Method and system for automatically determining topology of Ethernet communication network

Abstract

The method for automatically determining the topology of a 10BASE-T1S Ethernet network comprising several nodes connected to the same communication trunk comprises the following steps performed by a control node as an end node of the communication trunk:-initialization (32) by sending a topology determination initialization message to all the connected nodes, the topology determination initialization message comprises an instruction to switch to a single receive mode,-for each connection node, sending (36) a measurement activation message to the connection node and implementing (38) a method for measuring the distance between the control node and the connection node, and storing (40) the measured distance, -determining (44) a connection order of the nodes with respect to the control node as a function of the stored distances; and-sending (42) a message to all the connected nodes to stop the topology determination.

Description

Technical Field

[0001] This invention relates to a method for automatically determining the topology of a 10BASE-T1S Ethernet communication network, also known as "twisted pair Ethernet".

[0002] The present invention also relates to a device for automatically determining the topology of a 10BASE-T1S Ethernet communication network, a computer program for automatically determining the topology of a 10BASE-T1S Ethernet communication network, and a related system. Background Technology

[0003] This invention relates to the field of Ethernet communications, and more specifically, to the field of 10BASE-T1S Ethernet, for example, as defined in the IEEE (Institute of Electrical and Electronics Engineers) standard STD 802.3 cg-2019, published in February 2020, and widely used for short-range communications. The 10BASE-T1S standard, which allows communication at 10 Mbits / second, is used in automotive and industrial applications, and particularly for electrical systems connecting multiple electrical devices.

[0004] In electrical systems, this allows for the acquisition of intelligent switching devices, each of which has communication capabilities and forms a communication node in a communication network, also simply referred to as a node.

[0005] In a 10BASE-T1S Ethernet network, communication nodes are connected to a common communication trunk (or bus) in a multipoint topology (referred to as a "multipoint network topology"). The communication nodes are electrically connected in parallel to the common communication trunk (hereinafter referred to as the "trunk" or "common trunk"). This topology requires methods to avoid collisions between data packets sent by various nodes connected to the same common communication trunk, which could lead to data loss. IEEE standard Std 802.3 cg-2019 describes a collision avoidance method called PLCA (Physical Layer Collision Avoidance). A method for identifying communication nodes has been described in patent application EP 4135268 A1, which allows transmission cycles to be allocated to each node and thus avoids any collisions.

[0006] Furthermore, in the aforementioned types of communication networks, it is sometimes necessary to know the network topology, especially the connection sequence for connecting communication nodes to the common trunk and the distance between nodes.

[0007] The term "connection sequence" refers to the spatial order of physical connections to a common trunk line.

[0008] The number of nodes and the order in which they are connected may change, especially during the operation of electrical equipment used for installing new electrical installations or for repairing or maintaining electrical systems. In practice, communication nodes are often added or removed in various applications.

[0009] One of the features proposed by the Open Systems Alliance TC14 committee uses a method for specifying network topology discovery by measuring the distance on the physical link between two communication nodes, where the method is implemented on a T1S transceiver at each communication node. This distance measurement method is implemented by each communication node at the physical layer, or “PHY layer,” Level 1 of the OSI (Open Systems Interconnection) model, and will be referred to below as the method for measuring the distance between two communication nodes connected to the same trunk, or simply the measurement method. The distance between two communication nodes is understood as the length of the cable cabling between the nodes, in length, for example, in centimeters. However, the standard does not define a method for controlling various nodes to implement the measurement method, leaving the topology of the network, including multiple communication nodes connected to the same common trunk, to be determined automatically. Summary of the Invention

[0010] The purpose of this invention is to overcome this drawback and address the need for automatically determining the topology of the aforementioned type of communication network.

[0011] Therefore, the object of the present invention is a method for automatically determining the topology of a 10BASE-T1S Ethernet communication network, the 10BASE-T1S Ethernet communication network including multiple nodes connected to the same communication trunk, the multiple nodes respectively including a first end node connected to a first end of the trunk and a second end node connected to a second end of the trunk, the method including the following steps implemented by a control node of the first end node and the second end node:

[0012] - Initialization is performed by sending a topology determination initialization message to all connected nodes, wherein the message includes an instruction to switch to single receive mode;

[0013] - For each of the connection nodes except the control node, perform the following steps in sequence:

[0014] o sends a measurement activation message to the connection node;

[0015] o Implement a method for measuring the distance between the control node and the connection node, and store the measured distance between the control node and the connection node;

[0016] - The connection order of nodes relative to the control node is determined based on the storage distance;

[0017] - Send a message to all connected nodes to stop determining the topology, wherein the stop message includes instructions to switch to send / receive mode.

