Communication method and system of vehicle-mounted passive optical network

Abstract

The invention discloses a communication method and system of a vehicle-mounted passive optical network, and relates to the field of data transmission of optical communication. Establishing a communication relationship between the ONU and the standby OLT; the main OLT sends main and standby switching information to the standby OLT through a special main and standby switching channel; and the standby OLT confirms the ONU needing communication according to the main and standby switching information. On the basis of adding the standby OLT, the main and standby switching information is received and transmitted through the special main and standby switching channel, so that the redundancy protection range is expanded to the OLT domain control equipment, and the OLT domain control single-point fault can be avoided; moreover, the special main and standby switching channels can avoid the failure or timeout of protection switching caused by the transmission of the main and standby switching information from a communication channel for message transmission before the fault, thereby guaranteeing the timely transmission of the main and standby switching information, achieving the seamless switching between the main and standby OLT, and remarkably improving the switching efficiency and reliability.

Description

Technical Field

[0001] The present invention relates to the field of data transmission in optical communication, and in particular to a communication method and system for a vehicle-mounted passive optical network. Background Art

[0002] With the development of intelligent connected vehicles, traditional copper wire communication is gradually being replaced by optical fiber communication, a trend known as "optical fiber replacing copper wire". In-vehicle optical communication technology is increasingly being used in the field of intelligent connected vehicles due to its advantages such as high bandwidth, low latency, anti-electromagnetic interference and lightweight.

[0003] Due to its unique advantages, vehicle-mounted passive optical network technology is becoming an important driving force for the development of intelligent connected vehicles, helping to achieve a safer, more efficient and smarter driving experience.

[0004] See also Figure 1 As shown in the figure, the traditional passive optical network redundancy solution (illustrated by Type B solution) is generally composed of OLT (Otical Lne Trminal, optical line terminal) and several ONUs (Optical Network Units, optical network units). The OLT includes several optical modules and corresponding PON MAC chips (Passive Optical Network Medium / Media Access Contro, passive optical network media access control, that is, a processing chip for PON signal data). Each optical module and its PON MAC chip correspond to a PON interface. Taking two optical modules as an example, the OLT communicates with several ONUs (ONU1~ONUN) through a 2:N splitter.

[0005] When the above solution is used, the PON interface of the OLT is protected by active / standby switching. When the primary link (e.g., PON interface 1) fails, it will switch to the standby link (e.g., PON interface 2) for communication. However, if the OLT itself fails (i.e., a single point failure occurs in the OLT), all ONUs will not work. Summary of the invention

[0006] In view of the defects existing in the prior art, the technical problem solved by the present invention is: how to realize the active / standby switching of OLT through a dedicated communication channel, thereby forming redundant protection of OLT through efficient switching.

[0007] To achieve the above objectives, in a first aspect, an embodiment of the present application provides a communication method for a vehicle-mounted passive optical network, the method comprising the following steps: establishing a communication relationship between the ONU and the backup OLT; the active OLT sends active-standby switching information to the backup OLT through a dedicated active-standby switching channel; the backup OLT confirms the ONU that needs to communicate based on the active-standby switching information.

[0008] In combination with the first aspect, in one embodiment, the active-standby switching channel is a data transmission channel between the main control board and the line card; the process of sending active-standby switching information to the standby OLT through the dedicated active-standby switching channel includes: the line card board of the active OLT sends the active-standby switching information to the main control board through the active-standby switching channel, and the main control board of the active OLT sends the active-standby switching information to the main control board of the standby OLT.

[0009] In combination with the first aspect, in one implementation, the process of determining the standby OLT of the ONU that needs to communicate according to the active / standby switching information includes:

[0010] The active OLT sends active / standby switching information to all standby OLTs. The standby OLTs that receive the active / standby switching information send their own status information to the control end. The control end designates a standby OLT in normal status to confirm the ONU that needs to communicate based on the active / standby switching information.

[0011] or:

[0012] All standby OLTs periodically send their own status information to the control end. After receiving the standby OLT's own status information, the control end updates the status of the standby OLT. After the main control board of the main OLT receives the master-standby switching information sent by the line card board, it requests the control end to transmit the master-standby switching information. The control end selects a standby OLT with normal status and feeds it back to the active OLT. The main control board of the active OLT sends the master-standby switching information to the standby OLT fed back to the control end.

