Power distribution network automatic communication data packet forwarding method based on improved EPON (Ethernet Passive Optical Network) technology

Abstract

The invention discloses a power distribution network automatic communication data packet forwarding method based on an improved EPON technology, and the method comprises the steps: 1, classifying and scheduling data packets, and determining the transmission sequence of data packets with different priorities through weighted polling scheduling; step 2, an optical line terminal (OLT) receives the data packet and records sending address information and forwarding rules of the data packet; step 3, the ONU extracts a target address and a forwarding rule, and obtains a position and a connection state to calculate an optimal data transmission path; and step 4, monitoring and managing the operation state, and ensuring the forwarding stability and reliability of the data packet. According to the method for realizing artificial intelligence by improving the EPON technology, automatic communication data packet forwarding is realized, and the transmission efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of distribution network communication, and more specifically to a distribution network automation communication data packet forwarding method based on an improved EPON technology. Background Art

[0002] Distribution network automation communication is the process of applying communication technology to achieve automated management and control in distribution networks, improving the reliability, efficiency and intelligence level of power grid operation. EPON is an Ethernet-based passive optical network technology that uses optical fiber communication to provide high-bandwidth connections. It is mainly composed of optical line terminals, optical network units and passive optical splitters. It provides pre-megabit bandwidth, supports two-way communication, quickly responds to remote control commands and transmits collected data in real time, and meets the large data volume and high real-time communication needs of distribution networks.

[0003] In the prior art, there are also related technical studies on this technology, among which patent number CN 114025259A discloses a power distribution networking system and communication method based on EPON technology. This technology is through a power distribution master station, a substation and a power distribution terminal, the communication master station is configured at the power distribution master station, and the optical line terminal is configured at the substation; the optical network unit on the user side is configured at the power distribution terminal, and the communication master station and the optical line terminal are connected through SDH optical transmission equipment to realize data transmission, but this technology is not designed for data forwarding. The EPON system forwards data packets and needs to transmit the data packets from the optical network unit on the user side uplink to the optical line terminal. After receiving and processing and parsing, the next destination of the data packet is determined according to the destination address or other relevant information of the data packet, and the data packet is forwarded to the destination optical network unit through the downlink. It takes a long time to coordinate and manage data between user devices through the optical line terminal, and there are differences in the time for the user side to receive the same data packet. It is urgent to improve the distribution network automation communication of EPON technology to forward data packets and improve transmission efficiency. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned technology, the present invention discloses a distribution network automation communication data packet forwarding method based on an improved EPON technology. By setting a two-level optical network unit, the optimal data transmission path is calculated by obtaining the position and connection status through the link state protocol, and the forwarding position method is determined to realize the distribution network automation communication data packet forwarding, which greatly improves the transmission efficiency and has a simple structure.

[0005] A method for forwarding data packets of distribution network automation communication based on improved EPON technology, comprising the following steps:

[0006] Step 1: Data packet classification and scheduling: According to the communication requirements of distribution network automation, data packets are classified into different priorities and the sending order of data packets of different priorities is determined through weighted round-robin scheduling;

[0007] In this step, data packet classification and scheduling is a key link in the distribution network automation communication. The distribution network automation system needs to transmit a large amount of monitoring data, control commands and business data in real time, and the transmission of these data packets needs to meet different real-time and reliability requirements. Therefore, it is an important means to improve the efficiency and reliability of distribution network automation communication to reasonably classify and schedule data packets to ensure that data packets can be processed in time according to their importance and urgency.

[0008] Packet classification is usually based on factors such as packet content, purpose, urgency, etc. For example, packets can be classified into the following categories:

[0009] Monitoring data packet: including real-time status data of the distribution network, equipment operation data, etc.

[0010] Control command data packet: including switch control commands, adjustment commands, etc.

[0011] Business data packet: including user information, billing data, etc.

[0012] Different categories of data packets may have different priorities. For example, control command data packets usually have the highest priority because they are related to the safe operation and stability of the distribution network.

[0013] Weighted round-robin scheduling is a commonly used scheduling algorithm that can determine the sending order according to the priority of the data packet. The basic idea of ​​the weighted round-robin scheduling algorithm is that each data packet is assigned a weight, and the weight reflects the priority of the data packet. The algorithm will poll and send data packets according to the weight of the data packet, and the data packets with high weights will be sent first. When implementing weighted round-robin scheduling, the system will determine the sending order according to the weight of each data packet, so as to ensure that high-priority data packets can be transmitted in time. At the same time, the weighted round-robin scheduling algorithm can also adjust the weight of the data packet according to the actual situation to adapt to the dynamic changes in the distribution network automation communication. In summary, through data packet classification and weighted round-robin scheduling, the distribution network automation communication system can effectively manage data packets of different priorities and ensure the real-time transmission of key data packets, thereby improving the operating efficiency and reliability of the entire system.

[0014] Step 2: The optical line terminal OLT receives the data packet and records the data packet sending address information and forwarding rules; in the distribution network automation communication, the optical line terminal (OLT) plays an important role. OLT is a device located in the distribution network communication network, which is mainly used to receive data packets from various monitoring points and control points of the distribution network, and forward these data packets to the correct destination according to the preset forwarding rules. OLT receives data packets from various sensors, controllers and other terminal devices in the distribution network through optical fiber connection. These data packets may contain information about the power grid status, equipment operation status, control commands, etc. When OLT receives a data packet, it records the sending address information of the data packet, which usually includes the identifier, IP address or port number of the sending device. This helps OLT to effectively forward data packets later. According to the communication requirements of the distribution network automation system, OLT presets a series of forwarding rules. These rules determine how OLT should handle when it receives a data packet, including whether it needs to be forwarded, to which destination it is forwarded, whether it needs to be processed first, etc. When OLT receives a data packet, it will process it according to the recorded sending address information and the preset forwarding rules. If the data packet needs to be forwarded, OLT will look up the corresponding forwarding rules and send the data packet to the specified destination. These destinations may include other OLTs, other devices in the distribution network, or a centralized monitoring center. The OLT also monitors the status of the network to ensure the correct transmission of data packets. When necessary, the OLT will take maintenance measures, such as rerouting data packets, to respond to failures or congestion in the network. The OLT also typically interacts with upper-layer systems (such as a centralized monitoring center) to provide network status information, receive control commands, and adjust forwarding rules based on these commands.

