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Guaranteeing Hard Real-Time Requirements of In-Vehicle Multihop Communication Over COTS Ethernet Hardware
Technical Paper
2011-01-1038
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Automakers currently use Ethernet for fast batch transfers when updating software in ECUs in a vehicle. But Ethernet is also planned for real-time traffic as well; in the short term future for streaming of video and audio and potentially in the long term also for Drive-by-wire functions.
Ethernet today uses the same frame format as the original Ethernet from the 1970s did but except from that it bears little resemblance to its original form. Ethernet today uses switches and hence the argument often raised against its use for carrying hard real-time traffic - that the shared medium can cause unbounded delay due to collisions - is not applicable today. In addition, normal Ethernet switches today support prioritization of traffic which allows an engineer to assign a high priority to urgent time-critical traffic so that its queuing delay is not affected by lower priority (supposedly less time-critical) traffic.
Although the high bit-rate and the ability to control queuing delays thanks to prioritization are attractive for carrying real-time traffic, this alone cannot guarantee that real-time requirements are fulfilled. It is necessary to prove with mathematical rigor that given a traffic model and given the topology and configuration of the network, all real-time requirements will be met. Such proof techniques are known for the CAN bus and they have been adopted in design tools. Such proofs are also known for star networks based on switched Ethernet for simple traffic models but no design tool is currently based on them.
Therefore, in this paper, we list desired functionalities of a tool for proving that timing requirements are fulfilled. It should sport the ability to analyze multihop traffic over switched Ethernet networks and allow designers great freedom in how flows are described in order to reduce pessimism of the analysis due to modeling.
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Lext, J., Bröhne, L., and Andersson, B., "Guaranteeing Hard Real-Time Requirements of In-Vehicle Multihop Communication Over COTS Ethernet Hardware," SAE Technical Paper 2011-01-1038, 2011, https://doi.org/10.4271/2011-01-1038.Also In
References
- Gumbrich, S. “Embedded systems overhaul -It's time to tune up for the future of the automotive industry,” IBM Business Consulting Services 2004 http://www-05.ibm.com/de/automotive/downloads/embedded_systems_overhaul.pdf
- CAN Specification. Version 2.0 1991 Robert Bosch GmbH www.semiconductors.bosch.de/pdf/can2spec.pdf
- Mok, A. K. Ward, S. Distributed broadcast channel access Computer Networks 3 327 335 1979
- Davis, R. I. Burns, A. Bril, R. J. Lukkien, J. J. “Controller Area Network (CAN) schedulability analysis: Refuted, revisited and revised,” Real-Time Systems 35 3 April 2007 239 272
- Pereira, N. Andersson, B. Tovar, E. “WiDom: A Dominance Protocol for Wireless Medium Access,” IEEE Transactions on Industrial Informatics 3 2 May 2007 120 130
- Kopetz, H. Grünsteidl, G. TTP - A Time-Triggered Protocol for Fault-Tolerant Real-Time Systems FTCS 1993 524 533
- http://www.flexray.com/
- Thomsen, T. Drenkhahn, G. “Ethernet for AUTOSAR,” http://www.autosar.org/download/conferencedocs/07_Elektrobit_Ethernet_for_Autosar.pdf
- http://www.esk.fraunhofer.de/fhg/Images/PDB_RTE_en_tcm254-170680.pdf
- AVnu Alliance http://www.avnu.org/audiences#automotive
- “Beyond FlexRay: BMW airs Ethernet plans,” http://www.eetimes.com/electronics-blogs/other/4200470/Beyond-FlexRay-BMW-airs-Ethernet-plans
- Reichart, Dr. G. Former Vice President, Body and Safety Electronics, Driver Assistance, Wiring Harness BMW Group “AUTOSAR and beyond - Some comments on automotive HW/SW-Architectures & Processes,” http://www.mentor.com/events/transconf/detroit/presentations/upload/detroit-10-2.pdf
- http://www.ethercat.org/
- http://www.profibus.com/technology/profinet/
- http://www.ethernet-powerlink.org/
- Micrel data sheet for KSZ8873 http://www.micrel.com/_PDF/Ethernet/datasheets/KSZ8873MLL_FLL_RLL_DS.pdf
- “Dongbu HiTek to Manufacture Automotive Ethernet ICs” http://www.dongbuhitek.com/eng/Mediaroom/board_detail.asp?BoardId=Media&Idx=265
- SMSC data sheet for LAN89303 http://www.smsc-ais.com/AIS/download.php?id=449&filename=LAN89303AM DS Rev. 1.1 (08-03-10).pdf
- Westermo data sheet for RFI-10P http://www.westermo.com/dman/Document.phx/Datasheets/Ethernet/English/rfi-10+datasheet+ENG.pdf
- Westermo, RedFox User guide http://www.westermo.com/dman/Document.phx/Manuals/Ethernet/Ethernet+Switches/RedFox+Manual.pdf
- Westermo New June 2010 http://www.westermo.com/dman/Document.phx/Media+Archive/Brochures/News+Brochures/westermo_news_1006_SE.pdf?folderId=%2FMedia+Archive%2FBrochures%2FNews+Brochures&cmd=download
- Marvell 88E6092 http://www.marvell.com/products/switching/linkstreet/marvell_linkstreet_88E6092_product_brief.pdf
- Tindell, K. Clark, J. “Holistic schedulability analysis for distributed hard real-time systems,” Microprocessing and Microprogramming 40 2-3 April 117 134 1994
- AUTOSAR http://www.autosar.org/
- Wireshark www.wireshark.org
- IEEE 1616a-2010 http://bmsmail3.ieee.org:80/u/17205/248373