APN issuing efficiency optimization method for eSIM dynamic switching

Abstract

The invention relates to the technical field of wireless communication networks, and discloses an eSIM dynamic switching-oriented APN (Access Point Name) issuing efficiency optimization method, which comprises the following steps that: an eSIM terminal acquires a capability label of each APN at a network side, analyzes a flow characteristic of an upper-layer application to extract a demand characteristic portrait of a current application at the same time, and further performs eSIM dynamic switching based on a matching result of the portrait and the label; and an appropriate APN is selected and connected autonomously. Through terminal application perception and APN capability identification capability, the APN selection process can dynamically respond to the instant demand of the application, it is ensured that the network access point and the application characteristic are highly matched from initial connection, a foundation is laid for follow-up fine adjustment based on the real network state and energy efficiency, and the method has the advantages of being high in practicability and easy to popularize. And the accuracy of wireless resource allocation and the terminal experience are obviously optimized.

Description

Technical Field

[0001] The present invention relates to a method for optimizing the APN distribution efficiency for eSIM dynamic switching, belonging to the technical field of wireless communication networks. Background Art

[0002] In the context of the rapid evolution of mobile communication networks, with the large-scale deployment of eSIM (Embedded Subscriber Identity Module), terminal devices can achieve dynamic switching of operators without replacing physical cards, which has become an important development direction of the new generation of communication architecture. However, the flexibility of eSIM dynamic switching also poses higher requirements for the network access process. Especially in the APN (Access Point Name) configuration and distribution link, how to achieve efficient and accurate matching and selection under changing network environments and application requirements has become a common technical challenge in the industry.

[0003] In the traditional mechanism, after an eSIM terminal completes the attachment or registration process, it usually obtains an APN from the network side according to a static preset or default policy for subsequent data connection. This APN is often bound to the user package or operator policy and lacks the ability to perceive the current application scenario. This single-assignment APN selection method is inadequate in the increasingly complex application environment. Especially in scenarios where a large number of diverse application traffic (such as high-definition video, low-latency interaction, IoT small data synchronization, etc.) runs concurrently, the traditional method is difficult to achieve the optimal matching of resource allocation, thereby affecting the experience stability of the terminal and the overall utilization efficiency of network resources.

[0004] Further observation reveals that in a typical multi-service concurrent scenario, the traditional technical solutions have the following deep-seated technical bottlenecks: 1. Lack of a real-time analysis mechanism based on the characteristics of the application traffic currently running on the terminal, resulting in the inability of APN selection to dynamically adapt to specific service requirements; 2. The representation method of APN service capabilities is not transparent, and the network side fails to provide ability labels for the terminal to refer to in a standardized form, restricting the refined judgment ability of the terminal side; 3. Even if there are multiple potential optional APNs, it is difficult for the terminal to accurately evaluate their response performance before establishing a connection, so it is impossible to effectively avoid access points with high latency or path congestion, resulting in uncertainty in the initial connection experience. Although some operators try to improve through policy distribution or preset APN classification methods, these methods generally fail to achieve linkage updates with the actual application status of the terminal and also fail to fully perceive the immediate state of the network path before connection establishment. Therefore, it is still difficult to fundamentally solve the above problems. Therefore, how to implement a mechanism that supports eSIM terminals to make dynamic judgments based on application portraits and network capability information and efficiently select the best among multiple APN candidate paths to optimize the APN distribution efficiency and connection experience has become the technical problem to be solved by the present invention. Summary of the Invention

[0005] The present invention provides a method for optimizing the APN delivery efficiency for eSIM dynamic switching, and its main purpose is to solve the problem that eSIM terminals lack a dynamic matching mechanism based on application requirements and network capabilities in a multi-service environment, making it difficult to achieve accurate and efficient APN selection.

[0006] To achieve the above object, a method for optimizing the APN delivery efficiency for eSIM dynamic switching provided by the present invention is characterized in that the method includes the following steps: Step 1, the eSIM terminal obtains APN capability tags provided by the network side, and the APN capability tags describe the service capability characteristics of each available access point name (APN). Step 2, the eSIM terminal extracts the demand feature portrait of the currently running application by analyzing the traffic statistical characteristics generated by the upper-layer application within a determined monitoring time window. The traffic statistical characteristics include one or more of the average packet size, the uplink and downlink traffic ratio, and the packet sending frequency per unit time. Step 3, the eSIM terminal performs a matching calculation based on the extracted demand feature portrait and the obtained APN capability tags to select one or more candidate APNs that match the demand feature portrait; and the eSIM terminal establishes a data connection through a final APN determined from the one or more candidate APNs.

[0007] Preferably, the APN capability tags are defined by the network operator and configured on the network side, and are broadcast to the eSIM terminal through the cellular network system information, or are sent to the eSIM terminal through the extended information carried when the eSIM terminal executes the attachment process, the tracking area update (TAU) process, or the routing area update (RAU) process, or are sent together when the eSIM configuration file is downloaded and updated.

[0008] Preferably, the step of the eSIM terminal extracting the demand feature portrait of the currently running application by analyzing the traffic statistical characteristics generated by the upper-layer application within a determined monitoring time window is specifically as follows: Under the condition of not performing deep packet detection, the application type sniffing and demand abstraction module in the eSIM terminal monitors and statistics the total uplink and downlink traffic, the total number of packets, the average packet size of uplink data transmission, and the average packet size of downlink data transmission within the determined monitoring time window; calculates the uplink and downlink traffic ratio and the average packet sending frequency per unit time based on the statistical results; and compares the calculated uplink and downlink traffic ratio, the average packet sending frequency per unit time, and the average packet size of uplink and downlink data transmission with the characteristic parameter thresholds corresponding to different application demand feature portrait templates stored in the eSIM terminal to determine the demand feature portrait that matches the currently running application.

[0009] Preferably, after the eSIM terminal selects one or more candidate APNs that match the demand feature profile and before establishing a data connection through the final APN, the following steps are further included: Step 1, if it is determined that there are at least two candidate APNs, the eSIM terminal initiates an initial access signaling interaction for each of the at least two candidate APNs, and the initial access signaling interaction aims to obtain the instantaneous response status of its corresponding network path; Step 2, the eSIM terminal captures and compares the micro-temporal delays of each initial access signaling interaction from the time of sending to receiving the first explicit response signaling from the network side. ; and the eSIM terminal selects the candidate APN with the smallest micro-temporal delay value as the final APN, where the micro-temporal delay indicates the response agility of the corresponding candidate APN network path.

