CN116566529A - Time adjustment method, network equipment and system - Google Patents

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

A time adjustment method, network equipment and system

technical field

The present application relates to the technical field of communications, and in particular to a time adjustment method, network equipment and system.

Background technique

In-situ flow information telemetry (IFIT) is a detection technology that directly detects performance indicators such as time delay, packet loss, and jitter of the network by marking the real service flow of the network. The IFIT delay measurement function requires high time synchronization performance between devices.

The precision time protocol (precision time protocol, PTP) specifies the time adjustment method between communication devices. Specifically, the devices send PTP messages and use the filtering algorithm to periodically adjust the time to realize the system time of the network device and the upstream time. Synchronize the system time of the device.

However, since the higher the modulation frequency of filter adjustment, the worse the noise filtering ability of the communication equipment, and, limited by the time adjustment loop bandwidth, the time deviation of each adjustment is limited, the system time of the communication equipment is compared with the system time of the upstream time synchronization equipment. The time deviation of the time will fluctuate with time, such as presenting a sawtooth wave. The amplitude peak of the sawtooth wave is high, and the time synchronization performance is poor, which cannot meet the high requirements for time synchronization performance such as IFIT technology.

Contents of the invention

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

In a first aspect, the present application provides a time adjustment method, including: a first network device obtains 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 The second network device is an upstream time synchronization device of the first network device; the first network device obtains a time offset according to the frequency offset, and the time offset is the first network device and the second network A device time deviation generated by the frequency deviation; the first network device adjusts system time according to the time deviation.

Based on the solution provided by this application, since the frequencies of the first network device and the upstream time synchronization device are not synchronized, a frequency deviation will occur, and then time deviations will continue to occur. The first network device obtains the first network device and the upstream time synchronization device. Calculate the time deviation caused by the frequency deviation and adjust the system time according to the frequency deviation, which can reduce the time deviation caused by the frequency deviation and improve the time synchronization performance.

In a possible implementation manner of the first aspect, the obtaining the time offset by the first network device according to the frequency offset includes: obtaining the time offset by the first network device according to the frequency offset and a first cycle, the The time offset is a time offset generated by the frequency offset between the first network device and the second network device within the first period, and the first period is the adjustment of the system time according to the time offset cycle.

The solution provided by the present application periodically adjusts the time deviation generated based on the frequency deviation based on the first period, so as to improve the time synchronization performance of the first network device.

In a possible implementation manner of the first aspect, the first period is shorter 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, and the filtering algorithm It is a proportional-differential-integral control algorithm.

In the solution provided by this application, the first period of adjusting the time deviation based on the frequency deviation is shorter than the second period adjusted based on the filtering algorithm. Therefore, the amplitude value of the time deviation sawtooth wave can be reduced, and the overall time synchronization performance can be improved.

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

In a possible implementation manner of the first aspect, the first network device receives the frequency offset 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 device according to The first packet transmission delay obtains the first delay data; the first network device obtains the second delay data according to the second packet transmission delay and the adjustment value of the system time within a specific duration, and the The adjustment value of the system time within the specific time period 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.

In the solution provided by this application, if there is a time adjustment in the specific duration corresponding to the N delay data, the delay needs to be compensated to obtain the delay data. Through compensation, the delay data in the delay array can be unified to the same reference time It is used to calculate frequency deviation, which improves the accuracy of frequency deviation calculation.

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

In a possible implementation 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 certain period of time, then adjusts the adjustment value of the system time according to the filtering algorithm and according to All the adjustment values of the time offset adjustment system time need to be used to compensate time delay so as to obtain 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 delay data in the N delay data, then the N delay data are all between the first network device and the second network device Packet transmission delay, it should be noted that the N pieces of delay data are obtained based on different time synchronization packets.

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

In the solution provided by this application, the first network device can linearly fit the delay data when estimating the frequency deviation. There are many linear fitting methods, such as the least square method, average value linear fitting, etc. Do limited. When the error corresponding to the frequency deviation satisfies 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.

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

The solution provided by this application can adjust the system time according to the calculated frequency deviation in the third period, recalculate the frequency deviation after the third period, and update the frequency deviation to further improve the time synchronization performance .

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

In the solution provided by the present application, the greater the amount of delay data used to calculate the frequency deviation, the higher the calculation accuracy and the more complex the calculation. The quantity of time-delay data is limited to be less than or equal to the second threshold, and the calculation complexity and accuracy of the frequency deviation can be controlled by setting the second threshold, and the calculation amount is controlled within a reasonable range while ensuring the calculation accuracy.

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

The solution provided by this application can be applied to network devices that do not support frequency adjustment to reduce time deviation.

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

The solution provided in this application can also be applied to network equipment supporting frequency adjustment to reduce time deviation.

