Optical network unit and registration method thereof

Abstract

The invention discloses an optical network unit (ONU) and a registration method thereof, and the registration method comprises the following steps: in a standby state, judging whether network parameter setting information broadcasted by an optical line terminal (OLT) is received or not; in response to judging that the network parameter setting information is received, entering a serial number state, and starting timing to generate timing time; in the serial number state, receiving at least one piece of serial number requirement information from the OLT; in the serial number state, when the timing time does not exceed the exploration time and when the serial number requirement information is received each time, a serial number response message is sent out, whether the identification code distribution information is received or not is judged, and the exploration time is not smaller than the time interval of the ONU receiving the serial number requirement information for at least two times; and when the timing time does not exceed the exploration time, responding to the judgment that the identification code distribution information is received, and entering a distance measurement state.

Description

Technical Field

[0001] The present invention relates to a network device and method, and in particular to an optical fiber network unit and a registration method thereof. Background Art

[0002] A passive optical network (PON) uses optical fiber to provide network services from a central office (CO) to multiple customers. The CO is equipped with an optical line termination (OLT), while the customer premises are equipped with an optical network unit (ONU).

[0003] To allow an ONU to join the PON, the OLT broadcasts a serial number grant message to any ONU that has not yet been assigned an ONU identification code. Any ONU in the serial number state can respond to the serial number grant message with a Physical Layer Operations and Maintenance (PLOAM) message, announcing its presence in the optical network system.

[0004] If the OLT successfully receives the serial ONU PLOAM information, the OLT sends a PLOAM message directly assigning the ONU-ID to the newly added ONU. After receiving the ONU-ID, the ONU continues the startup procedure.

[0005] However, when multiple ONUs respond simultaneously to the Sequence Number Grant message, the OLT may fail to receive the Sequence Number ONU PLOAM due to conflicting responses, causing the ONU startup to fail. Traditional ONUs that fail to boot up must return to the initial or standby state before entering the Sequence Number state and waiting for the next Sequence Number Grant message, which takes longer to complete.

[0006] Therefore, how to reduce the time required for the ONU startup procedure to improve the registration success rate and overcome the above-mentioned defects has become one of the important issues that need to be solved. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an optical network unit (ONU) and a registration method thereof to address the deficiencies of the prior art, thereby reducing the time required for the ONU to complete a startup procedure.

[0008] To address the aforementioned technical issues, one of the technical solutions employed by the present invention is to provide an ONU registration method, wherein the ONU is communicatively connected to an optical line termination (OLT). The ONU registration method includes: in a standby state, determining whether network parameter setting information broadcasted from the OLT is received; in response to determining that the network parameter setting information is received, entering a sequence state and starting a timer to generate a timer; in the sequence state, receiving at least one sequence request message from the OLT; in the sequence state, if the timer time does not exceed a discovery time, each time a sequence request message is received, issuing a sequence response message and determining whether identification code allocation information is received, wherein the discovery time is not less than the time interval between the ONU receiving at least two sequence request messages; and in response to determining that the identification code allocation information is received, if the timer time does not exceed the discovery time, entering a ranging state.

[0009] To address the aforementioned technical issues, another technical solution employed by the present invention is to provide an ONU that is communicatively connected to an OLT. The ONU includes an ONU media access control (MAC) circuit and a discovery time generation circuit. The ONU MAC circuit is configured to perform the following steps: in a standby state, determining whether network parameter setting information broadcast by the OLT has been received; in response to determining that the network parameter setting information has been received, entering a sequence state and starting a timer to generate a timer; in the sequence state, receiving at least one sequence request message from the OLT; in the sequence state, if the timer time does not exceed the discovery time, sending a sequence response message to the OLT each time a sequence request message is received, and determining whether identification code allocation information has been received, wherein the discovery time is not less than the time interval between the ONU receiving at least two sequence request messages; and in response to determining that the identification code allocation information has been received, if the timer time does not exceed the discovery time, entering a ranging state. The discovery time generation circuit is connected to the ONU MAC circuit, generates a discovery time, and provides it to the ONU MAC circuit.

[0010] One of the beneficial effects of the present invention is that the ONU and registration method provided by the present invention can dynamically adjust the exploration time in a specific state based on the time characteristics of the serial number authorization information, thereby increasing the probability of successful ONU registration and reducing the time required for the ONU to complete the startup procedure.

[0011] Furthermore, in the ONU and registration method provided by the present invention, by evaluating the time characteristics of the sequence request information, the time the ONU stays in the sequence state can be extended, allowing the ONU to use this time to generate sequence response messages multiple times in response to the sequence request information without waiting for the time wasted in resetting to the initial state and the standby state. Furthermore, the ONU can be adapted to OLTs of different suppliers or network providers.

