Computer-implemented method for time verification in network system
By calculating the local time difference in the network system, identifying and correcting local clock overflows, the problem of unreliable identification of port local time overflows in existing technologies is solved, thus improving the reliability and accuracy of time synchronization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-05
- Publication Date
- 2026-03-27
AI Technical Summary
Existing time synchronization verification mechanisms cannot reliably identify port local time overflows in network systems, which affects the accuracy and reliability of time synchronization.
By receiving and forwarding global time in network components, calculating the difference between local times, and performing time verification based on the difference, local clock overflows are identified.
It enables reliable identification of local clock overflows, avoids misjudging permanent errors as temporary errors, and improves the reliability and accuracy of time synchronization.
Smart Images
Figure CN121750134A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a computer implementation method for time verification in a network system, a storage medium for performing the method, and a network system. In particular, this disclosure relates to time verification for safety-critical clock synchronization in a network system. Background Technology
[0002] In networked systems, global and local time are crucial for device synchronization and process coordination. However, mechanisms used to date to verify time synchronization have proven insufficient in certain scenarios and cannot reliably identify errors in forwarding time, such as in switches with boundary clocks.
[0003] Current verification methods are typically based on the assumption that a one-to-one (bijective) mapping exists between the local time and global time for all ports (master and slave ports). However, this bijective assumption has proven problematic in practice because it does not always hold true. For example, an overflow of a port's local time (clock) can lead to permanent errors because the mapping is permanently disrupted but incorrectly identified as a temporary (transient) error. Such undetected or misdiagnosed problems severely impact the accuracy and reliability of time synchronization in networked systems. Summary of the Invention
[0004] The objective of this disclosure is to provide a computer implementation method for time verification in a network system, a storage medium for performing the method, and a network system capable of reliable time verification. In particular, the objective of this disclosure is to identify local clock overflows.
[0005] This task is solved by the technical solution in the independent claim. Advantageous design solutions are given in the dependent claims.
[0006] According to one aspect of the present invention, a computer implementation method for time verification in a network system is proposed. The method includes: for a synchronization event, receiving a first global time of the network system at a first local time of the network component; for the same synchronization event, forwarding a second global time of the network system via the network component at a second local time of the network component; determining a first difference between the second local time and the first local time by the network component or a verification unit; and performing time verification for the network component based on the first difference by the verification unit.
[0007] According to the present invention, the time relationship of the local clock is determined by determining the difference between the local times at two defined time points. In other words, the offset or deviation of the time measured from the received forwarding synchronization event is determined. This relationship or time difference must meet specific conditions in the absence of errors, such as being positive within a specific interval and / or always. If this is not the case, an error can be identified. For example, when the difference is negative, an overflow of the local clock at the output port can be identified. Thus, permanent errors can be correctly identified and their misclassification as temporary (transient) errors can be avoided. Therefore, reliable time verification can be achieved.
[0008] Network components and verification units may include software components / algorithms configured to execute on at least one processor and thereby perform the functions of the respective components / units.
[0009] The term "clock (clock generator)" refers to timing in a network system to coordinate and synchronize actions.
[0010] A local clock is the internal clock of a network component, such as a switch, router, server, or processor. This clock provides a local time specific to the corresponding network component. Each network component has its own local clock, which is driven by an internal clock generator (usually in the form of a quartz oscillator).
[0011] A global clock is a centrally synchronized time source that is used as a reference by all network components in a network system. A global clock represents a common time reference or global time provided by a trusted source, such as the master clock in the network system.
[0012] The term "synchronization event" refers to a specific event in which the local clock of a network component is measured with high precision and compared with the synchronized or global time so that the local time can be adjusted according to the global time. The aim is to minimize the time difference and ensure time consistency (synchronization) throughout the network.
[0013] The preferred network component is the switch. A switch (network switch) is a device used in a network system to efficiently forward data packets between different network components. Switches act as intelligent distributors, analyzing and controlling network traffic by sending packets to the correct network components within the network.
