Communication method, apparatus and system

Abstract

Embodiments of the present application provide a communication method, apparatus and system. The method comprises: a first network element receiving a first domain name resolution request from a terminal device, wherein the first domain name resolution request is used for requesting to resolve an IP address corresponding to a domain name that the terminal device requests to resolve, the IP address is used by the terminal device to request to access an application corresponding to the IP address, the first domain name resolution request carries the domain name that the terminal device requests to resolve and an application tag indication, the application tag indication is used for indicating a deployment status of the application that the terminal device requests to access, and the deployment status comprises whether the application is deployed on a satellite; and on the basis of the application tag indication, querying the IP address corresponding to the domain name. By means of the technical solution provided in the present application, the delay of application access of a terminal device in an NTN communication scenario can be reduced.

Description

A communication method, apparatus and system

[0001] The present application claims priority from the Chinese patent application No. 202411098799.2 filed on August 9, 2024, and entitled "A communication method, apparatus and system", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of wireless communication, and in particular to a communication method, apparatus and system. BACKGROUND

[0003] The domain name system (DNS) is a distributed database for implementing the mapping between domain names and internet protocol (IP) addresses. The process of obtaining the IP address corresponding to a host name (i.e., a fully qualified domain name) through the host name is called domain name resolution (or host name resolution).

[0004] Before a terminal device initiates a hypertext transfer protocol (HTTP) request / application access to an application server (AS), the network can first convert the domain name / uniform resource locator (URL) / host name of the application server into an IP address, which can be referred to as DNS resolution. Specifically, the terminal device sends a DNS resolution request to a DNS server, and the DNS server sends the resolved IP address to the terminal device, so that the terminal device can initiate a transmission control protocol (TCP) connection to the application server corresponding to the IP address.

[0005] However, for non-terrestrial networks (NTN), such as satellite communication, the application server can be deployed on a satellite, or can be deployed on the ground, or can be deployed on a satellite and the ground on demand according to an application strategy. How a terminal device performs application access in an NTN communication scenario is a problem to be solved. SUMMARY

[0006] Embodiments of the present application provide a communication method, apparatus and system to provide an optimized solution for a terminal device to perform application access in an NTN communication scenario.

[0007] In a first aspect, an embodiment of the present application provides a communication method, which can be applied to a first network element (for example, a non-terrestrial local DNS (DNS-non terrestrial, LDNS-NT)), can also be applied to a device (for example, a chip, or a chip system, or a circuit) in the first network element, or a device that can be matched with the first network element, and is described below by taking the application to the first network element as an example. The method provides an optimized solution for application access of a terminal device in an NTN communication scenario. The first network element can be deployed on a satellite, and the method can include: receiving, by the first network element, 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 by the terminal device to be resolved, the IP address being used for the terminal device to request access to an application corresponding to the IP address; wherein the first domain name resolution request carries the domain name requested by the terminal device to be resolved and an application label indication, the application label indication being used to indicate a deployment state of the application requested by the terminal device to be accessed, the deployment state including whether the application is deployed on a satellite; and querying the IP address corresponding to the domain name according to the application label indication and the domain name.

[0008] For the case where the application server is deployed on a satellite, it is found through research that, because the DNS server preferentially queries the locally cached IP of the application server, the IP of the application server deployed on the satellite can be resolved into the IP of the last ground application server, thereby increasing the time delay of application access of the terminal device. Therefore, how to reduce the time delay of application access of the terminal device in the NTN communication scenario is a problem to be solved.

[0009] Unlike the first network element preferentially querying the locally cached IP of the application server, which can resolve the IP of the application server deployed on the satellite into the IP of the last ground application server, thereby increasing the time delay of application access of the terminal device. In the embodiment of the present application, the first network element can select the application server according to the deployment distribution of the application (for example, whether the application is deployed on a satellite) through the application label indication in the received first domain name resolution request. For example, if the application requested by the terminal device to be accessed is deployed on a satellite, the application server on the satellite can be preferentially selected to serve the terminal device, thereby reducing the time delay of application access of the terminal device in the NTN communication scenario.

[0010] In a possible implementation, the querying the IP address corresponding to the domain name according to the application label indication and the domain name comprises: querying whether the domain name and the application label indication match a local cache record; in the case of a match, sending, to the terminal device, a domain name resolution result corresponding to the domain name, the domain name resolution result comprising the IP address corresponding to the domain name; or in the case of a mismatch, sending, to a second network element deployed on the ground, a third domain name resolution request for requesting to resolve the IP address corresponding to the domain name requested by the terminal device to access the application corresponding to the IP address, the third domain name resolution request carrying the domain name requested by the terminal device to resolve and the application label indication carried in the first domain name resolution request. According to the embodiment of the application, the first network element can match the IP address corresponding to the domain name requested by the terminal device according to the application label indication and the domain name and the local cache record, for example, the first network element can preferentially query the local DNS cache record to check whether the IP address corresponding to the domain name requested by the terminal device to resolve (namely, the IP address corresponding to the application requested by the terminal device to access) exists in the local DNS cache record, if the IP address exists (namely, if the match exists), the first network element can send the IP address to the terminal device, if the IP address does not exist (namely, if the mismatch exists), it indicates that the application server of the application is not deployed on the satellite, and at this time, the first network element can forward the first domain name resolution request to the second network element deployed on the ground (namely, 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 by the terminal device to resolve. The distribution of the deployment of the application can be used to select the corresponding application server for the terminal device, and the time delay of the terminal device to access the application in the NTN communication scenario can be reduced.

[0011] In a possible implementation, before the third domain name resolution request is sent to the second network element in the case of a mismatch, the communication method can further comprise: querying whether there is a valid feeder link connecting the ground for the 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. According to the embodiment of the application, before the first network element forwards 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 link connecting the ground, and in the case of the existence of the valid feeder link, the forwarding of the domain name resolution request is performed, and in the case of the nonexistence of the valid feeder link, the terminal device can be timely notified of the DNS resolution response, so that the signaling overhead can be saved.

[0012] In a possible implementation, the DNS resolution response comprises a DNS resolution failure cause and / or suggestion information. Through the embodiments of the present application, in the case where there is no valid feeder link, the first network element can timely notify the terminal device to switch the object of the domain name resolution request (for example, suggest the terminal device to change the DNS resolution server address or change to the ground network for DNS resolution), so as to reduce the access delay of the terminal device application.

[0013] In a possible implementation, the receiving the first domain name resolution request from the terminal device comprises: receiving the first domain name resolution request from the terminal device by a user plane function (UPF). The UPF can be understood as a kind of network element, and in some embodiments of the present application, the UPF is deployed in a satellite.

[0014] In a possible implementation, in the first domain name resolution request, the application label indication is located after the domain name requested by the terminal device for resolution.

[0015] In a second aspect, the embodiments of the present application provide a communication method, which can be applied to a UPF, a device (for example, a chip, or a chip system, or a circuit) in the UPF, or a device capable of being used with the UPF. Hereinafter, the method applied to the UPF is taken as an example for description. The method can comprise: receiving, by the UPF, a second domain name resolution request from a terminal device, the second domain name resolution request carrying a domain name requested by the terminal device for resolution, the second domain name resolution request being used to request resolution of an 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; and determining, by the UPF, 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 by the terminal device to access, the deployment state comprising whether the application is deployed on a satellite.

[0016] In the embodiments of the present application, the UPF can determine the application label indication and carry the application label indication in a domain name resolution request sent to the first network element, so that the first network element can select an application server according to the deployment distribution of the application (for example, whether the application is deployed on a satellite). If the application requested by the terminal device to access is deployed on a satellite, the application server on the satellite can be preferentially selected to serve the terminal device, so that the access delay of the terminal device application in the NTN communication scenario can be reduced.

