CN116566529A

CN116566529A - Time adjustment method, network equipment and system

Info

Publication number: CN116566529A
Application number: CN202210103376.XA
Authority: CN
Inventors: 何涛
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2023-08-08

Abstract

The embodiment of the application provides a time adjustment method which is applied to network equipment in the communication field, including client terminal equipment of ATN, PTN and router product line, or network equipment of a core layer, a convergence layer and an access layer in a communication network. The method comprises the following steps: the first network device obtains the deviation of the system frequency of the first network device and the system frequency of the upstream time synchronization device, obtains the time deviation according to the frequency deviation and adjusts the system time. The time deviation can be reduced, and the time synchronization performance of the network equipment can be improved. The method can also improve the time delay measurement precision of the business messages such as the IFIT and the like, and meet the high requirement of time synchronization performance.

Description

Time adjustment method, network equipment and system

Technical Field

The present disclosure relates to the field of communications technologies, and in particular, to a time adjustment method, a network device, and a system.

Background

The flow following detection technology (in-situ flow information telemetry, IFIT) is a detection technology for directly detecting performance indexes such as time delay, packet loss, jitter and the like of a network by carrying out characteristic marking on real service flows of the network. The IFIT delay measurement function has high requirements on time synchronization performance between devices.

The accurate time protocol (precision time protocol, PTP) specifies a time adjustment method between communication devices, specifically, by sending PTP messages between the devices, the time adjustment is periodically performed by using a filtering algorithm, so as to achieve the synchronization between the system time of the network device and the system time of the upstream time synchronization device.

However, as the filtering modulation frequency is higher, the noise filtering capability of the communication device is poorer, and the time deviation of each adjustment is limited due to the bandwidth of the time adjustment loop, the time deviation of the system time of the communication device compared with the system time of the upstream time synchronization device will jump with time, for example, a sawtooth wave is presented, the amplitude peak value of the sawtooth wave is high, the time synchronization performance is poorer, and the higher requirements of the time synchronization performance such as the IFIT technology cannot be met.

Disclosure of Invention

In view of this, the embodiments of the present application provide a time adjustment method and a network device, which are used to improve time synchronization performance of the network device.

In a first aspect, the present application provides a time adjustment method, including: the method comprises the steps that a first network device obtains frequency deviation, wherein the frequency deviation is the deviation between the system frequency of the first network device and the system frequency of a second network device, and the second network device is upstream time synchronization equipment of the first network device; the first network equipment obtains time deviation according to the frequency deviation, wherein the time deviation is generated by the frequency deviation of the first network equipment and the second network equipment; and the first network equipment adjusts the system time according to the time deviation.

Based on the scheme provided by the application, as the frequency of the first network equipment is not synchronous with that of the upstream time synchronization equipment, frequency deviation can be generated, and then time deviation can be continuously generated, the first network equipment obtains the frequency deviation between the first network equipment and the upstream time synchronization equipment, calculates the time deviation caused by the frequency deviation according to the frequency deviation and adjusts the system time, so that the time deviation caused by the frequency deviation can be reduced, and the time synchronization performance is improved.

In a possible implementation manner of the first aspect, the obtaining, by the first network device, a time offset according to the frequency offset includes: the first network device obtains time deviation according to the frequency deviation and a first period, wherein the time deviation is generated by the first network device and the second network device in the first period, and the first period is a period of adjusting system time according to the time deviation.

According to the scheme, the time deviation generated based on the frequency deviation is periodically adjusted based on the first period, and the time synchronization performance of the first network equipment is improved.

In a possible implementation manner of the first aspect, the first period is smaller than the second period, and the second period is a period during which the first network device adjusts the system time according to a filtering algorithm, where the filtering algorithm is a proportional-differential integral control algorithm.

According to the scheme, the first period for adjusting the time deviation generated based on the frequency deviation is smaller than the second period for adjusting based on the filtering algorithm, so that the amplitude value of the time deviation sawtooth wave can be reduced, and the overall time synchronization performance is improved.

In a possible implementation manner of the first aspect, the obtaining, by the first network device, a frequency deviation includes: the first network device obtains N time delay data, wherein the N time delay data are used for indicating message transmission time delay between the first network device and the second network device, and N is a positive integer greater than or equal to 2; and the first network equipment obtains the frequency deviation according to the N delay data.

In a possible implementation manner of the first aspect, the first network device receives the frequency deviation sent by the third network device.

In a possible implementation manner of the first aspect, the N delay data includes first delay data and second delay data, and the obtaining the N delay data includes: the first network equipment obtains the first delay data according to the first message transmission delay; the first network device obtains the second time delay data according to the second message transmission time delay and the adjustment value of the system time in the specific time length, wherein the adjustment value of the system time in the specific time length is the adjustment value of the system time between the time corresponding to the first time delay data and the time corresponding to the second time delay data.

According to the scheme provided by the application, if time adjustment exists in the specific time length corresponding to the N time delay data, the time delay data are required to be compensated to obtain the time delay data, the time delay data in the time delay array can be unified to the same reference time through compensation and used for calculating the frequency deviation, and the accuracy of calculating the frequency deviation is improved.

In a possible implementation manner of the first aspect, the adjustment value of the system time includes an adjustment value for adjusting the system time according to a filtering algorithm.

In a possible implementation manner of the first aspect, the adjustment value of the system time includes the adjustment value for adjusting the system time according to the time deviation.

In a possible implementation manner of the first aspect, the first network device adjusts the system time according to the filtering algorithm and adjusts the system time according to the time deviation within a specific duration, so that the adjustment value of the system time according to the filtering algorithm and the adjustment value of the system time according to the time deviation are required to be used for compensating the time delay to obtain the time delay data.

In a possible implementation manner of the first aspect, any one of the N delay data is a packet transmission delay between the first network device and the second network device.

