes, and flying equipment (such as smart robots, hot air balloons, drones, airplanes), etc. The terminal device can also be other devices with terminal device functions. For example, the terminal device can also be a device that performs the terminal device function in D2D communication.

[0082] The embodiments of this application do not limit the device form of the terminal device. The device used to implement the function of the terminal device can be the terminal device itself; it can also be a device that supports the terminal device in implementing the function, such as a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In the embodiments of this application, the chip system can be composed of chips or can include chips and other discrete components.

[0083] Network device 101 can also be referred to as a satellite, high-altitude platform, high-altitude aircraft, or satellite base station. Network device 101 provides communication services to terminal device 102, and can also connect to core network equipment. The network device is used to help terminal devices achieve wireless access.

[0084] In one possible scenario, network equipment can be a base station, an evolved NodeB (eNodeB), a transmitting and receiving point (TRP), a transmitting point (TP), a next-generation NodeB (gNB), a next-generation base station in a 6th-generation (6G) mobile communication system, a base station in a future mobile communication system, a satellite, an integrated access and backhaul (IAB) node, or network equipment in a mobile switching center non-terrestrial network (NTN) communication system, i.e., it can be deployed on a high-altitude platform or satellite, etc. Network equipment can be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a radio controller in a CRAN scenario. Network equipment can also be a device that functions as a base station in device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, drone communication, or machine-to-machine (M2M) communication. Optionally, network equipment can also be a server, wearable device, vehicle or in-vehicle equipment, etc. For example, network devices in vehicle-to-everything (V2X) technology can be roadside units (RSUs).

[0085] All or part of the functions of the network device in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (such as a cloud platform). The network device in this application can also be a logical node, logical module, or software capable of implementing all or part of the functions of a network device.

[0086] In another possible scenario, multiple network devices collaborate to assist terminal devices in achieving wireless access, with each network device performing a portion of the base station's functions. For example, network devices can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs). CUs and DUs can be separate entities or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio equipment or radio units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs). It is understood that network devices can be CU nodes, DU nodes, or devices comprising both CU and DU nodes. Furthermore, CUs can be classified as network devices in the access network (RAN) or the core network (CN), without limitation.

[0087] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0088] Taking 5G as an example, a 5G satellite communication system architecture is as follows: Figure 2 As shown, ground terminal equipment accesses the network via the 5G New Radio interface. 5G base stations are deployed on satellites and connected to the ground core network via wireless links. Simultaneously, wireless links exist between satellites to facilitate signaling interaction and user data transmission between base stations. Figure 2 The devices and interfaces described are as follows:

[0089] 5G Core Network: This includes applications such as user access control, mobility management, session management, user security authentication, and billing. It consists of multiple functional units, which can be divided into control plane and data plane functional entities. The Access and Mobility Management Unit (AMF) is responsible for user access management, security authentication, and mobility management. The User Plane Unit (UPF) is responsible for managing user plane data transmission and traffic statistics. The Session Management Function (SMF) is mainly used for session management in the mobile network, such as session establishment, modification, and release.

[0090] Ground station: Responsible for forwarding signaling and application data between satellite base stations and the 5G core network.

[0091] 5G New Radio: The wireless link between terminal devices and base stations.

[0092] Xn interface: The interface between 5G base stations, mainly used for signaling interactions such as handover.

[0093] NG interface: The interface between 5G base stations and 5G core networks, mainly used for exchanging non-access stratum (NAS) signaling of the core network and user application data.

[0094] In this embodiment, the form of the network device is not limited. The device used to implement the function of the network device can be the network device itself, or it can be a device that supports the network device in implementing the function, such as a chip system. The device can be installed in the network device or used in conjunction with the network device.

[0095] The following description of the technical solutions provided in the embodiments of this application uses a satellite as an example to illustrate the function of a network device. It is understood that when the solutions provided in the embodiments of this application are applied to a terrestrial communication system, the actions performed by the satellite can be applied to a base station or network device for execution. Furthermore, the aforementioned satellite can be a geostationary satellite, a non-geostationary satellite, an artificial satellite, a low-Earth orbit satellite, a medium-Earth orbit satellite, or a high-Earth orbit satellite, etc., and this application does not specifically limit the types of satellites described.

[0096] To facilitate understanding of the content of this solution, some terms used in the embodiments of this application will be explained below, so that those skilled in the art can understand them. This part is only for the purpose of understanding and should not be regarded as a specific limitation of this application.

[0097] 1. Domain Name Server

[0098] A DNS (Domain Name Server) is a server that translates domain names into their corresponding IP addresses. It acts as a router, responsible for converting user-understandable domain names into IP addresses that computers can understand. The DNS maintains a table of domain names and their corresponding IP addresses to resolve the domain names of messages. A domain name is the name of a computer or group of computers on the Internet, used to identify the computer's electronic location (and sometimes geographical location) during data transmission. A domain name consists of a string of names separated by dots, usually including the organization name, and always includes a two- or three-letter suffix to indicate the type of organization or the country or region where the domain is located.

[0099] 2. Recursive server

[0100] It is responsible for accepting user queries for any domain name and returning the results to the user. A recursive server can cache the results to avoid repeated upward queries.

[0101] In the process of domain name resolution, recursive and iterative resolution is performed by the domain name server. A recursive domain name server is a server that completely resolves domain names. When a user sends a domain name resolution request to a recursive server, the recursive server sends a request to the root name server, and then queries down the hierarchy until it finds the required domain name resolution information, and then returns the result to the user. This process is similar to asking a series of questions until the final answer is obtained.

[0102] 3. Iterative Domain Name Server

[0103] Iterative name servers delegate some of the name resolution tasks to other servers. When a user sends a resolution request to an iterative server, the iterative server queries the root name server. However, the root name server only tells the iterative server which server to query next, without providing the final resolution result. The iterative server then sends a request to the specified next-level server. This process may iterate multiple times until the final resolution result is obtained, and then the result is returned to the user.