[0018] Advantageously, the proposed method allows for the coordination of communication nodes on a common trunk line to perform distance measurements in node pairs and infer the network topology from them. This proposed method for automatically determining the topology of a communication network allows for the derivation of the connection order of communication nodes on the common trunk line.

[0019] According to other advantageous aspects of the invention, the method for automatically determining network topology includes one or more of the following features, either individually or in any technically possible combination.

[0020] The method also includes the step of a control node broadcasting a network topology report to one or more remote devices connected via a network gateway device connected to the control node, the topology report including an ordered list of nodes according to a determined connection order, wherein each node is identified by a unique identifier.

[0021] Determining the connection order of nodes involves sorting the stored measured distances in ascending order.

[0022] The initialization step occurs after the control node receives a message indicating that at least one node is connected to or disconnected from the trunk.

[0023] The initialization step occurs after the control node receives the topology determination request.

[0024] The method further includes: a step of checking the distance condition between successive nodes according to the determined connection order; and a step of issuing an alarm message when the distance between successive nodes is less than a minimum distance threshold.

[0025] After receiving the topology determination initialization message, each different connected node of the control node starts a timer, and after receiving a stop topology determination message, or when the timer reaches a predetermined duration threshold, each connected node returns to send and receive mode.

[0026] The present invention also relates to an apparatus for automatically determining the topology of a 10BASE-T1S Ethernet communication network, the 10BASE-T1S Ethernet communication network including multiple nodes connected to the same communication trunk, the multiple nodes respectively including a first end node connected to a first end of the trunk and a second end node connected to a second end of the trunk, the automatic topology determination apparatus being a control node among the first end node and the second end node, and configured to perform modules for:

[0027] - Initialization is performed by sending a topology determination initialization message to all connected nodes, wherein the message includes an instruction to switch to single receive mode;

[0028] - For each of the connection nodes except the control node, execute the following in sequence:

[0029] o sends a measurement activation message to the connection node;

[0030] o Implement a method for measuring the distance between the control node and the connection node, and store the measured distance between the control node and the connection node;

[0031] - The connection order of nodes relative to the control node is determined based on the storage distance;

[0032] - Send a message to all connected nodes to stop determining the topology, wherein the stop message includes instructions to switch to send / receive mode.

[0033] The present invention also relates to a system for automatically determining the topology of a 10BASE-T1S Ethernet communication network, the 10BASE-T1S Ethernet communication network including multiple nodes connected to the same communication trunk, the multiple nodes respectively including a first end node connected to a first end of the trunk and a second end node connected to a second end of the trunk, the system including a control node in the first end node and the second end node, the control node being configured to implement the method for automatically determining the network topology as described above, each different connection node of the control node being configured to switch to a single receive mode and start a timer after receiving a topology determination initialization message, and to switch to a transmit and receive mode after receiving a stop topology determination message, or when the timer reaches a predetermined duration threshold.

[0034] The present invention also relates to a computer program comprising software instructions that, when executed by a programmable electronic device, implement the method for automatically determining network topology as defined above. Attached Figure Description

[0035] The invention will become more apparent from the following description, which is illustrated only by non-limiting examples and with reference to the accompanying drawings, wherein:

[0036] Figure 1 It is a schematic representation of a 10BASE-T1S Ethernet communication network that includes multiple nodes in an electrical system;

[0037] Figure 2 yes Figure 1 A summary diagram of the main blocks of the communication node;

[0038] Figure 3 This is a flowchart of the main steps of a method for automatically determining the topology of a network according to one embodiment;

[0039] Figure 4 The diagram illustrates two scenarios where the measured distance between nodes does not meet the minimum distance threshold condition. Detailed Implementation

[0040] The application of the invention in an electrical system integrated into an electrical cabinet will be described in more detail below. The electrical system includes multiple motor starters mounted side by side in the electrical cabinet, each motor starter including a communication interface that allows it to connect to a 10Base-T1S Ethernet.

[0041] Of course, the present invention is not limited to this application.

[0042] Figure 1 An electrical system 2 is schematically shown that includes a wired communication network 4 of type 10Base-T1S Ethernet with a multidrop network topology.

