CN106301837B

CN106301837B - Passive optical network alarm detection method and device

Info

Publication number: CN106301837B
Application number: CN201510272606.5A
Authority: CN
Inventors: 郭敬文
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2015-05-25
Filing date: 2015-05-25
Publication date: 2020-02-14
Anticipated expiration: 2035-05-25
Also published as: WO2016188187A1; CN106301837A

Abstract

The invention provides a passive optical network alarm detection method and a device, wherein in the method, an optical line terminal OLT receives a power-off alarm reported by an optical network unit ONU, the difference value between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT is compared with a preset time slice threshold value, when the difference value reaches the preset time slice threshold value, the ONU is determined to meet the power-off alarm requirement, the number of the ONUs meeting the power-off alarm requirement under a passive optical network PON port to which the ONU belongs is counted, the number of the ONUs is compared with the total number of the ONUs under the PON port, and when the comparison result meets the preset requirement, the cell in which the PON is located is determined to be powered off, the problem of inconvenient processing of the alarm of the power-off of the ONUs is solved, and the convenience of an operator operation and maintenance management network is improved.

Description

Passive optical network alarm detection method and device

Technical Field

The invention relates to the field of communication, in particular to a passive optical network alarm detection method and a passive optical network alarm detection device.

Background

Passive Optical Network (PON, referred to as Passive Optical Network) technology is currently the first choice and mainstream technology in the field of Optical access networks, and has significant advantages in access rate, bandwidth efficiency, splitting ratio, full service carrying capacity, and security. PON technology is also classified into Ethernet Passive Optical Network (EPON) standardized by the IEEE802.3 First Mile Ethernet (EFM) working group of the Institute of Electrical and electronics Engineers (IEEE for Electrical and Electronic Engineers, IEEE for short) and Gigabit Passive Optical Network (GPON); the GPON technology is proposed and standardized by the international telecommunication Union-telecommunication standardization sector (ITU-T for short).

A typical PON system is composed of an Optical Line Terminal (OLT for short), a subscriber Optical Network Unit (ONU for short), and an Optical distribution Network (ODN for short), and The most common service scenarios are Fiber To The home (FTTH for short) and Fiber To The Building (FTTB for short). In an FTTH scene, each family is provided with an ONU (optical network unit) to provide services such as data, voice and the like for a single family; in the FTTB scenario, an ONU is deployed in a corridor and then connected to a user Home Network (HN) of a user through a cable. In the operation and maintenance management of a passive PON network, an operator usually has a special network monitoring center for monitoring the operation state of devices in the network in real time, and if the devices have alarms and reports, a work order is usually issued to arrange relevant maintenance engineers to eliminate obstacles. In the FTTB scenario, the ONU is deployed in a corridor and is not touched by a user. The ONU is typically powered off due to a failure of a device such as the power module of the ONU. In the FTTB scenario, once the ONU is powered off, the user service of the whole building is interrupted, which may lead to failure reporting and complaints of multiple users. Therefore, in an FTTB scenario, for the ONU power failure warning network, the network monitoring center focuses on the ONU power failure warning network, and once receiving such warning, the network monitoring center immediately issues a work order and arranges the relevant maintenance engineer for processing.

However, in actual operation and maintenance, a problem often occurs that a network monitoring center of an operator receives an alarm of power failure of a plurality of ONUs, and when maintenance engineers arrive at the site, such as when a work order is issued for arrangement and processing, the power failure of the ONUs is found to be caused by a power system failure and a power failure of the whole cell. Moreover, since a cell is often debugged due to the power system debugging, the cell is short in time, and therefore, the processing of a large number of alarms of ONU power failure caused by cell power failure in FTTB scenarios becomes a pain point in the operation and maintenance management process of an operator.

Aiming at the problem that the alarm processing of ONU power failure is inconvenient in the related technology, no effective solution is provided at present.

Disclosure of Invention

The invention provides a passive optical network alarm detection method and a passive optical network alarm detection device, which at least solve the problem of inconvenient processing of the alarm of ONU power failure in the related technology.