[0104] The main difference between recursive and iterative name servers lies in the allocation of responsibility during the resolution process. A recursive server handles all the resolution work from the root server to the final target server, while an iterative server is only responsible for forwarding the resolution request to other servers and returning the final result to the user.

[0105] Recursive and iterative DNS servers each have their applicable scenarios. Recursive servers are typically used for domain name resolution requests from ordinary users because they can provide complete resolution results, and users do not need to care about the specific details of the resolution. Iterative servers, on the other hand, are often used in more advanced network configurations, such as servers of Internet Service Providers (ISPs), which need to handle a large number of resolution requests and have better control over the resolution process.

[0106] 4. Authoritative DNS Server

[0107] Authoritative DNS servers are servers that are authorized by a higher-level DNS provider to resolve domain names. They can also delegate this authority to others. For example, a .COM top-level server can authorize http: / / NS.ABC.COM as the authoritative server for the domain http: / / dns.com. http: / / NS.ABC.COM can then delegate this authority to http: / / NS.DDD.COM, making http: / / NS.DDD.COM the actual authoritative server for http: / / ABC.COM. Typically, the results of a user's domain name resolution come from authoritative DNS servers. For instance, the authoritative DNS servers for http: / / dns.com are http: / / ns1.dns.com and http: / / ns2.dns.com. Then, the specific IP address or other records of the domain can be found through http: / / ns1.dns.com.

[0108] 5. Forwarding DNS server

[0109] It is responsible for accepting user queries and returning results to the user. However, this result is not obtained through the standard domain name resolution process; instead, the result of the recursive DNS is directly forwarded to the user. It also has caching capabilities and is mainly used when there is no direct internet connection, but a connection to a recursive DNS is possible. In this case, using a forwarding DNS is more appropriate.

[0110] 6. Recursive and Iterative Queries

[0111] Recursive queries and iterative queries are two different query methods, primarily used in DNS systems, but they differ in their operation and application scenarios. Details are as follows:

[0112] Recursive query: This is typically initiated by the client (such as a user's computer or device). In this query method, the client sends a complete query request to the local DNS server, containing the domain name to be resolved. The local DNS server is responsible for querying from the root DNS server down the hierarchy to obtain the IP address corresponding to the domain name. If the domain name server cannot answer directly, it will recursively query each branch of the domain name tree, eventually returning the query result to the client. During the query process, the client will be in a completely waiting state.

[0113] Iterative queries, also known as redirection, allow other servers to return an optimal query point hint or host address when the server uses iterative queries. If this optimal query point contains the requested host address, the address information is returned; if the server cannot directly find the host address, it queries sequentially according to the hints until the requested host address is found in the server's hints. Generally, each redirection moves closer to the root server (upwards), and after finding the root name server, it searches downwards again according to the hints.

[0114] The main difference between these two query methods is that recursive queries are performed on the local DNS server, while iterative queries are performed on the root name server. In practice, recursive queries are typically used for queries from the requesting host to the local DNS server, while iterative queries are used when the local DNS server sends a query request to the root name server.

[0115] It should be understood that the definitions of the above technical terms are merely illustrative. For example, as technology continues to develop, the scope of the above definitions may also change, and the embodiments of this application are not intended to limit the scope.

[0116] First, in order to facilitate understanding of the embodiments of this application, the technical problems that this application specifically aims to solve will be further analyzed and proposed.

[0117] Before a user sends an HTTP request or accesses an application server, the network first translates the application server's domain name / URL / hostname into an IP address. This process is called DNS resolution. Once the user receives the IP address from the DNS resolution, they can initiate a TCP connection to the application server corresponding to that IP address.

[0118] The current architecture of satellite DNS is as follows Figure 3 As shown, the base station gNB, core network element UPF, and DNS cache server are deployed on the satellite. Figure 3The non-terrestrial network portion shown includes, for example, LEO (Low Earth Orbit) satellites. In the DNS resolution process, the terminal device can be viewed as a DNS client, and LDNS as a DNS server. Specifically:

[0119] 1. Terminal devices can initiate DNS resolution requests to the onboard DNS server. For example, a terminal device can initiate a DNS resolution request to the base station gNB, which will then forward the DNS resolution request to the onboard UPF.

[0120] 2. The onboard UPF can send DNS resolution requests to appropriate satellites, such as onboard DNS caching servers, according to the pre-configured satellite selection and scheduling strategy. The onboard DNS caching server can periodically access ground-based LDNS servers to obtain the latest DNS records, thus avoiding situations where application server IP addresses are unavailable or have changed.

[0121] The actual access route of the terminal device's application can be illustrated as follows: The terminal device initiates a DNS resolution request to the base station gNB, the base station gNB forwards the DNS resolution request to the on-board UPF, the on-board UPF requests DNS resolution from the ground LDNS server, and after the ground LDNS finds the IP address of the application server, it sends the IP address of the application server to the terminal device through the on-board UPF and the base station gNB.

[0122] For the LDNS server mentioned above, please refer to [link / reference]. Figure 4 , Figure 4 This is a schematic diagram of the structure of an LDNS server provided in an embodiment of this application. Figure 4 As shown, domain name resolution follows the top-down process characteristic of the DNS hierarchical structure. However, if every domain name resolution starts from the root name server, the root name server may not be able to handle massive traffic. In practical applications, most domain name resolution can be completed on local name servers (LDNS servers), which are usually managed by one or more ISPs (Internet Service Providers).

[0123] The DNS resolution under the aforementioned satellite DNS architecture may have the following technical problems:

[0124] Technical Issue 1: Application servers may be deployed on satellites, on the ground, or on demand according to application strategies. However, current DNS processing does not select the application server's IP address based on the distribution of application instances. For example, if an application instance is launched on a satellite using virtualization technology, but the local DNS record's IP resolution result is the IP address of the previous ground application server, then LDNS will prioritize querying the local cache and return the ground application server's IP address to the terminal device, increasing the latency of application access on the terminal device.

