CN117336808A

CN117336808A - Re-placement method for guaranteeing MEC service continuity

Info

Publication number: CN117336808A
Application number: CN202311185471.XA
Authority: CN
Inventors: 吴强; 蔡贵良; 王然; 张怡; 智涟漪
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2023-09-13
Filing date: 2023-09-13
Publication date: 2024-01-02

Abstract

The invention relates to a replay method for guaranteeing MEC service continuity, which comprises the following steps: step S1, mobile terminal MN is on line, registration and session registration flow are completed, session is bound with terminal identity; step S2, the mobile terminal MN is about to switch across gateways, a network layer and an application layer notification cooperative mechanism are triggered, and the application layer perceives the network layer state change; step S3, the mobile terminal MN performs cross-gateway switching, and cooperatively performs network layer switching management and application layer edge application migration flow. The scheme meets the requirements of different scenes and continuity of the service, simplifies the replay flow and network deployment of the MEC service, and trades lower service delay with lower service migration overhead.

Description

Re-placement method for guaranteeing MEC service continuity

Technical Field

The invention relates to a method, in particular to a replay setup method for guaranteeing continuity of MEC (media access control) service, belonging to the technical field of MEC service.

Background

In recent years, with the development of cloud network integration and network computing integration, network connection is developed from tangible entity connection to virtual connection of intangible content, service, computing power and the like, so that mobile scenes and subjects are more ubiquitous, and ubiquitous mobile of terminals, service ends, networks and the like is realized; and secondly, the network is further flattened, and the application of wireless side high-density networking enables the horizontal switching to be more frequent. The change of the paradigm introduces a brand new scene of multi-network fusion and cross overlapping of coverage areas, in which a user adopts multiple systems for access, a network node and a user terminal move at high speed, and the seamless switching capability of the mobile node between multi-access networks is required to be enhanced so as to achieve service continuity.

Due to the existence of fixed mobility anchor points in existing mobile network architecture, existing MEC (Multi-access Edge Computing, i.e. Multi-access edge computing) replay methods have difficulty in well guaranteeing traffic continuity in mobile state. One typical scenario: frequent cross-gateway switching of vehicles running at high speed is difficult to ensure service continuity, and meanwhile ultra-low time delay and ultra-high reliability cannot be met. MEC coverage is limited and frequent cross-gateway handoffs by vehicles are difficult to support for traffic continuity. ETSI (European Telecommunications Standards Institute, the european telecommunications standardization institute) and 3GPP (3 rd Generation Partnership Project, the third generation partnership project) have proposed some MEC service replay schemes. The MEC traffic relocation of ETSI involves MA (Mobility Anchor) in the network layer and ME (Mobile Edge) APP (Application) in the Application layer, there are two schemes, scheme 1: MA switching and APP migration; scheme 2: MA switching, APP does not migrate. Three modes of SSC (Session and Service Continuity ) are proposed by 3 GPP.

In ETSI scheme 1, the MN (Mobile Node, i.e., mobile terminal) leaves the service range of the home MA and moves to the service range of the T-MA (Target MA, i.e., destination mobility anchor). First, the MN performs signal detection, and sends a routing request to the strongest MA, which is set to be T-MA, through the RAN (Radio Access Network, i.e., radio access network). Then, after receiving the routing request, the T-MA initiates a proxy binding update procedure with the AME (Access Manager Network Element, i.e. access and mobility management network element) and the SME (Session Manager Network Element, i.e. session management network element) in the core network, and forwards the IP address allocated to the terminal to the mobile terminal MN through cooperation of the T-MA, AME, SME, where the MN accesses the T-MA. The MN then sends a service request packet to the T-MA containing the IP address assigned by the S-MA (Source MA, i.e., source mobility anchor). The T-MA sends the service data packet to the S-MA according to the source IP address in the data packet, and after the S-MA receives the data packet, the S-MA sends the data packet to an S-MEP (Source Mobile Edge Platform, namely a source mobile edge platform) located in the service range of the S-MA, and the S-MEP sends a corresponding S-APP and simultaneously sends an APP replay request to an MEO (Mobile Edge Orchestrator, namely a mobile edge orchestrator). Next, the MEO, MEPM (Mobile Edge Platform Manager, i.e., mobile edge platform manager), MEP cooperate to perform APP migration management work. After the management work is completed, the S-MEP, the S-MEPM, MEO, T-MEP and the T-MEPM cooperate to migrate the APP instance, and meanwhile, the routing rules in the T-MEP are updated. And then the T-MEP activates the migrated APP (T-APP) for the terminal node MN, and if necessary, the S-MEP terminates the S-APP instance and releases the resources. After the replay of MEC service is completed, MN performs service communication with T-APP through T-MA and T-MEP. In the scheme, the APP is always in the same service range as the MN, so that low time delay and high reliability of MEC service are ensured. When the MN moves across the gateway, the MN leaves the S-MA service range and then sequentially performs MA switching work and APP migration work, so that service continuity cannot be supported, and edge service interruption is caused.

In ETSI scheme 2, the MN leaves the service area of the S-MA and moves to the service area of the T-MA. Firstly, the MN performs signal detection, and the MA with the strongest detected signal is the T-MA. And then the MN sends a routing request to the T-MA, after the MA receives the routing request, the T-MA initiates a proxy binding update process with AME and SME in the core network, and sends an IP address allocated to the terminal node MN through a router by cooperation of the T-MA, AME, SME, and the MN accesses the T-MA. After the MA migration work is completed, the MN sends MEC service data packets to the T-MA, wherein the MEC service data packets contain a source IP address, and the T-MA forwards service messages to the S-MA according to the source IP address. S-MA transmits the message to S-MEP in service range, S-MEP transmits the service message to corresponding S-APP. And then, the S-MEP, the S-APP, the S-MEPM and the MEO cooperate to carry out service management work, and PDU session information of the MN and the S-APP is updated, wherein the PDU session information comprises session ID, IP address, flow rule and the like. After the management work is completed, the S-MEP activates a new session for the MN through the S-MA and the T-MA. The MEC service replay is completed, and the MN performs service communication with the S-APP through the T-MA, the S-MA and the S-MEP. Compared with the scheme 1, the APP is not migrated, the time for the MEC service relocation is reduced, and the service continuity of the MN in the cross-gateway switching is supported to a certain extent. However, this solution comes at the cost of a longer detour forwarding path, resulting in problems of latency, reliability, and route management.

In the first SSC mode of 3GPP, when the MN moves across gateways, the traffic service provided by the network to the MN is not dropped, and the network maintains the initial mobility anchor MA during a session, and does not change due to the mobility of the MN and the change of access network technology, so that the IP address allocated to the MN does not change. This mode can be applied to any session and any access type. However, this mode comes at the cost of a longer detour forwarding path, resulting in problems of latency, reliability, and route management.

