Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L12/40143—Bus networks involving priority mechanisms
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/46—Interconnection of networks
  • H04L12/4604—LAN interconnection over a backbone network, e.g. Internet, Frame Relay
  • H04L12/462—LAN interconnection over a bridge based backbone
  • H04L12/4625—Single bridge functionality, e.g. connection of two networks over a single bridge
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/66—Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L43/00—Arrangements for monitoring or testing data switching networks
  • H04L43/16—Threshold monitoring
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/10—Flow control; Congestion control
  • H04L47/12—Avoiding congestion; Recovering from congestion
  • H04L47/125—Avoiding congestion; Recovering from congestion by balancing the load, e.g. traffic engineering
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L67/00—Network arrangements or protocols for supporting network services or applications
  • H04L67/01—Protocols
  • H04L67/12—Protocols specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L43/00—Arrangements for monitoring or testing data switching networks
  • H04L43/08—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
  • H04L43/0876—Network utilisation, e.g. volume of load or congestion level
  • H04L43/0894—Packet rate
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L67/00—Network arrangements or protocols for supporting network services or applications
  • H04L67/01—Protocols
  • H04L67/10—Protocols in which an application is distributed across nodes in the network
  • H04L67/1001—Protocols in which an application is distributed across nodes in the network for accessing one among a plurality of replicated servers
  • H04L67/1004—Server selection for load balancing
  • H04L67/1008—Server selection for load balancing based on parameters of servers, e.g. available memory or workload

Definitions

• This document relates to a method and a gateway of a bus. More particularly, a method and a gateway is provided for a bus comprising a plurality of segments, for load balancing of traffic load for non-cyclic messages between the different segments of the bus.
• a Controller Area Network (CAN) bus is a vehicle computer system bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles, but is also used in many other contexts.
• the load balancing is done (calculated) at design and depending on net- work structure and implemented distributed functionality it might differ from the real product. This becomes a problem for a vehicle manufacturer producing modular vehicles. It then becomes very difficult to make the correct calculations for an appropriate load balancing for all vehicles. Another thing adding to the problem is non-cyclic messages such as diagnosis, where a burst of network traffic can happen at 'any-time'.
• the CAN gateway When sending large amount of non-cyclic data such as when reading out vehicle information with remote diagnostics, downloading new software or making a performance test at a work- shop, the CAN gateway becomes 'choked' by messages and start losing CAN-frames as the reception buffer is overflown.
• CAN traffic of the bus is regulated by CAN priority and the gateway stores the messages in a buffer between the different network segments.
• One problem occurs when the load on the network segments are non-equal and the incoming messages are at a higher rate than the gateway can send out on the other side.
• the priority (arbitration) of the CAN-protocol takes care of the flow and slows down the sending frequency of the nodes.
• Bus arbitration is a procedure in bus communication that chooses between connected devices contending for control of the shared bus. The device currently in control of the bus may be termed the bus master. Devices attached to the bus may be allocated differing priority levels that will determine the choice of bus master in case of contention.
• a device not currently bus master must request control of the bus before attempting to initiate a data transfer via the bus.
• Only a bus master may initiate a normal data transfer on the bus; slave devices respond to commands issued by the current bus master by supplying data requested or accepting data sent.
• empty messages are transmitted in order to avoid congestion on a network.
• the empty messages are sent continuously with real messages and the pool/ rate is adapted based on application or message sizes. Arbitration is however not changed, instead transmission of messages is prevented or delayed.
• this objective is achieved by a method in a gateway of a bus, comprising a plurality of segments, for load balancing of traffic load for non- cyclic messages between the different segments comprised in the bus.
• the method comprises determining the respective traffic load of the segments of the bus.
• the method also comprises calculating the respective traffic load difference between the determined respective traffic load.
• the method also comprises determining the largest traffic load difference of the calculated traffic load differences.
• the method additionally comprises com- paring the determined largest traffic load difference with a threshold limit value.