If the first network device does not perform time adjustment between the times corresponding to any two time delay data in the N time delay data, the N time delay data are all message transmission time delays between the first network device and the second network device, and it is required to be noted that the N time delay data are obtained based on different time synchronization messages.

In a possible implementation manner of the first aspect, the obtaining, by the first network device, the frequency deviation according to the N delay data includes: and the first network equipment processes the N time delay data according to a least square method to obtain the frequency deviation and the error, wherein the error is smaller than or equal to a first threshold value.

According to the scheme provided by the application, when the first network equipment estimates the frequency deviation, linear fitting can be performed on the time-lapse data, and various linear fitting methods, such as least square method, average linear fitting and the like, are adopted, and the method is not particularly limited. When the error corresponding to the frequency deviation meets the first threshold requirement, the frequency deviation is an effective value, and the accuracy of time synchronization can be improved through the design of the error limit value.

In a possible implementation manner of the first aspect, the obtaining, by the first network device, the frequency deviation according to the N delay data includes: and in a third period, the first network device obtains the frequency deviation according to the N pieces of delay data, wherein the third period is the obtaining period of the frequency deviation.

According to the scheme provided by the application, the system time can be adjusted according to the calculated frequency deviation in the third period, and after the frequency deviation is recalculated in the third period, the frequency deviation is updated, so that the time synchronization performance is further improved.

In a possible implementation manner of the first aspect, the N is less than or equal to a second threshold value, and the second threshold value is greater than or equal to 3.

According to the scheme provided by the application, the more the number of time delay data used for calculating the frequency deviation is, the higher the calculation accuracy is, and the more complex the calculation is. The number of the limited time delay data is smaller than or equal to a second threshold value, the calculation complexity and the precision of the frequency deviation can be controlled through setting of the second threshold value, and the calculated amount is controlled to be in a reasonable range while the calculation precision is ensured.

In a possible implementation manner of the first aspect, the first network device is a network device that does not support frequency adjustment.

The scheme provided by the application can be applied to network equipment which does not support frequency adjustment, and time deviation is reduced.

In a possible implementation manner of the first aspect, the first network device is a network device supporting frequency adjustment.

The scheme provided by the application can also be applied to network equipment supporting frequency adjustment and is used for reducing time deviation.

In a possible implementation manner of the first aspect, the method further includes: and if the frequency deviation is greater than or equal to a third threshold value, the first network equipment switches the frequency source to the second network equipment.

According to the scheme provided by the application, if the first network equipment is provided with the frequency adjustment loop on the hardware structure, frequency source cutting can be performed when certain conditions (such as frequency deviation is larger than a third threshold value) are met, time dyssynchrony is fundamentally avoided by correcting time-frequency different sources, and time synchronization performance of the network equipment can be remarkably improved.

In a second aspect, the present application provides a network device comprising: an obtaining unit, configured to obtain a frequency deviation, where the frequency deviation is a deviation between a system frequency of the first network device and a system frequency of a second network device, and the second network device is an upstream time synchronization device of the first network device; the obtaining unit is further configured to obtain a time offset according to the frequency offset, where the time offset is a time offset generated by the frequency offset by the first network device and the second network device; and the adjusting unit is used for adjusting the system time according to the time deviation.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: and obtaining time deviation according to the frequency deviation and a first period, wherein the time deviation is generated by the first network equipment and the second network equipment in the first period, and the first period is a period of the system time adjusted by the adjusting unit according to the time deviation.

In a possible implementation manner of the second aspect, the first period is smaller than the second period, and the second period is a period during which the network device adjusts the system time according to a filtering algorithm, and the filtering algorithm is a proportional-differential integral control algorithm.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: the method comprises the steps of obtaining N time delay data, wherein the N time delay data are used for indicating message transmission time delay between first network equipment and second network equipment, and N is a positive integer greater than or equal to 2; and obtaining the frequency deviation according to the N time delay data.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: acquiring the first delay data according to the first message transmission delay; and acquiring the second time delay data according to the second message transmission time delay and the adjustment value of the system time in the specific time length, wherein the adjustment value of the system time in the specific time length is the adjustment value of the system time between the time corresponding to the first time delay data and the time corresponding to the second time delay data.

In a possible implementation manner of the second aspect, the adjustment value of the system time includes an adjustment value for adjusting the system time according to a filtering algorithm.

In a possible implementation manner of the second aspect, the adjustment value of the system time includes the adjustment value for adjusting the system time according to the time deviation.

In a possible implementation manner of the second aspect, any one of the N latency data is a packet transmission latency between the first network device and the second network device.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: and processing the N time delay data according to a least square method to obtain the frequency deviation and the error, wherein the error is smaller than or equal to a first threshold value.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: and in a third period, the frequency deviation is obtained according to the N time delay data, and the third period is the obtaining period of the frequency deviation.

In a possible implementation manner of the second aspect, the N is less than or equal to a second threshold value, and the second threshold value is greater than or equal to 3.

In a possible implementation manner of the second aspect, the first network device is a network device that does not support frequency adjustment.

In a possible implementation manner of the second aspect, the first network device is a network device supporting frequency adjustment.

In a possible implementation manner of the second aspect, the network device further includes: and the switching unit is used for switching the frequency source to the second network equipment if the frequency deviation is larger than or equal to a third threshold value.

In a third aspect, the present application provides a network device, including: one or more processors and memory; wherein the memory has stored therein computer readable instructions; the one or more processors read the computer readable instructions to cause the network device to perform the method of the first aspect and any of the various possible implementations described above.

In a fourth aspect, the present application provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method according to the first aspect and any of the various possible implementations.

In a fifth aspect, the present application provides a computer readable storage medium comprising instructions, characterized in that the instructions, when run on a computer, cause the computer to perform the method according to the first aspect and any of the various possible implementations.

