文本英特介绍updateethernet

1、INTREPID CONTROL SYSTEMSAutomotive Ethernet TrainingAgendaRelevant OrganizationsIntroduction to Vehicle NetworksAutomotive Ethernet: Why?Networking FundamentalsThe OSI ModelWorking Our Way Up “The Stack”Audio Video Bridging / Time Sensitive NetworkingRelevant OrganizationsAutomotive Ethernet SIG(IEE

2、E 100BASE-T1, 1000BASE-T2, 1000BASE-RH)Institute of Electrical and Electronics Engineers (802.3, 802.11, 802.1AS, 802.bla.bla) Internet Engineering Task Force (IETF)RFCs (793, 768, 791)International Organization for Standardization (ISO14229, ISO15765-2, ISO7498-1)Relevant OrganizationsAssociation f

3、or Standardization of Automation and Measuring SystemsAUTomotive Open System ARchitectureSociety of Automotive Engineers (J1962, J1939, J2534)AVB / TSN CertificationCore Competency / Commitment toAutomotive EthernetWe wrote the Ethernet Bible!Three of the four authors work for IntrepidPaying sponsor

4、 of the OPEN Alliance project management systemWe platinum sponsor manyIEEE Ethernet eventsWe have more than 60 man-years of combined experience in Automotive Ethernet technologies.We have many hundreds of man-years in automotive network testing. Millions of vehicles on the road are tested with Intr

5、epid products!OPEN ALLIANCE SIGAutomotive Networks OverviewAutomotive Networking isAt a high level, automotive networking is the same as the computer networking you are already familiar with. It is a collection of computers that share data with one another.DataMotivation for Vehicle NetworksDiagnost

6、ics were the initial motivationSteady growth of vehicle content/features:Influx of actuators, motors, sensors, controllersHundreds of meters of copper wiring and growing.Equal growth in industry challenges:Reduce cost/weightIncrease quality (component and plant diagnostics)Increase reliability (Fewe

7、r wires/connections = fewer opportunities for failure)Vehicle optimization quickly became another motivationAutomotive communication networks take root!Arrival of low-cost 8-bit microcontrollers: “game changer”ECMBCMIPCDCMDCMRadioABSHVACRPAMSMTMMPODSBrief History of Automotive NetworkingBefore the 1

8、990s, automotive networking was mostly non-standardized:GM: ALDL / Class2 (aka J1850 VPW) Chrysler: CCD (Chrysler Collision Detection) Ford: SCP (Serial Communications Protocol) / J1850 PWMToyota: BEAN (Body Electronic Area Network) / ISO9141What took so long?Some OEMs just didnt see the value of st

9、andardization in this area.Mindset that mechanical innovation drove competitive advantage, while electronics were secondary.Along comes Bosch:CAN developed by Bosch and Intel in the late 1980sIn the 1990s, Bosch dominated electronics content in European vehiclesCAN perfectly positioned to drive stan

10、dardization across OEMsCAN Solution Reduced WeightAnnounced in 1986 by Bosch and IntelFirst chips available in 1988First used in a mass-production car in 1990 (Mercedes S Class Model 140)Complexity SkyrocketsCount of ECUs increasesCount of CAN networks increases:CheapSecureJ1850 running out of bandw

11、idthHigher protocols find their way into the world of CAN20+ ECUs per vehicle commonCAN es the worldwide standardCAN CANnot Any LongerRising demands for bandwidth, QoS, and determinism:Decentralization of functionsIntegration of consumer products and servicesStreaming mediaV2X / Autonomous vehiclesC

12、ANs evolution to CAN FD addresses bandwidth, but not growing gaps in other areasECMBCMRadarIPCDCMDCMRadioABSHVACRPAMSMGWMBSMBECRadarV2XTMMRSERSECameraCameraCameraCameraActive SafetyPODSWhat is Different in Automotive Networking?Component Availability / Durability Consumer ElectronicsAutomotive Elect

13、ronicsDriven by the latest and greatest performance, size, features, etc.Driven by quality and reliability (and of course, cost.)Almost disposable after 1 to 2 years. Reparability not a design concern.Service parts rarely a consideration.Expected useful life of 15+ years.Vehicle must be repairable.S

14、ervice parts must be available 10+ years after last year of production.Fewer components than an automobile. “Clean sheet” redesign possible for new products.Verified “carryover” designs used for many years to avoid development costs. “Clean sheet” redesign almost never economical. Average LIFE of ta

15、blet = 2.1 yearsAverage AGE of car = 11.4 years!CAN and Ethernet Volume2014 = 1.2 billion CAN nodes2014 = 400 million Ethernet ports Power Management / Sleep Modes10 - 100 A sleep / standby modesMust wake up from the network only without extra wires100 ms wakeup time is typicalSwitched / non-switche