[0010] Preferably, the initial access signaling interaction is a PDU session establishment request NAS message that does not contain complete user plane parameters, or is the initial signaling for the selection process of different core network data network names (DNNs) when establishing a connection at the RRC layer.

[0011] Preferably, after the eSIM terminal establishes a data connection through the final APN, the following steps are further included: Step 1, the application type sniffing and demand abstraction module in the eSIM terminal continuously monitors the application service quality (QoS) metrics of the current data connection, and the QoS metrics include the throughput rate perceived by the eSIM terminal or the round-trip time (RTT) estimated through application layer feedback information; Step 2, if the monitored QoS metric is lower than the QoS expected baseline associated with the current demand feature profile by a predetermined deviation threshold and there are alternative APNs in the local cache whose APN capability tags match the demand feature profile, the eSIM terminal actively attempts to switch to one of the alternative APNs.

[0012] Preferably, after the eSIM terminal establishes a data connection through the final APN, the following steps are further included: Step 1, the eSIM terminal is based on the APN capability tag of the final APN and the previously extracted demand feature profile of the currently running application, this dual context information; Step 2, from the energy-saving policy knowledge base preset in the eSIM terminal, query and determine a set of energy-saving communication parameter configurations that match the current dual context information combination, and the energy-saving policy knowledge base defines the energy-saving communication parameter adjustment rules corresponding to different context combinations; Step 3, the communication module of the eSIM terminal adjusts at least one of its current radio resource control (RRC) parameters, discontinuous reception (DRX) cycle parameters, or power saving mode (PSM) configuration parameters according to the determined energy-saving communication parameter configuration to optimize the energy consumption when performing data communication through the final APN.

[0013] Preferably, the energy-saving communication parameter adjustment rules defined in the energy-saving strategy knowledge base include: if the APN capability label is energy-saving connection and the application demand feature profile is small data intermittent type, configure the communication module to use a longer DRX cycle and enable PSM; or if the APN capability label is low-latency optimization and the application demand feature profile changes to background data synchronization, configure the communication module to extend the DRX cycle.

[0014] Preferably, the APN capability label is a set of standardized descriptors used to characterize the core service characteristics of the APN, and the core service characteristics are selected from one or more of the following: low-latency optimization, uplink bandwidth priority, downlink stable transmission, energy-saving connection, and basic Best Effort service.

[0015] Compared with the problems in the background art, the beneficial effects of the present invention are as follows: 1. This method enables the eSIM terminal to form a dynamic application demand feature profile based on the instant analysis of the actual traffic characteristics of the currently running application, and actively obtain the standardized capability labels provided by the network side for each APN. By matching and calculating these two - that is, the instant application demand on the terminal side and the APN service characteristics declared by the network side - the terminal can autonomously select one or more candidate APNs that best match the current application demand; this mechanism ensures that the selection of APNs is no longer statically preset or blindly allocated, but application-oriented from the beginning of connection establishment, laying a suitable access foundation for upper-layer applications, thereby improving the matching degree between network resources and application demands.

[0016] 2. After initially screening candidate APNs through application demands and APN capability labels, this method further introduces a refined evaluation mechanism for the instantaneous state of the network path. Specifically, the eSIM terminal initiates a minimal initial access signaling interaction for each candidate APN and captures the micro-timing delay generated by the first clear response of the network side to this signaling. By comparing these delays, the terminal can identify the network path with the most agile current response and preferentially select the APN corresponding to this path to establish the final data connection; this step goes beyond the consideration of the static service capabilities of APNs and incorporates the instant activity of the network path into the decision-making, so that the selection of APNs not only matches the functional requirements of the application but also adapts to the current real bearer situation of the network.

[0017] 3. After the data connection is established, this method can utilize the ability tags of the selected APN and the previously extracted current application requirement feature profile, these two pieces of context information. Based on this combined information, the eSIM terminal can query and determine a set of energy-saving communication parameter configurations that match it from the pre-set energy-saving strategy knowledge base in itself, and accordingly adjust its own radio resource control parameters, discontinuous reception period, power consumption saving mode and other configurations; this design makes the energy-saving behavior of the terminal no longer isolated and universal, but can be refined and dynamically adapted according to the current application scenario and the characteristics of the accessed APN, so as to effectively optimize the energy consumption of the terminal while ensuring the application experience.

[0018] 4. This method constructs a continuously optimized closed-loop system. After establishing a data connection through the final APN, the eSIM terminal will continue to monitor the application service quality indicators passing through the current data connection. If the monitored service quality indicators are lower than the expected baseline associated with the current requirement feature profile, and there are other alternative APNs in the local cache that match this requirement feature profile, the terminal can actively attempt to switch to one of the alternative APNs; this mechanism combines the intelligent selection at the initial connection with the continuous quality perception and adaptive adjustment during the connection process, realizing the ability of the eSIM terminal to dynamically maintain and improve the service quality in the face of network fluctuations or application requirement changes, and enhancing the resilience of the connection and the stability of the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a performance comparison diagram between the present invention and traditional static selection in video stream and IoT application scenarios; Figure 2 It is a flowchart of access optimization of the eSIM terminal of the present invention based on the matching of application requirement feature profile and APN ability tags; Figure 3 It is a flowchart of intelligent matching and path evaluation optimization of the eSIM terminal of the present invention based on ability tags and feature profiles.

