A clock fault locating method and network device

Abstract

The application discloses a clock fault positioning method and network equipment, and belongs to the communication technical field. In the method, the network equipment positions a clock fault source according to whether a frequency deviation between multiple input clocks and a local clock exceeds a frequency deviation threshold value or according to whether a frequency deviation between the multiple input clocks exceeds a relative frequency deviation threshold value, and the frequency deviation detection precision can be improved.

Description

[0001] This application is a divisional application. The original application has the application number 202010023012.1 and the original application date is January 9, 2020. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of communications, and more particularly to a clock fault location method and network device. Background Technology

[0003] In the field of mobile communications, the clocks of wireless base stations require frequency synchronization to ensure normal service operation. Wireless services require frequency synchronization accuracy of ±0.05 parts per million (ppm). Figure 1 As shown, in the mobile bearer network, the clock server transmits the clock to the base station for frequency synchronization via mobile bearer device 1, mobile bearer device 2, and mobile bearer device 3. Currently, physical layer synchronization technology or Precision Timing Protocol (PTP) synchronization technology can be used to provide frequency synchronization solutions for the base station.

[0004] In the above scheme, it is difficult to determine which clock malfunctions when a clock fails. Summary of the Invention

[0005] This application proposes a clock fault location method for locating the faulty clock based on the frequency offset of multiple received clocks.

[0006] In a first aspect, a method for clock fault location is provided, comprising: a network device acquiring frequency offsets between at least two clocks and a local clock. When a first condition is met, the network device determines a local clock fault, the first condition including a first quantity greater than a second quantity, the first quantity being the number of clocks among the at least two clocks whose frequency offsets from the local clock exceed a frequency offset threshold, and the second quantity being the number of clocks among the at least two clocks whose frequency offsets from the local clock do not exceed the frequency offset threshold; and / or

[0007] When the second condition is met, the network device determines that the first clock of the at least two clocks is faulty. The second condition includes that the frequency offset between the first clock and the local clock exceeds the frequency offset threshold, and that the frequency offset between all other clocks of the at least two clocks except the first clock and the local clock does not exceed the frequency offset threshold.

[0008] The clock fault localization method provided in the first aspect involves a network device determining a local clock fault by determining that the number of clocks whose frequency offset from the local clock exceeds a frequency offset threshold among at least two received clocks is greater than the number of clocks whose frequency offset does not exceed the threshold. Alternatively, the network device determines that the clock exceeding the frequency offset threshold is faulty by determining that the frequency offset of one of the at least two received clocks exceeds the frequency offset threshold, while the frequency offsets of the other clocks do not exceed the threshold. The local clock can be the clock of the network device's local crystal oscillator. The at least two received clocks can be all clocks received by the network device, or a portion of all clocks received. For example, assuming the network device receives a total of 50 clocks, the at least two received clocks could be 40 of them, or all 50 clocks. In this way, the network device can pinpoint the source of the fault, i.e., whether it is a local clock fault or a faulty received clock.

[0009] In one possible implementation of the first aspect, the first quantity being greater than the second quantity in the first condition can be: the second quantity is zero and the first quantity is the number of the at least two clocks. Alternatively, it can be understood that if the frequency offset between all clocks received by the network device and the local clock exceeds a frequency offset threshold, the network device determines that there is a local clock failure.

[0010] In one possible implementation of the first aspect, the at least two clocks include three or more clocks. Network devices typically have multiple ports, each capable of receiving clocks from other devices.

[0011] In one possible implementation of the first aspect, the frequency offset threshold is ±4.6 ppm. According to ITU-T G.8262, the frequency offset of mobile bearer equipment relative to a standard clock (such as a GPS clock) should not exceed ±4.6 ppm. The frequency offset threshold in the first aspect can be referred to as the network equipment frequency offset threshold or the mobile bearer equipment frequency offset detection threshold.

[0012] In one possible implementation of the first aspect, the network device is a device that supports physical layer clock synchronization or precise clock protocol synchronization. Thus, the method provided in the first aspect can be widely applied to networks requiring physical layer clock synchronization or precise clock protocol synchronization, such as mobile bearer networks or power grids.

[0013] In one possible implementation of the first aspect, the network device generates an alarm indicating a clock fault source. After the network device locates the clock fault source, it can generate an alarm to promptly notify the network management system of the cause of the clock fault.

[0014] The second aspect provides a clock fault location method, comprising: when a condition is met, a network device determines a first clock fault, the condition including that the frequency offset between the first clock and all other clocks among a plurality of clocks exceeds a relative frequency offset threshold, wherein the first clock is one of the plurality of clocks.

[0015] The second aspect provides a method in which the network device determines a clock fault by identifying a clock whose frequency offset exceeds a relative frequency offset threshold among at least three received clocks. It should be understood that the at least three received clocks can be all clocks received by the network device, or a portion of all clocks received. For example, assuming the network device receives a total of 50 clocks, the at least three received clocks could be 40 of them, or all 50 clocks.

[0016] In this way, even if the frequency offsets between the multiple clocks received by the network device and the local clock do not exceed the network device's frequency offset threshold, the network device can still pinpoint the source of the fault as one of the received clocks. It should be understood that "multiple clocks" here refers to three or more clocks.