In a sixth aspect, the present application provides a chip comprising a processor. The processor is configured to read and execute a computer program stored in the memory to perform the method in any of the possible implementations of any of the aspects described above. Optionally, the chip includes a memory, and the memory and the processor are connected to the memory through a circuit or a wire. Further optionally, the chip further comprises a communication interface, and the processor is connected to the communication interface. The communication interface is used for receiving data and/or information to be processed, and the processor acquires the data and/or information from the communication interface, processes the data and/or information and outputs a processing result through the communication interface. The communication interface may be an input-output interface.

Technical effects of any implementation manner of the second aspect, the third aspect, the fourth aspect, the fifth aspect or the sixth aspect may refer to technical effects of corresponding implementation manners of the first aspect, which are not described herein.

According to the time adjustment method, the first network equipment obtains the time deviation through the frequency deviation, adjusts the system time, can reduce the time deviation generated by the frequency deviation, and improves the time synchronization performance. Taking CPE communication equipment without a hardware adjusting loop as an example, TE performance is improved by more than 5 times.

For the equipment supporting the frequency adjustment loop and the time adjustment loop on the hardware of the core layer, the convergence layer or the access layer in the communication network, whether the frequency and the time are different or not can be effectively detected, and the IFIT time synchronization performance of scenes of the different frequency and the time can be improved. Because the time adjustment method provided by the application has no requirement on the time source or the frequency source of the network equipment, the clock tracking paths of thousands of equipment in the whole networking are not required to be checked, the deployment difficulty and the operation and maintenance difficulty of the IFIT time synchronization characteristic are reduced, more application scenes can be supported, and the operation and maintenance efficiency is improved.

Drawings

Fig. 1 is an application scenario architecture diagram of a time adjustment method provided in an embodiment of the present application;

fig. 2 is another application scenario structure diagram of the time adjustment method provided in the embodiment of the present application;

FIG. 3 is a schematic diagram of the IFIT delay measurement principle;

FIG. 4 is a schematic diagram of an embodiment of a time adjustment method according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a time-offset sawtooth;

FIG. 6 is another schematic diagram of a time-offset sawtooth in an embodiment of the present application;

FIG. 7 is another schematic diagram of a time-offset sawtooth in an embodiment of the present application;

FIG. 8 is a schematic diagram of one embodiment of a network device according to an embodiment of the present application;

fig. 9 is a schematic diagram of another embodiment of a network device according to an embodiment of the present application.

Detailed Description

The embodiment of the application provides a time adjustment method, network equipment and a system, which are used for improving the time synchronization performance of the network equipment.

Embodiments of the present application will now be described with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some, but not all embodiments of the present application. As one of ordinary skill in the art can appreciate, with the development of technology and the appearance of new scenes, the technical solutions provided in the embodiments of the present application are applicable to similar technical problems.

The terms first, second and the like in the description and in the claims of the present application and in the above-described figures, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments described herein may be implemented in other sequences than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or modules is not necessarily limited to those steps or modules that are expressly listed or inherent to such process, method, article, or apparatus. The naming or numbering of the steps in the present application does not mean that the steps in the method flow must be executed according to the time/logic sequence indicated by the naming or numbering, and the execution sequence of the steps in the flow that are named or numbered may be changed according to the technical purpose to be achieved, so long as the same or similar technical effects can be achieved.

The following describes an application scenario architecture of the time adjustment method in the embodiment of the present application, and please refer to fig. 1 and fig. 2, which are diagrams of the application scenario architecture of the time adjustment method in the embodiment of the present application.

As shown in fig. 1, an application scenario of the time adjustment method provided in the embodiment of the present application includes a network device NE-1 and a network device NE-2, where NE-1 and NE-2 may be directly connected, or may be connected through other network devices. Wherein NE-1 is an upstream time synchronization device of NE-2, and the specific device type is not limited. NE-2 is a device which does not support frequency synchronization devices in hardware, such as flexible transmission devices (agile transport network, ATN), packet transport networks (packet transport network, PTN), customer premise equipment (customer premises equipment, CPE) and the like, and devices such as direct digital frequency synthesizers (direct digital synthesizer, DDS) and the like. In the scenario illustrated in FIG. 1, a time synchronization loop is included for time synchronization between NE-2 and NE-1.

As shown in fig. 2, another application scenario of the time adjustment method provided in the embodiment of the present application includes network equipment NE-1, network equipment NE-2 and network equipment NE-3, where NE-3 and NE-1 may be directly connected, or may be connected through other network equipment, and similarly, NE-3 and NE-2 may be directly connected, or may be connected through other network equipment. NE-3 is a hardware-supported frequency synchronization device. Where NE-1 is the frequency tracking source of NE-3, the system clock frequency of NE-3 is synchronized with the system time frequency of NE-1. NE-2 is an upstream time synchronization device of NE-3, and NE-3 performs time synchronization with NE-2 by receiving and transmitting time synchronization messages.

In a communication network device, frequency synchronization is a precondition of time synchronization, and frequency synchronization performance of a system clock in the device affects time synchronization performance, and when the frequency is not synchronized, the time synchronization performance is poor, and specific analysis is performed with reference to fig. 1 and 2.

Based on the application scenario of fig. 1 showing different sources of time and frequency, the network device NE-2 performs time synchronization by transceiving time synchronization messages with the upstream time synchronization device NE-1. NE-1 marks a time stamp T1 at the sending time of the time synchronization message, and NE-2 marks a time stamp T2 at the receiving time of the time synchronization message. The time stamp T2 is a clock mark based on free oscillation of the local crystal oscillator of the NE-2, the time stamp T1 is a system clock mark based on the NE-1, and the asynchronous system clock of the NE-1 and the clock of the free oscillation of the local crystal oscillator of the NE-2 can reduce the accuracy of time delay data calculated based on the time stamp T1 and the time stamp T2, so that the time synchronization performance of the NE-2 is poor.