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

In the solution provided by this application, if the first network device has a frequency adjustment loop in the hardware structure, it can perform frequency source switching when certain conditions are met (for example, the frequency deviation is greater than the third threshold), and by correcting the different sources of time and frequency, fundamentally It can significantly improve the time synchronization performance of network devices by avoiding time out of synchronization.

In a second aspect, the present application provides a network device, including: an obtaining unit, configured to obtain a frequency deviation, the frequency deviation being the deviation between the system frequency of the first network device and the system frequency of the second network device, so 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 deviation according to the frequency deviation, and the time deviation is the first network device and the first network device 2. A time deviation generated by the frequency deviation of the network equipment; an adjustment unit, configured to adjust the system time according to the time deviation.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: obtain a time offset according to the frequency offset and the first cycle, and the time offset is the first network device and the second network device. A time deviation of the network device generated by the frequency deviation within the first period, where the first period is a period for the adjustment unit to adjust the system time according to the time deviation.

In a possible implementation manner of the second aspect, the first period is shorter 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: obtain N delay data, and the N delay data are all used to indicate that the first network device and the second network device Packet transmission time delay between two network devices, the N is a positive integer greater than or equal to 2; the frequency deviation is obtained according to the N time delay data.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: obtain the first delay data according to the first packet transmission delay; The adjustment value of the system time obtains the second delay data, and the adjustment value of the system time within the specific duration is the system time between the time corresponding to the first delay data and the time corresponding to the second delay data. The adjustment value for the time.

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

In a possible implementation manner of the second aspect, any delay data in the N pieces of delay data is a packet transmission delay 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: process the N time delay data according to the least square method to obtain the frequency deviation and error, and the error is less than or equal to the first threshold.

In a possible implementation manner of the second aspect, the obtaining unit is specifically configured to: obtain the frequency deviation according to the N delay data in a third cycle, the third cycle being the frequency The acquisition period of the deviation.

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

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 that supports frequency adjustment.

In a possible implementation manner of the second aspect, the network device further includes: a switching unit configured to switch the frequency source to the second network device if the frequency deviation is greater than or equal to a third threshold.

In a third aspect, the present application provides a network device, which is characterized by comprising: one or more processors and a memory; wherein, computer-readable instructions are stored in the memory; the one or more processors read Acquiring the computer-readable instructions to enable the network device to execute the method described in any one of the above-mentioned first aspect and various possible implementation manners.

In a fourth aspect, the present application provides a computer program product containing instructions, which is characterized in that, when it is run on a computer, the computer executes any one of the above-mentioned first aspect and various possible implementations. the method described.

In a fifth aspect, the present application provides a computer-readable storage medium, including instructions, which is characterized in that, when the instructions are run on a computer, the computer is made to execute any of the above-mentioned first aspect and various possible implementation manners. one of the methods described.

In a sixth aspect, the present application provides a chip, including a processor. The processor is used to read and execute the computer program stored in the memory, so as to execute the method in any possible implementation manner of any aspect above. Optionally, the chip includes a memory, and the memory and the processor are connected to the memory through a circuit or wires. Further optionally, the chip further includes a communication interface, and the processor is connected to the communication interface. The communication interface is used to receive data and/or information to be processed, and the processor obtains the data and/or information from the communication interface, processes the data and/or information, and outputs the processing result through the communication interface. The communication interface may be an input-output interface.

Wherein, the technical effect brought by the second aspect, the third aspect, the fourth aspect, the fifth aspect or the sixth aspect and any one of the implementation methods can refer to the technical effect brought by the corresponding implementation method in the first aspect, I won't repeat them here.

In the time adjustment method provided by the present application, the first network device obtains the time deviation through the frequency deviation and adjusts the system time, which can reduce the time deviation caused by the frequency deviation and improve time synchronization performance. Taking the CPE communication equipment CPE equipment without hardware adjustment loop as an example, the TE performance is improved by more than 5 times.

For devices that support frequency adjustment loops and time adjustment loops on the hardware of the core layer, aggregation layer, or access layer in the communication network, it can effectively detect whether the frequency and time are different sources, and improve the IFIT time of the frequency and time different source scenarios synchronization performance. Since the time adjustment method provided by this application has no requirements on the time source or frequency source of network devices, it is not necessary to check the clock tracking paths of thousands of devices in the entire network, which reduces the difficulty of deployment and operation and maintenance of the IFIT time synchronization feature. It can support more application scenarios and improve operation and maintenance efficiency.

Description of drawings

FIG. 1 is an application scenario architecture diagram of the time adjustment method provided by the embodiment of the present application;

FIG. 2 is another application scenario architecture diagram of the time adjustment method provided by the embodiment of the present application;

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

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

Fig. 5 is the schematic diagram of time deviation sawtooth wave;

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

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

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

FIG. 9 is a schematic diagram of another embodiment of a network device in the embodiment of the present application.

