WO2021081712A1

WO2021081712A1 - Dns query method and apparatus

Info

Publication number: WO2021081712A1
Application number: PCT/CN2019/113739
Authority: WO
Inventors: 李永翠; 吴义壮; 倪慧
Original assignee: 华为技术有限公司
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2021-05-06

Abstract

Provided are a DNS query method and apparatus. The method comprises: when a terminal device is moved and the time to live of a DNS resource record corresponding to a domain name of an application of the terminal device has not expired, if a first condition is satisfied, sending a first message to a DNS server, wherein the first message is used for querying an IP address corresponding to the domain name; and receiving a second message sent by the DNS server, wherein the second message comprises the IP address corresponding to the domain name, and an application server indicated by the IP address corresponds to the position, after movement, of the terminal device. In the solution, after a terminal device is moved, when the time to live of a DNS resource record has not expired, as long as a first condition is satisfied, a query for an IP address corresponding to a domain name is initiated to a DNS server, and an application server indicated by the IP address corresponds to the position, after movement, of the terminal device, thereby realizing nearby access to a service.

Description

A DNS query method and device

Technical field

This application relates to the field of mobile communication technology, and in particular to a DNS query method and device.

Background technique

As the number of mobile phone users continues to grow, the business functions supported by various mobile phone terminals continue to increase. For example, functions such as mobile securities, mobile browsing, and file download have gradually become mainstream applications for mobile terminals, especially smart phones. In the process of surfing the Internet, the mobile phone needs to query the Internet Protocol (IP) address of the application server corresponding to the domain name in order to send data packets. This operation needs to be completed by querying the Domain Name System (DNS) server.

The domain name system is a distributed host information database that provides mapping and conversion between domain names and IP addresses, and can resolve domain names to corresponding IP addresses through DNS servers. The terminal device can realize the access to the domain name through the domain name resolution service provided by the DNS server.

At present, the process of domain name access is as follows: Take the terminal device accessing domain name A as an example. When the terminal device accesses the domain name A, query whether the IP address corresponding to the domain name A exists in the DNS resource record of the terminal device. If it exists, the terminal device You can directly obtain the IP address, and then access the domain name A through the IP address; if it does not exist, the terminal device can send a domain name resolution request to the DNS server, the domain name resolution request carries the domain name A, and the DNS server returns the corresponding domain name A The terminal device can access the domain name A through the IP address.

After obtaining the IP address corresponding to the domain name, the terminal device generates and caches a DNS resource record. The DNS resource record is used to indicate the correspondence between the domain name and the IP address. In addition, the terminal device maintains a corresponding time to live (TTL) for each cached DNS resource record.

TTL indicates the storage or cache time of the DNS resource record corresponding to the IP address in the cache of the terminal device. A time of 0 means that it can only be transmitted but cannot be cached. If in the TTL of the DNS resource record, when the terminal device needs to access the same domain name in the DNS resource record again, the terminal device can directly obtain the IP address corresponding to the domain name based on the DNS resource record; if the TTL of the DNS resource record is exceeded, When the terminal device needs to access the domain name again, the terminal device needs to resolve the IP address corresponding to the domain name through the DNS server through the above process.

In the 5th generation (5G) communication, by bringing services closer to users, it is possible to provide users with a more reliable and ultimate service experience. In other words, the business corresponding to the domain name may be deployed in a distributed manner. When a terminal device accesses the service at a different location, it can access the distributed application server to achieve nearby access. However, for mobile terminal devices, when the terminal device obtains the DNS resource record corresponding to a certain domain name before the move, if the TTL of the DNS resource record is still valid after the terminal device moves, it will be unable to access at the current location. The service of the application server corresponding to the domain name.

Summary of the invention

This application provides a DNS query method and device, which are used to enable terminal equipment to access services in the application server corresponding to the IP address nearby.

In the first aspect, this application provides a DNS query method, including: in the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, Sending a first message to the DNS server, the first message being used to query the IP address corresponding to the domain name; receiving a second message sent by the DNS server, the second message including the IP address corresponding to the domain name, The application server indicated by the IP address corresponds to the moved position of the terminal device.

In this solution, after the terminal device is moved, if the retention time of the DNS resource record has not expired, as long as the first condition is met, the terminal device will initiate a query to the DNS server for the IP address corresponding to the domain name, and the IP address indicates The application server corresponds to the location of the terminal device after it has moved. Therefore, what the terminal device accesses is the service of the application server corresponding to the position of the terminal device after it is moved, and the nearby access of the service is realized.

In a second aspect, this application provides a DNS query method, which includes: in the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, Sending a first message to the DNS server, the first message being used to query the Internet Protocol IP address corresponding to the domain name; receiving a second message sent by the DNS server, the second message including the indication information, the The indication information is used to indicate that the IP address corresponding to the domain name has not changed, and the application server indicated by the IP address corresponds to the position of the terminal device after it has moved.

In this solution, after the terminal device is moved, if the retention time of the DNS resource record has not expired, as long as the first condition is met, the terminal device will initiate a query to the DNS server for the IP address corresponding to the domain name, when the IP address before and after the query When it does not change, the DNS server sends instruction information to the terminal device to indicate that the IP address corresponding to the domain name has not changed, and the application server indicated by the IP address corresponds to the position of the terminal device after it has moved. Therefore, what the terminal device accesses is the service of the application server corresponding to the position of the terminal device after it is moved, and the nearby access of the service is realized.

Based on the above-mentioned first aspect or second aspect:

In a possible implementation method, the first condition includes any one of the following: there are multiple application servers corresponding to the domain name; or, there are multiple application servers corresponding to the domain name, and the terminal device is removed The intersection area of the terminal device is the intersection area between the registration area and the domain name range of the domain name; or, the retention time of the DNS resource record is less than a preset threshold.

In a possible implementation method, the movement of the terminal device includes: inter-cell movement of the terminal device; or, the movement of the terminal device causes the data network access identifier DNAI corresponding to the terminal device to change; or , The terminal device moves between tracking areas; or, the terminal device moves out of the intersection area between the registration area of the terminal device and the domain name range of the domain name.

In a third aspect, this application provides a DNS query method, including: obtaining domain name information of an application of a terminal device, where the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name; and sending the domain name to the terminal device Information, the domain name information is used for the terminal device to determine whether to send a first message, and the first message is used for querying the IP address corresponding to the domain name.

In this solution, domain name information is sent to the terminal device, so that after the terminal device is moved, if the retention time of the DNS resource record has not expired, the domain name information can be used to determine whether to initiate a query to the DNS server for the IP address corresponding to the domain name, which is helpful The terminal equipment realizes the nearby visit of the business.

In a possible implementation method, determine the intersection area between the registration area of the terminal device and the domain name range of the domain name; send the intersection area to the terminal device, and the intersection area is used for the terminal The device determines whether to send the first message.

In a possible implementation method, obtaining the domain name information of the application includes: receiving the domain name information from a centralized control network element; or, receiving the service description information and the service description information corresponding to the domain name from the centralized control network element The corresponding service location determines the domain name information according to the service description information and the service location.

In a possible implementation method, the domain name information includes the domain name and indication information, and the indication information is used to indicate whether there are multiple application servers corresponding to the domain name.

In a fourth aspect, this application provides a DNS query method, including: receiving a DNS query request from a terminal device, where the DNS query request includes a domain name of an application of the terminal device; and setting a retention time according to the domain name information of the domain name, The retention time is the retention time of the DNS resource record corresponding to the domain name; the IP address corresponding to the domain name and the retention time are sent to the terminal device, and the retention time is used by the terminal device to determine whether to send the first A message, the first message is used to query the IP address corresponding to the domain name.

In this solution, the retention time is set according to the domain name information, and the retention time is sent to the terminal device, so that after the terminal device moves, if the retention time of the DNS resource record has not expired, it can be judged whether to initiate a query to the DNS server according to the retention time The IP address corresponding to the domain name helps the terminal device to realize the nearby access of the business.

In a possible implementation method, setting the retention time according to the domain name information of the domain name includes: if the domain name information indicates that there are multiple application servers corresponding to the domain name, setting the retention time to be less than a preset threshold; Alternatively, if the domain name information indicates that there is one application server corresponding to the domain name, the retention time is set to be greater than a preset threshold.

In a fifth aspect, the present application provides a communication device, which may be a terminal device or a chip for the terminal device. The device has the function of realizing the foregoing first aspect, or second aspect, or each embodiment of the first aspect, or each embodiment of the second aspect. This function can be realized by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions.

In a sixth aspect, this application provides a communication device, which may be a policy control network element or a DNS server, or a chip used for a policy control network element or a DNS server. The device has the function of realizing the foregoing third aspect or the embodiments of the third aspect. This function can be realized by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions.

In a seventh aspect, the present application provides a communication device, which may be a DNS server or a chip used for the DNS server. The device has the function of realizing the foregoing fourth aspect or the embodiments of the fourth aspect. This function can be realized by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions.

In an eighth aspect, the present application provides a communication device, including: 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 to enable the The device executes the methods described in the above aspects. The device may be a terminal device, or a chip used for a terminal device, or a policy control network element, or a chip used for a policy control network element, or a DNS server, or a chip used for a DNS server.

In a ninth aspect, the present application provides a communication device, including: including units or means for performing each step of the above-mentioned aspects. The device can be a policy control network element, or a terminal device, or a DNS server.

In a tenth aspect, the present application provides a communication device including a processor and an interface circuit, and the processor is configured to implement the methods described in the foregoing aspects through the interface circuit. The processor includes one or more. The device may be a chip used for session management network elements, terminal equipment, or DNS server.

In an eleventh aspect, the present application provides a communication device, including a processor, configured to be connected to a memory, and configured to call a program stored in the memory to execute the methods described in the foregoing aspects. The memory can be located inside the device or outside the device. And the processor includes one or more. The device may be a terminal device, or a chip used for a terminal device, or a policy control network element, or a chip used for a policy control network element, or a DNS server, or a chip used for a DNS server.

In a twelfth aspect, this application also provides a computer-readable storage medium having instructions stored in the computer-readable storage medium, which when run on a computer, cause a processor to execute the methods described in the above aspects.