[0013] In combination with the first aspect, in one implementation, the active / standby switching information includes: an active / standby switching information identifier, a destination MAC address, and a source MAC address; the destination MAC address is a MAC address of a main control board of the active OLT, and the source MAC address is a NAC address of a line card board of the active OLT;

[0014] The process of the standby OLT confirming the ONU that needs to communicate according to the active-standby switching information includes: after the standby OLT parses the active-standby switching information, all ONUs that communicate with the line card board of the active OLT are determined as ONUs that need to communicate according to the source MAC address, and the standby OLT transmits data to all ONUs that need to communicate through the line card board.

[0015] In combination with the first aspect, in one implementation, the active-standby switching channel is a layer 2 data channel between a main control board and a line card board, and adopts a data link layer private protocol.

[0016] In combination with the first aspect, in an implementation manner, the method further includes the following steps: after the active OLT is normal, the active OLT sends its own status information to the control end; and the control end controls the standby OLT to switch to the active OLT.

[0017] In combination with the first aspect, in one implementation, the method further includes the following steps: the active OLT synchronizes communication information with the ONUs to all standby OLTs.

[0018] In combination with the first aspect, in an implementation manner, the process of establishing a communication relationship between the ONU and the standby OLT includes: registering the ONU on a PON interface of the OLT.

[0019] In a second aspect, an embodiment of the present application provides a communication system for a vehicle-mounted passive optical network, the system comprising a primary OLT and a backup OLT provided in the first aspect.

[0020] In combination with the second aspect, in one implementation, the OLT includes a main control board and a line card board, the main control board includes a service data exchange module, and the line card board includes a control module; the communication channel between the service data exchange module and the control module includes the active / standby switching channel;

[0021] The control module is used to: send active / standby switching information to the service data exchange module through the active / standby switching channel when the OLT is abnormal; and transmit data to the ONU that needs to communicate confirmed by the service data module;

[0022] The service data exchange module is used to: transmit and receive active / standby switching information; confirm the ONU that needs to communicate based on the received active / standby switching information and inform the control module; and report the OLT's own status.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] The present invention, on the basis of adding a spare OLT, sends and receives the master-slave switching information through a dedicated master-slave switching channel, thereby expanding the redundant protection range to the OLT domain control device, which can not only avoid the single point failure of the OLT domain control; but also the dedicated master-slave switching channel can avoid the protection switching failure or timeout caused by the transmission of the master-slave switching information from the communication channel for message transmission before the failure, thereby ensuring the timely transmission of the master-slave switching information, thereby realizing the seamless switching between the master and standby OLTs, and significantly improving the switching efficiency and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic diagram of the architecture of a passive optical network in the prior art;

[0027] Figure 2 This is a schematic diagram of the logical structure of OLT;

[0028] Figure 3 A schematic diagram of OLT transmitting active / standby switching information in an embodiment of the present application;

[0029] Figure 4 This is a schematic diagram of the architecture of a communication system of a vehicle-mounted passive optical network in an embodiment of the present application;

[0030] Figure 5 This is a schematic diagram of the hardware structure of the communication equipment of the vehicle-mounted passive optical network involved in the embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0032] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0033] First, the research and development process of this application is briefly described.

[0034] If the primary and standby switching of OLT is to be performed, it can be achieved by adding OLTs. However, after adding OLTs, if the existing communication channels of OLTs are still used for switching message communication between OLTs, the existing communication channels may be blocked because they are still sending data or for other reasons. In this way, even if the primary and standby switching of OLTs is achieved, the switching speed will be slow. The important requirement for primary and standby switching is to perform the primary and standby switching efficiently.

[0035] On this basis, in the first aspect, an embodiment of the present application provides a communication method for a vehicle-mounted passive optical network, the steps of which include: establishing a communication relationship between the ONU in use and at least one backup OLT; when the main OLT is abnormal, the main OLT sends main-backup switching information to at least one backup OLT through a dedicated main-backup switching channel; after the backup OLT confirms the ONU that needs to communicate based on the main-backup switching information, it transmits data with the ONU.

[0036] It can be seen that, based on adding a backup OLT, the present invention sends and receives the master-slave switching information through a dedicated master-slave switching channel, thereby expanding the redundant protection range to the OLT domain control device, which can not only avoid the single point failure of the OLT domain control; but also the dedicated master-slave switching channel can avoid the protection switching failure or timeout caused by the transmission of the master-slave switching information from the communication channel for message transmission before the failure, thereby ensuring the timely transmission of the master-slave switching information, thereby realizing seamless switching between the master and standby OLTs, and significantly improving the switching efficiency and reliability.