In the second SSC mode of 3GPP, when the MN moves across gateways, the network releases the connection service with the MN and the corresponding application session, and the originally allocated IP address is also released. When the mobility anchor point is changed, the SSC mode II releases the original connection, then establishes the connection between the MN and the new mobility anchor point, and allocates an IP address to the MN again. This mode fails to satisfy the service continuity, which causes interruption of the service continuity.

In SSC mode three of 3GPP, when a MN moves across gateways, when the mobility anchor changes, a connection is established with a new session anchor before the change, the new connection also accessing the same data network DN. After the new mobility anchor assigns a new IP address to the MN, the MN is instructed by NAS (Network Attached Server, network access server) signaling to maintain the old IP address for a period of time, and then release the old IP address, with the old session resources correspondingly released. The communication address of the user in this mode will change with the change of the user anchor point, but the service will not be interrupted since a new connection has been established before. However, after this mode is completed, the MN still performs a communication session with the same DN, and the data forwarding path is roundabout and lengthy, resulting in various problems such as latency, reliability, and routing management.

Therefore, when the MN moves across the gateway, the above solution cannot guarantee the continuity of the service and the service quality with low delay and high reliability, and mainly has the following problems:

(1) Existing MEC service replay schemes provide multiple types of session and service continuity modes, e.g., SSC three modes of 3GPP, to meet various continuity requirements for different applications and services. Such schemes are cumbersome in flow, complex in network deployment, and the prior art is not clear how to implement a unified MEC service replay flow to cope with various continuity requirements of different scenarios and services.

(2) When the MN moves across the gateway, the service replay needs to switch the network layer MA and migrate the application layer APP in order, and service communication can be restored after the service replay is completed. The processing time is too long, and exceeds the interruption time range tolerated by the service, so that the service continuity is interrupted. APP does not migrate to a certain extent, so that service continuity is guaranteed, but forwarding paths are roundabout and lengthy, and problems of time delay, reliability, route management and the like are caused.

(3) The APP instance recognizes the mobile terminal identity from an identity location unified communication address (e.g. IP address) and some APP sessions do not support a change of mobile terminal MN communication address, thus the mobility anchor is fixed. When the MN moves across the gateway, the APP migrates, however, the mobility anchor point is fixed, the data packet forwarding path is roundabout, the flow is complex, and the problems of time delay, reliability, route management and the like are caused.

(4) When the MN moves across the gateway, the connection node MA is switched, and the APP needs to be moved to a position close to the user. How to implement notification collaboration between a network and an application, and consistency of network layer connection nodes and target application locations is not clear in the prior art.

(5) Mobile terminal devices exhibit a variety of features such as autopilot, unmanned aerial vehicle, satellite, ocean going vessel, etc. The unified communication address of the identity position and the mobility anchor point combined paradigm in the existing network can not effectively support multi-system access, and the complexity of network deployment and equipment access is increased. Therefore, a new solution is urgently needed to solve the above technical problems.

Disclosure of Invention

The invention provides a replay method for guaranteeing continuity of MEC service, which is used for adapting to various continuity requirements of different scenes and services, realizing low service migration cost and less service time delay, and simplifying replay flow and network deployment of MEC service.

In order to achieve the above object, the technical solution of the present invention is as follows, a playback method for guaranteeing continuity of MEC service, the method comprising the steps of:

Step S1, mobile terminal MN is on line, registration and session registration flow are completed, session is bound with terminal identity;

step S2, the mobile terminal MN is about to switch across gateways, a network layer and an application layer notification cooperative mechanism are triggered, and the application layer perceives the network layer state change;

step S3, the mobile terminal MN performs cross-gateway switching, and cooperatively performs network layer switching management and application layer edge application migration flow.

The step S1 specifically includes the following steps of mobile terminal MN registration and session registration, which specifically includes the following steps:

step S101, a mobile terminal MN is online, has a unique User Identification (UID) of a whole network, and sends a routing request to an Access Service Node (ASN) to which the mobile terminal MN belongs according to the signal strength to request to access the ASN;

step S102, after receiving the route request of MN, ASN sends authentication and authorization request to access and mobility management network element (AME) in core network, AME carries out authentication service for terminal requesting access, judges whether access terminal is legal, AME is legal terminal authorization; ASN distributes proper Route Identification (RID) for authorized MN, and records UID/RID mapping information of MN into local buffer;

step S103, ASN sends UID/RID mapping information update request to the Identity Location Register (ILR) to inform the ILR of the latest mapping information of the mobile terminal;

Step S104, after receiving the updating of the mapping information, the ILR records the mapping information UID/RID of the mobile terminal into a local cache so as to enable a subsequent communication opposite terminal to initiate communication to the MN to inquire the routing information of the MN;

step S105, after the access work is completed, the ASN sends a route request success response to the MN. The MN client Application (APP) establishes a session to an edge APP in the edge data center, the session comprising multiple types, e.g., a communication data unit (PDU) session in a 5G network, a Packet Data Network (PDN) session in a 4G network. Firstly, MN sends a session establishment request to AME in a core network through ASN;

step S106, AME selects session management network element SME for the session which needs to be established by MN according to the RID information of MN;

step S107, AME sends MN session creation request to selected session management network element (SME), SME feeds back response information to AME after receiving the request;

step S108, the AME and the SME cooperate to authenticate the session to be established, and judge whether the session to be established is legal or not, and the session is authorized to be legal;

step S109, SME sends MN session creation request to ASN accessed by MN, ASN receives session request and feeds back response information to SME;

step S110, after receiving the response information, the SME forwards the session information to be created to the AME, and the AME feeds back the response information to the SME after receiving the response information;

Step S111, the ASN establishes an ASN-specific session with the mobile terminal through the access network (RAN), the session identifier is the user identity UID of the MN, the establishment procedure includes sending a session request response message to the mobile terminal MN,

to this end, the MN session establishment with the mobile edge application (ME APP) is completed.

In step S2, the network layer and the application layer notify a collaboration mechanism, which is specifically as follows:

the mutual notification cooperative mechanism can be realized between the operator and the third party application through the information among the policy control network element (PCE), the Application Function (AF) and the network capability opening network element (NEE), so that the third application can timely notify the application when sending the requirement to the network and the MN position and the network state change based on the service characteristics,

in step S201, the application layer subscribes to the network event notification, which may be implemented in 3 ways by AF,

in mode 1, the application layer transmits the request of the application to the network resource through the AF request message, thereby realizing the time delay and the bandwidth requirement required by the network layer for guaranteeing the service,

in mode 2, the application layer subscribes to the network layer for event notification messages, e.g., a cross-gateway handoff of a node occurs, through the AF/NEE, so that when the network detects a subscribed event trigger, the AF is notified immediately,

Mode 3, the application layer adjusts the uplink and downlink and multi-homing strategy to realize the management of the access connection point ASN through the modification process of the AF initiating terminal data route,

step S202, after AF receives subscription information, AF request affecting route policy control information is sent to PCE;

in step S203, the network layer PCE receives an AF subscription message, for example, the Radio Network Information Service (RNIS) senses that the access connection point ASN of the session has changed, the Data Network (DN) access identifier (DNAI) has changed, and the network layer sends a notification message to the application layer, including the changed target data network identifier DNAI, so that the application layer obtains the target ME host location to perform application migration, and ensures the consistency of the access node ASN and the target APP location.