Detailed ways

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

Embodiments of the present application are described below in conjunction with the accompanying drawings. Apparently, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Those of ordinary skill in the art know that, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

The terms "first", "second" and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or modules is not necessarily limited to the expressly listed Instead, other steps or modules not explicitly listed or inherent to the process, method, product or apparatus may be included. The naming or numbering of the steps in this application does not mean that the steps in the method flow must be executed in the time/logic sequence indicated by the naming or numbering. The execution order of the technical purpose is changed, as long as the same or similar technical effect can be achieved.

The application scenario architecture of the time adjustment method in the embodiment of the present application is introduced below. 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 application.

As shown in Figure 1, an application scenario of the time adjustment method provided by the embodiment of the present application includes network equipment NE-1 and network equipment NE-2. NE-1 and NE-2 can be connected directly or through other network equipment. . Among them, NE-1 is the upstream time synchronization device of NE-2, and the specific device type is not limited. NE-2 is a device that does not support frequency synchronization in hardware, such as agile transport network (ATN), packet transport network (PTN), customer premises equipment (CPE), etc. without phase detectors , equipment without direct digital synthesizer (direct digital synthesizer, DDS) and other devices. In the scenario shown in FIG. 1 , a time synchronization loop is included for time synchronization between NE-2 and NE-1.

As shown in Figure 2, another application scenario of the time adjustment method provided by the embodiment of the present application includes network equipment NE-1, network equipment NE-2, and network equipment NE-3. NE-3 and NE-1 can be directly connected. It can also be connected through other network devices. Similarly, NE-3 and NE-2 can be connected directly or through other network devices. NE-3 is a device that supports frequency synchronization on the hardware. Among them, NE-1 is the frequency tracking source of NE-3, and the system clock frequency of NE-3 is synchronized with the system clock frequency of NE-1. NE-2 is the upstream time synchronization device of NE-3. NE-3 synchronizes time with NE-2 by sending and receiving time synchronization packets.

In communication network equipment, frequency synchronization is the premise of time synchronization. The frequency synchronization performance of the system clock in the equipment affects the time synchronization performance. When the frequency is not synchronized, the time synchronization performance is poor. Refer to Figure 1 and Figure 2 for specific analysis below.

Based on the application scenario of different sources of time and frequency shown in FIG. 1 , the network device NE-2 performs time synchronization by sending and receiving time synchronization packets with the upstream time synchronization device NE-1. NE-1 marks a time stamp T1 at the time of sending the time synchronization message, and NE-2 marks a time stamp T2 at the time of receiving the time synchronization message. The time stamp T2 is based on the clock mark of the free oscillation of the local crystal oscillator of NE-2, and the time stamp T1 is based on the mark of the system clock of NE-1. If the system clock of NE-1 is not synchronized with the free oscillation clock of the local crystal oscillator of NE-2, the As a result, the accuracy of the time delay data calculated based on the time stamp T1 and time stamp T2 is reduced, and the time synchronization performance of NE-2 is poor.

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

1) The frequency source of NE-3 comes from the clock source communication building timing supply system (building integrated timing supply, BITS) (because the frequency source of NE-1 comes from the clock source BITS), but the time source of NE-3 comes from NE-2 , therefore, NE-3 has different sources of frequency and time.

2) The frequency source of NE-3 comes from NE-1 (the frequency source of NE-1 does not come from BITS), but the time source of NE-3 comes from the clock source BITS (because the time source of NE-2 comes from BITS) , therefore, NE-3 has different sources of frequency and time.

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

From the above situations, it can be seen that although the network device NE-3 has a time synchronization loop and a frequency synchronization loop, the frequency source has always existed, but the frequency source and the time source are different sources. In addition, the network device may also have a normal tracking frequency The source is lost and the device changes from active to passive.

The network device NE-3 performs time synchronization by sending and receiving time synchronization packets with the upstream time synchronization device NE-2. NE-2 marks a time stamp T1 at the time of sending the time synchronization message, and NE-3 marks a time stamp T2 at the time of receiving the time synchronization message. Time stamp T2 is based on the system clock mark of NE-1, and time stamp T1 is based on the system clock mark of NE-2. The system clock of NE-1 is not synchronized with the system clock of NE-2. The accuracy of the time delay data calculated by the time stamp T2 decreases, and the time synchronization performance of NE-3 is poor.

In some specific business scenarios, the time synchronization performance of network devices is highly required, such as in-situ flow information telemetry (IFIT) delay measurement scenarios. IFIT is to characterize real network traffic, A detection technology that directly detects network performance indicators such as delay, packet loss, and jitter. The higher the time synchronization accuracy of network devices, the more accurate IFIT delay measurement will be.