[0017] It should be understood that the execution subject of the second aspect can be the UPF, the specific content of the second aspect corresponds to the content of the first aspect, and the corresponding features and beneficial effects of the second aspect can be referred to the description of the first aspect. To avoid repetition, the detailed description is appropriately omitted here.

[0018] In a possible implementation, the determining the application label indication according to the second domain name resolution request comprises: 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; and the application label indication is used to indicate a deployment state of an application requested to be accessed by the terminal device, and the deployment state comprises whether the application is deployed on the satellite.

[0019] In a possible implementation, the communication method further comprises: sending a first domain name resolution request to a first network element, the first domain name resolution request being used to request to resolve an IP address corresponding to a domain name requested to be resolved by the terminal device, and the first domain name resolution request carrying the domain name requested to be resolved by the terminal device and the application label indication, and the first network element being deployed on the satellite.

[0020] In a possible implementation, 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.

[0021] In a third aspect, an embodiment of the present application provides a communication method, which can be applied to a second network element (for example, a local DNS-terrestrial, LDNS-T, and / or a ground scheduling center) and / or a device (for example, a chip, or a chip system, or a circuit) in the second network element, or a device capable of being matched with the second network element, and is described below by taking the application to the second network element as an example. The method can comprise: receiving, by the second network element, a third domain name resolution request, the third domain name resolution request carrying a domain name requested to be resolved by a terminal device, an application label indication, an identifier of a UPF and / or a firewall (FW), and the UPF and / or the FW being a UPF and / or a FW receiving a second domain name resolution request of the terminal device; the third domain name resolution request being used to request to resolve 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 to access an application corresponding to the IP address, and the application label indication being used to indicate a deployment state of the application requested to be accessed by the terminal device, and the deployment state comprising whether the application is deployed on the 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 the ground gateway location and the identifier of the UPF and / or the FW; and 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.

[0022] The second network element can determine the ground gateway location corresponding to the UPF and / or the FW based on the identifier of the UPF and / or the FW carried in the domain name resolution request and the mapping relationship between the UPF and / or the FW and the ground gateway location, can schedule and match to find the IP address of the application server closest to the ground gateway based on the geographic location information of the ground gateway, and thus determine the application server providing services for the terminal device, thereby reducing the latency of application access by the terminal device in the NTN communication scenario.

[0023] It should be understood that the execution subject 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 and beneficial effects of the third aspect can be referred to the description of the first aspect. To avoid repetition, the detailed description is appropriately omitted here.

[0024] In a possible implementation, the communication method can further include: obtaining the mapping relationship between the UPF and / or the FW and the ground gateway location.

[0025] In a possible implementation, the communication method can further include: sending 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.

[0026] In a fourth aspect, an embodiment of the present application provides a communication device, which can be the first network element or a device (for example, a chip, a chip system, or a circuit) in the first network element.

[0027] The beneficial effects can be referred to the description of the first aspect, which will not be repeated here. The device has the function of implementing the behaviors in the method examples of the above-mentioned first aspect. The 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-mentioned functions.

[0028] In a possible implementation, the communication device can include:

[0029] The transceiver is configured to receive 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 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; wherein the first domain name resolution request carries the domain name requested by the terminal device for resolution and an application label indication, the application label indication being used to indicate the deployment state of the application requested by the terminal device to access, the deployment state including whether the application is deployed on a satellite;

[0030] The processing unit is configured to query the IP address corresponding to the domain name according to the application label indication and the domain name.

[0031] In a possible implementation, the processing unit queries an IP address corresponding to the domain name according to the application label indication and the domain name, and specifically used for: querying whether the domain name and the application label indication match a local cache record.

[0032] In the case of matching, the transceiving unit is further configured to send, to the terminal device, a domain name resolution result corresponding to the domain name, the domain name resolution result including the IP address corresponding to the domain name; or,

[0033] In the case of not matching, the transceiving unit is further configured to send, to a second network element deployed on the ground, a third domain name resolution request, the third domain name resolution request being used to request resolution of an IP address corresponding to a domain name requested by the terminal device to be resolved, the IP address being used for the terminal device to request access to an application corresponding to the IP address, and the third domain name resolution request carrying the domain name requested by the terminal device to be resolved and the application label indication carried in the first domain name resolution request.

[0034] In a possible implementation, in the case of not matching, before the transceiving unit sends, to the second network element, the third domain name resolution request, the processing unit is further configured to query whether there is a valid feeder link connecting the ground for a satellite where the first network element is located.

[0035] If yes, the transceiving unit is further configured to send, to the second network element, the third domain name resolution request; or,

[0036] If no, the transceiving unit is further configured to send, to the terminal device, a DNS resolution response.

[0037] In a possible implementation, the DNS resolution response includes a DNS resolution failure reason and / or suggestion information.

[0038] In a possible implementation, the transceiving unit receives the first domain name resolution request from the terminal device, and specifically used for: receiving, by the UPF, the first domain name resolution request from the terminal device.

[0039] In a possible implementation, in the first domain name resolution request, the application label indication is located after the domain name requested by the terminal device to be resolved.

[0040] In a fifth aspect, an embodiment of the present application provides a communication apparatus, which can be a UPF or a device (for example, a chip, a chip system, or a circuit) in the UPF.

[0041] The beneficial effects can be referred to the description of the second aspect, which will not be repeated here. The apparatus has the functions of implementing the behaviors in the method examples of the second aspect. The functions can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions.

[0042] In a possible implementation, the communication apparatus can include:

[0043] The transceiver is configured to receive a second domain name resolution request from the terminal device, the second domain name resolution request carrying a domain name requested to be resolved by the terminal device, and 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.

[0044] The processing unit is configured to determine 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 including whether the application is deployed on a satellite.

[0045] In a possible implementation, the processing unit determines the application label indication according to the second domain name resolution request, specifically, obtains application subscription data and / or user plane forwarding rule information, and determines the application label indication according to the application subscription data and / or the user plane forwarding rule information, the application label indication being used to indicate the 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.

[0046] In a possible implementation, the transceiver is further configured to send a first domain name resolution request to a first network element, the first 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 first domain name resolution request carrying the domain name requested to be resolved by the terminal device and the application label indication, and the first network element being deployed on a satellite.

[0047] In a possible implementation, 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.

[0048] In a sixth aspect, an embodiment of the present application provides a communication apparatus, which can be a second network element or a device (for example, a chip, a chip system, or a circuit) in the second network element.

[0049] The beneficial effects can refer to the description of the third aspect, which will not be repeated here. The apparatus has the function of implementing the behaviors in the method examples of the third aspect. The 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 functions.

[0050] In a possible implementation, the communication apparatus can include:

[0051] The transceiver is configured to receive 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, and an identifier of a UPF and / or a FW, the UPF and / or the FW being a UPF and / or a FW that receives a second domain name resolution request of the terminal device, wherein the third domain name resolution request is used to request resolution of an 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, and the application label indication is used to indicate a deployment state of the application requested by the terminal device to access, the deployment state including whether the application is deployed on a satellite.

[0052] The processing unit is configured to determine a ground gateway position corresponding to the UPF and / or the FW according to a mapping relationship between the UPF and / or the FW and the ground gateway position and the identifier of the UPF and / or the FW.

[0053] The processing unit is further configured to determine an application server corresponding to the application requested by the terminal device to access according to the ground gateway position corresponding to the UPF and / or the FW.

[0054] In a possible implementation, the processing unit is further configured to obtain the mapping relationship between the UPF and / or the FW and the ground gateway position.

[0055] In a possible implementation, the transceiver is further configured to send, to the terminal device, a domain name resolution result corresponding to the domain name, the domain name resolution result including an IP address corresponding to the domain name.

