DNS request resolution method, communication device and communication system

Abstract

The present application provides a DNS request resolution method, a communication device, and a communication system. The method includes: a diversion network element receives a DNS request from a terminal device; the diversion network element determines at least one service network according to a first rule and configuration information of at least one local network; the diversion network element sends a DNS request to a PSA corresponding to at least one service network; the diversion network element receives response information corresponding to the at least one DNS request, and the response information includes an IP address of an application server; the diversion network element sends the IP address of the first application server to the terminal device, and the IP address of the application server received by the diversion network element includes the IP address of the first application server. Based on this solution, the diversion network element can select one or more service networks based on the first rule and the configuration information of the local network. Since the selected service network is deployed with a DNS server, the situation where the resolution cannot be achieved can be avoided, thereby improving the resolution success rate of the DNS request.

Description

Technical Field

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

[0002] When a terminal device wants to request the service of an application, such as when a user wants to use WeChat service or watch videos on the iQiyi APP, the user can click on the corresponding function module on the application to trigger the establishment of a user-side session between the terminal device and the network. The terminal device then sends a Domain Name System (DNS) request to the network. The request carries an application identifier. After receiving the DNS request, the diversion network element sends the DNS request to the DNS server of the local network or the central network for resolution to obtain the Internet Protocol (IP) address of the application server. The diversion network element then sends the IP address to the terminal device. The terminal device can access the corresponding application server based on the IP address to obtain the data content of the application server, thereby obtaining the service of the application.

[0003] In the process of resolving DNS requests, how to improve the resolution success rate of DNS requests is currently a problem that needs to be solved. Summary of the invention

[0004] The present application provides a DNS request resolution method, a communication device and a communication system to improve the efficiency of resolving DNS requests.

[0005] In a first aspect, an embodiment of the present application provides a method for resolving a DNS request, comprising: a diversion network element receives a DNS request from a terminal device, the DNS request includes an application identifier, and the DNS request is used to request an Internet Protocol IP address of an application server corresponding to the application identifier; the diversion network element determines at least one service network according to a first rule and configuration information of at least one local network, the service network is deployed with a DNS server, the configuration information of the local network includes capability information of the local network, the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server, and the first rule is a determination rule for the service network; the diversion network element sends the DNS request to a protocol data unit anchor PSA corresponding to the at least one service network; the diversion network element receives response information corresponding to the at least one DNS request, the response information includes the IP address of the application server corresponding to the application identifier; the diversion network element sends the IP address of the first application server to the terminal device, and the IP address of the application server received by the diversion network element includes the IP address of the first application server.

[0006] Through the above scheme, the diversion network element can select one or more service networks based on the configured first rule and the configuration information of the local network, and send the received DNS request to the PSA corresponding to the selected one or more service networks. Since DNS servers are deployed in the selected service networks, situations where resolution cannot be achieved can be avoided, thereby improving the success rate of DNS request resolution.

[0007] In a possible implementation method, the first rule is preconfigured on the offloading network element; or the offloading network element receives the first rule from a session management network element.

[0008] In a possible implementation method, the configuration information of the at least one local network is pre-configured on the offload network element; or the offload network element receives the configuration information of the at least one local network from a session management network element.

[0009] In a possible implementation method, the first rule is determined based on at least one of a local DNS server deployment of the local network, a resolution capability of the local DNS server, application servers included in the local network, and a location of the local network.

[0010] In a possible implementation method, the first rule includes at least one of the following rules:

[0011] 1) If the at least one local network does not deploy a local DNS server, the DNS request is sent to the central network;

[0012] 2) Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network.

[0013] 3) Sending the DNS request to one or more local networks in the at least one local network where a local DNS server is deployed.

[0014] In a possible implementation method, the capability information of the local network is also used to indicate whether the local DNS server supports recursive DNS resolution when a local DNS server is deployed in the local network;

[0015] The first rule also includes at least one of the following rules:

[0016] 4) If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, select a local network from them and send the DNS request to the selected local network;

[0017] 5) If only one of the at least one local network has a local DNS server deployed that supports recursive DNS resolution, the DNS request is sent to the local network;

[0018] 6) If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, the DNS request is sent to the multiple local networks;

[0019] 7) If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, select a local network from them and send the DNS request to the selected local network;

[0020] 8) If only one of the at least one local network has a local DNS server deployed that does not support recursive DNS resolution, the DNS request is sent to the local network;

[0021] 9) If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, the DNS request is sent to the multiple local networks.

[0022] In a possible implementation method, the capability information of the local network is further used to indicate information of an application server deployed in the local network; and the first rule further includes at least one of the following rules:

[0023] 10) If there are multiple local networks in the at least one local network that are deployed with the application server corresponding to the application identifier, and the multiple local networks are deployed with local DNS servers, select a local network from the at least one local network, and send the DNS request to the selected local network;

[0024] 11) If there is only one local network in the at least one local network that is deployed with the application server corresponding to the application identifier, and the local network is deployed with a local DNS server, sending the DNS request to the local network;

[0025] 12) If one or more local networks in the at least one local network have deployed an application server corresponding to the application identifier, and none of the one or more local networks has deployed a local DNS server, the DNS request is sent to the central network;

[0026] 13) If the at least one local network does not deploy the application server corresponding to the application identifier, the DNS request is sent to the central network.

[0027] In a possible implementation method, the configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used by the diversion network element to select a local network closest to the terminal device from the at least one local network.

[0028] Based on this solution, an IP address of an application server closest to the terminal device can be obtained, which can reduce latency and thus improve user experience.

[0029] In a possible implementation method, the IP address of the application server received by the diversion network element includes multiple IP addresses, and the first application server is an application server that meets the distance requirement from the terminal device among the application servers corresponding to the multiple IP addresses. For example, the application server that meets the distance requirement from the terminal device may be an application server that is closest to the terminal device, or an application server that is less than a preset threshold from the terminal device.

[0030] Based on this solution, an IP address of an application server closest to the terminal device can be obtained, which can reduce latency and thus improve user experience.

[0031] In a second aspect, an embodiment of the present application provides a communication method, including: a session management network element determines a first rule based on at least one of the local DNS server deployment of the local network, the resolution capability of the local DNS server, the application servers included in the local network, and the location of the local network; the session management network element determines the local network that the terminal device can access; the session management network element sends the configuration information of the local network that the terminal device can access and the first rule to the diversion network element, the configuration information of the local network includes the capability information of the local network, and the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server.

[0032] In a third aspect, an embodiment of the present application provides a communication device, which may be a shunting network element or a chip for a shunting network element. The device has the function of implementing any implementation method of the first aspect. The function may be implemented by hardware or by executing corresponding software implementation by hardware. The hardware or software includes one or more modules corresponding to the above functions.

[0033] In a fourth aspect, an embodiment of the present application provides a communication device, which may be a session management network element, or a chip for a session management network element. The device has the function of implementing the second aspect. The function may be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions.

[0034] In a fifth aspect, an embodiment of the present application provides a communication device, comprising a processor and a memory; the memory is used to store computer execution instructions, and when the device is running, the processor executes the computer execution instructions stored in the memory so that the device executes any implementation method as described in the first to second aspects above.

[0035] In a sixth aspect, an embodiment of the present application further provides a chip system, comprising: a processor, configured to execute any implementation method of the first aspect to the second aspect above.

[0036] In a seventh aspect, an embodiment of the present application provides a communication device, comprising a unit or means for executing each step of any implementation method of the first aspect to the second aspect above.

[0037] In an eighth aspect, an embodiment of the present application provides a communication device, including a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and execute any implementation method of the first to second aspects above. The processor includes one or more.

[0038] In a ninth aspect, an embodiment of the present application provides a communication device, including a processor, which is connected to a memory and is used to call a program stored in the memory to execute any implementation method of the first aspect to the second aspect. The memory can be located inside the device or outside the device. And the processor includes one or more.

[0039] In the tenth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein instructions are stored in the computer-readable storage medium, and when the computer-readable storage medium is run on a computer, the processor executes any implementation method of the first to second aspects mentioned above.

[0040] In the eleventh aspect, an embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is run, any implementation method of the above-mentioned first to second aspects is executed.

[0041] In a twelfth aspect, an embodiment of the present application further provides a communication system, including: a session management network element, configured to determine a first rule based on at least one of a local DNS server deployment of a local network, a resolution capability of a local DNS server, an application server included in the local network, and a location of the local network; determine a local network that a terminal device can access; and send configuration information of the local network that the terminal device can access and the first rule to a diversion network element, wherein the configuration information of the local network includes capability information of the local network, and the capability information of the local network is used to indicate whether a local DNS server is deployed in the local network. The diversion network element is configured to receive the configuration information of the local network and the first rule from the session management network element. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a communication system provided in an embodiment of the present application;

[0043] Figure 2(a) is a schematic diagram of the 5G network architecture;

[0044] FIG2( b ) is another schematic diagram of a 5G network architecture;

[0045] Figure 3 is an example diagram of multiple PSA scenarios;

[0046] Figure 4 A schematic diagram of a DNS request resolution method provided in an embodiment of the present application;

[0047] Figure 5 A schematic diagram of a communication device provided in an embodiment of the present application;

[0048] Figure 6 A schematic diagram of another communication device provided in an embodiment of the present application;

[0049] Figure 7 A schematic diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operation method in the method embodiment can also be applied to the device embodiment or the system embodiment. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0051] To solve the problems mentioned in the background technology, Figure 1 As shown, the present application provides a communication system, which includes a traffic distribution network element and a session management network element.

[0052] The session management network element is used to determine a first rule based on at least one of the deployment of a local DNS server in a local network, the resolution capability of the local DNS server, the application servers included in the local network, and the location of the local network; determine a local network that a terminal device can access; and send configuration information of the local network that the terminal device can access and the first rule to a diversion network element, wherein the configuration information of the local network includes capability information of the local network, and the capability information of the local network is used to indicate whether a local DNS server is deployed in the local network. The diversion network element is used to receive the configuration information of the local network and the first rule from the session management network element.

[0053] In a possible implementation method, the diversion network element is further used to receive a DNS request from the terminal device, the DNS request includes an application identifier, and the DNS request is used to request the Internet Protocol IP address of the application server corresponding to the application identifier; according to the first rule and the configuration information of the local network, at least one service network is determined, and the service network is deployed with a DNS server; the DNS request is sent to the protocol data unit anchor PSA corresponding to the at least one service network; response information corresponding to the at least one DNS request is received, and the response information includes the IP address of the application server; the IP address of the first application server is sent to the terminal device, and the IP address of the application server corresponding to the application identifier received by the diversion network element includes the IP address of the first application server. Among them, the deployment of the DNS server in the service network includes the following scenarios: the DNS server may be deployed in the service network, or may be deployed on the UPF / PSA serving the service network, or may be deployed between the UPF / PSA serving the service network and the service network. The deployment location of the DNS server is not limited, and the service network can be a local network / edge network or a central network.