[0012] To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and illustration and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FIG. 1 is a functional block diagram of a passive optical network (PON) system according to an embodiment of the present invention.

[0014] Figure 2 FIG. 1 is a timing diagram of signals and states of the OLT and ONU in a PON system according to an embodiment of the present invention.

[0015] Figure 3 for Figure 1 Detailed block diagram of the PON system.

[0016] Figure 4 The figure is a flow chart of a registration method for a PON system according to the present invention.

[0017] Figure 5 FIG. 1 is another signal and status sequence diagram of the OLT and ONU in the PON system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following is an explanation of the implementation methods of the "fiber optic network unit and registration method thereof" disclosed in the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following embodiments will further explain the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention. In addition, the term "or" used in this article may include any one or more combinations of the associated listed items depending on the actual situation.

[0019] Figure 1FIG1 is a functional block diagram of a passive optical network (PON) system 1 according to an embodiment of the present invention. Figure 1 As shown, a PON system 1 is provided, including an optical line termination (OLT) 10, an optical splitter 12 and a plurality of optical network units (ONUs) 14 provided by the present invention.

[0020] In a PON system 1, the OLT 10 is a key device located, for example, at a telecommunications company's network switching center. Its primary functions include data aggregation, optical signal generation, and control management. The OLT 10 collects data from the core network, converts these data signals into optical signals, and transmits them via optical fiber to the various ONUs 14. Furthermore, the OLT 10 manages and distributes signals to each ONU 14, including traffic management, authorization, and error detection, to ensure efficient operation of the entire optical fiber network.

[0021] Specifically, the OLT 10 performs signal conversion, traffic scheduling, control management, and protocol processing. In its signal conversion function, the OLT 10 converts electrical signals into optical signals for transmission via optical fiber. In its traffic scheduling function, the OLT 10 allocates upstream and downstream bandwidth to ensure fair competition among different ONUs 14. In its control management function, the OLT 10 manages the entire PON network, including registration, configuration, and maintenance of the ONUs 14. In its protocol processing function, the OLT 10 handles the encapsulation and decapsulation of PON protocols (such as GPON and EPON).

[0022] The optical splitter 12 is a passive optical component that splits a single optical fiber into multiple optical fibers in the PON system 1. It is used to distribute the optical signal emitted by the OLT 10 to multiple ONUs 14, achieving one-to-many optical fiber transmission. In some embodiments, the optical splitter 12 may be, for example, a planar lightwave circuit (PLC) optical splitter or a fusion-type optical splitter. The PLC optical splitter is based on planar lightwave circuit technology and has advantages such as high performance and low loss. The fusion-type optical splitter fuses multiple optical fibers together and is relatively low in cost. In the PON system 1, in addition to being able to communicate with the OLT 10 through the optical splitter 12, the ONUs 14 can also communicate directly with the OLT 10 in some embodiments.

[0023] Furthermore, the ONUs 14 provided by the present invention can be flexibly distributed across different geographic locations. Each ONU 14 can be installed at a customer premises, such as a home or office. The ONUs 14 receive optical signals from the optical splitter and convert them into electrical signals that can be used by the customer premises. These electrical signals can then be connected to the customer's terminal devices, such as computers and routers, via various interfaces (e.g., an RJ45 Ethernet interface). Furthermore, the ONUs are responsible for signal amplification and decoding, ensuring a stable, high-quality data connection for the customer.

[0024] In PON system 1, high-bandwidth optical fibers connect OLT 10 and ONU 14, providing low-latency, high-speed data transmission. These fibers support long-distance data transmission, making optical fiber networks well-suited for high-speed transmission of large amounts of data.

[0025] Please refer to Figure 2 and Figure 3 , Figure 2 This is a timing diagram of signals and states of the OLT and ONU in a PON system according to an embodiment of the present invention. Figure 3 for Figure 1 Detailed block diagram of the PON system 1. It should be noted that the PON system 1 of the present invention is applicable to Sections 7 to 10 of the ITU-T G.983 series: Transmission Systems and Media, Digital Systems and Networks (ITU-T G.983), Sections C.6, C.8, C.10 to C.12 of ITU-T G.9807.1, and Sections 6, 8, 10, 11, and 12 of ITU-T G.9804.2. Part of the PON system 1 follows the architecture of the aforementioned standards, and therefore, only a detailed description thereof will be provided in the embodiments of the present invention.