[0020] The implementation, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The present invention proposes an optimization method for APN distribution efficiency for eSIM dynamic switching. Its core objective is to achieve an intelligent access point selection mechanism between the terminal and the network side in a changing application environment, thereby improving access accuracy, shortening connection latency, and enhancing resource matching and service continuity after connection. This technical solution uses a three-in-one collaborative mechanism of terminal application traffic awareness + network capability tags + multi-APN path evaluation to construct a complete APN selection closed-loop path, which has high engineering feasibility; specifically, the eSIM terminal first obtains the APN capability tags provided by the network side. This tag describes the service capability characteristics of each APN in a standardized form and constructs a feature portrait of the current application requirements by analyzing the application traffic characteristics locally; then, the terminal selects one or more candidate APNs based on the matching result of the portrait and the APN capability tags; on this basis, further evaluate the immediate responsiveness of each candidate path, determine the finally accessed APN with the optimal delay path, and establish a data connection accordingly. This method defines and uses this structured description of APN capability tags as the standard interface for the network side to open its capabilities to the terminal. This tag is formulated by the operator and usually contains the following dimensional information, such as whether it optimizes low latency, whether it supports uplink bandwidth priority, whether it adapts to stable downlink transmission, whether it is suitable for energy-saving connections, etc.; each characteristic can be encoded using a boolean or hierarchical identifier and is sent to the terminal through various paths such as cellular system broadcasts, attachment signaling, and eSIM configuration updates to achieve wide compatibility and dynamic update capabilities. The corresponding terminal-side processing mechanism is implemented by an application type sniffing and requirement abstraction module embedded in the eSIM terminal system. This module does not require deep packet inspection (DPI), but instead models application behavior based on the structural statistical indicators of data packets: including the total uplink and downlink traffic per unit time, average packet size, packet sending frequency, etc. Key parameters are calculated through sliding statistics within a time window and compared with multiple preset application portrait templates to identify the feature portrait corresponding to the currently active application; among them, energy-saving connection means that this APN has the ability to support the terminal to enable energy-saving parameters such as DRX long cycle or power saving mode (PSM).

[0023] In the matching phase, the terminal compares and calculates the recognized demand feature profile with the received APN capability tags. Specifically, it can be carried out through a threshold scoring mechanism. For example, if the demand feature profile shows high-frequency small data packets and a high uplink ratio, it is more inclined to select an APN marked as uplink bandwidth priority in the tags. This matching mechanism is essentially a multi-dimensional feature fitting process, which supports screening out several candidate paths with the most suitable functions from several APNs. Further, to avoid problems such as path unavailability or congestion caused by relying solely on static matching, the present invention proposes a micro-temporal delay evaluation mechanism. That is, among multiple candidate APNs, the eSIM terminal can parallelly initiate extremely simple access request signaling, such as sending an initial NAS message for PDU session establishment or an RRC connection request without complete user plane information, and then capture the time delay from sending to the network side response. , and use the APN corresponding to the smallest one as the final connection object. This step effectively eliminates potential high-delay paths and realizes the perception-based optimization of the network's immediate state. If the terminal detects a decrease in QoS (Quality of Service) after successful access, and there are still other APN capability tags in the local cache that match the current demand feature profile, the fast switching process can be executed again. The QoS metrics can include throughput, RTT, etc. The judgment basis is whether the current observed value deviates from the QoS expected baseline set by the profile by a certain threshold. This mechanism ensures the dynamic stability during the connection persistence phase. In addition, an energy-saving communication strategy mechanism is introduced: after the terminal establishes a connection, based on the combined information of the capability tags of the finally selected APN and the current application profile, it accesses the preset energy-saving strategy knowledge base to select the most suitable communication parameter configuration, including RRC parameters, DRX cycle, or PSM (Power Saving Mode), etc., and adjusts the operation parameters of the communication module accordingly. This mechanism realizes the real-time trade-off between communication efficiency and energy efficiency, reflecting the engineering considerations for IoT and small data sensing scenarios. In terms of parameters, for key indicators such as the ratio of uplink and downlink traffic, average packet sending frequency, and packet size, the following calculation formulas are used: uplink-downlink ratio = , packet sending frequency = , average packet length = , where and are the total number of bytes of uplink and downlink within the time window respectively, is the number of data packets, is the monitoring window duration; among which, the QoS expected baseline is derived from the preset portrait parameter library in the terminal, and is inductively set according to the typical service quality expectations corresponding to different types of applications. For example, for video applications, its QoS expected baseline can be set as the throughput rate not being lower than the specified threshold, while IoT-type applications mainly focus on the stability of the RTT value. This baseline serves as a reference standard for the terminal to determine quality fluctuations during operation, supports making intelligent adjustment decisions during dynamic connection maintenance; and during the process of extracting the portrait of application demand characteristics, only based on the structural statistical characteristics of the network layer / transport layer, such as uplink and downlink traffic, average packet length, and packet sending frequency, for modeling, without involving deep packet inspection DPI, nor parsing or recording any application content data or user identity information, fundamentally avoiding access to user privacy content, and, all data statistical processing executed by the application type sniffing and demand abstraction module on the terminal side is completed locally, without involving the transmission of raw traffic data to the network side or third-party servers, and to ensure data security, the following strategies are adopted in the implementation of the local module, such as data minimization: only retain the necessary statistics within the current time window, without storing historical detail data; local encapsulation processing: all calculations are completed locally on the terminal device to avoid the risk of data leakage; sandbox isolation mechanism: the application identification module and the user service application process run in an isolated environment to prevent unauthorized access; regular data clearing: the statistical data is only used for immediate feature matching purposes and is cleared after use; an optional user authorization mechanism, such as when implementing the product: the user can view and decide whether to enable the application feature recognition function in the settings, all of which belong to the extended implementation methods known to those of ordinary skill in the art.

[0024] Embodiment 1: This embodiment discloses an access point selection method applicable to the eSIM dynamic switching scenario. Its core lies in the application perception and APN capability matching engine integrated inside the eSIM terminal, collaborating with the timing-reduced detection mechanism and the context-driven energy-saving control module to implement a complete APN selection process covering application identification, network capability identification, path optimization, and energy efficiency strategy adjustment. The typical application scenario faced by this process is: the eSIM terminal concurrently runs multiple types of applications in the mobile communication network, and the network side simultaneously supports multiple function-heterogeneous APN configurations. The terminal needs to establish a fast, accurate, and continuously optimizable data connection based on the current actual usage status.