[0054] In a possible implementation method, the first rule includes at least one of the following rules:

[0055] 1) If the at least one local network does not deploy a local DNS server, the DNS request is sent to the central network;

[0056] 2) Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network.

[0057] 3) Sending the DNS request to one or more local networks in the at least one local network where a local DNS server is deployed.

[0058] In a possible implementation method, the capability information of the local network is further used to indicate whether the local DNS server supports recursive DNS resolution when the local network is deployed with a local DNS server; and the first rule further includes at least one of the following rules:

[0059] 4) If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, select a local network from them and send the DNS request to the selected local network;

[0060] 5) If only one of the at least one local network has a local DNS server deployed that supports recursive DNS resolution, the DNS request is sent to the local network;

[0061] 6) If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, the DNS request is sent to the multiple local networks;

[0062] 7) If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, select a local network from them and send the DNS request to the selected local network;

[0063] 8) If only one of the at least one local network has a local DNS server deployed that does not support recursive DNS resolution, the DNS request is sent to the local network;

[0064] 9) If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, the DNS request is sent to the multiple local networks.

[0065] In a possible implementation method, the capability information of the local network is further used to indicate information of an application server deployed in the local network; and the first rule further includes at least one of the following rules:

[0066] 10) If there are multiple local networks in the at least one local network that are deployed with the application server corresponding to the application identifier, and the multiple local networks are deployed with local DNS servers, select a local network from the at least one local network, and send the DNS request to the selected local network;

[0067] 11) If there is only one local network in the at least one local network that is deployed with the application server corresponding to the application identifier, and the local network is deployed with a local DNS server, sending the DNS request to the local network;

[0068] 12) If one or more local networks in the at least one local network have deployed an application server corresponding to the application identifier, and none of the one or more local networks has deployed a local DNS server, the DNS request is sent to the central network;

[0069] 13) If the at least one local network does not deploy the application server corresponding to the application identifier, the DNS request is sent to the central network.

[0070] In a possible implementation method, the configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used by the diversion network element to select a local network closest to the terminal device from the at least one local network.

[0071] In a possible implementation method, the IP address of the application server received by the diversion network element includes multiple IP addresses, and the first application server is an application server that meets the distance requirement from the terminal device among the application servers corresponding to the multiple IP addresses.

[0072] In a possible implementation method, the configuration information of the local network also includes priority information of the local network, and the priority information is used by the offload network element to select a local network with the highest priority from the at least one local network.

[0073] The specific implementation of the above solution will be described in detail in the subsequent method implementation examples and will not be repeated here.

[0074] Figure 1 The system shown can be used in the fifth generation (5th generation, 5G) network architecture shown in Figure 2 (a) or Figure 2 (b). Of course, it can also be used in future network architectures, such as the sixth generation (6th generation, 6G) network architecture, etc., which is not limited in this application.

[0075] For example, assuming Figure 1 The communication system shown is applied to a 5G network architecture, as shown in FIG2( a ), which is a schematic diagram of a 5G network architecture. Figure 1 The network element or entity corresponding to the session management network element in the example may be a session management function (SMF) network element in the 5G network architecture shown in FIG. 2( a). Figure 1 The network element or entity corresponding to the offload network element in the flow chart may be a user plane function (UPF) network element in the 5G network architecture shown in FIG. 2( a).

[0076] For example, assuming Figure 1 The communication system shown is applied to a 5G network architecture, as shown in FIG2( b ), which is a schematic diagram of a 5G network architecture. Figure 1 The network element or entity corresponding to the session management network element in the example may be the SMF network element in the 5G network architecture shown in FIG. 2( a). Figure 1 The network element or entity corresponding to the diversion network element in the diagram may be an uplink classifier (ULCL) network element in the 5G network architecture shown in FIG. 2( a).

[0077] The 5G network architecture shown in Figure 2(a) may include three parts, namely, the terminal equipment part, the data network (DN) and the operator network part. The functions of some of the network elements are briefly introduced below.

[0078] The operator network may include one or more of the following network elements: authentication server function (AUSF) network element, network exposure function (NEF) network element, policy control function (PCF) network element, unified data management (UDM), unified data repository (UDR), application function (AF) network element, access and mobility management function (AMF) network element, SMF network element, radio access network (RAN) equipment and UPF network element, etc. In the above operator network, the part other than the radio access network part can be called the core network part.

[0079] In a specific implementation, the terminal device in the embodiment of the present application may be a device for realizing a wireless communication function. The terminal device may be a user equipment (UE), an access terminal, a terminal unit, a terminal station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a wireless communication device, a terminal agent or a terminal device in a 5G network or a future evolved public land mobile network (PLMN). The access terminal may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device or a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The terminal may be mobile or fixed.

[0080] The above-mentioned terminal device can establish a connection with the operator network through the interface provided by the operator network (such as N1, etc.), and use the data and / or voice services provided by the operator network. The terminal device can also access the DN through the operator network, use the operator services deployed on the DN, and / or services provided by a third party. Among them, the above-mentioned third party may be a service provider other than the operator network and the terminal device, and can provide other data and / or voice services to the terminal device. Among them, the specific form of the above-mentioned third party can be determined according to the actual application scenario, and is not limited here.

[0081] RAN is a subnetwork of the operator network and an implementation system between the service node and the terminal device in the operator network. To access the operator network, the terminal device must first pass through the RAN, and then connect to the service node of the operator network through the RAN. The RAN device in this application is a device that provides wireless communication functions for the terminal device, and the RAN device is also called an access network device. The RAN device in this application includes but is not limited to: the next generation base station (g nodeB, gNB) in 5G, evolved node B (evolved node B, eNB), radio network controller (radio network controller, RNC), node B (node ​​B, NB), base station controller (base station controller, BSC), base transceiver station (base transceiver station, BTS), home base station (for example, home evolved nodeB, or home node B, HNB), baseband unit (baseBand unit, BBU), transmission point (transmitting and receiving point, TRP), transmission point (transmitting point, TP), mobile switching center, etc.

[0082] The AMF network element mainly performs functions such as mobility management and access authentication / authorization. In addition, it is also responsible for transmitting user policies between the UE and the PCF.

[0083] The SMF network element mainly performs functions such as session management, execution of control policies issued by PCF, selection of UPF, and allocation of UE IP addresses.

[0084] The UPF network element, as the interface UPF with the data network, completes functions such as user plane data forwarding, session / flow-level billing statistics, and bandwidth limitation.

[0085] UDM network element is mainly responsible for managing contract data, user access authorization and other functions.

[0086] UDR is mainly responsible for the storage and access of contract data, policy data, application data and other types of data.

[0087] NEF network element is mainly used to support the opening of capabilities and events.

[0088] The AF network element mainly transmits the requirements of the application side to the network side, such as Quality of Service (QoS) requirements or user status event subscriptions. The AF can be a third-party functional entity or an application service deployed by an operator, such as the IP Multimedia Subsystem (IMS) voice call service.

[0089] The PCF network element is mainly responsible for policy control functions such as session and service flow level billing, QoS bandwidth guarantee and mobility management, and UE policy decision-making.

[0090] AUSF network element: Mainly responsible for authenticating users to determine whether users or devices are allowed to access the network.

[0091] DN is a network outside the operator network. The operator network can access multiple DNs. Multiple services can be deployed on DN, which can provide data and / or voice services to terminal devices. For example, DN is the private network of a smart factory. The sensors installed in the workshop of the smart factory can be terminal devices. The control server of the sensors is deployed in DN, and the control server can provide services for the sensors. The sensors can communicate with the control server, obtain instructions from the control server, and transmit the collected sensor data to the control server according to the instructions. For another example, DN is the internal office network of a company. The mobile phones or computers of the company's employees can be terminal devices. The employees' mobile phones or computers can access information and data resources on the company's internal office network.

[0092] In the architecture shown in Figure 2(a), the interface names and functions between the various network elements are as follows:

[0093] 1) N7: The interface between PCF and SMF, used to send protocol data unit (PDU) session granularity and service data flow granularity control strategy.

[0094] 2) N15: The interface between PCF and AMF, used to issue UE policies and access control related policies.

[0095] 3) N5: The interface between AF and PCF, used for issuing application service requests and reporting network events.

[0096] 4) N4: The interface between SMF and UPF is used to transmit information between the control plane and the user plane, including the control of the forwarding rules, QoS control rules, traffic statistics rules, etc. for the user plane and the reporting of information on the user plane.

[0097] 5) N11: The interface between SMF and AMF, used to transfer PDU session tunnel information between RAN and UPF, transfer control messages sent to UE, transfer radio resource control information sent to RAN, etc.

[0098] 6) N2: The interface between AMF and RAN, used to transmit radio bearer control information from the core network side to the RAN.

[0099] 7) N1: The interface between AMF and terminal equipment, used to transmit QoS control rules to UE.

[0100] 8) N8: The interface between AMF and UDM is used for AMF to obtain access and mobility management related subscription data and authentication data from UDM, and AMF to register UE's current mobility management related information with UDM.

[0101] 9) N10: The interface between SMF and UDM, used by SMF to obtain session management related contract data from UDM, and SMF to register UE current session related information with UDM.

[0102] 10) N35: Interface between UDM and UDR, used by UDM to obtain user contract data information from UDR.

[0103] 11) N36: Interface between PCF and UDR, used by PCF to obtain policy-related contract data and application data-related information from UDR.

[0104] 12) N12: Interface between AMF and AUSF, used by AMF to initiate an authentication process to AUSF, which can carry SUCI as a contract identifier;

[0105] 13) N13: Interface between UDM and AUSF, used by AUSF to obtain the user authentication vector from UDM to execute the authentication process.

[0106] It is understandable that the above network element or function can be a network element in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). Optionally, the above network element or function can be implemented by one device, or by multiple devices, or a functional module in one device, which is not specifically limited in the embodiments of the present application.

[0107] The session management network element and user plane network element in this application can be the SMF and UPF (such as ULCL, PSA1, PSA2) in Figure 2 (a) or Figure 2 (b), or can be a network element with the functions of the above SMF and UPF in future communications such as 6G networks, which is not limited in this application. For the convenience of explanation, this application takes the session management network element and the user plane network element as the above SMF and UPF as an example for explanation.