The network layer switching management and application layer edge application migration flow in step S3 is specifically as follows:

the mobile terminal MN is about to leave the service range of the source access service node S-ASN, signal detection is carried out, the signal of the new ASN is detected to be larger than the signal of the S-ASN, the difference of signal intensity exceeds a certain threshold, the ASN is set as a target access service node T-ASN, a mobile application platform of the T-ASN is used as a target mobile application platform T-MEP, the migration of an application layer edge application ME APP is triggered,

The mobile terminal MN performs cross-gateway movement, the application layer edge application ME APP migration flow is divided into 6 modules,

the module 1, mn is separate from the S-ASN,

step S301, the MN is about to leave the service range of the S-ASN, a client APP in the MN sends an application mobile request to an S-MEP in a source edge network, and the S-MEP feeds back a response to the MN;

step S302, enabling application mobility by the S-MEP, preparing for migration of the S-APP, wherein the steps include positioning the S-APP of the MN APP session, arranging session context data and the like;

module 2, MN accesses T-ASN.

Step S303, the step is that the MN network layer carries out switching management and application layer session updating flow;

a module 3, updating the traffic rules for the MN,

step S304, the mobile terminal MN accesses the T-ASN, the S-RNIS receives the switching message of the MN, sends the MN area change notice to the S-MEP, and feeds back the confirmation response to the S-RNIS after the S-MEP receives the switching message;

step S305, S-MEP inquires about a target host T-MEC host capable of receiving information from MN from S-MEPM, S-MEPM forwards the inquiry to MEO, MEO determines the T-MEC host through a series of strategy modes such as operator strategy, mobile strategy, application requirement, application capability, mobile edge system state and the like, and forwards the information to S-MEP through S-MEPM so that S-MEP can be connected with T-MEP, and S-APP and session context information which need to be migrated to T-MEP in S-MEP acquisition platform;

Step S306, the S-MEP queries the affected traffic routing rule including a part of the MN UID of the traffic filter and application information as a part of the application;

step S307, S-MEP sends a flow routing rule update request to T-MEP, wherein the flow routing rule update request contains application information and affected flow routing rules;

step S308, the T-MEP receives an update request from the S-MEP traffic routing rule and updates the local traffic routing rule;

step S309, feeding back a traffic routing rule update response to the S-MEP after the update is completed;

the module 4, application migration management,

step S310, the MN network layer is switched, the T-MEP routing rule is updated, and the MN APP sends an application migration request to the S-MEP;

step S311, S-MEP captures the S-APP status information being serviced and step S305 acquires the completed session context information;

step S312, the S-MEP sends an application migration request to the MEO through the S-MEPM, wherein the application migration request comprises an S-APP ID and an ID of a target node;

step S313, MEO sends an instantiation application request to T-MEPM, and T-MEPM instantiates T-APP at target T-MEC host;

step S314, after the instantiation is completed, the MEO feeds back an application migration response to the S-MEP through the S-MEPM;

step S315, the S-MEP sends an application state information transmission request to the T-MEP, wherein the application state information transmission request comprises the captured state information of the S-APP and session context information;

Step S316, the T-MEP synchronizes the received service state information and the received context information with the T-APP running on the T-MEC host computer and activates the service state information and the received context information;

step S317, the T-MEP sends an application state information transmission response to the S-MEP to indicate whether the service state of the application instance transmission is successful;

step S318, after the service state information and the context information are synchronized, the T-APP instance sends an application instance running notification to the T-MEP;

step S319, the T-MEP forwards a T-APP application instance operation notice to the S-MEP;

step S320, the S-MEP sends an application migration response to the MN APP, and triggers the next module;

a module 5, activating a new traffic routing rule,

step S321, T-APP activates the traffic routing rule to T-MEP;

step S322, T-MEP activates the traffic routing rule;

step S323, the T-MEP forwards the traffic routing rule activation notification to the S-MEP;

step S324, the S-APP sends a request for disabling or updating the local traffic rule to the S-MEP;

step S325, S-MEP receives RNIS area change notification from S-RNIS;

step S326, when the S-MEP receives the traffic route rule activation notification of the T-MEP and the traffic route deactivation or update request of the S-APP, the S-MEP deactivates or updates the corresponding traffic route rule;

And a module 6, terminating the source application.

In step S327, if resources are saved, etc., the S-MEP, S-MEPM, MEO, S-APP, S-RNIS cooperatively terminate the source application.

The network layer switching management flow and the application session update flow in step S303 are specifically as follows:

step S303-1, MN triggers network switching, send the conversation to modify the request to AME, the request message includes conversation ID;

step S303-2, the AME receives the session modification request, sends the session modification request to a session management network element SME corresponding to the session according to the session ID, feeds back the request to the AME session modification response after receiving the request, and performs session modification preparation work;

step S303-3, after the AME receives the response, a session modification command is sent to the MN, and the MN starts a timer to switch networks;

step S303-4, MN initiates a route request to T-ASN, wherein the request contains authorization information and requests to access T-ASN;

step S303-5, the T-ASN receives the route request, distributes the new route identification RID2 to the MN, and records the mapping information of the UID/RID2 into a local cache;

step S303-6, the T-ASN establishes a temporary transmission tunnel to the S-ASN, and simultaneously the T-ASN sends a mapping information update request to the ILR, and after receiving the update request, the ILR updates the mapping information in the local cache and records the latest mapping information of the MN;

Step S303-7, the T-ASN sends a route request success response to the MN, and carries out subsequent session modification work;

step S303-8, after the access work is completed, MN sends new session establishment request to AME through T-ASN, and the data packet contains ID of new and old session;

step S303-9, after the AME receives the new session establishment request, the AME sends a session modification request to the SME for managing the old session, wherein the session modification request comprises the new session ID and the old session ID;

step S303-10, the SME managing the old session determines the ASN to be executed and relocates the ASN;

step S303-11, feeding back AME session modification response, wherein the data packet contains the information of the new session;

step S303-12, the SME sends a session modification request to the T-ASN, and the T-ASN feeds back a session modification response to the SME;

step S303-13, the T-ASN establishes a session specific to the T-ASN with the MN, and sends a new session establishment success response to the MN after the establishment is completed;

step S303-14, after the new session is established, the waiting timer stops, and the MN releases the session resource with the S-ASN.