[0025] In this embodiment, the eSIM terminal first activates the application type sniffing and requirement abstraction module inside it. This module sets a fixed monitoring time window (e.g., ten seconds), and continuously collects the packet feature information of the IP layer within this window, including: the total amount of data transmitted in the upstream and downstream directions, the total number of packets, the average packet sending frequency per unit time, and the average packet size in the upstream and downstream transmission directions. This module does not rely on deep packet inspection, but realizes the modeling of the data flow behavior based on the structural statistical features independent of the transmission protocol. After the data collection is completed, the system processes the above features in real time to form a set of three - element feature indicators: namely, the packet sending frequency per unit time, the upstream - downstream data transmission ratio, and the average packet length in the upstream and downstream directions. These three indicators constitute the traffic feature portrait of the currently active application, and are compared with the typical application portrait templates preset in the internal database of the terminal. For example, if the portrait of the video - playing application set in the template shows that the downstream data accounts for a high proportion, the average packet length is relatively large, and the packet sending frequency is medium, then when all the above three indicators fall within the parameter tolerance range set by the template, the system determines that the portrait match is established, and further identifies the type of the currently running application. At the same time, the terminal obtains multiple APN capability tags defined by the network side through any one of the following three methods: 1. Receive the APN capability tags from the system broadcast information during the attachment process or registration process; 2. Parse and obtain the capability tag content of each APN from the extended information field carried during the tracking area update or routing area update process; 3. Obtain the APN tag update data together with the configuration file during the eSIM configuration file update. The APN capability tags are formulated by the network operator and uniformly adopt a structured description format to represent whether the access point has one or more service capabilities such as low - latency optimization, upstream bandwidth priority, stable downstream transmission, and energy - saving connection.

[0026] Next, the eSIM terminal activates the APN capability adaptation module. Based on the previously extracted application demand feature profile, this module performs fitting calculations and priority sorting on each of the obtained multiple APN capability tags one by one. For example, if the current application demand feature profile shows a high-frequency uplink small data packet type, the APN with the uplink bandwidth priority capability identifier will receive a higher score; if the current profile is background intermittent data synchronization, the system will give priority to the APN with energy-saving connection capabilities. After being scored and sorted by this module, the top two APNs are selected as candidate access points. To further avoid the problem of poor response performance in the selected candidate APN paths, the system then initiates the response agility assessment sub-process; in this process, the terminal does not perform a complete PDU session establishment, but instead sends an initial access request signaling to each candidate APN respectively, such as a connection request message without complete user plane parameters. Subsequently, the terminal measures the time difference from when the signaling is sent to when the network side response is received, that is, the micro-timing delay value, and determines the candidate APN with the smallest delay as the final access object, and then establishes a formal data connection through this APN; after the data connection is completed, the terminal enters the running state service quality perception and connection stability maintenance mechanism. Under this mechanism, the application type sniffing module continuously monitors the service quality indicators of the application carried by the connection, including throughput and round-trip time. The system compares and judges the above monitoring indicators with the service quality expected baseline bound to the application demand feature profile; if the detected indicators are lower than the baseline and exceed the set deviation threshold, and there are other optional APN tags in the terminal local cache that match the profile, the fast switching process is immediately initiated to re-select and connect to another APN to maintain the stability of the overall service quality.

[0027] In addition, to optimize the energy efficiency during the terminal communication process, the system further introduces an energy-saving strategy knowledge base and context joint configuration module. This module takes the currently connected APN capability tag and the currently identified application demand feature profile as joint context inputs, and retrieves the most applicable communication parameter configuration scheme from the pre-set energy-saving strategy knowledge base inside the terminal; if the currently accessed APN has energy-saving connection capabilities and the application demand feature profile is background synchronization type, the system will find that the recommended configuration is to extend the discontinuous reception period and enable the power consumption saving mode. The terminal communication module adjusts the radio resource control parameters, discontinuous reception period duration, or the activation conditions of the power consumption saving mode accordingly to achieve energy consumption control optimization under the premise of service quality guarantee, especially applicable to scenarios such as low-frequency communication and small data sensing.

[0028] Example 2: Against the backdrop of the increasingly complex current mobile communication network and the widespread deployment of eSIM terminals, terminal devices are faced with the challenge of efficiently and accurately selecting an access point name (APN) in diverse application scenarios. Traditional APN selection mechanisms often rely on static presets or operator policies and lack the ability to perceive the immediate needs of upper-layer applications on the terminal and the instantaneous state of the network. This results in insufficient matching between APN selection and application characteristics in multi-service concurrent scenarios, thereby affecting the user experience and the utilization efficiency of network resources. For example, high-definition video streams have high requirements for bandwidth and latency, while Internet of Things (IoT) devices typically require low power consumption and intermittent connections. This experiment aims to verify the APN dynamic switching optimization method proposed in the present invention by constructing a test platform that simulates real application scenarios, that is, by extracting the application demand feature portraits on the eSIM terminal side, obtaining and intelligently matching the APN capability tags on the network side, and an optimal path selection mechanism based on micro-timing delay evaluation, and how it can significantly improve the APN distribution efficiency, optimize connection agility, and ultimately improve the terminal user experience and energy efficiency.

[0029] In this experiment, we built a comprehensive test platform consisting of an eSIM terminal simulator, a core network function simulator (including partial functions of AMF, SMF, UPF, and UDM), and multiple simulated base stations. This platform can simulate a network environment with multiple APN configurations and support the eSIM terminal to obtain dynamic capability tags and signaling interactions. First, we used an eSIM terminal simulator deeply customized based on mainstream mobile operating systems. This simulator is built with an application type sniffing and demand abstraction module, an APN capability adaptation module, a response agility evaluation module, and an energy-saving policy knowledge base and context joint configuration module. The application type sniffing and demand abstraction module sets a configurable monitoring time window, with a typical value of 5 seconds. Without performing deep packet inspection (DPI), it constructs an application demand feature portrait by statistically analyzing the structural indicators of transport layer data packets in real time. These indicators include: the total uplink and downlink traffic ( , ) the total number of bytes transmitted in the uplink and downlink within the monitoring window; the total number of data packets ( ) the total number of data packets transmitted within the monitoring window; the packet sending frequency: / (monitoring window duration); the average packet length / ; Through these statistical features, the simulator can dynamically identify and match three typical application demand feature portrait templates: the video stream type is typically characterized by a high proportion of downlink traffic ( much greater than ), with a relatively large average packet length and a moderately high packet transmission frequency; the IoT intermittent type is typically characterized by small data packets, a low or intermittent packet transmission frequency, and relatively small uplink and downlink traffic; the interactive type (such as online games / instant messaging) is typically characterized by high-frequency small data packets, relatively balanced uplink and downlink traffic, and sensitivity to latency; the APN capability adaptation module is responsible for receiving and parsing the APN capability tags sent by the network side, and based on the current application demand feature profile, performing priority sorting on available APNs according to a preset matching algorithm (using a weighted scoring mechanism); when there are multiple candidate APNs, the response agility evaluation module measures the micro-timing delay ( ), and selects the APN with the minimum delay; the energy-saving strategy knowledge base and context joint configuration module stores the energy-saving communication parameter configuration rules under different combinations of APN capability tags and application demand feature profiles, and is used to dynamically adjust the radio resource control (RRC) parameters, discontinuous reception (DRX) cycle parameters, or power saving mode (PSM) configuration of the terminal.