[0108] In the 5G network architecture shown in Figure 2(a) above, there is only one UPF. Based on the above architecture, 5G also supports inserting one or more PDU Session Anchor (PSA) UPFs on the user plane path of a PDU session to support connection to the local network (or edge data network, or mobile edge computing (MEC) network, or local data network, or MEC), so that the terminal device can access the application in the local data network nearby. Among them, each PSA is a UPF.

[0109] Based on Figure 2(a), multiple UPFs can be introduced to obtain the 5G network architecture shown in Figure 2(b). Among them, some network elements in Figure 2(a) are not shown in Figure 2(b). The multiple UPFs introduced include: ULCL UPF, PSA UPF1 and PSAUPF-2. It should be noted that Figure 2(b) is only an example. In actual applications, there is no limit on the number of PSAs, which can be one, two or more than two.

[0110] In the embodiment of the present application, the branching network element may be a ULCL UPF, which may also be called ULCL, a branching point (BP), a BP UPF, etc., and is hereinafter referred to as ULCL.

[0111] In the embodiment of the present application, PSA UPF may also be referred to as UPF PSA or PSA, etc., and is hereinafter referred to as PSA. Therefore, the above-mentioned PSA UPF1 and PSA UPF2 may also be referred to as PSA1 and PSA2.

[0112] ULCL is used to distribute uplink data packets received from the terminal device to PSA1 or PSA2 according to the distribution rule, and to send downlink data packets received from PSA1 or PSA2 to the terminal device.

[0113] There is an N6 interface between PSA1 and DN. For example, the DN can be a DN located in a central data center (DC). In this case, PSA1 can also be called a center PSA (C-PSA) or a remote PSA. There is an N6 interface between PSA2 and a local DN. For example, the local DN can be a DN located in a local DC (i.e., a MEC network). In this case, PSA2 can also be called a local PSA (L-PSA).

[0114] When there is a UPF (such as PSA2) connected to the local DN at the location of the terminal device, the SMF can insert the UPF as an L-PSA into the session path so that the terminal device can access the application in the local DN nearby. Figure 2(b) above only shows one L-PSA (i.e., PSA2), and multiple L-PSAs can also be included in actual applications.

[0115] like Figure 3 As shown, it is an example diagram of multiple PSA scenarios. Among them, ULCL can connect to multiple L-PSAs, and the figure takes the connection of two L-PSAs (i.e., L-PSA1 and L-PSA2) as an example. In this example, L-PSA1 is connected to local network 1, L-PSA2 is connected to local network 2, and C-PSA is connected to the central network (also called central data network, central DC, remote network, remote data network, etc.). In addition, a DNS server is deployed in local network 1, no DNS server is deployed in local network 2, and a DNS server is deployed in the central network. Among them, the DNS server deployed in the local network can also be called an edge DNS server or a local DNS server. In the following, L-DNS is used to represent the local DNS server in the local network, and the DNS server deployed in the central network can also be called a center DNS server. In the following, C-DNS is used to represent the center DNS server in the center network.

[0116] In the existing network, L-DNS can be deployed together with UPF that provides services for the local network, for example, Figure 3 In the example, local network 1 can be deployed together with L-PSA1, local network 2 can be deployed together with L-PSA2, and ULCL can be deployed together with a certain L-PSA, such as ULCL is deployed together with L-PSA1.

[0117] The L-DNS deployed in the local network can be used to resolve DNS requests corresponding to application servers in the local network. The L-DNS deployed in the local network may be connected to the C-DNS server deployed in the central network (i.e., they can communicate with each other), or it may not be connected to the C-DNS deployed in the central network (i.e., they cannot communicate with each other).

[0118] When the terminal device wants to request the service of a certain application, such as the user wants to use WeChat service or watch videos using iQiyi APP, the user can click on the corresponding function module on the application to trigger the establishment of a user plane session between the terminal device and the network, and then the terminal device sends a DNS request to the network, which carries an application identifier (such as a fully qualified domain name (FQDN)). After receiving the DNS request, ULCL sends the DNS request to a PSA, such as L-PSA1, and then L-PSA1 sends the DNS request to the L-DNS in the local network 1. The L-DNS queries the IP address corresponding to the application identifier and sends the IP address to L-PSA1. L-PSA1 sends the IP address to ULCL, and ULCL sends the IP address to the terminal device through RAN, so that the terminal device can access the corresponding application server according to the IP address to obtain the data content of the application server, thereby obtaining the service of the application.

[0119] The IP address here is the IP address of the application server corresponding to the application identifier, which can be the IP address of the application server in the central network and / or the IP address in one or more local networks. For example, if the application is WeChat, the obtained IP address is the IP address of the WeChat application server. Generally, when a DNS server and an application server are deployed in a local network or a central network, the mapping relationship between the application identifier and the IP address of the application server is stored in the DNS server. Figure 3 Taking local network 1 as an example, if WeChat application server, iQiyi application server and Tencent application server are deployed in local network 1, the DNS server of local network 1 stores the mapping relationship between WeChat domain name and IP address of WeChat application server, the mapping relationship between iQiyi domain name and IP address of iQiyi application server and the mapping relationship between Tencent domain name and IP address of Tencent application server.

[0120] Generally, the application server of the same application can be deployed in the central network. At the same time, in order to provide users with nearby services and improve user experience, the application server can also be deployed in one or more local networks while the application server is deployed in the central network. Figure 3 For example, Tencent application server can be deployed in the central network, and Tencent application server can also be deployed in local network 1 and / or local network 2.

[0121] The following describes some possible situations and problems that may occur during an actual DNS request process.

[0122] When the ULCL receives a DNS request (which carries an application identifier), it needs to send the DNS request to a PSA. There are the following situations:

[0123] Scenario 1: No DNS server is deployed in the local network corresponding to PSA

[0124] refer to Figure 3 For example, ULCL sends a DNS request to L-PSA2, but the local network corresponding to L-PSA2 does not deploy a DNS server. Therefore, L-PSA2 cannot send the DNS request to the corresponding DNS server, resulting in the DNS request being unable to be resolved.

[0125] Scenario 2: A DNS server is deployed in the local network corresponding to PSA

[0126] When a DNS server is deployed in the local network corresponding to the PSA, the DNS server in the local network can resolve the DNS request. Depending on whether an application server corresponding to the application identifier in the DNS request is deployed in the local network, scenario 2 can be further divided into the following scenario 2.1 and scenario 2.2.

[0127] Scenario 2.1: The local network corresponding to the PSA has an application server corresponding to the application identifier in the DNS request.

[0128] refer to Figure 3 For example, ULCL sends a DNS request to L-PSA1. A DNS server is deployed in the local network corresponding to L-PSA1. Therefore, L-PSA1 can send the DNS request to the DNS server in local network 1, and the DNS server can resolve the DNS request.

[0129] When an application server corresponding to the application identifier in the DNS request is deployed in local network 1, the DNS server of local network 1 stores the correspondence between the application identifier and the IP address of the application server, so the DNS server can successfully resolve and obtain the IP address of the application server.

[0130] Scenario 2.2: The local network corresponding to the PSA does not have an application server corresponding to the application ID in the DNS request.

[0131] refer to Figure 3 For example, ULCL sends a DNS request to L-PSA1. A DNS server is deployed in the local network 1 corresponding to L-PSA1. Therefore, L-PSA1 can send the DNS request to the DNS server in the local network 1, and the DNS server can resolve the DNS request.

[0132] When the application server corresponding to the application identifier in the DNS request is not deployed in local network 1, the DNS server of local network 1 may not store the correspondence between the application identifier and the IP address of the application server, so the DNS server cannot successfully resolve the IP address of the application server.

[0133] For this scenario 2.2, the scenario 2.2 can be further divided into the following scenarios 2.2.1 and 2.2.2 according to whether there is a connection (i.e., interconnection) between the DNS server in the local network and the DNS server in the central network.

[0134] Scenario 2.2.1: There is a connection between the DNS server deployed in the local network and the DNS server deployed in the central network

[0135] When there is a connection between the DNS server deployed in the MEC and the DNS server deployed in the central network, if the DNS server in the local network fails to resolve the application identifier in the DNS request, the DNS request can be sent to the DNS server in the central network, and the DNS server in the central network resolves the application identifier in the DNS request. That is, in this case, the DNS server in the local network supports recursive resolution. The DNS server deployed in the central network does not specifically refer to Figure 3 The C-DNS in the text does not refer to the C-DNS in the text, but refers to a DNS server that has DNS resolution capability and has an interface with the DNS server in the local network. That is, after the DNS server in the local network sends a DNS request to the DNS server, the DNS server can resolve the DNS request.

[0136] Generally, the DNS server in the central network is deployed with the application server corresponding to the application identifier, so the resolution can be successful. In addition, the DNS server in the central network stores a mapping relationship between an application identifier and the IP addresses of multiple application servers, where the multiple application servers include application servers in the central network and application servers in the local network.

[0137] After the DNS server in the central network successfully resolves the application domain name, it sends the corresponding IP address to the DNS server deployed in the local network, which is then sent by the L-PSA corresponding to the local network to the ULCL and further to the terminal device.

[0138] It should be noted that, through this recursive method, the IP address resolved by the DNS server in the central network may not be the optimal IP address, that is, the application server corresponding to the IP address may not be the application server closest to or closer to the terminal device, which may lead to a poor user experience. In one implementation method, when the DNS server in the local network fails to resolve the application identifier in the DNS request, the DNS request can be sent to the DNS server in the central network, and the location information of the terminal device is also carried in the DNS request. In this way, the DNS server in the central network can resolve the DNS request based on the location information of the terminal device, and the resolved IP address is closer to the terminal device.

[0139] Scenario 2.2.2: There is no connection between the DNS server deployed in the local network and the DNS server deployed in the central network

[0140] In this case, the DNS server deployed in the local network cannot resolve the DNS request, and cannot request the DNS server deployed in the central network to resolve the DNS request, so the resolution fails.

[0141] The above are various situations that may occur when ULCL sends DNS requests to different PSAs. In principle, if the DNS server in the local network can resolve it, it should be resolved by the DNS server in the local network. This is because the DNS server in the local network can obtain an IP address of an application server that is closest to the terminal device. If it is resolved by the DNS server in the central network, on the one hand, due to the long path, it will cause delays. On the other hand, the application server corresponding to the IP address resolved by the DNS server in the central network may not be the application server closest to the terminal device, resulting in a poor user experience.

[0142] From the various scenarios analyzed above, it can be seen that, on the one hand, when ULCL sends the received DNS request to the corresponding PSA, it may ultimately fail to resolve the DNS request (such as the above scenario 1 and scenario 2.2.2), so that ULCL needs to reselect a PSA and send the DNS request to the PSA, resulting in signaling waste. On the other hand, if ULCL sends the DNS request to the central PSA at the beginning, the application server corresponding to the IP address resolved by the central DNS server may not be the application server closest to the terminal device, resulting in a poor user experience.