A structure of a playback method for guaranteeing continuity of MEC services, said structure comprising a network layer structure and an application layer structure,

the network layer structure is divided into a Center DC (Data Center), a local DC, and an edge DC, and the application resources are offloaded to a position closer to the user, and the mobile terminal includes multiple types. Such as cell phones, autopilots, high speed trains, drones, etc. The playback network layer structure for guaranteeing the continuity of MEC service in the present invention is shown in fig. 1, and the application layer structure is shown in fig. 2, wherein the main network elements and the functional entities include:

Wherein the network layer structure comprises

An access service node ASN, which is an interface of an access network and a core network, is also an access connection point of a mobile terminal MN, is responsible for guaranteeing communication connection of the MN and the whole network, distributing a location address RID, registration, authentication, authorization and flow charging to the MN, caching the mapping relation of the UID/RID of the mobile terminal at a control layer, and is responsible for packaging and unpacking data packets in the network at a data layer,

the identity location register ILR (Identifier Locator Register), the ILR is responsible for maintaining and managing the latest UID/RID mapping relation of the mobile terminal, the initial registration flow, the RID inquiry of the wide area network communication opposite end,

session management network elements SME, which are responsible for session management, tunnel maintenance, route identification assignment and management, ASN selection, policy enforcement and QoS control and traffic charging, contain various types, such as SMF (Session Management Function ) in 5G networks, session management function of MME in 4G networks, etc.

An access and mobility management element AME, which is an access point of a terminal and a wireless core network and is responsible for performing registration, connection, reachability, mobility management, providing a session management information transmission channel for a mobile terminal and an SME, providing authentication and authentication functions for mobile terminal access, the network element including multiple types, such as AMF (Access and Mobility Management Function, i.e. access and mobility management functions) in a 5G network, and NAS access control functions in an MME in a 4G network.

Policy control network element PCE (Policy Control Network Element, i.e. policy control network element), which supports a unified policy framework governing network behaviour, provides policy rules to control plane enforcement, accesses subscription information related to policy formulation in a database, this network element contains multiple types, e.g. PCF (Policy Control Function, i.e. policy control function) in a 5G network, PCRF (Policy and Charging Rule Function, i.e. policy and charging control unit) in a 4G network.

Network capability open network element NEE (Network Exposure Network Element, i.e. network capability open network element), NEE provides an external disclosure of network function capabilities, external exposure can be divided into monitoring capabilities, provisioning capabilities, application and impact of traffic routing and policy/charging capabilities. This network element contains multiple types, e.g. NEF in 5G network (Network Exposure Function, i.e. network capability open), SCEF in 4G network (Service Capability Exposure Function, i.e. service capability open).

The application layer structure comprises the following components:

the mobile edge application ME APP, ME APP is an application instance running on the virtualized infrastructure, can interact with the mobile edge platform to obtain the mobile edge platform's server open capabilities,

The mobile edge platform MEP, the MEP is responsible for providing mobile edge services for the APP, comprising: service registration, service discovery, status monitoring, local breakout, DNS services, load balancer, firewall, and a series of wireless network capability services such as wireless network information services, location information services, bandwidth management services. In the collaboration mechanism of the distributed MEC system, it is possible to interconnect with different MEPs.

The radio network information service RNIS (Radio Network Information Service, i.e. radio network information service) provides services of wireless network related information for the ME APP, and the ME APP can acquire desired wireless network information, such as handover of the mobile terminal, by referring or subscribing.

The mobile edge platform manager MEPM is responsible for the functions of basic operation and maintenance of MEP, mobile edge service configuration, life cycle management of ME APP, application rules and demand management of ME APP and the like,

the mobile edge orchestrator MEO is an orchestration center of the MEC service, only one is deployed in China, is located in a center DC, macroscopically grasps all resources and capacities of the MEC platform, mainly comprises computing, storing, network resources, application program mirror resources in a virtual infrastructure manager, checking the integrity and authenticity of software packages, and then needs to measure the user resource requirements and available resources of each ME host, and selects the most suitable ME host for deployment.

The application function AF (Application Function), AF refers to various services in the application layer of the core network, and can be an application in the operator or an AF of a third party, such as a video server, etc. But may also be placed to the network edge, such as RNIS.

The data forwarding plane software DP (Data Plane), DP is responsible for executing the traffic rules issued by the MEP, handling traffic between the ME APP, ME services, DNS servers, proxy servers, 3GPP networks, other visited networks, local area networks and external networks.

Compared with the prior art, the invention has the following advantages that (1) a unified MEC service replay method is adopted to adapt to various continuity requirements of different scenes and services, the realization of exchanging lower service delay with lower service migration overhead is realized, and meanwhile, the MEC service replay process and network deployment are simplified.

(2) Session information between applications is bound with an identity of a mobile terminal, the identity is unique in the whole network, the influence of unified communication address change of the identity position on the service delay reliability of the terminal is reduced, the problem that some MEC applications do not support communication address change in the session process is solved, and meanwhile continuity of MEC service relocation when the mobile terminal moves across gateways is guaranteed.

(3) By adopting the network identification mode, the data packet forwarding does not involve a mobility anchor point, the access connection point and the APP after the cross-gateway movement are positioned at the same position close to the user, the routing roundabout is eliminated on the basis of ensuring the service continuity, unnecessary nodes and link time delay are reduced, and the forwarding reliability is improved.

(4) And when the network senses the position change of the application, the application platform is informed to carry out a preparation flow in advance, and a new application instance is rapidly distributed on the target MEP in a mode of cooperation of the application platform and the network. The method accelerates the perception of the application to the terminal behavior and the network state, realizes the position consistency of the access connection point and the target application, and realizes the application rapid migration and the service continuity guarantee of the MEC service in the mobile switching process.

(5) The unified network address is replaced by the identity and the route identity, the network forwarding does not involve a mobility anchor point, and the paradigm simplifies network architecture and network resources and supports simple and convenient access of multiple types of terminals.

(6) In the scheme, a network administrator distributes a unique User Identity (UID) for each mobile terminal device, an access service node distributes a Routing Identifier (RID) for the mobile terminal, UID/RID mapping information replaces a communication address with a unified original identity position, and a mobile edge platform binds an application session with the mobile terminal identity identifier UID.

(7) The mobile terminal, the network connection and the edge application are cooperatively migrated: when the mobile terminal is about to move across the gateway, the mobile terminal, the network connection and the edge application cooperate to carry out the migration across the gateway.

(8) Network layer and application layer architecture not involving mobility anchor edge networks: the edge network layer consists of a mobile terminal, an access service node and a data network, and the application layer structure consists of a client application, an access service node application, data plane software, a mobile edge platform, a radio network information service and a mobile edge application. The network does not involve mobility anchor points, eliminates routing detour, reduces unnecessary node delay and link delay, and improves the reliability of data packet forwarding. Mobile terminal online registration and session registration process, session is bound with terminal identity.