[0125] Technical Issue 2: Existing edge computing solutions used by operators involve provincially deployed LDNSs allocating application server IP addresses based on the geographical location of the UPF (User Platform Provider) accessed by the terminal device. Typically, the IP address of the server closest to the terminal device is selected to accelerate the application experience and reduce access latency. However, since UPFs are located on satellites, LDNS cannot directly map to ground-based geographical locations. This means it cannot directly match the application server's IP address based on the UPF address, thus increasing the latency of application access from the terminal device.

[0126] Therefore, how to reduce the latency of terminal device application access in NTN communication scenarios is an urgent technical problem to be solved.

[0127] The technical problem to be solved by the embodiments of this application is to reduce the latency of terminal device application access in NTN communication scenarios.

[0128] Based on the above, this application proposes a communication method, which will be described below through various embodiments. It should be understood that, in the various embodiments of this application, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments are consistent and can be mutually referenced. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships. These methods can be used in combination. The technical solutions provided by this application are not limited to the processes described below. Furthermore, the scenario descriptions in the embodiments of this application are merely illustrative and do not limit the solutions of the embodiments of this application to only the described scenarios; they are also applicable to scenarios with similar problems.

[0129] First, the network architecture of the embodiments of this application will be described. Please refer to... Figure 5 , Figure 5 This is a schematic diagram of a satellite DNS architecture provided in an embodiment of this application. Compared to Figure 3 The current satellite DNS architecture is shown below. Figure 5 The satellite DNS architecture shown can accommodate the addition of an LDNS-NT server deployed on a satellite. The structure of this LDNS-NT server can be consistent with... Figure 4 The LDNS server shown has the same structure, that is, it can include a caching server and a recursive server, and the functions it implements can also be the same. Figure 4 The LDNS servers shown are the same. Optionally, the DNS resolution records stored on the LDNS-NT server can be periodically synchronized by the LDNS-T server to the on-board LDNS-NT server, or the on-board LDNS-NT server can proactively and periodically send update requests to the ground-based LDNS-T server.

[0130] like Figure 5As shown, the architecture of satellite DNS can include terminal equipment (such as UE), access network equipment (such as gNB onLEO), core network element UPF, LDNS-NT server, LDNS-T server, ground dispatch center, and application server. The access network equipment, core network element UPF, and LDNS-NT server are deployed on the satellite, while the terminal equipment, LDNS-T server, and ground dispatch center are deployed on the ground. The application server may be deployed on the satellite, on the ground, or as needed based on application policies, on both the satellite and the ground. For example, the application server deployed on the satellite might correspond to IP address 1, while the application server deployed on the ground might correspond to IP address 2.

[0131] It is understandable that if the satellites deployed by the access network equipment, core network element UPF, and LDNS-NT server belong to the same constellation, there should be an ISL inter-satellite link between them; if they do not belong to the same constellation, there should be at least one inter-satellite link between the constellations, that is, the inter-satellite routes between satellites are reachable.

[0132] In combination with the above Figure 5 The network architecture is described below, along with a communication method provided by an embodiment of this application. It is understood that this application uses a first network element, a UPF, and a second network element as examples to illustrate the interaction, but this application does not limit the execution entities of the interaction. For example, the first network element in the embodiments of this application (as described in the corresponding embodiments below) could be... Figure 5 The terminal device in the LDNS-NT server shown, and the method executed by the LDNS-NT server in this application, can also be executed by a module (e.g., a chip, chip system, or processor) applied to the LDNS-NT server, or by a logical node, logical module, or software capable of implementing all or part of the LDNS-NT server functions. The UPF in this embodiment can be... Figure 5 The UPF in the network architecture shown, and the methods executed by the UPF in this application, can also be executed by a module applied to the UPF (e.g., a chip, chip system, or processor), or by a logical node, logical module, or software capable of implementing all or part of the UPF functions. The second network element in this embodiment can be... Figure 5 The LDNS-T server in the network architecture shown, and the methods executed by the LDNS-T server in this application, can also be executed by modules (e.g., chips, chip systems, or processors) applied to the LDNS-T server, or by logical nodes, logical modules, or software capable of implementing all or part of the LDNS-T server functions. The satellite can be a geostationary satellite, a non-geostationary satellite, an artificial satellite, a low-Earth orbit satellite, a medium-Earth orbit satellite, or a high-Earth orbit satellite, etc., and this application does not specifically limit the types of satellites.

[0133] Please see Figure 6 , Figure 6 This is an interactive schematic diagram of a communication method provided in an embodiment of this application. For example... Figure 6 As shown, the communication method may include at least the following steps.

[0134] S601: The terminal device sends a second domain name resolution request to the UPF, which carries the domain name that the terminal device requests to resolve. Correspondingly, the UPF receives the second domain name resolution request from the terminal device.

[0135] Terminal devices can initiate application-layer domain name resolution requests, that is, request the network side to obtain the IP address corresponding to the domain name requested by the terminal device in the domain name resolution request. For example, the terminal device sends a second domain name resolution request to the UPF. This second domain name resolution request can be used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. This IP address is used by the terminal device to request access to the application corresponding to the IP address. The second domain name resolution request carries the domain name requested by the terminal device. Optionally, the second domain name resolution request may also carry the source address, destination address, and the ID of the application requested by the terminal device. For example, the source address is the address of the terminal device, and the destination address is the address of the UPF or the IP address of the operator's LDNS server. For example, the address can be an IP address, a Media Access Control (MAC) address, etc., where the IP address can be an IPv4 address or an IPv6 address, or other IP addresses for future wireless communication development.

[0136] In this application embodiment, the address can also be understood as the device identifier. For example, the identifier of the terminal device may include one or more of the following information: subscription concealed identifier (SUCI), subscription permanent identifier (SUPI), 5G globally unique temporary identity (5G GUTI), temporary mobile subscriber identity (TMSI), 5G system temporary mobile subscriber identity (5GS TMSI), generic public subscription identifier (GPSI), EPC, network identifier, and identification information indicating the application requester, etc.

[0137] For example, the application server can be an edge application server (EAS). An edge application server can be understood as an application server that is located close to the terminal device relative to the terminal device and provides services to the applications of the terminal device.