16、d ECUs operate togetherEvery watt used in automotive electronics comes out of gas mileage or battery rangeHarsh EnvironmentWater / mud -40C to +125CDirt, salt, dust, snow, grease, etc.Car in Winter (Michigan)Car in Summer (Michigan)Vehicle Networks at a GlanceNetworkCostBandwidth(Mbps)MediumTopology

17、Primary ApplicationDifferentiating FeaturesUART$1UTPMultidropN/ALow CostLIN$0.02Single Wire BusMultidropSwitches/SensorsLow CostCAN$1UTPMultidropGeneral PurposeRobustFlexRay$10UTPMultidropSafety Critical SystemsSynchronousDeterministicMOST$25/50/150UTPFiberRingInfotainmentSynchronousDeterministicCAN

18、 FD$8+UTPMultidropGeneral PurposeRobustHigher Data Rates 100/1000BASE-T1$10/100/1000UTPSwitched NetworkEvolving to All-PurposeLets Discuss.Ethernet Adapts to Automotive ChallengesCost and Weight: Two wires with no shieldingPower: Power saving modesSleep: Must have low-power modes that enable wakeup

19、/ sleep over the same physical medium (no on/off switches in the car). NOT DONE YET!EMC: Low emissions around critical radio bands; immunity to spark plugs and injectorsHarsh Environment: Certified for automotive useEmbedded System: Video captureNot consumer electronics: Multiple sources ( , Marvell

20、, NXP so far)How Is This Possible?OSIUpperLayersOSI Lowest Layer:Physical LayerEthernet MAC10/100/1000PHYEthernet MAC100BASE-T1PHYMIIMII: Media Independent Interface=The Wonderful Results: Ethernet LeverageWe can reuse any Ethernet software technology and hardware technology from the MAC on up.Every

21、 Microcontroller 10/100 MACEvery RFC Every Engineer/DeveloperSkilled in TCP/IPState of Ethernet in CarsTOO BIG TO FAIL!Many production plans in placeExample Vehicle Network TopologyComparing Ethernet to CAN, LIN, FlexRayand MOSTAutomotive Ethernet(100BASE-T1 / 1000BASE-T1)Up to 1000 Mb/s (each direc

22、tion and each leg)Widely used technology (much support)Good clock synchronization technology available (based on IEEE 1588)Requires a switchNot possible to add or remove nodes unless the switch has spare portsMore expensive than CANTools cannot just connect and sniff the busCANMultidrop topology wit

23、h the ability to add and remove nodes without major effects on other nodesEasy environment for tool manufacturers: plug and playCAN Node 1CAN Node 2CAN Node 3CAN Node XFlexRayMultidrop topologyUp to 10 Mb/s (10 times greater than normal CAN)Completely new message structureClock synchronizationDeterm

24、inistic (static frames)Must design the entire network at one timeAll nodes must be aware of and programmed for the entire network designMore expensive than CANMuch more complicated than CANFlexRayMOST Media Oriented Serial TransportOne break in the ring? The whole network goes down!Tools must be a p

25、art of the ring. Problem with the tool? Ring goes down!Optical cables are expensive to service. (MOST50 covers this with copper wire.)Expensive compared to CAN.Head UnitDisplaySpeakerScreen2Applications of EthernetInfotainmentDiagnostics over IPXCP on EthernetETHERNETSafetyCameraCameraCameraCameraRa

26、darV2XMulti-DomainModuleEthernet BackboneLINCANFlexRayMOST1 2 5 10Relative cost per nodeData rate bps20K1M10M25MCost vs. Data Rate100M150MCAN-FDEthernetThe powerof the switch! Stay tuned!300M100 MbSummaryEthernet is going to be a big part of tomorrows vehicles.Ethernet will not replace existing stan

27、dards, only augment them.Ethernet provides new possibilities to the vehicle, including extremely high speed interfaces to cameras and video displays.The application of tools is different than in CAN, MOST, FlexRay and LIN.Networking Fundamentals Packet SwitchingData broken into chunks and sent indep

28、endentlyRoutes determined dynamically based on costUsed by most modern networks, such as EthernetAdvantages: flexibility, performance, utilizationFrame FormattingProtocols define formats for their messagesGeneral format: header, data, optional footerHeader: control and management information (Like C

29、ANs ID, DLC)Data: information being carried; also “payload”Footer: information put after data (like CANs CRC, Ack, and EOF)Message Addressing MethodsUnicast: one to oneGMLAN / UDSdiagnostics Broadcast: one to allCAN broadcast msgsTechnically ALL CANmsgs are alwaysbroadcastMulticast: one to manyNetwo