(9) In the scheme, the mobile terminal is switched across the gateway, and a network layer and an application layer inform a cooperative mechanism: the network senses that the terminal switching event occurs and notifies the application platform, the preparation flow is performed in advance, the terminal behavior and network state sensing of the application are quickened, and the position consistency of the access connection point and the target application is realized.

(10) When the mobile terminal is switched across the gateway, the application layer edge application migration signaling flow: the method for migrating the application layer edge application is uniform and efficient, simplifies the application migration flow and reduces the service migration time delay.

(11) When the mobile terminal generates cross-gateway switching, the network layer switching management and the application layer session updating signaling flow: the method for switching the network layer across the gateway efficiently reduces switching time.

(12) A flow for forwarding data packets between a mobile terminal and a wide area network application host machine: a packet forwarding flow is provided for mobile terminals and wide area network application hosts that does not involve mobility anchors.

(13) Deployment scheme and operation mechanism of network control plane ILR based on DHT-MAP: the control plane is composed of a plurality of ILRs, different autonomous domains are divided, and the ILRs of the domains store and query terminal mapping information based on the DHT-MAP.

Drawings

Fig. 1 is a schematic diagram of a network layer structure of a replay method for guaranteeing continuity of MEC service and a packet forwarding path in a handover process according to the present invention;

fig. 2 is a schematic diagram of an application layer structure and a switching process data transmission path of a playback method for guaranteeing continuity of MEC service according to the present invention;

FIG. 3 is a schematic diagram of a process for migrating an application at an edge of a cross-gateway switching application layer of a mobile terminal according to the present invention;

FIG. 4 is a schematic diagram of a flow of managing and updating application sessions of a mobile terminal in a cross-gateway switching network layer;

fig. 5 is a schematic diagram of a notification collaboration mechanism of a cross-gateway switching network layer and an application layer of a mobile terminal according to the present invention;

fig. 6 is a schematic diagram of a packet forwarding structure between a mobile terminal and a wan application host according to the present invention.

Detailed Description

In order to enhance the understanding of the present invention, the present embodiment will be described in detail with reference to the accompanying drawings.

Example 1: the network layer and application layer structure of the replay method, which guarantees continuity of MEC service, see figures 1-2,

the network layer structure of the replay method for guaranteeing continuity of MEC service in the invention is shown in figure 1, and the network layer is divided into a Center DC (Data Center), a local DC and an edge DC, so that application resources are unloaded to a position closer to a user. Mobile terminals include a variety of types such as cell phones, autopilots, high speed trains, drones, and the like. The playback network layer structure for guaranteeing the continuity of MEC service in the present invention is shown in fig. 1, and the application layer structure is shown in fig. 2, wherein the main network elements and the functional entities include:

Network layer:

the access service node ASN. The ASN is an interface between the access network and the core network and is also an access point for the mobile terminal MN. Is responsible for guaranteeing the communication connection between the MN and the whole network, distributing a location address RID to the MN, registering, authenticating, authorizing, charging flow and the like. The mapping relation of UID/RID of the mobile terminal is cached at the control layer. In the data plane, the ASN is responsible for encapsulating and decapsulating data packets in the network.

An identity location register ILR (Identifier Locator Register). The ILR is responsible for maintaining and managing the latest UID/RID mapping relation of the mobile terminal, the initial registration flow and RID inquiry of the wide area network communication opposite terminal.

Session management network element SME. The SME is responsible for session management, tunnel maintenance, route identification allocation and management, ASN selection, policy enforcement, qoS control, and traffic billing, among others. This network element contains various types, such as SMF (Session Management Function ) in 5G networks, session management function of MME in 4G networks, etc.

Access and mobility management network element AME. AME is an access point of a terminal and a wireless core network, and is responsible for performing registration, connection, reachability, and mobility management. A session management information transmission channel is provided for the mobile terminal and the SME, and an authentication and authorization function is provided for the access of the mobile terminal. This network element contains multiple types, such as AMF (Access and Mobility Management Function, i.e. access and mobility management function) in 5G networks, NAS access control function in MME in 4G networks.

Policy control network element PCE (Policy Control Network Element, i.e. policy control network element). The PCE supports a unified policy framework that governs network behavior, providing policy rules for control plane enforcement, accessing subscription information in the database related to policy formulation. This network element contains multiple types, e.g. PCFs (Policy Control Function, i.e. policy control functions) in 5G networks, PCRFs (Policy and Charging Rule Function, i.e. policy and charging control units) in 4G networks.

Network capability open network element NEE (Network Exposure Network Element, i.e. network capability open network element). NEE provides an external disclosure of network function capabilities. External exposure can be categorized into monitoring capabilities, provisioning capabilities, application and impact of traffic routing, and policy/charging capabilities. This network element contains multiple types, e.g. NEF in 5G network (Network Exposure Function, i.e. network capability open), SCEF in 4G network (Service Capability Exposure Function, i.e. service capability open).

Application layer:

the mobile edge applies ME APP. The ME APP is an application instance running on the virtualized infrastructure and can interact with the mobile edge platform to acquire the service opening capability of the mobile edge platform.

The edge platform MEP is moved. The MEP is responsible for providing mobile edge services for the APP, including: service registration, service discovery, status monitoring, local breakout, DNS services, load balancer, firewall, and a series of wireless network capability services such as wireless network information services, location information services, bandwidth management services. In the collaboration mechanism of the distributed MEC system, it is possible to interconnect with different MEPs.

The radio network information service RNIS (Radio Network Information Service ). The RNIS provides services of wireless network related information for the ME APP, and the ME APP may acquire desired wireless network information, such as handover of the mobile terminal, through a consulting or subscribing manner.

The mobile edge platform manager MEPM. The MEPM is responsible for the functions of basic operation and maintenance of MEP, mobile edge service configuration, life cycle management of ME APP, application rules and demand management of ME APP, and the like.

The edge orchestrator MEO is moved. MEOs are orchestration centers for MEC services, typically deployed only one nationally, at a central DC. The MEO macroscopically grasps all the resources and the capacity of the MEC platform, mainly comprises calculation, storage, network resources, application program mirror image resources in a virtual infrastructure manager, checking the integrity and the authenticity of a software package, and then needs to measure the resource requirements of users and the available resources of all ME hosts, and selects the most suitable ME host for deployment.

Application function AF (Application Function). The AF refers to various services in the application layer of the core network, and can be an application in an operator or an AF of a third party, such as a video server, and the like. But may also be placed to the network edge, such as RNIS.

Data forwarding plane software DP (Data Plane). The DP is responsible for executing the traffic rules issued by the MEP and handling traffic between the ME APP, ME services, DNS servers, proxy servers, 3GPP networks, other visited networks, local area networks and external networks.