[0017] In one possible implementation of the second aspect, the condition further includes: the frequency offsets between the other clocks do not exceed the relative frequency offset threshold. Here, "frequency offsets between other clocks" refers to the frequency offsets between any two of the other clocks. This allows for a more accurate determination that only the first clock is faulty.

[0018] In one possible implementation of the second aspect, the relative frequency offset threshold is ±4.44 parts per billion (ppb). This relative frequency offset threshold can also be called the reference clock source frequency offset detection threshold, or the clock source frequency offset detection threshold. Since 1 ppm = 1000 ppb, this scheme can locate the fault source while significantly improving the frequency offset detection accuracy of the reference clock source.

[0019] In one possible implementation of the second aspect, the network device is a device that supports physical layer clock synchronization or precise clock protocol synchronization. Thus, the method provided in the second aspect can be widely applied to networks requiring physical layer clock synchronization or precise clock protocol synchronization, such as mobile bearer networks and power grids.

[0020] In one possible implementation of the second aspect, the network device generates an alarm indicating a first clock failure. After the network device identifies a clock failure, it can generate an alarm to promptly notify the network management system of the clock failure.

[0021] Thirdly, a network device for locating clock faults is provided. The network device includes an acquisition unit, a first determination unit, and / or a second determination unit. The acquisition unit is used to acquire the frequency offset between at least two clocks and a local clock. The first determination unit is used to determine a local clock fault when a first condition is met, wherein the first condition includes a first quantity greater than a second quantity, where the first quantity is the number of clocks among the at least two clocks whose frequency offset between them and the local clock exceeds a frequency offset threshold, and the second quantity is the number of clocks among the at least two clocks whose frequency offset between them and the local clock does not exceed the frequency offset threshold. The second determination unit is used to determine whether a second condition is met, wherein the second condition includes that the frequency offset between the first clock among the at least two clocks and the local clock exceeds the frequency offset threshold, and the frequency offset between all other clocks among the at least two clocks (excluding the first clock) and the local clock does not exceed the frequency offset threshold.

[0022] In one possible implementation of the third aspect, the first quantity is greater than the second quantity when the second quantity is zero and the first quantity is the number of the at least two clocks.

[0023] In one possible implementation of the third aspect, the at least two clocks include three or more clocks.

[0024] In one possible implementation of the third aspect, the frequency offset threshold is ±4.6 ppm.

[0025] In one possible implementation of the third aspect, the network device is a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization.

[0026] In one possible implementation of the third aspect, the network device further includes an alarm unit for generating an alarm that indicates a clock fault source.

[0027] For the third aspect and the beneficial effects of any possible implementation of the third aspect, please refer to the description of the corresponding first aspect and the beneficial effects of any possible implementation of the first aspect.

[0028] Fourthly, a network device for locating clock faults is provided. The network device includes a judgment unit for determining whether a condition is met. The condition includes that the frequency offset between a first clock and all other clocks among a plurality of clocks exceeds a relative frequency offset threshold, wherein the first clock is one of the plurality of clocks. The network device further includes a determination unit for determining that the first clock is faulty when the judgment unit determines that the condition is met.

[0029] In one possible implementation of the fourth aspect, the condition further includes: the frequency offsets between the other clocks do not exceed the relative frequency offset threshold.

[0030] In one possible implementation of the fourth aspect, the relative frequency offset threshold is ±4.44 ppb.

[0031] In one possible implementation of the fourth aspect, the network device is a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization.

[0032] In one possible implementation of the fourth aspect, the network device generates an alarm indicating the first clock failure.

[0033] For the fourth aspect and the beneficial effects of any possible implementation of the fourth aspect, please refer to the description of the corresponding second aspect and the beneficial effects of any possible implementation of the second aspect.

[0034] Fifthly, a network device for locating clock faults is provided. The network device includes an interface, a clock circuit, and a processor. The interface is used to receive at least two clocks. The clock circuit is used to acquire the frequency offset between the at least two clocks and a local clock. The processor is used to:

[0035] When a first condition is met, the network device determines that the local clock is faulty. The first condition includes a first quantity greater than a second quantity. The first quantity is the number of clocks among the at least two clocks whose frequency offset from the local clock exceeds a frequency offset threshold, and the second quantity is the number of clocks among the at least two clocks whose frequency offset from the local clock does not exceed the frequency offset threshold.

[0036] and / or

[0037] When the second condition is met, the network device determines that the first clock of the at least two clocks is faulty. The second condition includes that the frequency offset between the first clock and the local clock exceeds the frequency offset threshold, and that the frequency offset between all other clocks of the at least two clocks except the first clock and the local clock does not exceed the frequency offset threshold.

[0038] In one possible implementation of the fifth aspect, the first quantity is greater than the second quantity when the second quantity is zero and the first quantity is the number of the at least two clocks.

[0039] In one possible implementation of the fifth aspect, the at least two clocks include three or more clocks.

[0040] In one possible implementation of the fifth aspect, the frequency offset threshold is ±4.6 ppm.

[0041] In one possible implementation of the fifth aspect, the network device is a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization.

[0042] In one possible implementation of the fifth aspect, the processor is also configured to generate an alarm indicating a clock fault source.