[0015] Step 3, the optical network unit ONU parses the data packet header information, extracts the target address and forwarding rules, queries the local flow table to forward the data packet to other optical network units ONU or terminal devices or forwards it upstream;

[0016] In the distribution network automation communication, the optical network unit (ONU) is the terminal device in the optical fiber communication network, which is usually installed at various monitoring points and control points of the distribution network. The main function of the ONU is to receive data packets from the optical line terminal (OLT), parse the header information of the data packet, and perform corresponding data packet processing and forwarding according to this information. The ONU receives data packets sent from the OLT, which may contain information about the power grid status, equipment operation status, control commands, etc. The ONU parses the header information of the data packet, which usually contains key information such as the destination address, source address, protocol type, priority, etc. This information is crucial for the ONU to correctly process and forward data packets. The ONU extracts the destination address based on the header information and determines the destination to which the data packet needs to be forwarded. At the same time, the ONU will query the local flow table (Flow Table) to determine how to process the data packet according to the preset forwarding rules. The ONU queries the local flow table to find the flow table entry that matches the received data packet. The flow table entry contains forwarding rules, such as the destination, forwarding port, queue, and other information of the data packet. According to the instructions of the flow table entry, the ONU decides to forward the data packet to other ONUs, terminal devices, or forward it upstream back to the OLT. The ONU forwards the data packet to the corresponding destination according to the forwarding rules in the flow table. If the destination address is to other ONUs, the ONU will send the data packet to the destination ONU through optical fiber; if the destination address is to a terminal device, the ONU will send the data packet to the terminal device through Ethernet or other local connections; if upstream forwarding is required, the ONU will send the data packet back to the OLT or other upper-level nodes.

[0017] Step 4: Monitor and manage the operation status, ensure the stability and reliability of data packet forwarding, synchronize the optical line terminal OLT flow table with the optical network unit flow table, and keep the latest forwarding rules. In the distribution network automation communication, it is very important to ensure the stability and reliability of data packet forwarding. In order to achieve this goal, it is necessary to monitor and manage the operation status of the network and keep the flow table between the optical line terminal (OLT) and the optical network unit (ONU) synchronized. The following are the specific methods and steps to achieve this goal:

[0018] 1. Operation status monitoring:

[0019] Real-time monitoring of the operating status of OLT and ONU, including hardware status, software status, network connection status, etc. Monitor the forwarding efficiency and latency of data packets to ensure that data packets can reach the destination on time. Detect faults and abnormal conditions in the network, such as fiber breakage, equipment overload, etc.

[0020] 2. Packet forwarding stability guarantee:

[0021] Implement failover and backup mechanisms to automatically switch to the backup path when the primary path fails. Use Quality of Service (QoS) policies to ensure that packets of different priorities can be forwarded according to predetermined rules. Implement traffic shaping and congestion control policies to prevent performance degradation caused by network congestion.

[0022] 3. Flow table synchronization:

[0023] The flow table between OLT and ONU needs to be synchronized regularly or when configuration changes occur. The flow table is updated and synchronized through dedicated synchronization protocols or management interfaces, such as NETCONF and RESTCONF. During the synchronization process, ensure that the new forwarding rules can be applied to the ONU in a timely manner.

[0024] 4. Forwarding rules update:

[0025] When the topology or service requirements of the distribution network change, the flow tables of OLT and ONU need to be updated. When updating the flow tables, it is necessary to minimize the impact on network performance and ensure a smooth transition of the update process.

[0026] 5. Configuration Management:

[0027] Manage the configuration of OLT and ONU to ensure that all devices are configured according to unified configuration standards. Use configuration management tools such as TL1, SNMP, CLI, etc. to remotely configure and manage devices.

[0028] 6.Performance optimization:

[0029] Regularly evaluate and optimize network performance, including adjusting forwarding rules, optimizing routing paths, etc. Adjust QoS policies and traffic management parameters according to the actual situation of the network.

[0030] 7. Safety management:

[0031] Implement network security measures such as access control, encryption, and authentication to protect the security of communication data. Perform permission management on network devices to ensure that only authorized users can modify network configurations. Through the above methods, the stability and reliability of data packet forwarding in distribution network automation communication can be ensured, while keeping the OLT and ONU flow tables synchronized to adapt to dynamic changes in the network. This helps to improve the automation level of the distribution network and ensure the reliability and security of power supply.

[0032] Furthermore, the weighted round-robin scheduling priority calculation formula is as follows:

[0033]

[0034] In formula (1), w1 represents the weight of the primary optical network unit ONU receiving end, w2 represents the weight of the secondary optical unit network ONU receiving end, and r 1,i Indicates T i The first-level receiving end level of the data packet, r 2,i Indicates the secondary receiving end level, b i represents the bandwidth requirement of the ith data packet, and B represents the available bandwidth; represents the weight function of historical packet loss rate, ω i Indicates the packet loss rate. Using the SNMP protocol, the optical line terminal OLT regularly queries and collects the packet loss rate of the optical network unit ONU device, and adjusts the transmission priority by forwarding data packets to the device with a larger packet loss rate; the OLT calculates the priority of each ONU according to the above formula, and determines the forwarding order of the data packets based on the calculation result. If an ONU has a higher packet loss rate, its priority may be reduced, resulting in it obtaining less bandwidth, which helps to improve the overall performance and reliability of the network.

[0035] The historical packet loss rate weight function is as follows:

[0036]

[0037] In formula (2), P represents the detection packet loss rate, P min Indicates setting the minimum threshold of packet loss rate, P max represents the highest threshold of packet loss rate, k1 represents the weight influence coefficient to adjust the scheduling priority through historical data; φ(D j ) represents the queue length weight coefficient, D j Indicates the amount of data to be transmitted, through φ(D j )=ln(D j +1)+β logarithmic function maps the queue length weight to ensure that tasks with large data transmission volume receive appropriate priority, and β represents the offset;

[0038] In a further specific embodiment, the historical packet loss rate weight function is usually implemented in network devices, including optical line terminals (OLTs), optical network units (ONUs), and other network nodes. The hardware environment for implementing this function may include the following aspects:

[0039] 1. Processor (CPU): The processor is the core component that performs calculations and processing tasks. For the calculation of the weight function, a processor with sufficient computing power is required.