Further, the invention introduces two kinds of identifiers for the User terminal, namely a User Identifier (UID) and a routing Identifier (Routing Identifier, RID). UIDs are unique identifiers assigned to mobile terminals by network administrators, representing the identity of nodes, which remain static and unchanged throughout the network. The method is mainly responsible for identifying the identity of the terminal during communication between the terminal and the application and between the terminal and the opposite communication terminal. The RID is used to indicate the current location of the end host and indicate the routing direction for the data traffic during the communication of the end. And the UID/RID mapping information is adopted to replace a communication address with uniform identity and position, and the mobile edge application platform binds the application session with the UID of the mobile terminal MN. The edge DN communicates through UID, the wide area network communicates through RID, the access network is separated from the core network, the connection point is ASN, and the network forwarding does not involve mobility anchor points.

In the MEC replay method provided by the invention, the unified MEC replay method is provided to cope with various continuity requirements of different scenes and services, and the continuity of the MEC service is ensured by the cooperative migration of the mobile terminal, the network connection and the edge application.

Example 2: a playback placement method for guaranteeing MEC service continuity, the method comprising the steps of: the method comprises the following steps:

The method comprises the following steps:

in step S1, the mobile terminal MN registers and session registration procedure:

taking mobile terminal MN as an example, the registration and session registration steps are:

step S101, mobile terminal MN is on line, and sends route request to ASN to which it belongs according to signal intensity, requesting access to ASN;

step S102, after receiving the route request of MN, ASN sends authentication and authorization request to AME in core network, AME carries out authentication service for terminal requesting access, judges whether access terminal is legal, AME is authorized for legal terminal;

Step S103, ASN distributes proper route identification RID for the authorized MN, and records UID/RID1 mapping information of the MN into a local cache;

step S104, ASN sends UID/RID1 mapping information update request to the ILR, and informs the ILR of the latest mapping information of the mobile terminal;

step S105, after receiving the updating of the mapping information, the ILR records the mapping information UID/RID1 of the mobile terminal into a local cache so as to enable a subsequent communication opposite terminal to initiate communication to the MN to inquire the routing information of the MN;

step S106, after the access work is completed, the ASN sends a route request success response to the MN. The MN client APP establishes a session to an edge APP in the edge data center, this session containing multiple types, e.g., PDU session in 5G network, PDN session in 4G network (Packet Data Network, i.e., packet data network). Firstly, MN sends a session establishment request to AME in a core network through ASN;

step S107, AME selects session management network element SME for the session which needs to be established by MN according to the RID information of MN;

step S108, the AME sends an MN session creation request to the selected SME, and the SME feeds back response information to the AME after receiving the request;

step S109, the AME and the SME cooperate to authenticate the session to be established, and judge whether the session to be established is legal or not, and the session is authorized to be legal;

Step S110, SME sends MN session creation request to ASN accessed by MN, ASN receives session request and feeds back response information to SME;

step S111, after receiving the response information, the SME forwards the session information to be created to the AME, and the AME feeds back the response information to the SME after receiving the response information;

in step S112, the ASN establishes an ASN-specific session with the mobile terminal through the access network RAN, and the establishment procedure includes sending session request response information to the mobile terminal MN.

After the session establishment between the MN and the ME APP is completed, the data packet forwarding path of the network layer is shown as a path a in the figure 1; the application layer data communication path is as path a in fig. 2.

In step S2, the mobile terminal MN generates a notification collaboration mechanism for switching network layers and application layers across gateways

The replay mechanism for guaranteeing MEC service continuity requires both application layer supporting application migration across gateways and fast migration of contexts and notification coordination mechanism between network layer and application layer.

The cooperation mechanism of mutual notification can be realized between the operator and the third party application through the information among the policy control network element PCE, the application function AF and the network capability opening network element NEE, as shown in figure 5, so that the third application can timely notify the application when sending the requirement to the network and the MN position and the network state change based on the service characteristics.

In step S201, the application layer subscribes to the network event notification. It can be realized in 3 ways by AF.

In the mode 1, the application layer transmits the request of the application to the network resource through the AF request message, so that the time delay and the bandwidth requirement required by the service are met by the network layer.

In mode 2, the application layer subscribes to event notification messages, e.g., a node makes a cross-gateway handover, to the network layer via AF/NEE to immediately notify AF when the network detects a subscribed event trigger.

And 3, the application layer adjusts the uplink and downlink and multi-homing strategy to realize the management of the access connection point ASN through the modification process of the AF initiation terminal data route.

step S203, the network layer PCE receives an AF subscription message, for example, the RNIS senses that the access connection point ASN of the session is changed, the DN access identifier DNAI (Data Network Access Identifier) is changed, etc., and the network layer will send a notification message to the application layer, including the changed target data network identifier DNAI, so that the application layer obtains the target ME host location to perform application migration, and ensures the consistency of the access node ASN and the target APP location;

AF initiates application cross-gateway migration, synchronizes application state information and session context information into ME APP in a target ME host, and during application migration, a network side forwards data packets with a source DN through a temporary tunnel, so that service is kept uninterrupted. After the application migration is completed, AF informs SME of the completion of the migration, SME initiates data transmission path update, and forwards client service in the mobile terminal from T-ASN to target mobile edge application T-APP, thereby realizing the mobility management of the cross-gateway seamless switching.

In step S3, the mobile terminal MN generates a cross-gateway handover application layer edge application migration procedure

In the following, an application layer edge application migration management flow in the mobile process of the mobile terminal MN is described by taking the case of cross-gateway handover as an example, as shown in fig. 3.

The mobile terminal MN is about to leave the service range of the source access service node S-ASN, signal detection is carried out, the signal of the new ASN is detected to be larger than the signal of the S-ASN, the difference of signal strength exceeds a certain threshold, the ASN is set as a target access service node T-ASN, a mobile application platform of the T-ASN is used as a target mobile application platform T-MEP, and the transfer of an application layer edge application ME APP is triggered.

The mobile terminal MN performs cross-gateway movement, and an application layer edge application ME APP migration flow is divided into 6 modules.

Module 1, MN is separated from S-ASN.

module 2, MN accesses T-ASN.

Step S303, MN network layer switching management and application session updating flow;

and a module 3 for updating the flow rule for the MN.

in step S305, the S-MEP queries the S-MEPM for a target host T-MEC host that enables the MN to receive the information, and the S-MEPM forwards the query to the MEO. The MEO determines a T-MEC host through a series of strategy modes such as an operator strategy, a mobile strategy, application requirements, application capacity, a mobile edge system state and the like, and forwards information to the S-MEP through the S-MEPM so that the S-MEP can be connected with the T-MEP. Meanwhile, S-APP and session context information which need to be migrated to the T-MEP in the S-MEP acquisition platform are acquired;

and a module 4, application migration management.

step S311, S-MEP captures the S-APP status information being serviced and acquires the completed session context information in step 305;

and a module 5, activating a new traffic routing rule.