[0043] For the benefits of the fifth aspect and any possible implementation of the fifth aspect, please refer to the description of the benefits of the corresponding first aspect and any possible implementation of the first aspect.

[0044] A sixth aspect provides a network device for locating clock faults, including an interface and a processor. The interface is configured to receive multiple clocks, and the processor is configured to: determine a first clock fault when a condition is met, the condition including that the frequency offset between the first clock and all other clocks among the multiple clocks exceeds a relative frequency offset threshold, wherein the first clock is one of the multiple clocks.

[0045] In one possible implementation of the sixth aspect, the condition further includes: the frequency offsets between the other clocks do not exceed the relative frequency offset threshold.

[0046] In one possible implementation of the sixth aspect, the relative frequency offset threshold is ±4.44 ppb.

[0047] In one possible implementation of the sixth aspect, the network device is a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization.

[0048] In one possible implementation of the sixth aspect, the processor is also configured to generate an alarm indicating the first clock failure.

[0049] For the sixth aspect and the beneficial effects of any possible implementation of the sixth aspect, please refer to the description of the corresponding second aspect and the beneficial effects of any possible implementation of the second aspect.

[0050] A seventh aspect provides a computer-readable medium including instructions that, when executed on a computer, cause the computer to perform one or more of the following steps:

[0051] When a first condition is met, the local clock of the network device is determined to be faulty. The first condition includes a first quantity greater than a second quantity. The first quantity is the number of clocks among at least two clocks whose frequency offset from the local clock exceeds a frequency offset threshold. The second quantity is the number of clocks among at least two clocks whose frequency offset from the local clock does not exceed the frequency offset threshold.

[0052] When the second condition is met, it is determined that the first clock of the at least two clocks is faulty. The second condition includes that the frequency deviation between the first clock and the local clock exceeds the frequency deviation threshold, and the frequency deviation between all other clocks of the at least two clocks except the first clock and the local clock does not exceed the frequency deviation threshold.

[0053] When a third condition is met, a second clock fault is determined. The third condition includes that the frequency offset between the second clock and all other clocks among the plurality of clocks exceeds a relative frequency offset threshold. The second clock is one of the plurality of clocks.

[0054] In one possible implementation of the seventh aspect, the frequency offset threshold is ±4.6 ppm and the relative frequency offset threshold is ±4.44 ppb.

[0055] In one possible implementation of the seventh aspect, the first quantity in the first condition is greater than the second quantity, specifically: the second quantity is zero and the first quantity is the number of the at least two clocks.

[0056] In one possible implementation of the seventh aspect, the third condition further includes: the frequency offsets between the other clocks do not exceed the relative frequency offset threshold.

[0057] In one possible implementation of the seventh aspect, the network device is a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization.

[0058] In one possible implementation of the seventh aspect, the instructions further cause the computer to generate an alarm after determining the source of the clock failure, the alarm indicating the clock source.

[0059] The solution provided in this application allows network devices (such as those supporting physical layer clock synchronization or precise clock protocol synchronization) to determine whether the fault lies with the network device's local clock or a specific received clock by judging whether the frequency offset between at least two received clocks and the local clock exceeds a frequency offset threshold. The network device can also determine whether a specific clock is faulty by comparing the frequency offsets between three or more received clocks, with an accuracy far exceeding ±4.6 ppm. Furthermore, after locating the source of the clock fault, an alarm can be generated to indicate the fault source. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of clock transmission in a mobile bearer network;

[0061] Figure 2 This is a schematic diagram illustrating the clock frequency offset accuracy specified in the standards organization;

[0062] Figure 3This is a schematic diagram illustrating an application scenario of an embodiment of the present invention;

[0063] Figure 4 This is a schematic diagram illustrating an application scenario of an embodiment of the present invention;

[0064] Figure 5 This is a schematic diagram illustrating an application scenario of an embodiment of the present invention;

[0065] Figure 6 This is a flowchart illustrating an embodiment of the present invention;

[0066] Figure 7 This is a flowchart illustrating an embodiment of the present invention;

[0067] Figure 8 This is a schematic diagram illustrating the application scenario of the present invention;

[0068] Figure 9 This is a schematic diagram illustrating the clock frequency offset output requirements;

[0069] Figure 10 This is a schematic diagram of the network device structure;

[0070] Figure 11 Network device structure diagram;

[0071] Figure 12 Network device structure diagram. Detailed Implementation

[0072] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, other technical solutions and drawings that can achieve the same invention can be obtained based on these drawings without any creative effort.

[0073] Device A sends a clock signal to Device B, and Device A is referred to as the reference clock source for Device B. According to the standard ITU-T G.811, the frequency deviation of the clock of the clock server device relative to a standard clock (such as a GPS clock) should not exceed 0.01 ppb (i.e., ±10) over a long period. -5According to the standard ITU-T G.8262, the frequency offset of the local clock of mobile bearer equipment relative to a standard clock (such as a GPS clock) should not exceed ±4.6 ppm. Therefore, for mobile bearer equipment, the frequency offset detection threshold accuracy should generally not exceed ±4.6 ppm. Here, "±" refers to a range; for example, taking ±4.6 ppm as an example, values ​​greater than +4.6 ppm or less than -4.6 ppm are considered to exceed the threshold. The mobile bearer equipment refers to equipment in a mobile bearer network, which typically includes a mobile backhaul network and a mobile fronthaul network.