According to an aspect of the present invention, there is provided a passive optical network alarm detection method, including:

an optical fiber line terminal OLT receives a power failure alarm reported by an optical fiber network unit ONU;

comparing the difference value between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT with the preset time slice threshold value, and determining that the ONU meets the power-off alarm requirement under the condition that the difference value reaches the preset time slice threshold value;

counting the number of the ONUs meeting the power-off alarm requirement under the PON port of the passive optical network to which the ONUs belong, and comparing the number of the ONUs with the total number of the ONUs under the PON port;

and under the condition that the comparison result meets the preset requirement, determining that the cell where the PON is located is powered off.

Further, when the comparison result meets a preset requirement, determining that the power of the cell where the PON is located is off includes:

and under the condition that the number of the ONUs under the PON port, which meet the power-off alarm requirement, is equal to the total number of the ONUs under the PON port, determining that the cell where the PON is located is powered off.

Further, adding the power failure alarm reported by the ONU into the created queue, circularly detecting the difference value between the receiving time in the power failure alarm at the head of the queue and the generating time in the power failure alarm record, and removing the power failure alarm at the head of the queue under the condition that the difference value reaches the preset time slice threshold value.

Further, grouping the power-off alarms in the queue according to the PON port to which the ONU belongs;

and sequentially performing the cyclic detection according to the grouping.

Further, in case it is determined that the cell in which the PON is located is powered off, the method further includes at least one of:

discarding the reported power failure alarm;

and generating a cell power-off alarm indication of the PON, and sending the cell power-off alarm indication to a network control center.

According to another aspect of the present invention, there is also provided a passive optical network alarm detecting apparatus, including:

the receiving module is used for receiving the power failure alarm reported by the optical network unit ONU by the optical line terminal OLT;

the comparison module is used for comparing the difference value between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT with the preset time slice threshold value, and determining that the ONU meets the power-off alarm requirement under the condition that the difference value reaches the preset time slice threshold value;

the counting module is used for counting the number of the ONUs which meet the power-off warning requirement under the PON port of the passive optical network to which the ONUs belong and comparing the number of the ONUs with the total number of the ONUs under the PON port;

and the determining module is used for determining that the cell where the PON is located is powered off under the condition that the comparison result meets the preset requirement.

Further, the determining module includes:

a first determining unit, configured to determine that a cell where the PON is located is powered off when the number of ONUs under the PON port that meet the power-off alarm requirement is equal to a total number of ONUs under the PON port.

Further, the comparison module comprises:

and the first comparison unit is used for adding the power-off alarm reported by the ONU into the created queue, circularly detecting the difference value between the receiving time in the power-off alarm at the head part of the queue and the generating time in the power-off alarm record, and removing the power-off alarm at the head part of the queue under the condition that the difference value reaches the preset time slice threshold value.

Further, the apparatus further comprises:

the grouping module is used for grouping the power-off alarms in the queue according to the PON port to which the ONU belongs;

the first comparing unit is further configured to perform the cyclic detection in sequence according to the packets.

Further, the apparatus further comprises:

a discarding module, configured to discard the reported power failure alarm when it is determined that the cell in which the PON is located is powered off;

and the reporting module is used for generating a cell power-off alarm instruction of the PON and sending the cell power-off alarm instruction to a network control center under the condition that the cell where the PON is located is determined to be powered off.

According to the invention, an optical fiber line terminal OLT is adopted to receive the power-off alarm reported by an optical fiber network unit ONU, the difference value between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT is compared with the preset time slice threshold value, the ONU is determined to meet the power-off alarm requirement under the condition that the difference value reaches the preset time slice threshold value, the ONU number meeting the power-off alarm requirement under the PON port of the passive optical network to which the ONU belongs is counted, the ONU number is compared with the ONU total number under the PON port, and the ONU is determined to be powered off in the cell where the PON is located under the condition that the comparison result meets the preset requirement, so that the problem of inconvenient processing of the power-off alarm is solved, and the convenience of an operator operation and maintenance management network is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a flowchart of a passive optical network alarm detection method according to an embodiment of the present invention;

fig. 2 is a block diagram of a passive optical network alarm detection device according to an embodiment of the present invention;

fig. 3 is a flowchart of detecting a PON port cell power-off alarm in a passive optical network according to an embodiment of the present invention.