[0143] Therefore, how to improve the resolution efficiency of DNS requests (such as improving the resolution success rate, reducing the number of DNS requests, etc.) is to be solved in this application.

[0144] To solve the above mentioned problems, based on Figure 2(b) or Figure 3 The network architecture shown in Figure 4 As shown, the present application provides a method for resolving a DNS request. In this embodiment, the terminal device is a UE as an example for illustration. Figure 3 In practical applications, the embodiments of the present application are not limited to Figure 3 The network architecture shown in the figure. The embodiment of the present application can be applicable to the situation where one local network, two local networks or more than two local networks are deployed.

[0145] The method comprises the following steps:

[0146] Step 401, SMF configures the first rule and configuration information of the local network.

[0147] The local network here can be one or more local networks. The local network can also be called edge network, MEC network, MEC, local data network, etc.

[0148] The first rule (also referred to as a DNS request forwarding rule, a forwarding rule, a determination rule, etc.) may be configured on the SMF by an administrator through a network management system, or may be determined by the SMF. For example, the SMF determines the first rule based on at least one of the L-DNS deployment of the local network, the resolution capability of the L-DNS, the application servers included in the local network, and the location of the local network.

[0149] The configuration information of the local network may be configured on the SMF by the administrator through the network management system, or may be determined by the SMF. The configuration information of the local network at least includes the capability information of the local network, and the capability information of the local network is used to indicate whether the local network is deployed with L-DNS.

[0150] Optionally, the capability information of the local network is also used to indicate whether the L-DNS supports recursive DNS resolution when the local network is deployed with the L-DNS. Wherein, when there is an interface between the L-DNS and the C-DNS, the L-DNS supports recursive resolution.

[0151] Optionally, the capability information of the local network is also used to indicate information of an application server deployed in the local network.

[0152] Optionally, the configuration information of the local network also includes location information or service area information of the local network. The location information or service area information of the local network can be represented by a Tracking Area Indicator (TAI) to indicate the location of the local network.

[0153] Step 402: The UE creates a PDU session.

[0154] At this time, SMF has not yet inserted ULCL into the PDU session, and the current user plane path of the PDU session is: UE<->RAN<->C-PSA.

[0155] Step 403: SMF is inserted into ULCL.

[0156] The SMF may be inserted into the ULCL during the process of the UE creating a session, or may be dynamically inserted after the UE creates a session.

[0157] The triggering event that triggers SMF to insert ULCL may be: SMF detects UE movement, SMF receives a DNS request from C-PSA, or receives a notification from PCF, etc.

[0158] Step 404: SMF sends the first rule and the configuration information of the local network to the ULCL. Accordingly, the ULCL can receive the first rule and the configuration information of the local network.

[0159] SMF creates an N4 session between SMF and ULCL, and then sends the first rule and the configuration information of the local network to ULCL through the N4 session. ULCL can determine to send the received DNS request to the corresponding UPF based on the first rule and the configuration information of the local network. The UPF here can be L-PSA and / or C-PSA.

[0160] It should be noted that if the UE's current location has multiple local networks that can be accessed, that is, the UE's location is within the coverage of multiple local networks, the SMF sends the first rule and configuration information of multiple local networks to the ULCL.

[0161] As an implementation method, the SMF may determine a local network that the UE that creates the PDU session can access, and then send a first rule and configuration information of the local network that the UE can access to the ULCL.

[0162] Step 405: The ULCL configures the first rule and the configuration information of the local network.

[0163] After receiving the first rule and the configuration information of the local network, the ULCL configures the first rule and the configuration information of the local network on the ULCL.

[0164] After the first rule and the configuration information of the local network are configured on the ULCL, the ULCL may determine to which UPF the received DNS request is forwarded based on the first rule and the configuration information of the local network.

[0165] It should be noted that, as another implementation method, the first rule on the ULCL may also be preconfigured on the ULCL, for example, by an administrator through a network management system. When the first rule on the ULCL is preconfigured on the ULCL, there is no need to configure the first rule to the ULCL through the SMF.

[0166] As another implementation method, the configuration information of the local network on the ULCL may also be pre-configured on the ULCL, for example, it may be pre-configured by an administrator through a network management system. When the configuration information of the local network on the ULCL is pre-configured on the ULCL, it is not necessary to configure the configuration information of the local network to the ULCL through the SMF.

[0167] Step 406a: SMF inserts L-PSA1 and creates a tunnel between ULCL and L-PSA1.

[0168] like Figure 4 As shown, in order to establish a user plane connection with local network 1, L-PSA1 can be inserted into the user plane path of the UE's PDU session, and a tunnel between ULCL and L-PSA1 is created, thereby establishing a user plane path: UE<->RAN<->L-PSA1<->local network 1.

[0169] Step 406b: SMF inserts L-PSA2 and creates a tunnel between ULCL and L-PSA2.

[0170] like Figure 4 As shown, in order to establish a user plane connection with the local network 2, L-PSA2 can be inserted into the user plane path of the UE's PDU session, and a tunnel between ULCL and L-PSA2 is created, thereby establishing a user plane path: UE<->RAN<->L-PSA2<->local network 2.

[0171] Step 407: ULCL receives the DNS request.

[0172] The DNS request is sent by the UE to the RAN, and the RAN sends the DNS request to the ULCL.

[0173] The DNS request includes an application identifier, and the DNS request is used to request to query the IP address of the application server corresponding to the application identifier.

[0174] In step 408, the ULCL determines at least one service network for receiving the DNS request.

[0175] The service network here can be a local network or a central network. The service network is deployed with a DNS server.

[0176] For example, when the service network is a local network, L-DNS is deployed. Optionally, one or more application servers (i.e., local application servers) may also be deployed in the local network. Among them, a local network corresponds to one or more L-PSAs, or the one or more L-PSAs provide services for the local network. L-PSA and the local network may be deployed together or separately. Optionally, there is an interface between the L-DNS and the C-DNS of the central network, then the L-DNS supports recursive resolution, that is, the received DNS request may be forwarded to the L-DNS for resolution.

[0177] When the service network is a central network, C-DNS is deployed. Optionally, one or more application servers (i.e., central application servers) may also be deployed in the central network. Among them, one central network corresponds to one or more C-PSAs, or the one or more C-PSAs provide services for the central network. C-PSA and the central network may be deployed together or separately. Optionally, there is an interface between C-DNS and the L-DNS of one or more local networks. The C-DNS may receive a DNS request sent by the one or local network, and after resolving the DNS request, send the resolved IP address to the L-DNS of the local network.

[0178] In step 408, the ULCL determines which DNS server or servers in which networks are required to resolve the DNS request.

[0179] As an implementation method, the ULCL may determine at least one service network based on the first rule and configuration information of at least one local network, and further determine a PSA (such as an L-PSA and / or a C-PSA) corresponding to the at least one service network.

[0180] As an example, when the capability information of the local network in the configuration information of the local network configured on the ULCL is used to indicate whether the local network is deployed with an L-DNS, the first rule configured on the ULCL includes but is not limited to at least one of the following:

[0181] First rule 1: If no L-DNS is deployed in the local network accessible by the UE, the DNS request is sent to the central network.

[0182] That is, if the local network accessible to the UE does not deploy L-DNS, the DNS request is sent to the C-PSA corresponding to the central network, and the C-PSA sends the DNS request to the C-DNS of the central network for resolution.

[0183] Based on the first rule, the DNS request is not sent to the L-PSA corresponding to the local network where L-DNS is not deployed, but is directly sent to the C-PSA corresponding to the central network, which can improve the resolution success rate of the DNS request and thus improve the resolution efficiency.

[0184] First rule 2: send the DNS request to a local network in which the L-DNS is deployed among the local networks accessible to the UE, and to the central network. Optionally, priorities between the multiple local networks and the central network may be predefined, so that when the ULCL receives IP addresses from multiple networks, one may be selected from the received multiple IP addresses according to the priority.

[0185] Based on the first rule, since ULCL sends the received DNS requests to multiple local networks and to the central network instead of just to one local network or just to the central network, that is, it requests multiple service networks to resolve the DNS requests each time, the resolution success rate of the DNS requests can be improved, thereby improving the resolution efficiency.

[0186] First rule 3: send the DNS request to one or more local networks with L-DNS deployed in the local networks accessible to the UE. Optionally, priorities between the multiple local networks may be predefined, so that when the ULCL receives IP addresses from multiple networks, it may select one from the received multiple IP addresses according to the priority.

[0187] Based on the first rule, since ULCL sends the received DNS requests to multiple local networks and to the central network instead of just to one local network, that is, it requests multiple service networks to resolve the DNS requests each time, the resolution success rate of the DNS requests can be improved, thereby improving the resolution efficiency.

[0188] As an example, when the capability information of the local network in the configuration information of the local network configured on the ULCL is also used to indicate whether the L-DNS supports recursive DNS resolution when the local network is deployed with an L-DNS, the first rule configured on the ULCL may further include but is not limited to at least one of the following:

[0189] First rule 4: if there are multiple local networks that the UE can access and that are deployed with L-DNS supporting recursive DNS resolution, a local network is selected from them and the DNS request is sent to the selected local network.

[0190] That is, the DNS request is sent to the L-PSA corresponding to the selected local network, and the L-PSA sends the DNS request to the L-DNS in the local network for resolution.

[0191] Based on the first rule, on the one hand, since the ULCL only sends the received DNS request to the L-PSA corresponding to one local network, rather than to the L-PSAs corresponding to multiple local networks, that is, only one network is requested to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency. On the other hand, since the DNS request is sent to the L-PSA corresponding to the local network deployed with the L-DNS supporting recursive DNS resolution, the success rate of the DNS request resolution is improved, thereby further improving the DNS resolution efficiency.

[0192] First rule 5: If there is only one local network deployed with an L-DNS supporting recursive DNS resolution among the local networks accessible to the UE, the DNS request is sent to the local network.

[0193] That is, the ULCL sends the DNS request to the L-PSA corresponding to the local network, and the L-PSA sends the DNS request to the L-DNS in the local network for resolution.

[0194] Based on the first rule, on the one hand, since the ULCL only sends the received DNS request to the L-PSA corresponding to one local network, rather than to the L-PSAs corresponding to multiple local networks, that is, only one network is requested to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency. On the other hand, since the DNS request is sent to the L-PSA corresponding to the local network deployed with the L-DNS supporting recursive DNS resolution, the success rate of the DNS request resolution is improved, thereby further improving the DNS resolution efficiency.