[0043] Communication network 4 includes an Ethernet communication backbone (or bus). Figure 1 The attached figure shows reference numeral 6, and multiple communication nodes 8 connected to the trunk line 6, which will also be referred to as nodes in the following text, and are numbered as node N1, node N2, ..., node N... n Trunk 6 is formed by a single pair of twisted cables that form a linear trunk according to the 10Base-T1S Ethernet standard.

[0044] The communication node is configured to be in a first mode, known as "single receive mode", in which it cannot send any messages, or in a second mode, known as "send / receive mode", in which it can send messages without any restrictions.

[0045] In this application example, at least some of the communication nodes 8 are motor starters that provide a 10Base-T1S Ethernet communication interface. Items of electrical device 10 (motors in this example) are connected to the respective starters via cables.

[0046] More generally, in one embodiment, each node 8 is an electrical device, such as a switch, contactor, circuit breaker, any type of electrical protection device, or even an electrical sensor.

[0047] However, it should be understood that other embodiments are conceivable.

[0048] The multiple nodes 8 connected to the trunk line 6 include end nodes, which are the first end nodes connected to the first end of the trunk line ( Figure 1 In the example, node N1) and the second end node connected to the second end of trunk line 6 ( Figure 1 Node N in the example n In other words, an end node is the first and last node connected to trunk 6, and each end node has a single neighbor node, which is the successor or predecessor of the connected nodes.

[0049] One of the end nodes, in Figure 1 In the example, node N1 is a network head node or switch connected to Ethernet network device 12 via a physical link (preferably wired), such as a switch or router, which is preferably a network gateway device that allows communication with other subnetworks. This end node N1 is a control node, advantageously configured to implement methods for automatically determining the network topology.

[0050] In one embodiment, node N1 is a switch comprising a plurality of 10BASE-T1S ports, configured to implement control node functionality on each of the 10BASE-T1S ports.

[0051] In one embodiment, node N1 is connected to network device 12 via a 100Base-Tx Ethernet link.

[0052] Specifically, network device 12 allows bidirectional communication with other connected remote devices, such as SCADA (Supervisory Control and Data Acquisition) monitoring and control device 14. Device 14 is operated by an operator or accessible by a remote operator terminal providing a human-machine interface for performing operational checks on the monitored electrical system.

[0053] like Figure 2 As shown, each node 8 includes a module 16, which is configured to implement the main functions of the associated electrical equipment in the electrical system 2.

[0054] Furthermore, each communication node includes a processor 18 and an electronic memory 20, forming a programmable electronic device configured to execute software instructions. Specifically, the control node is configured to execute software instructions for implementing a method for automatically determining the topology of the communication network, as described in detail below.

[0055] Methods for automatically determining network topology are implemented, for example, in the form of software modules or blocks forming a computer program or in the form of programmable logic components, such as FPGAs (Field-Programmable Gate Arrays), or even integrated circuits, such as ASICs (Application-Specific Integrated Circuits). The computer program may also be stored on a computer-readable medium (not shown). A computer-readable medium is, for example, a medium capable of storing electronic instructions and capable of being connected to a bus of a computer system. As examples, readable media are optical discs, magneto-optical discs, ROM, RAM, any type of non-volatile memory (e.g., flash memory or NVRAM), or magnetic boards.

[0056] Furthermore, each node 8 includes a network interface 22, specifically an Ethernet connector, configured to implement IEEE 802.3 cg-2019 protocol functions at the physical level, particularly PLAC collision avoidance, and methods for measuring the distance between two nodes as specified in Release 1 of the "OPEN Alliance 10BASE-T1S Topology Discovery" specification published on March 21, 2023. The network interface 22 implements data transmission and reception functions according to the IEEE 802.3 cg-2019 standard.

[0057] The method for automatically determining the network topology is implemented upon request, for example, after the control node receives a topology determination request from the network device 12, or when the control node receives a message indicating that at least one node 8 is connected or disconnected from the trunk 6.

[0058] The method for automatically determining the network topology is implemented by a control node, which determines the topology, specifically the relationship between each node 8 and a selected control node N among multiple nodes connected to the trunk 6. c The connection order, and the selected control node N c It also serves as a reference node for measuring the distance between nodes in a pair of nodes.

[0059] To distinguish the various nodes 8, each node has a unique identifier, such as a physical unique identifier or a UID (unique identifier), which is, for example, a hardware identifier of the node, such as its physical address (also known as a MAC (media access control) address) or a product unique identifier provided during manufacturing.