[0026] When the ONU is operating in different states—the Initialization State, Standby State, Serial Number State, Ranging State, and Operational State—it interacts with the OLT in different ways. In the Initialization State, the ONU has just been powered on and is starting up. At this point, the ONU establishes a preliminary connection with the OLT and performs a self-test to confirm that its internal modules are operating normally.

[0027] In the standby state, the ONU waits for the global network parameters provided by the OLT. Once the Upstream_Overhead information provided by the OLT is received, the ONU will configure itself according to these network parameters (e.g., delimiter value, power level mode, and pre-allocated delay) and enter the sequence state.

[0028] When the ONU enters the serial number state, it will exchange information with the OLT many times. First, the OLT will continue to broadcast periodic serial number request messages (serial number request message) S1 to each ONU on the optical fiber line. The ONU will respond with a serial number response message (serial number response message) S2 to let the OLT know its own existence and confirm the authorization status. After the ONU responds, it waits for the OLT 10 to assign a unique ONU-ID. This ONU-ID can be assigned by the OLT 10 by sending an identification code assignment message (for example, Assign_ONU-ID information) S3. When the ONU receives the Assign_ONU-ID information, it enters the ranging state. However, if Figure 1 As shown, the sequence response messages S2 from different ONUs may collide, causing the OLT 10 to be unable to process them in time and unable to properly allocate ONU-IDs to some of the ONUs 14 that have transmitted the sequence response messages S2.

[0029] In the ranging state, the OLT 10 and ONU 14 perform synchronous ranging to determine the physical distance between them. This is accomplished by sending specific ranging signals. The OLT 10 sends ranging commands to the ONU 14, which then responds to these signals. Based on the signal's transmission and return time, the OLT 10 can calculate the distance to the ONU 14. This helps adjust signal transmission timing and ensures accurate data transmission within the network.

[0030] More specifically, upstream transmissions from different ONUs 14 must be synchronized with upstream gigabit PON transmission convergence (GTC) frame boundaries. To ensure that the ONUs 14 appear to be at equal distances from the OLT 10, each ONU 14 must have an equalized delay. This equalized delay is measured when the ONU 14 is in the ranging state. Once the ONU 14 receives the Ranging_Time message, it enters the operational state.

[0031] In the operational state, the interaction between the ONU 14 and the OLT 10 enters the normal data transmission phase. During this phase, the ONU 14 receives and forwards data from the OLT 10, while also transmitting client data back to the OLT 10. This includes both upstream and downstream data flows, ensuring the normal operation of the fiber optic network service. In this state, the ONU 14 and OLT 10 continuously monitor the network status, perform traffic management, and detect errors to ensure efficient and stable network operation.

[0032] Figure 4 This is a flow chart of the ONU registration method of the present invention. Figure 3 、 Figure 4 The registration method for ONU of the present invention is described, and Figure 3 Only the necessary components for participating in the registration method are shown, and the present invention is not limited thereto. For example, each ONU 14 may include a discovery time generation circuit 140 and an ONU media access control (MAC) circuit 142. The ONU MAC circuit 142 is further connected to the OLT-PON MAC layer 100 of the OLT 10. The ONU MAC circuit 142 and the discovery time generation circuit 140 may include, for example, a processor or logic circuitry capable of implementing the functions of the ONU MAC circuit 142 and the discovery time generation circuit 140.

[0033] like Figure 4 As shown, the present invention provides an ONU registration method, which includes the following steps: Figure 1 、 3 After the communication connection is established, each ONU 14 is configured to perform the following steps (e.g., via the ONU MAC circuit 142):

[0034] Step S10: In the standby state, determine whether the network parameter setting information broadcast by the OLT is received. As mentioned above, the network parameter setting information S0 may be, for example, the Upstream_Overhead information provided by the OLT as mentioned in the standard.

[0035] In response to determining that the ONU has received network parameter setting information S0 (e.g., Upstream_Overhead information), the registration method proceeds to step S11: configuring the ONU according to the multiple network parameters in the network parameter setting information, entering a sequence state, and simultaneously starting a timer to generate a timed duration. If the network parameter setting information S0 is not received in step S10, step S10 is repeated.

[0036] It should also be noted that the OLT 10 periodically broadcasts the sequence number request message S1, thereby enabling the OLT 10 to detect new or missing ONUs on the optical fiber line and assign an ONU identification code (ONU-ID) to each newly appearing ONU.

[0037] Step S12: Obtain an exploration time.