In the thirteenth aspect, this application also provides a computer program product including instructions, which when run on a computer, causes the computer to execute the methods described in the above aspects.

In a fourteenth aspect, this application also provides a chip system, including a processor, configured to execute the methods described in the foregoing aspects.

In a fifteenth aspect, this application provides a communication system including a policy control network element and a mobility management network element. Optionally, the system also includes terminal equipment.

The policy control network element is used to obtain domain name information of the application of the terminal device, the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name; and the domain name information is sent to the mobility management network element;

The mobility management network element is configured to send the domain name information to the terminal device, where the domain name information is used by the terminal device to determine whether to send a first message, and the first message is used to query the corresponding domain name Internet Protocol IP address.

In a possible implementation method, the policy control network element is also used to determine the intersection area between the registration area of the terminal device and the domain name range of the domain name; The intersection area; the mobility management network element is also used to send the intersection area to the terminal device, and the intersection area is used by the terminal device to determine whether to send the first message.

In a possible implementation method, the policy control network element is used to obtain the domain name information of the terminal device application, which specifically includes: used to receive the domain name information from the centralized control network element; or, used to receive the domain name information from the centralized control The network element receives the service description information corresponding to the domain name and the service location corresponding to the service description information, and determines the domain name information according to the service description information and the service location.

In a possible implementation method, the terminal device is configured to: when the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application does not expire, if it is satisfied The first condition is to send a first message to the DNS server, where the first message is used to query the IP address corresponding to the domain name; and to receive a second message sent by the DNS server, the second message includes information corresponding to the domain name An IP address, where the application server indicated by the IP address corresponds to the position of the terminal device after it has moved.

In a possible implementation method, the terminal device is configured to: when the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application does not expire, if it is satisfied The first condition is to send a first message to the DNS server, where the first message is used to query the IP address corresponding to the domain name; and to receive a second message sent by the DNS server, where the second message includes indication information, so The indication information is used to indicate that the IP address corresponding to the domain name has not changed, and the application server indicated by the IP address corresponds to the position of the terminal device after it has moved.

In a possible implementation method, the first condition includes any one of the following: there are multiple application servers corresponding to the domain name; or, there are multiple application servers corresponding to the domain name, and the terminal device is removed The intersection area is an intersection area between the registration area of the terminal device and the domain name range of the domain name.

In a sixteenth aspect, this application provides a communication system including a terminal device and a DNS server. The DNS server is used for a DNS query request from the terminal device, the DNS query request includes the domain name of the terminal device application; the retention time is set according to the domain name information of the domain name, and the retention time is the The retention time of the DNS resource record corresponding to the domain name; sending the Internet Protocol IP address corresponding to the domain name and the retention time to the terminal device; the terminal device is used to determine whether to send the first message according to the retention time, The first message is used to query the IP address corresponding to the domain name.

In a possible implementation method, the DNS server is configured to set the retention time according to the domain name information of the domain name, specifically including: if the domain name information indicates that there are multiple application servers corresponding to the domain name, then Set the retention time to be less than a preset threshold; or, if the domain name information indicates that there is one application server corresponding to the domain name, set the retention time to be greater than the preset threshold.

In a seventeenth aspect, this application provides a communication method, including: a policy control network element obtains domain name information of an application of a terminal device, where the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name; the policy control network Element sends the domain name information to the mobility management network element; the mobility management network element sends the domain name information to the terminal device, and the domain name information is used by the terminal device to determine whether to send the first message, the The first message is used to query the Internet Protocol IP address corresponding to the domain name.

In a possible implementation method, the policy control network element determines the intersection area between the registration area of the terminal device and the domain name range of the domain name; sends the intersection area to the mobility management network element; The mobility management network element sends the intersection area to the terminal device, where the intersection area is used by the terminal device to determine whether to send the first message.

In a possible implementation method, acquiring, by the policy control network element, the domain name information of the application of the terminal device includes: the policy control network element receives the domain name information from a centralized control network element; or, the policy control network The element receives the service description information corresponding to the domain name and the service location corresponding to the service description information from the centralized control network element, and determines the domain name information according to the service description information and the service location.

In a possible implementation method, when the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application does not expire, if the first condition is met, the terminal device Send a first message to the DNS server, the first message is used to query the IP address corresponding to the domain name; the terminal device receives the second message sent by the DNS server, the second message includes the corresponding domain name An IP address, where the application server indicated by the IP address corresponds to the position of the terminal device after it has moved.

In a possible implementation method, when the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application does not expire, if the first condition is met, the terminal device Send a first message to the DNS server, the first message is used to query the IP address corresponding to the domain name; the terminal device receives a second message sent by the DNS server, the second message includes indication information, so The indication information is used to indicate that the IP address corresponding to the domain name has not changed, and the application server indicated by the IP address corresponds to the position of the terminal device after it has moved.

Description of the drawings

Figure 1 is a schematic diagram of a possible network architecture applicable to this application;

Figure 2 is a schematic diagram of another possible network architecture to which this application applies;

Figure 3 is a schematic diagram of an MEC scenario provided by this application;

FIG. 4A is a schematic flowchart of a DNS query method provided by this application;

FIG. 4B is a schematic flowchart of another DNS query method provided by this application;

Figure 5 is a schematic flow diagram of another DNS query method provided by this application;

Figure 6 is a schematic flow diagram of another DNS query method provided by this application;

FIG. 7 is a schematic diagram of a communication device provided by this application;

FIG. 8 is a schematic diagram of another communication device provided by this application;

FIG. 9 is a schematic diagram of another communication device provided by this application;

FIG. 10 is a schematic diagram of a terminal device provided by this application;

FIG. 11 is a schematic diagram of a policy control network element provided by this application;

Figure 12 is a schematic diagram of a DNS server provided by this application;

FIG. 13 is a schematic diagram of a communication system provided by this application;

FIG. 14 is a schematic diagram of another communication system provided by this application.

Detailed ways

In order to make the purpose, technical solutions, and advantages of the application more clear, the 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. Among them, in the description of the present application, unless otherwise specified, "multiple" means two or more.

As shown in Figure 1, it is a schematic diagram of a 5G network architecture based on a service-oriented architecture. The 5G network architecture shown in FIG. 1 may include three parts, namely a terminal equipment part, a data network (DN), and an operator network part. The functions of some of the network elements are briefly introduced below.

Among them, the operator network may include one or more of the following network elements: network exposure function (NEF) network elements, network storage function (Network Repository Function, NRF) network elements, policy control function (policy control function) , PCF) network element, unified data management (UDM) network element, network data analysis function network element (Network Data Analytics Function, NWDAF) network element, application function (AF) network element, access and Mobility management function (access and mobility management function, AMF) network elements, session management function (session management function, SMF) network elements, radio access network (RAN), unified data repository (Unified Data Repository, UDR) (not shown in the figure) and user plane function (UPF) network elements. In the above-mentioned operator network, parts other than the radio access network part may be referred to as the core network part.

Terminal device (terminal device), also called user equipment (user equipment, UE), is a device with wireless transceiver function, which can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; it can also be deployed on water On board (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons, and satellites, etc.). The terminal device may be a mobile phone (mobile phone), a tablet computer (pad), a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, an industrial control (industrial control) Wireless terminals in ), wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grid, and wireless terminals in transportation safety , Wireless terminals in smart cities, wireless terminals in smart homes, etc. For ease of description, this application will use UE instead of the terminal device for description in the following.

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

RAN is a sub-network of an operator's network, and an implementation system between service nodes and terminal equipment in the operator's network. To access the operator's network, the terminal device first passes through the RAN, and then can be connected to the service node of the operator's network through the RAN. The RAN device in this application is a device that provides wireless communication functions for terminal devices, and the RAN device is also called an access network device. The RAN equipment in this application includes but is not limited to: next-generation base stations (gnodeB, gNB), evolved node B (evolved node B, eNB), radio network controller (RNC), node B in 5G (node B, NB), base station controller (BSC), 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.

AMF network element, mobility management function, responsible for user mobility management, including mobility status management, assigning user temporary identities, authenticating and authorizing users.

SMF network element, session management function, responsible for UPF selection, UPF reselection, IP address allocation, responsible for bearer establishment, modification and release, and QoS control.

UPF network elements support all or part of the following functions: Interconnect protocol data unit (PDU) sessions with data networks; packet routing and forwarding (for example, support for Uplink classifier and forwarding of traffic to the data network, support for Branching point to support multi-homed PDU session); data packet inspection.

A DN is a network located outside the operator's network. The operator's network can access multiple DNs, and multiple services can be deployed on the DN, which can provide data and/or voice services for terminal devices. For example, DN is a private network of a smart factory. The sensors installed in the workshop of the smart factory can be terminal devices. A control server for the sensors is deployed in the DN, and the control server can provide services for the sensors. The sensor 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, the DN is the internal office network of a company. The mobile phones or computers of the employees of the company can be terminal devices, and the mobile phones or computers of the employees can access the information and data resources on the internal office network of the company.

The UDM network element is responsible for managing the contracted data, and when the contracted data is modified, it is responsible for notifying the corresponding network element.

UDR is used to store and retrieve contract data, policy data and public structure data, etc.; for UDM, PCF and NEF to obtain relevant data. UDR must be able to have different data access authentication mechanisms for different types of data such as contract data and policy data to ensure the security of data access; UDR must be able to return and carry appropriate data for illegal servicing operations or data access requests The failure response for the reason value.

NEF network elements are mainly used to support the opening of capabilities and events.

The AF network element provides certain application layer services to the UE. When the AF provides services to the UE, it has requirements for QoS policies and charging policies (Charging) and needs to notify the network. At the same time, AF also needs application-related information fed back from the core network.

PCF network elements include policy control decision-making and flow-based charging control functions, including user subscription data management functions, policy control functions, charging policy control functions, QoS control, etc.

The NRF network element can be used to provide the network element discovery function, and provide the network element information corresponding to the network element type based on the request of other network elements. NRF also provides network element management services, such as network element registration, update, de-registration, and network element status subscription and push.

The NWDAF network element is used to provide the big data analysis information of the contracted terminal according to the request of the policy module PCF, and help the PCF optimize the strategy control; it can provide the big data analysis information according to the slice dimension.