• the method also comprises sending a set of messages on the segment of the bus having the lowest determined traffic load, with a frequency based on the calculated respective traffic load difference, wherein the set of messages has a priority level exceeding a first priority level but not exceeding a second priority level.
• the method further comprises iterating the method according to the previously discussed method steps until the determined largest traffic load difference is lower than the threshold limit value for all segments.
• this objective is achieved by a gateway of a bus, comprising a plurality of segments, for load balancing of traffic load for non-cyclic messages between the different segments comprised in the bus.
• the gateway is configured to determine the respective traffic load of the segments of the bus.
• the gateway is configured to calculate the respective traffic load difference between the determined respec- tive traffic load of the segments.
• the gateway is in addition configured to determine the largest traffic load difference of the calculated traffic load differences.
• the gateway is configured to compare the determined largest traffic load difference with a threshold limit value.
• the gateway is configured to send a set of messages on the segment of the bus having the lowest determined traffic load, with a frequency based on the calculated respective traffic load difference, wherein the set of messages has a priority level exceeding a first priority level but not exceeding a second priority level.
• the gateway is also configured to generate control signals to iterate the method according to the first aspect of the invention until the calculated traffic load difference is lower than the threshold limit value for all segments.
• Figure 1 A illustrates a bus and a gateway according to an embodiment of the invention
• Figure 1 B illustrates a bus and a gateway according to an embodiment of the invention
• Figure 2 is a combined signalling scheme and flowchart illustrating signal transmission according to some embodiments
• Figure 3 is a flow chart illustrating an embodiment of the method
• Figure 4 is an illustration depicting a system according to an embodiment.
• Embodiments of the invention described herein are defined as a method and a gateway, which may be put into practice in the embodiments described below. These embodiments may, however, be exemplified and realised in many different forms and are not to be limited to the examples set forth herein; rather, these illustrative examples of embodiments are provided so that this disclosure will be thorough and complete.
• FIG. 1 A illustrates a bus 100.
• the bus 100 may be a multi-master serial bus such as e.g. a Controller Area Network (CAN) bus, a Media Oriented Systems Transport (MOST) bus, or similar, in a vehicle.
• the bus 100 comprises a plurality of segments, such as e.g. a first segment 101 and a second segment 102.
• the first segment 101 of the bus 100 extends from a first node 110 and a gateway 130, while the second segment 102 of the bus 100 extends from a second node 120 and the gateway 130.
• the nodes 1 10, 120 may also be referred to as Electronic Control Units (ECUs).
• the nodes 1 10, 120 connected to the bus 100 may typically comprise e.g. sensors, actuators, and other control devices of the vehicle. These devices may be connected to the bus 100 through a host processor, a controller, and a transceiver.
• any of the nodes 1 10, 120 may also be a gateway in some embodiments, allowing a computer to communicate over e.g.
• USB Universal Serial Bus
• Ethernet port to the nodes 1 10, 120 on the bus 100.
• the communication over the segments 101 , 102 of the bus 100 may be wired or wireless in different embodiments.
• the traffic load on the respective segments 101 , 102 of the bus 100 may be very different, e.g. when non-cyclic messages such as diagnosis are transmitted over the bus 100.
• the gateway 130 overviews the load of the connected bus segments 101 , 102.
• the gateway 130 starts sending out dummy messages on the bus segments 101 , 102 having the lowest load, in order to increase the load of that bus segment 101 , 102.
• dummy message is any arbitrary message that does not contain any valid data.
• the priority of the dummy message transmitted by the gateway 130 is higher than the non-cyclic messages but lower than the cyclic functional messages.
• arbitration is a property of e.g. the CAN protocol, for details see International Organisation for Standardisation (ISO) 1 1898.
• the CAN communication protocol is a carrier-sense, multiple-access protocol with collision detection and arbitration on message priority (CSMA/CD+AMP), in some embodiments.