30、rking TopologiesDefine how devices are connected togetherDetermine network characteristicsSimple topologies:Point-to-point (or port)Bus (chained or attached) - like CAN and LINRingStarComplex topologies combine theseHierarchical Star TopologyAlso “tree topology” or “star of stars”Multiple levels can

31、 be createdTodays Ethernet NetworkOriginally Ethernet was a bus architecture: more than two nodes could exist on one physical medium.All modern networks are star topology: only one node per switch port.Impossible for Ethernet frames to “collide” using modern full-duplex communication.Each leg (A,B,C

32、) acts as its own network.“Plex” Deciding Who Can Transmit WhenSimplex: one-way streetHalf-Duplex: two or more, but one at a time CAN / LINFull-Duplex: two devices at the same time“Dual simplex” two one-way streets“True full-duplex” uses one physical linkThe OSI Reference ModelThe OSI Reference Mode

33、lOpen Systems Interconnection = OSICreated as part of ISO protocol suiteModel became universal due to its usefulnessDefines 7 layers, their functions and interactionsMost common way of referring to “where” a technology “lives” and thus its roleModularity essential to developing modern complex networ

34、ksData EncapsulationProtocol data unit = header + payloadA PDU created at one layer es the payload of the service at the next lower levelAs the original data is passed down the layer stack of a transmitter, each layer adds its own headerMessages are nested like “Russian dolls”The receiver passes the

35、 nested message back up the stack, where each header is used to control that layers operation and is then removedLayers and Layer GroupingsLayers numbered in increasing order from most concrete to most abstractLower layers: 1 to 4Upper layers: 5 to 7Layer 4 can go in either placeSome technologies do

36、nt fitthe paradigm strictly (TCP/IP)Some ignore this model entirely (AVB/TSN)UpperLayersLowerLayersLayer 1: Physical LayerPhysical network design and topologyDefinition of media hardware specsEncoding and signalingWhere data transmission and reception take placeCAN transceiver fits hereOften divided

37、 into sublayersIntegral relationship to layer 2Most LANs defined here and layer 2,including Ethernet, CAN and Wi-FiLayer 2: Data Link LayerMedia access control: medium contention or advanced methodsLow-level device addressingLow-level message formatting Low-level error detectionFeatures such as VLAN

38、s and QoSCAN controller fits hereLAN technologies generally span layers 1 and 2IEEE 802 split: MAC and LLCARP: interfaces layers 2 and 3Layer 3: Network LayerLogical device-level addressingInternetworkingRoutingUniversal encapsulationFragmentation and reassemblySupport and administrationExample prot

39、ocols:ISO 15765-2 “Long Messages” (Layers 3/4)Internet Protocol (IP)Internet Control Message Protocol (ICMP)Routing protocolsLayer 4: Transport LayerSoftware- and process-level addressingLogical connectionsMultiplexing and demultiplexingService quality guarantees(acknowledgment and flow control)Exam

40、ple protocols:Transmission Control Protocol (TCP)(usually closely related to layer 3, thus “TCP/IP”)User Datagram Protocol (UDP)“Long messages” flow controlGMLAN / UDS ECU addressingLayer 5: Session LayerEstablishment and management of sessions between software instances on different devicesOften no

41、t explicitly defined in actual network layer stacksExamplesApplication program interfaces:e.g. J2534 passthruDiagnostic sessions:Tester presentextendedDiagSession, etc.Cybersecurity (unlocking)Layer 6: Presentation LayerPrimarily deals with handlingdifferences in data “presentation”:TranslationCompr

42、ession and pressionEncryption and decryptionAnother layer that may not beexplicitly defined or usedCybersecurity: unlocking does notsit here, but data encryption on thenetwork doesLayer 7: Application LayerProtocols that implement networkapplicationsClosest to the end user and sothe most commonly en

43、counteredoutside the “techie world”Hypertext Transfer Protocol (HTTP)is a classic exampleAn application layer protocol is not the same as an applicationPhysical LayerPhysical LayerBit Stream, Physical Medium, Methods of Transferring Data1234567Network LayerIP Addressing, RoutingTransport LayerTCP /

44、UDPData Link LayerThe Ethernet Frame, MAC AddressesSession LayerInterhost CommunicationPresentation LayerApplication Layer57Physical Layer100/1000BASE-T11 twisted pair2 wiresFull-duplex1 Gbps now available! (1000BASE-T1)A Simple Ethernet NodeMicrocontrollerEthernet MACEthernet PHYMIIFull Duplex Ethe

45、rnetAn Ethernet Node consists of a microcontroller, an Ethernet MAC controller and an Ethernet physical layer (PHY).An industry standard digital link called the Media Independent Interface (MII) enables different PHYs to be used with any MAC.Media ConvertersConvert between different Physical Layer i

46、mplementations of same network Commonly used in AE to connect 100/1000BASE-T1 to conventional (“four-pair”) EthernetIntrepids RAD-Moon:100BASE-T1 to 100BASE-TXEssentially two different PHYs connected back-to-backSimple but incredibly usefulIntrepids RAD-SuperMoon:100/1000BASE-T1 to 100/1000BASE-TXAV

47、B/TSN endpoint simulationCombine 2 RAD-SuperMoons to implement an active tapIntrepid Automotive Ethernet TrainingHands-On: Lab Manual Sections 1.1-1.2: TogetherSection 1.3a-f: On Your OwnData Link LayerData Link LayerThe Ethernet Frame, MAC Addresses1234567Network LayerIP Addressing, RoutingTranspor

48、t LayerTCP / UDPPhysical LayerBit Stream, Physical MediumSession LayerInterhost CommunicationPresentation LayerApplication LayerThe Ethernet FrameCarries the data on EthernetFrames can carry 46 to 1,500 bytes of data12,336 bits at 100 Mb/s takes 123.4 s (similar to a 1 Mb/s 8 byte data frame)Preambl

49、e / Start of Frame DelimiterPreamble: 7 bytes of 10101010Start of frame delimiter (SFD): 10101011Ethernet world octet = byte Preamble provides signal edges so network device clocks can synchronize with each otherMAC AddressLow-level / physical network address:Programmed into hardware devices6 bytes

50、long, each node globally uniqueFirst 3 bytes is registered to an organization (OUI)In AE, MAC address = Ethernet addressUsed to direct data on an Ethernet network:Used in all 802 protocols (such as Wi-Fi)Source / destinationSpecial MAC addresses for broadcasting Reserved MAC AddressesBroadcast Messa

51、gesMAC address is all 1s (FF:FF:FF:FF:FF:FF hex)Intended for all NICs to listen toMulticast MessagesSpecific MAC address that certain NICs are programmed to acceptFirst byte of the MAC address is “01”Used for protocol, process or vendor specific messagingUnicast messages (point-to-point)First byte o

52、f the MAC is set to “00”Used to send data to a specific nodeVirtual LANs (VLANs)Traditional automotive CAN solutions:Private CANAdd CAN busesLIN subnet / virtual networksEthernet can allocate devices to “virtual LANs”:Each VLAN sees only its own trafficAllows modularity, using available bandwidth if

53、 option is availableAllows features such as AVB, which can be used for critical systems and infotainmentVLAN TaggingVLAN tag (optional) contains a priority and a VLAN identifierUsed by protocols to isolate networks and to control bandwidth (AVB)Supports double tagging (VLAN within a VLAN)Devices not

54、 supporting VLANs wont recognize the EtherType and discard such frames0 x8100 in the first 2 octets designates the frame as having a VLAN tag. Any other value implies that the field is not present.Tagged VLAN Frame Structure LAN Design with Two VLANsDevices in VLAN 1 and VLAN 2 are connected to the

55、same switch but treated distinctlyA broadcast from device #5 is not seen in VLAN 1Common AE EthertypesEthertype / Length16-bit value identifying specific protocol of a frameValue 1536 designates length instead of protocolGeneral Use0 x0800IPv40 x86DDIPv60 x0806Address Resolution Protocol0X8100VLAN -

56、 Single Tag0 x9100VLAN - Double Tag0 x88F5Multiple VLAN Reservation ProtocolAVB0 x22F0IEEE 17220 x88F7generalized Precision Time Protocol0 x22EAMultiple Stream Reservation ProtocolV2X0 x88DCWave Short Message ProtocolPayloadWhere the actual Ethernet data isFor example, the beginning of the IP header

57、 starts hereFrame Check Sequence (CRC)Cyclical redundancy check for data integrityIf the CRC fails, the frame is usually discarded by the switch or Ethernet MACNo built-in error recovery like CAN (this is implemented at higher layers; hint: TCP)Ethernet Switch Operationand Traffic MonitoringWhy Use

58、Switches?Fundamentals of Transparent SwitchingSwitches must know which devicesconnect to it over which ports“Transparent” because this knowledge is learnedLookup tables are maintainedfor each port listing which devices are connected to itSpecial handling is necessary for multicast and broadcast fram

59、esModern switches support full-duplex operationSwitch LearningSwitch powers on not knowing where hosts areWhen the first frame arrives, the switch must “flood” it to all ports (like a hub)It records that frames source address in the table for the port it came from:It has “learned” where that frames

60、sender residesWhen a frame later arrives intended for that device, it can forward it without floodingProcess continues until all hosts are foundDo We Need All of This in AE?Good question! There are several possibilities:Lock down all the addresses: saves boot time for infotainment, cameras, etc.Use