Detailed Description

The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

In this embodiment, a passive optical network alarm detection method is provided, and fig. 1 is a flowchart of a passive optical network alarm detection method according to an embodiment of the present invention, as shown in fig. 1, the flowchart includes the following steps:

step S12, the optical line terminal OLT receives the power-off alarm reported by the optical network unit ONU;

step S14, comparing the difference between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT with the preset time slice threshold, and determining that the ONU meets the power-off alarm requirement under the condition that the difference reaches the preset time slice threshold;

step S16, counting the ONU number meeting the power-off alarm requirement under the PON port of the passive optical network to which the ONU belongs, and comparing the ONU number with the ONU total number under the PON port;

step S18, determining that the cell where the PON is located is powered off when the comparison result meets the preset requirement.

Through the steps, the OLT receives the power-off alarm reported by the optical network unit ONU, determines whether the cell where the PON is located is powered off according to the power-off alarm generation time, the power-off alarm receiving time received by the OLT and the ONU number meeting the power-off alarm requirement under the PON port of the passive optical network to which the ONU belongs, issues a work order without receiving the power-off alarm, arranges a maintenance engineer to perform on-site processing, solves the problem of inconvenient processing of the ONU power-off alarm, and improves the convenience of the operation and maintenance management network of an operator.

In this embodiment, there may be a plurality of preset requirements, for example, when the comparison result indicates that the number of ONUs under the PON port that meet the power-off alarm requirement accounts for a majority of the total number of ONUs under the PON port, that is, the situation meets the preset requirement, it is determined that the cell where the PON is located is powered off; and determining that the cell where the PON is located is powered off under the condition that the number of the ONUs under the PON port, which meet the power-off alarm requirement, is equal to the total number of the ONUs under the PON port.

In this embodiment, the power failure alarm reported by the ONU may be added to a created queue, where the queue may be a first-in-first-out queue, a difference between a reception time in the power failure alarm at the head of the queue and a generation time in the power failure alarm record is cyclically detected, and the power failure alarm at the head of the queue is removed when the difference reaches the preset time slice threshold. And meanwhile, the power-off alarms in the queue can be grouped according to the PON port to which the ONU belongs, and the power-off alarms of the circulating detection queue are sequentially carried out according to the grouping.

In this embodiment, when it is determined that the cell in which the PON is located is powered off, the reported power-off alarm may be discarded, and a cell power-off alarm indication of the PON may also be generated and sent to the network control center.

In this embodiment, a passive optical network alarm detection apparatus is further provided, and the apparatus is used to implement the foregoing embodiments and preferred embodiments, and the description already made is omitted. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.

Fig. 2 is a block diagram of a passive optical network alarm detection device according to an embodiment of the present invention, and as shown in fig. 2, the device includes

The receiving module 22 is used for the optical fiber line terminal OLT to receive the power-off alarm reported by the optical fiber network unit ONU;

a comparing module 24, configured to compare a difference between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT with the preset time slice threshold, and determine that the ONU meets the power-off alarm requirement when the difference reaches the preset time slice threshold;

a counting module 26, configured to count the number of ONUs that meet the power-off warning requirement under a passive optical network PON port to which the ONU belongs, and compare the number of ONUs with the total number of ONUs under the PON port;

a determining module 28, configured to determine that the cell where the PON is located is powered off when a result of the comparison meets a preset requirement.

By the device, the OLT receives the power-off alarm reported by the optical network unit ONU, determines whether the cell where the PON is located is powered off according to the power-off alarm generation time, the power-off alarm receiving time received by the OLT and the ONU number meeting the power-off alarm requirement under the PON port of the passive optical network to which the ONU belongs, issues a work order without receiving the power-off alarm, arranges a maintenance engineer to perform on-site processing, solves the problem of inconvenient processing of the ONU power-off alarm, and improves the convenience of an operator operation and maintenance management network.