Please refer to Figure 3 to briefly introduce the principle of IFIT delay measurement. On the ingress (ingress) side, NE1 performs delay coloring on one of the packets of the detected service flow in this period according to the measurement cycle, and records the ingress timestamp T1 of the packet. , T3, and report to the centralized computing unit, the egress end, according to the same cycle of the ingress end, records the egress timestamps T2, T4 of the detected service flow delay dyeing messages in each cycle, and reports to the centralized computing unit. The centralized calculation unit calculates the one-way delay of the service flow in the two directions of cycle i according to the information reported by the ingress end and the egress end. The one-way delay from NE1 to NE2 is T2-T1, and the one-way delay from NE2 to NE1 is T4-T3, when the two-way path of the detected service flow is the same, the two-way time delay of the service flow period i can be calculated, which is (T2-T1)+(T4-T3), and the calculation method of the time delay in the embodiment of the present application is not Do limited.

In order to ensure the synchronization of the dyeing cycle at the ingress (ingress) end and the egress (egress) end, a time synchronization mechanism needs to be deployed. The existing time synchronization mechanism is usually based on the precision time protocol (precision time protocol, PTP) protocol, and the time is adjusted through a filtering algorithm. . It should be noted that the time adjustment method provided by the embodiment of the present application does not limit the time synchronization protocol that the network device complies with. Time synchronization packets can be sent based on the PTP protocol to obtain the time stamp, or it can be obtained based on other time synchronization protocols. Stamp information, such as NTP protocol. The filter adjustment is based on the proportion integral differential (PID) control principle, according to the required bandwidth, using the phase-locked loop to perform filter processing to achieve time synchronization and time adjustment, which can remove the service noise of the network equipment. Since the higher the modulation frequency of filter adjustment, the worse the noise filtering ability of the communication equipment, and the time deviation of each adjustment is limited, the time deviation between the system time of the communication equipment and the system time of the upstream time synchronization equipment will fluctuate with time, for example, The sawtooth wave has a high peak amplitude and poor time synchronization performance, which cannot meet the high requirements for time synchronization performance such as IFIT technology.

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

Referring to FIG. 4 , an embodiment of the present application proposes a time adjustment method 400 for improving time synchronization performance. The method 400 can be applied to the scenario shown in FIG. 1 or FIG. 2, wherein, in the application scenario shown in FIG. 1, the first network device is equivalent to NE-2 shown in FIG. 1, and the second network device is equivalent to NE-1 shown in Figure 1; in the application scenario shown in Figure 2, the first network device is equivalent to NE-3 shown in Figure 1, and the second network device is equivalent to NE-2 shown in Figure 1, 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 complying with the PTP protocol, the system time may be adjusted through a filtering algorithm (hereinafter referred to as filter adjustment).

S401. The first network device obtains a frequency deviation.

The frequency deviation is the deviation between the system frequency of the first network device and the system frequency of the second network device, and the second network device 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 methods:

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

Manner 2: The first network device obtains the frequency deviation according to the N delay data. Specifically, it includes: the first network device obtains N time delay data, where N is a positive integer greater than or equal to 2, and the first network device obtains the frequency deviation according to the N time delay data.

The first network device may calculate time delay according to sending and receiving time synchronization packets between the first network device and the second network device, and obtain N time delay data according to the time delay.

It should be noted that the first network device can filter and adjust the system time. Specifically, the first network device can use the second-order phase-locked loop algorithm to adjust the system time according to the timestamps T1, T2, T3 and T4 of the PTP message. The time interval for filter adjustment is periodically adjusted. For example, the time interval for filter adjustment is 5 seconds. The time interval for filter adjustment can support configuration. The time interval for filter adjustment is related to the bandwidth of the phase-locked loop, and the specific value is not limited. Exemplarily, the NE-2 device performs filter adjustment every 5 seconds by using a second-order phase-locked loop algorithm according to the time stamps T1, T2, T3, and T4 of the PTP message.

As a specific implementation method, based on whether the system time is adjusted during the process of obtaining N time-delay data, there are many ways to obtain N time-delay data, including: method 1, any one of N time-delay data The delay data is a packet transmission delay between the first network device and the second network device. That is to say, the first network device does not perform time adjustment during the process of acquiring the N time-delay data, and each time-delay data is directly calculated from the time stamp information.

The first network device can calculate the delay according to the time synchronization message sent and received between the first network device and the second network device, that is, by stamping the time synchronization message at the sending time and receiving time, and periodically obtaining the time stamp information, according to Time stamp information acquisition delay. The first network device activates the IFIT time synchronization function, obtains time stamp information (T1, T2, T3, and T4) once, and obtains time delay according to the time stamp information. Exemplarily, after the IFIT time synchronization function of the NE-2 device is enabled, time stamp information is acquired once per second. It should be noted that there are many calculation methods for the time synchronization packet transmission delay between the first network device and the second network device, including any of the following types: T2-T1, or T4-T3, or [(T4 -T3)+(T2-T1)]/2, the specific calculation method is not limited here. In addition, the sending rate of the time synchronization message is not limited.