[0014] The preferred switch is one with a boundary clock. A switch with a boundary clock is a network switch that proactively supports time synchronization in a distributed network, especially when using Precision Time Protocol (PTP) according to the IEEE 1588 standard or gPTP according to the IEEE 802.1AS standard. Unlike simple network switches that only transmit PTP messages, switches with boundary clocks take an active role in time synchronization between different devices in the network to improve achievable synchronization accuracy.
[0015] The preferred verification unit is the central component in the network system. In particular, the verification unit can centrally provide and receive time information from multiple network components to perform time verification centrally.
[0016] The preferred first difference is defined as follows:
[0017]
[0018] Here, T1 represents the first local time, at which the network component receives the first global time of the network system. T2 represents the second local time, at which the network component forwards the second global time.
[0019] The preferred verification unit is configured to identify local time overflow of network components based on a first difference. Local time overflow of a network component refers to a situation where the internal clock of a network component (such as a switch) reaches its maximum time limit and then jumps back to zero or a very low value without compensation / recording the overflow.
[0020] Overflows occur, particularly when the near-hardware representation of local time in a digital system is stored in a limited number of bits (registers) and that capacity is exhausted. To properly handle local time, register overflows in the software must be identified, counted, and accounted for. Digital systems with multiple ports (such as switches) may even have their own near-hardware local time for each port, which must be correctly converted to a local time valid for the entire system in order to distribute global time throughout the system. Without the described identification mechanism, undetected errors may occur in any implementation of the system.
[0021] Preferred network components determine the second global time by adding the difference between the second local time and the first local time to the received first global time. In other words, the global timestamp received, for example, via a slave port and forwarded, for example, via a master port, can be manipulated.
[0022] The preferred verification unit determines a positive time verification result, i.e., no error, when the first difference or its absolute value is less than a threshold. For example, for a specific network component, it can be assumed that global time forwarding typically requires a certain time interval, such as approximately 100ms. If the first difference or its absolute value is within this range, it can be considered that no error exists. A threshold can be appropriately set here. In particular, the threshold can be greater than the typical error-free forwarding time, but less than the time indicating an error.
[0023] The preferred verification unit determines a negative time verification result, i.e., an error exists, when the first difference or the absolute value of the first difference is greater than a threshold. For example, as mentioned earlier, for a specific network component, it can be assumed that the forwarding of global time typically requires a certain time interval, such as approximately 100 ms. If the first difference or its absolute value exceeds this range (e.g., 1 second or more), an error can be considered to exist, such as a local clock overflow.
[0024] The preferred threshold for the local time representation is designed to be 500ms or 1s.
[0025] Preferably, when the first difference is negative, the verification unit determines a negative time verification result, i.e., an error exists. A negative first difference means that the second local time is less than the first local time or the first local time is greater than the second local time, which is, for example, a reliable indication of local clock overflow.
[0026] The preferred method further includes determining a second difference between the second global time and the first global time by a network component or a verification unit.
[0027] The preferred second difference is defined as follows:
[0028]
[0029] Here, t1 represents the first global time received by the network component at the first local time. t2 represents the second global time forwarded by the network component at the second local time.
[0030] Preferably, further time-based verification of network components is performed based on the second difference. This is because the second difference can be used as an additional security level or to verify the first difference and the conclusions drawn from it. In this way, further monitoring is introduced to confirm the reliability of the first difference and identify potential errors early.
[0031] Preferred network components include multiple local clocks, with time verification performed individually for each. Digital systems with multiple ports (such as switches) can, in particular, have their own near-hardware local time for each port, which must be correctly converted to a local time valid for the entire system in order to distribute global time throughout the system.
[0032] This method is preferably used in safety-critical applications, such as automated driving of vehicles. In particular, accurate time synchronization is crucial in such applications, enabling error identification according to the invention to contribute to the safe and reliable execution of these safety-critical processes.
