1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 10681-2:2010Road vehicles Communication on FlexRayPart 2: Communication layer servicesBS ISO 10681-2:2010 BRITISH STANDARDNational forewordThis British Standard is the UK
2、implementation of ISO 10681-2:2010.The UK participation in its preparation was entrusted to TechnicalCommittee AUE/16, Electrical and electronic equipment.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all
3、 the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 62869 6ICS 43.040.15Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Stra
4、tegy Committee on 31 July 2010Amendments issued since publicationDate Text affectedBS ISO 10681-2:2010Reference numberISO 10681-2:2010(E)ISO 2010INTERNATIONAL STANDARD ISO10681-2First edition2010-06-15Road vehicles Communication on FlexRay Part 2: Communication layer services Vhicules routiers Commu
5、nication par FlexRay Partie 2: Services de la couche de communication BS ISO 10681-2:2010ISO 10681-2:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which
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10、 Published in Switzerland ii ISO 2010 All rights reservedBS ISO 10681-2:2010ISO 10681-2:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms, definitions, symbols and abbreviated terms. 2 4 Conventions 4 5 Communication layer
11、 overview. 4 6 Communication layer services 10 7 Communication layer protocol 22 8 Data link layer usage 48 Annex A (informative) Implementation examples . 58 Bibliography . 64 BS ISO 10681-2:2010ISO 10681-2:2010(E) iv ISO 2010 All rights reservedForeword ISO (the International Organization for Stan
12、dardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right
13、 to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International S
14、tandards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an
15、International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 10
16、681-2 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3, Electrical and electronic equipment. ISO 10681 consists of the following parts, under the general title Road vehicles Communication on FlexRay: Part 1: General information and use case definition Part 2: Communica
17、tion layer services BS ISO 10681-2:2010ISO 10681-2:2010(E) ISO 2010 All rights reserved vIntroduction This part of ISO 10681 is based on the Open Systems Interconnection (OSI) Basic Reference Model specified in ISO/IEC 7498-1 and ISO/IEC 10731, which structures communication systems into seven layer
18、s (see example in Table 1). When mapped on this model, this part of ISO 10681 incorporates the network layer (layer 3) and the transport layer (layer 4) services as communication layer services. Table 1 Example of enhanced diagnostic specifications according to the OSI layers Applicability OSI layer
19、s Vehicle manufacturer enhanced diagnostics Application layer ISO 14229-1 Presentation layer N/A Session layer ISO 14229-2 Transport layer Network layer ISO 10681-2 Data link layer FlexRay Communications Systems Protocol Specification Seven layers according to ISO/IEC 7498-1 and ISO/IEC 10731 Physic
20、al layer FlexRay Communications System Electrical Physical Layer Specification BS ISO 10681-2:2010BS ISO 10681-2:2010INTERNATIONAL STANDARD ISO 10681-2:2010(E) ISO 2010 All rights reserved 1Road vehicles Communication on FlexRay Part 2: Communication layer services 1 Scope This part of ISO 10681 spe
21、cifies the requirements for a communication protocol tailored to meet the requirements of FlexRay-based vehicle network systems as specified in the FlexRay Communications Systems Protocol Specification. As the communication protocol combines the network layer and transport layer functionality (OSI l
22、ayers 3 and 4), this part of ISO 10681 does not explicitly distinguish between these layer services. The technical features of this communication protocol are as follows: transmit messages with known data length; transmit messages with unknown but finite data length; additional acknowledgement with
23、retry mechanism; routing data on the fly; support of dynamic frame length. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referen
24、ced document (including any amendments) applies. ISO/IEC 7498-1, Information technology Open Systems Interconnection Basic Reference Model: The Basic Model ISO 7498-2, Information processing systems Open Systems Interconnection Basic Reference Model Part 2: Security Architecture ISO/IEC 7498-3, Info
25、rmation technology Open Systems Interconnection Basic Reference Model: Naming and addressing ISO/IEC 7498-4, Information processing systems Open Systems Interconnection Basic Reference Model Part 4: Management framework ISO/IEC 10731, Information technology Open Systems Interconnection Basic Referen
26、ce Model Conventions for the definition of OSI services BS ISO 10681-2:2010ISO 10681-2:2010(E) 2 ISO 2010 All rights reserved3 Terms, definitions, symbols and abbreviated terms 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in ISO/IEC 7498-1, ISO 7498-2,
27、 ISO/IEC 7498-3 and ISO/IEC 7498-4 and the following apply. 3.1.1 communication layer CL layer that includes the network layer (layer 3) and the transport layer (layer 4) 3.1.2 protocol data unit PDU layered system data unit that is specified in the protocol of a given layer NOTE The protocol data u
28、nit contains user data of that layer and possible protocol control information. The protocol data unit of layer X is the service data unit of its lower layer (X 1). 3.1.3 service data unit SDU layered system set of data that is sent by a user of the service in a given layer NOTE It is transmitted to
29、 a peer service user with no semantic change. 3.2 Abbreviated terms For the purposes of this document, the following abbreviated terms apply. ABT abort ACK acknowledge BC bandwidth control BfS buffer size BP byte position C_AI communication address information C_Ar communication layer timing paramet
30、er A receiver C_As communication layer timing parameter A sender C_Br communication layer timing parameter B receiver C_Bs communication layer timing parameter B sender C_Cr communication layer timing parameter C receiver C_Cs communication layer timing parameter C sender C_CT communication type C_D