In Figure 1, Nnef, Nnrf, Npcf, Nudm, Nnwdaf, Naf, Namf, Nsmf, N1, N2, N3, N4, and N6 are interface serial numbers. The meanings of these interface serial numbers can be referred to the meanings defined in the 3rd generation partnership project (3rd generation partnership project, 3GPP) standard protocol, which is not limited here.

As shown in Fig. 2, it is a schematic diagram of a 5G network architecture based on a point-to-point interface. For the introduction of the functions of the network elements therein, reference may be made to the introduction of the functions of the corresponding network elements in Fig. 1, which will not be repeated. The main difference between Figure 2 and Figure 1 is that the interfaces between the various network elements in Figure 2 are point-to-point interfaces rather than service-oriented interfaces. It should be noted that FIG. 2 also includes other network elements, such as NEF network elements, NRF network elements, UDR network elements, and NWDAF network elements, which are not shown in FIG. 2.

In the architecture shown in Figure 2, the interface between the UE and the AMF network element is called the N1 interface, the interface between the AMF network element and the RAN device is called the N2 interface, and the interface between the RAN device and the UPF network element It can be called N3 interface, the interface between SMF network element and UPF network element is called N4 interface, the interface between PCF network element and AF network element is called N5 interface, and the interface between UPF network element and DN is called N6 Interface, the interface between SMF network element and PCF network element is called N7 interface, the interface between AMF network element and UDM network element is called N8 interface, the interface between different UPF network elements is called N9 interface, UDM network element The interface with the SMF network element is called the N10 interface, the interface between the AMF network element and the SMF network element is called the N11 interface, the interface between different AMF network elements is called the N14 interface, and the one between the AMF network element and the PCF network element The interface between is called N15 interface.

It is understandable that the aforementioned network elements or functions may be network elements in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (for example, a cloud platform). Optionally, the foregoing network element or function may be implemented by one device, or jointly implemented by multiple devices, or may be a functional module in one device, which is not specifically limited in the embodiment of the present application.

The mobility management network element, session management network element, policy control network element, application function network element, access network device, network opening function network element, and user plane network element in this application may be those in Figure 1 or Figure 2 respectively. AMF, SMF, PCF, AF, RAN, NEF, UPF, or future communications such as the 6th generation (6G) network with the above-mentioned functions of AMF, SMF, PCF, AF, RAN, NEF, UPF Yuan, this application is not limited. For the convenience of explanation, in this application, mobility management network elements, session management network elements, policy control network elements, application function network elements, access network equipment, network open function network elements, and user plane network elements are respectively the above-mentioned AMF, SMF, and SMF. Take PCF, AF, RAN, NEF, UPF as examples for description. In addition, the terminal device is referred to as UE for short in this application.

In order to facilitate the understanding of the present invention, the background knowledge of the present invention will be introduced and explained below.

1. Mobile Edge Computing (MEC)

The rapid development of mobile communication has promoted the continuous emergence of various new services. In addition to traditional mobile broadband and the Internet of Things, mobile communication has spawned many new application areas such as Augmented Reality (AR) and Virtual Reality (Virtual Reality). , VR), Internet of Vehicles, Industrial Control, Internet of Things (IoT), etc. At the same time, higher requirements for network bandwidth, delay and other performance are also put forward, and the network load is further increased.

In order to effectively meet the high-bandwidth and low-latency requirements for the rapid development of mobile Internet and Internet of Things and reduce network load, the European Telecommunication Standard Institute (ETSI) proposed MEC technology in 2014.

Based on the 5G architecture, the MEC architecture has evolved: Compared with the central data network (central DN), the edge location closer to the end user can provide the network architecture that users need services and cloud computing functions, combining applications, content, and core The functions of network service processing and resource scheduling are deployed together at the edge of the network close to the end user, and the service is close to the user processing, as well as the collaboration of applications, content and the network to provide a reliable and extreme service experience. As shown in Figure 3, it is a schematic diagram of the MEC scene. Among them, the MEC platform is deployed at the sinking UPF (that is, the local UPF) and the DN is deployed at the remote UPF. Compared with the path for the UE to access the DN, the path for the UE to access the MEC platform is greatly shortened. Therefore, MEC technology can provide users with low-latency, high-bandwidth services.

2. Domain Name System (DNS)

The DNS query process is:

The UE starts an application (APP), initiates a session establishment process or reuses an existing session of the UE to establish a user plane connection between the UE and the UPF. During the session establishment process, the SMF sends the address of the DNS server to the UE.

For the APP (or the service), the UE determines whether there is a DNS record related to the domain name of the service locally. Among them, the DNS record contains the correspondence between the domain name and the IP address.

If the UE locally has a DNS record related to the domain name of the service, the UE determines the IP address corresponding to the domain name according to the DNS record, and uses the IP address as the destination IP of the service.

If the UE does not have a DNS record related to the domain name of the service locally, the UE initiates a DNS query process. Specifically, the UE sends a DNS query request to the DNS server, and the DNS query request carries the domain name of the service. After receiving the DNS query request, the DNS server queries the database to obtain the IP address corresponding to the domain name, and returns a DNS response message to the UE, which carries the IP address and time-to-live (TTL) corresponding to the domain name. TTL indicates the time that the DNS record can be cached. TTL is an unsigned integer of 4 bytes. TTL=0 means that the DNS record cannot be cached. Then, the UE saves the DNS record and uses the IP address in the DNS record as the destination IP of the service.

The problems to be solved by the present invention are introduced and explained below.

One or more applications are installed in the UE, and each application corresponds to one or more services. When the UE initiates the service, it initiates the service through the pre-configured domain name corresponding to the application.

Before the UE moves, it starts APP1 and initiates a session establishment process. In this process, the SMF sends the DNS server address to the UE. The UE initiates a DNS query process to the DNS server to query the address corresponding to the domain name of APP1. Specifically, the UE sends a DNS query request to the DNS server, carrying the domain name; the DNS server returns a DNS response message, carrying the TTL and IP address corresponding to the domain name. Then, the UE saves the correspondence between the domain name, TTL, and IP address.

By analogy, the UE starts APP2, assuming that APP2 reuses the current session; the UE initiates a DNS query to the DNS server to query the address corresponding to the domain name of APP2. The UE saves the corresponding relationship between the domain name, TTL, and IP address.

By analogy, the UE starts APP3, assuming that APP3 reuses the current session; the UE initiates a DNS query to the DNS server to query the address corresponding to the domain name of APP3. The UE saves the corresponding relationship between the domain name, TTL, and IP address.

So far, the DNS records (correspondence between domain name, TTL, and IP address) saved on the UE are shown in Table 1 below.

Table 1

域名domain name	IP地址IP address	TTLTTL
域名1Domain name 1	IP1IP1	TTL1TTL1
域名2Domain name 2	IP2IP2	TTL2TTL2
域名3Domain 3	IP3IP3	TTL3TTL3

The UE moves, assuming that the UE moves to the MEC platform corresponding to APP1, that is, APP1 is a distributed deployment. Assuming that the DNS record of APP1 has not timed out, that is, TTL1 has not changed to 0, the UE will not re-initiate a DNS query for APP1, so that for APP1, the UE cannot realize the service of accessing the application server nearby.

In addition, in the scenario where the session carries multiple services, as in the previous example, a session carries the services of APP1, APP2, and APP3 at the same time. If only APP1 is deployed in a distributed manner, when the UE moves to the MEC platform corresponding to APP1 When, how can the UE initiate a DNS query only for APP1?

Therefore, the problem to be solved by the present invention is: for distributed deployment services, how to realize the service of accessing the application server nearby when the TTL does not time out.

In order to solve the above-mentioned problems, this application provides a variety of different DNS query methods. To facilitate the understanding of the present invention, some terms or terms appearing in the embodiments of the present application will be explained below.

1. Domain name

In the embodiments of this application, the domain name can be identified by the APP ID, can also be a fully qualified domain name (FQDN), or can be a symbol composed of English letters, Arabic numerals, "-", ".", etc.

2. Application server corresponding to the domain name

In a distributed deployment scenario, the business corresponding to a domain name is a distributed deployment business, and the domain name corresponds to a distributed deployment application server, that is, the domain name corresponds to multiple application servers. In a distributed deployment scenario, the UE can request access to the service from the application server of the central data network element or the application server of the local data network, so that nearby access to the service can be realized.

In a centralized deployment scenario, the service corresponding to the domain name is a centralized deployment service, and the domain name corresponds to a centralized deployment application server, that is, the domain name corresponds to an application server.

3. Registration Area (RA)

After the AMF receives the registration request from the UE, it will allocate an RA to the UE. When the UE moves within the RA, it will not initiate a mobile registration process. RA consists of one or more tracking area identifiers (TAI).

4. Domain name scope

The domain name range refers to the coverage of the IP address corresponding to the domain name, that is, the coverage of the application server corresponding to the domain name. The domain name range indicates the service range of the application server. The UE moves within the domain name range, and the IP address corresponding to the domain name of the service corresponding to the application server does not change. This range can be represented by a data network access identifier (DN access identifier, DNAI), or can be represented by TAI.

As an example, Table 2 shows the correspondence between the domain name, the application server corresponding to the domain name, and the domain name range.

Table 2

Regarding Table 2, it can be seen that there are multiple application servers corresponding to the domain name, and the domain name range includes DNAI1 and DNAI2. There is one application server corresponding to domain name 2, and the domain name range is PLMN, which means that the domain name range is the entire operator network. There are multiple application servers corresponding to domain name 3, and the domain name range includes DNAI1, DNAI3, and DNAI5. Optionally, the domain name range of domain name 2 may also be empty or other special values to indicate that the domain name range of the domain name covers the entire operator network.

5. The intersection area between the UE's registration area and the domain name range

For example, UE1's RA={TA1, TA2, TA3}, the domain names accessed by UE1 include domain name 1 and domain name 2, and domain name 1 range = {DNAI1, DNAI2}, domain name 2 range = {DNAI3}, DNAI1 = {TA1, TA2 }, DNAI2={TA4}, DNAI3={TA4}, that is, domain name 1 range={TA1, TA2, TA4}, domain name 2 range={TA4}.