[0038] For example, the exploration time can be derived based on the time signature of the sequence request message S1. In this embodiment, in response to an ONU receiving at least one sequence request message S1, the exploration time in the sequence state is set based on the time signature of the sequence request message. In this step, when the ONU MAC circuit 142 receives the sequence request message S1, it analyzes the time signature of the sequence request message S1 to obtain the time signature of the sequence request message S1. This time signature can be used to determine the total time the ONU remains in the sequence state, i.e., to set the aforementioned exploration time. After the exploration time is generated, the exploration time generation circuit 140 provides it to the ONU MAC circuit 142.

[0039] For example, the time characteristics may include the duration of each sequence request message S1 and / or the transmission period of the sequence request message S1. It should be noted that the exploration time is not less than twice the transmission period of the sequence request message, meaning that the exploration time allows for the reception of at least two sequence request messages. In some embodiments, the exploration time is set in accordance with the time characteristics of the sequence request message. For example, the exploration time may be within a exploration time range defined by a maximum exploration time and a minimum exploration time. For example, the existing Gigabit / 10Gigabit passive optical networks (G / XG-PON) transmission convergence layer specification defines a serial number acquisition and ranging timer (TO1 timer) for the sequence state and ranging state. This timer is used to terminate unsuccessful startup attempts by limiting the total time an ONU remains in the sequence state and ranging state. In the above specification, the minimum exploration time must be greater than the preset time limit, thereby extending the time the ONU 14 stays in the sequence state, so that the ONU 14 can use this period to generate sequence response messages S2 multiple times to respond to the sequence request message S1.

[0040] In some embodiments, the exploration time generating circuit 140 may include a counter for counting the number of times the sequence number request message S1 is received, and when the count reaches a predetermined number (at least two), an interrupt is issued to the ONU MAC circuit 142 to terminate the exploration time.

[0041] It is worth noting that since OLTs 10 from different vendors or network providers may employ different dynamic bandwidth allocation algorithms and characteristics regarding the intervals used to discover ONUs and sequence authorization information (i.e., sequence request information S1), the present invention enables the ONU 14 to adapt to OLTs 10 from different vendors or network providers by evaluating the timing characteristics of sequence request information S1.

[0042] Furthermore, in step S12, the length of the exploration time can be determined in various ways. For example, the user can experimentally determine the number of sequence response messages S2 that the ONU 14 should be allowed to transmit in response to a predetermined number of sequence request messages S1 in the current PON system 1. This allows the user to determine an experimental time interval and use it to set the length of the exploration time. In other words, the exploration time is set as a fixed time interval rather than based on the time characteristics of the sequence request messages S1. The predetermined number is a positive integer not less than 2. In one embodiment, the predetermined number is preset to 5.

[0043] Similarly, the maximum exploration time can also be determined through experiments to have an appropriate upper limit, so as to prevent the ONU 14 from waiting for too long in the event of a system anomaly and failing to reset to the initial state or standby state in real time.

[0044] Step S13-1: When the timing time does not exceed the exploration time, each time a sequence number request message is received, a sequence number response message is sent to the OLT, and then the process proceeds to step S13-2: determining whether the identification code allocation information is received.

[0045] Therefore, you can refer to Figure 5 , Figure 5 FIG1 is another signal and status sequence diagram of the OLT and ONU in the PON system 1 according to an embodiment of the present invention. Figure 5 In the example, the preset number can be 5. In other words, before the timing time exceeds the set exploration time, the OLT 10 can send a sequence number response message S2 up to five times when receiving the sequence number request message, until the identification code allocation message S3 is received, or until the timing time exceeds the exploration time. Figure 5 As shown, after the first four sequence number response messages S2 were sent to OLT 10, OLT 10 did not send back identification code allocation information S3. This indicates that there may have been a collision with sequence number response messages S2 from other ONUs 14, resulting in OLT 10 failing to allocate an ONU ID in real time. It was not until the fifth sequence number response message S2 was sent to OLT 10 that OLT 10 received identification code allocation information S3 from OLT 10.

[0046] In response to receiving the identification code allocation information S3 when it is determined that the timing time does not exceed the exploration time, the registration method executes step S14: entering the ranging state.

[0047] In response to determining that the identification code allocation information S3 is not received when the timing time does not exceed the exploration time, the registration method executes step S15: configuring the ONU to enter the initial state and enter the standby state again, and returns to step S10.

[0048] It should be noted that the ONU MAC circuit 142 can be used to receive and send various physical layer operations and maintenance messages (PLOAM), including the aforementioned network parameter setting message S0, sequence number request message S1, sequence number response message S2 and identification code allocation message S3.