• CSMA means that each node 1 10, 120 on the bus 100 must wait for a prescribed period of inactivity before attempting to send a message.
• CD+AMP means that collisions are resolved through a bit-wise arbitration, based on a preprogrammed priority of each message in the
• Figure 1 B illustrates another embodiment of a bus 100 comprising a plurality of segments 35 101 , 102, 103, 104, 105, 106, 107, 10n, which are connected to a gateway 130.
• the bus 100 may comprise any arbitrary number of segments 101 , 102, 10n in some embodiments.
• Figure 2 schematically illustrates signalling in the different bus segments 101 , 102 of the bus 100.
• the first node 1 10 transmits a first traffic load 201 over the first segment 101 of the bus 100 while the second node 120 transmits a second traffic load 202 over the second segment 102 of the bus 100.
• Figure 2 may illustrate any two network segments 101 -1 On.
• the respective traffic loads 201 , 202 are measured and determined.
• the difference between the first traffic load 201 and the second traffic load 202 is then compared with a predeter- mined or configurable threshold limit.
• the first traffic load 201 on the first segment 101 is much larger than the second traffic load 202 on the second segment 102.
• the first traffic load 201 of the first segment 101 , and the second traffic load 202 of the second segment 102 of the bus 100, respectively, may be determined based on a respective content of a first receiving buffer of the gateway 130, associated with the first segment 101 and a second receiving buffer of the gateway 130, associated with the second segment 102, in some embodiments.
• the gateway 130 starts sending a set of messages 210, i.e. dummy messages on the second segment 102 of the bus 100, which has the lowest traffic load 202.
• the set of messages 210 may have a priority level exceeding a first priority level but not exceeding a second priority level.
• the priority level may thus be set to a higher value than non-cyclic messages (i.e. the first priority level) but lower than cyclic messages (i.e. the second priority level).
• the gateway 130 repeats the measurement of the traffic load 201 , 202 on the respective bus segments 101 , 102, the computation of the difference between the traffic loads 201 , 202, and the comparison between the computed traffic load difference and the threshold limit until the calculated traffic load difference is lower than the threshold limit value.
• the gateway 130 or any of its buffers, is no longer choked.
• the gateway 130 stops sending dummy messages 210. These steps may then be iterated in some embodiments, i.e. the respective traffic load 201 , 202 on the respective bus segments 101 , 102 may be measured continuously, the difference between them may be iteratively calculated and compared with the threshold limit.
• Figure 3 illustrates an example of a method 300 according to an embodiment.
• the flow chart in Figure 3 shows the method 300 in a gateway 130 of a bus 100, comprising a plurality of segments 101 , 102, 10n.
• the method 300 aims at load balancing of traffic load for non- cyclic messages between the different segments 101 , 102, 10n comprised in the bus 100.
• the bus 100 may be a multi-master serial bus in a vehicle, such as e.g. a modular vehicle.
• the vehicle may comprise a means for transportation in broad sense such as e.g. a truck, a car, a motorcycle, a trailer, a bus, a bike, a train, a tram, an aircraft, a watercraft, a cable transport, an aerial tramway, an elevator, a drone, a spacecraft, or other similar manned or unmanned (autonomously controlled or remotely controlled) means of conveyance running e.g. on wheels, rails, air, water or similar media.
• a means for transportation in broad sense such as e.g. a truck, a car, a motorcycle, a trailer, a bus, a bike, a train, a tram, an aircraft, a watercraft, a cable transport, an aerial tramway, an elevator, a drone, a spacecraft, or other similar manned or unmanned (autonomously controlled or remotely controlled) means of conveyance running e.g. on wheels, rails, air, water or similar media.
• the method 300 may comprise a number of steps 301-306. However, some of these steps 301 -306 may be performed in various alternative manners. Fur- ther, the described steps 301 -306 may be performed in a somewhat different chronological order than the numbering suggests.