[0033] This method is preferably used for autonomous driving of vehicles, especially motor vehicles. To perform autonomous driving, multiple components, such as sensors, controllers, and switches, are interconnected in a network. The time verification according to the invention contributes to the safe and reliable operation of the network and thus to safe and reliable autonomous driving.
[0034] Within the scope of this literature, the term "autonomous driving" is understood as driving with automatic longitudinal and / or lateral guidance. Automated driving can be, for example, extended driving on a highway or limited driving within a parking area. The term "autonomous driving" includes autonomous driving with any level of automation. Exemplary levels of automation include driver assistance, partial automation, conditional automation, highly automated driving, and fully automated driving (increasing in degree of automation). These five levels of automation conform to SAE Levels 1 through 5 according to the SAE J3016 standard (SAE - Society of Automotive Engineers) as of April 30, 2021.
[0035] According to another independent aspect of this disclosure, a software (SW) program is provided. This SW program can be configured to execute on one or more processors, and thereby perform the time verification methods described herein for use in network systems.
[0036] According to another independent aspect of this disclosure, a storage medium is provided. This storage medium may include a service program (SW) configured to run on one or more processors and thereby perform the time verification methods described herein for use in a network system.
[0037] According to another independent aspect of this disclosure, software having program code is provided. This software is configured to perform a method for time verification in a network system when the software is running on one or more software-controlled devices.
[0038] According to another independent aspect of this disclosure, a network system is provided. The network system includes a processor; and a memory connected to the processor and including instructions executable by the processor to perform the time verification method for a network system described herein.
[0039] A processor or processor module is a programmable computing device, i.e. a machine or electronic circuit, that controls other components and drives algorithms (processes) based on transmitted instructions.
[0040] According to another independent aspect of the present invention, a vehicle, particularly a motor vehicle, is proposed. The vehicle includes a network system according to embodiments of this disclosure.
[0041] The term "vehicle" includes cars, trucks, vans, buses, motorhomes, motorcycles, etc., used for transporting people, goods, etc. The term "motor vehicle" specifically includes those used for transporting people. Attached Figure Description
[0042] Embodiments of this disclosure are shown in the accompanying drawings and described in more detail below. The drawings are as follows:
[0043] Figure 1 A flowchart illustrating a method for time verification in a network system according to an embodiment of the present disclosure is shown; and
[0044] Figure 2 A network system according to an embodiment of the present disclosure is illustrated schematically. Detailed Implementation
[0045] In the following text, unless otherwise stated, the same reference numerals are used for elements that are the same and have the same function.
[0046] Figure 1 A flowchart illustrating a method 100 for time verification in a network system 200 according to an embodiment of the present disclosure is shown schematically.
[0047] The method 100 includes: in block 110, for a synchronization event, receiving a first global time of the network system at a first local time of the network component in the network component; in block 120, for a synchronization event, forwarding a second global time of the network system via the network component at a second local time of the network component; in block 130, determining a first difference between the second local time and the first local time by the network component or a verification unit; and in block 140, performing time verification for the network component by the verification unit based on the first difference.
[0048] The following reference Figure 2 A detailed, exemplary implementation of method 100 is described below.
[0049] Figure 2 A network system 200 according to an embodiment of the present disclosure is illustrated schematically.
[0050] exist Figure 2 The example shows network component 210 and verification unit 220.
[0051] Network component 210 may be a switch or a network switch, but this disclosure is not limited thereto.
[0052] The verification unit 220 can be a central component in the network system 200. Specifically, the verification unit 220 can centrally provide and receive time information from multiple network components to centrally perform time verification. The time information received by the verification unit 220 in... Figure 2 The diagram is schematically shown by dashed arrows. However, this disclosure is not limited thereto and distributed checks (“local”) or centralized and distributed checks may also be conceived.
[0053] Network component 210 includes a local clock that provides or gives a local time T1, T2 specific to network component 200. Each network component in network system 200 may include its own local clock, which is driven by an internal clock generator (typically in the form of a quartz oscillator).