Based on the application scenario of the different sources of time and frequency shown in fig. 2, it should be noted that the different sources of time and frequency of NE-3 include:

1) The frequency source of NE-3 is derived from the clock source communication building timing supply system (building integrated timing supply, BITS) (since the NE-1 frequency source is derived from the clock source BITS), but the time source of NE-3 is derived from NE-2, so the frequency and time of NE-3 are not of the same origin.

2) The frequency source of NE-3 is derived from NE-1 (the frequency source of NE-1 is not derived from BITS), but the time source of NE-3 is derived from clock source BITS (since the time source of NE-2 is derived from BITS), thus the frequency and time of NE-3 are not homologous.

3) The frequency source of NE-3 is derived from NE-1, but the time source is derived from NE-2, the frequency source of NE-1 and the time source of NE-2 are not BITS, and therefore, the frequency and time sources of NE-3 are different.

From the above situations, it is clear that although the network equipment NE-3 has a time synchronization loop and also has a frequency synchronization loop, the frequency source is always present, but the frequency source and the time source are different, and in addition, the network equipment may lose the frequency source which is normally tracked, and the equipment is from active to passive.

The network equipment NE-3 performs time synchronization by sending and receiving time synchronization messages with the upstream time synchronization equipment NE-2. NE-2 marks a time stamp T1 at the sending time of the time synchronization message, and NE-3 marks a time stamp T2 at the receiving time of the time synchronization message. The time stamp T2 is a system clock mark based on the NE-1, the time stamp T1 is a system clock mark based on the NE-2, and the system clock of the NE-1 is not synchronous with the system clock of the NE-2, so that the accuracy of time delay data calculated based on the time stamp T1 and the time stamp T2 is reduced, and the time synchronization performance of the NE-3 is poor.

In some specific service scenarios, the time synchronization performance requirement for the network device is higher, for example, the time delay measurement scenario of the flow following detection technology (in-situ flow information telemetry, IFIT), which is a detection technology for directly detecting performance indexes such as time delay, packet loss, jitter and the like of the network by performing feature labeling on the real service flow of the network. The higher the network device time synchronization accuracy, the more accurate the IFIT delay measurement.

Referring to fig. 3 for a brief description of the IFIT delay measurement principle, an ingress (ingress) end, NE1 performs delay dyeing on one of the messages of the detected traffic stream in the present period according to the measurement period, records ingress time stamps T1 and T3 of the message, and reports the message to the centralized computing unit, and an egress (egress) end records egress time stamps T2 and T4 of the delay dyed messages of the detected traffic stream in each period according to the same period of the ingress end, and reports the message to the centralized computing unit. The centralized calculation unit calculates the unidirectional time delay of the service flow in two directions of the period i according to the information reported by the ingress end and the egress end, the unidirectional time delay of the NE1 to the NE2 is T2-T1, the unidirectional time delay of the NE2 to the NE1 is T4-T3, when the detected service flow is in the bidirectional same path, the bidirectional time delay of the service flow period i can be calculated and is (T2-T1) + (T4-T3), and the calculation method of the time delay is not limited in the embodiment of the application.

To ensure the synchronization of the dyeing cycles at the ingress (ingress) and egress (egress) ends, a time synchronization mechanism needs to be deployed, and the existing time synchronization mechanism is usually based on a precision time protocol (precision time protocol, PTP) protocol, and the time adjustment is performed by a filtering algorithm. It should be noted that, the time adjustment method provided in the embodiment of the present application does not limit the time synchronization protocol observed by the network device, and may send a time synchronization message to obtain a time stamp based on the PTP protocol, or may obtain time stamp information based on other time synchronization protocols, for example, NTP protocol. The filtering adjustment is that the device uses a phase-locked loop to carry out filtering processing to realize time adjustment of time synchronization according to the required bandwidth based on a proportional-differential integral (proportion integral differential, PID) control principle, so that service noise of the network device can be removed. Because the higher the filtering modulation frequency is, the worse the noise filtering capability of the communication equipment is, and the time deviation of each adjustment is limited, the time deviation of the system time of the communication equipment compared with the system time of the upstream time synchronization equipment will jump with time, for example, a sawtooth wave is presented, the amplitude peak value of the sawtooth wave is high, the time synchronization performance is poor, and the higher requirements of the time synchronization performance such as the IFIT technology cannot be met.

In view of this, the embodiments of the present application provide a time adjustment method and a network device, which are used to reduce time deviation and improve time synchronization performance of the network device.

Referring to fig. 4, an embodiment of the present application proposes a method 400 for time adjustment to improve time synchronization performance. The method 400 may be applied to the scenario shown in fig. 1 or fig. 2, where in the application scenario shown in fig. 1, the first network device corresponds to NE-2 shown in fig. 1, and the second network device corresponds to NE-1 shown in fig. 1; in the application scenario shown in fig. 2, the first network device corresponds to NE-3 shown in fig. 1, the second network device corresponds to NE-2 shown in fig. 1, and the method 400 includes S401-S403.

It should be noted that, the first network device may perform time adjustment based on an existing time synchronization protocol, for example, for a network device that complies with PTP protocol, the system time may be adjusted by a filtering algorithm (hereinafter referred to as filtering adjustment).

S401, the first network equipment obtains frequency deviation.

The frequency deviation is a deviation of a system frequency of the first network device from a system frequency of the second network device, which is an upstream time synchronization device of the first network device.

As a specific implementation manner, the manner in which the first network device obtains the frequency deviation includes the following two manners:

mode 1: the first network device receives the frequency offset from the third network device.

Mode 2: the first network device obtains a frequency deviation according to the N delay data. The method specifically comprises the following steps: the first network device obtains N time delay data, N is a positive integer greater than or equal to 2, and the first network device obtains frequency deviation according to the N time delay data.

The first network device can calculate the time delay according to the time synchronization message received and transmitted between the first network device and the second network device, and N time delay data are obtained according to the time delay.