[0056] In a seventh aspect, a communication apparatus is provided. The apparatus can be a first network element or a device (e.g., a chip, a chip system, or a circuit) in the first network element. The apparatus can include a processor, a memory, an input interface, and an output interface. The input interface is configured to receive information from other communication apparatuses outside the apparatus. The output interface is configured to output information to other communication apparatuses outside the apparatus. The processor is configured to invoke a computer program stored in the memory to execute the communication method in the first aspect or any of the implementation forms of the first aspect.

[0057] In an eighth aspect, a communication apparatus is provided. The apparatus can be a UPF or a device (e.g., a chip, a chip system, or a circuit) in the UPF. The apparatus can include a processor, a memory, an input interface, and an output interface. The input interface is configured to receive information from other communication apparatuses outside the apparatus. The output interface is configured to output information to other communication apparatuses outside the apparatus. The processor is configured to invoke a computer program stored in the memory to execute the communication method in the second aspect or any of the implementation forms of the second aspect.

[0058] In a ninth aspect, a communication apparatus is provided, which can be a second network element or a device (e.g., a chip or a chip system or a circuit) in the second network element. The apparatus can include a processor, a memory, an input interface and an output interface, the input interface being configured to receive information from other communication apparatuses outside the apparatus, the output interface being configured to output information to other communication apparatuses outside the apparatus, and the processor being configured to invoke a computer program stored in the memory to perform the communication method provided in the third aspect or any of the implementation manners of the third aspect.

[0059] In a tenth aspect, a communication system is provided, which includes at least one first network element, at least one UPF and at least one second network element, and is configured to perform any of the communication methods provided in the first aspect, the second aspect or the third aspect when the at least one first network element, the at least one UPF and the at least one second network element are running in the system.

[0060] In an eleventh aspect, a computer readable storage medium is provided, which stores computer instructions, and when the computer program or the computer instructions are executed, the method provided in the first aspect or any of the possible implementation manners thereof, the second aspect or any of the possible implementation manners thereof, or the third aspect or any of the possible implementation manners thereof is performed.

[0061] In a twelfth aspect, a computer program product is provided, which includes executable instructions, and when the computer program product is executed on a communication device, the method provided in the first aspect or any of the possible implementation manners thereof, the second aspect or any of the possible implementation manners thereof, or the third aspect or any of the possible implementation manners thereof is performed.

[0062] In a thirteenth aspect, a communication apparatus is provided, which includes a processor and can further include a memory, and is configured to implement the method provided in the first aspect or any of the possible implementation manners thereof, the second aspect or any of the possible implementation manners thereof, or the third aspect or any of the possible implementation manners thereof. The apparatus can be a chip system, which can be composed of a chip or can include a chip and other discrete devices. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows.

[0064] FIG. 1 is a schematic diagram of a non-terrestrial communication system provided by an embodiment of the present application;

[0065] FIG. 2 is a schematic diagram of a 5G satellite communication system architecture provided by an embodiment of the present application;

[0066] Fig. 3 is a schematic diagram of an architecture of a satellite DNS according to an embodiment of the present application;

[0067] Fig. 4 is a schematic diagram of a structure of an LDNS server according to an embodiment of the present application;

[0068] Fig. 5 is a schematic diagram of an architecture of a satellite DNS according to an embodiment of the present application;

[0069] Fig. 6 is a schematic diagram of an interaction of a communication method according to an embodiment of the present application;

[0070] Fig. 7 is a schematic diagram of an iterative query according to an embodiment of the present application;

[0071] Fig. 8 and Fig. 9 are schematic diagrams of structures of possible communication apparatuses according to embodiments of the present application. DETAILED DESCRIPTION

[0072] The specific embodiments of the present application will be further described with reference to the drawings.

[0073] The terms "first" and "second" and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a specific sequential or chronological order. Descriptions of a process, step, or block of the appending claims or the specification in a form of "comprising", "including", "containing" or "having" are meant not to be limiting. Accordingly, the process, step, or block can include more, less, or different elements than those expressly listed.

[0074] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all directed to the same embodiment, or to a common alternative embodiment. It is expressly understood that any of the features, structures, or characteristics described in connection with an embodiment can be included in at least one implementation of the application.

[0075] In the present application, "at least one" means one or more, "multiple" means two or more, "at least two" means two or three and three or more, and "and / or" is used to describe the relationship between the associated objects, which means that there can be three relationships, for example, "A and / or B" can mean: only A, only B, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one 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.

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

[0077] In the present application, "receiving information" can be understood as one device receiving information from another device, or also can be understood as one logical module in a device receiving information from another logical module. For example, "the access network device receiving information" can be understood as the access network device receiving information from another device (such as a terminal), or can be understood as a logical module 1 in the access network device receiving information from a logical module 2 in the access network device.

[0078] In the present application, "sending information to (for example, a terminal)" can be understood as the destination of the information being the terminal. It can include directly or indirectly sending information to the terminal. "Receiving information from (for example, a terminal)" or "receiving information from (for example, a terminal)" can be understood as the source of the information being the terminal, which can include directly or indirectly receiving information from the terminal. The information between the source and the destination of the information sending can be processed as necessary, such as format change, etc., but the destination can understand the valid information from the source. Similar expressions in the present application can be understood similarly, and will not be repeated here.

[0079] In order to better understand the embodiments of the present application, first, the system architecture related to the embodiments of the present application is introduced as follows:

[0080] The embodiments of the present application can be applied to a communication system such as a satellite communication system, including a satellite base station, a ground station, and a terminal device type network element. The satellite base station provides communication services for the terminal device, and the satellite base station transmits downlink data to the terminal device, wherein the data is encoded by channel coding, and the data after channel coding is transmitted to the terminal device after constellation modulation; the terminal device transmits uplink data to the satellite base station, and the uplink data can also be encoded by channel coding, and the encoded data is transmitted to the satellite base station after constellation modulation. The wireless communication system can include one or more network devices and one or more terminal devices.

[0081] The communication method provided by the embodiments of the present application can be applied to an NTN communication system, which is exemplarily explained below with reference to the system architecture shown in FIG. 1. As shown in FIG. 1, the NTN communication system includes a network device 101 and a terminal device 102.

[0082] The terminal device 102 can also be referred to as a user equipment (UE), a mobile station (MS), a mobile terminal (MT), etc., or a device for providing voice or data connectivity to a user, which can also be an Internet of Things (IoT) device. For example, the terminal device includes a handheld device with wireless connection function, a vehicle-mounted device, etc. At present, the terminal device can be a mobile phone, a tablet computer, a notebook computer, a palm computer, a mobile internet device (MID), a wearable device (such as a smart watch, a smart bracelet, a pedometer, etc.), a vehicle-mounted device (such as a car, a bicycle, an electric vehicle, an airplane, a ship, a train, a high-speed rail, etc.), a satellite terminal, a virtual reality (VR) device, an augmented reality (AR) device, a smart point of sale (POS) machine, a customer-premises equipment (CPE), a wireless terminal device in industrial control, a smart home device (such as a refrigerator, a television, an air conditioner, an electricity meter, etc.), a smart robot, a mechanical arm, a workshop device, a wireless terminal device in unmanned driving, a wireless terminal device in telemedicine, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, a wireless terminal device in a smart home, a flying device (such as a smart robot, a hot air balloon, a drone, an airplane), etc. The terminal device can also be other devices with terminal device function, for example, the terminal device can also be a device that assumes a terminal device function in D2D communication.

[0083] Embodiments of the present application do not limit the device form of the terminal device, and the device for implementing the function of the terminal device can be a terminal device, or can be a device capable of supporting the terminal device to implement the function, such as a chip system. The device can be installed in the terminal device or used with the terminal device. In embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices.

[0084] The network device 101 can also be referred to as a satellite, a high-altitude platform, a high-altitude aircraft, or a satellite base station. The network device 101 provides a communication service to the terminal device 102, and the network device 101 can also be connected to a core network device. The network device is used to help the terminal device to implement wireless access.