Mode 2, because in the process of calculating the delay, 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 this embodiment of the present application. Therefore, in order to calculate the frequency deviation, the original time delay needs to be compensated. The N delay data include first delay data and second delay data, the first network device obtains the first delay data according to the first message transmission delay; the first network device obtains the first delay data according to the second message transmission delay and The adjustment value of the system time within a specific time length obtains the second delay data, and the adjustment value of the system time within the specific time length is the system time between the time corresponding to the first delay data and the time corresponding to the second delay data adjustment value. Here, the first delay data is directly obtained according to the first message transmission delay, and the specific duration refers to the time period between the time corresponding to the first delay data and the time corresponding to the second delay data, because The system time has been adjusted, and the second time delay data needs to be compensated according to the adjustment value, so that the first time delay data and the second time delay data can be jointly used for deviation calculation. The N delay data used for frequency offset calculation can be regarded as the transmission delay at the same reference time, that is to say, the time adjustment made by the first network device to the system time in the time period corresponding to all the delay data is excluded Impact. If the time synchronization adjustment is performed after the time corresponding to the first delay and before the time corresponding to the second delay, the second delay data recorded in the delay array is the second delay after being adjusted and compensated according to the time delay. Further, if multiple time adjustments are performed between the time corresponding to the first delay and the time corresponding to the third delay, the third delay data recorded in the delay array is the third delay according to the multiple The time delay after accumulating and compensating for an adjustment value.

It should be noted that the adjustment value of the system time includes the adjustment value of the system time according to the filtering algorithm, or the adjustment value of the system time according to the time deviation, or both the adjustment value of the system time according to the filtering algorithm and the adjustment value of the system time according to the The time offset adjusts the adjustment value of the system time.

Exemplarily, the time offset adjustment value every 5 seconds is accumulated and compensated to the time delay to obtain the time delay data, for example, compensated to (T2-T1), that is, the time delay data calculated by the time stamp obtained each time (T2-T1) is added to the accumulated result of the time offset adjustment value to obtain the time delay data, and the time delay data is stored in an array for subsequent frequency deviation calculation.

The first network device obtains the frequency deviation according to the N time delay data, including: the first network device processes the N time delay data according to a least square method to obtain the frequency deviation and an error, and the error less than or equal to the first threshold. It should be noted that the first network device may calculate the frequency deviation through linear fitting based on the N delay data. There are many linear fitting methods, such as least squares method, mean linear fitting, etc., which are not specifically limited. For example, the first network device performs linear fitting on the N time delay data according to the least square method to obtain the frequency deviation. The first network device performs linear fitting on the delay array according to the least square method to obtain a frequency deviation and an error corresponding to the frequency deviation, where the error is less than or equal to a first threshold. The first threshold can be configured according to specific requirements, such as the principle of three sigma (3sigma, 3σ), and the specific value is not limited here. When the error is less than or equal to the first threshold, it is determined that the frequency offset is valid; if the error is greater than the first threshold, the frequency offset is invalid, and the time delay data needs to be reacquired before calculation.

In a specific implementation, the N time-delay data can be the time-delay data after data screening, such as deleting the time-delay data with significant errors, etc., which can be realized by various existing methods, and will not be repeated here. repeat.

Obtaining the frequency offset by the first network device according to the N delay data includes: within a third cycle, the first network device obtains the frequency offset according to the N delay data, and the third cycle is a period of the frequency offset Get cycle. The third period may be, for example, 30 seconds, or 1 minute, and the specific numerical value is not limited. It should be noted that, when the third period is exceeded, the first network device may regain the frequency offset and use it for subsequent calculation of the time offset.

It can be understood that the amount of delay data is related to the accuracy of frequency offset estimation, computational complexity and real-time performance, and can support configuration. The N is less than or equal to a second threshold, and the second threshold is greater than or equal to three. Exemplarily, the delay data is recorded through the 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 device obtains the time offset according to the frequency offset.

According to the frequency deviation, the first network device can calculate the time deviation caused by the frequency deviation of the first network device within a period of time. Optionally, the first network device obtains a time deviation according to the frequency deviation and the first period, and the time deviation is obtained by the frequency deviation between the first network device and the second network device within the first period resulting time deviation. The first period is a period in which the first network device adjusts the system time according to the time offset.