It should be noted that the first network device may perform filtering adjustment on the system time, specifically, the first network device may perform filtering adjustment periodically according to a time interval of filtering adjustment by using a second-order phase-locked loop algorithm according to time stamps T1, T2, T3 and T4 of the PTP packet, and the time interval of filtering adjustment is, for example, 5 seconds, where the time interval of filtering adjustment may support configuration, and the time interval of filtering adjustment is related to a phase-locked loop bandwidth, and specific values are not limited. Illustratively, the NE-2 device performs filtering adjustments every 5 seconds using a second order phase locked loop algorithm based on the time stamps T1, T2, T3, and T4 of the PTP messages.

As a specific implementation manner, based on whether the system time is adjusted in the process of acquiring N pieces of time delay data, there are various methods for acquiring N pieces of time delay data, including: in the mode 1, any one of the n delay data is a packet transmission delay between the first network device and the second network device. That is, the first network device does not perform time adjustment in the process of acquiring N pieces of time delay data, and each piece of time delay data is directly obtained by calculating the time stamp information.

The first network device can calculate the time delay according to the time synchronization message received and transmitted between the first network device and the second network device, namely, the time stamp information is periodically obtained by stamping the time synchronization message at the sending time and the receiving time, and the time delay is obtained according to the time stamp information. The first network device starts an IFIT time synchronization function, acquires one time of time stamp information (T1, T2, T3 and T4), and acquires time delay according to the time stamp information. Illustratively, the NE-2 device IFIT time synchronization function is enabled to obtain the time stamp information once per second. It should be noted that, the calculation methods of the time synchronization message transmission delay between the first network device and the second network device are various, including any one of the following: T2-T1, or T4-T3, or [ (T4-T3) + (T2-T1) ]/2, the specific calculation method is not limited herein. In addition, the sending rate of the time synchronization message is not limited.

In mode 2, since the first network device may adjust the system time based on the filter adjustment or the time deviation obtained based on the frequency deviation in the embodiment of the present application in the process of calculating the time delay. Therefore, in order to calculate the frequency deviation, the original delay needs to be compensated. The N time delay data comprise first time delay data and second time delay data, and the first network equipment obtains the first time delay data according to the first message transmission time delay; the first network equipment obtains second delay data according to second message transmission delay and an adjustment value of system time in a specific time length, wherein the adjustment value of the system time in the specific time length is an adjustment value of the system time between the time corresponding to the first delay data and the time corresponding to the second delay data. Here, the first delay data is obtained directly according to the first packet transmission delay, and the specific duration refers to a time period between a time corresponding to the first delay data and a time corresponding to the second delay data, and since the system time is adjusted, the second delay data needs to be compensated according to the adjustment value, so that the first delay data and the second delay data can be used together for performing offset deviation calculation. The N delay data used for frequency offset calculation may be regarded as transmission delay at the same reference time, that is, the influence of the first network device on the time adjustment of the system time in the time period corresponding to all the delay data is eliminated. If the time synchronization adjustment is performed after the time corresponding to the first time delay and before the time corresponding to the second time delay, the second time delay data recorded in the time delay array is the second time delay which is compensated according to the time adjustment. Further, if multiple time adjustments are performed between the time corresponding to the first time delay and the time corresponding to the third time delay, third time delay data recorded in the time delay array is the time delay after the third time delay is accumulated and compensated according to multiple adjustment values.

The system time adjustment value includes an adjustment value for adjusting the system time according to a filtering algorithm, or an adjustment value for adjusting the system time according to a time deviation, or both an adjustment value for adjusting the system time according to a filtering algorithm and an adjustment value for adjusting the system time according to a time deviation.

For example, the time deviation adjustment value is reversely compensated to the time delay by accumulation mode to obtain time delay data, for example, to (T2-T1), namely, the time delay data (T2-T1) calculated by each acquired time stamp is added with the accumulated result of the time deviation adjustment value to obtain the time delay data, and the time delay data is stored in an array for calculating the subsequent frequency deviation.

The first network device obtains the frequency deviation according to the N delay data, and the method comprises the following steps: and the first network equipment processes the N time delay data according to a least square method to obtain the frequency deviation and the error, wherein the error is smaller than or equal to a first threshold value. It should be noted that, the first network device may calculate the frequency deviation by linear fitting based on the N delay data, and the linear fitting method is various, for example, a least square method, an average linear fitting method, and the like, which is not limited in particular. For example, the first network device performs linear fitting on the N delay data according to a least square method to obtain a frequency deviation. And the first network equipment carries out linear fitting on the time delay array according to a least square method to obtain frequency deviation and an error corresponding to the frequency deviation, wherein the error is smaller than or equal to a first threshold value. The first threshold may be configured according to specific requirements, such as the three sigma (3 sigma ) principle, and specific values are not limited herein. And when the error is smaller than or equal to the first threshold value, determining that the frequency deviation is effective, and if the error is larger than the first threshold value, determining that the frequency deviation is ineffective, and calculating after acquiring the time delay data again.

In a specific implementation manner, the N delay data may be delay data subjected to data filtering, for example, deleting delay data with significant errors, etc., which may be specifically implemented by various existing methods, which are not described herein.

The first network device obtaining the frequency deviation according to the N delay data includes: and in a third period, the first network equipment obtains the frequency deviation according to the N time delay data, wherein the third period is the obtaining period of the frequency deviation. The third period may be, for example, 30 seconds, 1 minute, or the like, and specific values are not limited. It should be noted that, when the third period is exceeded, the first network device may retrieve the frequency deviation and use it for subsequent calculation of the time deviation.

It will be appreciated that the amount of delay data is related to the accuracy, computational complexity and real-time nature of the frequency deviation estimation, and configuration may be supported. The N is less than or equal to a second threshold, the second threshold being greater than or equal to 3. Illustratively, the delay data is recorded by a delay array, the second threshold is 30, and the number of delay data in the delay array is greater than or equal to 2 and less than or equal to 30.