[0054] Network component 210 also includes at least one first port 212 configured to receive a first global time t1 of network system 200 or global clock at a first local time T1 of network component 210. The at least one first port 212 may be, for example, a slave port.
[0055] Network component 220 also includes at least one second port 214 configured to forward the second global time t2 of network system 200 or global clock to other network components, for example, the second local time T2 of network component 210. The at least one second port 214 may be, for example, a master port.
[0056] The global clock is a central synchronization time source that is used as a reference by all network components in network system 200. The global clock represents a common time reference or global time provided by a trusted source, such as the master clock in network system 200.
[0057] In some implementations, network component 210 determines the second global time t2 by adding the difference between the second local time T2 and the first local time T1 to the received first global time t1:
[0058]
[0059] Therefore, global timestamps received, for example, via slave port 212 and forwarded, for example, via master port 214 can be manipulated.
[0060] Network component 210 or verification unit 220 determines a first difference between the second local time T2 and the first local time T1:
[0061]
[0062] It should be understood here that the expression "difference between local times" can mean subtracting the first local time T1 from the second local time T2 (see above), or subtracting the second local time from the first local time (not shown).
[0063] The verification unit 220 then performs time verification for the network component 210 based on the first difference Δ1.
[0064] In some implementations, the error is an overflow of the local time or local clock of network component 210. The term "overflow" refers to a situation where the internal clock of network component 210 reaches its maximum time limit and then jumps back to zero or a very low value without compensating for / logging the overflow.
[0065] In some implementations, when the first difference Δ1 or the absolute value of the first difference Δ1 is less than a threshold, the verification unit 220 determines a positive time verification result, i.e., no error:
[0066]
[0067] For example, for a specific network component, it can be assumed that global time forwarding requires a certain time interval in extreme cases, such as approximately 100ms. If the first difference Δ1 or its absolute value is within this range, it can be considered that no error exists. A threshold can be appropriately set here. The threshold can be greater than the typical error-free forwarding time, but less than the time indicating an error.
[0068] In some implementations, when the first difference Δ1 or the absolute value of the first difference Δ1 is greater than a threshold, the verification unit 220 determines a negative time verification result, i.e., an error exists.
[0069]
[0070] For example, as mentioned earlier, for a specific network component, it can be assumed that the forwarding of global time typically requires a certain time interval, such as approximately 100 ms. If the first difference or its absolute value exceeds this range (e.g., 1 second or more), an error can be considered to exist, such as a local clock overflow.
[0071] The preferred threshold is 500ms or 1s, but this disclosure is not limited to this, mainly because the fault tolerance time is not affected by it.
[0072] Alternatively or supplementarily, when the first difference Δ1 is negative, the verification unit 200 determines a negative time verification result, i.e., an error exists:
[0073]
[0074] A negative first difference Δ1 means that the second local time T2 is less than the first local time T1 or the first local time T1 is greater than the second local time T2, which is, for example, a reliable indication of local clock overflow.
[0075] In some implementations, method 100 further includes determining a second difference Δ2 between the second global time t2 and the first global time t1 by network component 210 or verification unit 220:
[0076]
[0077] Here, t1 represents the first global time received by network component 210 at the first local time T1. t2 represents the second global time forwarded by network component 210 at the second local time T2.
[0078] In some implementations, time-based verification of network component 210 is further performed based on the second difference Δ2. The second difference Δ2 can be considered as an additional level of security or for verifying the first difference Δ1 and the conclusions drawn therefrom. This introduces further monitoring to confirm the reliability of the first difference Δ1 and identify potential errors early.
[0079] The standard for the second difference Δ2 can be set similarly to that for the first difference Δ1. In particular, a second difference Δ2 greater than the threshold can indicate an error. Similarly, a negative second difference Δ2 can indicate an error, especially an overflow.