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

In a specific implementation manner, the first period is shorter than the second period, and the second period is a period for the first network device to adjust the system time according to a filtering algorithm, where the filtering algorithm is a proportional differential integral control algorithm. Exemplarily, the first period is 1 second, and the second period is 5 seconds. Optionally, the first period is greater than or equal to the time interval for obtaining the time stamp, and is less than the second period. Optionally, the specific value of the first cycle supports configuration, and is related to the timer supported by the hardware of the first network device, and the timer includes a 1s timer or a 100ms timer.

S403. The first network device 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 the time point for modulating the system time according to the first period, and adjusts the system time at this time point, for example, the first period is 5 seconds .

Exemplarily, the time deviation introduced by the frequency deviation is adjusted quickly, for example, the adjustment interval is 1 second, and the adjustment value of the time deviation is sent to the real-time clock (RTC) every second to realize the adjustment of the system time of the first network device, In addition, this time offset is counter-compensated into the delay data by accumulating.

In a specific implementation, if the time point is still the time point corresponding to the filter adjustment (can be determined according to the second cycle), then at this time point, the time adjustment is performed according to the filter adjustment, and the time adjustment is performed according to the time deviation or according to the time The deviation and filter adjustment time difference are used for time adjustment, which is not limited here.

Further, if the first network device is a network device supporting frequency adjustment as shown in FIG. 2 , the method further includes: if the frequency deviation is greater than or equal to a third threshold, the first network device switches the frequency source to the second network device. The value of the third threshold can be set according to the use requirements and supports configuration. Its value can be related to the maximum frequency deviation range normally supported by the application scenario business. When the frequency deviation exceeds the third threshold, it may cause business abnormalities. The specific value of the third threshold is here There is no limit. Optionally, frequency switching can be combined with the clock network topology and performed on the premise of obtaining customer requirements. For example, the frequency source of NE-3 is switched from NE-1 to NE-2, that is, the frequency source is switched to the same path as the PTP message, so that the frequency and time have the same source, and finally improve the performance of IFIT time synchronization, completely Eliminate the sawtooth wave of TE, not just reduce the amplitude value of the sawtooth wave. The time adjustment method provided in the embodiment of the present application obtains the time deviation through the frequency deviation and adjusts the system time, which can reduce the time deviation caused by the frequency deviation and improve time synchronization performance.

Furthermore, due to the existence of frequency offset, the time offset caused by frequency offset between two consecutive filter adjustments will increase linearly. Referring to Figure 5, the sawtooth wave amplitude is high, and the time synchronization performance is poor, which cannot meet the requirements of IFIT technology in delay measurement. High requirements on time synchronization accuracy. However, in the time adjustment method provided by the embodiment of the present application, if the first period is less than the second period, that is, the first network device adjusts the time deviation caused by the frequency deviation by adjusting a higher frequency than filtering, which can reduce the amplitude of the sawtooth wave value, improve the time synchronization performance of the first network device, and meet the high requirements for time synchronization accuracy in delay measurement of IFIT technology. The change of the time offset in the time adjustment method provided by the present application will be introduced below with reference to FIG. 6 and FIG. 7 .

The black solid line 601 in the figure represents the time difference between the first network device and the second network device over time, and the gray solid line represents the adjustment of the system time by the first network device, including filter adjustment 6021 and time adjustment according to the time deviation. Adjustment (in this embodiment, the first period of time adjustment according to the time deviation is shorter than the second period of filter adjustment, for the convenience of description, it is called quick adjustment) 6022. It can be seen that when adjusting the time, the first network device The time deviation between the first network device and the second network device is reduced, and the time difference between the first network device and the second network device presents a sawtooth waveform as a whole. After the IFIT time synchronization function of the first network device is enabled, the time stamp information can be obtained and the delay between the first network device and the second network device can be calculated. The five-pointed star 603 in FIG. 6 represents the time delay data with noise, and the time The delayed data is time compensated, including filter adjustment based time compensation 6041 and fast adjustment based time compensation 6042 . Due to the noise in the time delay data, the frequency deviation is calculated by linear fitting technique. In the time adjustment method provided by the embodiment of the present application, the network device quickly adjusts the time to reduce the amplitude value of the sawtooth wave. As shown in the figure, point A is reduced to point B, and the time synchronization accuracy is improved, which can better meet technologies such as IFIT High demands on time synchronization. In the time adjustment method provided in the embodiment of the present application, the time interval for fast adjustment is shorter than the time interval for filter adjustment. In a possible implementation, the time interval for filter adjustment and the time interval for fast adjustment are not integer multiples. For example, referring to FIG. 7 , at the time of the quick adjustment (for example, t1), the first network device performs the quick adjustment according to the time offset of the quick adjustment. At the time of filter adjustment (for example, t2), the first network device performs filter adjustment to implement time synchronization. It can be understood that the filter adjustment and the fast adjustment are performed independently of each other without affecting each other, wherein the filter adjustment can remove service noise of the network device, and the fast adjustment is used to remove the noise caused by the frequency deviation. Correspondingly, the time adjustment is supplemented in the time delay array, including time compensation based on fast adjustment and time compensation based on filter adjustment. After the rapid adjustment in the time adjustment method of the embodiment of the present application, it can be seen that the amplitude value of the time deviation sawtooth wave is reduced from point A to point B, and the time synchronization accuracy is improved, which can better meet the high requirements of IFIT and other technologies for time synchronization .

