WO2016061782A1 - Optical fiber troubleshooting method, device and system - Google Patents

Abstract

Disclosed in an embodiment of the present invention is an optical fiber troubleshooting method, the method comprising: a primary port sends a dynamic bandwidth allocation (DBA) authorization window to an optical network terminal (ONT) connected therewith to turn on an optical module of a spare port; an optical time domain reflectometer (OTDR) test is performed by the spare port, and when the OTDR test is completed, a test completion message is sent to the primary port; when the primary port receives the test completion message, a second DBA authorization message is sent to the ONT. The embodiment of the present invention sends a DBA authorization window message to an ONT via a primary port, and although the window message may cause a slight increase in the service time delay, the message improves user experience and efficiency compared with service packet loss and packet error due to a window being opened directly by a spare port to send a test light in the prior art.

Description

Optical fiber fault diagnosis method, device and system Technical field

The present invention relates to the field of optical communications, and in particular, to a fiber fault diagnosis method, device and system.

Background technique

For the diagnosis of fiber faults, the common method in the industry is to use an Optical Time Domain Reflectometer (OTDR) to detect and locate faults in the optical network. The basic principle of the optical time domain reflectometer is to use the retroreflection generated when the light wave propagates in the optical fiber network, and to inject a certain wavelength of light into the optical fiber network, and then reflect the energy of the corresponding reflected light to reflect the optical network. The situation is as an example of the prior art 1 of FIG. 1490nm is the downward light, 1310nm is the upward light, 1310nm light can penetrate the thin film filter (TFF) into the b channel and is detected by the photo detector (Photo Detector, PD for short), while the 1490nm downstream light carries the OTDR. The test signal passes through the TFF and then enters the passive optical network (PON) network from the a path. After the reflected optical signal of the PON network returns to the a channel, it is reflected by the TFF filter and then passes through the splitter. To the d channel, it is detected by the 1490nm Optical Detector (PD). Since the speed of light in the fiber is predictable, the curve of the reflected light intensity with time corresponds to the reflected light intensity with distance. The curve is changed, so it is possible to judge what fault has occurred at a long distance based on the change in the reflected light intensity. For example, measuring a large reflected light energy means that the fiber breakage may occur at this specific distance. If an energy attenuation is detected, it means that the fiber bending problem may occur at the specific distance, and then the fault occurs. Troubleshoot.

Figure 2 is a scheme of the Type B protection group described in the standard G 984.1. Figure 3 is a scheme of the Type C protection group described in G 984.1 of the standard. When a fault occurs on the trunk fiber of the primary port of the protection group, the port on the OLT detects a fault alarm. At this time, the protection group switch is triggered. After the protection group is switched to the standby port, the standby port starts the downlink illumination state, completes the processing of the ONU or ONT and jumps to the normal working state at the specified time. If the switchover is successful, all services on the ONT of the PON port will be restored. In the configured Type B protection group, because the primary and backup ports are connected by the optical splitter, in order to prevent the illumination conflict, only the primary port emits light during normal operation, and the standby port cannot emit light.

Since the standby port does not illuminate during the running process, it is the master of the alternate port of the Type B protection group. The specific conditions of the dry fiber cannot be obtained directly. However, the specific condition of the trunk fiber of the standby port directly affects whether the protection group can be successfully switched. Therefore, it is necessary to provide a method for diagnosing whether the trunk fiber of the standby port is normal during operation.

The prior art provides a fault diagnosis method, which is: directly starting the OTDR test of the protection port of the protection group, and determining whether the trunk fiber of the standby port is normal through the test result. However, the shortcomings of the solution are also obvious. The direct port illumination may conflict with the main port, causing the ONT service to be abnormal or even the ONT to go offline.

Summary of the invention

In view of this, an object of the present invention is to provide a method, apparatus, and system for optical fiber fault diagnosis that does not affect the normal operation of an ONT.

In a first aspect, an embodiment of the present invention provides a fiber fault diagnosis method, where the method includes: an active port sends a dynamic bandwidth allocation DBA authorization window to an optical network terminal ONT connected thereto, and activates an optical module of the standby port; The port performs an optical time domain reflectometer OTDR test; when the OTDR test is completed, the primary OLT sends a second DBA grant message to the ONT.

With reference to the first aspect, in a first possible implementation manner of the first aspect, the optical module of the standby port is specifically configured to: if the primary port and the standby port are located on the same board, when the primary port sends the DBA to the ONT When an empty window is authorized, the optical module of the standby port is enabled by the board; if the primary port and the standby port are on different boards, when the primary port sends a DBA authorized window to the ONT, the main control board is turned on. Optical module of the alternate port.

With reference to the first aspect, in a second possible implementation manner of the first aspect, when the OTDR test is completed, the primary OLT sends a second DBA authorization message to the ONT, specifically, when When the OTDR test is completed, the standby port sends a notification message of the end of the test to the primary port; when the primary port receives the notification message, it sends a DBA authorization message to the ONT.