Step S321, T-APP activates the traffic routing rule to T-MEP;

step S322, T-MEP activates the traffic routing rule;

step S325, S-MEP receives RNIS area change notification from S-RNIS;

And a module 6, terminating the source application.

The data transmission paths of the MN APP and the S-APP before the MN performs cross-gateway movement are shown as a path a in fig. 2, and the MN APP performs data transmission through the S-APP in the S-DP and the S-MEP; in the application migration process, the MN APP performs data transmission with the S-APP in the S-MEP through a temporary tunnel between the T-DP and the S-DP, and the path is shown as a path b in FIG. 2; after APP migration is completed, MN APP directly performs data transmission with T-APP in T-MEP through T-DP, as shown in path c in FIG. 2.

In step 303, the mobile terminal MN performs cross-gateway handover network layer handover management and application layer session update procedure

In the following, taking an example that the mobile terminal MN performs cross-gateway handover, a network layer handover management flow and an application layer session update in the mobile process of the mobile terminal are described, as shown in fig. 4.

The mobile terminal MN is about to leave the service range of the source access service node S-ASN, signal detection is carried out, the signal of the new ASN is detected to be larger than the signal of the S-ASN, the difference of the signal strength exceeds a certain threshold, the MN sets the ASN as a target access service node T-ASN, and network layer switching is triggered.

The network layer data packet forwarding path of the session before the MN performs cross-gateway movement is shown as a path a in fig. 1, and the MN performs data transmission with an edge DN through an S-ASN; in the switching process of the MN, namely before the timer is finished, the MN performs data transmission with a source DN through a temporary tunnel between a T-ASN and an S-ASN, and the path is shown as a path b in the figure 1; after the switching of the MN and the migration of the APP are completed, the timer is cut off, and the MN directly performs data transmission with the target DN through the T-ASN, as shown by a path c in fig. 1.

Example 3: data packet forwarding flow of mobile terminal MN and wide area network application platform

The mobile terminal MN not only communicates with the edge application host, but also needs to communicate with the application host in the wide area network, as shown in fig. 6, and the data message forwarding process of the mobile terminal initiating the communication is described below.

(1) The MN sends an original data packet to ASNm (ASN accessed by the MN) through RAN, and requests to communicate with a corresponding public network application host (hereinafter called a communication opposite terminal, corresponding Node, CN), wherein the source address in the original data packet is UIDm (identity of the MN), and the destination address is UIDc (identity of the CN);

(2) After ASNm receives the original data message sent by MN, inquiring the mapping information of CN in the local buffer according to the identity identification UIDC of CN in the data packet, obtaining the route identification RIDc of CN, if the mapping information of CN does not exist in the local buffer, executing (3), otherwise executing (5);

(3) ASNm sends an address query packet to ILRm in the local domain requesting to query mapping information of CN; after receiving the query data packet, the ILRm unpacks the data packet to obtain UIDC, and finds ILRc storing CN mapping information in a DHT (Distributed Hash Table ) mode;

(4) The ILRc receives the query information and feeds back mapping information UIDc/RIDc of CN in the local buffer memory to the ILRm, the ILRm is forwarded to ASNm, and the ASNm is stored in the local buffer memory for forwarding subsequent data packets;

(5) ASNm repackages the data packet, the source address is RIDm, the destination address is RIDc, and the data packet is sent to a wide area network router;

(6) The wide area network router forwards the data packet to ASNc according to the destination address RIDc;

(7) The ASNc receives the data packet and then unpacks the data packet to obtain the destination address UIDC of the original data packet, and the ASNc sends the original data packet to the opposite communication terminal CN according to the UIDC,

(8) ASNc matches the UIDM/RIDm mapping information with mapping information in the local buffer, if the matching is unsuccessful, the UIDM/RIDm mapping information is stored in the local buffer, so that the following CN can smoothly inquire the MN mapping information when sending a data packet to the MN.

When the mobile terminal is communicated with the public network application host, the data forwarding of the wide area network and the access network is separated, so that the state change of the terminal does not influence the network topology, and the change of the network topology does not impact the terminal. The terminal access mode is simple and does not consider the form of terminal equipment, such as a host, mobile equipment, an automatic driving automobile, an unmanned aerial vehicle, a satellite and the like, and the multi-system access of a user can be well supported.

In the data packet forwarding process, a stateful mobility anchor point is not involved, so that unnecessary node time delay caused by the mobility anchor point is eliminated, the transmission reliability is improved, and the network resources are saved.

In addition, the invention also provides a deployment scheme and an operation mechanism of the identity location register ILR. And a plurality of ILRs in the network, wherein each ILR is responsible for storing, updating and maintaining the latest UID/RID mapping information of the terminal. Different autonomous domains may be divided according to operators, enterprises, regions or countries. The control plane is composed of a plurality of autonomous domains, all ILRs in the domains form a domain routing table, and the domain routing table stores mapping information of all terminals in the domains; and meanwhile, each autonomous domain is provided with an inter-domain ILR, which is responsible for forwarding data packets with the inter-domain ILRs of other domains, and all inter-domain ILRs form an inter-domain routing table.

The autonomous domain in the invention adopts an operation mechanism based on DHT-MAP (Distributed Hash Table-MAP, namely distributed hash table-MAP) to store terminal mapping information and acquire mapping information of a communication opposite terminal node. Each ILR may perform a hash calculation on the UID to obtain a hash value, and the domain routing table stores virtual coordinate areas of respective domains, where the virtual coordinate areas are composed of domain hash values. All hash values constitute a virtual coordinate space.

The control plane operation mechanism will be described below by taking communication between the mobile terminal MN and the public network application host as an example.

When the MN accesses the ASNm, a routing request is sent to the ASNm, the ASNm forwards to the AME, the AME authenticates and authorizes the MN, the ASNm assigns an RIDm to a legitimate MN, and sends mapping information UIDm/RIDm of the MN to the ILR of the control plane of the home domain (the ILR in the home domain is not necessarily the ILRm storing the MN mapping information). Then, the ILR performs hash calculation on the UIDM to obtain a virtual coordinate point of the MN in the virtual coordinate space, and the virtual coordinate point is set as a point P. If the point P is in the autonomous domain, the autonomous domain ILR stores the mapping information into a domain routing table; if the P is not in the autonomous domain, the ILR forwards the P to the inter-domain ILR of the autonomous domain, the ILR sends the P to the inter-domain ILR of the autonomous domain which is closer to the virtual coordinate point, and the inter-domain ILR judges whether the P is in the virtual coordinate area of the autonomous domain, if so, the P is stored in an intra-domain routing table; if not forwarding to the inter-domain ILR closer to P until P is in the target autonomous domain. The storage was successful and fed back to ASNm. ASNm sends a route request success response to MN.