[0138] It should be noted that signaling interaction between terminal equipment and core network elements (such as UPF) can be transparently transmitted through the access network equipment RAN. Figure 6 Not illustrated in the diagram. For example, signaling interactions between terminal equipment and the UPF can be transmitted transparently through the access network equipment (RAN) or forwarded by the core network element's access and mobility management function (AMF).

[0139] S602: UPF determines the application tag instruction based on the second domain name resolution request.

[0140] After receiving a second domain name resolution request from a terminal device, the UPF can determine the application label indication based on the request. Specifically, upon receiving the second domain name resolution request, the UPF identifies the domain name in the second domain name resolution, matches and executes user plane traffic splitting rules / N4 session traffic splitting rules (packetdetectrule + forwardactionrule, which can also be understood as performing rule detection on the second domain name resolution request packet). That is, the UPF obtains application subscription data and / or user plane forwarding rule information, and can determine the application label indication based on this information. In other words, the UPF can synchronize the application's subscription data and user plane traffic splitting rules / N4 session traffic splitting rules from the terrestrial core network and include the application label indication along with the second domain name resolution request.

[0141] UPF can determine the application tag indication based on application subscription data and / or user plane forwarding rule information, and can be any of the following possible implementation methods:

[0142] The first possible implementation involves the UPF determining the application tag indication based on application subscription data. Specifically, the UPF can match the application requested by the terminal device with the application subscription data to determine the deployment status of the application requested by the terminal device, thereby determining the application tag indication.

[0143] The second possible implementation involves the UPF determining the application label indication based on user plane forwarding rule information. Specifically, the UPF can obtain user plane forwarding rule information, which can be understood as the UPF's processing rules for received data packets (such as second domain name resolution requests). The UPF then processes the received second domain name resolution request information according to this user plane forwarding rule information. For example, the user plane forwarding rule information might include: application deployment status, data packet identification, and tagging. After determining the application label indication based on the application deployment status, the UPF can add the determined application label indication to the second domain name resolution request.

[0144] A third possible implementation is that the UPF can determine the application tag indication based on application subscription data and user plane forwarding rule information. Specifically, the UPF can obtain application subscription data and user plane forwarding rule information, match the application requested by the terminal device with the application subscription data, determine the deployment status of the application requested by the terminal device, and thus determine the application tag indication. The UPF then processes the information in the received second domain name resolution request based on the user plane forwarding rule information. For example, if the user plane forwarding rule information includes identifying and tagging data packets, then after determining the application tag indication based on the application subscription data, the UPF can add the determined application tag indication to the second domain name resolution request.

[0145] The application tag indicates the deployment status of the application requested by the terminal device. For example, the deployment status may include whether the application is deployed on a satellite, and optionally, it may also include information such as the instance's load. For instance, the application tag may include "on_board" and "on_the_ground," where "on_board" indicates that the application requested by the terminal device is deployed on a satellite, and "on_the_ground" indicates that the application requested by the terminal device is deployed on the ground.

[0146] In other words, UPF can identify applications based on the application ID or domain name requested by the terminal device, and compare it with the contracted data to identify which applications are deployed on satellite and which applications are deployed on the ground.

[0147] UPF can be managed from core network elements user data management (UDM) / unified data repository (UDR). UDM can be understood as the core network element mainly responsible for managing functions such as subscription data and user access authorization, while UDR can be understood as the core network element mainly responsible for storing and retrieving data of types such as subscription data, policy data, and application data.

[0148] S603: The UPF sends a first domain name resolution request to the first network element. The first domain name resolution request carries the domain name that the terminal device requests to resolve and the application tag indication. Correspondingly, the first network element receives the first domain name resolution request from the UPF.

[0149] The first domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The first domain name resolution request can also be called a first DNS resolution request or simply a first DNS request; however, this embodiment does not limit the name of the first domain name resolution request. The domain name requested by the terminal device can also be understood as the domain name of the application server that the terminal device is requesting to resolve. The first network element can be understood as the destination network element corresponding to the IP address of the operator's LDNS server carried in the second domain name resolution request.

[0150] The UPF sending a first domain name resolution request to the first network element can also be understood as the UPF forwarding a second domain name resolution request from the terminal device to the first network element. Unlike the second domain name resolution request, which carries the domain name requested by the terminal device, the first domain name resolution request carries the domain name requested by the terminal device and an application tag indication determined by the UPF. Optionally, the first domain name resolution request may also carry the source address, destination address, and the ID of the application requested by the terminal device. For example, the source address can be the address of the UPF, and the destination address can be the address of the first network element. For a detailed description of the address, please refer to S601 above. Optionally, upon receiving the second domain name resolution request, the UPF can perform network address translation (NAT) mapping on the source address of the terminal device, for example, updating the source address to the address of the UPF.

[0151] In one possible implementation, the application label indication in the first domain name resolution request may be located after the domain name that the terminal device is requesting to resolve. In other words, in the first domain name resolution request packet, the field indicating the application label may be located after the field of the domain name that the terminal device is requesting to resolve. For example, the application label indication may be carried after the query name (the queried hostname) in the query questions section of the message format of the first domain name resolution request.

[0152] S604: The first network element queries the IP address corresponding to the domain name according to the application tag instruction.

[0153] After receiving the first domain name resolution request from the UPF, the first network element can query the IP address corresponding to the domain name based on the application tag carried in the first domain name resolution request.

[0154] Specifically, the first network element can query whether the domain name requested by the terminal device and the application tag indication match the local cache record. If they match, step S605 can be executed; otherwise, steps S606-S609 can be executed. In other words, the first network element can first query the local cache record (such as the local DNS cache record) to see if a match can be found (i.e., whether the application tag indication and the domain name requested by the terminal device can find the corresponding application server's IP address). In other words, it checks if the local DNS cache record contains the IP address corresponding to the domain name requested by the terminal device (i.e., the IP address corresponding to the application the terminal device is requesting to access). If a match is found, step S605 is executed; otherwise, steps S606-S609 are executed, recursively tracing the first domain name resolution request to the second network element on the ground to continue querying the IP address corresponding to the domain name requested by the terminal device.