[0030] We configured three virtual APNs in the core network function simulator, defined standardized capability tags for them, and sent them to the eSIM terminal simulator through the simulated cellular network system information broadcast mechanism: the APN-A capability tag is low-latency optimization, with uplink bandwidth priority; the APN-B capability tag is energy-saving connection, with stable downlink transmission; the APN-C capability tag is basic Best Effort service; this experiment mainly focuses on the following performance indicators: the APN selection accuracy is to evaluate the matching degree between the APN selected by the terminal and the actual application demand feature profile; the connection establishment latency is the end-to-end latency from the terminal initiating an APN connection request to the successful establishment of the data path, with a focus on the optimization effect of the micro-timing delay ( ); the energy efficiency performance is the average power consumption of the terminal under different application scenarios; the quality of service (QoS) maintenance ability is the continuous monitoring and adaptive switching ability of the terminal for throughput and round-trip time (RTT) after the connection is established. All latency measurements use high-precision timestamp synchronization, and the average value is taken through repeated measurements to eliminate accidental errors. The power consumption measurement is performed through real-time sampling by a high-precision current sensor integrated on the terminal simulator.

[0031] This experiment designed three groups of typical scenarios. Each group of scenarios was repeated 20 times in a controlled environment, and the average values of various key indicators were recorded. Video stream application connection: The application background was to simulate users watching high-definition online videos on an eSIM terminal. This application had high requirements for downlink bandwidth and latency. Experimental steps: The eSIM terminal simulator was started, and the video stream application was started. The application type sniffing and requirement abstraction module monitored the traffic characteristics of the video stream and extracted the application requirement feature portrait. The APN capability adaptation module obtained the APN capability tags sent from the network side, and performed matching and priority ranking. The response agility evaluation module conducted micro-timing delay tests on the top two candidate APNs. The terminal selected the optimal APN and established a data connection to start video playback. Continuously monitor QoS indicators (throughput, RTT). Compare the performance differences between traditional static APN selection (default is APN-C) and the method of the present invention. Observation and data recording: After the video stream application was started, the application type sniffing and requirement abstraction module identified the following traffic characteristics: The total downlink traffic was significantly higher than the uplink (average / ratio was about 9.5:1), the average packet length was about 1450 bytes, and the packet sending frequency was about 80 pps (packets per second). These characteristics highly matched the preset video stream type portrait. In the matching stage, the APN capability adaptation module, according to the matching algorithm, rated APN-B (stable downlink transmission) as the highest priority, followed by APN-A (low latency optimization), and APN-C the lowest. In the micro-timing delay evaluation, the average of APN-B was 28.1 ms, and the average of APN-A was 32.5 ms. Since APN-B performed excellently in both capability matching degree and response agility, the terminal finally selected APN-B to establish a data connection. The performance comparison data between the method of the present invention and traditional static APN selection in the video stream application connection scenario are shown in Table 1 in detail.

[0032] Table 1: Performance comparison of connection establishment in Scenario 1.

[0033]

[0034] The method of the present invention, through the intelligent matching of the application portrait and APN capability tags and micro-timing delay evaluation, reduced the connection establishment latency by about 50%, increased the initial throughput by 126%, and reduced the RTT by 54%. This indicates that the dynamic selection mechanism can significantly optimize the connection performance in the video stream scenario.

[0035] IoT Intermittent Application Connection: The application scenario is to simulate the periodic uploading of small data packets by smart city sensors (such as environmental monitoring nodes). This application is sensitive to power consumption, has relatively loose requirements for latency, but needs to ensure reliable data transmission; Test steps: Start the eSIM terminal emulator and start the IoT data reporting application (report once every 1 minute, with each data volume being about 100 bytes); The application type sniffing and requirement abstraction module monitors the traffic characteristics and extracts the application requirement feature portrait; The APN capability adaptation module performs matching and priority sorting; The terminal selects the optimal APN and establishes a data connection; Continuously monitor the power consumption of the terminal; Compare the energy efficiency performance of the traditional static APN selection and the method of the present invention; Observation and data recording: After the IoT application is started, the application type sniffing and requirement abstraction module identifies the following traffic characteristics: small data packets (average packet length is about 100 bytes), extremely low and intermittent packet sending frequency, and very small total uplink and downlink traffic. These characteristics highly match the preset IoT intermittent portrait; In the matching stage, according to the matching algorithm, the APN-B (energy-saving connection) is rated as the highest priority by the APN capability adaptation module. The terminal finally selects APN-B to establish a data connection. After the connection is established, the energy-saving strategy knowledge base and context joint configuration module adjust the DRX cycle of the communication module to a longer value (for example, extended from the default 320ms to 2560ms) according to the energy-saving connection capability label of APN-B and the IoT intermittent application portrait, and enables PSM. Among them, the comparison results of the energy efficiency performance of the IoT intermittent application connection are shown in Table 2.

[0036] Table 2: Comparison of energy efficiency performance in Scenario 2.

[0037]

[0038] In the IoT scenario, the method of the present invention reduces the average power consumption of the terminal by about 75% through intelligent matching and energy-saving strategy adjustment, while maintaining the reliability of data transmission. This fully verifies the significant effect of this method in optimizing the energy consumption of the terminal, which is crucial for battery-powered IoT devices. The connection establishment latency is also optimized synchronously.