[0037] The following specifically describes the master / slave switching channel and the process of transmitting the master / slave switching information in the above method.

[0038] First, the composition structure of OLT is described.

[0039] See also Figure 2 As shown, the OLT includes a main control board, a line card board and an uplink board.

[0040] The main control board is used to: realize the overall control and management of the functions of the domain controller, manage the configuration of each ONU and aggregate ONU data, and then exchange and forward it.

[0041] The line card board is used to provide a PON interface to access ONU data. The main control board and the line card board transmit normal information (such as ONU data messages, business configuration related to PON protection, etc.) through the business communication channel.

[0042] The uplink board is used to: provide an uplink interface, used for cascade networking between devices, and connect the control end; both the line card board and the uplink board communicate with the main control panel through the OLT internal bus. The passive optical network in this embodiment is a vehicle-mounted passive optical network, so the control end is the central computing terminal of the whole vehicle, and the ONU is the corresponding components such as ECU and sensors.

[0043] On this basis, the active / standby switching channel in the above method is a data transmission channel established between the main control board and the line card.

[0044] The process of sending the master-slave switching information to at least one standby OLT through a dedicated master-slave switching channel in the above method includes: the line card board of the active OLT sends the master-slave switching information to the main control board through the active-slave switching channel, and the main control board of the active OLT sends the master-slave switching information to the main control board of the standby OLT.

[0045] At the same time, the process of receiving the active / standby switching information and confirming the standby OLT of the ONU that needs to communicate according to the active / standby switching information can be any one of the following two methods:

[0046] (1) The active OLT sends active / standby switching information to all standby OLTs. The standby OLTs that receive the active / standby switching information send their own status information to the control end. The control end designates a standby OLT in normal status to confirm the ONU that needs to communicate based on the active / standby switching information. Other standby OLTs do not process the active / standby switching information (they may discard and / or process the message).

[0047] The advantage of process (1) is that the status of the standby OLT is confirmed during the switching process, and the accuracy of the status confirmation is high. However, the interaction process between the standby OLT and the control end after receiving the active / standby switching information is increased, which reduces the switching efficiency.

[0048] (2) All standby OLTs periodically send their own status information to the control end. After receiving the standby OLT's own status information, the control end updates the standby OLT's status. After receiving the master-slave switching information sent by the line card board, the main control board of the master OLT requests the control end to transmit the master-slave switching information. The control end selects a standby OLT with normal status and feeds it back to the master OLT. The main control board of the master OLT sends the master-slave switching information to the standby OLT fed back by the control end.

[0049] The advantage of process (2) is that when switching is required, the standby OLT directly sends the active-standby switching information based on the feedback from the control end, and the standby OLT processes it immediately after receiving it, thereby improving the switching efficiency. However, compared with process (1), the status of the standby OLT in process (2) will be delayed due to periodic transmission, that is, the status of the standby OLT is not accurate enough.

[0050] In actual applications, specific processes can be selected for execution based on different needs and usage scenarios.

[0051] In one embodiment, the active / standby switching information in the above method specifically includes: active / standby switching information identifier (used to identify active / standby switching information), destination MAC address, source MAC address, TPID, VLAN, Ethernet type, message type, protection group ID, reserved bytes, and messages for inter-board communication, etc. The destination MAC address is the MAC address of the main control board of the above-mentioned active OLT, and the source MAC address is the NAC address of the line card board of the above-mentioned active OLT; TPID and VLAN form a VLAN Tag; the Ethernet type defines this type of message by itself; the message type can be used to define the message as a PON redundant protection message. The protection group ID is the serial number of the protection group. The message for inter-board communication includes the port number, synchronization message, etc.

[0052] On this basis, after the standby OLT confirms the ONU that needs to communicate according to the master-slave switching information, the process of data transmission with the ONU includes: after the standby OLT parses the master-slave switching information, it determines all ONUs that communicate with the line card board of the above-mentioned active OLT as the ONUs that need to communicate according to the source MAC address, and the standby OLT transmits data to all ONUs that need to communicate through the line card board.

[0053] In one embodiment, the active-standby switching channel in the above method is a dedicated Layer 2 data channel for PON redundancy protection between the main control board and the line card board, which adopts a data link layer private protocol and has high security and transmission efficiency.

[0054] In one embodiment, the method further includes the following steps: after the active OLT is normal, it sends its own status information to the control end; the control end controls the standby OLT to switch to the active OLT, and the switching method is the reverse process of the active OLT sending the active-standby switching information to the standby OLT; that is, the standby OLT sends the active-standby switching information to the active OLT through the active-standby switching channel; after the active OLT confirms the ONU that needs to communicate based on the active-standby switching information, it transmits data with the ONU.

