Train communication network topology and data transmission method based on ecn and etbn

Abstract

The embodiment of the application discloses a train communication network topology structure and a data transmission method based on ECN and ETBN, which are used for improving the reliability and stability of train communication. The structure comprises: a first ECN, a second ECN, a third ECN and a fourth ECN arranged in each carriage of a train; a first ETBN, a second ETBN, a third ETBN and a fourth ETBN arranged in a backbone network head carriage 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 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; and 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 network, in particular to a train communication network topology structure and data transmission method based on ECN and ETBN. BACKGROUND

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

[0003] The traditional train communication network topology structure cannot guarantee that data can reach the destination according to the predetermined time, the transmission order of data packets, and whether the data packets can reliably arrive when transmitting data. This service mode is called "best effort", that is, the network will make the greatest effort 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 network, a train communication network topology structure needs to be designed to guarantee the normal transmission of data when the network fluctuates and is congested, and to avoid the loss of critical data. SUMMARY

[0004] The present application proposes a train communication network topology structure and data transmission method based on ECN and ETBN to solve at least one of the technical problems in the background.

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

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

[0007] The first ETBN, the second ETBN, the third ETBN and the fourth ETBN are arranged at the backbone network head car of the train, the first ETBN and the second ETBN are arranged at the first car of the backbone network head car, and the third ETBN and the fourth ETBN are arranged at the last car of the backbone network head car; the first ETBN is connected with the second ETBN, the first ETBN is connected with the first ECN and the third ECN of the first car, and the second ETBN is connected with the second ECN and the fourth ECN of the first car; the third ETBN is connected with the fourth ETBN, the third ETBN is connected with the first ECN and the third ECN of the last car, and the fourth ETBN is connected with 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 car in the train form a first ECN network layer, and the third ECN and the fourth ECN of each car 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.

[0009] Further, the train communication network topology 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 with the third ETBN.

[0011] Further, the clock priority between the first ETBN and the third ETBN of the adjacent train is synchronized.

[0012] Further, the VRRP protocol is run between the first ETBN and the second ETBN, and the VRRP protocol is run between the third ETBN and the fourth ETBN.

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

[0014] If the train is a heavy train, the ETBN network layer is used to determine whether to start the ETBN located at the heavy end of the train based on the obtained port state of the train, and the heavy end of the train is used to represent one end of the train connected with the adjacent train.

[0015] Further, if the ETBN at the reconnection end of the train is started, the ETBN at the reconnection 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 state of the ETBN at the other end.

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

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

[0018] To achieve the above-mentioned purpose, according to another aspect of the present application, a data transmission method is provided, which is applied to the above-mentioned train communication network topology based on ECN and ETBN, comprising:

[0019] The ETBN network layer obtains train data sent by a terminal device;

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

[0021] The present application has the following beneficial effects: by setting the ETBN network layer in the ECN network layer, a more balanced and optimized network topology result is formed, the delay of data transmission is reduced, and the overall performance of the network is improved. Moreover, two ETBNs that are redundant to each other are respectively arranged in the first car and the last car, so that the reliability of data transmission is ensured. In addition, by removing the ETB bus inside the car, the use of the train-level bus and the repeater is reduced, the wiring is simplified, and the cost and the failure point are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor. In the drawings:

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

[0024] Figure 2 is a flowchart of a data transmission method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0025] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application, so that those skilled in the art can better understand the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0026] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0027] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device containing a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0028] As described in the background, the conventional train communication network topology cannot meet the real-time and deterministic requirements of rail transit communication network. And the traditional ETBN topology connection method usually depends on the train level bus (ETB) throughout the entire train. This design requires each car to be connected through the ETB bus, and the data transmission between cars needs to rely on repeaters. In this way, not only the wiring complexity and cost are increased, but also more failure points are caused.

[0029] Based on this, the present application provides a train communication network topology and data transmission method based on ECN network and ETBN network. As shown in Figure 1 The train communication network topology based on ECN network and ETBN network provided by the embodiments of the present application includes the following contents:

[0030] The first ECN, the second ECN, the third ECN and the fourth ECN are arranged in each car of the train, the first ECN is connected with the second ECN and the third ECN respectively, and the third ECN is connected with the fourth ECN;

[0031] The first ETBN, the second ETBN, the third ETBN and the fourth ETBN are arranged in the backbone head car of the train, the first ETBN and the second ETBN are arranged in the first car of the backbone head car, and the third ETBN and the fourth ETBN are arranged in the last car of the backbone head car; the first ETBN is connected with the second ETBN, the first ETBN is connected with the first ECN and the third ECN of the first car, and the second ETBN is connected with the second ECN and the fourth ECN of the first car; the third ETBN is connected with the fourth ETBN, the third ETBN is connected with the first ECN and the third ECN of the last car, and the fourth ETBN is connected with 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 car in the train form a first ECN network layer, and the third ECN and the fourth ECN of each car 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.

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

[0034] In some embodiments, the ECN network layer adopts a ring topology redundancy, and if any ECN on the transmission path fails, a new transmission path is determined through a 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 solutions of the present application, and in fact the four ECNs of each car can be the same or different, which can be set according to the actual situation. In actual application, the ECN in the car can be named according to the car number. For example, as shown in Figure 1For example, the first ECN and the third ECN in the first car can be collectively represented by ECN11, and the third ECN and the fourth ECN in the first car can be collectively represented by ECN12. Similarly, the first ECN and the third ECN in the eighth car can be collectively represented by ECN81, and the third ECN and the fourth ECN in the eighth car can be collectively represented by ECN82. The naming of ETBN in the present application is similar, and will not be described here. The specific naming can be set according to the actual situation.

[0036] In this way, by setting the ETBN network layer in the ECN network layer, a more balanced and optimized network topology result is formed, the delay of data transmission is reduced, and the overall performance of the network is improved. Moreover, two ETBNs are respectively arranged in the first car and the last car, which are redundant to each other, thereby ensuring the reliability of data transmission. In addition, by removing the ETB bus inside the car, the use of train-level bus 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 can limit the ingress frame rate and the egress frame rate from the marshalling network or the direct terminal device.

[0038] Specifically, the ETBN can limit the data frame rate entering from the marshalling network, and can also limit the data frame rate sent from the direct terminal device to the network. By setting the speed limit threshold, it can prevent too much data from flowing into the network and avoid network congestion. When the network traffic exceeds the set threshold, the ETBN will preferentially limit the transmission of low-priority messages to ensure that high-priority data can be transmitted preferentially.

[0039] In some embodiments, as shown in Figure 1 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, as shown in Figure 1As shown in the diagram for vehicle A, vehicle A's first and third ETBNs process data for the first logical link, while its second and fourth ETBNs process data for the second logical link. The ETB discovers and manages link groups in the network via TTDP HELLO frames, ensuring the availability of logical links.

[0041] It is understandable that both the first and second logical lines are ETB lines. They support five data types: monitoring data, process data, message data, stream data, and best-effort data. Different data types correspond to different priorities; for example, best-effort data has a minimum priority of 0 or 1.

[0042] In this way, two redundant logical links are formed through the ETBN of the first and last carriages. 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, such as Figure 1 As shown, different types of links are used to connect different devices. Specifically, Figure 1 Link A, or the first logical link, is the connection link between trains, used for data transmission between the train and the outside world. Link B, or the second logical link, is similar to link A, also used for data transmission between trains and the outside world, and links A and B are redundant. Link C is the connection link between the ETBN and the first ECN network layer. Since the ETBN is essentially a gateway device, it acts as a terminal device in the ECN network layer; therefore, link C is also called the connection link between the terminal device and the first ECN network layer. Link D is similar to link C, connecting the ETBN and the second ECN network layer, and is redundant with link C. Link E is the connection line between ECNs, actually a connection between Ethernet switches, belonging to the train's internal bus.

[0044] As shown above, links A and B are redundant, and links C and D are redundant. In these redundant links, if one fails, the other redundant link can immediately take over, ensuring uninterrupted data transmission and improving data transmission stability.

[0045] In some embodiments, a Virtual Router Redundancy Protocol (VRRP) is used between the first ETBN and the second ETBN in the first carriage, and between the third ETBN and the fourth ETBN in the last carriage.

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

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

[0048] The TSN is a set of protocol standards developed by the IEEE 802.1 TSN task group, which defines a time-sensitive mechanism for Ethernet data transmission. The transmission performance of service traffic in the Ethernet is ensured through mechanisms such as traffic packet priority forwarding, scheduling mechanism cleaning of the line, and bandwidth reservation. The TSN adds determinism and reliability to the standard Ethernet to ensure that the Ethernet can provide a stable and consistent service level for the transmission of critical data. The real-time performance of the TSN is mainly realized through the IEEE 8-2.1Qbv function. The difference is that the traditional Ethernet IEEE 802.1Qbu+IEEE 802.3br uses a preemption MAC to transmit high real-time data, and the IEEE 802.1Qbv uses a TimeAware Shaper to provide a dedicated time channel for high real-time data, while other non-real-time data is transmitted in a Best Effort manner. The implementation principle is that in the entire process of end-to-end data packet transmission, the TSN network optimizes the data packet for each key protocol / control information / data flow on the entire network, accurately defines the priority of the data packet in each forwarding process, and pre-arranges the priority and specifies the channel for all point-to-point paths to ensure the real-time performance and accuracy of critical data.

[0049] Specifically, the ETBN and the ECN supporting the TSN protocol realize time synchronization of each device in the network through the IEEE 802.1AS time synchronization protocol.

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

[0051] Specifically, taking the topology structure shown in Figure 1 For example, the ECN (first ECN, second ECN, third ECN and fourth ECN) of the first train is set as the highest priority (127) as the predetermined master clock, and the priority of the ECN (first ECN, second ECN, third ECN and fourth ECN) of the eighth train is set as 128 as the standby master clock. The clock priority of the ECN of the other cars is set as 246 as a normal clock, and the clock of the car is synchronized with the master clock. The clock priority of the subsystem is set as 255, and is fixed as a slave clock.

[0052] It can be understood that for the data transmitted in the communication network of the train, it is more conducive to the transmission of the data under the same time standard, especially the data transmitted based on the time-based TSN protocol. The clock synchronization of the ECN can better realize the transmission of the above-mentioned data in the whole train. At the same time, there is clock redundancy between the predetermined master clock and the standby master clock, which further guarantees the clock synchronization of the train communication network, thereby guaranteeing the timely and stable transmission of important train data.

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

[0054] For example, as shown in Figure 1 The network topology structure of the adjacent train is consistent, the first ETBN of one train is connected with the third ETBN of another train, and still forms two first logical links (also referred to as ETB A path) and second logical links (also referred to as ETB B path) which are redundant to each other.

[0055] In some embodiments, the first ETBN and the third ETBN of the adjacent train are connected.

[0056] The TTDP protocol includes a TTDP HELLO protocol and a TTDP TOPO protocol. Specifically, the TTDP HELLO frame is used to realize the acquisition of device information of the adjacent ETBN and the management of the link state, and the TTDP TOPO frame can be sent to all ETBNs to acquire the device information of all ETBNs, and form a network index table of the multiple-unit network.

[0057] In some embodiments, the clock priority of the first ETBN and the third ETBN of the adjacent train is synchronized.

[0058] Specifically, the clock priority of the ETBN of the adjacent train is uniformly set as 247 to achieve the uniform clock priority of the adjacent train. In the case of train reconnection (i.e., multiple trains are connected to each other), since the ECN clock priority of the first train 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 (also referred to as time synchronization) the clock priority with the ETBN of the adjacent train, so that the clock priority of the entire network is synchronized. Figure 1 For example, the time priority of the third ETBN of the A train and the first ETBN of the B train is synchronized, but the ETBN of the adjacent train is not time synchronized with the ECN, because the ECN is mainly used for data transmission within the vehicle, and the ETBN is responsible for train-level data transmission, and the time synchronization requirements and mechanisms of the two are different. In addition, the traffic scheduling of the ETBN depends on the time synchronized by the gPTP, which is the precise time synchronized by the 802.1AS protocol, to ensure that the data packets are transmitted within a predetermined time window, thereby improving the real-time performance and determinacy of data transmission.

[0059] In some embodiments, the device ports of the ECNs (such as the first ECN, the second ECN, the third ECN, and the fourth ECN) arranged in the train are enabled for DSCP and QoS mapping.

[0060] Specifically, the ECNs in the train distinguish the priorities of different traffics by DSCP. The ECNs map the traffics to different priority queues according to different DSCP values, and optimize the processing order of the data packets by configuring a scheduling table. The data packets with higher priority are processed preferentially to ensure that the data streams with higher delay requirements are not delayed in transmission.

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

[0062] The scheduling table includes a scheduling period, a queue switch state of a gating table item, and a duration of the gating table item. The scheduling period determines the period of time when the device processes different queues, for example, the configuration of polling or time slice. The queue switch state of the gating table item is used to manage the opening or closing state of the queue to prevent network congestion caused by excessive traffic backlog. The duration of the gating table item is related to the queue switch state of the gating table item, and the duration determines whether certain queues can continuously receive or send data packets, thereby optimizing the processing of the traffic.

[0063] In some embodiments, ETBN configures an 802.1Qbv time-aware (gated) shaper to adjust the transmission time and bandwidth of data frames based on the priority in the VLAN tag, ensuring that high-priority data receives more transmission resources. Simultaneously, by configuring IEEE 802.1Qci, it can limit the ingress and egress frame rates from the aggregation network or directly connected terminal devices, thereby controlling network traffic and ensuring that traffic of different service categories receives 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 activated;

[0065] If the train is a coupled train, the ETBN network layer is used to determine whether to activate the ETBN located 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 characterize 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. Data communication within the single-unit train is completed through the vehicle-level ECN network layer.

[0067] When the train is a double-unit train, Figure 1 Taking the illustrated topology as an example, the coupled train includes car A and car B. At the connection point between car A and car B, car A's third ETBN belongs to the coupled end ETBN of car A, and car B's first ETBN belongs to the coupled end ETBN of car B. When data transmission is required, car A's third ETBN and car B's first ETBN each check their own port status (i.e., whether a valid physical connection exists) to determine whether they are activated. If the port is in the link-up state, indicating a valid physical connection, car A's third ETBN and car B's first ETBN are activated, forming the ETBN network layer, and begin executing train-level data transmission tasks to ensure that data between different train sets can be transmitted correctly and efficiently. Simultaneously, data within each train carriage is still transmitted through the ECN network layer.