[0085] In a possible scenario, the network device 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, a network device in a non-terrestrial network (NTN) communication system, i.e., can be deployed on a high-altitude platform or a satellite, etc. The network device can be a macro base station, a micro base station, or an indoor station, a relay node or a donor node, or a wireless controller in a CRAN scenario. The network device can also be a device that plays a base station function in device to device (D2D) communication, vehicle-to-everything (V2X) communication, unmanned aerial vehicle communication, and machine communication. Optionally, the network device can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the network device in the V2X technology can be a road side unit (RSU).

[0086] All or part of the functions of the network device in the present application can also be implemented by software functions running on hardware, or by virtualized functions instantiated on a platform (such as a cloud platform). The network device in the present application can also be a logical node, a logical module, or software that can implement all or part of the functions of the network device.

[0087] In another possible scenario, a terminal device accesses a network device to perform wireless access. The network device can be a base station, or a network device in a base station, or a network device in a core network. The network device can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can be included in the same network element, for example, in a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, for example, in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It can be understood that the network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a network device in a radio access network (RAN), or the CU can be divided into a network device in a core network (CN), which is not limited here.

[0088] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in an ORAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0089] Taking 5G as an example, a 5G satellite communication system architecture is shown in FIG. 2. A ground terminal device accesses a 5G new air interface network, and a 5G base station is deployed on a satellite and connected to a ground core network through a wireless link. At the same time, there is a wireless link between satellites to complete signaling interaction and user data transmission between base stations. The devices and interfaces in FIG. 2 are described as follows:

[0090] 5G core network: user access control, mobility management, session management, user security authentication, charging, etc. It is composed of multiple functional units, which can be divided into control plane and data plane functional entities. Access and mobility management unit (AMF), responsible for user access management, security authentication, and mobility management. User plane unit (UPF) is responsible for managing user plane data transmission, traffic statistics, and other functions. Session management function (SMF), mainly used for session management in mobile networks, such as session establishment, modification, and release.

[0091] Ground station: responsible for forwarding signaling and application data between satellite base station and 5G core network.

[0092] 5G new radio: wireless link between terminal device and base station.

[0093] Xn interface: interface between 5G base stations, mainly used for signaling interaction such as handover.

[0094] NG interface: interface between 5G base station and 5G core network, mainly interacting with core network non-access layer (NAS) signaling, etc., and user application data.

[0095] In the embodiments of the present application, the form of the network device is not limited, and the device for realizing the function of the network device can be a network device; or it can be a device capable of supporting the network device to realize the function, such as a chip system. The device can be installed in the network device or used with the network device.

[0096] The following describes the technical solutions provided by the embodiments of the present application, taking the device for realizing the function of the network device as an example, that is, a satellite, to describe the technical solutions provided by the embodiments of the present application. It can be understood that when the scheme provided by the embodiments of the present application is applied to a terrestrial communication system, the actions performed by the satellite can be applied to the base station or the network device to perform. In addition, the satellite described above can be a stationary satellite, a non-stationary satellite, an artificial satellite, a low-orbit satellite, a medium-orbit satellite, and a high-orbit satellite, etc., and the embodiments of the present application are not limited specifically.

[0097] In order to facilitate understanding of the content of the present scheme, the following will explain some terms involved in the embodiments of the present application, so as to facilitate understanding by those skilled in the art, and this part is only for the convenience of understanding, and cannot be regarded as a specific limitation of the present application.

[0098] 1. Domain name server

[0099] 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.

[0100] 2. Recursive server

[0101] 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.

[0102] 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.

[0103] 3. Iterative Domain Name Server

[0104] 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.

[0105] 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.

[0106] Recursive and iterative DNS servers each have their own applicable scenarios. Recursive servers are usually used for ordinary user domain name resolution requests because they can provide complete resolution results, and users do not need to care about specific details of the resolution. Iterative servers are often used in more advanced network configurations, such as servers of an internet service provider (ISP), which need to handle a large number of resolution requests and can better control the resolution process.

[0107] 4. Authoritative DNS server

[0108] An authoritative DNS is a server that resolves domain names through authorization from a higher level, and it can also transfer resolution authorization to others. For example, a COM top-level server can authorize the authoritative server of the http: / / dns.com domain name to be http: / / NS.ABC.COM, and http: / / NS.ABC.COM can also transfer authorization to http: / / NS.DDD.COM, so that http: / / NS.DDD.COM becomes the actual authoritative server of http: / / ABC.COM. Usually, the results of user domain name resolution can be derived from an authoritative DNS. For example, the authoritative DNS server of http: / / dns.com is http: / / ns1.dns.com and http: / / ns2.dns.com. Then, the specific IP address or other records of a domain name can be queried through http: / / ns1.dns.com.

[0109] 5. Forwarding DNS server

[0110] A forwarding DNS server is responsible for accepting user queries and returning results to the user. However, the results are not obtained through the standard domain name resolution process, but are directly forwarded to the user from a recursive DNS. It also has a caching function and is mainly used in a situation where there is no direct internet connection, but a recursive DNS can be connected to. In this case, using a forwarding DNS is more appropriate.

[0111] 6. Recursive query and iterative query

[0112] Recursive query and iterative query are two different query methods, mainly used in DNS systems, but their working methods and application scenarios are different. The specific introduction is as follows:

[0113] Recursive query: usually initiated by a client (such as a user's computer or device). In this query mode, the client makes a complete query request to the local DNS server, which contains the domain name to be resolved. The local DNS server is responsible for querying from the root DNS server, and then querying down in turn to obtain the IP address corresponding to the domain name. If the domain name server cannot directly answer, the domain name server will recursively query up and down in each branch of the domain tree, and finally return the query result to the client. During the query process, the client will be completely in a waiting state.

[0114] Iterative query: also known as re-direction, when the server uses iterative query, other servers can return a best query point prompt or host address. If the best query point contains the host address to be queried, the address information is returned; if the server cannot directly query the host address, it will query in turn according to the prompt until the server gives a prompt containing the host address to be queried. Generally, each direction will be closer to the root server (upward), and after searching the root domain name server, it will again search downward according to the prompt.

[0115] The main difference between the two query modes is that recursive query is performed on the local DNS server, while iterative query is performed on the root domain name server. In practical applications, recursive query is usually used for queries from the request host to the local DNS server, while iterative query is used for query requests from the local DNS server to the root domain name server.

[0116] It should be understood that the definitions of the above technical terms are only examples. For example, as technology continues to evolve, the scope of the above definitions can also change, and the embodiments of the present application are not limited.

[0117] First, in order to facilitate the understanding of the embodiments of the present application, the technical problems to be solved by the present application are further analyzed and proposed.

[0118] Before a user initiates an HTTP request / application access to an application server, the network can first convert the domain name / URL / host name of the application server into an IP address, which can be referred to as DNS resolution. The user receives the IP address from the DNS resolution, and can initiate a TCP connection to the application server corresponding to the IP address.

[0119] The current satellite DNS architecture is shown in FIG. 3, in which the base station gNB, core network element UPF, and DNS cache server are deployed on the satellite (the non-terrestrial network part shown in FIG. 3), such as a LEO low earth orbit satellite. In the DNS resolution process, the terminal device can be regarded as a DNS client, and the LDNS can be regarded as a DNS server. Specifically:

[0120] 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.

[0121] 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.

[0122] 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.

[0123] For the LDNS server mentioned above, please refer to Figure 4, which is a schematic diagram of the structure of an LDNS server provided in an embodiment of this application. As shown in Figure 4, domain name resolution is performed from top to bottom according to the characteristics 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 by local name servers (LDNS servers), which are mostly managed by one or more operators, Internet access service providers, etc.

[0124] The DNS resolution under the aforementioned satellite DNS architecture may have the following technical problems:

[0125] 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.