[0040] 2. Memory (RAM): Memory is used to store current data packets, historical data packets, and temporary data during the calculation process. Sufficient memory capacity can ensure that the calculation of the weight function will not be affected by insufficient data.

[0041] 3. Memory (ROM / Flash): The memory is used to store the operating system, firmware, configuration files, and algorithm code of the weight function.

[0042] 4. Network interface:

[0043] The network interface is used to receive and send data packets, including Ethernet, fiber optic interface, etc.

[0044] 5. Timer / Counter:

[0045] The timer / counter is used to record time and is very important for calculating the historical packet loss rate weight function.

[0046] 6.SNMP interface:

[0047] The SNMP (Simple Network Management Protocol) interface is used to communicate with ONU devices and collect network performance indicators such as packet loss rate.

[0048] 7. Digital Signal Processor (DSP):

[0049] For tasks that require complex calculations, such as statistics and probability calculations, it may be necessary to use a DSP to accelerate processing.

[0050] 8. Application-Specific Integrated Circuit (ASIC):

[0051] For high performance and low latency requirements, ASICs may be used to specifically handle network-related tasks, including the calculation of weight functions.

[0052] 9. Power Management Unit (PMU):

[0053] The power management unit ensures that the device can operate stably under different working conditions.

[0054] 10. Temperature sensor and fault detection circuit:

[0055] Used to monitor the operating temperature of equipment and detect faults in a timely manner.

[0056] These hardware components together constitute the hardware environment for implementing the historical packet loss rate weight function. In actual deployment, network equipment manufacturers will integrate these components in their equipment to ensure network performance and reliability. In addition, hardware design also needs to consider scalability and compatibility so that it can adapt to different network scales and future technology upgrades.

[0057] Different ranges of input mappings have appropriate weight factor values, and the weight function formula is as follows:

[0058]

[0059] In formula (3), where r 1,min Indicates the lower limit of the primary optical unit network receiving end in the value range, r 1,max represents the upper limit of the first-level optical unit network receiving end, w 1,min and w 1,max Respectively represent the minimum and maximum values ​​of the weight, the secondary optical unit network receiving end weight w2 calculation formula is the same, the linear transformation ensures that the input value is evenly distributed within the range and maps the corresponding weight factor value, balancing the primary and secondary receiving end levels to the priority p i The impact of

[0060] The calculation of the weight factor relies on a linear transformation to ensure that the input values ​​are evenly distributed within a specified range and mapped to the corresponding weight factor values. This linear transformation method can help balance the impact of the primary and secondary receiver levels on the priority.

[0061] The calculation of the weight factor can follow the following steps:

[0062] In formula (3), the calculation of the weight factor relies on a linear transformation to ensure that the input values ​​are evenly distributed within a specified range and mapped to the corresponding weight factor values. This linear transformation method can help balance the impact of the primary and secondary receiver levels on the priority. Specifically, the calculation of the weight factor can follow the following steps:

[0063] 1. Determine the upper and lower limits of the input range: For the primary ONU receiving end, determine a minimum value (L_{\text{lower limit}}), which represents the lowest receiving performance level. At the same time, determine a maximum value (L_{\text{upper limit}}), which represents the highest receiving performance level.

[0064] 2. Determine the value range of the weight factor:

[0065] 3. Apply the linear transformation formula:

[0066] For each ONU, the receiving end level value (L) is mapped to a weight factor (W) using the following linear transformation formula: [W = \frac{(L L_{\text{lower limit}})}{L_{\text{upper limit}}L_{\text{lower limit}}}\times(W_{\text{maximum}}W_{\text{minimum}})+W_{\text{minimum}}], which converts the receiving end level value into a weight factor between (W_{\text{minimum}}) and (W_{\text{maximum}}).

[0067] 4. Apply the same calculation formula to the secondary ONU receiving end: For the secondary ONU, repeat the above process and use the same linear transformation formula to map the level value (L_2) to the weight factor (W_2).

[0068] In this way, no matter it is the primary or secondary receiver, their level values ​​will be fairly converted into corresponding weights, which will in turn affect the scheduling frequency and resource allocation of data packets.

[0069] In the polling process, each data packet is assigned to a time slot according to its weight factor, and the frequency of the time slot determines the frequency at which the data packet is scheduled. ONUs with higher weight factors will have a higher chance of obtaining resources, but this opportunity is allocated according to predetermined rules and frequencies to ensure fairness and rational use of resources.

[0070] In the polling process, each data packet is assigned to a time slot according to its weight factor, and the frequency of the time slot determines the frequency at which the data packet is scheduled. ONUs with higher weight factors will have a higher chance of obtaining resources, but this opportunity is allocated according to predetermined rules and frequencies to ensure fairness and rational use of resources.

[0071] In the polling process, resources are allocated according to the scheduling frequency of each data packet. The scheduling frequency formula is as follows:

[0072]

[0073] In formula (4), w i represents the weight of the ith packet, b i represents the bandwidth requirement of the ith data packet, represents the sum of all data packet weights, φ(D j ) represents the queue length weight coefficient, p i represents the priority of the weighted round-robin scheduling, represents the weight function of the historical packet loss rate, and λ represents the factor affecting the packet loss rate on the scheduling frequency; the scheduling frequency of each task is adjusted by the weight factor and the bandwidth requirement to determine the sending order of data packets with different priorities.

[0074] During the polling process, the scheduling frequency of data packets is allocated based on the weight factor of each data packet. The scheduling frequency formula mentioned here does not directly provide the specific value of the scheduling, but is used to calculate the weight factor of each data packet, which is then used to determine the number of times the data packet is scheduled during the polling period.

