METHOD AND CONTROL DEVICE FOR TRANSMITTING SAFETY-RELEVANT DATA IN A MOTOR VEHICLE BY MEANS OF AN ETHERNET STANDARD

Abstract

Safety-relevant data in a motor vehicle is transmitted by means of an Ethernet standard via at least one intermediate node in an Ethernet packet. Each intermediate node receives an Ethernet packet, evaluates it, and forwards it accordingly. Provision is made for a data type for safety-relevant data to be transmitted in communication information in the Ethernet frame with the safety-relevant data, for each intermediate node to check the communication information from the data contents of the Ethernet frame in the received Ethernet packet for the presence of the data type for safety-relevant data, for each intermediate node to duplicate an Ethernet frame, which contains the data type for safety-relevant data in the communication information, at least once, and for each intermediate node to emit the duplicated Ethernet frame in a new Ethernet packet.

Claims

1. A method for transmitting safety-relevant data in a motor vehicle by means of an Ethernet standard from a transmitter via at least one intermediate node to a receiver, in which the safety-relevant data are sent from the transmitter in an Ethernet packet, the Ethernet packet having an Ethernet frame with the data content and the data content containing communication information and data, each intermediate node which receives an Ethernet packet evaluates at least a part of the communication information from the data content which is used in a first or second layer of the OSI layer model in the context of the communication organization and forwards the Ethernet packet in accordance with the evaluated communication information, and the receiver receives the Ethernet packet, evaluates the communication information from the data content and evaluates the data from the data content if, on the basis of the evaluated communication information, it is the receiver of the safety-relevant data, characterized in that in the communication information, used in the first or second layer of the OSI layer model, of the Ethernet frame a data type for safety-relevant data is transmitted with the safety-relevant data, each intermediate node checks in the received Ethernet packet the communication information used in the first or second layer of the OSI layer model from the data content of the Ethernet frame for the presence of the data type for safety-relevant data, each intermediate node duplicates an Ethernet frame, which contains the data type for safety-relevant data in the communication information used in the first or second layer of the OSI layer model, at least once, and each intermediate node sends out the duplicated Ethernet frame in a new Ethernet packet.

2. The method as claimed in claim 1, characterized in that each intermediate node duplicates an Ethernet frame, which contains the data type for safety-relevant data in the communication information, several times and sends it out in each case in a new separate Ethernet packet, the number of duplicated Ethernet frames being parameterizable.

3. The method as claimed in claim 2, characterized in that data fields, present in the Ethernet standard, of the communication information used in the first or second layer of the OSI layer model are used for the transmission or the data type for safety-relevant data, in that these are occupied with a value, not issued in the Ethernet standard, for the data type for safety-relevant data.

4. The method as claimed in claim 3, characterized in that the data fields having the destination address, the transmitter address are utilized for the Ethernet type and/or the VLAN flag as data fields of the communication information used in the first or second layer of the OSI layer model for the transmission of the data type for safety-relevant data.

5. The method as claimed in claim 4, characterized in that the data fields arranged first in the Ethernet frame are used as data fields of the communication information used in the first or second layer of the OSI layer model for the transmission of the data type for safety-relevant data.

6. The method as claimed in claim 5, characterized in that the intermediate node sends out the Ethernet packet with the duplicated Ethernet frame or the several Ethernet packets with in each case the duplicated Ethernet frame in direct sequence after the Ethernet packet received first with the Ethernet frame generated by the transmitter.

7. The method as claimed in claim 6, characterized in that the receiver of the Ethernet packet checks the correct reception of the Ethernet packet having the Ethernet frame and, in the case of a correct reception, discards possible subsequently received Ethernet packets having the same Ethernet frame when the Ethernet frame the communication information used in the first or second layer of the OSI layer model has the data type for safety-relevant data.

8. A control device having a communication unit for transmitting safety-relevant data in a motor vehicle and having a computing unit, the computing unit being configured to operate the communication unit for receiving and/or transmitting the safety-relevant data by means of an Ethernet packet in accordance with the Ethernet standard in the first and second layer of the OSI layer model, the Ethernet packet having an Ethernet frame with the data content which contains communication information and data, characterized in that the computing unit is configured to evaluate after the reception of an Ethernet packet at least a part of the communication information from the data content of the Ethernet frame which is used in a first and a second layer of the OSI layer model as part of the communication organization and to check it for the presence of the data type for safety-relevant data.