[0155] Optionally, in the event of a mismatch, before executing S606-S609, the first network element can also query whether its satellite / constellation has a valid feeder connection to the ground using pre-configured ephemeris information. If so, S606-S609 can be executed; otherwise, a DNS resolution response can be sent to the terminal device. This DNS resolution response includes one or more of the following: a DNS resolution failure indication, a reason for the DNS resolution failure, and / or suggested information. The reason for the DNS resolution failure could be, for example, that DNS resolution results cannot be obtained temporarily through the satellite network. The suggested information could be, for example, suggesting that the terminal device change the DNS resolution server address or switch to a terrestrial network for DNS resolution (i.e., suggesting that the terminal device initiate a domain name resolution request to the second network element).

[0156] Understandably, S605 and S606-S609 below are optional steps that can be performed in parallel.

[0157] It should be noted that whether the DNS resolution result is obtained locally by the first network element or recursively obtained from the second network element on the ground, the following rules can be satisfied: 1) If, according to the application tag in the first domain name resolution request, the application requested by the terminal device is deployed on the satellite, then the IP address of the application server deployed on the satellite can be returned to the terminal device first (e.g., Figure 5 The application server IP address shown is 1); 2) If, according to the application tag in the first domain name resolution request, the application requested by the terminal device is not deployed on the satellite, then the IP address of the application server deployed on the ground can be returned to the terminal device first (e.g., Figure 5The application server IP address shown is 2). For example, if the application label indicates "on_board", then regardless of whether the first network element queries the local cache record or forwards the first domain name resolution request to the second network element on the ground, the first network element or the second network element will prioritize matching the IP address of the application server on the satellite for the terminal device; if the application label indicates "on_the_ground", then regardless of whether the first network element queries the local cache record or forwards the first domain name resolution request to the second network element on the ground, the first network element or the second network element will prioritize matching the IP address of the application server on the ground for the terminal device.

[0158] Based on S604, unlike the first network element which prioritizes querying the IP of the application server cached locally, the IP of the application server deployed on the satellite may be resolved to the IP of the previous ground application server, leading to increased latency for terminal device application access. In this embodiment, the first network element can select an application server based on the application deployment distribution (e.g., whether it is deployed on a satellite) indicated by the application tag in the received first domain name resolution request. If the application requested by the terminal device is deployed on a satellite, the application server on the satellite can be preferentially selected to serve the terminal device, thereby reducing the latency of terminal device application access in NTN communication scenarios.

[0159] It should be noted that the structure of the first network element may include a cache server and a recursive server. The first network element querying the IP address corresponding to the domain name requested by the terminal device according to the application tag in the first domain name resolution request can be performed by the cache server. In S606 below, the first network element sending the third domain name resolution request to the second network element can be performed by the recursive server, that is, continuing to recursively query the IP address corresponding to the domain name requested by the terminal device.

[0160] S605: The first network element sends the domain name resolution result to the terminal device, which includes the IP address corresponding to the domain name. Correspondingly, the terminal device receives the domain name resolution result from the first network element.

[0161] Optionally, if the first network element forwards the first domain name resolution request to the opposite second network element to obtain the DNS resolution result, then Figure 6 The method flow shown may also include the following steps S606-S609.

[0162] S606: The first network element sends a third domain name resolution request to the second network element. The third domain name resolution request carries at least one of the following: the domain name requested for resolution by the terminal device, an application tag indication, and an identifier of UPF and / or FW. Correspondingly, the second network element receives the third domain name resolution request from the first network element.

[0163] The first network element can forward the first domain name resolution request to the second network element on the ground to obtain the DNS resolution result. That is, the first network element sends a third domain name resolution request to the second network element. The third domain name resolution request can be used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The third domain name resolution request carries at least one of the domain name requested by the terminal device carried in the first domain name resolution request, as well as the application tag indicator, UPF and / or FW identifier (such as IP address).

[0164] After receiving a third-party domain name resolution request from the first network element, the second network element can initiate an iterative query. For details, please refer to [link to relevant documentation]. Figure 7 , Figure 7 This is a schematic diagram of an iterative query provided in an embodiment of this application. For example... Figure 7 As shown, the second network element can be a local domain name server (LDNS-T server). After receiving a third domain name resolution request, it can request DNS resolution results from the root domain name server, top-level domain name server, and authoritative domain name server in sequence. The authoritative domain name server can optionally use CNAME technology to redirect the DNS resolution request to the ground dispatch center to continue requesting and obtaining DNS resolution results.

[0165] Understandably, if one of the domain name servers obtains the DNS resolution result, then S609 can be executed.

[0166] S607: The second network element determines the location of the ground gateway corresponding to the UPF and / or FW based on the mapping relationship between the UPF and / or FW and the location of the ground gateway and the identifier of the UPF and / or FW.

[0167] For example, the LDNS-T server sends a domain name resolution request to the ground control center. This domain name resolution request may include at least one of the following: the domain name requested by the terminal device, an application label indication, and the identifier of a UPF and / or FW. Optionally, the domain name resolution request may include a source address and a destination address, for example, the source address is the address of the LDNS-T server, and the destination address is the address of the ground control center.

[0168] The ground control center can obtain the mapping relationship between UPF and / or FW and the ground gateway location, and determine the ground gateway location corresponding to the UPF and / or FW based on the identifier of the UPF and / or FW in the third-party domain name resolution request. The mapping relationship between the UPF and / or FW and the ground gateway location can be pre-configured by the operator. The identifier of the UPF and / or FW can be an identifier or address information assigned by the operator, and its mapping relationship with the payload satellite is also pre-assigned, thus revealing the identifier of the payload satellite where the UPF and / or FW resides. Ephemeris information can be maintained by the satellite network operator and distributed to the ground operator, who then configures it for the ground control center. The feeder connection status between the satellite identifier and the ground station, and the connected objects (e.g., whether the feeder is valid and which ground station it is connected to when a domain name resolution request is received) can be obtained from the ephemeris information.

[0169] S608: The second network element determines the application server corresponding to the application requested by the terminal device based on the location of the ground gateway corresponding to the UPF and / or FW.