In this embodiment, the determining module 28 includes:

a first determining unit, configured to determine that the cell where the PON is located is powered off when the number of ONUs under the PON port that meet the power-off alarm requirement is equal to the total number of ONUs under the PON port.

In this embodiment, the comparing module 24 includes:

In this embodiment, the apparatus further comprises:

the grouping module is used for grouping the power-off alarm in the queue according to the PON port to which the ONU belongs;

the first comparing unit is further configured to perform the loop detection in sequence according to the packet.

In this embodiment, the apparatus further comprises:

and the reporting module is used for generating a cell power-off alarm instruction of the PON and sending the cell power-off alarm instruction to the network control center under the condition that the cell where the PON is located is determined to be powered off.

The present invention will be described in detail with reference to preferred examples and embodiments.

The preferred embodiment provides a Passive Optical Network (PON) system, which is applied to the management field of EPON or GPON network element devices (including an optical line terminal OLT and an optical network unit ONU). The method provides an alarm detection method for PON port service interruption caused by cell power failure in a passive optical network.

The preferred embodiment solves the problem that operators can judge the cause of the fault when the cell is powered off in the operation and maintenance process of the passive optical network system, and reports the PON port-level cell power-off alarm instead of reporting a large number of ONU power-off alarms when reporting the alarm to the network monitoring center, so that operation and maintenance personnel of the network monitoring center can recognize the cell power-off at a glance.

In the preferred embodiment, a set of methods for discovering the PON port cell power-off alarm is summarized according to the power-off alarms of different ONUs received under the same PON port by comparing the reporting time of the power-off alarms of the ONUs and according to the characteristics of the ONUs deployed by an operator.

Due to the networking characteristic of the passive optical network, the networking structure of the passive optical network is that an optical splitter is connected to a PON port, the optical splitter separates a main optical fiber into a plurality of branch optical fibers, and each branch optical fiber is accessed to an ONU. The number of branch optical fibers that can be separated from one trunk optical fiber is limited due to the intensity of optical signals. In actual use, 32 to 64 ONUs can be connected to one PON port, and the maximum case of the PON port does not exceed 256 ONUs. Therefore, in consideration of cost, the physical locations of ONUs under the same PON port are not too far away, and are usually in a cell. Even in a less densely populated cell, the operator reserves the branch optical fiber free under the PON port for capacity expansion rather than pulling the optical fiber far to other cells for use.

Another feature of the cell power-down alarm is that after a cell power-down occurs, the affected ONUs report power-down alarms simultaneously within a very short time, so that if an OLT network element receives power-down alarms of multiple ONUs under the same PON port within a very short actual time (experience data of 01. sec), it can basically be determined that a cell power failure occurs in a cell where the ONU connected under the PON port is located.

Based on the above two features, it can be determined whether a cell power-off alarm has occurred according to the information.

In this preferred embodiment, a method for detecting a PON port cell power-off alarm in a passive optical network is further provided, where the method includes the following steps:

step 1, an ONU in a network needs to support a power failure (Dying Gasp) alarm function, namely the ONU can report power failure alarm information to an OLT network element at the moment before power failure.

And 2, after receiving the alarm reported by the ONU, the OLT network element does not report the ONU power failure to the network management immediately but enters a local cache queue. Other alarms are immediately forwarded to the network manager.

And 3, comparing the occurrence time of the queue head alarm with the current detection time, and judging whether the time difference value reaches a set time slice value, if not, sleeping the set sleep time, and then detecting whether the difference value between the queue head and the current detection time reaches the set time slice value again. And circulating the steps until the time difference reaches or exceeds the set time delay time slice value.

And 4, marking the occurrence time of the current queue head alarm as T and the time slice value set in the step 3 as S. And sequentially removing the ONU power-off alarm records from the head of the queue and putting the ONU power-off alarm records into a processing queue until the alarm occurrence time at the head of the queue is later than T + S. And grouping all ONU power-off alarms in the processing queue according to the positions of the PON ports, wherein the ONU power-off alarms under the same PON port are placed in a set, and each set is identified by the position of the PON port.