Therefore, the intersection area of the range of RA and domain name 1 is {TA1, TA2}. It can be understood that the domain name 1 exists in the RA coverage of UE1. That is to say, when UE1 moves in the intersection area, if it visits domain name 1, it can visit nearby.

The intersection area of the range of RA and domain name 2 is an empty set. It can be understood that the domain name 2 does not exist in the RA coverage of UE1. Since there is no intersection area within the RA range, UE1 cannot achieve nearby access when it moves within the RA range. UE1 can access the service corresponding to domain name 2 by accessing the center DN, or by accessing application servers deployed in other locations. Access the business corresponding to domain name 2.

The following describes the solutions provided by this application.

Based on the architecture shown in FIG. 1 or FIG. 2, as shown in FIG. 4A, the present application provides a DNS query method. The method can be executed by PCF, DNS server, and UE, and can also be used for PCF components (such as chips, circuits, etc.), components used for DNS server (such as chips, circuits, etc.), and components used for UE (such as chips). , Circuit, etc.) execution. The method may also be executed by the DNS server and the UE, or executed by components (such as chips, circuits, etc.) used for the DNS server and components (such as chips, circuits, etc.) used for the UE.

For the convenience of description, the following takes the method executed by the PCF, DNS server and UE as an example for description.

The method includes the following steps:

Step 401a: Obtain domain name information of an application of the UE, where the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name.

Optionally, as another implementation method, the domain name information may also be used to indicate whether there is one application server corresponding to the domain name.

Optionally, the domain name information includes a domain name and indication information, and the indication information is used to indicate whether there are multiple application servers corresponding to the domain name, or the indication information is used to indicate whether there is one application server corresponding to the domain name.

In the first implementation method, the indication information here may be 1-bit information. The indication information of "1" is used to indicate that there is one application server corresponding to the domain name, and the indication information of "0" is used to indicate that there are multiple application servers corresponding to the domain name. Alternatively, the indication information being "0" is used to indicate that there is one application server corresponding to the domain name, and the indication information being "1" is used to indicate that there are multiple application servers corresponding to the domain name.

In the second implementation method, when the domain name information includes a domain name and indication information, the indication information is used to indicate that there is one application server corresponding to the domain name, and the indication information may be any information. The domain name information only contains the domain name, and when it does not contain the instruction information, it is used to indicate that there are multiple application servers corresponding to the domain name.

In the third implementation method, when the domain name information includes a domain name and indication information, the indication information is used to indicate that there are multiple application servers corresponding to the domain name, and the indication information may be any information. The domain name information only contains the domain name, and when it does not contain the instruction information, there is one application server used to indicate the domain name.

Among them, the methods for PCF to obtain the domain name information of the application domain name include but are not limited to:

Method 1. The PCF receives domain name information from the centralized control network element.

The centralized control network element here can be a centralized MEC platform, a UDR, or a management and control platform (such as an Operation, Administration and Management (OAM) platform), or an NRF. When the centralized control network element is UDR, OAM, or NRF, the MEC platform can register the domain name information on the UDR, OAM, or NRF, or the MEC platform can register the domain name information and domain name range on the UDR, OAM, or NRF.

In this method, the PCF may request the centralized control network element for domain name information, or the centralized control network element may actively send the domain name information to the PCF.

Optionally, the PCF may also request the centralized control network element to obtain the domain name range of the domain name, or the centralized control network element may actively send the domain name range to the PCF.

Method 2: The PCF receives the service description information corresponding to the domain name and the service location corresponding to the service description information from the centralized control network element, and determines the domain name information of the domain name according to the service description information and the service location.

Specifically, when there are multiple service locations corresponding to the service description information, the PCF determines that the domain name information of the domain name of the service corresponding to the service description information is used to indicate that there are multiple application servers corresponding to the domain name; when the service description information corresponds to When there is only one service location, the PCF determines that the domain name information of the domain name of the service corresponding to the service description information is used to indicate that there is one application server corresponding to the domain name.

Step 402a, the PCF sends domain name information to the UE. Correspondingly, the UE can receive the domain name information.

The domain name information is used by the UE to determine whether to send the first message, and the first message is used to query the IP address corresponding to the domain name.

Optionally, the PCF may also determine the intersection area between the registration area of the UE and the domain name range of the domain name, and then the PCF sends the intersection area to the UE.

Optionally, the AMF may determine the intersection area between the registration area of the UE and the domain name range of the domain name, and then the AMF sends the intersection area to the UE.

Optionally, the intersection area can be included in the domain name information, or can be used as an independent cell. When the intersection area is used as an independent cell, the PCF or AMF sends the domain name and the corresponding intersection area to the UE.

Optionally, the domain name information can be issued to the UE by the PCF through the UE policy. The UE policy may specifically be a UE Route Selection Policy (URSP), that is, the URSP includes domain name information.

In step 403a, the UE determines that it moves.

For example, the movement of the UE here may be cell-granular movement, that is, when the UE moves from one cell to another cell, the UE determines that the movement occurs.

For another example, the movement of the UE here may also be a movement of TA granularity, that is, when the UE moves from one TA to another TA, the UE determines that the movement occurs.

For another example, the movement of the UE here may also be a movement of DNAI granularity, or understood as: the movement of the UE causes the corresponding DNAI change of the UE. That is, when the UE moves from one DNAI to another DNAI, the UE determines that the movement occurs. Among them, the movement of the UE with the granularity of DNAI refers to the movement between the UPF corresponding to the DNAI of the UE, that is, the UE moves out of the UPF corresponding to the DNAI. Optionally, the UE can sense DNAI changes in the following ways:

Manner 1: Configure the corresponding relationship between TA and DNAI on the UE.

After the UE moves in TA, it can judge whether DNAI moves in accordance with the movement of TA. For example, DNAI={TA1, TA2}, DNAI2={TA3}, when the UE moves from TA1 to TA3, the UE moves with the granularity of DNAI; when the UE moves from TA1 to TA2, the UE moves with the granularity of TA, but no The movement of DNAI granularity.

Manner 2: SMF sends a DNAI change notification to the UE. That is, when the SMF detects a change in DNAI, it sends a notification to the UE.

For another example, the movement of the UE here can also be a movement of the granularity of the intersection area between the UE's registration area and the domain name range, that is, for a certain domain name, when the UE moves out of the intersection area between the UE's registration area and the domain name range When the time, the UE determines that it is moving.

Step 404a: In the case that the retention time of the DNS resource record corresponding to the domain name of the application has not expired, the UE determines that the first condition is met, and then sends a first message to the DNS server. The first message is used to query the domain name corresponding to the domain name. IP address.

The first condition here is: there are multiple application servers corresponding to the domain name. Or the first condition is: there are multiple application servers corresponding to the domain name, and the UE has moved out of the intersection area, and the intersection area is the intersection area between the registration area of the UE and the domain name range of the domain name.

In the foregoing first implementation method, as long as it is determined that there are multiple application servers corresponding to the domain name, it is determined that the first condition is satisfied, and it is not necessary to judge whether other conditions are satisfied, such as judging whether the UE has moved out of the intersection area. In the second implementation method, on the one hand, it is necessary to determine that there are multiple application servers corresponding to the domain name, and on the other hand, it is also necessary to determine that the UE moves out of the intersection area. Therefore, the conditions of the first realization method are more relaxed and the judgment actions are less, and the conditions of the second realization method are more stringent and the judgment actions are more. This second implementation method can reduce the number of times the UE initiates DNS queries.

It should be noted that the DNS server can be an application server deployed by a third party or an operator, or it can be integrated as a function on PCF, AMF, or SMF, and the DNS server can also be a configuration server or an enable server in the MEC platform.

Step 405a: The DNS server sends a second message to the UE, and correspondingly, the UE can receive the second message.

As an implementation manner, regardless of whether the IP address corresponding to the domain name queried by the DNS server is the same as the IP address corresponding to the domain name sent to the UE last time, the DNS server will re-send the IP address to the UE. In this case, the second message includes the IP address corresponding to the domain name, the application server indicated by the IP address corresponds to the location of the UE after it has moved, and the IP address may be the IP address corresponding to the domain name sent to the UE last time. The address is the same, it may be different. Optionally, the second message may also include the domain name.

As another implementation method, when the IP address corresponding to the domain name queried by the DNS server is different from the IP address corresponding to the domain name sent to the UE last time, the DNS server will resend the IP address to the UE; when the DNS server queries When the IP address corresponding to the domain name is the same as the IP address corresponding to the domain name sent to the UE last time, the DNS server will not re-send the IP address to the UE, but send an indication message, which is used to indicate the domain name The IP address of the corresponding application server has not changed, or the indication information is used to instruct the UE to use the original DNS resource record. In this case, the second message may include indication information, and may also include an IP address. Further, the second message may also include the domain name.

It should be noted that after the UE receives the above second message, if the second message includes an IP address, the UE may also update the DNS resource record according to the IP address. For example, one update method is: replacing the IP address in the original DNS resource record with the newly received IP address. For another example, another update method is: delete the original DNS resource record, and regenerate a DNS resource record, which contains the domain name and the newly received IP address. It should be noted that if the second message also contains a TTL, the TTL corresponding to the DNS resource record also needs to be updated. For another example, another update method is: the UE deletes the original DNS resource record before sending 404a, and generates a new DNS resource record after receiving 405a.

Optionally, the above-mentioned first message is a DNS query request, or a DNS query message, or a query request, or a query message. The aforementioned second message is a DNS query response, or a DNS response message, or a query response, or a response message.

According to the prior art, when the UE moves, if the retention time of the DNS resource record corresponding to the applied domain name does not expire at the location after the move, the UE will use the IP address in the DNS resource record for service access at this time. , The UE does not access the application server corresponding to the location where the UE is located after moving, and therefore cannot achieve nearby access.

Based on the above-mentioned embodiments of this application, after the UE moves, if the retention time of the DNS resource record does not expire, as long as the first condition is met, the UE will initiate a query to the DNS server for the IP address corresponding to the domain name, and the IP The application server indicated by the address corresponds to the location of the UE after it has moved, thereby realizing nearby access to the service.