The time adjustment method provided by the present application is introduced above, and the network device implementing the time adjustment method is introduced below. Please refer to FIG. 8 , which is a schematic diagram of an embodiment of the network device in the embodiment of the present application.

The network equipment, including:

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

Optionally, the obtaining unit 801 is specifically configured to: obtain a time offset according to the frequency offset and the first period, the time offset is the first network device and the second network device in the first period A time deviation generated by the frequency deviation, the first period is a period in which the adjustment unit adjusts the system time according to the time deviation.

Optionally, the first period is shorter than a second period, and 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.

Optionally, the obtaining unit 801 is specifically configured to: obtain N delay data, and the N delay data are all used to indicate the packet between the first network device and the second network device Transmission delay, where N is a positive integer greater than or equal to 2; the frequency deviation is obtained according to the N delay data.

Optionally, the obtaining unit 801 is specifically configured to: obtain the first delay data according to the first packet transmission delay; obtain the second packet transmission delay and an adjustment value of the system time within a specific duration. For the second delay data, the adjustment value of the system time within the specific duration 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.

Optionally, the adjustment value of the system time includes adjusting the adjustment value of the system time according to a filtering algorithm.

Optionally, the adjustment value of the system time includes the adjustment value of adjusting 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.

Optionally, the obtaining unit 801 is specifically configured to: process the N time delay data according to a least square method to obtain the frequency deviation and error, where the error is less than or equal to a first threshold.

Optionally, the obtaining unit 801 is specifically configured to: obtain the frequency offset according to the N time delay data in a third period, where the third period is an acquisition period of the frequency offset.

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

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: 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 introduced in the foregoing embodiments, and the specific implementation process and beneficial effects will not be repeated here. It should be understood that the above division of each unit of the network is only a division of logical functions, and may be fully or partially integrated into one physical entity or physically separated during actual implementation. And these units can be implemented in the form of software calling through the processing element; all can be implemented in the form of hardware; some units can also be implemented in the form of software calling through the processing element, and some units can be implemented in the form of hardware.

For example, the above units may be one or more integrated circuits configured to implement the above method, for example: 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), etc. For another example, when one of the above units is implemented in the form of a processing element scheduler, the processing element may be a general processor, such as a central processing unit (central processing unit, CPU) or other processors that can call programs. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

Please refer to FIG. 9 , which is a schematic diagram of another embodiment of the network device in the embodiment of the present application.

The network device provided in this embodiment may be an ATN, a PTN or a CPE, or a network device at a core layer, a convergence layer, or an access layer in a communication network. The embodiment of the present application does not limit the specific device form.

The network device 900 may have relatively large differences due to different configurations or performances, and may include one or more processors 901 and memory 902, and the memory 902 stores programs or data.

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

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

Optionally, although not shown in FIG. 9 , the network device 900 can also include one or more power supplies; one or more input and output interfaces, which can be used to connect a display, mouse, keyboard, touch screen device or sensor Equipment, etc., input and output interfaces are optional components, which may or may not exist, and are not limited here.

For the process executed by the processor 901 in the network device 900 in this embodiment, reference may be made to the method process described in the foregoing method embodiments, and details are not repeated here. Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can 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 into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

If the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (read-only memory, ROM), random access memory (random access memory, RAM), magnetic disk or optical disk and other various media that can store program codes. .

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the application.

Claims (32)