[0170] After the ground dispatch center determines the location of the ground gateway corresponding to the UPF and / or FW, it can select an application server for the terminal device based on the location of the ground gateway corresponding to the UPF and / or FW. For example, it can select the application server that is closest to the terminal device, or the application server that is close to the terminal device and has the best service quality.

[0171] In other words, the ground dispatch center can be configured with ephemeris information, and can learn from the ephemeris information the satellite identifier where the UPF and / or FW are located, the ground gateway address that the satellite is currently connected to, and find the IP address of the application server closest to the ground gateway based on the geographical location information of the ground gateway.

[0172] Based on S608, the ground dispatch center can obtain the mapping relationship between the UPF and / or FW and the geographical location of the ground gateway. This geographical location information can be used to address the application server for the terminal device, thereby reducing the latency of terminal device application access in NTN communication scenarios.

[0173] S609: The second network element sends the domain name resolution result to the terminal device, which includes the IP address corresponding to the domain name. Correspondingly, the terminal device receives the domain name resolution result from the second network element.

[0174] It should be noted that, for S606-S609, the second network element can be an LDNS-T server and a ground dispatch center. In one possible implementation, the LDNS-T server and the ground dispatch center can be deployed separately or jointly. The aforementioned embodiments are described according to the implementation of separate deployment. If deployed jointly, the process can be further simplified, that is, the interaction between the LDNS-T server and the ground dispatch center can be implemented internally by the second network element.

[0175] pass Figure 6 The illustrated embodiment provides an optimized solution for application access by terminal devices in an NTN communication scenario. Unlike traditional methods where the first network element prioritizes querying the locally cached application server's IP address, potentially resolving the IP address of the satellite-deployed application server to the IP address of the previous ground-based application server, thus increasing latency for terminal device application access, this embodiment allows the first network element to select an application server based on the application's deployment distribution (e.g., whether it's deployed on a satellite) using the application tag indication in the received first domain name resolution request. If the application requested by the terminal device is deployed on a satellite, the satellite-based application server can be prioritized for service, thereby reducing latency for terminal device application access in an NTN communication scenario.

[0176] It is understood that, in order to achieve the functions in the above embodiments, the first network element, the UPF, and the second network element include hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0177] Figure 8 and Figure 9 This is a schematic diagram of the possible communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of the first network element, UPF, or second network element in the above method embodiments, and therefore can also achieve the beneficial effects of the above method embodiments. The communication device can be the first network element, UPF, or second network element, or it can be a device (e.g., a chip, a chip system, or a circuit) within the first network element, UPF, or second network element. Figure 8 As shown, the communication device 800 includes at least a transceiver unit 801 and a processing unit 802. The communication device 800 is used to implement the above-described... Figure 6 The method embodiment shown illustrates the functions of the first network element, UPF, or second network element.

[0178] When the communication device 800 is used to implement Figure 6 In the method embodiment shown, the function of the first network element is as follows:

[0179] The transceiver unit 801 is used to receive a first domain name resolution request from a terminal device. The first domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The IP address is used by the terminal device to request access to the application corresponding to the IP address. The first domain name resolution request carries the domain name requested by the terminal device and an application tag indicator. The application tag indicator is used to indicate the deployment status of the application requested by the terminal device. The deployment status includes whether the application is deployed on the satellite.

[0180] The processing unit 802 is used to query the IP address corresponding to the domain name based on the application tag indication and the domain name.

[0181] Optionally, the processing unit 802 queries the IP address corresponding to the domain name based on the application tag indication and the domain name, specifically for: querying whether the domain name and the application tag indication match the local cache record;

[0182] In the case of a match, the transceiver unit 801 is further configured to send the domain name resolution result corresponding to the domain name to the terminal device, the domain name resolution result including the IP address corresponding to the domain name; or,

[0183] In the event of a mismatch, the transceiver unit 801 is also used to send a third domain name resolution request to the second network element, wherein the second network element is deployed on the ground, and the third domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The IP address is used by the terminal device to request access to the application corresponding to the IP address. The third domain name resolution request carries the domain name requested by the terminal device and the application tag indication carried in the first domain name resolution request.

[0184] Optionally, in the event of a mismatch, before the transceiver unit 801 forwards the first domain name resolution request to the second network element, the processing unit 802 is also used to query whether the satellite where the first network element is located has a valid feeder connection to the ground;

[0185] If so, transceiver unit 801 is also used to send a third domain name resolution request to the second network element; or,

[0186] If not, transceiver unit 801 is also used to send DNS resolution responses to terminal devices.

[0187] Optionally, the DNS resolution response may include the reason for the DNS resolution failure and / or suggested information.

[0188] Optionally, the transceiver unit 801 receives a first domain name resolution request from the terminal device, specifically for: receiving a first domain name resolution request from the terminal device via UPF.

[0189] Optionally, in the first domain name resolution request, the application tag indicates that it is located after the domain name that the terminal device is requesting to resolve.

[0190] When the communication device 800 is used to implement Figure 6 The function of UPF in the method embodiment shown is as follows:

[0191] The transceiver unit 801 is used to receive a second domain name resolution request from a terminal device. The second domain name resolution request carries the domain name that the terminal device requests to resolve. The second domain name resolution request is used to request the resolution of the IP address corresponding to the domain name that the terminal device requests to resolve. The IP address is used by the terminal device to request access to the application corresponding to the IP address.

[0192] The processing unit 802 is configured to determine an application tag indication based on the second domain name resolution request. The application tag indication is used to indicate the deployment status of the application requested by the terminal device, including whether the application is deployed on a satellite.

[0193] Optionally, the processing unit 802 determines the application tag indication based on the second domain name resolution request, specifically for: obtaining application subscription data and / or user plane forwarding rule information; determining the application tag indication based on the application subscription data and / or user plane forwarding rule information; the application tag indication is used to indicate the deployment status of the application requested by the terminal device, the deployment status including whether the application is deployed on the satellite.