9. The control device as claimed in claim 8, characterized in that the computing unit is configured to duplicate an Ethernet frame, which contains the data type for safety-relevant data in the communication information used in the first or second layer of the OSI layer model, at least once and to send out the duplicated Ethernet frame in a new Ethernet packet.

10. The control device as claimed in claim 9, characterized in that the computing unit is configured to check the correct reception of an Ethernet packet having the Ethernet frame and, in the case of a correct reception, to discard possible subsequently received Ethernet packets having the same Ethernet frame when the Ethernet frame in the communication information used in the first or second layer of the OSI layer model has the data type for safety-relevant data.

11. The control device as claimed in claim 10, characterized in that the computing unit is configured to transmit in the communication information used in the first or second layer of the OSI layer model of an Ethernet frame of safety-relevant data also a data type for safety-relevant data.

12. A computer program product having program code means which are suitable for configuring, when executed on a computing unit of a control device having a communication unit for transmitting safety-relevant data in a motor vehicle, the computing unit being configured to operate the communication unit for receiving and/or transmitting the safety-relevant data by means of an Ethernet packet in accordance with the Ethernet standard in the first and second layer of The OSI layer model, the Ethernet packet having an Ethernet frame with the data content which contains communication information and data, characterized in that the computing unit is configured to evaluate after the reception of an Ethernet packet at least a part of the communication information from the data content of the Ethernet frame which is used in a first and a second layer of the OSI layer model as part of the communication organization and to check it for the presence of the data type for safety-relevant data; the computing unit being configured to duplicate an Ethernet frame, which contains the data type for safety-relevant data in the communication information used in the first or second layer of the OSI layer model, at least once and to send out the duplicated Ethernet frame in a new Ethernet packet the computing unit being configured to check the correct reception of an Ethernet packet having the Ethernet frame and in the case of a correct reception, to discard possible subsequently received Ethernet packets having the same Ethernet frame when the Ethernet frame is the communication information used in the first or second layer of the OSI layer module has the data type for safety-relevant data; the computing unit being configured to transmit in the communication information used in the first or second layer of the OSI layer model of an Ethernet frame of safety-relevant data also a data type for safety-relevant data.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other advantages, features and possible applications of the present invention are also obtained from the subsequent description of an illustrative embodiment and the drawings. In this context, all features described and/or pictorially represented, by themselves or in arbitrary combination, form the subject matter of the present invention also independently of its combination in the claims or their references. In the figures:

[0045] FIG. 1 shows diagrammatically the transmission of an Ethernet packet between a transmitter and a receiver according to the prior art;

[0046] FIG. 2 shows diagrammatically the typical forwarding of an Ethernet frame in the computing units of the control devices within the context of the OSI layer model in accordance with the prior art;

[0047] FIG. 3 shows the structure of an Ethernet packet according to the prior art;

[0048] FIG. 4 shows the processing of an Ethernet frame with an identifier, proposed according to the invention, of a data type for safety-relevant data along the transmission path according to a preferred embodiment of the present invention;

[0049] FIG. 5 shows a section of an Ethernet frame with the data type proposed according to the invention in different data fields according to different variants of the present invention.

[0050] FIG. 6 shows an actual illustrative embodiment for communication data of an Ethernet frame in accordance with the examples described before.

DETAILED DESCRIPTION

[0051] In FIGS. 1 to 3, the known Ethernet standard is presented with regard to the structure of the Ethernet packets and the sequence along a communication path, showing the features essential with regard to the present invention. These figures have already been described in detail before for the purpose of explanation. This description is referred to at this point.

[0052] FIG. 4 shows a transmission system 1 according to the Ethernet standard which is configured in accordance with the proposed method for transmitting safety-relevant data.