[0195] First rule 6: If there are multiple local networks deployed with L-DNS supporting recursive DNS resolution among the local networks accessible to the UE, the DNS request is sent to the multiple local networks. Optionally, priorities between the multiple local networks can be predefined, so that when the ULCL receives IP addresses from multiple local networks, it can select one from the received multiple IP addresses according to the priority.

[0196] That is, the ULCL may send the DNS request to the L-PSAs corresponding to the multiple local networks respectively, and the L-PSAs respectively send the DNS request to the L-DNSs in the corresponding local networks for resolution.

[0197] Based on the first rule, on the one hand, since the ULCL sends the received DNS request to the L-PSAs corresponding to the multiple local networks respectively, instead of only sending it to the L-PSA corresponding to one local network, that is, requesting multiple local networks to resolve the DNS request each time, the success rate of DNS resolution can be improved, thereby improving the resolution efficiency. On the other hand, since the DNS request is sent to the L-PSA corresponding to the local network where the L-DNS supporting recursive DNS resolution is deployed, the success rate of the DNS request resolution is improved, thereby further improving the DNS resolution efficiency.

[0198] First rule 7: If there are multiple local networks that the UE can access and are deployed with L-DNS that does not support recursive DNS resolution, a local network is selected from them and the DNS request is sent to the selected local network.

[0199] That is, the ULCL sends the DNS request to the L-PSA corresponding to the selected local network, and the L-PSA sends the DNS request to the L-DNS in the local network for resolution. If the resolution fails, another local network can be selected from the above-mentioned multiple local networks, and the DNS request can be sent to the L-PSA corresponding to the other local network, and the L-PSA sends the DNS request to the L-DNS in the other local network for resolution. And so on, until the resolution is successful, or all resolutions fail, the DNS request is sent to the C-PSA corresponding to the central network, and the C-PSA sends the DNS request to the C-DNS of the central network for resolution.

[0200] Based on the first rule, since ULCL only sends the received DNS request to the L-PSA corresponding to one local network or the C-PSA corresponding to the central network, instead of sending it to the L-PSAs corresponding to multiple local networks, that is, it only requests one network to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency.

[0201] First rule 8: If there is only one local network deployed with an L-DNS that does not support recursive DNS resolution among the local networks accessible to the UE, the DNS request is sent to the local network.

[0202] That is, the ULCL sends the DNS request to the L-PSA corresponding to the local network, and the L-PSA sends the DNS request to the L-DNS in the local network for resolution. If the resolution fails, the DNS request is sent to the C-PSA corresponding to the central network, and the C-PSA sends the DNS request to the C-DNS of the central network for resolution.

[0203] Based on the first rule, since ULCL only sends the received DNS request to the L-PSA corresponding to one local network or the C-PSA corresponding to the central network, instead of sending it to the L-PSAs corresponding to multiple local networks, that is, it only requests one network to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency.

[0204] First rule 9: If there are multiple local networks deployed with L-DNS that does not support recursive DNS resolution among the local networks accessible to the UE, the DNS request is sent to the multiple local networks. Optionally, the priorities between the multiple local networks can be predefined, so that when the ULCL receives multiple IP addresses, it can select one from the received multiple IP addresses according to the priority.

[0205] That is, the ULCL sends the DNS request to the L-PSAs corresponding to the multiple local networks, and these L-PSAs send the DNS request to the L-DNS in the corresponding local networks for resolution. If the L-DNS corresponding to the above multiple local networks all fail to resolve, the DNS request is sent to the C-PSA corresponding to the central network, and the C-PSA sends the DNS request to the C-DNS of the central network for resolution.

[0206] Based on the first rule, since ULCL sends the received DNS requests to L-PSAs corresponding to multiple local networks instead of just sending them to the L-PSA corresponding to one local network, that is, it requests multiple local networks to resolve the DNS requests each time, the success rate of DNS resolution can be improved, thereby improving the resolution efficiency.

[0207] As an example, when the capability information of the local network in the configuration information of the local network configured on the ULCL is also used to indicate the information of the application server deployed on the local network, the information of the application server deployed on the local network is used to indicate which application servers are deployed in the local network, for example, the application identifier (such as FQDN) can be used to indicate the deployed application server. Then the first rule configured on the ULCL may further include but is not limited to at least one of the following:

[0208] First rule 10: If there are multiple local networks that the UE can access and the application servers corresponding to the application identifier are deployed therein, and the multiple local networks are deployed with L-DNS, then a local network is selected from the multiple local networks, and the DNS request is sent to the selected local network.

[0209] That is, the ULCL sends the DNS request to the L-PSA corresponding to the selected local network, and the L-PSA sends the DNS request to the L-DNS in the local network for resolution.

[0210] Based on the first rule, on the one hand, since the ULCL only sends the received DNS request to the L-PSA corresponding to one local network, rather than to the L-PSAs corresponding to multiple local networks, that is, only one network is requested to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency. On the other hand, since the local network is deployed with the application server corresponding to the application identifier in the DNS request, the success rate of the DNS request resolution is improved, thereby further improving the DNS resolution efficiency.

[0211] First rule 11: if there is only one local network in the local network accessible to the UE that has an application server corresponding to the application identifier deployed therein, and the local network has an L-DNS deployed therein, then the DNS request is sent to the local network.

[0212] That is, the ULCL sends the DNS request to the L-PSA corresponding to the local network, and the L-PSA sends the DNS request to the L-DNS in the local network for resolution.

[0213] Based on the first rule, on the one hand, since the ULCL only sends the received DNS request to the L-PSA corresponding to one local network, rather than to the L-PSAs corresponding to multiple local networks, that is, only one network is requested to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency. On the other hand, since the local network is deployed with the application server corresponding to the application identifier in the DNS request, the success rate of the DNS request resolution is improved, thereby further improving the DNS resolution efficiency.

[0214] First rule 12: if there are one or more local networks in the local networks accessible to the UE that have deployed an application server corresponding to the application identifier, and none of the one or more local networks has deployed an L-DNS, then a DNS request is sent to the central network.

[0215] That is, the ULCL sends the DNS request to the C-PSA corresponding to the central network, and the C-PSA sends the DNS request to the C-DNS in the central network for resolution. Optionally, the location information or service area information of the one or more local networks is also sent to the C-DNS, so that the C-DNS can select an application server closest to the UE based on the location information or service area information of the one or more local networks.

[0216] Based on the first rule, on the one hand, since the ULCL only sends the received DNS request to the C-PSA corresponding to the central network, rather than to the PSAs corresponding to multiple networks, that is, only one network is requested to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency. On the other hand, since the central network is deployed with the application server corresponding to the application identifier in the DNS request, the success rate of the DNS request resolution is improved, thereby further improving the DNS resolution efficiency. On the other hand, not sending the DNS request to the local network where the L-DNS is not deployed can reduce unnecessary signaling overhead.

[0217] First rule 13: If the local network accessible to the UE does not deploy the application server corresponding to the application identifier, the DNS request is sent to the central network.

[0218] That is, the ULCL sends the DNS request to the C-PSA corresponding to the central network, and the C-PSA sends the DNS request to the C-DNS of the central network for resolution.

[0219] Based on the first rule, on the one hand, since the ULCL only sends the received DNS request to the C-PSA corresponding to the central network, rather than to the PSAs corresponding to multiple networks (such as one or more local networks and the central network), that is, only one network is requested to resolve the DNS request each time, the number of DNS resolutions can be reduced, thereby reducing the signaling overhead and improving the resolution efficiency. On the other hand, since the C-DNS of the central network can resolve the IP address of the application server, the success rate of the DNS request resolution is improved, thereby further improving the DNS resolution efficiency.

[0220] Optionally, if the configuration information of the local network configured on the ULCL also includes location information or service area information of the local network, then in the above first rule, if the ULCL needs to select a local network from multiple local networks, the ULCL can select a local network closest to the UE from the multiple local networks based on the location information or service area information of the local network.

[0221] Optionally, if the configuration information of the local network configured on the ULCL also includes priority information of the local network, and the priority information is used by the ULCL to select a local network with the highest priority from at least one local network, then in the above-mentioned first rule, if the ULCL needs to select a local network from multiple local networks, the ULCL can select a local network from multiple local networks based on the priority information of the local network.

[0222] Optionally, if according to the first rule above, it is determined to send the DNS request to C-DNS, the ULCL may also carry the location information of the terminal device in the DNS request, so that C-DNS can resolve the DNS request based on the location information of the terminal device, and the resolved IP address is closer to the terminal device.

[0223] It should be noted that, if multiple first rules are configured on the ULCL, the priorities among these first rules may be preset.

[0224] It should be noted that the above first rule can be configured based on UE granularity, that is, the first rules configured for different UEs may be the same or different. Alternatively, the above first rule can be configured based on each UPF granularity, that is, the first rules configured for different UEs served by the same UPF are the same, but the first rules configured for different UEs served by different UPFs may be the same or different.

[0225] Steps 409a to 409b below are optional steps. If it is determined in step 408 that the service network for receiving the DNS request includes local network 1, then the following steps 409a and 409b are performed. If it is determined in step 408 that the service network for receiving the DNS request does not include local network 1, then the following steps 409a and 409b are not performed.

[0226] Step 409a, ULCL sends a DNS request to L-PSA1 corresponding to local network 1. Accordingly, L-PSA1 can receive the DNS request.

[0227] refer to Figure 4 After receiving the DNS request, L-PSA1 sends the DNS request to the L-DNS in the local network 1 for resolution.

[0228] When the L-DNS in the local network 1 successfully resolves the DNS request, that is, obtains the IP address of the application server corresponding to the application identifier in the DNS request, the L-DNS in the local network 1 sends the IP address to L-PSA1, and then L-PSA1 sends the IP address to ULCL, and then ULCL sends the IP address to RAN, and RAN sends the IP address to UE.

[0229] When the L-DNS in the local network 1 fails to resolve, if there is an interface between the L-DNS in the local network 1 and the C-DNS in the central network, the DNS request can be sent to the C-DNS for resolution, and then the C-DNS sends the resolution result (that is, the IP address of the application server) to the L-DNS in the local network 1, and then the L-DNS in the local network 1 sends the IP address to L-PSA1, L-PSA1 sends the IP address to ULCL, and then ULCL sends the IP address to RAN, and RAN sends the IP address to UE.

[0230] Step 409b: L-PSA1 sends response information to ULCL. Accordingly, ULCL can receive the response information.