[0075] Assuming we have a polling period \(T\), the scheduling frequency \(f\) of each data packet can be calculated by the following formula:

[0076] \[f=W\times T\]

[0077] Where \(W\) is the weight factor of the packet and \(T\) is the polling period. This formula shows that the scheduling frequency of a packet is a multiple of its weight factor, which ensures that packets with higher weight factors are scheduled more frequently within the polling period.

[0078] In terms of implementation, the hardware environment usually includes the following key components:

[0079] 1. Processor (CPU): used to perform computing tasks, including calculating the weight factor and scheduling frequency of data packets.

[0080] 2. Memory (RAM): used to store data packet information, intermediate results of weight factor calculation, and polling cycle settings.

[0081] 3. Memory (ROM / Flash): used to store the operating system, firmware, and code for the weight factor calculation algorithm.

[0082] 4. Network interface: used to receive and send data packets and communicate with ONU devices.

[0083] 5. Timer / Counter: used for precise timing to ensure the accuracy of the polling cycle.

[0084] 6. DSP or ASIC: For tasks that require high-performance computing, a DSP or ASIC may be used to accelerate processing.

[0085] 7. Poll Scheduler: This is a software component responsible for scheduling packets based on the weight factor and polling period.

[0086] 8. Fault detection and processing circuit: used to monitor the system health and take appropriate measures when a fault occurs.

[0087] In actual applications, network equipment manufacturers will integrate these components in their equipment to ensure network performance and reliability. Hardware design also needs to consider scalability and compatibility so that it can adapt to different network sizes and future technology upgrades. In this way, weight factor calculation and polling scheduling can be effectively implemented in the hardware environment, thereby achieving fair scheduling of data packets and efficient allocation of resources.

[0088] Furthermore, the recorded data packet sending address information includes the MAC hardware address, physical port number and logical identifier of the optical network unit ONU, and the formula for allocating the logical identifier is as follows:

[0089] A id =A index ×W+λ bit (5)

[0090] In formula (5), all bits of the bitmap array are initialized to 0, A index Indicates traversing the bitmap array A and finding the first unused identifier position, W indicates the number of bits that the array element can hold, and λ bit Indicates the first 0bit position in the first element; sets the corresponding bit to 1 and returns an identifier, the optical line terminal OLT calls the allocation logical identifier, allocates a unique identifier for the ONU, and sends a confirmation message; the record forwarding rule includes the forwarding action and the sending order rules of the different priority data packets.

[0091] In an optical network unit (ONU), the sending address information of a data packet usually includes the MAC hardware address, physical port number, and logical identifier. This information is used to ensure that the data packet can be accurately sent to the target device. The following is the principle of allocating these address information:

[0092] 1.MAC hardware address:

[0093] A MAC address (Media Access Control address) is a unique hardware address used to identify a network interface card (NIC) in a network. The MAC address of an ONU is usually burned into the hardware by the manufacturer at the factory to ensure that each ONU is unique worldwide. When an ONU joins a network, it reports its MAC address to the upper-level network device (such as OLT) in order to establish communication.

[0094] 2. Physical port number:

[0095] The physical port number refers to the specific physical interface that connects the ONU to the upper-level device (such as OLT). The port number is assigned by the OLT and is used to identify each ONU connected to the OLT. The physical port number is usually configured by the OLT when the ONU is initialized and is fixed in the ONU hardware.

[0096] 3. Logical identifier:

[0097] A logical identifier is an identifier defined by an upper layer protocol or application to distinguish different ONU instances or logical entities in the network. The logical identifier can be calculated based on the ONU's MAC address, port number, or other parameters. Its purpose is to provide a simple way to reference a specific ONU in a multi-ONU environment. The allocation of logical identifiers is usually done by the network management system (NMS) or OLT, and may be accompanied by the ONU registration and configuration process. The working principle of the formula for allocating logical identifiers may involve the following aspects:

[0098] Combined Identifier: Combines the MAC address and physical port number into a unique identifier, for example,

[0099] `MAC_address+Physical_port_number`.

[0100] Hash function: Use a hash function to process the MAC address or port number to generate a logical identifier.

[0101] Database query: In the network management system, the MAC address, port number and logical identifier are associated through database query.

[0102] In actual applications, the allocation formula of logical identifiers will vary according to the specific network architecture and business requirements. It is important to ensure that each ONU has a unique logical identifier so that it can be accurately identified and routed during data packet transmission.

[0103] Furthermore, a Broadcom BCM56150 switching chip is used to enable the primary optical network unit ONU to dynamically learn the network topology information of the secondary optical network unit ONU, and the position and connection status are obtained through the link state protocol to calculate the best data transmission path. The steps for implementing the transmission path are as follows:

[0104] Step 1, initialize the ONU set, set the first-level optical network unit ONU to S, create an ONU set. For each ONU unit in the set v = S, set X dist (v) = 0, which does not match the source ONU setting of infinity, and is formatted as

[0105] In this step, an ONU set is created to store all ONUs participating in the communication. A first-level optical network unit ONU is set. In the ONU set, a first-level ONU is selected as the source ONU, which is marked as S. A first-level ONU generally refers to an ONU directly connected to an upper-level device (such as OLT). Create an ONU set. For each ONU unit in the set, the above operation needs to be performed for each ONU unit in the ONU set. Set variables related to the source ONU S. The above is a part of the data packet forwarding method for distribution network automation communication, which is generally used to determine the transmission path of the data packet from the source ONU S to other ONU_i. This method can help optimize the forwarding of data packets, reduce delays and improve efficiency.

[0106] Step 2: Update the node distance. Select the node with the smallest distance among the unprocessed ONUs, and update the distance of the neighbor node through the smallest ONU node. The update formula is as follows:

[0107]

[0108] In formula (6), X dist (u) represents the currently known shortest path length from the source node ONU to the secondary optical network unit u, u represents the ONU node with the shortest distance in the ONU set, v represents the unprocessed neighbor ONU node, α represents the adjustment coefficient, weighing the delay and load impact, ε delay (u,v) represents the transmission delay from u to v, b(u,v) represents the bandwidth from u to v, δ(u,v) represents the load from u to v, and r represents the load weight coefficient. When the distance from the source ONU to the neighbor ONU node v is greater than Distance, then retain the updated distance and remove the minimum ONU node u from the ONU set, repeat the update until the set is empty to confirm the shortest path and the predecessor node; in the network, each ONU has a distance value, which represents its distance to the source ONU. Unprocessed ONU refers to those ONUs that have not been selected as nodes on the shortest path. By comparing the distance values ​​of all unprocessed ONUs, the ONU with the smallest distance is selected as the current shortest path node. Once the ONU node with the smallest distance is selected, it is necessary to update the distance of its neighboring nodes. It helps to ensure that data packets can be quickly and effectively forwarded along the shortest path, thereby improving the performance and reliability of the entire network.