[0126] Technical problem 2: The existing edge computing solution of the operator is applied to the allocation of the IP address of the application server based on the geographical location of the UPF accessed by the terminal equipment of the LDNS deployed by the province. Generally, the IP address of the server closest to the terminal equipment is selected to accelerate the application experience of the terminal equipment and reduce the access path delay. However, the UPF is on the satellite, and the LDNS cannot directly map the geographical location on the ground, that is, the IP address of the application server cannot be directly matched according to the address of the UPF, thereby increasing the access delay of the terminal equipment application.

[0127] Therefore, how to reduce the access delay of the terminal equipment application in the NTN communication scenario is an urgent technical problem to be solved.

[0128] The technical problem to be solved by the embodiments of the present application is to reduce the access delay of the terminal equipment application in the NTN communication scenario.

[0129] Based on the above, the present application provides a communication method, which will be described below through each embodiment. It should be understood that in each embodiment of the present application, the terms and / or descriptions of different embodiments have consistency and can be mutually referred to if there is no special description and logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship. These methods can be used in combination. The technical solutions provided by the present application are not limited to the processes described below. Further, the description of the scene in the embodiments of the present application is only for example, and does not limit the solutions of the embodiments of the present application to only be used in the described scene. It is also applicable to scenes with similar problems.

[0130] First, the network architecture of the embodiments of the present application is introduced. Please refer to FIG. 5, which is a schematic diagram of the architecture of a satellite DNS provided by the embodiments of the present application. Compared with the current satellite DNS architecture shown in FIG. 3, the satellite DNS architecture shown in FIG. 5 can add an LDNS-NT server deployed on the satellite. The structure of the LDNS-NT server can be the same as that of the LDNS server shown in FIG. 4, that is, it can include a cache server and a recursive server, and the functions implemented can also be the same as those of the LDNS server shown in FIG. 4. Optionally, the DNS resolution records stored by the LDNS-NT server can be periodically synchronized to the LDNS-NT server on the satellite by the LDNS-T server or the LDNS-NT server on the satellite can actively and periodically initiate an update request to the LDNS-T server on the ground.

[0131] As shown in FIG. 5, the architecture of the satellite DNS can include a terminal device (such as a UE), an access network device (such as a gNB on LEO), a core network element UPF, an LDNS-NT server, an LDNS-T server, a ground scheduling center, and an application server. Among them, the access network device, the core network element UPF, and the LDNS-NT server are deployed on the satellite, and the terminal device, the LDNS-T server, and the ground scheduling center are deployed on the ground. The application server can be deployed on the satellite, or can be deployed on the ground, or can be deployed on the satellite and the ground according to the application strategy as needed, for example, the application server is deployed on the satellite, and the corresponding IP address is 1, and for example, the application server is deployed on the ground, and the corresponding IP address is 2.

[0132] It can be understood that if the satellites on which the access network device, the core network element UPF, and the LDNS-NT server are deployed 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 routing between the satellites is reachable.

[0133] In combination with the network architecture of FIG. 5 described above, a communication method provided by an embodiment of the present application is described below. It can be understood that the first network element, the UPF, and the second network element are taken as an example of the execution subject of the interaction in the present application, but the present application does not limit the execution subject of the interaction. For example, the first network element in the embodiment of the present application (the corresponding embodiment is described below) can be a terminal device in the LDNS-NT server shown in FIG. 5, the method executed by the LDNS-NT server in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the LDNS-NT server, and can also be realized by a logical node, a logical module, or software that can realize all or part of the function of the LDNS-NT server. The UPF in the present embodiment can be the UPF in the network architecture shown in FIG. 5, the method executed by the UPF in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the UPF, and can also be realized by a logical node, a logical module, or software that can realize all or part of the function of the UPF. The second network element in the present embodiment can be the LDNS-T server in the network architecture shown in FIG. 5, the method executed by the LDNS-T server in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the LDNS-T server, and can also be realized by a logical node, a logical module, or software that can realize all or part of the function of the LDNS-T server. Among them, the satellite can be a stationary satellite, a non-stationary satellite, an artificial satellite, a low-orbit satellite, a medium-orbit satellite, and a high-orbit satellite, and the like, which is not limited in the embodiment of the present application.

[0134] Please refer to FIG. 6, which is an interaction diagram of a communication method provided in an embodiment of the present application. As shown in FIG. 6, the communication method can include at least the following steps.

[0135] S601: The terminal device sends a second domain name resolution request to the UPF, and the second domain name resolution request carries a domain name requested by the terminal device to be resolved. Correspondingly, the UPF receives the second domain name resolution request from the terminal device.

[0136] The terminal device can initiate an application layer domain name resolution request, that is, request the network side to obtain an IP address corresponding to a domain name requested by the terminal device to be resolved in the domain name resolution request. For example, the terminal device sends a second domain name resolution request to the UPF. The second domain name resolution request can be used to request resolution of an IP address corresponding to a domain name requested by the terminal device to be resolved, and the IP address is used for the terminal device to request access to an application corresponding to the IP address. The second domain name resolution request carries the domain name requested by the terminal device to be resolved. Optionally, the second domain name resolution request can also carry a source address, a destination address, and an ID of an application requested by the terminal device to be accessed. For example, the source address is an address of the terminal device, and the destination address is an address of the UPF or an IP address of an operator's LDNS server. For example, the address can be an IP address, a media access control (MAC) address, and the like, wherein the IP address can be an IPv4 address or an IPv6 address, and can also be other IP addresses in future wireless communication development.

[0137] In the embodiment of the present application, the address can also be understood as an identifier of a device. For example, the identifier of the terminal device can include one or more of the following information: a subscription concealed identifier (SUCI), a subscription permanent identifier (SUPI), a 5G globally unique temporary identity (5G GUTI), a temporary mobile subscriber identity (TMSI), a 5G system temporary mobile subscriber identity (5GS TMSI), a generic public subscription identifier (GPSI), an EPC, a network identifier, identifier information indicating an application requestor, and the like.

[0138] Exemplarily, the application server can be an edge application server (EAS), which can be understood as an application server close to the terminal device in terms of the location of the terminal device and providing services for the application of the terminal device.

[0139] It should be noted that the signaling interaction between the terminal device and the core network element (for example, the UPF) can be transparently transmitted through the access network device RAN, which is not shown in FIG. 6. For another example, the signaling interaction between the terminal device and the UPF can be transparently transmitted through the access network device RAN or forwarded by the core network element access and mobility management function (AMF).

[0140] S602: The UPF determines the application label indication according to the second domain name resolution request.

[0141] After receiving the second domain name resolution request from the terminal device, the UPF can determine the application label indication according to the second domain name resolution request. Specifically, after receiving the second domain name resolution request, the UPF identifies the domain name in the second domain name resolution, matches and executes the user plane splitting rule / N4 session splitting rule (packet detect rule+forward action rule, which can also be understood as rule detection on the data packet of the second domain name resolution request), that is, the UPF obtains the application subscription data and / or user plane forwarding rule information, and the UPF can determine the application label indication according to the application subscription data and / or user plane forwarding rule information. In other words, the UPF can synchronize the subscription data of the application and the user plane splitting rule / N4 session splitting rule from the ground core network, and carry the application label indication together with the second domain name resolution request.

[0142] The UPF can determine the application label indication according to the application subscription data and / or the user plane forwarding rule information, which can be any of the following possible implementation manners:

[0143] The first possible implementation manner is that the UPF determines the application label indication according to the application subscription data. Specifically, the UPF can match the application requested to be accessed by the terminal device with the application subscription data, determine the deployment state of the application requested to be accessed by the terminal device, and thus determine the application label indication.