[0074] like Figure 2 As shown: Clock servers 1-3 respectively send clock signals to the mobile bearer device, and each of clock servers 1-3 serves as a reference clock source for the mobile bearer device. The long-term frequency deviation of clock server 1 relative to the standard clock is 10. -5 ppm (also known as the frequency offset of reference clock source 1 for mobile carrier equipment is 10) -5 (ppm), the long-term frequency deviation of the clocks of clock servers 2 and 3 relative to the standard clock is -10. -5 The frequency deviation of these three clock servers relative to the standard clock is within the threshold, meeting the requirements of ITU-T G.811; the frequency deviation of the mobile bearer equipment clock relative to the standard clock is 4.6 ppm, meeting the requirements of ITU-T G.8262.

[0075] When a mobile bearer device detects that the clock (or input clock) received at one of its ports exceeds a certain threshold (e.g., ±4.6 ppm) relative to its local clock, the mobile bearer device cannot determine whether the input clock at that port is faulty or the local clock of the mobile bearer device is faulty. Here, the local clock can be the clock of the mobile bearer device's local crystal oscillator. In this application, the transmitting clock includes the transmitting clock signal, and the receiving clock includes the receiving clock signal.

[0076] This invention provides a technical solution for clock fault location. In typical scenarios, mobile bearer devices have at least two reference clock sources. In one implementation of this invention, the clock of the specific device that has failed can be determined based on the majority decision principle. It should be noted that this solution is not limited to mobile bearer devices; it can be applied to devices that support physical layer clock synchronization or precise clock protocol synchronization (such as routers, switches, or packet switching equipment), with mobile bearer devices being one type of such device. For example, this solution can be used not only for devices supporting physical layer clock synchronization or precise clock protocol synchronization in mobile bearer networks, but also for devices supporting physical layer clock synchronization or precise clock protocol synchronization in power grids. The design concept of this solution is as follows:

[0077] 1) For network devices supporting physical layer clock synchronization or precise clock protocols, if the frequency offset detection values ​​between two or more received clocks and the local clock all exceed a judgment threshold (this threshold can be called the frequency offset threshold, network device frequency offset threshold, or mobile bearer device frequency offset detection threshold, with a range of ±4.6ppm), then the local device clock is considered to be faulty. This is because, in general scenarios, the probability of two or more reference clock sources failing simultaneously is relatively low. Figure 4 As shown, if the frequency offset detection value offset1 of the clock of reference clock source 1 relative to the local clock is 4.7ppm, and the frequency offset detection value offset2 of the clock of reference clock source 2 relative to the local clock is 4.7ppm, both offset1 and offset2 exceed the frequency offset threshold, then the mobile carrier equipment determines that the local clock has failed.

[0078] 2) If, among two or more received clocks, the frequency offset between reference clock source 1 and the local clock exceeds the frequency offset threshold, while the frequency offsets between all other reference clock sources and the local clock do not exceed the frequency offset threshold, the network device considers reference clock source 1 to be faulty. This is because the probability of the local clock and other reference clock sources simultaneously failing is relatively small. Figure 5 As shown, the mobile bearer device receives clocks from two clock servers. The frequency offset between the clock of reference clock source 1 and the standard clock is degraded to -0.1ppm, and the frequency offset between the local clock of the mobile bearer device and the standard clock is 4.6ppm. Therefore, the frequency offset detection value offset1 of the clock of reference clock source 1 relative to the local clock is 4.7ppm (exceeding the frequency offset threshold), and the frequency offset detection value offset2 of the clock of reference clock source 2 relative to the local clock is 4.6ppm (not exceeding the frequency offset threshold). The network device determines that the clock received from reference clock source 1 is faulty.

[0079] It should be understood that the frequency offset of reference clock source 1 relative to the local clock has the same meaning as the frequency offset between reference clock source 1 and the local clock. Figure 4 For example, offset1 can be 4.7-0=4.7ppm, or offset1 can be 0-4.7=-4.7ppm. Whether it is 4.7ppm or -4.7ppm, it exceeds ±4.6ppm.

[0080] Although Figure 4 and Figure 5 Only two reference clock sources are shown, but the number of reference clock sources is not limited to two; it can be three or more. When there are three or more reference clock sources, if the frequency offset between the clocks of all reference clock sources and the local clock exceeds the frequency offset threshold, or if the frequency offset between the clocks of most reference clock sources (e.g., more than 50% of the reference clock sources) and the local clock exceeds the frequency offset threshold, the mobile bearer determines that the local clock is faulty.

[0081] The following is based on Figure 6 Let me describe the above scheme in detail. Figure 6 Performed by a network device, which may be a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization, and the network device is connected to at least two reference clock sources.

[0082] S601, the network device receives at least two clocks.

[0083] The network device receives clock signals from at least two reference clock sources. For example... Figure 4 or Figure 5 As shown.

[0084] S602, The network device obtains the frequency offset between at least two of the received clocks and the local clock.