[0109] Step 3: Obtain a data forwarding address, and determine the forwarding location through a hash function according to the IP address of the terminal device assigned by the optical line terminal OLT. The hash function formula is as follows:

[0110]

[0111] In formula (7), P s represents the IP address of the primary optical network unit ONU, s represents setting the primary optical network unit ONU as the source address unit, P dst Indicates the target IP address, dst indicates the target address unit, %N indicates the modulo budget, and N indicates the total number of secondary ONU units; set the forwarding identifier, the forwarding identifier is 1, and the data packet is forwarded through the IEEE802.1Q VLAN standard according to the obtained location information, and the forwarding identifier is 0, and no forwarding operation is performed.

[0112] Furthermore, a hardware structure of a method for forwarding data packets for distribution network automation communication of an improved EPON technology comprises:

[0113] Optical line terminal OLT, configured with the load output end of the distribution network, is used to receive data packets, record the data packet sending address information and forwarding rules, and set the user end IP address;

[0114] Optical Distribution Network (ODN), used for transmission and distribution of optical signals;

[0115] The primary optical network unit ONU is used to parse the packet header information, extract the destination address, and forward the packet to the secondary optical network unit ONU;

[0116] Secondary optical network unit ONU, used to receive optical transmission network data, convert it into electrical signals and transmit it to user equipment;

[0117] The output end of the optical line terminal OLT is connected to the input end of the optical distribution network ODN, the output end of the optical distribution network ODN is connected to the input end of the primary optical network unit ONU, and the output end of the primary optical network unit ONU is connected to the input end of the secondary optical network unit ONU.

[0118] Positive beneficial effects

[0119] By improving the EPON technology, the priority of the transmission data packet is determined through weighted polling, and a resource allocation strategy is formulated to ensure that high-priority tasks get resources first, thereby improving the overall efficiency and performance of the system, adjusting bandwidth allocation, ensuring fair use of bandwidth resources, and improving data transmission efficiency; by setting up two-level optical network units and obtaining the best transmission path and forwarding position information through the first-level optical network unit, there is no need for data forwarding between optical network units between the uplink data packet and the optical line terminal OLT, thus shortening the transmission time. Only the data packets without detected forwarding identifiers are forwarded to the optical line terminal OLT, and the OLT decides how to transmit the data packets to the target ONU. The transmission efficiency is still significantly improved, thereby improving the communication efficiency of the distribution network automation. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor, among which:

[0121] Figure 1 It is a schematic diagram of the overall architecture of a method for forwarding data packets for distribution network automation communication using an improved EPON technology of the present invention;

[0122] Figure 2 A schematic diagram of the bandwidth allocation principle architecture in a method for forwarding data packets for distribution network automation communication using an improved EPON technology of the present invention;

[0123] Figure 3 A schematic diagram of the principle architecture of obtaining the position and transmission path in a method for forwarding data packets for distribution network automation communication based on an improved EPON technology of the present invention;

[0124] Figure 4 The present invention is a hardware structure diagram of a method for forwarding data packets for distribution network automation communication based on an improved EPON technology. DETAILED DESCRIPTION

[0125] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0126] like Figure 1-Figure 4 As shown, a method for forwarding data packets for distribution network automation communication using an improved EPON technology comprises the following steps:

[0127] Step 1: Data packet classification and scheduling: According to the communication requirements of distribution network automation, data packets are classified into different priorities and the sending order of data packets of different priorities is determined through weighted round-robin scheduling;

[0128] Step 2: The optical line terminal OLT receives the data packet and records the data packet sending address information and forwarding rules;

[0129] Step 3, the optical network unit ONU parses the data packet header information, extracts the target address and forwarding rules, obtains the link state protocol position and connection status to calculate the best data transmission path, and obtains the forwarding optical network unit ONU position information;

[0130] Step 4: Monitor and manage the running status to ensure the stability and reliability of data packet forwarding, synchronize the OLT flow table of the Guangxin Road terminal with the optical network unit flow table, and maintain the latest forwarding rules.

[0131] As a further embodiment of the present invention, the forwarding priority of the data packet collected by the distribution network is confirmed, and the weighted polling scheduling priority calculation formula is as follows:

[0132]

[0133] In formula (1), w1 represents the weight of the primary optical network unit ONU receiving end, w2 represents the weight of the secondary optical unit network ONU receiving end, and r 1,i Indicates T i The first-level receiving end level of the data packet, r 2,i Indicates the secondary receiving end level, b i represents the bandwidth requirement of the ith data packet, B represents the available bandwidth, and the bandwidth range is set from 1.25 Gbps symmetric bandwidth to 10 Gbps; represents the weight function of historical packet loss rate, ω i Represents the packet loss rate, and the historical packet loss rate weight function is as follows:

[0134]

[0135] In formula (2), P represents the detection packet loss rate, P min Indicates setting the minimum threshold of packet loss rate, P max represents the highest threshold of packet loss rate, k1 represents the weight influence coefficient to adjust the scheduling priority through historical data; in formula (1), φ(D j ) represents the queue length weight coefficient, D j Indicates the amount of data to be transmitted, through φ(D j )=ln(D j +1)+β logarithmic function maps the queue length weight to ensure that tasks with large data transmission volume obtain appropriate priority, and β represents the offset; weighted polling is used to determine the priority of transmitted data packets, and a resource allocation strategy is formulated to ensure that high-priority tasks obtain resources first to improve the overall efficiency and performance of the system; different ranges of inputs are mapped to appropriate weight factor values, and the weight function formula is as follows:

[0136]

[0137] In formula (3), where r 1,min Indicates the lower limit of the primary optical unit network receiving end in the value range, r 1,max represents the upper limit of the first-level optical unit network receiving end, w 1,min and w 1,max Respectively represent the minimum and maximum values ​​of the weight, the secondary optical unit network receiving end weight w2 calculation formula is the same, the linear transformation ensures that the input value is evenly distributed within the range and maps the corresponding weight factor value, balancing the primary and secondary receiving end levels on the priority p i The impact of

[0138] According to the calculated priority, the data packets are placed in the corresponding priority queue and bandwidth is allocated according to the order in which the priority data packets are sent. For each priority queue Q k According to the priority k, from high to low, calculate all the packets T in the current priority queue. i The bandwidth requirement b i sum satisfy Assigned to each of the current priority queues Q k Each of the data packets T i Bandwidth i , the bandwidth requirement calculation formula is as follows:

[0139]

[0140] In formula (4), x bIndicates the amount of data to be transmitted, b indicates the unit of bit, k indicates the ratio of extra overhead, the epon system has frame header overhead and MPCP protocol overhead for bandwidth allocation and time slot management, adds control information, sets Wireshark to capture and analyze Ethernet frames and protocol overhead, and the extra overhead ratio By capturing the total overhead ω and data size x consisting of the Ethernet frame header size, MPCP overhead and inter-frame spacing b Add the total overhead ω to calculate the EPON protocol overhead ratio to be 12%, k r Indicates the retransmission ratio. When data packets are lost during system transmission, the optical line terminal OLT transmitter receives continuous repeated confirmation instructions to determine that data is lost, and immediately retransmits the corresponding lost data packets. The retransmission ratio data table is statistically obtained as follows:

[0141] Table 1 Retransmission data table

[0142] Data volume Transfer time Amount of retransmitted data Total data volume Retransmission ratio 1 600 0.06 10.6 0.0566 1 587 0.04 10.4 0.3850 5 1789 0.05 1.05 0.0476 5 1800 0.05 1.06 0.0471 5 1806 0.26 5.26 0.0494 6 2013 0.30 6.30 0.0476 10 3600 0.50 10.50 0.0476 10 3605 0.52 10.52 0.0494 20 7200 1.00 21.00 0.0476 20 7224 0.98 20.98 0.0476

[0143] In Table 1, as the transmission data increases, the retransmission ratio stabilizes at 0.047, and the average retransmission ratio k is obtained. r is 4.76%; t represents the transmission time, and a OneAdvisor-800 delay measurement device is set to be connected between the optical line terminal OLT and the optical network unit ONU connected to the EPON network, and the sending and receiving time of each data packet is recorded to obtain the transmission time; η represents the network efficiency, which is obtained by the ratio of the actual transmission rate to the set theoretical maximum transmission rate, reflecting the actual utilization of the network; Indicates the data compression ratio. By allocating bandwidth reasonably, it can prevent certain devices or applications from occupying too much bandwidth, thereby avoiding network congestion, reducing packet loss, reducing delays and improving transmission efficiency. When , bandwidth is allocated through weighted fair queuing algorithm, and the bandwidth allocation formula is as follows:

[0144]

[0145] In formula (5), B i The weighted fair queuing algorithm determines the bandwidth allocated to data packet i, w i represents the weight factor value obtained in formula (2), B represents the total bandwidth available for allocation, Indicates the sum of the weight factor values ​​accumulated from data packet 1 to data packet n; allocates bandwidth reasonably according to each weight to ensure fair use of bandwidth resources and improve data transmission efficiency;

[0146] Determine the bandwidth allocation of the data packet to be forwarded. In the polling process, allocate resources according to the scheduling frequency of each data packet. The optical line terminal OLT converts the data packet into an optical signal and uses TDMA technology to divide the time into fixed time slots. In each time slot, the OLT transmits the data packet through the optical fiber network in EPON to the optical distribution network ODN according to the scheduling frequency and priority for subsequent data packet forwarding. The scheduling frequency formula is as follows:

[0147]

[0148] In formula (6), w i represents the weight of the ith packet, b i represents the bandwidth requirement of the ith data packet, represents the sum of all data packet weights, φ(D j ) represents the queue length weight coefficient, p i represents the priority of the weighted round-robin scheduling, represents the weight function of the historical packet loss rate, and λ represents the factor affecting the packet loss rate on the scheduling frequency; the scheduling frequency of each task is adjusted by the weight factor and the bandwidth requirement to determine the sending order of data packets with different priorities.

[0149] As a further embodiment of the present invention, the recorded data packet sending address information includes the MAC hardware address, physical port number and logical identifier of the optical network unit ONU, and the formula for allocating the logical identifier is as follows:

[0150] A id =A index ×W+λ bit (7)

[0151] In formula (7), all bits of the bitmap array are initialized to 0, A index Indicates traversing the bitmap array A and finding the first unused identifier position, W indicates the number of bits that the array element can hold, and λ bit Indicates the first 0bit position in the first element; sets the corresponding bit to 1 and returns an identifier; the optical line terminal OLT calls the allocation logical identifier, allocates a unique identifier to the ONU, and sends a confirmation message; the record forwarding rule includes a forwarding action and a rule for sending data packets of different priorities; the optical line terminal OLT determines to which ONU each received data packet should be forwarded, the forwarding action includes determining through which optical network unit ONU's downlink the data packet is sent to the target device, and the forwarding rule processes the priority sending order of different high-priority data packets to ensure the timeliness and reliability of important data.