It should be noted that, as an alternative implementation solution, the operations performed by the PCF in the above embodiments may also be performed by the DNS server.

It should be noted that any of the steps described above for the PCF to send relevant information to the UE may be actually executed by the PCF sending the information to the UE through other network elements, such as AMF and RAN.

Based on the architecture shown in FIG. 1 or FIG. 2, as shown in FIG. 4B, this application provides yet another DNS query method. The method can be executed by the DNS server and the UE, and can also be executed by components (such as chips, circuits, etc.) used for the DNS server and components (such as chips, circuits, etc.) used for the UE.

For the convenience of description, the following takes the method executed by the DNS server and the UE as an example for description.

The method includes the following steps:

In step 401b, the UE sends a DNS query request to the DNS server, and the DNS query request includes the domain name of the application. Correspondingly, the DNS server can receive the DNS query request.

Step 402b: The DNS server sets a TTL according to the domain name information of the domain name, where the TTL is the TTL of the DNS resource record corresponding to the domain name.

For example, if the domain name information indicates that there are multiple application servers corresponding to the domain name, the TTL is set to be less than a preset threshold. For another example, if the domain name information indicates that there is one application server corresponding to the domain name, then the TTL is set to be greater than a preset threshold. Optionally, the DNS server may obtain the preset threshold through a pre-configuration method.

Step 403b: The DNS server sends the IP address and TTL corresponding to the domain name to the UE. The TTL is used by the UE to determine whether to send a first message, and the first message is used to query the IP address corresponding to the domain name. Correspondingly, the UE can receive the IP address and TTL corresponding to the domain name.

In step 404b, the UE determines that it moves.

For the implementation method of this step, refer to step 403a of the embodiment in FIG. 4A.

Step 405b: In the case that the retention time of the DNS resource record corresponding to the domain name of the application has not expired, the UE determines that the first condition is satisfied, and then sends a first message to the DNS server, and the first message is used to query the domain corresponding to the domain name. IP address.

The first condition here is: the TTL of the DNS resource record is less than the preset threshold. The TTL is the TTL sent to the UE in step 403b.

It should be noted that the first condition may also be: the TTL of the DNS resource record is less than the preset threshold, and the UE has moved out of the intersection area between the registration area of the UE and the domain name range of the domain name. That is, before step 401b described in this method, the AMF or PCF may also determine the intersection area between the registration area of the UE and the domain name range of the domain name, and send the intersection area to the UE. For details, refer to the description of step 402a.

In step 406b, the DNS server sends a second message to the UE, and correspondingly, the UE can receive the second message.

This step is the same as step 405a in the embodiment of FIG. 4A, and reference may be made to the foregoing description.

It should be noted that the UE can obtain the preset threshold of TTL through, but not limited to, the following methods:

Method 1: Pre-configuration method.

When the control platform or UE leaves the factory, the preset threshold is configured on the UE.

Manner 2: In the process, the AMF or SMF sends the preset threshold to the UE.

For example, a preset threshold is configured on the AMF; in the registration process, the AMF sends the preset threshold to the UE through a registration acceptance message.

For another example, a preset threshold is configured on the UDM; in the registration process, the AMF obtains the preset threshold from the UDM, and sends the preset threshold to the UE through a registration acceptance message.

For another example, a preset threshold is configured on the SMF; in the session establishment process, the SMF sends the preset threshold to the UE through a registration acceptance message.

For another example, a preset threshold is configured on the UDM; in the session establishment process, the SMF obtains the preset threshold from the UDM, and sends the preset threshold to the UE through a session establishment acceptance message.

Based on the above-mentioned embodiments of this application, after the UE moves, if the retention time of the DNS resource record does not expire, as long as the first condition is met, the UE will initiate a query to the DNS server for the IP address corresponding to the domain name, and the IP The application server corresponding to the address corresponds to the location of the UE after it has moved, thereby realizing nearby access to the service.

The following describes the embodiments shown in FIGS. 4A to 4B in combination with specific embodiments.

As shown in Fig. 5, it is a schematic flowchart of another DNS query method provided by this application. This embodiment is a specific implementation of the embodiment shown in FIG. 4A.

The method includes the following steps:

Step 500: The MEC platform sends a registration message to the PCF. Correspondingly, the PCF can receive the registration message.

The registration message carries domain name information. The registration message may specifically be an application function request message (AF request).

Optionally, the registration message may also carry a domain name range. At this time, the PCF saves the corresponding relationship between the domain name information and the domain name range.

The registration message can be sent directly to the PCF by the MEC platform, or sent to the PCF via the NEF.

In step 501, the AMF sends a UE policy association request to the PCF. Accordingly, the PCF can receive the UE policy association request.

The UE policy association request carries a permanent subscription identifier (Subscription Permanent Identifier, SUPI), registration area, access type (access type), user location information (User location information, ULI), and radio access technology type (Radio Access Technology type, RAT type) and other information.

It should be noted that the AMF sends a UE policy association request to the PCF during the registration process of the UE. That is, after the AMF receives the registration request sent by the UE, it sends a UE policy association request to the PCF.

Optionally, the AMF also sends the registration area to the PCF.

As an implementation method, in the corresponding service operation, the UE policy association request can be described as Npcf_UEPolicyControl_Create Request.

In step 502, the PCF returns a UE policy association response to the AMF, and accordingly, the AMF can receive the UE policy association response.

The UE policy association response carries a UE policy association ID (UE policy association ID), and the UE policy association ID is used to index the UE policy of the UE on the PCF.

Similarly, in the corresponding servicing operation, the UE policy association response can be described as Npcf_UEPolicyControl_Create Response.

In step 503a, the PCF determines the intersection area between the registration area of the UE and the domain name range of the domain name.

When the registration message of step 500 carries the domain name range and the UE policy association request of step 501 carries the registration area, step 503a can be executed. When the UE policy association request in step 501 does not carry the registration area, the PCF can determine the domain name range according to the domain name range in step 500.

This step is optional.

In step 503, the PCF determines the UE policy.

For example, the PCF determines the UE policy according to the domain name information in the registration message in step 500 and the SUPI obtained in step 501, that is, determines the domain name information related to a certain UE from multiple domain names. Among them, the UE policy includes domain name information. When step 503a is executed, the UE policy includes domain name information, the intersection area between the registration area of the UE and the domain name range of the domain name.

As an implementation method, the UE strategy can be implemented by URSP. That is, the URSP includes domain name information, and optionally also includes the intersection area between the registration area of the UE and the domain name range of the domain name.

In step 504, the PCF sends a delivery message to the AMF, which carries the UE policy. Correspondingly, the AMF can receive the delivery message.

As an implementation method, corresponding to the service operation, the transfer message can be described as Namf_Communication_N1N2MessageTransfer.

Step 505: When the UE is in an idle state, the AMF triggers paging to the UE.

This step is optional.

Step 506: When the UE is in the connected state, the AMF sends the UE policy to the UE.

Step 507: The UE sends a response message to the AMF.

That is, after receiving the UE policy, the UE sends a response message to the AMF.

This step is optional.

In step 508, the AMF sends a response message to the PCF.

That is, after the AMF receives the UE policy, it sends a response message to the PCF.

This step is optional.

As an implementation method, corresponding to the service operation, the response message can be described as Namf_Communication_N1MessageNotify.

In step 509, the UE determines that it moves.

In step 510, the UE determines to re-initiate the DNS query.

The following describes how the UE determines to re-initiate the DNS query in different situations.

Case 1: The TTL in the DNS resource records stored locally by the UE expires.

Due to the TTL timeout, the IP address corresponding to the domain name in the DNS resource record is invalid, and the UE determines to re-initiate the DNS query to obtain the IP address corresponding to the domain name again.

Case 2: The TTL in the DNS resource records stored locally by the UE does not expire.

In view of this situation, this application provides two different implementation methods to determine whether to re-initiate the DNS query.

Method 1: The UE determines whether to re-initiate the DNS query according to the domain name information.

This method is aimed at the situation where the UE receives domain name information.

When the UE moves, it is judged according to the domain name information whether the domain name corresponding to the session of the UE needs to re-initiate the DNS query. If the domain name information indicates that there are multiple application servers corresponding to the domain name, that is, there are multiple IP addresses corresponding to the application servers, it is determined to re-initiate a DNS query for the domain name. If the domain name information indicates that there is one application server corresponding to the domain name, that is, there is one IP address corresponding to the application server, it is determined not to initiate a DNS query for the domain name.

As an example, the session of the UE has service 1, service 2, and service 3, corresponding to domain name 1, domain name 2, and domain name 3, respectively, and the respective domain name information indicates that there are multiple, one, and one IP addresses corresponding to the application server. Then, when the UE moves, the UE only needs to re-initiate the DNS query for the domain name 1, but does not need to initiate the DNS query for the domain name 2 and the domain name 3.

Method 2: The UE determines whether to re-initiate the DNS query according to the domain name information and the intersection area between the registration area of the UE and the domain name range of the domain name.

This method is aimed at the situation where the UE receives the domain name information and the intersection area between the registration area of the UE and the domain name range of the domain name.

When the UE moves, according to the domain name information and the intersection area between the registration area of the UE and the domain name range of the domain name, it is judged whether the domain name corresponding to the session of the UE needs to re-initiate the DNS query. The UE determines that the UE has moved out of the intersection area between the registration area of the UE and the domain name range of the domain name, and the domain name information indicates that the domain name corresponds to multiple application servers, then the UE determines to re-initiate a DNS query for the domain name; otherwise, the above conditions are not met , The UE does not initiate a DNS query for the domain name.

As an example, the UE’s session has service 1, service 2, and service 3, which correspond to domain name 1, domain name 2, and domain name 3, respectively. The respective domain name information indicates that the IP address corresponding to the application server is multiple, 1, and 1, respectively. The intersection area between the registration area and the domain name range of the domain name is {TA1, TA2}, {PLMN}, {TA1; TA3, TA4, TA5, TA8}. Then, for domain name 1, when the UE moves out of the intersection area of domain name 1, that is {TA1, TA2}, just re-initiate DNS query; for domain name 2, the domain name information of domain name 2 indicates that the IP address corresponding to the application server is 1 , There is still no need to initiate a DNS query; for domain name 3, since the domain name information of domain name 3 indicates that the IP address corresponding to the application server is 1, although the UE moves out of the intersection area of domain name 3, there is still no need to initiate a DNS query.