[0055] In one embodiment, the method further includes the following steps: the active OLT periodically synchronizes communication information with the ONU to all standby OLTs (communication information includes dynamic information such as ONU status, and the specific content belongs to common knowledge in the art), so that when the active OLT fails, the standby OLT receives the active-standby switching information and can work immediately.

[0056] In one embodiment, the process of establishing a communication relationship between the ONU in use and at least one standby OLT includes: registering the ONU on the PON interface of the OLT.

[0057] It should be noted that the primary and backup OLTs mentioned above are examples corresponding to the specific situations above and are not limiting. In actual applications, the OLT in use is the primary OLT and the OLT not in use is the backup OLT.

[0058] In a second aspect, an embodiment of the present application further provides a vehicle-mounted passive optical network communication system, the system comprising a primary OLT and at least one backup OLT.

[0059] The main OLT is used to: implement the functions of the main OLT in the above method;

[0060] The standby OLT is used to: implement the function of the standby OLT in the above method.

[0061] For details, see Figure 3As shown, the OLT includes a main control board and a line card board. The main control board includes a CPU control module and a service data exchange module. The line card board includes a control module (a main control module and a standby control module) and a PON protocol message transceiver processing module.

[0062] The CPU control module, the control module and the PON protocol message transceiver processing module (for sending and receiving ONU communication messages) are conventional modules, and their specific functions are not described in detail here.

[0063] The communication channel between the service data exchange module and the control module includes a conventional service communication channel and the above-mentioned primary and standby switching channel.

[0064] The control module is used to:

[0065] (1) When the OLT is abnormal, the active / standby switching information is sent to the service data exchange module through the active / standby switching channel;

[0066] (2) Data is transmitted to the ONU that needs to communicate as confirmed by the service data module.

[0067] The business data exchange module is used to:

[0068] (1) Transmit and receive active / standby switchover information;

[0069] (2) confirming the ONU that needs to communicate based on the received master / slave switching information and informing the control module;

[0070] (3) Reporting the OLT's own status.

[0071] In one embodiment, the application scenario is a vehicle-mounted passive optical network, see Figure 4 As shown, in this embodiment, the main OLT is OLT1, and the backup OLT is one (OLT2); as for the number of backup OLTs, considering the use cost and failure conditions, generally one is used, because in the process of using the backup OLT, the main OLT can generally be repaired, and basically the main and backup OLTs will not fail at the same time.

[0072] The system also includes a splitter and N ONUs. The splitter is a 2:N splitter. The ONUs are connected to ECUs, sensors and other related equipment.

[0073] In a third aspect, an embodiment of the present application provides a communication device for a vehicle-mounted passive optical network. The communication device for the vehicle-mounted passive optical network may be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0074] Reference Figure 5 , Figure 5The hardware structure diagram of the vehicle-mounted passive optical network communication device involved in the embodiment of the present application is shown in FIG. In the embodiment of the present application, the vehicle-mounted passive optical network communication device may include a processor, a memory, a communication interface, and a communication bus.

[0075] The communication bus may be of any type and is used to interconnect the processor, the memory, and the communication interface.

[0076] The communication interface includes input / output (I / O) interface, physical interface and logical interface, etc., which are used to realize the interconnection of devices inside the communication equipment of the vehicle-mounted passive optical network, and the interface used to realize the interconnection between the communication equipment of the vehicle-mounted passive optical network and other devices (such as other computing devices or user equipment). The physical interface can be an Ethernet interface, a fiber optic interface, an ATM interface, etc.; the user equipment can be a display, a keyboard, etc.

[0077] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0078] The processor may be a general-purpose processor, which may call the communication program of the vehicle-mounted passive optical network stored in the memory and execute the communication method of the vehicle-mounted passive optical network provided in the embodiment of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the communication program of the vehicle-mounted passive optical network is called may refer to the various embodiments of the communication method of the vehicle-mounted passive optical network of the present application, which will not be repeated here.

[0079] Those skilled in the art will understand that Figure 5 The hardware structure shown in the figure does not constitute a limitation on the present application, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0080] In a fourth aspect, an embodiment of the present application also provides a computer-readable storage medium.

[0081] The computer-readable storage medium of the present application stores a communication program of a vehicle-mounted passive optical network, wherein when the communication program of the vehicle-mounted passive optical network is executed by a processor, the steps of the communication method of the vehicle-mounted passive optical network as described above are implemented.