In a second aspect, a central office device is applied to a passive optical network system, where the device includes two first ports, a second port, and a control module, where the first port is used to connect to an optical network connected thereto The terminal ONT sends a dynamic bandwidth allocation DBA authorization window; the control module is used to enable the optical module of the second port; the second port is used for the optical time domain reflectometer OTDR test; the first port is also used for When the OTDR test is completed, a second DBA authorization message is sent to the ONT.

With reference to the second aspect, in a first possible implementation manner of the second aspect, when the primary port and the standby port are located on the same board, the control module is located on the board.

With reference to the second aspect, in a second possible implementation manner of the second aspect, when the primary port and the standby port are located on the same board, the control module is a main control board.

In conjunction with the second aspect, in a third possible implementation manner of the second aspect, the second port is further configured to send a notification message of the end of the test to the active port when the OTDR test is completed.

With reference to the second aspect, in a fourth possible implementation manner of the second aspect, the first port is further configured to: when the OTDR test is completed, send a second DBA authorization message to the ONT, specifically including When the first port receives the test end message from the second port, the dynamic bandwidth grant message is sent to the ONT.

The third aspect is a fiber fault diagnosis system, where the system includes a central office device, an optical distribution network ODN, and an optical network terminal ONT, where the central office device includes any possible implementation manner of the second aspect and the second aspect. Said device.

The optical fiber fault diagnosis method provided by the embodiment of the present invention sends a DBA authorized air window message to the ONT through the primary port, and the empty window message causes a small increase in the service delay, but is smaller than the prior art due to the standby port. Directly opening the window to send test light results in loss of service and wrong packets, which improves the user experience and improves efficiency.

DRAWINGS

In order to more clearly illustrate the technical solutions of the present invention, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, which are common in the art. For the skilled person, other drawings can be obtained from these drawings without any creative work.

Figure 1 is a schematic diagram of the implementation of the built-in optical time domain reflectometer EOTDR function;

2 is a schematic structural diagram of a Type B protection group;

3 is a schematic structural diagram of a Type C protection group;

4 is an interaction diagram of a fiber fault diagnosis method according to an embodiment of the present invention;

5 is a schematic diagram of an introduction of an OTDR;

FIG. 6 is a schematic structural diagram of a central office device according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Type B and Type C GPON line protection modes are defined in ITU-T G984.1, as shown in Figure 2 and Figure 3, respectively. Among them, the protection range of Type B from the OLT to the trunk fiber of the optical splitter needs to provide a 2:N splitter, and the redundant GPON interface must also be provided on the OLT. The Type C mode supports network-wide protection. Two 1:N splitters are required. Redundant GPON interfaces must be provided on the OLT and ONT. This method is more reliable and the network construction cost is higher than Type B. .

In the latest version of the GPON standard in 2008, the OLT's dual-homing protection mechanism is newly added, mainly to solve the OLT's fault protection. It is required that each ONT be dual-homed to two different OLT devices, and two OLTs are established through the network management system. The communication channels of the two OLTs complete the protection switching. The conditions for the trigger protection include the interruption of the backbone fiber connected to the OLT side, the high bit error rate on the link, the failure of the GPON interface or the board, and the failure of the OLT device.

When there is a fault such as fiber breakage in the trunk fiber, all ONTs will receive an alarm, and the ONT will be adjusted from the normal state to the suspended state. When the ONT enters the suspended state, the ONT stops the uplink data transmission. At this time, an alarm is detected on the OLT, and the OLT will trigger the GPON port switch. After the system is switched to the standby port, the standby GPON interface starts the downlink illuminating state and broadcasts a suspend message to notify all ONTs to enter the ranging state, complete the ranging at a specified time, and smoothly jump to the normal working state. The OLT performs data verification after the ONT ranging is completed. If the database of the standby interface and the database of the primary port are the same, all services on the ONT will be restored.

As the standby port of the GPON Type B protection group does not directly receive the fault, the specific conditions of the trunk fiber of the standby port can directly affect whether the protection group can be successfully switched. Provides a method for diagnosing whether the trunk fiber of the alternate port is normal during operation.

Embodiment 1

Referring to FIG. 4, an embodiment of the present invention provides a method for optical fiber fault diagnosis, which includes:

Step 401: The active port sends a dynamic bandwidth allocation DBA authorization window to the ONT connected thereto, and starts the optical module of the standby port.

Further, the DBA authorized air window message refers to not allocating uplink bandwidth or allocating 0 megabit bandwidth for the ONT, which means that the ONT does not send the uplink optical signal, and suspends the transmission of the service.

Further, if the primary port and the backup port are on the same card, when the primary port sends a DBA authorized window to the ONT, the optical module of the standby port is enabled by the board;

If the primary port and the standby port are on different boards, the main control board is responsible for enabling the optical module of the standby port when the primary port sends a DBA authorized window to the ONT.

Step 402: Perform an OTDR test on the standby port. After the OTDR test is completed, send a test end message to the active port.