[0068] In some embodiments, if the ETBN at the train coupling end is activated, the ETBN at the coupling 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.

[0069] Specifically, when the number of reconnected trains is greater than 2, the activation rule of the ETBN network layer is still applicable, as described above. In addition, the activated ETBN obtains the activation state of the ETBN at the other end of the train, and if the ETBN at the other end is also activated, the two ETBNs can share train-level information. The ETBN at the reconnected end sends train-level information to the ETBN at the other end, so that more coordinated data transmission can be achieved between multiple consists of the reconnected train, further enhancing the reliability and efficiency of the entire communication network. For example, with Figure 1 as an example, assuming Figure 1 that the number of reconnected trains in the train is greater than 2, in the case of the third ETBN of car A being activated, the third ETBN obtains the activation state of the first ETBN of car A, and if the first ETBN is activated, the third ETBN and the first ETBN of car A share train-level information.

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

[0071] In addition, the ECN and ETBN in the topology structure provided by the present application support the TSN protocol, and through the priority division and scheduling mechanism of the TSN technology, real-time control type data is ensured to be transmitted preferentially, and the real-time performance of data transmission is improved. Moreover, through the time synchronization, data scheduling, network configuration and other mechanisms of TSN, a nanosecond-level deterministic service is provided, and the complexity of the entire communication network is reduced.

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

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

[0074] The train data carries a VLAN tag. For example, taking the train data as an ETBN packet, the ETBN enters the port carrying a VLAN tag. The priority field (IEEE 802.1Q VLAN priority field) in the VLAN tag is defined as 3 bits, representing 0-7, and the larger the number, the higher the priority. Different types of traffic data correspond to different priorities, which are defined as follows:

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

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

[0077] TRDP process data without TSN support: priority 3;

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

[0079] High-priority management protocol data (such as PTP synchronization messages, 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 table entries, the transmission of data of different priorities in a specific time window is controlled. For example, the duration of the gating table entry with high priority is set to be longer, so as to guarantee that the data with high priority has more transmission time and bandwidth. Wherein, 802.1Qbv is part of the TSN standard, which is used for time-aware shaping.

[0082] In this way, the priority division and queue management ensure that the data packets are sorted by priority, and the time-aware shaper further ensures that the high-priority data is transmitted preferentially in a specific time window. This comprehensive mechanism effectively guarantees the real-time performance and reliability of critical data, and meets the strict requirements of the rail transit communication network.

[0083] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles 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 installed 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. The first ETBN, second ETBN, third ETBN and fourth ETBN are set in the first car of the backbone head car of the train. The first ETBN and second ETBN are set in the first car of the backbone head car, and the third ETBN and fourth ETBN are set in the last car of the backbone 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. 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. The fourth ETBN is connected to the second ECN and the fourth ECN of the last car. 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. The train communication network topology is divided into a first logical link and a second logical link. The first ETBN, the second ETBN, the first ECN of the first carriage, the second ECN of the first carriage, the second ECN of the last carriage, the first ECN of the last carriage, the fourth ETBN, and the third ETBN constitute the first logical link. The second logical link consists of the first ETBN, the second ETBN, the third ECN of the first carriage, the fourth ECN of the first carriage, the fourth ECN of the last carriage, the third ECN of the last carriage, the fourth ETBN, and the third ETBN.

2. The train communication network topology according to claim 1, characterized in that, The first ETBN of adjacent trains is connected to the third ETBN.

3. The train communication network topology according to claim 2, characterized in that, The clock priority is synchronized between the first ETBN and the third ETBN of the adjacent trains.

4. The train communication network topology according to claim 1, characterized in that, The first ETBN and the second ETBN operate on the VRRP protocol; the third ETBN and the fourth ETBN operate on the VRRP protocol.

5. The train communication network topology according to claim 1, characterized in that, If the train is a single-unit train, the ETBN network layer will not be activated; If the train is a coupled train, the ETBN network layer is used to determine whether to activate the ETBN located 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 characterize the end where the train is connected to the adjacent train.

6. The train communication network topology according to claim 5, characterized in that, If the ETBN at the coupled end of the train is activated, the ETBN at the coupled 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.

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

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

9. A data transmission method, characterized in that, Applied to the train communication network topology based on ECN and ETBN as described in any one of claims 1-8, comprising: The ETBN network layer acquires train data sent by the terminal device; The ETBN network layer divides the train data into different transmission queues based on the priority in the VLAN tag of the train data in order to realize the transmission of the train data.

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