S402, the first network equipment obtains time deviation according to the frequency deviation.

The first network device can calculate the time deviation of the first network device due to the frequency deviation in a period of time according to the frequency deviation. Optionally, the first network device obtains a time offset according to the frequency offset and a first period, where the time offset is a time offset generated by the frequency offset in the first period by the first network device and the second network device. The first period is a period of system time adjusted by the first network device according to the time deviation.

In a specific implementation, the first network device multiplies the frequency deviation by the first period to obtain the time deviation.

In a specific implementation manner, the first period is smaller than the second period, and the second period is a period in which the first network device adjusts the system time according to a filtering algorithm, and the filtering algorithm is a proportional-differential integral control algorithm. Illustratively, the first period is 1 second and the second period is 5 seconds. Optionally, the first period is greater than or equal to a time interval for acquiring the time stamp and is less than the second period. Optionally, the specific value of the first period supports configuration, and the timer is related to a timer supported by hardware of the first network device, and the timer includes a 1s timer or a 100ms timer.

S403, the first network equipment adjusts the system time according to the time deviation.

The first network device adjusts the system time according to the calculated time offset, optionally determines a time point of modulating the system time according to a first period, and adjusts the system time at the time point, for example, the first period is 5 seconds.

For example, a fast adjustment of the time offset introduced by the frequency offset is performed, for example, the adjustment interval is 1 second, the adjustment value of the time offset is issued to the real-time clock (RTC) every second to adjust the system time of the first network device, and the time offset is additionally compensated back into the delay data by means of accumulation.

In a specific implementation, if the time point is also the time point corresponding to the filter adjustment (which may be determined according to the second period), the time adjustment is performed at the time point according to the filter adjustment, the time adjustment is performed according to the time deviation, or the time adjustment is performed according to the time deviation and the filter adjustment time difference, which is not limited herein.

Further, if the first network device is a network device supporting frequency adjustment as shown in fig. 2, the method further includes: and if the frequency deviation is greater than or equal to a third threshold value, the first network equipment switches the frequency source to the second network equipment. The value of the third threshold may be set according to the use requirement, and the configuration is supported, where the value may relate to the maximum frequency deviation range normally supported by the service in the application scenario, and when the frequency deviation exceeds the third threshold, the service may be abnormal, and the specific value of the third threshold is not limited herein. Alternatively, frequency switching may be performed in conjunction with a clock-full network topology, with customer requirements being obtained. Illustratively, the frequency source of NE-3 is switched from NE-1 to NE-2, i.e. the frequency source is switched to the same path as the PTP message, so as to realize frequency and time homology, finally improve the IFIT time synchronization performance, thoroughly eliminate the sawtooth wave of TE, and not just reduce the amplitude value of the sawtooth wave. According to the time adjustment method provided by the embodiment of the application, the time deviation is obtained through the frequency deviation, and the system time is adjusted, so that the time deviation generated by the frequency deviation can be reduced, and the time synchronization performance is improved.

Further, due to the presence of frequency offset, the time deviation caused by the frequency offset between two continuous filtering adjustments can be linearly increased, and referring to fig. 5, the sawtooth amplitude value is high, the time synchronization performance is poor, and the high requirement of the IFIT technology on the time synchronization precision in the time delay measurement cannot be met. In the time adjustment method provided by the embodiment of the application, if the first period is smaller than the second period, that is, the first network device adjusts the time deviation caused by the frequency deviation through adjusting the higher frequency compared with the filtering, the amplitude value of the sawtooth wave can be reduced, the time synchronization performance of the first network device is improved, and the high requirement of the IFIT technology and the like on the time synchronization precision in the time delay measurement is met. The following describes a change situation of the time deviation in the time adjustment method provided in the present application with reference to fig. 6 and 7.

The black solid line 601 in the figure represents the time difference between the first network device and the second network device with time, the gray solid line represents the adjustment of the system time by the first network device, including the filter adjustment 6021 and the time adjustment according to the time deviation (in this embodiment, the first period of the time adjustment according to the time deviation is smaller than the second period of the filter adjustment, which is called fast adjustment for convenience of description), and it is seen that the time deviation between the first network device and the second network device decreases when the time adjustment is performed, and the time difference between the first network device and the second network device entirely exhibits a saw-tooth waveform. After the IFIT time synchronization function of the first network device is started, timestamp information can be obtained and a time delay between the first network device and the second network device can be calculated, and five-pointed star 603 in fig. 6 represents time delay data with noise, and the time delay data is subjected to time compensation, including time compensation 6041 based on filtering adjustment and time compensation 6042 based on rapid adjustment. Frequency deviation is calculated by linear fitting technique due to noise in the time delay data. According to the time adjustment method, the network equipment can reduce the amplitude value of the sawtooth wave by quickly adjusting the time, as shown in the figure, the point A is reduced to the point B, the time synchronization precision is improved, and the high requirement of IFIT and other technologies on time synchronization can be better met. In the time adjustment method provided in the embodiment of the present application, the time interval of the fast adjustment is smaller than the time interval of the filter adjustment, and in a possible implementation manner, the time interval of the filter adjustment and the time interval of the fast adjustment are not in an integer multiple relationship, for example, referring to fig. 7, at the time of the fast adjustment (e.g. t 1), the first network device performs the fast adjustment according to the time deviation of the fast adjustment. At the time of the filter adjustment (e.g., t 2), the first network device performs the filter adjustment to achieve time synchronization. It will be appreciated that the filtering adjustment and the fast adjustment are performed independently of each other and do not affect each other, wherein the filtering adjustment may remove traffic noise of the network device, and the fast adjustment is used to remove noise caused by frequency deviation. Accordingly, the time adjustment is supplemented in the time delay array, including time compensation based on rapid adjustment and time compensation based on filtering adjustment. After the time adjustment method is quickly adjusted, the amplitude value of the visible time deviation sawtooth wave is reduced from the point A to the point B, the time synchronization precision is improved, and the high requirement of IFIT and other technologies on time synchronization can be better met.