[0144] In a second possible implementation, the UPF determines the application label indication according to user plane forwarding rule information. Specifically, the UPF can obtain user plane forwarding rule information, which can be understood as a processing rule of the UPF for a received data packet (for example, a second domain name resolution request), and thus processes information of the received second domain name resolution request according to the user plane forwarding rule information. For example, the user plane forwarding rule information includes application deployment status, identification and labeling of data packets. After the UPF determines the application label indication according to the application deployment status, the UPF can add the determined application label indication in the second domain name resolution request.

[0145] In a third possible implementation, the UPF can determine the application label indication according to application subscription data and user plane forwarding rule information. Specifically, the UPF can obtain the application subscription data and the user plane forwarding rule information, match the application requested to be accessed by the terminal device with the application subscription data, determine the deployment status of the application requested to be accessed by the terminal device, and thus determine the application label indication. The UPF processes information of the received second domain name resolution request according to the user plane forwarding rule information. For example, the user plane forwarding rule information includes identification and labeling of data packets. After the UPF determines the application label indication according to the application subscription data, the UPF can add the determined application label indication in the second domain name resolution request.

[0146] The application label indication is used to indicate the deployment status of the application requested to be accessed by the terminal device. For example, the deployment status can include whether the application is deployed on a satellite, and optionally, information such as load status of an instance. For example, the application label indication can include "on_board" and "on_the_ground", where "on_board" can indicate that the application requested to be accessed by the terminal device is deployed on a satellite, and "on_the_ground" can indicate that the application requested to be accessed by the terminal device is deployed on the ground.

[0147] That is, the UPF can identify the application according to the ID or domain name of the application requested to be accessed by the terminal device, and compare the application with the subscription data to identify which applications are deployed on a satellite and which applications are deployed on the ground.

[0148] The UPF can obtain the application subscription data from a core network element user data management (UDM) / unified data repository (UDR). The UDM can be understood as a core network element mainly responsible for managing subscription data, user access authorization, and the like. The UDR can be understood as a core network element mainly responsible for access functions of types of data such as subscription data, policy data, and application data.

[0149] S603: The UPF sends a first domain name resolution request to the first network element, and the first domain name resolution request carries the domain name requested by the terminal device for resolution and an application label indication. Correspondingly, the first network element receives the first domain name resolution request from the UPF.

[0150] The first domain name resolution request is used to request resolution of an IP address corresponding to the domain name requested by the terminal device for resolution. The first domain name resolution request can also be referred to as a first DNS resolution request or a first DNS request, and the name of the first domain name resolution request is not limited in the embodiments of the present application. The domain name requested by the terminal device for resolution can also be understood as the domain name of the application server requested by the terminal device for resolution. The first network element can be understood as a destination network element corresponding to the IP address of the LDNS server of the operator carried in the second domain name resolution request.

[0151] The UPF sends the first domain name resolution request to the first network element, which can also be understood as that the UPF forwards the second domain name resolution request from the terminal device to the first network element. Unlike the second domain name resolution request that carries the domain name requested by the terminal device for resolution, the first domain name resolution request carries the domain name requested by the terminal device for resolution and the application label indication determined by the UPF. Optionally, the first domain name resolution request can also carry a source address, a destination address, and an ID of an application requested by the terminal device to access, and the like. 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 specific description of the address, reference can be made to S601 described above. Optionally, after receiving the second domain name resolution request, the UPF can perform network address transfer (NAT) mapping on the source address of the terminal device, for example, update the source address to the address of the UPF.

[0152] In a possible implementation, in the first domain name resolution request, the application label indication can be located after the domain name requested by the terminal device for resolution. In other words, in the first domain name resolution request packet, the field of the application label indication can be located after the field of the domain name requested by the terminal device for resolution. For example, the application label indication can be carried in the query name (queried host name) of the query area (queries) part of the message format of the first domain name resolution request.

[0153] S604: The first network element queries the IP address corresponding to the domain name according to the application label indication.

[0154] 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 according to the application label indication carried in the first domain name resolution request.

[0155] Specifically, the first network element can query the domain name requested by the terminal device to resolve and whether the application label indication matches the local cache record; in the case of matching, S605 can be executed, and in the case of not matching, S606-S609 can be executed. That is, the first network element can preferentially query the local cache record (such as the local DNS cache record) to see if it can be hit (that is, whether the application label indication and the domain name requested by the terminal device to resolve can find the IP address of the corresponding application server), in other words, whether the IP address corresponding to the domain name requested by the terminal device to resolve (that is, the IP address corresponding to the application requested by the terminal device to access) exists in the local DNS cache record. If it is hit / exists (that is, if it matches), S605 is executed, otherwise S606-S609 is executed, that is, the first domain name resolution request is recursively queried to the second network element on the ground to continue to query the IP address corresponding to the domain name requested by the terminal device to resolve.

[0156] Further optionally, in the case of not matching, before S606-S609 is executed, the first network element can also query whether the satellite / constellation where the first network element is located has an effective feeder connection connected to the ground through the preconfigured ephemeris information, if yes, S606-S609 can be executed, if not, the first network element can send a DNS resolution response to the terminal device, the DNS resolution response including one or more of a DNS resolution failure indication, a DNS resolution failure reason and / or suggestion information. The DNS resolution failure reason may, for example, be that the DNS resolution result cannot be obtained through the satellite network temporarily, and the suggestion information may, for example, be to suggest the terminal device to change the DNS resolution server address or to change to the ground network for DNS resolution (that is, to suggest the terminal device to initiate a domain name resolution request to the second network element).

[0157] It can be understood that the following S605 and S606-S609 are parallel optional steps.

[0158] It should be noted that, whether the first network element is locally resolved or the second network element on the ground is recursively acquired DNS resolution result, the following rules can be met: 1) If the application accessed by the terminal device is deployed on the satellite according to the application label indication in the first domain name resolution request, the IP address of the application server deployed on the satellite can be returned to the terminal device (such as the application server-IP address 1 shown in FIG. 5); 2) If the application accessed by the terminal device is not deployed on the satellite according to the application label indication in the first domain name resolution request, the IP address of the application server deployed on the ground can be returned to the terminal device (such as the application server-IP address 2 shown in FIG. 5). For example, if the application label indication is "on_board", 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 can preferentially match the IP address of the application server on the satellite for the terminal device; if the application label indication is "on_the_ground", 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 can preferentially match the IP address of the application server on the ground for the terminal device.

[0159] Based on S604, unlike the first network element preferentially querying the IP of the application server locally, the IP of the application server deployed on the satellite can be resolved into the IP of the last ground application server, which increases the time delay of the terminal device application access. In the embodiment of the application, the first network element can select the application server according to the deployment distribution of the application (such as whether there is deployment on the satellite) through the application label indication in the received first domain name resolution request. If the application accessed by the terminal device is deployed on the satellite, the application server on the satellite can be preferentially selected to serve the terminal device, so as to reduce the time delay of the terminal device application access in the NTN communication scenario.

[0160] It should be noted that the structure of the first network element can include a cache server and a recursive server, wherein the query of the IP address corresponding to the domain name requested by the terminal device by the first network element according to the application label indication in the first domain name resolution request can be performed by the cache server, and the sending of the third domain name resolution request by the first network element to the second network element in the following S606 can be performed by the recursive server, that is, the recursive query of the IP address corresponding to the domain name requested by the terminal device is continued.

[0161] S605: The first network element sends a domain name resolution result to the terminal device, and the domain name resolution result includes an IP address corresponding to the domain name. Correspondingly, the terminal device receives the domain name resolution result from the first network element.

[0162] Optionally, if the first network element forwards the first domain name resolution request to the second network element opposite to obtain the DNS resolution result, the method flow shown in FIG. 6 can further include the steps of S606-S609.