[0231] It should be noted that when the response information contains an IP address (which can be obtained by L-DNS resolution of local network 1 or C-DNS resolution), it indicates that L-PSA1 successfully resolves the DNS request. When the response information does not contain an IP address, it indicates that L-PSA1 fails to resolve the DNS request.

[0232] The following steps 410a to 410b are optional steps. If it is determined in the above step 408 that the service network for receiving the DNS request includes a central network, the following steps 410a to 410b are performed. If it is determined in the above step 408 that the service network for receiving the DNS request does not include a central network, the following steps 410a to 410b are not performed.

[0233] Step 410a: ULCL sends a DNS request to the C-PSA corresponding to the central network. Correspondingly, the C-PSA may receive the DNS request.

[0234] refer to Figure 4 After receiving the DNS request, C-PSA sends the DNS request to the C-DNS of the central network for resolution. Generally, the central network is deployed with an application server corresponding to the application identifier, so the resolution can be successful. In addition, the C-DNS stores a mapping relationship between an application identifier and the IP addresses of multiple application servers, where the multiple application servers include application servers located in the central network and application servers located in the local network.

[0235] After C-DNS successfully resolves the application domain name, it sends the corresponding IP address to C-PSA, C-PSA sends the IP address to ULCL, ULCL sends the IP address to RAN, and RAN sends the IP address to UE.

[0236] Step 410b: C-PSA sends response information to ULCL. Correspondingly, ULCL can receive the response information.

[0237] It should be noted that when the response information contains an IP address, it indicates that C-DNS successfully resolves the DNS request. When the DNS reply does not contain an IP address, it indicates that C-DNS fails to resolve the DNS request.

[0238] Step 411: If the ULCL receives multiple IP addresses, it determines one IP address from them.

[0239] For example, if ULCL sends a DNS request to multiple UPFs (such as one or more L-PSAs, C-PSAs), it will receive a response message from each UPF. Some response messages carry IP addresses (i.e., resolution is successful), and some response messages do not carry IP addresses (i.e., resolution fails). If ULCL receives multiple IP addresses, it selects one IP address from them (called the IP address of the first application server).

[0240] As an implementation method, the first application server may be an application server that is closest to the UE.

[0241] Step 412: ULCL sends the IP address to the UE. Accordingly, the UE can receive the IP address.

[0242] That is, the ULCL sends the IP address of the first application server to the UE.

[0243] Through the above scheme, ULCL can select one or more service networks based on the configured first rule and the configuration information of the local network, and send the received DNS request to the PSA corresponding to the selected one or more service networks. For example, when the DNS request is sent to multiple selected service networks, the resolution success rate of the DNS request can be improved. For another example, when the DNS request is sent to a local network where a DNS server is deployed, or to a local network where a DNS server with recursive resolution capability is deployed, the resolution success rate can also be improved. Therefore, the above scheme can improve the success rate of DNS resolution. At the same time, the IP address of an application server closest to the terminal device can also be obtained, which can reduce latency and thus improve user experience.

[0244] The above mainly introduces the solution provided by the present application from the perspective of the interaction between various network elements. It can be understood that in order to realize the above functions, the above-mentioned network elements include hardware structures and / or software modules corresponding to the execution of various functions. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed in this document, the present invention can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0245] It can be understood that, in the above-mentioned method embodiments, the steps or operations implemented by the access network device can also be implemented by components (such as chips or circuits) configured in the access network device, and the steps or operations implemented by the user plane network element can also be implemented by components (such as chips or circuits) configured in the user plane network element.

[0246] refer to Figure 5 , is a schematic diagram of a communication device provided in an embodiment of the present application. The device is used to implement the above Figure 4 The steps performed by the corresponding shunt network element (ie, ULCL) in the embodiment are as follows: Figure 5 As shown, the device 500 includes a receiving unit 510 , a sending unit 520 and a processing unit 530 .

[0247] The receiving unit 510 is used to receive a DNS request from a terminal device, the DNS request includes an application identifier, and the DNS request is used to request the Internet Protocol IP address of the application server corresponding to the application identifier; and receive response information corresponding to the at least one DNS request, the response information includes the IP address of the application server corresponding to the application identifier. The processing unit 530 is used to determine at least one service network according to a first rule and configuration information of at least one local network, the service network is deployed with a DNS server, the configuration information of the local network includes capability information of the local network, the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server, and the first rule is a determination rule for the service network. The sending unit 520 is used to send the DNS request to the protocol data unit anchor PSA corresponding to the at least one service network; and send the IP address of the first application server to the terminal device, and the IP address of the application server received by the diversion network element includes the IP address of the first application server.

[0248] In a possible implementation method, the first rule is preconfigured on the offloading network element; or, the receiving unit 510 is further configured to receive the first rule from a session management network element.

[0249] In a possible implementation method, the configuration information of the at least one local network is pre-configured on the offload network element; or, the receiving unit 510 is further configured to receive the configuration information of the at least one local network from a session management network element.

[0250] In a possible implementation method, the first rule is determined based on at least one of a local DNS server deployment of the local network, a resolution capability of the local DNS server, application servers included in the local network, and a location of the local network.

[0251] In a possible implementation method, the first rule includes at least one of the following rules:

[0252] 1) If the at least one local network does not deploy a local DNS server, the DNS request is sent to the central network;

[0253] 2) Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network.

[0254] 3) Sending the DNS request to one or more local networks in the at least one local network where a local DNS server is deployed.

[0255] In a possible implementation method, the capability information of the local network is also used to indicate whether the local DNS server supports recursive DNS resolution when a local DNS server is deployed in the local network;

[0256] The first rule also includes at least one of the following rules:

[0257] 4) If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, select a local network from them and send the DNS request to the selected local network;

[0258] 5) If only one of the at least one local network has a local DNS server deployed that supports recursive DNS resolution, the DNS request is sent to the local network;

[0259] 6) If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, the DNS request is sent to the multiple local networks;

[0260] 7) If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, select a local network from them and send the DNS request to the selected local network;

[0261] 8) If only one of the at least one local network has a local DNS server deployed that does not support recursive DNS resolution, the DNS request is sent to the local network;

[0262] 9) If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, the DNS request is sent to the multiple local networks.

[0263] In a possible implementation method, the capability information of the local network is further used to indicate information of an application server deployed in the local network; and the first rule further includes at least one of the following rules:

[0264] 10) If there are multiple local networks in the at least one local network that are deployed with the application server corresponding to the application identifier, and the multiple local networks are deployed with local DNS servers, select a local network from the at least one local network, and send the DNS request to the selected local network;

[0265] 11) If there is only one local network in the at least one local network that is deployed with the application server corresponding to the application identifier, and the local network is deployed with a local DNS server, sending the DNS request to the local network;

[0266] 12) If one or more local networks in the at least one local network have deployed an application server corresponding to the application identifier, and none of the one or more local networks has deployed a local DNS server, the DNS request is sent to the central network;

[0267] 13) If the at least one local network does not deploy the application server corresponding to the application identifier, the DNS request is sent to the central network.

[0268] In a possible implementation method, the configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used to select a local network closest to the terminal device from the at least one local network.

[0269] In a possible implementation method, the IP address of the application server received by the receiving unit 510 includes multiple IP addresses, and the first application server is an application server that meets the distance requirement from the terminal device among the application servers corresponding to the multiple IP addresses.

[0270] Optionally, the communication device 500 may further include a storage unit for storing data or instructions (also referred to as code or program), and each of the above units may interact or couple with the storage unit to implement the corresponding method or function. For example, the processing unit 530 may read the data or instructions in the storage unit so that the communication device implements the method in the above embodiment.

[0271] It should be understood that the division of the units in the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And the units in the device can all be implemented in the form of software calling through processing elements; they can also be all implemented in the form of hardware; some units can also be implemented in the form of software calling through processing elements, and some units can be implemented in the form of hardware. For example, each unit can be a separately established processing element, or it can be integrated in a certain chip of the device. In addition, it can also be stored in the memory in the form of a program, and called and executed by a certain processing element of the device. The function of the unit. In addition, all or part of these units can be integrated together, or they can be implemented independently. The processing element described here can also be a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each unit above can be implemented by an integrated logic circuit of hardware in the processor element or in the form of software calling through a processing element.

[0272] In one example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, such as one or more application specific integrated circuits (ASIC), or one or more digital singnal processors (DSP), or one or more field programmable gate arrays (FPGA), or a combination of at least two of these integrated circuit forms. For another example, when the unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call a program. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0273] The receiving unit 510 is an interface circuit of the device, which is used to receive signals from other devices. For example, when the device is implemented in a chip, the receiving unit 510 is an interface circuit of the chip used to receive signals from other chips or devices.

[0274] The sending unit 520 is an interface circuit of the device, which is used to send signals to other devices. For example, when the device is implemented in a chip, the sending unit 520 is an interface circuit of the chip used to send signals to other chips or devices.

[0275] refer to Figure 6 , is a schematic diagram of a communication device provided in an embodiment of the present application. The device is used to implement the above Figure 4 The steps performed by the corresponding session management network element (ie, SMF) in the embodiment are as follows: Figure 6 As shown, the device 600 includes a transceiver unit 610 and a processing unit 620 .

[0276] The processing unit 620 is used to determine a first rule based on at least one of the deployment of a local DNS server in the local network, the resolution capability of the local DNS server, the application servers included in the local network, and the location of the local network; and determine a local network that the terminal device can access. The transceiver unit 610 is used to send configuration information of the local network that the terminal device can access and the first rule to the offload network element, wherein the configuration information of the local network includes capability information of the local network, and the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server.

[0277] Optionally, the communication device 600 may further include a storage unit for storing data or instructions (also referred to as code or program), and each of the above units may interact or couple with the storage unit to implement the corresponding method or function. For example, the processing unit 620 may read the data or instructions in the storage unit so that the communication device implements the method in the above embodiment.

[0278] It should be understood that the division of the units in the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And the units in the device can all be implemented in the form of software calling through processing elements; they can also be all implemented in the form of hardware; some units can also be implemented in the form of software calling through processing elements, and some units can be implemented in the form of hardware. For example, each unit can be a separately established processing element, or it can be integrated in a certain chip of the device. In addition, it can also be stored in the memory in the form of a program, and called and executed by a certain processing element of the device. The function of the unit. In addition, all or part of these units can be integrated together, or they can be implemented independently. The processing element described here can also be a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each unit above can be implemented by an integrated logic circuit of hardware in the processor element or in the form of software calling through a processing element.

[0279] In one example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, such as one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of at least two of these integrated circuit forms. For another example, when the unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a general-purpose processor, such as a CPU or other processor that can call a program. For another example, these units can be integrated together and implemented in the form of a SOC.