[0060] To ensure the correct determination of the topology, the selected control node N c It is one of the end nodes, for example, the first end node N1 or the second end node N. n .

[0061] Preferably, the selected control node is an end node connected to the network device 12.

[0062] The control node provides control (or coordination) functions for connecting to other nodes on the common trunk 6, for automatically determining the network topology, and provides a reference node function for distance measurement according to the measurement method. Therefore, automatically determining the network topology allows for obtaining the connection order of nodes on trunk 6 and the distances between successively connected nodes.

[0063] According to the "OPEN Alliance 10BASE-T1S Topology Discovery" specification, when all other nodes in the network are in single-receive mode (or limited to receive), two-node N can be executed. Aand N B The distance between nodes is measured, where all transmissions on the trunk line are blocked to avoid any interference and disruption. In other words, the distance between nodes N is measured using a specific method. A and N B While considering the distance between them, the network and node N A and N B The other nodes are silent (i.e., they do not send any messages).

[0064] Figure 3 This is a schematic diagram of the main steps of a method for automatically determining the topology of a 10BASE-T1S Ethernet communication network according to one embodiment.

[0065] Step 100 is controlled by node N c The implementation is carried out, and step 200 is carried out by other nodes connected to trunk 6.

[0066] In many applications, the control node is a gateway node or a T1S / 100Base-Tx switch.

[0067] The method includes control node N c The process involves several steps, which are initiated by activating the determination of the 30-communication network topology.

[0068] Activation 30 occurs, for example, after receiving a request to determine the topology on the communication network, or after receiving a message indicating the connection or disconnection of one or more communication nodes in the network.

[0069] According to one embodiment, the connection or disconnection of one or more communication nodes in the network causes a reallocation of the PLCA identifier to the connected node 8, for example, by means of the method described in EP 4135268 A1. The reallocated PLCA identifier is sent to all nodes in the network via a broadcast message.

[0070] As a variation or supplement, activation 30 is repeated at regular time intervals.

[0071] Following activation step 30 is step 32, which involves the control node sending a topology determination initialization message, such as a "broadcast message," to all other connected nodes. This initialization message is received by all nodes connected to the trunk and includes an instruction to switch to single-receive mode. Then, any transmission from one of these other nodes is blocked.

[0072] After receiving the topology determination initialization message sent by the control node, each of the connected nodes switches to single receive mode (step 33) and starts (step 35) a timer, which is monitored independently of other connected nodes.

[0073] Control Node N c Implement step 34, select node N to connect to the trunk line. m This is referred to as the node under test, and then in step 36, the data is sent to the node under test N. m Send a measurement activation message.

[0074] Each node is identified by a unique identifier, which is its physical address or a PLCA identifier determined according to the method described in patent application EP4135268 A1.

[0075] In one embodiment, the subsequent node N is selected according to a predetermined path order, for example, in ascending or descending order of identifiers. m .

[0076] Alternatively, the subsequent node N can be selected in a random order. m .

[0077] Next, following the commands from the control node, the measurement method is implemented (step 38), where control node N... c It is a "reference node" used for measurement, and node N m It is the "node under test". In other words, during step 38, the control node N... c Perform measurement methods to determine control node N. c With the selected node N m The distance between them.

[0078] The 36 steps of sending and the 38 steps of implementing the measurement method are executed sequentially, that is, one after another. For each node to be measured, the 36 steps of sending and the 38 steps of implementing the measurement method are repeated one after another.

[0079] Node N m Configured to respond to a signal from control node N according to a measurement method when it is in "single / receive" mode. c Use the message to send messages.

[0080] Control node N determined by implementing distance measurement method c With node N m Dist(N) between c , N m The data is stored by the control node in storage step 40, for example, in the memory 20 of the control node.

[0081] Steps 34 to 40 are implemented for each node connected to trunk 6.

[0082] After measuring control node N cAfter determining the distance between each of the other nodes connected to trunk line 6, control node N... c Then, in step 42, a message is sent to all connected nodes to stop determining the topology, for example by means of a "broadcast" type message, including an instruction to switch to "send / receive" communication mode, preferably to achieve PLCA conflict avoidance.

[0083] Each connection node N k Monitor (step 37) the value of the timer started after receiving the topology determination initialization message, and if the value of the timer reaches or exceeds a predetermined duration threshold, while node N... k In single-receiver mode, node N k Switch to send / receive mode (step 39).