Step 5, for each set generated in step 4, calculating the ONU number A of reporting ONU power-off alarm under the PON port, and then reporting the PON port cell power-off alarm according to the number B of the active ONUs under the PON port before the processing time slice stored in the system, wherein if A is equal to B, the PON port cell power-off alarm is reported, and the power-off alarm of each ONU is not reported any more; otherwise, reporting the power failure alarm of each ONU as before.

Wherein the step 1 can also be expanded to include the following steps:

the ONU reporting "Dying Gasp" alarm function in step 1 includes, but is not limited to, reporting power-off alarm information to the OLT immediately before the ONU powers off in a capacitive manner.

Wherein the step 2 can also be expanded to include the following steps:

the processing logic of step 5 also includes a special case, only the on-line ONU is present at the PON port, and in this case, because the probability of false alarm is too high, the processing of the algorithm is not used, but the ONU power-off alarm is continuously reported.

The preferred embodiment detects the cell power failure by the physical distribution characteristics of the ONUs at the PON port and the time sequence characteristics of power failure reported by each ONU at the PON port when the cell power failure occurs. The scheme has obvious innovation, and the prior art and the scheme do not have the same innovation as the technical scheme. The preferred embodiment solves the problem that other technologies cannot solve, and can find out the PON port cell power-off alarm which is difficult to detect by other technical means, thereby solving the pain of operators in the operation and maintenance process.

The invention also provides another embodiment, and the preferred embodiment is to detect the cell power-off by the physical location distribution characteristics of the ONUs under the PON port and the time sequence characteristics of power-off reported by each ONU under the PON port under the condition of cell power-off.

Fig. 3 is a flowchart of detecting a PON port cell power-off alarm in a passive optical network according to an embodiment of the present invention, and as shown in fig. 3, illustrates a process of detecting a PON port cell power-off alarm.

Step 101: monitoring an alarm reported by an ONU by an OLT network element;

and the OLT network element monitors the alarms reported by all the ONUs. The ONU needs to be guaranteed to have the capability of reporting the ONU power-off alarm, that is, at the moment before the ONU is powered off, the ONU can report the power-off alarm to the OLT network element by using a capacitor or other technologies.

Step 102: judging the type of the alarm after the OLT receives the alarm;

after receiving the alarm reported by the ONU, the OLT network element judges whether the alarm is the ONU power-off alarm or not, and if the alarm is the ordinary alarm without the ONU power-off, the OLT network element goes to step 110 for processing; if the ONU is in power-off alarm, the step 103 is proceeded to.

Step 103: adding ONU power-off alarm into a buffer queue;

and creating a First-in First-out (FIFO) queue, and sequentially adding the ONU power-off alarm into the queue according to the reporting time of the alarm. Because the queue is a first-in first-out queue, the alarm at the head of the queue occurs at the earliest time, and the alarm at the tail of the queue occurs at the latest time.

Step 104: circularly checking whether the difference value between the occurrence time of the first alarm of the queue and the current detection time reaches a set threshold value;

and acquiring the occurrence time of the alarm at the head of the cache queue, and calculating whether the time difference between the occurrence time and the current detection time reaches a set processing time slice threshold value. If the time difference does not reach the threshold, go to step 105; if the time difference meets or exceeds the threshold, proceed to step 106.

Based on a large amount of laboratory data, it is appropriate to set the processing time slice threshold to 0.1 seconds. Further, in order to ensure the accuracy of the detection method in the actual engineering, the threshold is stored in a configuration file, and in the actual engineering, the threshold can be adjusted according to the actual situation of the site.

Step 105: detecting a given time of process dormancy;

in step 104, if the time difference between the head and the tail of the queue is smaller than the set threshold value, the queue is dormant for a given time.

It is appropriate to detect that the process sleep time is between one third and one half of the processing time slice threshold based on a large amount of laboratory data. Further, in order to ensure the accuracy of the detection method in the actual engineering use, the sleep time is stored in a configuration file, and in the actual engineering, the sleep time can be adjusted according to the actual situation of the site.