[0152] As a further embodiment of the present invention, the primary optical network unit ONU adopts a Broadcom BCM56150 switching chip to enable the primary optical network unit ONU to dynamically learn the network topology information of the secondary optical network unit ONU, obtain the position and connection status through the link state protocol to calculate the best data transmission path, and use the best path calculation to help determine the best route from the primary optical network ONU to the destination secondary optical network ONU, ensuring that the data packet is transmitted in the network in the most efficient manner, reducing delay and transmission time. The transmission path implementation steps are as follows:

[0153] Step 1, initialize the ONU set, set the first-level optical network unit ONU to S, create an ONU set. For each ONU unit in the set v = S, set X dist (v) = 0, which does not match the source ONU setting of infinity, and is formatted as

[0154] Step 2: Update the node distance. Select the node with the smallest distance among the unprocessed ONUs, and update the distance of the neighbor node through the smallest ONU node. The update formula is as follows:

[0155]

[0156] In formula (8), X dist (u) represents the currently known shortest path length from the source node ONU to the secondary optical network unit u, u represents the ONU node with the shortest distance in the ONU set, v represents the unprocessed neighbor ONU node, α represents the adjustment coefficient, weighing the delay and load impact, ε delay (u,v) represents the transmission delay from u to v, b(u,v) represents the bandwidth from u to v, δ(u,v) represents the load from u to v, r represents the load weight coefficient, when the distance from the source node ONU to the neighbor ONU node v is greater than distance, then keep the updated distance and remove the minimum ONU node u from the ONU set, repeat the update until the set is empty to confirm the shortest path and the predecessor node; when the distance from the source node ONU to the neighbor ONU node v is less than or equal to If the distance is not known, there is no need to update the distance and update the node. The current path is not shorter or better than the known path length. By selecting the best path, it helps to achieve load balancing in the EPON network. Data packets can be dispersed to multiple paths to avoid path overload and other paths being idle, thereby improving the overall performance and efficiency of the network. At the same time, the system plans to add new secondary optical network unit ONU nodes. The best path calculation can quickly adapt to changes and update routing information to maintain network availability and stability.

[0157] Step 3: Obtain a data forwarding address, and determine the forwarding location through a hash function according to the IP address of the terminal device assigned by the optical line terminal OLT. The hash function formula is as follows:

[0158]

[0159] In formula (9), P s represents the IP address of the primary optical network unit ONU, s represents setting the primary optical network unit ONU as the source address unit, P dst Indicates the target IP address, dst indicates the target address unit, %N indicates the modulo budget, N indicates the total number of secondary ONU units, and receives and forwards data packets by determining the lower-level ONU unit number, and improves the performance and efficiency of the entire network through the hash function algorithm, which can effectively support large-scale data transmission; sets a forwarding identifier, the forwarding identifier is 1, and forwards the data packet according to the IEEE 802.1Q VLAN standard according to the acquired location information, and the forwarding identifier is 0, and no forwarding operation is performed, and the data packet needs to be forwarded to the optical line terminal OLT, and the optical line terminal OLT decides whether to transmit the data packet to the target ONU, and determines the shortest path through the two-level optical network unit to directly transmit data with the receiving unit and the traditional uplink needs to forward the data packet to the optical line terminal OLT, and the optical line terminal OLT controls the data packet to be forwarded to the other optical network unit ONU. The required timetable is as follows:

[0160] Table 2 Comparison of forwarding time for different packet sizes

[0161] Packet size Improved EPON Traditional EPON 1 1.35 2.08 5 1.52 2.66 10 1.87 3.34 15 2.00 3.41 20 2.26 3.67

[0162] In Table 2, for different data packet sizes, the time for the target optical network unit ONU to receive the forwarded data packet under the distribution network automation communication data packet forwarding method of the improved EPON technology of the present invention is shorter than the time for the traditional EPON system forwarding method to forward the data packet to the target optical network unit ONU, and as the data packet continues to increase, the transmission time is reduced more significantly. The timetable required for the distribution network automation communication data packet forwarding method of the improved EPON technology and the traditional EPON system forwarding method under different forwarding data packet numbers is as follows:

[0163] Table 3 Comparison of forwarding time for different numbers of data packets

[0164] Number of packets Improved EPON Traditional EPON 10 1.81 3.00 20 2.12 4.03 50 2.66 4.55 100 3.91 5.86 200 4.85 7.04

[0165] In Table 3, under the same data packet size and different forwarding data packet numbers, the improved EPON technology's distribution network automation communication data packet forwarding method requires a shorter time. As the number of data packets increases, the transmission time will increase accordingly. The time required for transmission will be affected and changed by network load, equipment performance, and path length, but the transmission efficiency is still significantly improved, thereby improving the efficiency of automated communication.

[0166] As a further embodiment of the present invention, the hardware structure of the improved EPON technology distribution network automation communication data packet forwarding method includes:

[0167] Optical line terminal OLT, configured with the load output end of the distribution network, is used to receive data packets, record the data packet sending address information and forwarding rules, and set the user end IP address;

[0168] Optical Distribution Network (ODN), used for transmission and distribution of optical signals;

[0169] The primary optical network unit ONU is used to parse the packet header information, extract the destination address, and forward the packet to the secondary optical network unit ONU;

[0170] Secondary optical network unit ONU, used to receive optical transmission network data, convert it into electrical signals and transmit it to user equipment;

[0171] The output end of the optical line terminal OLT is connected to the input end of the optical distribution network ODN, the output end of the optical distribution network ODN is connected to the input end of the primary optical network unit ONU, and the output end of the primary optical network unit ONU is connected to the input end of the secondary optical network unit ONU.

[0172] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these specific embodiments are only illustrative, and those skilled in the art can make various omissions, substitutions and changes to the details of the above methods and systems without departing from the principles and essence of the present invention. For example, merging the above method steps so as to perform substantially the same functions in substantially the same manner to achieve substantially the same results is within the scope of the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

Claims

1. A method for forwarding data packets for distribution network automation communication based on improved EPON technology, characterized in that: The following steps are involved: Step 1: Data packet classification and scheduling: According to the communication requirements of distribution network automation, data packets are classified into different priorities and the sending order of data packets of different priorities is determined through weighted round-robin scheduling; Step 2: The optical line terminal OLT receives the data packet and records the data packet sending address information and forwarding rules; Step 3, the optical network unit ONU parses the data packet header information, extracts the target address and forwarding rules, obtains the link state protocol position and connection status to calculate the best data transmission path, and obtains the forwarding optical network unit ONU position information; Step 4: Monitor and manage the running status to ensure the stability and reliability of data packet forwarding, synchronize the optical line terminal OLT flow table with the optical network unit flow table, and maintain the latest forwarding rules.