Step 511: The UE initiates a DNS query process.

The process of sending the DNS query by the UE is in the prior art, and the foregoing description of this application can be referred to, which is not repeated here.

After the UE initiates the DNS query process, it can retrieve the IP address and TTL corresponding to the domain name, and then the UE updates the DNS resource record according to the IP address and TTL.

Subsequently, the UE uses the IP address in the updated DNS resource record to access the service, and the new IP address is the IP address of the application server closest to the UE, thereby realizing the nearby access service of the UE.

For the embodiment shown in FIG. 5, several other optional implementation schemes are given below.

Alternative 1: The PCF in the embodiment of FIG. 5 determines the intersection area between the registration area of the UE and the domain name range of the domain name. Modified to: the AMF determines the intersection area between the registration area of the UE and the domain name range of the domain name and sends it To UE.

Based on this solution, the changes to the embodiment in FIG. 5 are as follows:

1. Delete step 503a, and the UE policies of steps 503, 504, and 506 do not include the intersection area between the registration area of the UE and the domain name range of the domain name.

2. In step 501, the registration area (RA) of the UE is not carried.

3. The operation of "PCF sending domain name range to AMF" is added. For example, the domain name range can be sent to AMF in step 504 or the domain name range can be sent to AMF through a new step; for example, the domain name range can be sent to AMF in step 502.

Or, configure the domain name and domain name range on the AMF, and there is no need to add the operation of "PCF sending domain name range to AMF" at this time.

4. Add the operation of "AMF determines the intersection area between the registration area of the UE and the domain name range of the domain name, and sends the intersection area to the UE". The specific implementation may be that the AMF modifies the UE policy in step 504 so that the UE policy includes the intersection area; it may also be that the AMF sends the intersection area to the UE through a registration acceptance message. This process occurs after step 502 and before step 503.

Alternative 2: In the embodiment of FIG. 5, the MEC platform actively sends a registration message to the PCF, which is modified as follows: the PCF actively requests domain name information from the centralized control network element, and optionally also requests domain name range.

Based on this solution, the changes to the embodiment in FIG. 5 are as follows:

1. Delete step 500.

2. Step 500a to step 500b are added, and step 500a to step 500b are executed in any step before step 503a.

among them:

In step 500a, the PCF sends a domain name query request to the centralized control network element. The domain name query request is used to request domain name information, or the domain name query request is used to request domain name information and domain name range.

In step 500b, the centralized control network element sends a domain name query response to the PCF, where the domain name query response includes domain name information, or the domain name query response includes domain name information and a domain name range.

As an implementation method, the interaction between the PCF and the centralized control network element can be implemented through NEF.

Alternative 3: In the embodiment of FIG. 5, the registration message in step 500 carries domain name information and domain name range (optional), and is modified as follows: the registration message does not carry domain name information, but carries location (DNAI) and service Descriptive information and domain name range (optional).

The service description information here can be represented by any one or more of the following: application identifier (application identifier), data network name (Data Network Name, DNN), single network slice selection assistance information (single network slice selection assistance information, S- NSSAI), domain name, etc.

Based on this solution, the changes to the embodiment in FIG. 5 are as follows:

1. The registration message in step 500 does not carry domain name information, but carries location (DNAI) and service description information, and optionally, also carries domain name range.

2. Add the step "PCF determines the domain name information based on the received location and service description information".

Specifically, when there are multiple locations corresponding to the service description information, the PCF determines that the domain name information of the domain name of the service corresponding to the service description information indicates that the application server corresponds to multiple IP addresses; when there is only one location corresponding to the service description information , The PCF determines that the domain name information of the domain name of the service corresponding to the service description information indicates that the IP address corresponding to the application server is one.

Alternative 4: In the embodiment of FIG. 5, the MEC platform actively sends a registration message to the PCF, which is modified as follows: the PCF actively requests the location (DNAI), service description information, and domain name range (optional) from the centralized control network element.

Based on this solution, the changes to the embodiment in FIG. 5 are as follows:

1. Delete step 500.

2. Step 500c to step 500d are added, and step 500c to step 500d are executed in any step before step 503a.

among them:

In step 500c, the PCF sends a domain name query request to the centralized control network element, where the domain name query request is used to request the location, service description information, and domain name range (optional).

Step 500d: The centralized control network element sends a domain name query response to the PCF. The domain name query response includes location, service description information, and domain name range (optional).

3. Add the step "PCF determines the domain name information based on the received location and service description information".

It should be noted that the above-mentioned multiple optional solutions can be combined with each other to extend Embodiment 5. For example, the combination of Option 1 and Option 2 is applied to Embodiment 5, and the combination of Option 1 and Option 3 is applied to Embodiment 5, or the combination of Option 1 and Option 3 is applied to Embodiment 5. The combination of 4 is applied to embodiment 5.

As shown in Fig. 6, a schematic flowchart of another DNS query method provided by this application. This embodiment is a specific implementation of the embodiment shown in FIG. 4B. This process occurs when the UE has established a protocol data unit (protocol data unit, PDU) session. For the domain names described below, the corresponding services are all running on the PDU session.

The method includes the following steps:

In step 600, the DNS server saves the domain name information.

Among them, the DNS server can obtain the above-mentioned domain name information through a management and control platform (such as an OAM platform).

Step 601: The UE sends a DNS query request to the DNS server, carrying the domain name.

Step 602: The DNS server sets the value of TTL according to the domain name information.

The DNS server sets TTL, which is described as follows:

When the domain name information indicates that there are multiple IP addresses corresponding to the application server, the value of the TTL is set to be less than the preset threshold.

When the domain name information indicates that the IP address corresponding to the application server is one, the value of the TTL is set to be greater than the preset threshold.

Step 603: The DNS server sends a DNS query response to the UE. Correspondingly, the UE can receive the DNS query response.

The DNS query response includes the IP address and TTL corresponding to the domain name.

In step 604, the UE determines that it moves.

For the specific implementation manner of this step, reference may be made to the related description of step 509 in the embodiment of FIG. 5, which will not be repeated here.

In step 605, the UE determines to re-initiate the DNS query.

Specifically, when the value of TTL is less than the preset threshold, the UE determines that the domain name information indicates that there are multiple IP addresses corresponding to the application server, and then determines to re-initiate the DNS query. Conversely, when the value of TTL is greater than the preset threshold, the UE determines that the domain name information indicates that the IP address corresponding to the application server is 1, and then determines not to initiate a DNS query.

The above description method can also be described as that when the value of TTL is less than the preset threshold, the UE determines to re-initiate a DNS query for the domain name corresponding to TTL; on the contrary, when the value of TT; is greater than the preset threshold, the UE Make sure not to re-initiate the DNS query. Wherein, for the manner in which the UE obtains the preset threshold value, reference may be made to the description of step 406b, which will not be repeated here.

In step 606, the UE initiates a DNS query process.

For the embodiment shown in FIG. 6, an optional implementation scheme is given below: AMF or PCF sends the intersection area of the registration area and domain name range to the UE, and the UE determines whether to re-initiate the DNS query based on the preset threshold and the intersection area.

The way to determine the intersection area is as follows:

For example, in the registration process, the AMF allocates a registration area for the UE, determines the intersection area between the registration area and the domain name range, and sends the intersection area to the UE through a registration acceptance message. Among them, AMF can obtain the domain name range through configuration or from PCF.

For another example, the AMF sends the registration area to the PCF, and the PCF determines the intersection area according to the registration area and the domain name range, and sends it to the UE in the form of a UE policy, or the PCF sends the intersection area to the AMF, and the AMF sends it to the UE through a registration acceptance message . Among them, the PCF can obtain the domain name range through configuration or from the management and control platform.

According to the above description, step 605 can be described as: when the value of TTL is less than the preset threshold and the UE moves out of the intersection area corresponding to the domain name, the UE determines to re-initiate the DNS query. Conversely, when the value of TTL is greater than the preset threshold, or the UE does not move out of the intersection area corresponding to the domain name, the UE determines not to re-initiate the DNS query.

The foregoing mainly introduces the solution provided by this application from the perspective of interaction between various network elements. It can be understood that, in order to realize the above-mentioned functions, each network element described above includes hardware structures and/or software modules corresponding to each function. Those skilled in the art should easily realize that in combination with the units and algorithm steps of the examples described in the embodiments disclosed herein, the present invention can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed by hardware or computer software-driven hardware depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered as going beyond the scope of the present invention.

The embodiments of the present application also provide a device for implementing any of the above methods. For example, a device is provided that includes units (or means) for implementing each step performed by the terminal device in any of the above methods. For another example, another device is also provided, including a unit (or means) for implementing each step performed by the policy control network element in any of the above methods. For another example, another device is also provided, including a unit (or means) for implementing each step executed by the DNS server in any of the above methods.

For example, please refer to FIG. 7, which is a schematic diagram of a communication device provided by an embodiment of the application. The device is used for terminal equipment. As shown in FIG. 7, the device 700 includes a sending unit 710 and a receiving unit 720.

In the first solution: the sending unit 710 is configured to send the DNS resource record to the DNS if the first condition is met when the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired. The server sends a first message, and the first message is used to query the Internet Protocol IP address corresponding to the domain name. The receiving unit 720 is configured to receive a second message sent by the DNS server, where the second message includes an IP address corresponding to the domain name, and the application server indicated by the IP address corresponds to the moved position of the terminal device .

In the second solution: the sending unit 710 is configured to send the DNS resource record to the DNS if the first condition is met when the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device does not expire. The server sends a first message, and the first message is used to query the Internet Protocol IP address corresponding to the domain name. The receiving unit 720 is configured to receive a second message sent by the DNS server, where the second message includes indication information, and the indication information is used to indicate that the IP address corresponding to the domain name has not changed, and the IP address indicates The application server of corresponds to the position of the terminal device after it has moved.