[0194] Optionally, the transceiver unit 801 is further configured to send a first domain name resolution request to the first network element. The first domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The first domain name resolution request carries the domain name requested by the terminal device and the application tag indication. The first network element is deployed on a satellite.

[0195] Optionally, in the first domain name resolution request, the application tag indicates that it is located after the domain name that the terminal device is requesting to resolve.

[0196] When the communication device 800 is used to implement Figure 6 The function of UPF in the method embodiment shown is as follows:

[0197] The transceiver unit 801 is used to receive a third domain name resolution request. The third domain name resolution request carries the domain name requested by the terminal device for resolution, the application tag indicator, and the identifiers of UPF and / or FW. The UPF and / or FW are the UPF and / or FW of the second domain name resolution request received by the terminal device. The third domain name resolution request is used to request the resolution of the IP address corresponding to the domain name requested by the terminal device. The IP address is used by the terminal device to request access to the application corresponding to the IP address. The application tag indicator is used to indicate the deployment status of the application requested by the terminal device. The deployment status includes whether the application is deployed on the satellite.

[0198] Processing unit 802 is used to determine the ground gateway location corresponding to the UPF and / or FW based on the mapping relationship between the UPF and / or FW and the ground gateway location and the identifier of the UPF and / or FW.

[0199] Processing unit 802 is also used to determine the application server corresponding to the application requested by the terminal device based on the location of the ground gateway corresponding to the UPF and / or FW.

[0200] Optionally, the processing unit 802 is also used to obtain the mapping relationship between the UPF and / or FW and the location of the ground gateway.

[0201] Optionally, the transceiver unit 801 is also used to send the domain name resolution result corresponding to the domain name to the terminal device, the domain name resolution result including the IP address corresponding to the domain name.

[0202] For a more detailed description of the transceiver unit 801 and the processing unit 802 mentioned above, please refer to [link / reference]. Figure 6 The relevant descriptions in the method embodiments shown.

[0203] Please see Figure 9 , Figure 9 This is a schematic diagram of another communication device provided in an embodiment of this application. The device 110 is used to implement the functions of the network element of this application; for example, the network element can be a first network element, a UPF, or a second network element. The device 110 can be the network element, or a device that can be installed in the network element, or a device that can be used in conjunction with the network element; there are no limitations. For example, the device can be a chip or a chip system. Figure 9As shown, the device 110 includes an interface 111 and a processor 112. Optionally, the processor 112 is used to execute a program 114. The processor 112 may store the program 114 or obtain the program 114 from other devices or equipment (e.g., from memory 113 or downloaded from a third-party website). Optionally, the device 110 includes a memory 113. The memory 113 is used to store a program 115. The program 115 may be pre-stored or loaded later. Optionally, the memory 113 may also be used to store necessary data. These components work together to provide the various functions described in this application.

[0204] Processor 112 may include one or more processors as a combination of computing devices. Processor 112 may include one or more of the following: microprocessor, microcontroller, digital signal processor (DSP), digital signal processing device (DSPD), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), programmable logic device (PLD), gated logic, transistor logic, discrete hardware circuitry, processing circuitry, or other suitable hardware, firmware, and / or combinations of hardware and software configured to perform the various functions described in this application. Processor 112 may be a general-purpose processor or a special-purpose processor. For example, processor 112 may be a baseband processor or a central processing unit (CPU). A baseband processor may be used to process communication protocols and communication data. A CPU may be used to execute software programs and process data within those software programs.

[0205] Interface 111 may include any suitable hardware or software for enabling communication with one or more computer devices (such as the network elements of this application). For example, in some embodiments, interface 111 may include wires for coupling wired connections or terminals and / or pins for coupling wireless connections with wireless transceivers. In some embodiments, interface 111 may include a transmitter, receiver, transceiver, and / or antenna. The interface may be configured to enable communication between computer devices (such as the network elements of this application) using any available protocol (such as 3GPP standard protocols).

[0206] In this application, "program" refers to software in a broad sense. The software can be program code, a program, a subroutine, an instruction set, code, a code segment, a software module, an application program, a software application, etc. The program can run on a processor and / or computer to perform the various functions and / or processes described in this application.

[0207] Memory 113 may store necessary data required by processor 112 when executing software. Memory 113 may be implemented using any suitable storage technology. For example, memory 113 may be any available storage medium accessible to the processor and / or computer. Non-limiting examples of storage media include: random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), removable media, optical disc storage, magnetic disk storage media, magnetic storage devices, flash memory, registers, state memory, remote mounting memory, local or remote memory components, or any other medium that can carry or store software, data, or information and is accessible to the processor / computer.

[0208] The memory 113 and processor 112 can be configured separately or integrated together. The processor 112 can read information from, store, and / or write information to the memory 113. The memory 113 can be integrated into the processor 112. The processor 112 and memory 113 can be housed in an integrated circuit (e.g., an application-specific integrated circuit, ASIC). This integrated circuit can be located in the network element of this disclosure or in other network nodes.

[0209] Optionally, the apparatus 110 in the embodiments of this application can be used to perform the methods described in the embodiments of this application.

[0210] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, can implement the processes related to the first network element, UPF, and second network element in the communication method provided in the above method embodiments.

[0211] This application also provides a computer program product that, when run on a computer or processor, causes the computer or processor to execute one or more steps of any of the above-described communication methods. If the constituent modules of the aforementioned devices are implemented as software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0212] This application also provides a chip system including at least one processor and a communication interface. The communication interface and the at least one processor are interconnected via a circuit. The at least one processor is used to run computer programs or instructions to perform some or all of the steps described in any of the corresponding method embodiments above. This chip system may be composed of chips or may include chips and other discrete devices.

[0213] This application also provides a communication system, which includes a first network element, a UPF, and a second network element. For a detailed description, please refer to the method shown above.

[0214] It should be understood that the memory mentioned in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be a hard disk drive (HDD), a solid-state drive (SSD), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DRRAM). Memory is any other medium capable of carrying or storing desired program code having an instruction or data structure form and accessible by a computer, but is not limited thereto. The memory in the embodiments of this application may also be circuitry or any other means capable of implementing storage functions for storing program instructions and / or data.