31、ata communication layer data transfer service name C_PCI communication protocol control information C_SA communication source address C_TA communication target address BS ISO 10681-2:2010ISO 10681-2:2010(E) ISO 2010 All rights reserved 3C_TAType communication target address type CF consecutive frame
32、 CL communication layer COMM communication CTS continue to send C_PDU communication layer protocol data unit C_SDU communication layer service data unit DLL data link layer ECU electronic control unit EOB end of block FC flow control FIFO first in first out FPL frame payload length FR FlexRay FS flo
33、w status Ind indication LF last frame L_PDU data link layer protocol data unit max maximum ML message length MNPC maximum numbers of PDUs per cycle N/A not applicable N_PDU network protocol data unit NUM number OVFLW overflow PDU protocol data unit pLatestTx latest point of transmission Req request
34、RET retry RX receive SCexp separation cycle exponent SDU service data unit SN sequence number STF start frame STFA start frame acknowledged STFU start frame unacknowledged BS ISO 10681-2:2010ISO 10681-2:2010(E) 4 ISO 2010 All rights reservedUNEXP unexpected UNUM unsigned numeric TX transmission WFT
35、wait frame transmission WT wait 3.3 Symbols summation not equal 4 Conventions ISO 10681 is based on the conventions discussed in the OSI Services Conventions (ISO/IEC 10731:1994) as they apply for diagnostic services. 5 Communication layer overview 5.1 General This clause describes the overall funct
36、ionality of the communication layer. This part of ISO 10681 specifies an unacknowledged and acknowledged communication layer protocol for the exchange of data with known or unknown length between network nodes, e.g. from ECU to ECU, or between a diagnostic tester equipment and an ECU. If the data to
37、 be transferred do not fit into a single L_PDU, a segmentation method is provided. In order to describe the function of the communication layer, services provided to upper layers and the internal operation of the communication layer have to be considered. 5.2 Services provided by communication layer
38、 to upper layers The service interface defines a set of services that are needed to access the functions offered by the communication layer, i.e. transmission/reception of data and setting of protocol parameters. Four types of services are defined. a) Communication services These services, of which
39、the following are defined, enable the transfer of up to 64 kbytes of data. 1) C_Data.request This service is used to request the transfer of data. If necessary, the communication layer segments the data. 2) C_Data_STF.indication This service is used to signal the beginning of a segmented message rec
40、eption to the upper layer. 3) C_Data.indication This service is used to provide received data to the upper layer. BS ISO 10681-2:2010ISO 10681-2:2010(E) ISO 2010 All rights reserved 54) C_Data.confirm This service confirms to the upper layer that the requested service has been carried out (successfu
41、lly or not). b) Protocol parameter setting services These services, of which the following are defined, enable the dynamic setting of protocol parameters. 1) C_ChangeParameter.request This service is used to request the dynamic setting of specific internal parameters. 2) C_ChangeParameter.confirm Th
42、is service confirms to the upper layer that the request to change a specific parameter has been carried out (successfully or not). 3) C_GetParameter.request This service is used to request the value of a communication layer parameter for a given connection. 4) C_GetParameter.confirm This service is
43、used to return the value of a communication layer parameter for a given connection. c) Status services 1) C_GetStatus.request This service is used to request the status of a transfer of data (transmit/receive). 2) C_GetStatus.confirm This service confirms to the upper layer the status of the transfe
44、r of data (transmit/receive). d) Transmission control services C_Cancel.request This service is used to request cancellation of an ongoing message transmission. This request can only be issued by the sender of a message, after the message transmission has been started via a C_Data.request service pr
45、imitive. 5.3 Internal operation of communication layer 5.3.1 General The internal operation of the communication layer provides the following methods for segmentation, transmission with flow control, and reassembly: transmission of a message with a known message length; transmission of a message wit
46、h an unknown but finite message length; acknowledgement of the transmission with a retry mechanism. BS ISO 10681-2:2010ISO 10681-2:2010(E) 6 ISO 2010 All rights reservedThe main purpose of the communication layer is to perform a transfer of a message that might or might not fit in a single FlexRay f
47、rame. Messages which do not fit into a single FlexRay frame are segmented into multiple parts, where each can be transmitted in a FlexRay frame. 5.3.2 Rules The communication layer establishes certain rules for an ongoing transmission/reception, which are briefly described here for better understand
48、ing of the examples given in 5.3.3. For details on certain frames and their usage, see 7.4. Segmented messages are always concluded with a LastFrame. This frame might include the last bytes of the message if they did not fit completely into the previous ConsecutiveFrame. An acknowledged message tran
49、smission that is started with a StartFrame_ACK is always concluded by the receiver with a FlowControl_ACK after the reception of the last frame of the message, which can either be a single StartFrame or a LastFrame (in the case of a multiframe transmission). The request to acknowledge the reception of a block of ConsecutiveFrames via the ConsecutiveFrame_EOB shall always be confirmed by the receiver with a FlowControl frame which indicates the status of the recepti