Having described the time adjustment method provided in the present application, the following describes a network device implementing the time adjustment method, and please refer to fig. 8, which is a schematic diagram of an embodiment of a network device in an embodiment of the present application.

The network device includes:

an obtaining unit 801, configured to obtain a frequency deviation, where the frequency deviation is a deviation between a system frequency of the first network device and a system frequency of a second network device, and the second network device is an upstream time synchronization device of the first network device; the obtaining unit 801 is further configured to obtain a time offset according to the frequency offset, where the time offset is a time offset generated by the frequency offset by the first network device and the second network device; an adjusting unit 802, configured to adjust the system time according to the time deviation.

Alternatively, the obtaining unit 801 is specifically configured to: and obtaining time deviation according to the frequency deviation and a first period, wherein the time deviation is generated by the first network equipment and the second network equipment in the first period, and the first period is a period of the system time adjusted by the adjusting unit according to the time deviation.

Optionally, the first period is smaller than the second period, the second period is a period for adjusting the system time according to a filtering algorithm, and the filtering algorithm is a proportional-differential integral control algorithm.

Alternatively, the obtaining unit 801 is specifically configured to: the method comprises the steps of obtaining N time delay data, wherein the N time delay data are used for indicating message transmission time delay between first network equipment and second network equipment, and N is a positive integer greater than or equal to 2; and obtaining the frequency deviation according to the N time delay data.

Alternatively, the obtaining unit 801 is specifically configured to: acquiring the first delay data according to the first message transmission delay; and acquiring the second time delay data according to the second message transmission time delay and the adjustment value of the system time in the specific time length, wherein the adjustment value of the system time in the specific time length is the adjustment value of the system time between the time corresponding to the first time delay data and the time corresponding to the second time delay data.

Optionally, the adjustment value of the system time includes an adjustment value that adjusts the system time according to a filtering algorithm.

Optionally, the adjustment value of the system time includes the adjustment value of the system time according to the time deviation.

Optionally, any one of the N delay data is a packet transmission delay between the first network device and the second network device.

Alternatively, the obtaining unit 801 is specifically configured to: and processing the N time delay data according to a least square method to obtain the frequency deviation and the error, wherein the error is smaller than or equal to a first threshold value.

Alternatively, the obtaining unit 801 is specifically configured to: and in a third period, the frequency deviation is obtained according to the N time delay data, and the third period is the obtaining period of the frequency deviation.

Optionally, the N is less than or equal to a second threshold, and the second threshold is greater than or equal to 3.

Optionally, the first network device is a network device that does not support frequency adjustment.

Optionally, the first network device is a network device supporting frequency adjustment.

Optionally, the network device further includes: and a switching unit 803, configured to switch the frequency source to the second network device if the frequency deviation is greater than or equal to a third threshold.

The network device provided in the embodiment of the present application is used to implement the time adjustment method described in the foregoing embodiment, and specific implementation processes and beneficial effects are not described herein. It should be understood that the above division of the units of the network is merely a division of a logic function, and may be fully or partially integrated into a physical entity or may be physically separated when actually implemented. And these units may all be implemented in the form of software calls through the processing element; or can be realized in hardware; it is also possible that part of the units are implemented in the form of software, which is called by the processing element, and part of the units are implemented in the form of hardware.

For example, the above units may be one or more integrated circuits configured to implement the above methods, such as: one or more specific integrated circuits (application specific integrated circuit, ASIC), or one or more microprocessors (digital singnal processor, DSP), or one or more field programmable gate arrays (field programmable gate array, FPGA), or the like. For another example, when a unit above is implemented in the form of a processing element scheduler, the processing element may be a general purpose processor, such as a central processing unit (central processing unit, CPU) or other processor that may invoke the program. For another example, the units may be integrated together and implemented in the form of a system-on-a-chip (SOC).

Referring to fig. 9, another embodiment of a network device in an embodiment of the present application is shown.

The network device provided in this embodiment may be an ATN, a PTN, or a CPE, or a network device of a core layer, a convergence layer, or an access layer in a communication network, etc. The specific device configuration is not limited in the embodiment of the present application.

The network device 900 may vary widely in configuration or performance and may include one or more processors 901 and memory 902, where the memory 902 stores programs or data.

The memory 902 may be volatile storage or nonvolatile storage. Optionally, the processor 901 is one or more central processing units (central processing unit, CPU), which may be a single core CPU or a multi-core CPU. Processor 901 may be in communication with memory 902 and execute a series of instructions in memory 902 on network device 900.

The network device 900 also includes one or more wired or wireless network interfaces 903, such as an ethernet interface.

Optionally, although not shown in fig. 9, network device 900 may also include one or more power sources; the input/output interface may be used to connect a display, a mouse, a keyboard, a touch screen device, a sensing device, or the like, and the input/output interface may be an optional component, may or may not be present, and is not limited herein.

The flow executed by the processor 901 in the network device 900 in this embodiment may refer to the method flow described in the foregoing method embodiment, and will not be described herein. It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.

In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a storage medium, including several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The above embodiments are merely for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims

1. A time adjustment method, comprising:

the method comprises the steps that a first network device obtains frequency deviation, wherein the frequency deviation is the deviation between the system frequency of the first network device and the system frequency of a second network device, and the second network device is upstream time synchronization equipment of the first network device;

the first network equipment obtains time deviation according to the frequency deviation, wherein the time deviation is generated by the frequency deviation of the first network equipment and the second network equipment;

and the first network equipment adjusts the system time according to the time deviation.

2. The method of claim 1, wherein the first network device obtaining a time offset from the frequency offset comprises:

the first network equipment obtains time deviation according to the frequency deviation and a first period, wherein the time deviation is generated by the first network equipment and the second network equipment in the first period, and the first period is a period of system time adjusted by the first network equipment according to the time deviation.