[0080] In some implementations, network component 210 includes multiple local clocks, with time verification performed individually for each local clock. In particular, digital systems with multiple ports (such as switches) may have their own near-hardware local time for each port, which must be correctly converted to a local time valid for the entire system in order to distribute global time throughout the system.
[0081] In some implementations, method 100 is used in safety-critical applications, such as autonomous driving of vehicles. To perform autonomous driving, numerous components, such as sensors, controllers, switches, etc., are interconnected in a network. The time verification according to the invention contributes to the safe and reliable operation of the network and thus to safe and reliable autonomous driving.
[0082] According to the present invention, the time relationship of a local clock is determined by determining the difference between the local times at two defined time points. In other words, the offset or deviation of the local time is determined. This relationship or time difference must meet specific conditions in the absence of errors, such as being positive within a specific interval and / or always. If this is not the case, an error can be identified. For example, when the difference is negative, a local clock overflow can be identified. Thus, permanent errors can be correctly identified and misclassified as temporary (transient) errors can be avoided. Therefore, reliable time verification can be achieved.
[0083] Although the invention has been described and explained in more detail through preferred embodiments, it is not limited to the disclosed examples, and those skilled in the art can derive other modifications without departing from the scope of protection of the invention. Therefore, it is clear that many possible modifications exist. It is also clear that the exemplary embodiments mentioned are merely illustrative and should not be construed in any way as limiting, for example, the scope of protection, application possibilities, or design of the invention. Rather, the foregoing description and accompanying drawings enable those skilled in the art to specifically implement the exemplary embodiments, wherein various changes can be made by those skilled in the art, given an understanding of the disclosed inventive concept, such as with regard to the function or arrangement of the various elements mentioned in one exemplary embodiment, without departing from the scope of protection defined by the claims and their legal equivalents, such as further description in the specification.
Claims
1. A computer-implemented method (100) for time verification in a network system (200), comprising: - For synchronization events, the network component (210) receives the first global time (t1) of the network system (200) at the first local time (T1) of the network component (210). - For synchronization events, the network component (210) forwards (120) the second global time (t2) of the network system (200) at the second local time (T2) of the network component (210). - The network component (210) or the verification unit (220) determines (130) the first difference (Δ1) between the second local time (T2) and the first local time (T1); and - The verification unit (220) performs (140) time verification of the network component (210) based on the first difference (Δ1).
2. The method (100) according to claim 1, wherein, The network component (210) is a switch, especially a switch with a boundary clock.
3. The method (100) according to claim 1 or 2, wherein, The verification unit (220) is configured to identify the overflow of the local time of the network component (210) based on the first difference (Δ1).
4. The method (100) according to any one of claims 1 to 3, wherein, The network component (210) substantially determines the second global time (t2) by adding the difference between the second local time (T2) and the first local time (T1) to the received first global time (t1).
5. The method (100) according to any one of claims 1 to 4, wherein, The verification unit (220) - A positive time verification result is determined when the first difference (Δ1) or the absolute value of the first difference (Δ1) is less than a threshold; and - A negative time verification result is determined when the first difference (Δ1) or the absolute value of the first difference (Δ1) is greater than the threshold.
6. The method (100) according to any one of claims 1 to 5, wherein, When the first difference (Δ1) is negative, the verification unit (220) determines a negative time verification result.
7. The method (100) according to any one of claims 1 to 6, further comprising: - The second difference (Δ2) between the second global time (t2) and the first global time (t1) is determined by the network component (210) or the verification unit (220). - Further time verification is performed on the network component (210) based on the second difference (Δ2).
8. The method according to any one of claims 1 to 7, wherein, The network component includes multiple local clocks, and time verification is performed separately for each local clock.
9. A storage medium including a software program configured to run on one or more processors and thereby perform the method (100) according to any one of claims 1 to 8.
10. A network system (200), comprising: - Processor; and - A memory connected to a processor and including instructions executable by the processor to perform the method (100) according to any one of claims 1 to 8.