[0280] The above transceiver unit 610 is an interface circuit of the device, which is used to send signals to other devices or receive signals from other devices. For example, when the device is implemented in the form of a chip, the transceiver unit 610 is an interface circuit of the chip used to send signals to other chips or devices or to receive signals from other chips or devices.

[0281] refer to Figure 7 , is a schematic diagram of a communication device provided in an embodiment of the present application, which is used to implement the operation of the session management network element or the diversion network element in the above embodiments. Figure 7 As shown, the communication device includes: a processor 710 and an interface 730. Optionally, the communication device also includes a memory 720. The interface 730 is used to implement communication with other devices.

[0282] The method performed by the session management network element or the diversion network element in the above embodiment can be implemented by the processor 710 calling the program stored in the memory (which can be the memory 720 in the session management network element or the diversion network element, or it can be an external memory). That is, the session management network element or the diversion network element may include a processor 710, and the processor 710 executes the method performed by the session management network element or the diversion network element in the above method embodiment by calling the program in the memory. The processor here can be an integrated circuit with signal processing capability, such as a CPU. The session management network element or the diversion network element can be implemented by one or more integrated circuits configured to implement the above method. For example: one or more ASICs, or one or more microprocessors DSPs, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. Alternatively, the above implementations can be combined.

[0283] Specifically, Figure 5 The functions / implementation processes of the receiving unit 510, the sending unit 520 and the processing unit 530 in the embodiment can be realized by Figure 7 The processor 710 in the communication device 700 shown calls the computer executable instructions stored in the memory 720 to implement. Or, Figure 5 The function / implementation process of the processing unit 530 in Figure 7 The processor 710 in the communication device 700 shown calls the computer execution instructions stored in the memory 720 to implement, Figure 5 The functions / implementation processes of the receiving unit 510 and the sending unit 520 in the embodiment can be Figure 7 The interface 730 in the communication device 700 shown in FIG. 7 is implemented.

[0284] Specifically, Figure 6 The functions / implementation processes of the transceiver unit 610 and the processing unit 620 in the embodiment can be realized by Figure 7 The processor 710 in the communication device 700 shown calls the computer executable instructions stored in the memory 720 to implement. Or, Figure 6 The function / implementation process of the processing unit 620 in Figure 7 The processor 710 in the communication device 700 shown calls the computer execution instructions stored in the memory 720 to implement, Figure 6 The function / implementation process of the transceiver unit 610 can be Figure 7 The interface 730 in the communication device 700 shown in FIG. 7 is implemented.

[0285] Those of ordinary skill in the art will appreciate that the various digital numbers such as the first and second involved in this application are only for the convenience of description, and are not used to limit the scope of the embodiments of this application, and also represent the order of precedence. "And / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one" refers to one or more. At least two refers to two or more. "At least one", "any one" or similar expressions refer to any combination of these items, including any combination of single items (individuals) or plural items (individuals). For example, at least one item (individuals, kinds) of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple. "Multiple" refers to two or more, and other quantifiers are similar.

[0286] It should be understood that in various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0287] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0288] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.

[0289] The various illustrative logic units and circuits described in the embodiments of the present application can be implemented or operated by a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or the design of any combination of the above functions. The general-purpose processor can be a microprocessor, and optionally, the general-purpose processor can also be any traditional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration to implement.

[0290] The steps of the method or algorithm described in the embodiments of the present application can be directly embedded in the software unit executed by the hardware, processor, or a combination of the two. The software unit can be stored in a random access memory (Random Access Memory, RAM), flash memory, read-only memory (Read-Only Memory, ROM), EPROM memory, EEPROM memory, register, hard disk, removable disk, CD-ROM or other storage media of any form in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Optionally, the storage medium can also be integrated into the processor. The processor and the storage medium can be arranged in an ASIC.

[0291] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0292] In one or more exemplary designs, the above functions described in this application can be implemented in hardware, software, firmware, or any combination of the three. If implemented in software, these functions can be stored on a computer-readable medium, or transmitted in the form of one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media that facilitate the transfer of computer programs from one place to another. The storage medium can be any available medium that can be accessed by any general or special computer. For example, such computer-readable media can include but are not limited to RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store program codes in the form of instructions or data structures and other forms that can be read by general or special computers, or general or special processors. In addition, any connection can be appropriately defined as a computer-readable medium, for example, if the software is transmitted from a website site, server or other remote resource through a coaxial cable, fiber optic computer, twisted pair, digital subscriber line (DSL) or wirelessly, such as infrared, wireless and microwave, it is also included in the defined computer-readable medium. The disk and disc include compact disk, laser disk, optical disk, digital versatile disc (DVD), floppy disk and blue-ray disc. Disks usually copy data magnetically, while discs usually copy data optically with lasers. The above combinations can also be included in computer readable media.

[0293] Those skilled in the art should be aware that in one or more of the above examples, the functions described in this application can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any media that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that a general or special-purpose computer can access.

[0294] The specific implementation methods described above further describe the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation methods of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the present application should be included in the protection scope of the present application. The above description of the specification of the present application can make any technical field in the art use or implement the content of the present application. Any modification based on the disclosed content should be considered obvious in the art. The basic principles described in the present application can be applied to other variations without departing from the inventive essence and scope of the present application. Therefore, the content disclosed in the present application is not limited to the described embodiments and designs, but can also be extended to the maximum scope consistent with the principles of the present application and the disclosed new features.

[0295] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, a person skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for resolving a domain name system DNS request, characterized in that: include: The offloading network element receives a DNS request from a terminal device, the DNS request includes an application identifier, and the DNS request is used to request an Internet Protocol IP address of an application server corresponding to the application identifier; The offload network element determines at least one service network according to the first rule and configuration information of at least one local network, wherein the service network is deployed with a DNS server, and the configuration information of the local network includes capability information of the local network, wherein the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server, and is also used to indicate whether the local DNS server supports recursive DNS resolution when the local network is deployed with a local DNS server; the first rule is a determination rule of the service network; The offloading network element sends the DNS request to a protocol data unit anchor point PSA corresponding to the at least one service network; The offloading network element receives response information corresponding to the DNS request, where the response information includes an IP address of an application server corresponding to the application identifier; The offloading network element sends the IP address of the first application server to the terminal device, and the IP address of the application server received by the offloading network element includes the IP address of the first application server; The first rule includes at least one of the following rules: If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, select a local network from them and send the DNS request to the selected local network; If only one of the at least one local networks has a local DNS server deployed that supports recursive DNS resolution, sending the DNS request to the local network; If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, sending the DNS request to the multiple local networks; If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, select a local network from them and send the DNS request to the local network; If only one of the at least one local network has a local DNS server deployed that does not support recursive DNS resolution, the DNS request is sent to the local network; or, If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, the DNS request is sent to the multiple local networks.

2. The method according to claim 1, characterized in that The first rule is preconfigured on the diversion network element; or, The offloading network element receives the first rule from the session management network element.

3. The method according to claim 1, characterized in that The configuration information of the at least one local network is pre-configured on the diversion network element; or, The offload network element receives configuration information of the at least one local network from the session management network element.

4. The method according to any one of claims 1 to 3, characterized in that: The first rule is determined based on at least one of the deployment of a local DNS server of the local network, the resolution capability of the local DNS server, the application servers included in the local network, and the location of the local network.

5. The method according to any one of claims 1 to 3, characterized in that: The first rule also includes at least one of the following rules: If the at least one local network does not deploy a local DNS server, sending the DNS request to the central network; Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network; or, The DNS request is sent to one or more local networks in the at least one local network where a local DNS server is deployed.

6. The method according to any one of claims 1 to 3, characterized in that: The configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used by the diversion network element to select a local network closest to the terminal device from the at least one local network.

7. The method according to any one of claims 1 to 3, characterized in that: The IP address of the application server received by the diversion network element includes multiple IP addresses, and the first application server is an application server that meets the distance requirement from the terminal device among the application servers corresponding to the multiple IP addresses.

8. A method for resolving a domain name system DNS request, characterized in that: include: The offloading network element receives a DNS request from a terminal device, the DNS request includes an application identifier, and the DNS request is used to request an Internet Protocol IP address of an application server corresponding to the application identifier; The offloading network element determines at least one service network according to the first rule and configuration information of at least one local network, wherein the service network is deployed with a DNS server, and the configuration information of the local network includes capability information of the local network, wherein the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server, and is also used to indicate information of an application server deployed in the local network, and the first rule is a determination rule of the service network; The offloading network element sends the DNS request to a protocol data unit anchor point PSA corresponding to the at least one service network; The offloading network element receives response information corresponding to the DNS request, where the response information includes an IP address of an application server corresponding to the application identifier; The offloading network element sends the IP address of the first application server to the terminal device, and the IP address of the application server received by the offloading network element includes the IP address of the first application server; The first rule includes at least one of the following rules: If there are multiple local networks in the at least one local network that are deployed with the application server corresponding to the application identifier, and the multiple local networks are deployed with local DNS servers, select a local network from the at least one local network and send the DNS request to the local network; If there is only one local network in the at least one local network where the application server corresponding to the application identifier is deployed, and the local network is deployed with a local DNS server, sending the DNS request to the local network; If one or more local networks in the at least one local network have deployed an application server corresponding to the application identifier, and none of the one or more local networks have deployed a local DNS server, sending the DNS request to the central network; or, If the at least one local network does not deploy the application server corresponding to the application identifier, the DNS request is sent to the central network.

9. The method according to claim 8, characterized in that The first rule is preconfigured on the diversion network element; or, The offloading network element receives the first rule from the session management network element.

10. The method according to claim 8, characterized in that The configuration information of the at least one local network is pre-configured on the diversion network element; or, The offload network element receives configuration information of the at least one local network from the session management network element.

11. The method according to any one of claims 8 to 10, characterized in that: The first rule is determined based on at least one of the deployment of a local DNS server of the local network, the resolution capability of the local DNS server, the application servers included in the local network, and the location of the local network.

12. The method according to any one of claims 8 to 10, characterized in that: The first rule also includes at least one of the following rules: If the at least one local network does not deploy a local DNS server, sending the DNS request to the central network; Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network; or, The DNS request is sent to one or more local networks in the at least one local network where a local DNS server is deployed.

13. The method according to any one of claims 8 to 10, characterized in that: The configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used by the diversion network element to select a local network closest to the terminal device from the at least one local network.

14. The method according to any one of claims 8 to 10, characterized in that: The IP address of the application server received by the diversion network element includes multiple IP addresses, and the first application server is an application server that meets the distance requirement from the terminal device among the application servers corresponding to the multiple IP addresses.