[0215] It should also be understood that the processor mentioned in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0216] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) is integrated into the processor.

[0217] It should be noted that the memories described herein are intended to include, but are not limited to, these and any other suitable types of memories.

[0218] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0219] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments provided herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0220] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0221] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0222] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0223] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0224] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the technology, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0225] The steps in the method of this application embodiment can be adjusted, combined, or deleted according to actual needs.

[0226] The modules / units in the device of this application embodiment can be merged, divided, and deleted according to actual needs.

[0227] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A communication method characterized by comprising: The method is applied to a first network element, and the first network element is deployed on a satellite, and the method comprises the following steps: Receiving a first domain name resolution request from a terminal device, the first domain name resolution request being used to request resolution of an IP address corresponding to a domain name requested to be resolved by the terminal device, the IP address being used for the terminal device to request access to an application corresponding to the IP address, the first domain name resolution request carrying the domain name requested to be resolved by the terminal device and an application label indication, the application label indication being used to indicate a deployment state of the application requested to be accessed by the terminal device, the deployment state comprising whether the application is deployed on a satellite; Querying the IP address corresponding to the domain name according to the application label indication and the domain name.

2. The method of claim 1, wherein, The step of querying the IP address corresponding to the domain name according to the application label indication and the domain name comprises the following steps: Querying whether the domain name and the application label indication match a local cache record; In the case of a match, sending a domain name resolution result corresponding to the domain name to the terminal device, the domain name resolution result comprising the IP address corresponding to the domain name; or, In the case of a mismatch, sending a third domain name resolution request to a second network element, wherein the second network element is deployed on the ground, the third domain name resolution request being used to request resolution of an IP address corresponding to a domain name requested to be resolved by the terminal device, the IP address being used for the terminal device to request access to an application corresponding to the IP address, the third domain name resolution request carrying the domain name requested to be resolved by the terminal device and the application label indication carried in the first domain name resolution request.

3. The method of claim 2, wherein, Before the step of sending the third domain name resolution request to the second network element in the case of a mismatch, the method further comprises the following steps: Querying whether there is a valid feeder link connecting the ground for a satellite where the first network element is located; If there is, sending the third domain name resolution request to the second network element; or, If there is not, sending a DNS resolution response to the terminal device.

4. The method of claim 3, wherein, The DNS resolution response comprises DNS resolution failure reasons and / or suggestion information.

5. The method according to any one of claims 1 to 4, characterized in that, The step of receiving the first domain name resolution request from the terminal device comprises the following step: Receiving the first domain name resolution request from the terminal device through a user plane function UPF.

6. The method according to any one of claims 1 to 5, characterized in that, In the first domain name resolution request, the application label indication is located after the domain name requested to be resolved by the terminal device.

7. A communication method characterized by comprising: The method is applied to a user plane function UPF, and the method comprises the following steps: Receiving a second domain name resolution request from a terminal device, the second domain name resolution request carrying a domain name requested to be resolved by the terminal device, the second domain name resolution request being used to request resolution of an IP address corresponding to the domain name requested to be resolved by the terminal device, the IP address being used for the terminal device to request access to an application corresponding to the IP address; Determining an application label indication according to the second domain name resolution request, the application label indication being used to indicate a deployment state of the application requested to be accessed by the terminal device, the deployment state comprising whether the application is deployed on a satellite.

8. The method of claim 7, wherein, The step of determining the application label indication according to the second domain name resolution request comprises the following steps: Obtaining application subscription data and / or user plane forwarding rule information; Determining the application label indication according to the application subscription data and / or the user plane forwarding rule information.

9. The method of claim 8, wherein, The method further includes: sending a first domain name resolution request to a first network element, the first domain name resolution request being used to request resolution of a network protocol IP address corresponding to a domain name requested by the terminal device for resolution, the first domain name resolution request carrying the domain name requested by the terminal device for resolution and the application label indication, the first network element being deployed on a satellite.

10. The method of claim 9, wherein, In the first domain name resolution request, the application label indication is located after the domain name requested by the terminal device for resolution.

11. A communication method characterized by comprising: The method applied to a second network element deployed on the ground includes: receiving a third domain name resolution request, the third domain name resolution request carrying a domain name requested by a terminal device for resolution, an application label indication, an identifier of a user plane function UPF and / or a firewall FW, the UPF and / or the FW being a UPF and / or a FW receiving a second domain name resolution request of the terminal device; wherein the third domain name resolution request is used to request resolution of a network protocol IP address corresponding to the domain name requested by the terminal device for resolution, the IP address being used for the terminal device to request access to an application corresponding to the IP address, the application label indication being used to indicate a deployment state of the application requested to be accessed by the terminal device, the deployment state including whether the application is deployed on a satellite; determining a ground gateway location corresponding to the UPF and / or the FW according to a mapping relationship between the UPF and / or the FW and ground gateway locations and the identifier of the UPF and / or the FW; determining an application server corresponding to the application requested to be accessed by the terminal device according to the ground gateway location corresponding to the UPF and / or the FW.

12. The method of claim 11, wherein, The method further includes: obtaining a mapping relationship between the UPF and / or the FW and ground gateway locations.

13. The method according to claim 11 or 12, characterized in that, The method further includes: sending a domain name resolution result corresponding to the domain name to the terminal device, the domain name resolution result including an IP address corresponding to the domain name.

14. A communications device, characterized by The communication device includes a processor and a storage medium, the storage medium storing instructions, the instructions being run by the processor to cause the method as claimed in any one of claims 1-6 or as claimed in any one of claims 7-10 or claims 11-13 to be implemented.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes instructions, the instructions being run by a processor to cause the method as claimed in any one of claims 1-6 or as claimed in any one of claims 7-10 or claims 11-13 to be implemented.

16. A communication system, characterized by The first network element is used to implement the method as claimed in any one of claims 1-6, the UPF is used to implement the method as claimed in any one of claims 7-10, and the second network element is used to implement the method as claimed in any one of claims 11-13.

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