Based on the first scheme or the second scheme above:

In a possible implementation method, the first condition includes any one of the following: there are multiple application servers corresponding to the domain name; or, there are multiple application servers corresponding to the domain name, and the terminal device is removed The intersection area is an intersection area between the registration area of the terminal device and the domain name range of the domain name; or, the retention time of the DNS resource record is less than a preset threshold.

For example, please refer to FIG. 8, which is a schematic diagram of a communication device provided by an embodiment of the application. The device is used for a policy control network element or a DNS server. As shown in FIG. 8, the device 800 includes an acquiring unit 810 and a sending unit 820. Optionally, a determining unit 830 may also be included. The obtaining unit 810 is configured to obtain domain name information of an application of the terminal device, where the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name. The sending unit 820 is configured to send the domain name information to the terminal device, where the domain name information is used by the terminal device to determine whether to send a first message, and the first message is used to query the IP address corresponding to the domain name.

In a possible implementation method, the determining unit 830 is configured to determine the intersection area between the registration area of the terminal device and the domain name range of the domain name; the sending unit 820 is further configured to send the terminal device to the terminal device. The intersection area, the intersection area is used by the terminal device to determine whether to send the first message.

In a possible implementation method, the acquiring unit 810 is specifically configured to receive the domain name information from the centralized control network element; or, receive the service description information corresponding to the domain name and the service description information corresponding to the centralized control network element. The business location of, the domain name information is determined according to the business description information and the business location.

For example, please refer to FIG. 9, which is a schematic diagram of a communication device provided by an embodiment of the application. The device is used for a DNS server. As shown in FIG. 9, the device 900 includes a receiving unit 910, a sending unit 920, and a determining unit 930. The receiving unit 910 is configured to receive a DNS query request from a terminal device, where the DNS query request includes a domain name of an application of the terminal device. The determining unit 930 is configured to set a retention time according to the domain name information of the domain name, where the retention time is the retention time of the DNS resource record corresponding to the domain name. The sending unit 920 is configured to send the Internet Protocol IP address corresponding to the domain name and the retention time to the terminal device, where the retention time is used by the terminal device to determine whether to send a first message, and the first message is used To query the IP address corresponding to the domain name.

In a possible implementation method, the determining unit 930 is specifically configured to: if the domain name information indicates that there are multiple application servers corresponding to the domain name, set the retention time to be less than a preset threshold; or, if the domain name information The domain name information indicates that there is one application server corresponding to the domain name, and the retention time is set to be greater than a preset threshold.

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

In an example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above methods, for example: one or more application specific integrated circuits (ASICs), or, one or Multiple microprocessors (digital singnal processors, DSPs), or, one or more field programmable gate arrays (Field Programmable Gate Arrays, FPGAs), or a combination of at least two of these integrated circuits. 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 processors that can call programs. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

The above receiving unit (for example, the receiving unit) is an interface circuit of the device for receiving signals from other devices. For example, when the device is implemented as a chip, the receiving unit is an interface circuit used by the chip to receive signals from other chips or devices. The above unit for sending (for example, the sending unit) is an interface circuit of the device for sending signals to other devices. For example, when the device is implemented as a chip, the sending unit is an interface circuit used by the chip to send signals to other chips or devices.

Refer to FIG. 10, which is a schematic structural diagram of a terminal device according to an embodiment of the application. The terminal device is used to implement the operation of the terminal device in the above embodiment. As shown in FIG. 10, the terminal equipment includes: an antenna 1010, a radio frequency device 1020, and a signal processing part 1030. The antenna 1010 is connected to the radio frequency device 1020. In the downlink direction, the radio frequency device 1020 receives the information sent by the access network device through the antenna 1010, and sends the information sent by the access network device to the signal processing part 1030 for processing. In the upstream direction, the signal processing part 1030 processes the information of the terminal equipment and sends it to the radio frequency device 1020. The radio frequency device 1020 processes the information of the terminal equipment and sends it to the access network equipment via the antenna 1010.

The signal processing part 1030 is used to realize the processing of each communication protocol layer of the data. The signal processing part 1030 may be a subsystem of the terminal device, and the terminal device may also include other subsystems, such as a central processing subsystem, which is used to process the terminal device operating system and application layer; another example is peripheral sub-systems. The system is used to realize the connection with other equipment. The signal processing part 1030 may be a separately provided chip. Optionally, the above devices may be located in the signal processing part 1030.

The signal processing part 1030 may include one or more processing elements 1031, for example, including a main control CPU and other integrated circuits. In addition, the signal processing part 1030 may further include a storage element 1032 and an interface circuit 1033. The storage element 1032 is used to store data and programs. The program used to execute the method executed by the terminal device in the above method may or may not be stored in the storage element 1032, for example, stored in a memory other than the signal processing part 1030 During use, the signal processing part 1030 loads the program into the cache for use. The interface circuit 1033 is used to communicate with the device. The above device may be located in the signal processing part 1030, the signal processing part 1030 may be realized by a chip, the chip includes at least one processing element and an interface circuit, wherein the processing element is used to perform each step of any method executed by the above terminal device, the interface The circuit is used to communicate with other devices. In one implementation, the unit that implements each step in the above method can be implemented in the form of a processing element scheduler. For example, the device includes a processing element and a storage element, and the processing element calls a program stored by the storage element to execute the above method embodiments. The method executed by the terminal device. The storage element may be a storage element whose processing element is on the same chip, that is, an on-chip storage element.

In another implementation, the program used to execute the method executed by the terminal device in the above method may be a storage element on a different chip from the processing element, that is, an off-chip storage element. At this time, the processing element calls or loads a program from the off-chip storage element on the on-chip storage element to call and execute the method executed by the terminal device in the above method embodiment.

In yet another implementation, the unit of the terminal device that implements each step in the above method may be configured as one or more processing elements, and these processing elements are provided on the signal processing part 1030, where the processing elements may be integrated circuits, such as : One or more ASICs, or, one or more DSPs, or, one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits can be integrated together to form a chip.

The units that implement each step in the above method can be integrated together and implemented in the form of a system-on-a-chip (SOC), and the SOC chip is used to implement the above method. The chip can integrate at least one processing element and a storage element, and the processing element can call the stored program of the storage element to implement the method executed by the above terminal device; or, the chip can integrate at least one integrated circuit to implement the above terminal The method executed by the device; or, it can be combined with the above implementations. The functions of some units are implemented in the form of calling programs by processing elements, and the functions of some units are implemented in the form of integrated circuits.

It can be seen that the above apparatus may include at least one processing element and an interface circuit, wherein at least one processing element is used to execute any method executed by the terminal device provided in the above method embodiment. The processing element can execute part or all of the steps executed by the terminal device in the first way: calling the program stored in the storage element; or in the second way: combining instructions through the integrated logic circuit of the hardware in the processor element Part or all of the steps executed by the terminal device are executed in a manner; of course, part or all of the steps executed by the terminal device may also be executed in combination with the first manner and the second manner.

The processing element here is the same as the above description, and it may be a general-purpose processor, such as a CPU, or one or more integrated circuits configured to implement the above method, such as: one or more ASICs, or, one or more micro-processing DSP, or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The storage element can be a memory or a collective term for multiple storage elements.

Referring to FIG. 11, a schematic structural diagram of a policy control network element provided by an embodiment of this application is used to implement the operation of the policy control network element in the above embodiment. As shown in FIG. 11, the policy control network element includes: a processor 1110, a memory 1120, and an interface 1130, and the processor 1110, a memory 1120, and the interface 1130 are signal-connected.

The method for the execution of the policy control network element in the above embodiment can be implemented by the processor 1110 calling a program stored in the memory 1120. That is, the device for the policy control network element includes a memory and a processor, and the memory is used to store a program, and the program is called by the processor to execute the method executed by the policy control network element in the above method embodiment. The processor here may be an integrated circuit with signal processing capability, such as a CPU. The device for the policy control network element may 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 DSP, or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. Or, the above implementations can be combined.

Referring to FIG. 12, a schematic structural diagram of a DNS server provided by an embodiment of this application is used to implement the operation of the DNS server in the above embodiment. As shown in FIG. 12, the DNS server includes: a processor 1210, a memory 1220, and an interface 1230, and the processor 1210, the memory 1220, and the interface 1230 are signal-connected.

The method executed by the DNS server in the above embodiment may be implemented by the processor 1210 calling a program stored in the memory 1220. That is, the device for the DNS server includes a memory and a processor, and the memory is used to store a program, which is called by the processor to execute the method executed by the DNS server in the above method embodiment. The processor here may be an integrated circuit with signal processing capability, such as a CPU. The means for the DNS server may be realized by one or more integrated circuits configured to implement the above method. For example: one or more ASICs, or, one or more microprocessors DSP, or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. Or, the above implementations can be combined.

Referring to FIG. 13, a schematic diagram of a communication system provided by an embodiment of this application. The system includes a policy control network element and a mobility management network element. Optionally, the system also includes terminal equipment. The policy control network element is used to obtain domain name information of the application of the terminal device, the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name; and the domain name information is sent to the mobility management network element. The mobility management network element is configured to send the domain name information to the terminal device, where the domain name information is used by the terminal device to determine whether to send a first message, and the first message is used to query the corresponding domain name IP address.

Referring to FIG. 14, a schematic diagram of another communication system provided by an embodiment of this application. The system includes a terminal device and a DNS server. The DNS server is used for a DNS query request from the terminal device, the DNS query request includes the domain name of the terminal device application; the retention time is set according to the domain name information of the domain name, and the retention time is the The retention time of the DNS resource record corresponding to the domain name; sending the IP address corresponding to the domain name and the retention time to the terminal device; the terminal device is configured to determine whether to send the first message according to the retention time, the The first message is used to query the IP address corresponding to the domain name.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, it can be implemented in the form of a computer program product in whole or in part. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. 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, computer, server, or data center. Transmission to another website site, computer, server or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrated with one or more available media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, and a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)).

The various illustrative logic units and circuits described in the embodiments of this application can be implemented by general-purpose processors, digital signal processors, application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, Discrete gates or transistor logic, discrete hardware components, or any combination of the above are designed to implement or operate the described functions. The general-purpose processor may be a microprocessor. Alternatively, the general-purpose processor may 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, multiple microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration. achieve.