[0053] Similar to the presentation according to FIG. 2, the transmission system 1 also has a control device 2 serving as transmitter, a control device 3 serving as receiver and a control device 4 serving as intermediate node. All control devices 2, 3, 4 process the communication protocol according to the OSI model, the Ethernet standard only being implemented in the first two layers OSI 1 and OSI 2 of the layer model. Correspondingly, the transmitter 2 generates in the layer OSI 2 an Ethernet frame 5 which structurally corresponds to the Ethernet frame 58 shown in FIG. 3 and is sent out embedded into an Ethernet packet, not shown.

[0054] This Ethernet packet with the Ethernet frame 5 contains in the communication information of the Ethernet frame 5, as they are shown diagrammatically in FIGS. 5 and 6, the data type 7 (shown checked in the representation according to FIGS. 5 and 6) which have been installed into the Ethernet frame 5 by the transmitter 2. The intermediate node 4 reads the communication information 6 of the Ethernet frame 5 after the reception and filters it according to data type 7.

[0055] If there is such a data type 7 for safety-relevant data in the Ethernet frame 5, the computing unit of the intermediate node 4 duplicates the Ethernet frame to form a duplicated Ethernet frame 5′ having identical data content. Both Ethernet frames 5, 5′ are designed in preferably immediately successive Ethernet packets, not shown in the representation according to FIG. 4, in the direction of the receiver 6, the duplicated Ethernet frame 5′ being sent out preferably after the original Ethernet frame 5. Preferably, no other Ethernet packet should be sent intermediately by the intermediate node between the Ethernet data packet having the Ethernet frame 5 and the Ethernet packet having the duplicated Ethernet frame 5′.

[0056] In the representation according to FIG. 4, only one duplicated Ethernet frame 5′ is shown. According to the invention, however, there can be a single or a multiple duplication.

[0057] Correspondingly, the receiver 3 receives two Ethernet data packets, namely the first Ethernet data packet having the Ethernet frame 5 and the second Ethernet data packet having the duplicated Ethernet frame 5′. The receiver 3 checks if on entry of a data packet into the Ethernet frames 5, 5′ the data type 7 for safety-relevant data is present. If this is the case, the receiver 3 can assume that this Ethernet frame 5 will be followed by a copy as duplicated Ethernet frame 5′. If the original Ethernet frame 5 received first has already been received correctly and faultlessly, the receiver 3 discards the subsequent copy of the duplicated Ethernet frame 5′. If, in contrast, an error has occurred in the data packet of the original Ethernet frame 5 during the transmission, the receiver 3 can use the copy, sent subsequently within a very short time interval, of the duplicated Ethernet frame 5′. This creates a high redundancy de facto because no detailed enquiry of the receiver 3 at the transmitter 2 is necessary.

[0058] FIG. 5 shows the communication information 6 of an Ethernet frame 5 according to a preferred embodiment. The communication information 6 contains in each case the destination address 8, the transmitter address 9 and the Ethernet type 10. The variants A, B, C and D, shown in FIG. 5, of the communication information 6 differ in that the data type 7 for safety-relevant data is provided as identifier in the different data fields destination address 8, transmitter address 9 and Ethernet type 10, respectively. The variant A shows the data type 7 in the transmitter address 9, the variant B in the destination address 8, the variant C combined in the destination address 8 and the transmitter address 9 and the variant D in the Ethernet type 10.

[0059] FIG. 6 shows the variant D from FIG. 5 in an actual numerical example. In this context, certain values of the individual data fields destination address 8, transmitter address 9 and Ethernet type 10 and possibly VLAN tag (not shown in FIGS. 5 and 6) are reserved in accordance with the Ethernet standard. Such reserved destination addresses 8 and transmitter addresses 9 are entered by way of example as so-called MAC addresses in FIG. 6 in the representation.

[0060] The Ethernet type 10 has the hexadecimal sequence of numbers 90-05 which is not issued in accordance with the Ethernet standard. The control devices 2, 3, 4 which participate in the transmission system 1 according to the Ethernet standard in the transmission of safety-relevant information can thus filter in the data field of the Ethernet type 10 for the decimal number “09-05” in the example shown in FIG. 6 in order to activate the redundancy function in accordance with the method proposed according to the invention and activate a duplication of the Ethernet frames 5 to form one or more duplicated Ethernet frames 5′ which are fed to the receiver 3 as Ethernet packets preferably following one another directly.