[0084] The predetermined duration threshold is, for example, on the order of 1 second, wherein the duration is compatible with the expected duration for performing the steps used to determine the network topology.

[0085] Advantageously, by means of an autonomous monitoring timer for each communication node, even in the event of loss (or non-reception) of the stop topology determination message sent by the control node in step 42, each communication node returns to transmit / receive mode when a predetermined duration threshold is reached. Therefore, this prevents the communication node from remaining trapped in a "single / receive" mode if it does not receive the stop topology determination message sent by the control node in step 42.

[0086] When the distance measurement between the control node and every other node has been successfully completed, the control node N... c Step 44 involves determining the connection order of nodes on the trunk relative to the control node based on the stored measured distances.

[0087] According to one embodiment, step 44 involves sorting the stored measured distances in ascending order of distance. An ordered list of communication nodes, identified by unique identifiers of the communication nodes, is then obtained, providing the connection order of the nodes on the trunk, starting with the control node. The control node is added to the first position in this list.

[0088] The steps of sending message 42 to stop determining the topology and determining the connection order of nodes on the trunk line (step 44) can be performed in any order.

[0089] Since the control node is one of the end nodes, the network topology is completely determined.

[0090] It can also calculate the distance between any two nodes in a chosen pair of nodes, especially the distance between successive nodes.

[0091] In fact, for two separate nodes NA and N B The described method provides each of these nodes to the control node N. c The distances are Dist(N) and Dist(N) respectively. c , N A ) and Dist(N c , N B ).

[0092] Then, N A With N B The distance between them is simply equal to the corresponding distance Dist(N) c , N A ) and Dist(N c , N B The difference between them, taken as the absolute value:

[0093] D AB =Abs(Dist(N c , N A )- Dist(N c , N B ))

[0094] Preferably, the control node further implements step 46, checking the distance conditions between successive nodes according to the connection order of the nodes indicated by the ascending order of the measured distances.

[0095] Step 46 involves calculating the distance between nodes in each pair of successive nodes and comparing this distance with a minimum distance threshold D. min Compare them.

[0096] In practice, methods for measuring the distance between two nodes allow the distance between the two nodes to be determined with an error tolerance (or precision) E. Considering this error tolerance E, if the distance determined between a pair of successive nodes is less than the minimum distance D... min Therefore, it is considered impossible to guarantee the connection order of these two nodes on the trunk line with sufficient certainty.

[0097] In other words, calculate the difference between successive items in the ordered distance list, and then compare each of these differences with the minimum distance threshold D. min Compare them.

[0098] According to the "OPEN Alliance 10BASE-T1S Topology Discovery" specification, the error tolerance E is typically on the order of 15 cm. Minimum distance threshold D... min It can be selected as, for example, twice the value of the error tolerance E, i.e., 30 cm.

[0099] The minimum distance threshold D minIt can vary as a function of application-specific design values, particularly depending on the value of the error tolerance E.

[0100] If the distance between two successive nodes is less than the minimum distance threshold D min If an error is suspected, then the possibility of an error is considered. In this case, step 48, following step 46 of checking the distance conditions, is step 48 of issuing an alarm message. For example, such an alarm, issued on a human-machine interface for an operator (e.g., an installer), notifies the operator that the physical wiring should be checked.

[0101] When an alarm message is issued, this indicates that the two nodes are considered to be within a minimum distance threshold D. min At a distance of [distance], this could be due to wiring errors, measurement errors, or even, in certain cases, incorrect selection of control nodes, leading to an incorrect determination of the topology.

[0102] The method further includes step 50, which involves the control node broadcasting a network topology report to one or more remote devices, such as those connected to the network device 12 forming the communication gateway. For example, the topology report includes an ordered list of connected nodes according to the connection order determined in step 44, wherein each node is identified by its unique identifier.

[0103] Optionally, the topology report may also include the distance between successive nodes.

[0104] Figure 4 Two examples of topologies are shown, in which an alarm is issued after checking step 46.

[0105] exist Figure 4 In the first example shown above, two adjacent nodes N A and N B Within the minimum distance threshold D min Distance D AB Therefore, this, for example, indicates a wiring error.

[0106] exist Figure 4 In the second example shown below, if the selected control node N c If it is not one of the end nodes of the common trunk line 6, then the corresponding distance Dist(N) c , N A ) and Dist(N c , N B They are very close, so their difference is less than the minimum distance threshold D. min In fact, the corresponding node N A and N B Connected to control node N c Both sides. Then the wiring must be modified and the topology determination method restarted.