1. A time adjustment method, characterized in that, comprising: The first network device obtains a frequency offset, where the frequency offset 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 of the first network device equipment; The first network device obtains a time offset according to the frequency offset, where the time offset is a time offset generated by the frequency offset between the first network device and the second network device; The first network device adjusts system time according to the time offset. 2. The method according to claim 1, wherein the obtaining the time offset by the first network device according to the frequency offset comprises: The first network device obtains a time deviation according to the frequency deviation and a first period, and the time deviation is generated by the frequency deviation within the first period between the first network device and the second network device time deviation, the first period is a period for the first network device to adjust the system time according to the time deviation. 3. The method according to claim 2, wherein the first period is shorter than a 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 The filtering algorithm is proportional differential integral control algorithm. 4. The method according to any one of claims 1 to 3, wherein obtaining the frequency offset by the first network device comprises: The first network device obtains N delay data, and the N delay data are all used to indicate a packet transmission delay between the first network device and the second network device, and the N is A positive integer greater than or equal to 2; The first network device obtains the frequency offset according to the N delay data. 5. The method according to claim 4, wherein the N time-delay data comprises first time-delay data and second time-delay data, and the obtaining N time-delay data comprises: The first network device obtains the first delay data according to the first packet transmission delay; The first network device obtains the second delay data according to the second packet transmission delay and the adjustment value of the system time within a specific time length, and the adjustment value of the system time within the specific time length is the first delay data An adjustment value of the system time between the corresponding time and the time corresponding to the second delay data. 6. The method according to claim 5, wherein the adjustment value of the system time comprises an adjustment value of adjusting 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 adjusting the system time according to the time deviation. 8. The method according to claim 4, wherein any one of the N delay data is the packet transmission time between the first network device and the second network device delay. 9. The method according to any one of claims 4 to 8, wherein the first network device obtains the frequency deviation according to the N delay data, comprising: The first network device processes the N delay data according to a least square method to obtain the frequency deviation and error, where the error is less than or equal to a first threshold. 10. The method according to any one of claims 4 to 9, wherein the first network device obtaining the frequency deviation according to the N delay data comprises: In a third period, the first network device obtains the frequency offset according to the N delay data, and the third period is an acquisition period of the frequency offset. 11. The method according to any one of claims 4-10, wherein the N is less than or equal to a second threshold, and the second threshold is greater than or equal to three. 12. The method according to any one 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 one of claims 1 to 11, wherein the first network device is a network device supporting frequency adjustment. 14. The method of claim 13, further comprising: If the frequency deviation is greater than or equal to a third threshold, the first network device switches the frequency source to the second network device. 15. A network device, comprising: An obtaining unit, configured to obtain a frequency deviation, the frequency deviation being the deviation between the system frequency of the first network device and the system frequency of a second network device, the second network device being the upstream time of the first network device sync 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 between the first network device and the second network device; An adjustment unit, configured to adjust the system time according to the time deviation. 16. The network device according to claim 15, wherein the obtaining unit is specifically configured to: Obtaining a time offset according to the frequency offset and a first cycle, where the time offset is a time offset generated by the frequency offset between the first network device and the second network device within the first cycle, the The first period is a period during which the adjustment unit adjusts the system time according to the time deviation. 17. The network device according to claim 16, wherein the first period is shorter than a second period, and the second period is a period in which the adjustment unit adjusts the system time according to a filtering algorithm, and the filtering The algorithm is proportional differential integral control algorithm. 18. The network device according to any one of claims 15 to 17, wherein the obtaining unit is specifically configured to: Obtaining N delay data, the N delay data are all used to indicate the message transmission delay between the first network device and the second network device, and the N is a positive value greater than or equal to 2 integer; The frequency deviation is obtained according to the N time delay data. 19. The network device according to claim 18, wherein the obtaining unit is specifically configured to: Obtain the first delay data according to the first packet transmission delay; Obtain the second delay data according to the second packet transmission delay and the adjustment value of the system time within a specific time period, and the adjustment value of the system time within the specific time period is the same as the time corresponding to the first delay data The adjustment value of the system time between the times corresponding to the second delay data. 20. The network device according to claim 19, wherein the adjustment value of the system time comprises an adjustment value for adjusting 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 adjusting the system time according to the time deviation. 22. The network device according to claim 18, wherein any one of the N delay data is a message transmission between the first network device and the second network device delay. 23. The network device according to any one of claims 18 to 22, wherein the obtaining unit is specifically configured to: Processing the N time delay data according to a least square method to obtain the frequency deviation and error, where the error is less than or equal to a first threshold. 24. The network device according to any one of claims 18 to 23, wherein the obtaining unit is specifically configured to: In a third period, the frequency offset is obtained according to the N time delay data, and the third period is an acquisition period of the frequency offset. 25. The network device according to any one of claims 18-24, wherein the N is less than or equal to a second threshold, and the second threshold is greater than or equal to three. 26. The network device according to any one of claims 15-25, 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 15-25, wherein the first network device is a network device supporting frequency adjustment. 28. The network device according to claim 27, wherein the network device further comprises: A switching unit, configured to switch the frequency source to the second network device if the frequency deviation is greater than or equal to a third threshold. 29. A network device, comprising: a memory having computer readable instructions stored therein; A processor connected to the memory, when the computer-readable instructions are executed by the processor, the network device implements the method according to any one of claims 1-14. 30. A computer program product, characterized by comprising computer readable instructions, when the computer readable instructions are run on a computer, the method according to any one of claims 1 to 14 is realized. 31. A computer-readable storage medium, characterized in that instructions are stored in the computer-readable storage medium, and when the instructions are run on a processor, the computer-readable storage medium according to any one of claims 1 to 14 is implemented. Methods. 32. A communication system, comprising a first network device configured to perform the method according to any one of claims 1 to 14.