[0039] Multi-service Concurrency and QoS Adaptive Maintenance: The application background is to simulate a terminal running an online game (interactive) and a background data synchronization application (IoT intermittent) simultaneously. The online game has extremely high requirements for latency and response agility, while the background data synchronization demands stable transmission and energy efficiency. This scenario focuses on verifying the initial selection of APN and the adaptive switching ability during subsequent QoS degradation under multi-service conditions; Experimental steps: The eSIM terminal emulator starts the online game and the background data synchronization application simultaneously; The application type sniffing and requirement abstraction module identifies the currently active traffic characteristics (mainly dominated by online game traffic at this time) and extracts the requirement feature profile of the interactive application; The APN capability adaptation module and the response agility evaluation module cooperate to select the optimal APN and establish an initial data connection; Simulate sudden network congestion on the network side (for example, by introducing an additional 100 ms end-to-end latency), resulting in the degradation of the QoS of the current connection; The application type sniffing and requirement abstraction module continuously monitors the QoS metrics. If the metrics are lower than the expected baseline and reach a predetermined deviation threshold (set to an RTT deviation exceeding 20 ms in this experiment), and there is a matching alternative APN in the local cache, then trigger the active switching process; Record the QoS changes and the switching process; Observation and data recording: At the initial stage of multi-service concurrency, the online game traffic characteristics (high-frequency small data packets, balanced uplink and downlink traffic, latency-sensitive) are identified as the main application profile. After matching and evaluation, APN-A (low-latency optimization, uplink bandwidth priority) is selected as the optimal one, with a micro-timing delay of 26.7 ms. The terminal successfully connects to APN-A, and the initial average RTT is 35.1 ms, and the online game experience is smooth; At the 5th minute of the experiment, we simulate the introduction of additional latency to the APN-A path on the network side, resulting in a rapid increase in its RTT to an average of 75.3 ms. The QoS monitoring module of the eSIM terminal identifies that the RTT has deviated from the QoS expected baseline (average RTT not higher than 45 ms) set for the interactive application profile and exceeds the 20 ms deviation threshold. At this time, there is an alternative APN (APN-B) in the terminal's local cache. Although its capability label is more inclined to energy conservation, its low-latency performance is sub-optimal and not affected by the current congestion. The terminal actively initiates a switch and completes the switch to APN-B within about 2 seconds. After the switch, the RTT of the online game resumes to an average of 40.5 ms, and the service fluency is effectively maintained. Among them, the performance data of QoS adaptive maintenance in the multi-service concurrency scenario are recorded in detail in Table 3.

[0040] Table 3: QoS Adaptive Maintenance Performance in Scenario Three.

[0041]

[0042] This scenario verifies the robustness of the method of the present invention in complex multi-service scenarios. It can not only accurately select the initial APN according to the dominant application type, but also quickly identify and actively switch to the alternative APN when the network state deteriorates and the QoS degrades, thus effectively maintaining the continuity and stability of the user experience.

[0043] The experimental data of this series fully and powerfully prove the practical effectiveness and significant advantages of the APN distribution efficiency optimization method proposed by the present invention for eSIM dynamic switching. The accuracy of APN selection is greatly improved: through the in-depth perception of the traffic characteristics of upper-layer applications and the extraction of demand portraits on the eSIM terminal side, combined with the standardized description of APN capability tags on the network side, the terminal can achieve a refined matching of application requirements and APN service capabilities, which is significantly different from traditional static or blind allocation methods, ensuring that the network access point highly matches the application characteristics from the very beginning of connection establishment; the agility of connection establishment is significantly optimized: the introduced micro-timing delay evaluation mechanism enables the terminal to further evaluate and select the network path with the fastest instantaneous response among multiple matching candidate APNs, effectively avoiding potential high-delay or congested paths, greatly shortening the connection establishment delay, and improving the user experience of the initial access; the energy efficiency of the terminal is effectively improved: based on the dual context information of APN capability tags and application demand feature portraits, the terminal can intelligently query and determine the most suitable energy-saving communication parameter configuration (such as DRX cycle and PSM), enabling the energy-saving behavior of the terminal to be refined and dynamically adapted according to the current application scenario and the characteristics of the accessed APN, especially suitable for power-sensitive IoT applications, significantly extending the battery life of the terminal; the service quality maintenance ability is enhanced: this method constructs a continuously optimized closed-loop system. After the data connection is established, the eSIM terminal will continuously monitor the application service quality indicators. If the monitored QoS indicators are lower than the expected baseline and reach the preset threshold, the terminal can actively try to switch to other alternative APNs that match the portrait, effectively coping with network fluctuations or changes in application requirements, and enhancing the resilience of the connection and the stability of the user experience; in summary, the technical solution of the present invention constructs an efficient and adaptive APN dynamic selection and optimization system through the organic integration of terminal application perception, APN capability identification, path agility evaluation, and intelligent energy-saving strategies.

[0044] Example 3: This example combines Figures 1 to 3 to illustrate the implementation of an APN distribution efficiency optimization method for eSIM dynamic switching. As Figure 1As shown, the left side of the figure is scenario 1: comparison of video streaming application connection performance. The horizontal axis is marked with performance indicators, including three indicators: initial average RTT (ms), initial average throughput (Mbps) and average connection establishment delay (ms). The vertical axis is the performance indicator value. In the figure, light gray columns represent traditional static selection methods, and dark gray columns represent the method of the present invention. In the initial average RTT (ms) indicator, the traditional static method is about 65ms, while the method of the present invention is reduced to about 30ms; in the initial average throughput (Mbps) indicator, the traditional static method is about 12.5Mbps, while the method of the present invention is increased to about 28.3Mbps; in the average connection establishment delay In terms of (ms), the traditional static method is about 85ms, while the method of the present invention is shortened to about 42ms; the right side of the figure is scenario 2: IoT intermittent application energy efficiency comparison, the horizontal axis is the performance index, including the average power consumption per hour (mW), the vertical axis is the power consumption value (mW), among which the power consumption value of the traditional static method is about 185mW, while the method of the present invention is reduced to about 45mW. Through the joint matching of the energy-saving connection characteristics in the APN capability label and the intermittent small data packet characteristics of the application portrait, the terminal adjusts the communication parameters according to the policy knowledge base, such as extending the DRX cycle and enabling PSM, which significantly reduces the average power consumption per hour (mW), thereby enhancing the energy efficiency and battery life of the terminal equipment.