Claims

1. A method for automatically determining the topology of a 10BASE-T1S Ethernet communication network (4), the 10BASE-T1S Ethernet communication network (4) comprising a plurality of nodes (8) connected to the same communication trunk (6), the plurality of nodes (8) respectively comprising a first end node connected to a first end of the trunk (6) and a second end node connected to a second end of the trunk (6), the method being characterized in that it comprises a first end node (N1) and a second end node (N2) connected to a second end of the trunk (6), the method comprising a first end node (N1) and a second end node (N2) connected to a second end of the trunk (6), the method being characterized in that the topology is determined by the first end node (N1) and the second end node (N2) connected to the ... n The control node (N) in ) c The following steps are to be implemented: - Initialize (32) by sending a topology determination initialization message to all connected nodes (8), the message including an instruction to switch to single receive mode; - For each of the connection nodes (8) other than the control node, perform the following steps sequentially: o sends a measurement activation message (36) to the connection node (8); o Implement (38) a method for measuring the distance between the control node and the connection node (8), and store (40) the measured distance between the control node and the connection node (8); - The connection order of (44) nodes relative to the control node is determined based on the stored distance; - Send a (42) message to all connected nodes (8) to stop determining the topology, the stop message including an instruction to switch to send / receive mode.

2. The method of claim 1, further comprising step (50), involving a control node broadcasting a network topology report to one or more remote devices (14) connected via a network gateway device (12) connected to the control node, the topology report comprising an ordered list of nodes (8) according to a determined connection order, wherein, Each node is identified by a unique identifier.

3. The method according to any one of claims 1 or 2, wherein, Determining the connection order of (44) nodes involves sorting the stored measured distances in ascending order.

4. The method according to any one of claims 1 to 3, wherein, The initialization step (32) occurs after the control node receives a message indicating that at least one node is connected to or disconnected from the trunk.

5. The method according to any one of claims 1 to 3, wherein, The initialization step (32) occurs after the control node receives the topology determination request.

6. The method according to any one of claims 1 to 5, further comprising: Step (46): Check the distance conditions between successive nodes according to the determined connection order; And in step (58), when the distance between successive nodes is less than the minimum distance threshold, an alarm message is issued.

7. The method according to any one of claims 1 to 6, wherein, After receiving the (33) topology determination initialization message, the control node (N) c Each different connection node (8) starts a timer (35), and after receiving a message to stop determining the topology, or when the timer reaches a predetermined duration threshold (37), each connection node (8) returns to the send and receive mode (39).

8. A computer program comprising software instructions that, when executed by a programmable electronic device, implement the method for automatically determining the topology of a network according to claims 1 to 7.

9. An apparatus for automatically determining the topology of a 10BASE-T1S Ethernet communication network, the 10BASE-T1S Ethernet communication network comprising a plurality of nodes (8) connected to the same communication trunk (6), the plurality of nodes (8) respectively comprising a first end node (N1) connected to a first end of the trunk (6) and a second end node (N2) connected to a second end of the trunk (6). n The automatic topology determination device is the control node (N) among the first end node and the second end node. c ), and is configured as an execution module to: - Initialization is performed by sending a topology determination initialization message to all connected nodes (8), the message including an instruction to switch to single receive mode; - For each of the connection nodes (8) except the control node, execute in sequence: o sends a measurement activation message to the connection node (8); o Implement a method for measuring the distance between the control node and the connection node (8), and store the measured distance between the control node and the connection node; - The connection order of nodes relative to the control node is determined based on the stored distance; - Send a message to all connected nodes to stop determining the topology, where the stop message includes instructions to switch to send / receive mode.

10. A system for automatically determining the topology of a 10BASE-T1S Ethernet communication network (4), the 10BASE-T1S Ethernet communication network (4) comprising a plurality of nodes (8) connected to the same communication trunk (6), the plurality of nodes (8) respectively comprising a first end node connected to a first end of the trunk (6) and a second end node connected to a second end of the trunk (6), the system (4) being characterized in that a control node (N) in the first end node and the second end node c The control node is configured to implement the method for automatically determining network topology according to claims 1 to 6, and after receiving the topology determination initialization message, each different connection node (8) of the control node switches to single receive mode and starts a timer, and after receiving the stop topology determination message, or when the timer reaches a predetermined duration threshold, switches to send and receive mode.

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