[0082] Among them, the method implemented when the communication program of the vehicle-mounted passive optical network is executed can refer to the various embodiments of the communication method of the vehicle-mounted passive optical network of the present application, and will not be repeated here.

[0083] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are only for description and do not represent the advantages or disadvantages of the embodiments.

[0084] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.

[0085] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.

[0086] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.

[0087] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0088] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.

[0089] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.

[0090] The above are only specific implementations of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the embodiments of the present invention, and these modifications or replacements should be included in the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention shall be based on the protection scope of the claims.

Claims

1. A communication method for a vehicle-mounted passive optical network, characterized in that: The method comprises the following steps: establishing a communication relationship between the ONU and the standby OLT; the active OLT sending active / standby switching information to the standby OLT through a dedicated active / standby switching channel; and the standby OLT confirming the ONU that needs to communicate according to the active / standby switching information.

2. The communication method of the vehicle-mounted passive optical network according to claim 1, characterized in that: The active-standby switching channel is a data transmission channel between the main control board and the line card; the process of sending active-standby switching information to the standby OLT through the dedicated active-standby switching channel includes: the line card board of the active OLT sends the active-standby switching information to the main control board through the active-standby switching channel, and the main control board of the active OLT sends the active-standby switching information to the main control board of the standby OLT.

3. The communication method of the vehicle-mounted passive optical network as claimed in claim 2, characterized in that: The process of determining the standby OLT of the ONU that needs to communicate according to the active / standby switching information includes: The active OLT sends active / standby switching information to all standby OLTs. The standby OLTs that receive the active / standby switching information send their own status information to the control end. The control end designates a standby OLT in normal status to confirm the ONU that needs to communicate based on the active / standby switching information. or: All standby OLTs periodically send their own status information to the control end. After receiving the standby OLT's own status information, the control end updates the status of the standby OLT. After the main control board of the main OLT receives the master-standby switching information sent by the line card board, it requests the control end to transmit the master-standby switching information. The control end selects a standby OLT with normal status and feeds it back to the active OLT. The main control board of the active OLT sends the master-standby switching information to the standby OLT fed back to the control end.

4. The communication method of the vehicle-mounted passive optical network as claimed in claim 2, characterized in that: The master-slave switching information includes: a master-slave switching information identifier, a destination MAC address, and a source MAC address; the destination MAC address is the MAC address of the main control board of the main OLT, and the source MAC address is the NAC address of the line card board of the main OLT; The process of the standby OLT confirming the ONU that needs to communicate according to the active-standby switching information includes: after the standby OLT parses the active-standby switching information, all ONUs that communicate with the line card board of the active OLT are determined as ONUs that need to communicate according to the source MAC address, and the standby OLT transmits data to all ONUs that need to communicate through the line card board.

5. The communication method of the vehicle-mounted passive optical network as claimed in claim 2, characterized in that: The master-slave switching channel is a layer 2 data channel between the main control board and the line card board, and adopts a data link layer private protocol.

6. The communication method of the vehicle-mounted passive optical network according to any one of claims 1 to 5, characterized in that: The method also includes the following steps: after the main OLT is normal, it sends its own status information to the control end; the control end controls the backup OLT to switch to the main OLT.

7. The communication method of the vehicle-mounted passive optical network according to any one of claims 1 to 5, characterized in that: The method further comprises the following steps: the active OLT synchronizes the communication information with the ONU to all the standby OLTs.

8. The communication method of the vehicle-mounted passive optical network according to any one of claims 1 to 5, characterized in that: The process of establishing a communication relationship between the ONU and the standby OLT includes: registering the ONU on the PON interface of the OLT.

9. A vehicle-mounted passive optical network communication system, characterized in that: The system comprises the active OLT and the standby OLT as claimed in any one of claims 1 to 8.

10. The vehicle-mounted passive optical network communication system as claimed in claim 9, characterized in that: The OLT includes a main control board and a line card board, the main control board includes a service data exchange module, and the line card board includes a control module; the communication channel between the service data exchange module and the control module includes the active-standby switching channel; The control module is used to: send active / standby switching information to the service data exchange module through the active / standby switching channel when the OLT is abnormal; and transmit data to the ONU that needs to communicate confirmed by the service data module; The service data exchange module is used to: transmit and receive active / standby switching information; confirm the ONU that needs to communicate based on the received active / standby switching information and inform the control module; and report the OLT's own status.

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