[0045] like Figure 2 As shown in the figure, first, the functional module in the eSIM terminal starts application type sniffing and demand abstraction, which is used to obtain and analyze the characteristic information of the currently running application to form an application demand characteristic portrait. The portrait characterizes typical application types such as video streaming, IoT and interactive types by analyzing indicators including uplink and downlink traffic ratio, average packet length and packet sending frequency. At the same time, the eSIM terminal receives information from the APN capability label on the network side. The label is obtained through a downward issuance method such as system broadcast attachment signaling or eSIM configuration. Its core features include low latency optimization, uplink bandwidth priority and energy-saving connection. The eSIM terminal matches the application demand characteristic portrait with the network side APN capability label according to the intelligent matching mechanism, and completes the candidate APN selection based on the multi-dimensional feature fitting method in the matching mechanism. After that, the eSIM terminal enters the signaling test phase, performs micro-timing delay evaluation, sends test signaling by simplifying NAS / RRC requests, collects and evaluates indicators, and performs the following operations: Minimize to determine the response agility of candidate paths, and execute the final APN connection based on the optimal selection. This step is based on the selection criteria of capability matching + response agility to ensure the optimal data link connection. Subsequently, enter the dynamic configuration process and perform energy-saving strategy adjustment. The optimization parameters include DRX cycle / PSM configuration, so that the terminal can achieve energy-saving communication effect while ensuring service quality.

[0046] likeFigure 3 As shown, the process starts from the eSIM terminal. On the one hand, the terminal obtains the capability tags and retrieves relevant information from the network-side APN capability tags. These capability tags include three core features: low-latency optimization, uplink bandwidth priority, and energy-saving connection. On the other hand, the terminal analyzes the traffic characteristics of the running applications and extracts the application demand feature portraits, which cover three typical features: video stream features, IoT intermittent features, and interactive features. Based on the above two inputs, the terminal completes the candidate APN selection through an intelligent matching mechanism and enters the micro-timing delay evaluation stage through signaling interaction testing. The system judges the response agility of the candidate paths based on the test feedback, then executes the optimal path selection, and completes the final APN connection. The selection basis for the connection is the dual criteria of capability matching and response agility. After the connection is established, the system starts the energy-saving strategy adjustment module according to the parameter dynamic configuration mechanism to further optimize parameters such as the DRX cycle / PSM configuration.

[0047] Embodiment 4: In a typical application scenario of multi-service concurrent mobile communication, the eSIM terminal is deployed in urban bus vehicles and operates as a vehicle communication control unit. The terminal runs multiple upper-layer application modules simultaneously, including: a high-frequency location reporting module for real-time trajectory positioning and dispatching management, a vehicle-mounted video backhaul module for uploading in-vehicle security monitoring data, and a background maintenance synchronization module for system status update and log synchronization. The above applications have significant differences in terms of packet structure, transmission frequency, bandwidth occupancy, and latency tolerance, thus posing higher adaptability requirements for the selection of access point names. In this scenario, the eSIM terminal first activates the application type sniffing and demand abstraction module configured inside it. This module continuously performs structural statistics on the IP layer data transmission with a fixed five-second monitoring time window. During a typical operation cycle, the monitored data features show a large number of packets sent per unit time, a small average packet size, and the total amount of uplink and downlink data being nearly equal. The system identifies this feature combination as a high-frequency and bidirectional symmetric interactive service based on this, and generates the corresponding application demand feature portrait, marked as low-latency - high-frequency - bidirectional. At the same time, in the previously completed tracking area update process, the eSIM terminal has obtained three groups of APN capability tag information from the network side, corresponding to three optional access points respectively. These capability tags are configured by the operator in a structured manner and are sent down embedded in the extended field of the NAS signaling. After receiving, the terminal parses and caches them in key-value pair format. These three groups of capability tags are respectively identified as: 1. Support low-latency optimization and uplink bandwidth priority; 2. Support energy-saving connection and stable downlink transmission; 3. Have basic Best Effort service capabilities; among them, the basic Best Effort service means that this APN does not have specific optimization features and follows the general service allocation strategy, which is applicable to non-critical service loads.

[0048] The eSIM terminal then activates its APN capability matching calculation module to perform dimensional fitting on each of the above-mentioned capability tags and the application demand feature profile identified currently, and evaluate the matching degree based on the locally preset weight scoring mechanism. In this scenario, the low-latency optimization and uplink bandwidth priority features covered by the first capability tag highly match the transmission features required for high-frequency location reporting. Therefore, it is determined by the system as the candidate access point with the highest priority at the current moment, and the other two APNs are used as alternative paths in sequence. At the same time, to verify the network response performance of this preferred candidate APN at the current moment, the terminal initiates a simplified access signaling interaction with it. Specifically, it is implemented by constructing and sending a PDU session establishment request message that only contains the minimum necessary parameters, avoiding carrying the complete user plane configuration, aiming to evaluate the immediate agility of the network side response. After the signaling is sent, the terminal activates a microsecond-level timer and records the time difference between the signaling being sent and the first clear response received from the network side. The measured micro-timing delay value is twenty-seven milliseconds, and this delay value is within the acceptable low-delay range set by the local system. Based on this, the terminal determines this APN as the current final access object and immediately establishes a formal data connection through this path.

[0049] After the data connection is established, the energy-saving policy matching module inside the eSIM terminal is triggered. It takes the APN capability label of the currently established connection and the application demand feature portrait extracted previously as context information input, and accesses the energy-saving communication policy knowledge base built into the terminal. This knowledge base forms a mapping relationship based on context combinations and predefined rules. The rule conditions include the combination of capability label features, the category of the application portrait, and the operating environment context (such as the current battery level, system load status, etc.). In the scenario of this embodiment, since the connected APN has the characteristic of low latency optimization and the current application portrait is a high-frequency interactive service, the system recommends through knowledge base matching that the power-saving mode is not enabled, and adjusts the discontinuous reception cycle parameter to the medium range. This configuration takes into account both the agility of service transmission and the energy efficiency control during the terminal communication process. The optimization result is achieved by the communication module adjusting its radio resource control parameters, specifically including extending the cell release waiting time and keeping the RRC connection in an active state to enhance the processing ability for bursty uplink data requests and service continuity. During the operation after the formal connection is established, the terminal continuously monitors the quality of service indicators of the current service data transmission through the application type sniffing module, including the average round-trip latency and the throughput per unit time, and calculates their short-term averages using a sliding window method. If any of the monitored quality indicators deviates from the performance baseline set by the current application portrait by more than the deviation threshold of 25%, the system triggers the quality of service degradation warning mechanism and automatically queries whether there are other APN capability labels with a higher matching degree to the application portrait in the local cache. If so, it restarts the path switching process to maintain the stability of the connection service quality. It should be noted that the setting of each key parameter and its adjustment logic during the implementation process are all based on engineering principles widely verified in the actual application environment. For example, the sensitive threshold range of the micro-timing delay is set to 20 to 30 milliseconds. This range is derived from the statistical analysis of terminal access data in a large number of urban bus scenarios and can more accurately distinguish the response performance differences between acceptable paths and congested paths. The setting of the medium range of the discontinuous reception cycle parameter refers to the power consumption decay curve and connection non-interruption rate evaluation results of the same device in different application modes, which all belong to the extended implementation methods known to those of ordinary skill in the art.