• the method 300 may comprise the subsequent steps:
• Step 301 comprises determining a respective traffic load 201 , 202 of the segments 101 , 102, 10n of the bus 100.
• the traffic load 201 , 202 of each segment 101 , 102, 10n may be determined based on a respective content of a receiving buffer of the gateway 130, associated with the respective segment 101 , 102, 10n.
• Step 302 comprises calculating a respective traffic load difference between the determined 301 respective traffic loads 201 , 202.
• the traffic load difference may be calculated by subtracting the determined 301 first traffic load 201 from the second traffic load 202, or vice versa.
• the traffic load difference may thus be an absolute value or modulus. This may then be repeated for traffic loads 201 , 202 on all segments 101 , 102 10n of the bus 100.
• Step 303 comprises determining the largest traffic load difference of the calculated 302 traffic load differences between the determined 301 respective traffic loads 201 , 202.
• the largest traffic load difference may be determined by comparing the absolute values of the traffic loads 201 , 202 on all segments 101 , 102, 10n of the bus 100.
• Step 304 comprises comparing the magnitude of the determined 303 largest traffic load difference with a threshold limit value.
• Step 305 comprises sending a set of messages 210 on the segment 101 , 102, 10n of the bus 100 having the lowest determined 301 traffic load 201 , 202, with a frequency based on the calculated 302 respective traffic load difference, wherein the set of messages 210 has a priority level exceeding a first priority level but not exceeding a second priority level.
• the segment 101 , 102, 10n having the lowest determined 301 traffic load 201 , 202 thus has the determined 303 largest traffic load difference, to the traffic load on the segment 101 , 102, 10n having the highest determined 301 traffic load 201 , 202.
• the frequency, i.e. number of messages per time unit, of the messages 210 to be sent may be high when the determined 303 largest traffic load difference is high, i.e. exceeding a threshold limit value; and vice versa.
• the frequency may be adjusted based on the difference between the maximum, or largest, traffic load of any segment 101 , 102, 10n in the bus 100 and the minimum, or lowest traffic load of any segment 101 , 102, 10n in the bus 100.
• the set of messages 210 to be sent has a priority level exceeding a first priority level of non- cyclic messages but not exceeding a second priority level of cyclic messages.
• the set of messages 210 to be sent may be a dummy message, i.e. a message with a nonsense content or benign information that does not contain any useful data.
• Step 306 comprises iterating the method 300 according to steps 301 -305 until the determined 303 largest traffic load difference is lower than the threshold limit value for all segments 101 , 102, 10n.
• messages 210 may be sent 305 until the difference between the segments 101 , 102, 10n of the bus 100 having the lowest and highest traffic load, respectively, has been evened out.
• the traffic loads 201 , 202 of the different segments 101 , 102, 10n of the bus 100 may be continuously surveyed, and a buffer overflow in the gateway 130 may be avoided.
• Figure 4 illustrates an embodiment of a bus 100, comprising a plurality of segments 101 , 102, 10n.
• the bus 100 also comprises a gateway 130, configured to perform at least some of the previously described steps 301 -306 according to the method 300 described above and illustrated in Figure 3, for load balancing of traffic load 201 , 202 for non-cyclic messages between the respective segments 101 , 102, ..., 10n of the bus 100.
• the gateway 130 of the bus 100 is configured to determine the respective traffic load 201 , 202 of the segments 101 , 102, ..., 10n of the bus 100. Further, the gateway 130 is configured to calculate the respective traffic load difference between the determined respective traffic load 201 , 202 of the segments 101 , 102, 10n. The gateway 130 is in addition configured to determine the largest traffic load difference of the calculated traffic load differences. Furthermore, the gateway 130 is also configured to compare the determined largest traffic load difference with a threshold limit value.