[0085] For example, if a network device is connected to 50 reference clock sources and receives 50 clock signals, the network device can decide, based on its own processing capabilities, whether to consider all 50 clock signals or a portion of them, such as 40 clock signals, when locating the source of a clock fault.

[0086] For example, if the network device has strong processing capabilities, consider all 50 clock cycles. Then the network device calculates the frequency offset of these 50 clock cycles and the local clock separately, that is, calculates offset1, offset2, ... offset50.

[0087] S603. The network device determines whether a first condition is met. The first condition includes a first quantity greater than a second quantity. The first quantity is the number of clocks among the at least two clocks under consideration whose frequency offset from the local clock exceeds a frequency offset threshold. The second quantity is the number of clocks among the at least two clocks under consideration whose frequency offset from the local clock does not exceed the frequency offset threshold. If the first condition is met, proceed to S604.

[0088] S604. The network device has determined that the local clock is faulty.

[0089] In S603 and S604, the network device can compare the calculated 50 offsets with the frequency offset threshold to determine whether the frequency offset threshold is exceeded. For example, when the network device detects clock frequency offset over a period of 900 seconds, the frequency offset threshold can be set to ±4.6ppm. For instance, if 48 of the 50 clocks exceed the frequency offset threshold and 2 do not, the network device determines that there is a local clock fault. Conversely, if 50 of the 50 clocks exceed the frequency offset threshold and the number of clocks that do not exceed it is zero—in other words, the frequency offset between all 50 clocks and the local clock exceeds the frequency offset threshold—then the network device determines that there is a local clock fault.

[0090] S605. The network device generates an alarm indicating a local clock failure.

[0091] For example, the network device sends an alarm to the network management system, indicating a local clock failure. Alternatively, the network device can log the local clock failure.

[0092] S606. The network device determines whether a second condition is met. The second condition includes that the frequency offset between the first clock and the local clock exceeds the frequency offset threshold, and that the frequency offset between all clocks other than the first clock and the local clock does not exceed the frequency offset threshold. If the second condition is met, proceed to S607.

[0093] S607, The network device has identified a first clock failure.

[0094] In S606 and S607, the network device can compare the calculated 50 offsets with the frequency offset threshold to determine whether the frequency offset threshold is exceeded. For ease of description, we number the 50 clocks under consideration as 1, 2, 3, ... 50. If the offset 3 of clock number 3 exceeds the frequency offset threshold, but the offsets of the other 49 clocks do not exceed the frequency offset threshold, then the network device determines that clock number 3 (i.e., the first clock) is faulty.

[0095] S608. The network device generates an alarm, which indicates a first clock failure.

[0096] For example, the network device sends an alarm to the network management system indicating a fault in clock 3. Alternatively, the network device can log the fault in clock 3.

[0097] It should be noted that the network device's determination of whether the first and second conditions are met can be an "OR" relationship, meaning the network device only checks if the first condition is met without considering whether the second condition is met; or it only checks if the second condition is met without considering whether the first condition is met. Alternatively, the determination of whether the first and second conditions are met can be an "AND" relationship. For example, at the first time point, the network device considers 50 clock cycles, which meet the first condition; at the second time point, these 50 clock signals change, meeting the second condition. If the network device determines that the first condition is met at the first time point and that the second condition is met at the second time point, then the determination of whether the first and second conditions are met is said to be an "AND" relationship.

[0098] The local clock mentioned above can be the clock of a local crystal oscillator.

[0099] Figure 6 In the scheme described in the embodiment, the network device can locate the source of the clock fault, that is, determine whether it is a local clock fault or a received clock fault, and can further generate an alarm to indicate the source of the clock fault, which helps to quickly eliminate the clock fault.

[0100] The present invention also provides another embodiment to solve the problem of low accuracy of network equipment frequency offset threshold (e.g., ±4.6ppm), which leads to base station service failure. Figure 3As shown, the mobile bearer device receives clocks from clock servers 1-3. When the clock of clock server 1 has a small degradation (e.g., a frequency deviation of 0.1ppm relative to the standard clock), the mobile bearer device's local clock detects that the frequency deviation of reference clock source 1's clock relative to the local clock is 4.4ppm (which can be recorded as offset1 = 4.5 - 0.1 = 4.4ppm), and the frequency deviations of reference clock source 2 and reference clock source 3 relative to the local clock are both 4.5ppm (which can be recorded as offset 2 = 4.5 - 0 = 4.5ppm, offset 3 = 4.5 - 0 = 4.5ppm). At this time, the mobile bearer device determines that the clocks of reference clock sources 1-3 do not exceed the mobile bearer device's frequency deviation threshold (e.g., ±4.6ppm). Assuming that clock servers 1, 2, and 3 are all of primary reference clock (PRC) quality level, but PRC 1 has a higher priority than PRC 2 and 3, and the mobile bearer equipment chooses to track PRC 1, then the clock frequency offset sent by the mobile bearer equipment to the base station equipment relative to the standard clock will be approximately 0.1 ppm. However, since the base station requires a clock frequency offset of no more than ±0.05 ppm, this scenario will lead to base station failure.

[0101] against Figure 3 In such scenarios, after receiving multiple clocks, network devices can calculate the frequency offsets (also known as relative offsets or relative reference offsets) between the received clocks. If the frequency offset of one of the clocks relative to the other received clocks exceeds the relative offset threshold, then the clock can be determined to be faulty.