[0050] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An APN distribution efficiency optimization method for eSIM dynamic switching, characterized in that, The method includes the following steps: Step 1, the eSIM terminal obtains the APN capability label provided by the network side, and the APN capability label describes the service capability characteristics of each available access point name (APN). Step 2, the eSIM terminal extracts the demand feature profile of the currently running application by analyzing the traffic statistical characteristics generated by the upper-layer application within a determined monitoring time window. The traffic statistical characteristics include one or more of the average packet size, the uplink / downlink traffic ratio, and the packet sending frequency per unit time. Step 3, the eSIM terminal performs a matching calculation based on the extracted demand feature profile and the obtained APN capability label to select one or more candidate APNs that match the demand feature profile; and the eSIM terminal establishes a data connection through a final APN determined from the one or more candidate APNs.

2. The APN distribution efficiency optimization method for eSIM dynamic switching according to claim 1, characterized in that, The APN capability label is defined by the network operator and configured on the network side, and is broadcast to the eSIM terminal through the cellular network system information, or is sent to the eSIM terminal through the extended information carried when the eSIM terminal executes the attachment process, the tracking area update (TAU) process, or the routing area update (RAU) process, or is sent together when the eSIM configuration file is downloaded and updated.

3. An APN sending efficiency optimization method for eSIM dynamic switching according to claim 2, characterized in that, The step in which the eSIM terminal extracts the demand feature profile of the currently running application by analyzing the traffic statistical characteristics generated by the upper-layer application within a determined monitoring time window is specifically as follows: Under the condition of not performing deep packet detection, the application type sniffing and demand abstraction module in the eSIM terminal monitors and statistics the total uplink / downlink traffic, the total number of data packets, the average packet size of uplink data transmission, and the average packet size of downlink data transmission within the determined monitoring time window. Calculate the uplink / downlink traffic ratio and the average packet sending frequency per unit time based on the statistical results. And compare the calculated uplink / downlink traffic ratio, the average packet sending frequency per unit time, and the average packet size of uplink and downlink data transmission with the feature parameter thresholds corresponding to different application demand feature profile templates stored in the eSIM terminal to determine the demand feature profile that matches the currently running application.

4. An APN distribution efficiency optimization method for eSIM dynamic switching according to claim 1, characterized in that After an eSIM terminal selects one or more candidate APNs that match the demand feature profile and before establishing a data connection through the final APN, the following steps are further included: Step 1, if it is determined that there are at least two candidate APNs, the eSIM terminal initiates an initial access signaling interaction for each of the at least two candidate APNs respectively, and the initial access signaling interaction is intended to obtain the instantaneous response status of its corresponding network path; Step 2, the eSIM terminal captures and compares the micro-timing delay of each initial access signaling interaction from the time it is sent until the first clear response signaling from the network side is received ; and the eSIM terminal selects the candidate APN with the smallest micro-timing delay value as the final APN, where the micro-timing delay indicates the response agility of the corresponding candidate APN network path.

5. The APN distribution efficiency optimization method for eSIM dynamic switching according to claim 4, wherein The initial access signaling interaction is a PDU session establishment request NAS message that does not include complete user plane parameters, or is the initial signaling for the selection process of different core network data network names (DNN) when the RRC layer establishes a connection.

6. The APN distribution efficiency optimization method for eSIM dynamic switching according to claim 1, wherein, After the eSIM terminal establishes a data connection through the final APN, the following steps are further included: The application type sniffing and demand abstraction module in the eSIM terminal continuously monitors the application service quality (QoS) indicators of the current data connection. The QoS indicators include the throughput perceived by the eSIM terminal or the round-trip time (RTT) estimated through the application layer feedback information; if the monitored QoS indicator is lower than the QoS expected baseline associated with the current demand feature profile by a predetermined deviation threshold, and there are alternative APNs in the local cache whose APN capability labels match the demand feature profile, the eSIM terminal actively attempts to switch to one of the alternative APNs.

7. An APN distribution efficiency optimization method for eSIM dynamic switching according to claim 1, characterized in that After the eSIM terminal establishes a data connection through the final APN, the following steps are further included: The eSIM terminal profiles this dual context information based on the APN capability label of the final APN and the demand feature profile of the currently running application extracted previously; From the energy-saving policy knowledge base preset in the eSIM terminal, query and determine a set of energy-saving communication parameter configurations that match the current dual context information combination, and the energy-saving policy knowledge base defines the energy-saving communication parameter adjustment rules corresponding to different context combinations; The communication module of the eSIM terminal adjusts at least one of its current radio resource control (RRC) parameters, discontinuous reception (DRX) cycle parameters, or power saving mode (PSM) configuration parameters according to the determined energy-saving communication parameter configuration to optimize the energy consumption during data communication through the final APN.

8. An APN sending efficiency optimization method for eSIM dynamic switching according to claim 7, characterized in that The energy-saving communication parameter adjustment rules defined in the energy-saving policy knowledge base include: If the APN capability label is energy-saving connection and the application demand feature profile is small data intermittent type, configure the communication module to use a DRX cycle of 2560 ms and enable PSM; Or if the APN capability label is low latency optimization and the application demand feature profile changes to background data synchronization, configure the communication module to extend the DRX cycle.

9. The APN distribution efficiency optimization method for eSIM dynamic switching according to claim 1, wherein The APN capability label is a set of standardized descriptors used to characterize the core service characteristics of the APN, and the core service characteristics are selected from one or more of the following: low latency optimization, uplink bandwidth priority, downlink stable transmission, energy-saving connection, and basic Best Effort service.

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