[0163] S606: The first network element sends a third domain name resolution request to the second network element, and the third domain name resolution request carries at least one of the domain name requested by the terminal device for resolution, the application label indication, and the identifier of the UPF and / or the FW. Correspondingly, the second network element receives the third domain name resolution request from the first network element.

[0164] 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, and the third domain name resolution request can be used to request resolution of the IP address corresponding to the domain name requested by the terminal device for resolution. The third domain name resolution request carries at least one of the domain name requested by the terminal device for resolution and the application label indication, and the identifier (such as the IP address) of the UPF and / or the FW carried in the first domain name resolution request.

[0165] After the second network element receives the third domain name resolution request from the first network element, it can initiate an iterative query. For details, please refer to FIG. 7, which is a schematic diagram of an iterative query provided by an embodiment of the present application. As shown in FIG. 7, the second network element can be a local domain name server (LDNS-T server), which can request DNS resolution results from the root domain name server, the top-level domain name server, and the authoritative domain name server in turn after receiving the third domain name resolution request. The authoritative domain name server can optionally direct the DNS resolution request to the ground dispatch center for further request for DNS resolution results through the CNAME technology.

[0166] It can be understood that if the DNS resolution result is obtained at one of the domain name servers, S609 can be executed.

[0167] S607: The second network element determines the ground gateway location corresponding to the UPF and / or the FW according to the mapping relationship between the UPF and / or the FW and the ground gateway location and the identifier of the UPF and / or the FW.

[0168] For example, the LDNS-T server sends a domain name resolution request to the ground dispatch center, and the domain name resolution request can include at least one of the domain name requested by the terminal device for resolution, the application label indication, and the identifier of the UPF and / or the FW. Optionally, the domain name resolution request can 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 dispatch center.

[0169] The ground dispatching center can obtain the mapping relationship between the UPF and / or FW and the ground gateway location, and determine the ground gateway location corresponding to the UPF and / or FW according to the identifier of the UPF and / or FW in the third domain name resolution request. The mapping relationship between the UPF and / or FW and the ground gateway location can be preconfigured by the operator. The identifier of the UPF and / or FW can be an identifier or address information allocated by the operator, and the mapping relationship with the payload satellite is also pre-allocated, so that the identifier of the payload satellite where the UPF and / or FW is located can be known. The ephemeris information can be maintained by the satellite network operator and delivered to the ground operator, and configured to the ground dispatching center by the ground operator. The satellite identifier and the feeder connection status of the ground station, the connection object (such as whether the feeder is valid and which ground station is connected when receiving the domain name resolution request) can be known from the ephemeris information.

[0170] S608: The second network element determines the 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 FW.

[0171] After the ground dispatching center determines the ground gateway location corresponding to the UPF and / or FW, the ground dispatching center can select an application server for the terminal device according to the ground gateway location corresponding to the UPF and / or FW, such as selecting the application server closest to the terminal device, or the application server closest to the terminal device and having the best service quality.

[0172] That is, the ground dispatching center can be configured with ephemeris information, and the satellite identifier where the UPF and / or FW is located and the ground gateway address connected by the satellite at this time can be known from the ephemeris information. The IP address of the application server closest to the ground gateway is found by scheduling and matching based on the geographical location information of the ground gateway.

[0173] Based on S608, the ground dispatching center can obtain the mapping relationship between the UPF and / or FW and the geographical location of the ground gateway, and can use this geographical location information to address the application server for the terminal device, so as to reduce the latency of application access by the terminal device in the NTN communication scenario.

[0174] S609: The second network element sends the domain name resolution result to the terminal device, and the domain name resolution result includes the IP address corresponding to the domain name. Correspondingly, the terminal device receives the domain name resolution result from the second network element.

[0175] It should be noted that, for S606-S609, the second network element can be the LDNS-T server and the ground dispatch center. In a possible implementation, the LDNS-T server and the ground dispatch center can be deployed separately or in one. The foregoing embodiment is described according to the separate deployment implementation, and if the deployment is in one, the flow can be further simplified, that is, the interaction between the LDNS-T server and the ground dispatch center can be the internal implementation of the second network element.

[0176] Through the embodiment shown in FIG. 6, a scheme for optimizing application access of a terminal device in an NTN communication scenario is provided. Unlike the first network element preferentially querying the IP of the local cache application server, the IP of the application server deployed on the satellite can be resolved into the IP of the last ground application server, thereby increasing the time delay of the terminal device application access. In the embodiment of the application, the first network element can select the application server according to the deployment distribution of the application (such as whether there is deployment on the satellite) through the application label indication in the received first domain name resolution request. If the application requested by the terminal device is deployed on the satellite, the application server on the satellite can be preferentially selected to serve the terminal device, thereby reducing the time delay of the terminal device application access in the NTN communication scenario.

[0177] It can be understood that, in order to implement the functions in the foregoing embodiments, the first network element, the UPF and the second network element include corresponding hardware structures and / or software modules for implementing the functions. Those skilled in the art should easily understand that, in combination with the units and method steps of the examples described in the embodiments disclosed in the application, the application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is implemented in hardware or computer software driven hardware depends on the specific application scenario and design constraints of the technical solution.

[0178] FIGS. 8 and 9 are structural schematic diagrams of possible communication apparatuses provided by the embodiments of the application. The communication apparatuses can be used to implement the functions of the first network element, the UPF or the second network element in the foregoing method embodiments, and thus can also achieve the beneficial effects possessed by the foregoing method embodiments. The communication apparatus can be the first network element, the UPF or the second network element, or a device (for example, a chip, or a chip system, or a circuit) in the first network element, the UPF or the second network element. As shown in FIG. 8, the communication apparatus 800 at least includes a transceiver unit 801 and a processing unit 802. The communication apparatus 800 is used to implement the functions of the first network element, the UPF or the second network element in the foregoing method embodiment shown in FIG. 6.

[0179] When the communication apparatus 800 is used to implement the functions of the first network element in the method embodiment shown in FIG. 6, the transceiver unit 801 is configured to receive a first domain name resolution request, the first domain name resolution request including an application label.

[0180] The transceiver unit 801 is configured to receive 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 by the terminal device to resolve, the IP address being used for the terminal device to request access to an application corresponding to the IP address; wherein the first domain name resolution request carries the domain name requested by the terminal device to resolve and an application label indication, the application label indication being used to indicate a deployment state of the application requested by the terminal device to access, the deployment state including whether the application is deployed on a satellite.

[0181] The processing unit 802 is configured to query the IP address corresponding to the domain name according to the application label indication and the domain name.

[0182] Optionally, the processing unit 802 queries the IP address corresponding to the domain name according to the application label indication and the domain name, and is specifically configured to: query whether the domain name and the application label indication match a local cache record.

[0183] In the case of matching, the transceiver unit 801 is further configured to send 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,

[0184] In the case of not matching, the transceiver unit 801 is further configured to send 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 the IP address corresponding to the domain name requested by the terminal device to resolve, the IP address being used for the terminal device to request access to the application corresponding to the IP address, the third domain name resolution request carrying the domain name requested by the terminal device to resolve and the application label indication carried in the first domain name resolution request.

[0185] Optionally, in the case of not matching, before the transceiver unit 801 forwards the first domain name resolution request to the second network element, the processing unit 802 is further configured to query whether there is a valid feeder connection connecting the ground on the satellite where the first network element is located.

[0186] If yes, the transceiver unit 801 is further configured to send the third domain name resolution request to the second network element; or,

[0187] If no, the transceiver unit 801 is further configured to send a DNS resolution response to the terminal device.

[0188] Optionally, the DNS resolution response includes DNS resolution failure reason and / or suggestion information.

[0189] Optionally, the transceiver unit 801 receives the first domain name resolution request from the terminal device, and is specifically configured to: receive the first domain name resolution request from the terminal device through a UPF.

[0190] Optionally, the application label indication is located after the domain name requested by the terminal device in the first domain name resolution request.