[0102] The following is based on Figure 7 This section describes in detail the process described above for determining the source of a clock fault by judging whether the relative frequency offset exceeds the relative frequency offset threshold. Figure 7 Performed by a network device, which may be a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization, and the network device is connected to at least three reference clock sources.

[0103] S701, the network device receives at least 3 clocks.

[0104] For example, such as Figure 3 As shown, the network device receives the clock sent by the clock server 1-3 (i.e., reference clock source 1-3).

[0105] S702, The network device obtains the frequency offset between at least three clocks in the received clock.

[0106] like Figure 6In the illustrated embodiment, the network device can determine, based on its processing capabilities, whether to consider all received clock signals or a portion of them when locating the source of a clock fault. The following example illustrates this using the scenario of receiving three clock signals and considering all three.

[0107] The network device can calculate the frequency offset between these three clocks (i.e., calculate the three relative frequency offsets).

[0108] For example, the network can calculate the frequency offset between these three clocks in two ways.

[0109] Method 1: Network devices according to Figure 6 S602 in the middle, targeting Figure 3 In the given scenario, offset1 = 4.4 ppm, offset2 = 4.5 ppm, and offset3 = 4.5 ppm were measured respectively. Then, the frequency offset (relative frequency offset) between these three clocks was calculated:

[0110] Relativeoffset12=Offset1–Offset2=-0.1ppm

[0111] Relativeoffset13=Offset1–Offset3=-0.1ppm

[0112] Relativeoffset23=Offset2–Offset3=0ppm

[0113] It should be understood that calculating the frequency offset between clocks can also be done as follows:

[0114] Relativeoffset12=Offset2–Offset1=0.1ppm

[0115] Relativeoffset13=Offset3–Offset3=0.1ppm

[0116] Relativeoffset23=Offset3–Offset2=0ppm

[0117] Method 2: Directly measure the frequency offset between these three clocks using network devices:

[0118] Relativeoffset12=0.1-0=0.1ppm

[0119] Relativeoffset13=0.1-0=0.1ppm

[0120] Relativeoffset 23=0-0=0.1ppm

[0121] It should be understood that measuring the frequency offset between clocks can also be:

[0122] Relativeoffset12=0-0.1=-0.1ppm

[0123] Relativeoffset13=0-0.1=-0.1ppm

[0124] Relativeoffset 23=0-0=0.1ppm

[0125] S703. Determine whether the conditions are met. If the conditions are met, execute S704. The conditions include that the frequency offset between the first clock and all other clocks among the plurality of clocks exceeds the relative frequency offset threshold, where the first clock is one of the plurality of clocks.

[0126] S704, First clock fault identified.

[0127] In S703 and S704, it is possible to compare whether Relativeoffset12, Relativeoffset13, and Relativeoffset23 exceed the relative frequency offset threshold. The relative frequency offset threshold can also be called the reference clock source frequency offset detection threshold or the clock source frequency offset detection threshold. For example, the setting of the relative frequency offset threshold can consider the following two scenarios:

[0128] Scenario 1: If the network device and the clock server have a one-hop connection, such as... Figure 2-5 In this case, the relative frequency offset threshold can be set to ±2*0.03ppb (corresponding to a detection period of 900 seconds), or ±2*10 -5 ppm (corresponding to a long-term detection period). This is because if the reference clock source is a PRC, according to the standard ITU-T G.811, the clock frequency offset accuracy of the PRC should not exceed 0.03 ppb (corresponding to a detection period of 900 seconds) or ±10. -5 The relative frequency offset threshold can be set to ±0.06 ppb (corresponding to a long-term detection period) or ±2*10 ppm (corresponding to a detection period of 900 seconds). -5 ppm (corresponding to long-term detection period).

[0129] Scenario 2: If the network device and the clock server are connected via a mobile bearer network, meaning there are other mobile bearer devices between the clock server and the mobile bearer device, the relative frequency offset threshold can be set to ±4.44 ppb. For example... Figure 8As shown, there are mobile bearer devices 1 and 4 between clock server 1 and mobile bearer device 7, mobile bearer devices 2 and 5 between clock server 2 and mobile bearer device 7, and mobile bearer devices 3 and 6 between clock server 3 and mobile bearer device 7. For mobile bearer device 7, there are three reference clock sources (mobile bearer devices 4, 5, and 6). According to standard ITU-T G.8261, the clock performance output of any mobile bearer device (e.g., mobile bearer devices 1 and 4 both track clock server 1) that tracks a device with a clock class of PRC (such as clock server 1) should meet the following Maximum Time Interval Error (MTIE) requirement (see [reference]). Figure 9 Converted to frequency offset, this means: the frequency offset of the mobile carrier device's output relative to a standard clock (such as a GPS clock) should not exceed ±0.02ppm (corresponding to a detection period of 100 seconds), or ±0.002ppm (corresponding to a detection period of 100 seconds), or ±2.22ppb (corresponding to a detection period of 900 seconds). Therefore, the relative frequency offset threshold can be set to 2 * ±2.22ppb = ±4.44ppb (corresponding to a detection period of 900 seconds). Alternatively, the relative frequency offset threshold can be ±4.44ppb.