2. The method for forwarding data packets for distribution network automation communication based on the improved EPON technology according to claim 1, characterized in that: In step (1), the weighted round-robin scheduling priority calculation formula is as follows: In formula (1), w1 represents the weight of the primary optical network unit ONU receiving end, w2 represents the weight of the secondary optical unit network ONU receiving end, and r 1,i Indicates T i The first-level receiving end level of the data packet, r 2,i Indicates the secondary receiving end level, b i represents the bandwidth requirement of the ith data packet, and B represents the available bandwidth; represents the weight function of historical packet loss rate, ω i represents the packet loss rate, φ(D j ) represents the queue length weight coefficient, D j Indicates the amount of data to be transmitted; the historical packet loss rate weight function is as follows: In formula (2), P represents the detection packet loss rate, P min Indicates setting the minimum threshold of packet loss rate, P max represents the highest threshold of packet loss rate, k1 represents the weight influence coefficient, and the scheduling priority is adjusted through historical data; j )=ln(D j +1)+β logarithmic function maps the queue length weight to ensure that tasks with large data transmission volume get appropriate priority, β represents the offset; different ranges of inputs map appropriate weight factor values, and the weight function formula is as follows: In formula (3), where r 1,min Indicates the lower limit of the primary optical unit network receiving end in the value range, r 1,max represents the upper limit of the first-level optical unit network receiving end, w 1,min and w 1,max Respectively represent the minimum and maximum values ​​of the weight, the secondary optical unit network receiving end weight w2 calculation formula is the same, the linear transformation ensures that the input value is evenly distributed within the range and maps the corresponding weight factor value, balancing the primary and secondary receiving end levels to the priority p i In the polling process, resources are allocated according to the scheduling frequency of each data packet. The scheduling frequency formula is as follows: In formula (4), w i represents the weight of the ith packet, b i represents the bandwidth requirement of the ith data packet, represents the sum of all data packet weights, φ(D j ) represents the queue length weight coefficient, p i represents the priority of the weighted round-robin scheduling, represents the weight function of the historical packet loss rate, and λ represents the factor affecting the packet loss rate on the scheduling frequency; the scheduling frequency of each task is adjusted by the weight factor and the bandwidth requirement to determine the sending order of data packets with different priorities.

3. The method for forwarding data packets of distribution network automation communication based on the improved EPON technology according to claim 1, characterized in that: In step (2), the recorded data packet sending address information includes the MAC hardware address, physical port number and logical identifier of the optical network unit ONU, and the formula for allocating the logical identifier is as follows: A id =A index ×W+λ bit (5) In formula (5), all bits of the bitmap array are initialized to 0, A index Indicates traversing the bitmap array A and finding the first unused identifier position, W indicates the number of bits that the array element can hold, and λ bit Indicates the first 0bit position in the first element; sets the corresponding bit to 1 and returns an identifier, the optical line terminal OLT calls the allocation logical identifier, allocates a unique identifier for the ONU, and sends a confirmation message; the record forwarding rule includes the forwarding action and the sending order rules of the different priority data packets.

4. The method for forwarding data packets of distribution network automation communication based on the improved EPON technology according to claim 1, characterized in that: In step (3), the Broadcom BCM56150 switching chip is used to enable the primary optical network unit ONU to dynamically learn the network topology information of the secondary optical network unit ONU, and the position and connection status are obtained through the link state protocol to calculate the best data transmission path. The transmission path implementation steps are as follows: Step 1: Initialize the ONU set, set the first-level optical network unit ONU to S, create an ONU set. For each ONU unit in the set v = S, set X dist (v) = 0, which does not match the source ONU setting of infinity, and is formatted as Step 2: Update the node distance. Select the node with the smallest distance among the unprocessed ONUs, and update the distance of the neighbor node through the smallest ONU node. The update formula is as follows: In formula (6), X dist (u) represents the currently known shortest path length from the source node ONU to the secondary optical network unit u, u represents the ONU node with the shortest distance in the ONU set, v represents the unprocessed neighbor ONU node, α represents the adjustment coefficient, weighing the delay and load impact, ε delay (u,v) represents the transmission delay from u to v, b(u,v) represents the bandwidth from u to v, δ(u,v) represents the load from u to v, and r represents the load weight coefficient. When the distance from the source ONU to the neighbor ONU node v is greater than If the distance is greater than 100, the updated distance is retained and the minimum ONU node u is removed from the ONU set, and the update is repeated until the set is empty to confirm the shortest path and the predecessor node; Step 3: Obtain a data forwarding address, and determine the forwarding location through a hash function according to the IP address of the terminal device assigned by the optical line terminal OLT. The hash function formula is as follows: In formula (7), P s represents the IP address of the primary optical network unit ONU, s represents setting the primary optical network unit ONU as the source address unit, P dst represents the destination IP address, dst represents the destination address unit, %N represents the modulo budget, and N represents the total number of secondary ONU units; Set the forwarding identifier. If the forwarding identifier is 1, the data packet is forwarded through the IEEE802.1Q VLAN standard according to the acquired location information. If the forwarding identifier is 0, no forwarding operation is performed.

5. An improved EPON technology distribution network automation communication data packet forwarding system, characterized in that: A method for forwarding data packets for distribution network automation communication using an improved EPON technology according to any one of claims 1 to 4, characterized in that: the system comprises: Optical line terminal OLT, configured with the load output end of the distribution network, is used to receive data packets, record the data packet sending address information and forwarding rules, and set the user end IP address; Optical Distribution Network (ODN), used for transmission and distribution of optical signals; The primary optical network unit ONU is used to parse the packet header information, extract the destination address, and forward the packet to the secondary optical network unit ONU; Secondary optical network unit ONU, used to receive optical transmission network data, convert it into electrical signals and transmit it to user equipment; The output end of the optical line terminal OLT is connected to the input end of the optical distribution network ODN, the output end of the optical distribution network ODN is connected to the input end of the primary optical network unit ONU, and the output end of the primary optical network unit ONU is connected to the input end of the secondary optical network unit ONU.

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