• the gateway 130 is further configured to send a set of messages 210 on the segment 101 , 102, 10n of the bus 100 having the lowest determined traffic load 201 , 202, with a frequency based on the calculated respective traffic load difference, wherein the set of messages 210 has a priority level exceeding a first priority level but not exceeding a second priority level.
• the gateway 130 is also configured to generate control signals to iterate the method 300 according to steps 301 -306 until the calculated traffic load difference is lower than the threshold limit value for all segments.
• the gateway 130 may in some embodiments be configured to send the message 210, wherein the message 210 is used for load balancing and contains any data.
• the gateway 130 may further be configured to send the message 210 with a priority level exceeding a first priority level of non-cyclic messages but not exceeding a second priority level of cyclic messages.
• the gateway 130 may also be configured to send dummy messages 210.
• the gateway 130 may comprise a first buffer 410 for receiving signals and messages over a first segment 101 from a first node 1 10 and a second buffer 420 for receiving signals and messages over a second segment 102 from a second node 1 10, in some embodiments.
• the gateway 130 may comprise a buffer corresponding to each segment 101 , 102, 10n of the bus 100, in some embodiments.
• the gateway 130 comprises a processor 430 configured for performing at least some steps 301 -306 of the above described method 300, according to some embodiments.
• Such processor 430 may comprise one or more instances of a processing circuit, i.e. a Central Processing Unit (CPU), a processing unit, a processing circuit, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions.
• a processing circuit i.e. a Central Processing Unit (CPU), a processing unit, a processing circuit, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions.
• CPU Central Processing Unit
• ASIC Application Specific Integrated Circuit
• microprocessor or other processing logic that may interpret and execute instructions.
• the herein utilised expression "processor” may thus represent a pro- 15 cessing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones enumerated above.
• the gateway 130 may comprise a signal transmitter 440 in some embodiments.
• the signal transmitter 440 may be configured for transmitting a signal to various segments 101 , 20 102, 10n of the bus 100.
• the gateway 130 may comprise a memory 450 in some embodiments.
• the optional memory 450 may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis.
• the memory 450 may comprise integrated circuits comprising silicon-based transistors.
• the memory 450 may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.
• the above described method steps 301 -306 to be performed in the gateway 130 may be implemented through the one or more processors 430 of the gateway 130, together with a computer program for performing at least some of the functions of the method steps 301 - 306.
• a computer program comprising instructions for performing the method steps 301 - 35 306 in the gateway 130 may perform the method 300 for load balancing of traffic load for cyclic messages in the different segments 101 , 102, ..., 10n of the bus 100 comprised in the bus 100 when the computer program is executed in the processor 430 in the gateway 130.
• the computer program mentioned above may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the method steps 301 -306 according to some embodiments when being loaded into the one or more processors 430 of the gateway 130.
• the data carrier may be, e.g., a hard disk, a CD ROM disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner.
• the computer program product may furthermore be provided as computer program code on a server and downloaded to the gateway 130 remotely, e.g., over an Internet or an intranet connection.
• the term “and/ or” comprises any and all combinations of one or more of the associated listed items.
• the term “or” as used herein, is to be interpreted as a mathematical OR, i.e., as an inclusive disjunction; not as a mathematical exclusive OR (XOR), unless expressly stated otherwise.
• the singular forms “a”, “an” and “the” are to be inter- preted as “at least one”, thus also possibly comprising a plurality of entities of the same kind, unless expressly stated otherwise.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
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• Health & Medical Sciences (AREA)
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• General Health & Medical Sciences (AREA)
• Medical Informatics (AREA)
• Small-Scale Networks (AREA)
• Data Exchanges In Wide-Area Networks (AREA)

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• 2016
  • 2016-09-26 SE SE1651265A patent/SE540244C2/en unknown
• 2017
  • 2017-09-14 WO PCT/SE2017/050904 patent/WO2018056883A1/en active Application Filing
  • 2017-09-14 DE DE112017004161.9T patent/DE112017004161B4/de active Active

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