In one or more exemplary designs, the aforementioned 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 on the computer-readable medium in the form of one or more instructions or codes. 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 a general-purpose or special computer. For example, such computer-readable media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other device that can be used to carry or store instructions or data structures and Other program code media that can be read by general-purpose or special computers, or general-purpose or special processors. In addition, any connection can be appropriately defined as a computer-readable medium, for example, if the software is from a website, server, or other remote source through a coaxial cable, fiber optic computer, twisted pair, or digital subscriber line (DSL) Or transmitted by wireless means such as infrared, wireless and microwave are also included in the definition of computer-readable media. The mentioned disks and discs include compressed disks, laser disks, optical discs, digital versatile discs (English: Digital Versatile Disc, abbreviated as: DVD), floppy disks and Blu-ray discs. Disks usually copy data with magnetism. Discs usually use lasers to copy data optically. The combination of the above can also be contained in a computer readable medium.

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 by hardware, software, firmware, or any combination thereof. When implemented by software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on the computer-readable medium. The computer-readable medium includes a computer storage medium and a communication medium, where the communication medium includes any medium that facilitates the transfer of a computer program from one place to another. The storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer.

Although the application has been described in combination with specific features and embodiments, it is obvious that various modifications and combinations can be made without departing from the spirit and scope of the application. Correspondingly, the specification and drawings are merely exemplary descriptions of the application as defined by the appended claims, and are deemed to cover any and all modifications, changes, combinations or equivalents within the scope of the application. Obviously, those skilled in the art can make various changes and modifications to the application without departing from the scope of the application. In this way, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application also intends to include these modifications and variations.

Claims

A DNS query method for a domain name system is characterized in that it comprises:

In the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, a first message is sent to the DNS server, and the first message is used for Query the Internet Protocol IP address corresponding to the domain name;

Receiving a second message sent by the DNS server, where the second message includes the IP address corresponding to the domain name, and the application server indicated by the IP address corresponds to the moved position of the terminal device.
The method of claim 1, wherein the first condition includes any one of the following:

There are multiple application servers corresponding to the domain name; or,

There are multiple application servers corresponding to the domain name, and the terminal device has moved out of an intersection area, where the intersection area is the intersection area between the registration area of the terminal device and the domain name range of the domain name; or,

The retention time of the DNS resource record is less than a preset threshold.
The method according to claim 1 or 2, wherein the movement of the terminal device includes:

The terminal device moves between cells; or,

The movement of the terminal device causes the data network access identifier DNAI corresponding to the terminal device to change; or,

The terminal device moves between tracking areas; or,

The terminal device moves out of the intersection area between the registration area of the terminal device and the domain name range of the domain name.
A DNS query method for a domain name system is characterized in that it comprises:

In the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, a first message is sent to the DNS server, and the first message is used for Query the Internet Protocol IP address corresponding to the domain name;

Receive a second message sent by the DNS server, where the second message includes indication information used to indicate that the IP address corresponding to the domain name has not changed, and that the application server indicated by the IP address is different from The position of the terminal device after the movement corresponds.
The method of claim 4, wherein the first condition includes any one of the following:

There are multiple application servers corresponding to the domain name; or,

There are multiple application servers corresponding to the domain name, and the terminal device has moved out of an intersection area, where the intersection area is the intersection area between the registration area of the terminal device and the domain name range of the domain name; or,

The retention time of the DNS resource record is less than a preset threshold.
The method according to claim 4 or 5, wherein the movement of the terminal device includes:

The terminal device moves between cells; or,

The movement of the terminal device causes the data network access identifier DNAI corresponding to the terminal device to change; or,

The terminal device moves between tracking areas; or,

The terminal device moves out of the intersection area between the registration area of the terminal device and the domain name range of the domain name.
A DNS query method for a domain name system is characterized in that it comprises:

Acquiring domain name information of the application of the terminal device, where the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name;

The domain name information is sent to the terminal device, where the domain name information is used by the terminal device to determine whether to send a first message, and the first message is used to query an Internet Protocol IP address corresponding to the domain name.
The method of claim 7, further comprising:

Determining the intersection area between the registration area of the terminal device and the domain name range of the domain name;

Sending the intersection area to the terminal device, where the intersection area is used by the terminal device to determine whether to send the first message.
The method according to claim 7 or 8, wherein obtaining domain name information of an application comprises:

Receiving the domain name information from the centralized control network element; or,

The service description information corresponding to the domain name and the service location corresponding to the service description information are received from the centralized control network element, and the domain name information is determined according to the service description information and the service location.
The method according to any one of claims 7-9, wherein the domain name information includes the domain name and indication information, and the indication information is used to indicate whether there are multiple application servers corresponding to the domain name.
A DNS query method for a domain name system is characterized in that it comprises:

Receiving a DNS query request from a terminal device, where the DNS query request includes a domain name of an application of the terminal device;

Setting a retention time according to the domain name information of the domain name, where the retention time is the retention time of the DNS resource record corresponding to the domain name;

The Internet Protocol IP address corresponding to the domain name and the retention time are sent to the terminal device, where the retention time is used by the terminal device to determine whether to send a first message, and the first message is used to query the domain name correspondence IP address.
The method of claim 11, wherein setting the retention time according to the domain name information of the domain name comprises:

If the domain name information indicates that there are multiple application servers corresponding to the domain name, set the retention time to be less than a preset threshold; or,

If the domain name information indicates that there is one application server corresponding to the domain name, the retention time is set to be greater than a preset threshold.
A communication device, characterized by comprising: a unit for executing the method according to any one of claims 1-3.
A communication device, characterized by comprising: a unit for executing the method according to any one of claims 4-6.
A communication device, characterized by comprising: a unit for executing the method according to any one of claims 7-10.
A communication device, characterized by comprising: a unit for executing the method according to claim 11 or 12.
A computer-readable storage medium, wherein the computer-readable storage medium stores a program, and when the program is called by a processor, the method according to any one of claims 1-12 is executed.
A computer program, characterized in that when the program is called by a processor, the method according to any one of claims 1-12 is executed.
A communication system, characterized in that it includes a policy control network element and a mobility management network element;

The policy control network element is used to obtain domain name information of the application of the terminal device, the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name; and the domain name information is sent to the mobility management network element;

The mobility management network element is configured to send the domain name information to the terminal device, where the domain name information is used by the terminal device to determine whether to send a first message, and the first message is used to query the corresponding domain name Internet Protocol IP address.
The system according to claim 19, wherein the policy control network element is further used to determine the intersection area between the registration area of the terminal device and the domain name range of the domain name; The network element sends the intersection area;

The mobility management network element is further configured to send the intersection area to the terminal device, where the intersection area is used by the terminal device to determine whether to send the first message.
The system according to claim 19 or 20, wherein the policy control network element is used to obtain domain name information of an application of a terminal device, which specifically includes:

Used to receive the domain name information from the centralized control network element; or,

It is used to receive the service description information corresponding to the domain name and the service location corresponding to the service description information from the centralized control network element, and determine the domain name information according to the service description information and the service location.
22. The system according to any one of claims 19-21, wherein the system further comprises the terminal device for:

In the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, a first message is sent to the DNS server, the first message Used to query the IP address corresponding to the domain name;

A second message sent by the DNS server is received, where the second message includes an IP address corresponding to the domain name, and the application server indicated by the IP address corresponds to the moved position of the terminal device.
22. The system according to any one of claims 19-21, wherein the system further comprises the terminal device for:

In the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, a first message is sent to the DNS server, the first message Used to query the IP address corresponding to the domain name;

Receive a second message sent by the DNS server, where the second message includes indication information that is used to indicate that the IP address corresponding to the domain name has not changed, and that the application server indicated by the IP address is different from the The position of the terminal device after the movement corresponds.
The system according to claim 22 or 23, wherein the first condition includes any one of the following:

There are multiple application servers corresponding to the domain name; or,

There are multiple application servers corresponding to the domain name, and the terminal device has moved out of an intersection area, where the intersection area is an intersection area between the registration area of the terminal device and the domain name range of the domain name.
The system according to any one of claims 22-24, wherein the movement of the terminal device includes:

The terminal device moves between cells; or,

The movement of the terminal device causes the data network access identifier DNAI corresponding to the terminal device to change; or,

The terminal device moves between tracking areas; or,

The terminal device moves out of the intersection area between the registration area of the terminal device and the domain name range of the domain name.
A communication method, characterized in that it comprises:

The policy control network element obtains domain name information of the application of the terminal device, where the domain name information is used to indicate whether there are multiple application servers corresponding to the domain name;

Sending, by the policy control network element, the domain name information to the mobility management network element;

The mobility management network element sends the domain name information to the terminal device, where the domain name information is used by the terminal device to determine whether to send a first message, and the first message is used to query the Internet protocol corresponding to the domain name IP address.
The method of claim 26, further comprising:

Determining, by the policy control network element, the intersection area between the registration area of the terminal device and the domain name range of the domain name; sending the intersection area to the mobility management network element;

The mobility management network element sends the intersection area to the terminal device, where the intersection area is used by the terminal device to determine whether to send the first message.
The method according to claim 26 or 27, wherein the policy control network element acquiring the domain name information of the application of the terminal device comprises:

The policy control network element receives the domain name information from a centralized control network element; or,

The policy control network element receives the service description information corresponding to the domain name and the service location corresponding to the service description information from the centralized control network element, and determines the domain name information according to the service description information and the service location.
The method according to any one of claims 26-28, further comprising:

In the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, the terminal device sends a first message to the DNS server, so The first message is used to query the IP address corresponding to the domain name;

The terminal device receives a second message sent by the DNS server, where the second message includes an IP address corresponding to the domain name, and the application server indicated by the IP address corresponds to the position of the terminal device after the movement.
The method according to any one of claims 26-28, further comprising:

In the case that the terminal device moves and the retention time of the DNS resource record corresponding to the domain name of the terminal device application has not expired, if the first condition is met, the terminal device sends a first message to the DNS server, so The first message is used to query the IP address corresponding to the domain name;

The terminal device receives a second message sent by the DNS server, where the second message includes indication information used to indicate that the IP address corresponding to the domain name has not changed, and the application indicated by the IP address The server corresponds to the moved position of the terminal device.