3. The method of claim 2, wherein the first period is less than a second period, the second period being a period during which the first network device adjusts the system time according to a filtering algorithm, the filtering algorithm being a proportional-differential integral control algorithm.

4. A method according to any of claims 1 to 3, wherein the first network device obtaining a frequency deviation comprises:

the first network device obtains N time delay data, wherein the N time delay data are used for indicating message transmission time delay between the first network device and the second network device, and N is a positive integer greater than or equal to 2;

and the first network equipment obtains the frequency deviation according to the N delay data.

5. The method of claim 4, wherein the N delay data comprises first delay data and second delay data, and wherein obtaining the N delay data comprises:

the first network equipment obtains the first delay data according to the first message transmission delay;

the first network device obtains the second time delay data according to the second message transmission time delay and the adjustment value of the system time in the specific time length, wherein the adjustment value of the system time in the specific time length is the adjustment value of the system time between the time corresponding to the first time delay data and the time corresponding to the second time delay data.

6. The method of claim 5, wherein the adjustment value of the system time comprises adjusting the adjustment value of the system time according to a filtering algorithm.

7. The method according to claim 5 or 6, wherein the adjustment value of the system time comprises the adjustment value of the system time according to the time offset.

8. The method of claim 4, wherein any one of the N latency data is a packet transmission latency between the first network device and the second network device.

9. The method according to any one of claims 4 to 8, wherein the first network device obtaining the frequency deviation from the N delay data comprises:

and the first network equipment processes the N time delay data according to a least square method to obtain the frequency deviation and the error, wherein the error is smaller than or equal to a first threshold value.

10. The method according to any one of claims 4 to 9, wherein the first network device obtaining the frequency deviation from the N delay data comprises:

and in a third period, the first network device obtains the frequency deviation according to the N pieces of delay data, wherein the third period is the obtaining period of the frequency deviation.

11. The method according to any one of claims 4 to 10, wherein N is less than or equal to a second threshold value, the second threshold value being greater than or equal to 3.

12. The method according to any of claims 1 to 11, wherein the first network device is a network device that does not support frequency adjustment.

13. The method according to any of claims 1 to 11, wherein the first network device is a network device supporting frequency adjustment.

14. The method of claim 13, wherein the method further comprises:

and if the frequency deviation is greater than or equal to a third threshold value, the first network equipment switches the frequency source to the second network equipment.

15. A network device, comprising:

an obtaining unit, configured to obtain a frequency deviation, where the frequency deviation is a deviation between a system frequency of the first network device and a system frequency of a second network device, and the second network device is an upstream time synchronization device of the first network device;

the obtaining unit is further configured to obtain a time offset according to the frequency offset, where the time offset is a time offset generated by the frequency offset by the first network device and the second network device;

and the adjusting unit is used for adjusting the system time according to the time deviation.

16. The network device according to claim 15, wherein the obtaining unit is specifically configured to:

and obtaining time deviation according to the frequency deviation and a first period, wherein the time deviation is generated by the first network equipment and the second network equipment in the first period, and the first period is a period of the system time adjusted by the adjusting unit according to the time deviation.

17. The network device of claim 16, wherein the first period is less than a second period, the second period being a period during which the adjustment unit adjusts the system time according to a filtering algorithm, the filtering algorithm being a proportional-differential integral control algorithm.

18. The network device according to any of the claims 15 to 17, characterized in that the obtaining unit is specifically configured to:

obtaining N time delay data, wherein the N time delay data are used for indicating the message transmission time delay between the first network equipment and the second network equipment, and N is a positive integer greater than or equal to 2;

and obtaining the frequency deviation according to the N time delay data.

19. The network device according to claim 18, wherein the obtaining unit is specifically configured to:

Acquiring the first delay data according to the first message transmission delay;

and acquiring the second time delay data according to the second message transmission time delay and the adjustment value of the system time in the specific time length, wherein the adjustment value of the system time in the specific time length is the adjustment value of the system time between the time corresponding to the first time delay data and the time corresponding to the second time delay data.

20. The network device of claim 19, wherein the adjustment value of the system time comprises an adjustment value that adjusts the system time according to a filtering algorithm.

21. The network device according to claim 19 or 20, wherein the adjustment value of the system time comprises the adjustment value of the system time according to the time offset.

22. The network device of claim 18, wherein any one of the N latency data is a message transmission latency between the first network device and the second network device.

23. The network device according to any of the claims 18 to 22, wherein the obtaining unit is specifically configured to:

and processing the N time delay data according to a least square method to obtain the frequency deviation and the error, wherein the error is smaller than or equal to a first threshold value.

24. The network device according to any of the claims 18 to 23, characterized in that the obtaining unit is specifically configured to:

and in a third period, the frequency deviation is obtained according to the N time delay data, and the third period is the obtaining period of the frequency deviation.

25. The network device of any one of claims 18 to 24, wherein the N is less than or equal to a second threshold, the second threshold being greater than or equal to 3.

26. The network device according to any one of claims 15 to 25, wherein the first network device is a network device that does not support frequency adjustment.

27. The network device according to any one of claims 15 to 25, wherein the first network device is a network device supporting frequency adjustment.

28. The network device of claim 27, wherein the network device further comprises:

and the switching unit is used for switching the frequency source to the second network equipment if the frequency deviation is larger than or equal to a third threshold value.

29. A network device, comprising:

a memory having computer readable instructions stored therein;

A processor coupled to the memory, the computer readable instructions, when executed by the processor, cause the network device to implement the method of any one of claims 1 to 14.

30. A computer program product comprising computer readable instructions which, when run on a computer, implement the method of any one of claims 1 to 14.

31. A computer readable storage medium having instructions stored therein which, when executed on a processor, implement the method of any one of claims 1 to 14.

32. A communication system comprising a first network device for performing the method of any of claims 1 to 14.