Step 106: the ONU power-off alarm is moved into a processing queue;

and recording the occurrence time of the ONU power-off alarm at the head of the cache queue in the step 104 as A, recording the threshold value of the processing time slice as B, sequentially inquiring the ONU power-off alarm record at the head of the cache queue, and marking the alarm occurrence time of the record as T. If A + B > -T, then remove the alarm buffer queue head and add it to the processing queue. And sequentially processing the current head records of the buffer queue until the judgment condition is not met.

Step 107: grouping the alarms in the processing queue according to the PON where the ONU is located;

and grouping the ONUs in the processing queue according to the PON ports to which the ONUs belong, wherein each PON port is one group. And sequentially processing the PON port packets in the processing queue until all the PON ports are processed. The processing logic for each PON, as shown in step 108.

Step 108: judging whether the packet has only one ONU or not;

for each PON port packet, firstly, whether the special situation is present is judged, namely, only one ONU is under the PON port. If there is only one ONU in the PON port packet, go to step 110; if the number of ONUs in the PON port is greater than 1, go to step 109.

Step 109: judging whether the alarm is a PON port cell power-off alarm;

recording the total number of ONUs in the PON port packet as a, then querying the number of online ONUs under the PON port from the system before the processing time slice, and recording as B, if a is equal to B, it indicates that the online ONUs under the PON port are powered off simultaneously in one processing time slice, and then it is determined that the PON port cell is powered off, and step 110 is performed; otherwise, go to step 110.

Step 110: a non-PON port cell power-off alarm directly forwards an original alarm to a network manager;

for the common situation of non-PON port cell power failure, the alarm original state reported by the original ONU is directly forwarded to the network management.

Step 111: discarding the ONU power-off alarm;

for the situation of power-off alarm of the PON port cell, alarm suppression processing is required. The ONU power-off alarm reported by each ONU under the PON port needs to be discarded.

Step 112: reporting a power-off alarm of the PON port cell to a network manager;

and generating a new PON port cell power-off alarm by the OLT network element, and reporting the alarm to the network manager.

Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.

The embodiment of the invention also provides a storage medium. Optionally, in this embodiment, the storage medium may be configured to store program codes for executing the steps of the method of the above embodiment:

optionally, in this embodiment, the storage medium may include, but is not limited to: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

Alternatively, in the present embodiment, the processor executes the method of the above-described embodiment according to the program code stored in the storage medium.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A passive optical network alarm detection method is characterized by comprising the following steps:

comparing the difference value between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT with a preset time slice threshold value, and determining that the ONU meets the power-off alarm requirement under the condition that the difference value reaches the preset time slice threshold value;

2. The method according to claim 1, wherein determining that the cell in which the PON is located is powered off when the comparison result meets a preset requirement comprises:

3. The method of claim 1, further comprising:

and adding the power failure alarm reported by the ONU into the created queue, circularly detecting the difference value between the receiving time in the power failure alarm at the head part of the queue and the generating time in the power failure alarm record, and removing the power failure alarm at the head part of the queue under the condition that the difference value reaches the preset time slice threshold value.

4. The method of claim 3, further comprising:

grouping the power-off alarms in the queue according to the PON port to which the ONU belongs;

and sequentially performing the cyclic detection according to the grouping.

5. The method according to any of claims 1 to 4, wherein in case it is determined that the cell in which the PON is located is powered down, the method further comprises at least one of:

discarding the reported power failure alarm;

6. A passive optical network alarm detection device, comprising:

the comparison module is used for comparing the difference value between the generation time of the power-off alarm and the receiving time of the power-off alarm received by the OLT with a preset time slice threshold value, and determining that the ONU meets the power-off alarm requirement under the condition that the difference value reaches the preset time slice threshold value;

7. The apparatus of claim 6, wherein the determining module comprises:

8. The apparatus of claim 6, wherein the comparison module comprises:

9. The apparatus of claim 8, further comprising:

10. The apparatus of any one of claims 6 to 9, further comprising: