Train communication network topology structure based on ECN and ETBN and data transmission method

Abstract

The embodiment of the invention discloses a train communication network topological structure based on an ECN and an ETBN and a data transmission method. The train communication network topological structure and the data transmission method are used for improving the reliability and the stability of train communication. The structure comprises a first ECN, a second ECN, a third ECN and a fourth ECN, wherein the first ECN, the second ECN, the third ECN and the fourth ECN are arranged in all carriages of a train; the first ETBN, the second ETBN, the third ETBN and the fourth ETBN are arranged on a backbone network head train of the train; the first ETBN, the second ETBN, the third ETBN and the fourth ETBN form an ETBN network layer; the first ECN and the second ECN of each compartment in the train form a first ECN network layer, and the third ECN and the fourth ECN of each compartment in the train form a second ECN network layer; the ETBN network layer is located between the first ECN network layer and the second ECN network layer.

Description

Technical Field

[0001] The present application relates to the technical field of train networks, and in particular to a train communication network topology structure and a data transmission method based on ECN and ETBN. Background Art

[0002] The traditional train communication network topology is mainly composed of a two-layer structure consisting of the train-level Ethernet train backbone (ETB) and the vehicle-level Ethernet communication network (ECN). Among them, ETB is mainly responsible for the transmission of train-level data, working at the network layer, and is used to realize data communication between two network segments; ECN works at the data link layer to realize the function of a switch.

[0003] The traditional train communication network topology cannot guarantee that data can reach the destination at the scheduled time during data transmission, nor can it guarantee the transmission order of data packets, or whether data packets can arrive reliably. This service mode is called "best effort", that is, the network will do its best to transmit data, but does not provide any quality of service (QoS) guarantee. Therefore, in order to meet the real-time and deterministic requirements of rail transit communication networks, it is necessary to design a train communication network topology to ensure that data can still be transmitted normally when the network fluctuates and is congested, and to avoid the loss of critical data. Summary of the invention

[0004] In order to solve at least one technical problem in the above-mentioned background technology, the present application proposes a train communication network topology structure and a data transmission method based on ECN and ETBN.

[0005] In order to achieve the above object, according to one aspect of the present application, a train communication network topology structure based on ECN and ETBN is provided, the structure comprising:

[0006] A first ECN, a second ECN, a third ECN and a fourth ECN are arranged in each carriage of the train, the first ECN is connected to the second ECN and the third ECN respectively, and the third ECN is connected to the fourth ECN;

[0007] The first ETBN, the second ETBN, the third ETBN and the fourth ETBN are arranged in the backbone network head car of the train, the first ETBN and the second ETBN are arranged in the first car of the backbone network head car, and the third ETBN and the fourth ETBN are arranged in the last car of the backbone network head car; the first ETBN is connected to the second ETBN, the first ETBN is connected to the first ECN and the third ECN of the first car, and the second ETBN is connected to the second ECN and the fourth ECN of the first car; the third ETBN is connected to the fourth ETBN, the third ETBN is connected to the first ECN and the third ECN of the last car, and the fourth ETBN is connected to the second ECN and the fourth ECN of the last car;

[0008] The first ETBN, the second ETBN, the third ETBN and the fourth ETBN form an ETBN network layer; the first ECN and the second ECN of each carriage in the train form the first ECN network layer, and the third ECN and the fourth ECN of each carriage in the train form the second ECN network layer; the ETBN network layer is located between the first ECN network layer and the second ECN network layer.

[0009] Furthermore, the train communication network topology structure is divided into a first logical link and a second logical link. The first ETBN, the second ETBN, the first ECN of the first car, the second ECN of the first car, the second ECN of the last car, the first ECN of the last car, the fourth ETBN and the third ETBN constitute the first logical link; the first ETBN, the second ETBN, the third ECN of the first car, the fourth ECN of the first car, the fourth ECN of the last car, the third ECN of the last car, the fourth ETBN and the third ETBN constitute the second logical link.

[0010] Further, the first ETBN of the adjacent train is connected to the third ETBN.

[0011] Further, the clock priorities between the first ETBN and the third ETBN of the adjacent trains are synchronized.

[0012] Furthermore, the VRRP protocol runs between the first ETBN and the second ETBN; and the VRRP protocol runs between the third ETBN and the fourth ETBN.

[0013] Furthermore, if the train is a single-unit train, the ETBN network layer is not started;

[0014] If the train is a coupled train, the ETBN network layer is used to determine whether to start the ETBN at the coupled end of the train based on the obtained port status of the train. The coupled end of the train is used to represent the end where the train is connected to the adjacent train.

[0015] Further, if the ETBN at the reconnected end of the train is activated, the ETBN at the reconnected end is used to determine whether to send train-level information to the ETBN at the other end based on the activation status of the ETBN at the other end of the train.

[0016] Furthermore, the clock priority of the ECN in the first car of the train is set to 127, the clock priority of the ECN in the last car is set to 128, and the clock priority of the ECN in other cars is set to 246; the clock priority of the ETBN in the train is set to 247.

[0017] Furthermore, the ECN and ETBN in the train support the TSN protocol.

[0018] In order to achieve the above object, according to another aspect of the present application, a data transmission method is provided, which is applied to the above train communication network topology based on ECN and ETBN, including:

[0019] The ETBN network layer obtains the train data sent by the terminal equipment;

[0020] The ETBN network layer divides the train data into different transmission queues based on the priority in the VLAN tag of the train data to realize the transmission of the train data.

[0021] The beneficial effects of the present application are: by setting the ETBN network layer in the middle of the ECN network layer, a more balanced and optimized network topology is formed, the delay of data transmission is reduced, and the overall performance of the network is improved. In addition, two redundant ETBNs are set in the first car and the last car respectively, which ensures the reliability of data transmission. In addition, by removing the ETB bus inside the car, the use of train-level buses and repeaters is reduced, the wiring is simplified, and the cost and failure points are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0023] Figure 1 It is a train communication network topology structure based on ECN and ETBN provided in an embodiment of the present application;

[0024] Figure 2 It is a flow chart of a data transmission method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0026] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0027] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0028] As described in the background technology, the traditional train communication network topology cannot meet the real-time and deterministic requirements of the rail transit communication network. In addition, the traditional ETBN topology connection method usually relies on the train-level bus (ETB) that runs through the entire train. This design requires that each car is connected through the ETB bus, and at the same time, data transmission between cars needs to rely on repeaters. This not only increases the complexity and cost of wiring, but also leads to more failure points.

[0029] Based on this, the present application provides a train communication network topology structure and data transmission method based on the ECN network and the ETBN network. Figure 1 As shown, it is a structural schematic diagram of a train communication network topology structure based on an ECN network and an ETBN network provided in an embodiment of the present application, and the topology structure specifically includes the following contents:

[0030] A first ECN, a second ECN, a third ECN and a fourth ECN are arranged in each carriage of the train, the first ECN is connected to the second ECN and the third ECN respectively, and the third ECN is connected to the fourth ECN;

[0031] The first ETBN, the second ETBN, the third ETBN and the fourth ETBN are arranged in the backbone network head car of the train, the first ETBN and the second ETBN are arranged in the first car of the backbone network head car, and the third ETBN and the fourth ETBN are arranged in the last car of the backbone network head car; the first ETBN is connected to the second ETBN, the first ETBN is connected to the first ECN and the third ECN of the first car, and the second ETBN is connected to the second ECN and the fourth ECN of the first car; the third ETBN is connected to the fourth ETBN, the third ETBN is connected to the first ECN and the third ECN of the last car, and the fourth ETBN is connected to the second ECN and the fourth ECN of the last car;

[0032] The first ETBN, the second ETBN, the third ETBN and the fourth ETBN form an ETBN network layer; the first ECN and the second ECN of each carriage in the train form the first ECN network layer, and the third ECN and the fourth ECN of each carriage in the train form the second ECN network layer; the ETBN network layer is located between the first ECN network layer and the second ECN network layer.

[0033] It should be noted that the first and last carriages of the train are the backbone network head cars of the train, and two ETBNs are respectively set for the first and last carriages. Figure 1 For example, Figure 1 The train shown has a total of 8 carriages (not all carriages are shown), and the first carriage (car 1) and the last carriage (car 8) of the train are the backbone network head carriages of the train. The first ETBN and the second ETBN are set in car 1, and the third ETBN and the fourth ETBN are set in car 8. The first ETBN in car 1 is connected to the first ECN and the third ECN in car 1, and the second ETBN in car 1 is connected to the second ECN and the fourth ECN in car 1. The connection in car 8 is similar to that in car 1, the third ETBN in car 8 is connected to the first ECN and the third ECN in car 8, and the fourth ETBN in car 8 is connected to the second ECN and the fourth ECN in car 8.

[0034] In some embodiments, the ECN network layer adopts a ring topology redundancy. If any ECN on the transmission path fails, a new transmission path is re-determined through the ring network protocol for data transmission.

[0035] It can be understood that the naming of the first ECN, the second ECN, the third ECN and the fourth ECN in the present application is mainly for the convenience of describing the technical solution of the present application. In fact, the four ECNs of each carriage can be the same or different, and can be set according to the actual situation. In the actual application process, the ECNs in the carriage can be named according to the carriage number. For example, Figure 1For example, the first ECN and the third ECN in car 1 can be uniformly named ECN11 to represent the first ECN and the third ECN, and the third ECN and the fourth ECN in car 1 can be uniformly named ECN12 to represent the third ECN and the fourth ECN at the same time. Similarly, the first ECN and the third ECN in car 8 can be uniformly named ECN81 to represent the first ECN and the third ECN at the same time, and the third ECN and the fourth ECN in car 8 can be uniformly named ECN82 to represent the third ECN and the fourth ECN at the same time. Similar naming is also available in this application, which will not be repeated in this application, and its specific naming can be set according to actual conditions.

[0036] In this way, by setting up the ETBN network layer in the middle of the ECN network layer, a more balanced and optimized network topology is formed, the delay of data transmission is reduced, and the overall performance of the network is improved. In addition, two redundant ETBNs are set up in the first car and the last car respectively to ensure the reliability of data transmission. In addition, by removing the ETB bus inside the car, the use of train-level buses and repeaters is reduced, the wiring is simplified, and the cost and failure points are reduced.

[0037] In some embodiments, according to the 802.1Qci standard, the ETBN may limit the ingress frame rate and egress frame rate from the marshaling network or directly connected terminal devices.

[0038] Specifically, ETBN can limit the data frame rate entering from the marshaling network, and can also limit the data frame rate sent from the directly connected terminal device to the network. By setting the speed limit threshold, it can prevent excessive data from flooding into the network and avoid network congestion. When the network traffic exceeds the set threshold, ETBN will prioritize the transmission of low-priority messages to ensure that high-priority data can be transmitted first.

[0039] In some embodiments, Figure 1 As shown, the train communication network topology structure is divided into a first logical link and a second logical link. The first ETBN, the second ETBN, the first ECN of the first car, the second ECN of the first car, the second ECN of the last car, the first ECN of the last car, the fourth ETBN and the third ETBN constitute the first logical link; the first ETBN, the second ETBN, the third ECN of the first car, the fourth ECN of the first car, the fourth ECN of the last car, the third ECN of the last car, the fourth ETBN and the third ETBN constitute the second logical link.

[0040] For example, Figure 1As shown in car A, the first and third ETBNs of car A process the data of the first logical link, and the second and fourth ETBNs of car A process the data of the second logical link. ETB discovers and manages link groups in the network through TTDP HELLO frames to ensure the availability of logical links.

[0041] It can be understood that both the first logic line and the second logic line are ETB lines. It supports five data types, namely: monitoring data, process data, message data, flow data and best effort data. Different types of data correspond to different priorities. Taking best effort data as an example, its lowest priority is 0 or 1.

[0042] In this way, two redundant logical links are formed through the ETBN of the first car and the last car. Even if one link fails, data can still be transmitted through the other link, ensuring that the transmission of critical data is not affected.

[0043] In some embodiments, Figure 1 As shown, different types of links are used to connect different devices. Specifically, Figure 1 The A link in the figure is the first logical link, which is a connection link between trains and is used for data transmission between trains and the outside world. The B link is the second logical link, which is similar to the A link, and is a connection link between trains and is used for data transmission between trains and the outside world, and the A link and the B link are redundant. The C link is the connection link between the ETBN and the first ECN network layer. Since the essence of the ETBN is a gateway device, it is equivalent to the role of a terminal device in the ENC network layer. Therefore, the C link is also called the connection link between the terminal device and the first ECN network layer. The D link is similar to the C link, which is a connection link between the ETBN and the second ECN network layer, and is redundant with the C link. The E link is the connection line between ECNs, which is actually the connection between Ethernet switches and belongs to the internal bus of the train.

[0044] From the above content, we can know that link A and link B are mutually redundant, and link C and link D are mutually redundant. When one of the two redundant links fails, the other redundant link can take over immediately to ensure that data transmission is not interrupted and improve the stability of data transmission.

[0045] In some embodiments, a virtual router redundancy (VRRP) protocol is run between the first ETBN and the second ETBN of the first car, and a virtual router redundancy (VRRP) protocol is run between the third ETBN and the fourth ETBN of the last car.

[0046] In this way, through the VRRP protocol, adjacent ETBNs in the train (such as the first ETBN and the second ETBN, the third ETBN and the fourth ETBN) will detect each other's status to ensure that they work normally. In addition, adjacent ETBNs share a virtual unified IP address that is visible to the outside world, and the terminal (ED) can access the corresponding ETBN through the IP address. In the actual operation process, one of the ETBNs will serve as the main server and the other ETBN will serve as the backup server. If the main server fails, the other ETBN will immediately take over and the backup server will be converted to the new main server to continue processing the data to be transmitted. The whole process is transparent to the outside world, and external devices (such as terminals) will not notice the switching of ETBNs, which improves the fault tolerance and reliability of data transmission.

[0047] In some embodiments, the ECN and ETBN in the train support the TSN protocol.

[0048] Among them, TSN is a set of protocol standards developed by the IEEE802.1TSN task group. This standard defines the time-sensitive mechanism of Ethernet data transmission. It ensures the transmission performance of business traffic in Ethernet through mechanisms such as traffic group priority forwarding, scheduling mechanism line clearing, and bandwidth reservation, adding certainty and reliability to standard Ethernet to ensure that Ethernet can provide a stable and consistent service level for the transmission of critical data. The real-time performance of TSN is mainly achieved through the IEEE8-2.1Qbv function. The difference is that the traditional Ethernet IEEE802.1Qbu+IEEE802.3br uses a preemptive MAC method to transmit high real-time data. IEEE802.1Qbv uses TimeAware Shaper to provide a dedicated time channel for high real-time data, and uses the Best Effort method to transmit other non-real-time data; its implementation principle is that during the entire process of end-to-end transmission of data packets, the TSN network performs comprehensive data packet packing optimization for each key protocol / control information / data flow on the entire network, accurately defines the priority of data packets in each forwarding process, and all point-to-point paths are prioritized and designated channels in advance to ensure the real-time and accuracy of key data.

[0049] Specifically, between ETBN and ECN that support the TSN protocol, the time synchronization of each device in the network is achieved through the IEEE802.1AS time synchronization protocol.

[0050] In some embodiments, the clock priority of the ECN in the first car of the train is set to 127, the clock priority of the ECN in the last car is set to 128, and the clock priority of the ECN in other cars is set to 246; the clock priority of the ETBN in the train is set to 247.

[0051] Specifically, Figure 1 Taking the topology shown in the figure as an example, the ECN of car 1 (the first ECN, the second ECN, the third ECN and the fourth ECN) is set to the highest priority (127) as the scheduled master clock, and the ECN of car 8 (the first ECN, the second ECN, the third ECN and the fourth ECN) is set to 128 as the backup master clock. The clock priority of the ECN of other cars is set to 246, as a normal clock, which will synchronize its own clock according to the master clock. The clock priority of the subsystem is set to 255, which is fixed as a slave clock.

[0052] It is understandable that for data transmitted in the train's communication network, the same time standard is more conducive to data transmission, especially data transmitted based on the TSN protocol with strong timeliness. ECN clock synchronization can better realize the arbitrary transmission of the above data in the entire train. At the same time, there is clock redundancy between the scheduled master clock and the backup master clock, which further ensures the clock synchronization of the train communication network, thereby ensuring the timely and stable transmission of important train data.

[0053] In some embodiments, the first ETBN of the adjacent train is connected to the third ETBN.

[0054] For example, Figure 1 As shown, the network topology structures of adjacent trains are consistent, and the first ETBN of one train is connected to the third ETBN of another train, still forming two mutually redundant first logical links (also called ETB A path) and second logical links (also called ETB B path).

[0055] In some embodiments, the first ETBN and the third ETBN of the adjacent trains communicate based on the TTDP protocol.

[0056] The TTDP protocol includes the TTDP HELLO protocol and the TTDP TOPO protocol. Specifically, the TTDP HELLO frame is used to obtain the device information of the adjacent ETBN and manage the link status. The TTDP TOPO frame can be sent to all ETBNs to obtain the device information of all ETBNs and form a network index table of the multi-group network.

[0057] In some embodiments, the clock priorities between the first ETBN and the third ETBN of adjacent trains are synchronized.

[0058] Specifically, the clock priority of the ETBNs of adjacent trains is uniformly set to 247 to achieve the uniform clock priority of adjacent trains. In the case of train reconnection (i.e., multiple trains are connected to each other), since the ECN clock priority of car 1 of each train is 127, the clock of the ECN with the smallest MAC address is selected as the master clock of the entire network of the reconnected train. It can be understood that the ETBN of each train only synchronizes the clock priority (also known as time synchronization) with the ETBN of the adjacent train, so that Figure 1 For example, the time priority between the third ETBN of train A and the first ETBN of train B is synchronized, but the ETBN of the adjacent train is not synchronized with the ECN time. Since ECN is mainly used for data transmission within the vehicle, and ETBN is responsible for train-level data transmission, the time synchronization requirements and mechanisms of the two are different. In addition, the traffic scheduling of ETBN depends on the time synchronized by gPTP to ensure that the data packets are transmitted within the predetermined time window, improving the real-time and deterministic nature of data transmission. The gPTP time is the precise time synchronized by the 802.1AS protocol, which is used to ensure that all ETBNs perform traffic scheduling on the same time basis.

[0059] In some embodiments, DSCP and QoS mapping is enabled on the device ports of the ECNs (eg, the first ECN, the second ECN, the third ECN, and the fourth ECN) disposed in the train.

[0060] Specifically, the ECN in the train uses DSCP to distinguish the priorities of different traffic. ECN maps traffic to different priority queues according to different DSCP values, and optimizes the processing order of data packets by configuring the scheduling table. Data packets with higher priorities are processed first to ensure that data flows with higher latency requirements are not delayed.

[0061] As a possible implementation method, the ECN switch configures a scheduling table according to the priority of the traffic.

[0062] The scheduling table includes the scheduling cycle, the gated entry queue switch state, and the gated entry duration. The scheduling cycle determines the cycle time when the device processes different queues, such as polling or time slice configuration. The gated entry queue switch state is used to manage the on or off state of the queue to prevent excessive traffic backlog from causing network congestion. The gated entry duration is related to the gated entry queue switch state. The duration determines whether certain queues can continue to receive or send data packets, thereby optimizing traffic processing.

[0063] In some embodiments, ETBN adjusts the transmission time and bandwidth of data frames according to the priority in the VLAN tag by configuring 802.1Qbv time-aware (gated) shaper to ensure that high-priority data can obtain more transmission resources. At the same time, by configuring IEEE 802.1Qci, the ingress and egress frame rates from the aggregation network or directly connected terminal devices can be limited to control network traffic and ensure that traffic of different service categories can obtain appropriate resources. These two technologies work together to improve network performance and reliability, especially for time-sensitive and bandwidth-sensitive applications.

[0064] In some embodiments, if the train is a single-unit train, the ETBN network layer is not started;

[0065] If the train is a coupled train, the ETBN network layer is used to determine whether to start the ETBN at the coupled end of the train based on the obtained port status of the train. The coupled end of the train is used to represent the end where the train is connected to the adjacent train.

[0066] Specifically, when the train is a single-unit train (the train has only one unit and is not connected to other trains), the ETBN network layer will not be activated and will not participate in the data transmission process. The data communication within the single-unit train is completed through the vehicle-level ECN network layer.

[0067] When the train is a multiple-unit train, Figure 1 Taking the topology shown as an example, the reconnected train includes cars A and B. At the connection between cars A and B, the third ETBN of car A belongs to the ETBN of the reconnected end of car A, and the first ETBN of car B belongs to the ETBN of the reconnected end of car B. When data transmission is required, the third ETBN of car A and the first ETBN of car B respectively detect their own port status (i.e., whether there is a valid physical connection) to determine whether they are activated. If the port is in the link up state, indicating that there is a valid physical connection, the third ETBN of car A and the first ETBN of car B are activated to form the ETBN network layer, and start to perform train-level data transmission tasks to ensure that data between different marshalings can be transmitted correctly and efficiently. At the same time, the data inside the carriages of each train is still transmitted through the ECN network layer.

[0068] In some embodiments, if the ETBN at the reconnecting end of the train is activated, the ETBN at the reconnecting end is used to determine whether to send train-level information to the ETBN at the other end of the train based on the activation status of the ETBN at the other end.

[0069] Specifically, when the number of coupled trains is greater than 2, the activation rules of the ETBN network layer still apply, as described above. In addition, the activated ETBN will obtain the activation status of the ETBN at the other end of the same train. If the ETBN at the other end is also activated, the two ETBNs can share train-level information. The ETBN at the coupled end sends train-level information to the ETBN at the other end, so that more coordinated data transmission can be achieved between multiple train trains, further enhancing the reliability and efficiency of the entire communication network. For example, Figure 1 For the column, assume Figure 1 The number of coupled trains is greater than 2. When the third ETBN of car A is activated, the third ETBN obtains the activation status of the first ETBN of car A. If the first ETBN is activated, the third ETBN of car A and the first ETBN share train-level information.

[0070] In this way, by setting up the ETBN network layer in the middle of the ECN network layer, a more balanced and optimized network topology is formed, the delay of data transmission is reduced, and the overall performance of the network is improved. In addition, two redundant ETBNs are set up in the first car and the last car respectively to ensure the reliability of data transmission. In addition, by removing the ETB bus inside the car, the use of train-level buses and repeaters is reduced, the wiring is simplified, and the cost and failure points are reduced.

[0071] In addition, both ECN and ETBN in the topology structure provided by this application support the TSN protocol. Through the priority division and scheduling mechanism of TSN technology, real-time control data is ensured to be transmitted first, improving the real-time performance of data transmission. And through TSN's time synchronization, data scheduling, network configuration and other mechanisms, nanosecond-level deterministic services are provided to reduce the complexity of the entire communication network.

[0072] like Figure 2 As shown, a data transmission method provided in an embodiment of the present application is applied to the above-mentioned train communication network topology based on ECN and ETBN, and specifically includes the following steps:

[0073] S101. The ETBN network layer obtains the train data sent by the terminal device.

[0074] Among them, the train data carries a VLAN tag. For example, taking the train data as an ETBN message, the ETBN carries a VLAN tag when entering the port. The priority field (IEEE 802.1QVLAN priority field) in the VLAN tag is defined as 3 bits, representing 0-7. The larger the number, the higher the priority. Different types of traffic data correspond to different priorities. The specific definitions are as follows:

[0075] Best-effort data: priority 0 or 1;

[0076] Traditional TRDP message data and audio and video data: priority 2;

[0077] TRDP process data that does not support TSN: Priority 3;

[0078] TSN data stream: priority 4, 5, 6;

[0079] High-priority management protocol data (such as PTP synchronization messages and TTDP messages): priority 7.

[0080] S102. The ETBN network layer divides the train data into different transmission queues based on the priority in the VLAN tag of the train data to realize the transmission of the train data.

[0081] Specifically, by configuring 802.1Qbv gating entries, the transmission of data of different priorities within a specific time window is controlled. For example, the duration of a gating entry with a high priority will be set longer to ensure that high-priority data will have more transmission time and bandwidth. Among them, 802.1Qbv is part of the TSN standard and is used for time-aware shaping.

[0082] In this way, prioritization and queue management ensure that data packets are prioritized, while the time-aware shaper further ensures that high-priority data is transmitted first within a specific time window. This comprehensive mechanism effectively guarantees the real-time and reliability of critical data, meeting the stringent requirements of rail transit communication networks.

[0083] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A train communication network topology based on ECN and ETBN, characterized in that: include: A first ECN, a second ECN, a third ECN and a fourth ECN are arranged in each carriage of the train, wherein the first ECN is connected to the second ECN and the third ECN respectively, and the third ECN is connected to the fourth ECN; A first ETBN, a second ETBN, a third ETBN and a fourth ETBN are arranged in the backbone network head car of the train, wherein the first ETBN and the second ETBN are arranged in the first car of the backbone network head car, and the third ETBN and the fourth ETBN are arranged in the last car of the backbone network head car; The first ETBN is connected to the second ETBN, the first ETBN is connected to the first ECN and the third ECN of the first carriage, and the second ETBN is connected to the second ECN and the fourth ECN of the first carriage; The third ETBN is connected to the fourth ETBN, the third ETBN is connected to the first ECN and the third ECN of the last carriage, and the fourth ETBN is connected to the second ECN and the fourth ECN of the last carriage; The first ETBN, the second ETBN, the third ETBN and the fourth ETBN form an ETBN network layer; the first ECN and the second ECN of each carriage in the train form a first ECN network layer, and the third ECN and the fourth ECN of each carriage in the train form a second ECN network layer; the ETBN network layer is located between the first ECN network layer and the second ECN network layer.

2. The train communication network topology structure according to claim 1 is characterized in that: The train communication network topology structure is divided into a first logical link and a second logical link. The first ETBN, the second ETBN, the first ECN of the first car, the second ECN of the first car, the second ECN of the last car, the first ECN of the last car, the fourth ETBN and the third ETBN constitute the first logical link; the first ETBN, the second ETBN, the third ECN of the first car, the fourth ECN of the first car, the fourth ECN of the last car, the third ECN of the last car, the fourth ETBN and the third ETBN constitute the second logical link.

3. The train communication network topology structure according to claim 2 is characterized in that: The first ETBN of the adjacent train is connected to the third ETBN.

4. The train communication network topology structure according to claim 3 is characterized in that: The clock priorities between the first ETBN and the third ETBN of the adjacent trains are synchronized.

5. The train communication network topology structure according to claim 1, characterized in that: The VRRP protocol runs between the first ETBN and the second ETBN; and the VRRP protocol runs between the third ETBN and the fourth ETBN.

6. The train communication network topology structure according to claim 2, characterized in that: If the train is a single-unit train, the ETBN network layer is not started; If the train is a coupled train, the ETBN network layer is used to determine whether to start the ETBN located at the coupled end of the train based on the acquired port status of the train, and the coupled end of the train is used to represent the end where the train is connected to an adjacent train.

7. The train communication network topology structure according to claim 6, characterized in that: If the ETBN at the reconnected end of the train is activated, the ETBN at the reconnected end is used to determine whether to send train-level information to the ETBN at the other end based on the activation state of the ETBN at the other end of the train.

8. The train communication network topology structure according to claim 1, characterized in that: The clock priority of the ECN of the first carriage in the train is set to 127, the clock priority of the ECN of the last carriage is set to 128, and the clock priority of the ECN of other carriages is set to 246; The clock priority of the ETBN in the train is set to 247.

9. The train communication network topology structure according to claim 1, characterized in that: The ECN and ETBN in the train support the TSN protocol.

10. A data transmission method, characterized in that: The train communication network topology structure based on ECN and ETBN as described in any one of claims 1 to 9 comprises: The ETBN network layer obtains the train data sent by the terminal equipment; The ETBN network layer divides the train data into different transmission queues based on the priority in the VLAN tag of the train data to achieve transmission of the train data.

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