[0130] It can be seen that whether it is ±0.06ppb or ±2*10 -5 Both ppm and ±4.44 ppb have much higher accuracy than the frequency offset threshold for mobile bearer equipment (such as ±4.6 ppm). Since the requirement for base station services is 0.05 ppm, the accuracy of the two relative frequency offset thresholds mentioned above can meet the requirements of base station services.

[0131] For example, in Figure 3 In the example shown, the relative frequency offset threshold can be set to ±0.06 ppb. The frequency offset of the clock from reference clock source 1 relative to the clock from reference clock source 2, and also relative to the clock from reference clock source 3, both exceed the relative frequency offset threshold. Therefore, Figure 3 The mobile carrier device in the system determines that the clock of reference clock source 1 (i.e., the first clock) is faulty.

[0132] exist Figure 8 In the example shown, the relative frequency offset threshold can be set to ±4.44ppb. According to the above method, the mobile carrier device 7 can still determine the clock failure of the reference clock source 1.

[0133] In one possible implementation, the condition in S703 also includes that the frequency offsets between other clocks do not exceed the relative frequency offset threshold; that is, the condition is satisfied only when the frequency offsets between any two of the other clocks do not exceed the relative frequency offset threshold. Regarding... Figure 3In this scenario, other clocks refer to the clocks of reference clock sources 2 and 3, with a relative offset of 23 = 0 ppm, which does not exceed the relative frequency offset threshold. This allows for a more accurate determination that the clock failure is only at reference clock source 1.

[0134] S705. The network device generates an alarm indicating a first clock failure.

[0135] For details, please refer to the description in S608, which will not be repeated here.

[0136] It can be seen that, Figure 8 In the embodiment, even if the frequency offset of all input clocks relative to the local clock does not exceed the mobile bearer equipment frequency offset threshold (e.g., ±4.6ppm), if the frequency offset of one input clock relative to other input clocks exceeds the relative frequency offset threshold (e.g., ±0.06ppb, or ±4.44ppb), the network device can still locate the fault source and issue an alarm in a timely manner to help quickly troubleshoot base station faults. Figure 8 The solution in this embodiment improves the frequency offset detection accuracy of the input clock by the network device.

[0137] Network devices can be configured to choose to perform only one operation. Figure 6 The solution in the embodiment, or only the execution of Figure 8 The solution in the embodiment, or Figure 6 and Figure 8 The solutions in the embodiments are all executed.

[0138] The embodiments of this invention can also be applied to other fields requiring clock synchronization, such as power and media. These fields also have clock synchronization needs, and the clock synchronization schemes can be consistent with those of the embodiments of this invention.

[0139] The mobile bearer device in the above embodiments can be a router or switch, or an optical transport network (OTN) device or a synchronous digital hierarchy (SDH) device, or a microwave device, or a passive optical network (PON) device or a digital subscriber line (DSL) device.

[0140] Figure 10 This is a structural diagram of network device 1000. Network device 1000 can be... Figure 1-5 as well as Figure 8 Mobile carrier equipment in the middle, or it can be Figure 6 and Figure 7 The network device 1000 includes an acquisition unit 1001, and further includes a first determination unit 1002 and / or a second determination unit 1003. The acquisition unit 1001 can be used to perform... Figure 6 S601 and S602 in the above. The first determining unit 1002 can be used to execute Figure 6 S603 and S604 in the example. The second determining unit 1003 can be used to execute... Figure 6 The network device 1000 may also include an alarm unit 1004 for performing S606 and S607. Figure 6 S605 or S608 in the S605 series. Please refer to the detailed description below. Figure 6 The descriptions of the corresponding steps in the embodiments are not repeated here.

[0141] Figure 11 This is a structural diagram of network device 1100. Network device 1100 can be... Figure 1-5 as well as Figure 8 Mobile carrier equipment in the middle, or it can be Figure 6 and Figure 7 The network device 1100 may include a judgment unit 1101 and a determination unit 1102. The judgment unit 1101 is used to perform... Figure 7 S702 and S703 in the middle; the determining unit 1102 is used to execute Figure 7 The S704 in the example. Network device 1100 may also include an alarm unit 1103 for performing... Figure 7 S705 in [the context of the text]. For a detailed description, please refer to [the relevant documentation / reference]. Figure 6 The descriptions of the corresponding steps in the embodiments are not repeated here.

[0142] Figure 12 A schematic diagram of the structure of network device 1200. This network device 1200 can be... Figure 1-5 as well as Figure 8 Mobile carrier equipment in the middle, or it can be Figure 6 and Figure 7 The network device 1200 includes at least two interfaces, a clock circuit, and a processor. The multiple interfaces of the network device can be distributed across multiple interface cards, and each interface card can have multiple interfaces. There can be one or more processors. The clock circuit may include a local crystal oscillator. Alternatively, the local crystal oscillator can be independent of the clock circuit.