The ILR storing the mobile terminal MN mapping information is ILRm, and the ILR storing the public network application host mapping information is ILRc. ILRm is deployed in autonomous domain 1 and ILRc is deployed in autonomous domain 3. Wherein the distance between the virtual coordinate area of the autonomous domain 1 and the virtual coordinate area of the autonomous domain 2 is closer than the distance between the virtual coordinate area of the autonomous domain 1 and the virtual coordinate area of the autonomous domain 3.

When the MN initiates communication to the CN, firstly, the mapping information of the CN is queried through ASNm, and the mapping information of the CN is not recorded in the local cache in ASNm. ASNm then sends a query request packet to ILRm, which contains UIDc information. After receiving the query request data packet, the ILRm carries out hash calculation on the UIDC to obtain a hash value, a virtual coordinate point of the hash value is set as P, and whether the point P is located in a virtual coordinate area of the autonomous domain is judged. If the point P is located in the virtual coordinate area, inquiring a routing table in the domain, acquiring CN mapping information, and feeding back to ASNm; if not in the virtual coordinate area, the query request is forwarded to inter-domain ILR1, and ILR1 is forwarded to inter-domain ILR of the autonomous domain closer to point P in the virtual coordinate space, i.e., ILR2, through the inter-domain routing table. Receiving a query request data packet, judging whether the point P is in the virtual coordinate area by the ILR2, if so, searching an intra-domain routing table to feed back CN mapping information; if the inter-domain ILR and ILR3 in the autonomous domain closer to the point P are not forwarded, the mapping information of the CN is fed back to the ILRm by the intra-domain routing table until the point P is in the target autonomous domain. Next, the ILRm forwards the mapping information to ASNm, which stores the mapping information in the local cache, and the mapping information query process is completed. And then packaging the data packet, wherein the source address is RIDm, the destination address is RIDc, and the data packet is sent to a wide area network router, and the wide area network router routes the data packet to ASNc according to the RIDc. Finally, ASNc sends the data packet to the corresponding host CN according to UIDc.

It should be noted that the above-mentioned embodiments are not intended to limit the scope of the present invention, and equivalent changes or substitutions made on the basis of the above-mentioned technical solutions fall within the scope of the present invention as defined in the claims.

Claims

1. A replay method for guaranteeing continuity of MEC service, said method comprising the steps of:

2. The method for re-placement of MEC service continuity guarantee according to claim 1, characterized in that said step S1 is specifically as follows, mobile terminal MN registration and session registration procedure is specifically as follows:

step S105, after the access work is completed, ASN sends a successful response of the route request to MN, MN client Application (APP) establishes a session to edge APP in edge data center, the session includes multiple types such as communication data unit (PDU) session in 5G network, packet Data Network (PDN) session in 4G network, firstly MN sends a session establishment request to AME in core network through ASN;

3. The playback method for guaranteeing continuity of MEC service according to claim 1, characterized in that,

in step S2, the network layer and the application layer notify collaboration mechanism specifically includes:

in step S201, the application layer subscribes to the network event notification, is implemented in 3 ways by AF,

in step S203, the network layer PCE receives the AF subscription message, and the network layer sends a notification message to the application layer, including the changed target data network identifier DNAI, in order for the application layer to obtain the target ME host location to perform application migration, so as to ensure the consistency of the access node ASN and the target APP location.

4. The playback method for guaranteeing continuity of MEC service according to claim 1, characterized in that,

step S3 is a network layer switching management and application layer edge application migration flow, which comprises the following steps:

the module 1, mn is separate from the S-ASN,

step S302, enabling application mobility by the S-MEP, preparing for migration of the S-APP, wherein the steps include positioning the S-APP of the MN APP session and sorting session context data;

the module 2, mn accesses the T-ASN,

a module 3, updating the traffic rules for the MN,

the module 4, application migration management,

a module 5, activating a new traffic routing rule,

step S321, T-APP activates the traffic routing rule to T-MEP;

step S322, T-MEP activates the traffic routing rule;

step S325, S-MEP receives RNIS area change notification from S-RNIS;

A module 6, terminating the source application,

5. The playback method for ensuring MEC service continuity of claim 4, wherein step S303 is a network layer handover management procedure and an application session update procedure, and is specifically as follows:

6. The structure for realizing the playback method for guaranteeing continuity of MEC service according to any one of claims 1 to 5, characterized in that it comprises a network layer structure and an application layer structure,

the network layer structure is divided into a Center DC (Data Center), a local DC, and an edge DC, and the application resources are offloaded to a position closer to the user, and the mobile terminal includes multiple types.

7. The structure of playback method for guaranteeing continuity of MEC service according to claim 6, characterized in that the network layer structure comprises

session management network elements SME, SME being responsible for session management, tunnel maintenance, route identification allocation and management, ASN selection, policy enforcement and QoS control and traffic charging,

an access and mobility management network element AME, which is an access point of a terminal and a wireless core network and is responsible for executing registration, connection, accessibility and mobility management, providing a session management information transmission channel for the mobile terminal and the SME, providing authentication and authentication functions for the mobile terminal access,

A policy control network element PCE (Policy Control Network Element, i.e. a policy control network element), the PCE supporting a unified policy framework governing network behavior, providing policy rules for control plane enforcement, accessing subscription information related to policy formulation in a database,

network capability open network element NEE (Network Exposure Network Element, i.e. network capability open network element), NEE provides an external disclosure of network function capabilities, external exposure can be divided into monitoring capabilities, provisioning capabilities, application and impact of traffic routing and policy/charging capabilities.

8. The structure of a playback method for guaranteeing continuity of MEC service according to claim 6, characterized in that the application layer structure comprises:

the mobile edge application ME APP, ME APP is an application instance running on the virtualized infrastructure, interacts with the mobile edge platform to obtain the mobile edge platform's server open capabilities,

the mobile edge platform MEP, the MEP is responsible for providing mobile edge services for the APP, comprising: service registration, service discovery, status monitoring, local breakout, DNS service, load balancer, firewall, wireless network information service, location information service, bandwidth management service, and the like;

A Radio Network Information Service (RNIS) (Radio Network Information Service ), which provides a service of wireless network related information to the ME APP, which can acquire desired wireless network information by referring or subscribing,

the mobile edge orchestrator MEO, which is an orchestration center of the MEC service, is located in the center DC, and macroscopically grasps all resources and capacities of the MEC platform, mainly including computation, storage, network resources, application image resources in the virtual infrastructure manager, checking the integrity and authenticity of the software package, and then also needs to measure the user resource requirements and the available resources of each ME host, select the most suitable ME host for deployment,

the application function AF (Application Function), AF, refers to various services in the core network application layer,