[0191] When the communication apparatus 800 is configured to implement the function of the UPF in the method embodiment shown in FIG. 6:

[0192] The transceiver unit 801 is configured to receive a second domain name resolution request from a terminal device, the second domain name resolution request carrying a domain name requested by the terminal device to be resolved, the second domain name resolution request being used to request resolution of an IP address corresponding to the domain name requested by the terminal device to be resolved, the IP address being used for the terminal device to request access to an application corresponding to the IP address.

[0193] The processing unit 802 is configured to determine 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 including whether the application is deployed on a satellite.

[0194] Optionally, the processing unit 802 determines the application label indication according to the second domain name resolution request, specifically configured to: obtain application subscription data and / or user plane forwarding rule information; determine the application label indication according to the application subscription data and / or the user plane forwarding rule information; the application label indication is used to indicate the 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.

[0195] Optionally, the transceiver unit 801 is further configured to send a first domain name resolution request to a first network element, the first domain name resolution request being used to request resolution of an IP address corresponding to the domain name requested by the terminal device to be resolved, the first domain name resolution request carrying the domain name requested by the terminal device to be resolved and the application label indication, the first network element being deployed on a satellite.

[0196] Optionally, the application label indication is located after the domain name requested by the terminal device in the first domain name resolution request.

[0197] When the communication apparatus 800 is configured to implement the function of the UPF in the method embodiment shown in FIG. 6:

[0198] The transceiver unit 801 is configured to receive a third domain name resolution request, the third domain name resolution request carrying a domain name requested by a terminal device to be resolved, an application label indication, an identifier of a UPF and / or a 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 an IP address corresponding to the domain name requested by the terminal device to be resolved, 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.

[0199] The processing unit 802 is configured to determine the ground gateway position corresponding to the UPF and / or FW according to the mapping relationship between the UPF and / or FW and the ground gateway position and the identifier of the UPF and / or FW.

[0200] The processing unit 802 is further configured to determine the application server corresponding to the application requested to be accessed by the terminal device according to the ground gateway position corresponding to the UPF and / or FW.

[0201] Optionally, the processing unit 802 is further configured to acquire the mapping relationship between the UPF and / or FW and the ground gateway position.

[0202] Optionally, 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.

[0203] For more details of the transceiver unit 801 and the processing unit 802, please refer to the related description in the method embodiment shown in FIG. 6.

[0204] Please refer to FIG. 9, which is a structural schematic diagram of another communication apparatus provided by the embodiment of the present application. The apparatus 110 is configured to implement the function of the network element of the present application, for example, the network element can be the first network element, the UPF or the second network element. The apparatus 110 can be the network element, or a device capable of being installed in the network element, or a device capable of being used with the network element, without limitation, for example, the device can be a chip or a chip system. As shown in FIG. 9, the apparatus 110 includes an interface 111 and a processor 112. Optionally, the processor 112 is configured to execute a program 114. The processor 112 can store the program 114, or acquire the program 114 from other devices or other devices (for example, from the memory 113 or from a third-party website, etc.). Optionally, the apparatus 110 includes a memory 113. The memory 113 is configured to store a program 115. The program 115 can be pre-stored or subsequently loaded. Optionally, the memory 113 can also be configured to store necessary data. These components work together to provide various functions described in the present application.

[0205] The processor 112 includes one or more processors, which are in combination a computing device. The processor 112 can include one or more of a microprocessor, a microcontroller, a digital signal processor (DSP), a digital signal processing device (DSPD), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device (PLD), gate logic, transistor logic, discrete hardware circuits, processing circuitry, or other suitable hardware, firmware, and / or combinations thereof configured to perform the various functions described in the present application. The processor 112 can be a general purpose processor or a special purpose processor. For example, the processor 112 can be a baseband processor or a central processor. The baseband processor can be used to process communication protocols and communication data. The central processor can be used to execute software programs and process data in the software programs.

[0206] The interface 111 can include any suitable hardware or software for enabling communication with one or more computer devices, such as the network elements of the present application. For example, in some embodiments, the interface 111 can include terminals and / or pins for coupling wires for wired connections or wireless transceivers for wireless connections. In some embodiments, the interface 111 can include a transmitter, a receiver, a transceiver, and / or an antenna. The interface can be configured to enable communication between computer devices, such as the network elements of the present application, using any available protocol, such as 3GPP standard protocols.

[0207] A program in the present application refers to software in a broad sense. The software can be program code, programs, subprograms, instruction sets, codes, code segments, software modules, application programs, software applications, etc. The program can be run in a processor and / or a computer to perform various functions and / or processes described in the present application.

[0208] The memory 113 can store necessary data required when the processor 112 executes software. The memory 113 can be implemented using any suitable storage technology. For example, the memory 113 can be any available storage media that can be accessed by a processor and / or computer. Non-limiting examples of storage media have RAM, ROM, electrically erasable programmable ROM (EEPROM), compact disc read-only memory (CD-ROM), blu-ray disc (BD), removable media, optical storage, magnetic storage, flash memory, register, state memory, remotely mounted memory, local or remote storage components, or any other possible storage medium that can carry or store software, data, or information and be accessed by a processor / computer.

[0209] The memory 113 and the processor 112 can be separately arranged or integrated together. The processor 112 can read information from the memory 113, store and / or write information in the memory. The memory 113 can be integrated in the processor 112. The processor 112 and the memory 113 can be arranged in an integrated circuit (for example, an application-specific integrated circuit (ASIC)). The integrated circuit can be arranged in a network element or other network node of the present disclosure.

[0210] Optionally, the apparatus 110 in the embodiments of the present application can be used to execute the methods described in the embodiments of the present application.

[0211] The embodiments of the present application also provide a computer readable storage medium, having stored thereon a computer program, which, when executed by a processor, can implement the processes related to the first network element, the UPF and the second network element in the communication method provided by the above method embodiments.

[0212] The embodiments of the present application also provide a computer program product, which, when running on a computer or a processor, causes the computer or the processor to execute one or more steps in any of the above communication methods. The constituent modules of the above-mentioned devices, if realized in the form of software function units and sold or used as independent products, can be stored in the computer readable storage medium.

[0213] The embodiments of the present application further provide a chip system, comprising at least one processor and a communication interface, the communication interface and the at least one processor are interconnected through a line, and the at least one processor is configured to run computer programs or instructions to execute part or all of the steps of any one of the above-mentioned corresponding method embodiments. The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0214] The embodiments of the present application further provide a communication system, which comprises a first network element, a UPF and a second network element, and the specific description can be referred to the above-mentioned method.

[0215] It should be understood that the memory mentioned in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a hard disk drive (HDD), a solid-state drive (SSD), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM) and direct rambus RAM (DR RAM). The memory can be any other medium capable of carrying or storing desired program code in the form of instructions or data structures and capable of being accessed by a computer, but is not limited to this. The memory in the embodiments of the present application can also be a circuit or any other device capable of realizing the storage function, used for storing program instructions and / or data.

[0216] It should also be understood that the processor mentioned in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0217] 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, discrete hardware component, the memory (storage module) is integrated in the processor.

[0218] It should be noted that the memory described herein is intended to include, but not limited to, these and any other suitable types of memory.

[0219] It should be understood that in various embodiments of the present application, the size of the sequence number of each process described above does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0220] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments provided herein can be realized in electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed 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 the present application.

[0221] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0222] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic. The division of the units is merely a logical function division. There can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0223] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0224] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can be a physically independent unit, or two or more units can be integrated into a unit.

[0225] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts that essentially contribute to the technology or the parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk, and various program code storage media.

[0226] The steps in the method embodiments of the present application can be adjusted, combined and deleted according to actual needs.

[0227] The modules / units in the device embodiments of the present application can be combined, divided and deleted according to actual needs.

[0228] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present 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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