[0143] In this configuration, network device 1200 is connected to multiple reference clock sources and receives clock signals from these sources. Thus, the interface of network device 1200 executes... Figure 6 or Figure 7 The operation of receiving clocks. Referring to the descriptions in S602 or S702, network device 1200 can consider processing all received clocks or only a portion of them. Clocks received from each interface are sent to the clock circuit. The clock circuit and processor can have the following optional operations:

[0144] 1. The clock circuit can perform... Figure 6In step S602, the frequency offset between at least two of the received clock signals and the local crystal oscillator is obtained, and these frequency offsets are then sent to the processor. The processor can execute steps S603 and S604, and / or S606 and S607. Further, the processor can execute step S605 or S608, and the generated alarm can be sent to the network management device through a certain interface.

[0145] 2. The clock circuit can perform... Figure 7 In step S702, the frequency offset between at least three clocks in the received clock is obtained (see the description of method two in S702), and then these frequency offsets are sent to the processor for execution of steps S703 and S704. Further, the processor can execute step S705, and the generated alarm can be sent to the network management device through a certain interface.

[0146] 3. The clock circuit can perform... Figure 7 In method one of S702, the frequency offset between at least three clocks in the received clock and the local crystal oscillator is obtained, and these frequency offsets are then sent to the processor. The processor executes the remaining part of method one of S702 to obtain the frequency offset between at least three clocks in the received clock. Then the processor executes S703 and S704. Further, the processor can execute S705, and the generated alarm can be sent to the network management device through an interface.

[0147] It should be noted that any of the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the first network node or controller embodiment provided by this invention, the connection relationship between modules indicates that they have a communication connection, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0148] The steps of the methods or algorithms described in the embodiments of this invention can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), hard disk, portable hard disk, optical disk, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an ASIC.

[0149] Those skilled in the art will recognize that, in one or more of the above examples, the functions described in this invention can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer. The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this invention. It should be understood that the above descriptions are merely specific embodiments of this invention and are not intended to limit the scope of protection of this invention. Any modifications, equivalent substitutions, improvements, etc., made based on the technical solution of this invention should be included within the scope of protection of this invention.

Claims

1. A clock fault locating method, characterized by, include: The network device acquires the frequency offset between at least two clocks and the local clock; If the frequency offset between at least two clocks and the local clock exceeds the frequency offset threshold, the network device determines that the local clock is faulty. If the frequency offset between the first clock in the at least two clocks and the local clock exceeds the frequency offset threshold, and the frequency offset between all other clocks in the at least two clocks except the first clock and the local clock does not exceed the frequency offset threshold, the network device determines that the first clock is faulty.

2. The method of claim 1, wherein, The at least two clocks include three or more clocks.

3. The method according to claim 1 or 2, characterized in that, The frequency offset threshold is ±4.6 parts per million (ppm).

4. The method according to any one of claims 1-3, characterized in that, The network device is a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization.

5. The method according to any one of claims 1-4, characterized in that, Also includes: The network device generates an alarm, which indicates a clock fault source.

6. A network device for locating clock faults, characterized in that, include: The acquisition unit further includes a first determining unit and a second determining unit; wherein, The acquisition unit is used to acquire the frequency offset between at least two clocks and the local clock; The first determining unit is used to determine that the local clock is faulty when the frequency offset between the at least two clocks and the local clock exceeds the frequency offset threshold; The second determining unit is used to determine that the first clock is faulty when the frequency offset between the first clock and the local clock in the at least two clocks exceeds the frequency offset threshold, and the frequency offset between all other clocks in the at least two clocks except the first clock and the local clock does not exceed the frequency offset threshold.

7. The network device according to claim 6, characterized in that, The at least two clocks include three or more clocks.

8. The network device according to claim 6 or 7, characterized in that, The frequency offset threshold is ±4.6 parts per million (ppm).

9. The network device according to any one of claims 6-8, characterized in that, The network device is a device that supports physical layer clock synchronization or a device that supports precise clock protocol synchronization.

10. The network device according to any one of claims 6-9, characterized in that, It also includes an alarm unit for generating an alarm, which indicates a clock fault source.

11. A network device for locating clock faults, characterized in that, It includes an interface, a clock circuit, and a processor. The interface is used to receive at least two clocks, and the clock circuit is used to obtain the frequency offset between the at least two clocks and a local clock. The processor is used for: If the frequency offset between at least two clocks and the local clock exceeds the frequency offset threshold, the local clock is determined to be faulty. If the frequency offset between the first clock in the at least two clocks and the local clock exceeds the frequency offset threshold, and the frequency offset between all other clocks in the at least two clocks except the first clock and the local clock does not exceed the frequency offset threshold, then the first clock in the at least two clocks is determined to be faulty.

12. A computer-readable medium, characterized in that, The computer-readable storage medium stores instructions that, when executed on a processor, cause the computer to perform the following steps: Obtain the frequency offset between at least two clocks and the local clock; If the frequency offset between at least two clocks and the local clock exceeds the frequency offset threshold, the local clock is determined to be faulty. If the frequency offset between the first clock in the at least two clocks and the local clock exceeds the frequency offset threshold, and the frequency offset between all other clocks in the at least two clocks except the first clock and the local clock does not exceed the frequency offset threshold, then the first clock is determined to be faulty.

13. A computer program product, characterized in that, The computer program product includes instructions that, when executed on a processor, cause the network device to perform the method of any one of claims 1-5.

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