It should be noted that the OTDR device is divided into an external OTDR and a built-in OTDR, as shown in FIG. The external OTDR refers to the large-scale independent OTDR equipment connected to the optical network through the optical splitter for measurement and monitoring. The OTDR transmitting and receiving functions are implemented outside the optical module. Built-in OTDR refers to the integration of OTDR transmit and receive functions into the optical module for miniaturization integration. The built-in OTDR is also called Embedded Optical OTDR (EOTDR), because EOTDR generally uses OLT for reuse. The optical module LD (Laser Diode) or PD (Photo Detector) is a hot topic because it is cheaper and more integrated than the external method.

This method can be applied to both the built-in OTDR and the external OTDR.

When the built-in OTDR is used, the built-in OTDR emits test light waves, and the state of the optical network is reflected by measuring the amount of reflected light energy of the test light wave in the optical network.

When an external OTDR is used, the external OTDR emits a test light wave, and the state of the optical network is reflected by measuring the amount of reflected light energy of the test light wave in the optical network.

Step 403: When receiving the test end message, the primary port sends a dynamic bandwidth allocation authorization message to the ONT.

It should be noted that the DBA authorization message is used to allocate an uplink bandwidth to the ONT.

The above-mentioned primary port refers to the port that is currently working normally. The standby port refers to the port used for protection switching and redundancy backup, or the standby port can be understood as the port that is not working normally.

In the embodiment of the present invention, the DBA authorized air window message is sent to the ONT through the primary port. Although the empty window message causes a small increase in the service delay, the test light is directly sent through the window according to the prior art. The consequences of packet loss and error packets improve the user experience and improve efficiency.

Embodiment 2

The present invention provides a central office device for use in a passive optical network system. As shown in FIG. 6, the central office device 600 includes a first port 601, a second port 602, and a control module 603, a first port 601 and a The two ports 602 are respectively connected to the control module 603;

The first port 601 is configured to send a DBA authorized air window to the optical network terminal ONT connected thereto; the control module 603 is configured to enable the optical module of the second port; and the second port 602 is configured to perform an OTDR test of the optical time domain reflectometer; The first port 601 is further configured to send a second DBA authorization message to the ONT when the OTDR test is completed.

The control module is located on the board, and the control port is located on the same board.

When the primary port and the standby port are located on the same board, the control module is a main control board.

Further, the second port is further configured to send a notification message of the end of the test to the active port when the OTDR test is completed.

The first port is further configured to: when the OTDR test is completed, send a second DBA authorization message to the ONT, specifically:

Sending a dynamic bandwidth grant message to the ONT when the first port receives a message from the second port that the test ends.

The central office device can be used to perform the method steps of the embodiment. The description and explanation of the description of the embodiment are also applicable to the second embodiment.

In the embodiment of the present invention, the DBA authorized air window message is sent to the ONT through the primary port. Although the empty window message causes a small increase in the service delay, the test light is directly sent through the window according to the prior art. The consequences of packet loss and error packets improve the user experience and improve efficiency.

Embodiment 3

The embodiment of the present invention provides a PON system of a passive optical network, including an OLT and an ONT. The networking structure of the PON system may be a Type B protection group or a Type C protection group as shown in FIG. 2 or FIG. 3. The structure of the OLT can be as described in Embodiment 2. The PON system can be used to perform the method steps as described in one embodiment.

The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It is the scope of protection of the present invention.

Claims (9)

A fiber fault diagnosis method, the method comprising: The active port sends a dynamic bandwidth allocation DBA authorization window to the optical network terminal ONT connected thereto, and the optical module of the standby port is enabled; The standby port performs an optical time domain reflectometer OTDR test, and after the OTDR test is completed, sends a test end message to the primary port; And when the primary port receives the end message, sending a second DBA authorization message to the ONT. The method of claim 1 , wherein the step of opening the optical module of the standby port comprises: If the primary port and the backup port are located on the same card, when the primary port sends a DBA authorized window to the ONT, the optical module of the standby port is enabled by the board; If the primary port and the standby port are on different boards, when the primary port sends a DBA authorized window to the ONT, the optical module of the standby port is enabled by the main control board. The method according to claim 1, wherein the primary port is a currently working port, and the standby port is a port for performing redundancy backup or a port that is not currently working normally. A central office device is applied to a passive optical network system, where the device includes two first ports, a second port, and a control module, where a first port, configured to send a dynamic bandwidth allocation DBA authorization window to the optical network terminal ONT connected thereto; a control module, configured to enable an optical module of the second port; a second port for performing an optical time domain reflectometer OTDR test; The first port is further configured to send a second DBA authorization message to the ONT when the OTDR test is completed. The device according to claim 4, wherein the control module is located on the board when the primary port and the backup port are located on the same board. The device according to claim 4, wherein said primary port and said device The port is located on the same board, and the control module is the main control board. The device according to claim 4, wherein the second port is further configured to send a notification message of the end of the test to the primary port when the OTDR test is completed. The device according to claim 7, wherein the first port is further configured to: when the OTDR test is completed, send a second DBA authorization message to the ONT, specifically: Sending a dynamic bandwidth grant message to the ONT when the first port receives a message from the second port that the test ends. A fiber-optic fault diagnosis system, comprising: a central office device, an optical distribution network ODN, and an optical network terminal ONT, wherein the central office device comprises the device according to any one of claims 4-8.

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