[0049] Here, after the ranging state ends, the ONU 14 is successfully registered in the OLT 10 and enters the operating state, so that the interaction between the ONU and the OLT enters the normal data transmission stage.

[0050] [Beneficial Effects of Embodiments]

[0051] One of the benefits of the present invention is that the ONU and registration method provided by the present invention can adjust the exploration time in a specific state according to the time characteristics of the serial number authorization information, thereby increasing the probability of successful ONU registration and reducing the time required for the ONU to complete the startup procedure.

[0052] The contents disclosed above are only preferred feasible embodiments of the present invention and do not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the description and drawings of the present invention are included in the scope of the patent application of the present invention.

[0053]

Explanation of symbols

[0054] 1: Passive fiber optic network system

[0055] 10: Fiber optic line terminal

[0056] 100:OLT-PON media access control) layer

[0057] 12: Optical Splitter

[0058] 14: Optical Network Unit

[0059] 140:Exploring the Time Generating Circuit

[0060] 142:ONU media access control circuit

[0061] S0: Network parameter setting information

[0062] S1: Serial number request information

[0063] S2: Sequence number response message

[0064] S3: Identification code allocation information

[0065] S10, S11, S12, S13-1, S13-2, S14, S15: Steps

Claims

1. A method for registering an optical network unit (ONU), wherein the ONU is communicatively connected to an optical line terminal (OLT), the method comprising the following steps: In a standby state, determining whether a network parameter setting information broadcasted from the OLT is received; In response to determining that the network parameter setting information is received, entering a sequence state, and starting timing to generate a timing time; In the sequence number state, receiving at least one sequence number request message from the OLT; In the sequence number state, when the timer time does not exceed a search time, each time the sequence number request information is received, a sequence number response message is sent to the OLT, and it is determined whether an identification code allocation information is received, wherein, The exploration time is not less than the time interval between the ONU receiving the at least two sequence number request messages; and When the timing time does not exceed the exploration time, and in response to determining that the identification code allocation information is received, a ranging state is entered.

2. The ONU registration method according to claim 1, wherein: The setting of the exploration time is related to a time feature of the at least one sequence number request information.

3. The ONU registration method according to claim 1, wherein: The OLT periodically broadcasts the at least one sequence number request information.

4. The ONU registration method according to claim 1, wherein: The exploration time is within an exploration time range defined by a maximum exploration time and a minimum exploration time, and the minimum exploration time is at least greater than a preset time limit of a serial number acquisition and ranging timer in the Gigabit / 10Gigabit passive optical networks (G / XG-PON) transmission convergence layer specification.

5. The ONU registration method according to claim 1, wherein: The time characteristic includes a duration of each of the sequence request messages and the transmission period.

6. The ONU registration method according to claim 5, wherein: The exploration time is greater than or equal to the transmission period plus the duration multiplied by a predetermined number.

7. The ONU registration method according to claim 1, wherein: In response to not receiving the identification code allocation information after the timing time exceeds the exploration time, the ONU enters the standby state again.

8. An optical network unit (ONU) communicatively connected to an optical line terminal (OLT), the ONU comprising: An ONU media access control (MAC) circuit is configured to perform the following steps: In a standby state, determining whether network parameter setting information broadcast by the OLT is received; In response to determining that the network parameter setting information is received, entering a sequence state and starting timing to generate a timing time; In the sequence number state, receiving at least one sequence number request message from the OLT; In the sequence number state, when the timer time does not exceed a discovery time, each time the sequence number request message is received, a sequence number response message is sent to the OLT, and a determination is made as to whether an identification code allocation message is received, wherein the discovery time is not less than the time interval between the ONU receiving at least two sequence number request messages; and When the timing time does not exceed the exploration time, in response to determining that the identification code allocation information is received, entering a ranging state; and A discovery time generating circuit is connected to the ONU MAC circuit, generates the discovery time and provides it to the ONU MAC circuit.

9. The ONU according to claim 8, wherein: The exploration time generating circuit sets the exploration time according to a time characteristic of the at least one sequence number request information.

10. The ONU according to claim 9, wherein: The time characteristic includes a duration of each of the sequence request messages and the transmission period.

11. The ONU according to claim 10, wherein: The exploration time is greater than or equal to the transmission period plus the duration multiplied by a predetermined number, wherein the predetermined number is a positive integer not less than 2.

12. The ONU according to claim 8, wherein: The ONU MAC circuit also enters an initial state in response to not receiving the identification code allocation information after the timing time exceeds the exploration time, and the ONU enters the standby state again.

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