15. A communication device, characterized in that: include: A receiving unit, configured to receive a DNS request from a terminal device, the DNS request including an application identifier, the DNS request being used to request an Internet Protocol IP address of an application server corresponding to the application identifier; and receive response information corresponding to the DNS request, the response information including the IP address of the application server corresponding to the application identifier; a processing unit, configured to determine at least one service network according to a first rule and configuration information of at least one local network, wherein the service network is deployed with a DNS server, the configuration information of the local network includes capability information of the local network, the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server, and is also used to indicate whether the local DNS server supports recursive DNS resolution when the local network is deployed with a local DNS server; the first rule is a determination rule of the service network; A sending unit, configured to send the DNS request to a protocol data unit anchor point PSA corresponding to the at least one service network; Sending the IP address of the first application server to the terminal device, wherein the IP address of the application server received by the communication device includes the IP address of the first application server; The first rule includes at least one of the following rules: If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, select a local network from them and send the DNS request to the selected local network; If only one of the at least one local networks has a local DNS server deployed that supports recursive DNS resolution, sending the DNS request to the local network; If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, sending the DNS request to the multiple local networks; If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, select a local network from them and send the DNS request to the local network; If only one of the at least one local network has a local DNS server deployed that does not support recursive DNS resolution, the DNS request is sent to the local network; or, If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, the DNS request is sent to the multiple local networks.

16. The device according to claim 15, characterized in that The first rule is preconfigured on the communication device; or, The receiving unit is further configured to receive the first rule from a session management network element.

17. The device according to claim 15, characterized in that The configuration information of the at least one local network is pre-configured on the communication device; or, The receiving unit is further configured to receive configuration information of the at least one local network from a session management network element.

18. The device according to any one of claims 15 to 17, characterized in that: The first rule is determined based on at least one of the deployment of a local DNS server of the local network, the resolution capability of the local DNS server, the application servers included in the local network, and the location of the local network.

19. The device according to any one of claims 15 to 17, characterized in that: The first rule also includes at least one of the following rules: If the at least one local network does not deploy a local DNS server, sending the DNS request to the central network; Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network; or, The DNS request is sent to one or more local networks in the at least one local network where a local DNS server is deployed.

20. The device according to any one of claims 15 to 17, characterized in that: The configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used to select a local network closest to the terminal device from the at least one local network.

21. The device according to any one of claims 15 to 17, characterized in that: The IP address of the application server received by the receiving unit includes multiple IP addresses, and the first application server is an application server that meets the distance requirement with the terminal device among the application servers corresponding to the multiple IP addresses.

22. A communication device, characterized in that: include: A receiving unit, configured to receive a DNS request from a terminal device, the DNS request including an application identifier, the DNS request being used to request an Internet Protocol IP address of an application server corresponding to the application identifier; and receive response information corresponding to the DNS request, the response information including the IP address of the application server corresponding to the application identifier; a processing unit, configured to determine at least one service network according to a first rule and configuration information of at least one local network, wherein the service network is deployed with a DNS server, the configuration information of the local network includes capability information of the local network, the capability information of the local network is used to indicate whether the local network is deployed with a local DNS server, and is also used to indicate information of an application server deployed in the local network; The first rule is a rule for determining a service network; A sending unit, configured to send the DNS request to a protocol data unit anchor point PSA corresponding to the at least one service network; Sending the IP address of the first application server to the terminal device, wherein the IP address of the application server received by the communication device includes the IP address of the first application server; The first rule includes at least one of the following rules: If there are multiple local networks in the at least one local network that are deployed with the application server corresponding to the application identifier, and the multiple local networks are deployed with local DNS servers, select a local network from the at least one local network and send the DNS request to the local network; If there is only one local network in the at least one local network where the application server corresponding to the application identifier is deployed, and the local network is deployed with a local DNS server, sending the DNS request to the local network; If one or more local networks in the at least one local network have deployed an application server corresponding to the application identifier, and none of the one or more local networks have deployed a local DNS server, sending the DNS request to the central network; or, If the at least one local network does not deploy the application server corresponding to the application identifier, the DNS request is sent to the central network.

23. The device according to claim 22, characterized in that The first rule is preconfigured on the communication device; or, The receiving unit is further configured to receive the first rule from a session management network element.

24. The device according to claim 22, characterized in that The configuration information of the at least one local network is pre-configured on the communication device; or, The receiving unit is further configured to receive configuration information of the at least one local network from a session management network element.

25. The device according to any one of claims 22 to 24, characterized in that: The first rule is determined based on at least one of the deployment of a local DNS server of the local network, the resolution capability of the local DNS server, the application servers included in the local network, and the location of the local network.

26. The device according to any one of claims 22 to 24, characterized in that: The first rule also includes at least one of the following rules: If the at least one local network does not deploy a local DNS server, sending the DNS request to the central network; Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network; or, The DNS request is sent to one or more local networks in the at least one local network where a local DNS server is deployed.

27. The device according to any one of claims 22 to 24, characterized in that: The configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used to select a local network closest to the terminal device from the at least one local network.

28. The device according to any one of claims 22 to 24, characterized in that: The IP address of the application server received by the receiving unit includes multiple IP addresses, and the first application server is an application server that meets the distance requirement with the terminal device among the application servers corresponding to the multiple IP addresses.

29. A communication system, characterized in that: include: A session management network element, configured to determine a first rule according to at least one of a local DNS server deployment of a local network, a resolution capability of a local DNS server, an application server included in the local network, and a location of the local network; determine a local network that a terminal device can access; and send configuration information of the local network that the terminal device can access and the first rule to a diversion network element, wherein the configuration information of the local network includes capability information of the local network, and the capability information of the local network is used to indicate whether a local DNS server is deployed in the local network, and is also used to indicate whether the local DNS server supports recursive DNS resolution when a local DNS server is deployed in the local network; A distribution network element, configured to receive the configuration information of the local network and the first rule from the session management network element; The first rule includes at least one of the following rules: If there are multiple local networks in at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, select a local network from them and send the DNS request to the local network; If only one of the at least one local networks has a local DNS server deployed that supports recursive DNS resolution, sending the DNS request to the local network; If there are multiple local networks in the at least one local network that are deployed with local DNS servers supporting recursive DNS resolution, sending the DNS request to the multiple local networks; If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, select a local network from them and send the DNS request to the local network; If only one of the at least one local network has a local DNS server deployed that does not support recursive DNS resolution, the DNS request is sent to the local network; or, If there are multiple local networks in the at least one local network that are deployed with local DNS servers that do not support recursive DNS resolution, the DNS request is sent to the multiple local networks.

30. The system of claim 29, wherein: The traffic distribution network element is further used for: Receiving a DNS request from the terminal device, the DNS request including an application identifier, the DNS request being used to request an Internet Protocol IP address of an application server corresponding to the application identifier; Determine at least one service network according to the first rule and the configuration information of the local network, where a DNS server is deployed; Sending the DNS request to a protocol data unit anchor point PSA corresponding to the at least one service network; Receiving response information corresponding to the DNS request, the response information including the IP address of the application server corresponding to the application identifier; The IP address of the first application server is sent to the terminal device, and the IP address of the application server received by the diversion network element includes the IP address of the first application server.

31. The system of claim 29, wherein: The first rule also includes at least one of the following rules: If the at least one local network does not deploy a local DNS server, sending the DNS request to the central network; Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network; or, The DNS request is sent to one or more local networks in the at least one local network where a local DNS server is deployed.

32. The system according to any one of claims 29 to 31, characterized in that: The configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used by the diversion network element to select a local network closest to the terminal device from the at least one local network.

33. The system according to any one of claims 29 to 31, characterized in that: The IP address of the application server received by the diversion network element includes multiple IP addresses, and the first application server is an application server that meets the distance requirement from the terminal device among the application servers corresponding to the multiple IP addresses.

34. A communication system, characterized in that: include: A session management network element, configured to determine a first rule according to at least one of a local DNS server deployment of a local network, a resolution capability of a local DNS server, an application server included in the local network, and a location of the local network; determine a local network that a terminal device can access; and send configuration information of a local network that the terminal device can access and the first rule to a diversion network element, wherein the configuration information of the local network includes capability information of the local network, and the capability information of the local network is used to indicate whether a local DNS server is deployed in the local network, and is also used to indicate information of an application server deployed in the local network; A distribution network element, configured to receive the configuration information of the local network and the first rule from the session management network element; The first rule also includes at least one of the following rules: If there are multiple local networks in the at least one local network that are deployed with application servers corresponding to the application identifier, and the multiple local networks are deployed with local DNS servers, select a local network from the at least one local network and send the DNS request to the local network; If there is only one local network in the at least one local network where the application server corresponding to the application identifier is deployed, and the local network is deployed with a local DNS server, sending the DNS request to the local network; If one or more local networks in the at least one local network have deployed an application server corresponding to the application identifier, and none of the one or more local networks have deployed a local DNS server, sending the DNS request to the central network; or, If the at least one local network does not deploy the application server corresponding to the application identifier, the DNS request is sent to the central network.

35. The system of claim 34, wherein: The traffic distribution network element is further used for: Receiving a DNS request from the terminal device, the DNS request including an application identifier, the DNS request being used to request an Internet Protocol IP address of an application server corresponding to the application identifier; Determine at least one service network according to the first rule and the configuration information of the local network, where a DNS server is deployed; Sending the DNS request to a protocol data unit anchor point PSA corresponding to the at least one service network; Receiving response information corresponding to the DNS request, the response information including the IP address of the application server corresponding to the application identifier; The IP address of the first application server is sent to the terminal device, and the IP address of the application server received by the diversion network element includes the IP address of the first application server.

36. The system of claim 34, wherein: The first rule also includes at least one of the following rules: If the at least one local network does not deploy a local DNS server, sending the DNS request to the central network; Sending the DNS request to a local network in which a local DNS server is deployed in the at least one local network, and to a central network; or, The DNS request is sent to one or more local networks in the at least one local network where a local DNS server is deployed.

37. The system according to any one of claims 34 to 36, characterized in that: The configuration information of the local network also includes location information or service area information of the local network, and the location information or service area information is used by the diversion network element to select a local network closest to the terminal device from the at least one local network.

38. The system according to any one of claims 34 to 36, characterized in that: The IP address of the application server received by the diversion network element includes multiple IP addresses, and the first application server is an application server that meets the distance requirement from the terminal device among the application servers corresponding to the multiple IP addresses.

39. A computer-readable storage medium, characterized in that: The method comprises a computer program which, when executed on a computer, causes the computer to execute the method according to any one of claims 1 to 14.

40. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is run on a computer, the computer is caused to execute the method according to any one of claims 1 to 14.

Images