1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J1939/31_201404 SURFACE VEHICLE RECOMMENDED PRACTICE J1939-31 APR2014 Issued 1994
5、-12 Revised 2014-04 Superseding J1939-31 MAY2010 Network Layer RATIONALE This document has been revised with some updates to address some differences between this document and some of the corresponding tests in the SAE J1939-82 document. The references to ISO 11783 within the Foreign Message Transpo
6、rt discussions were removed since ISO 11783 messages are transmitted as standard J1939 messages. FOREWORD The SAE J1939 communications network is defined using a collection of individual SAE J1939 documents based upon the layers of the Open System Interconnect (OSI) model for computer communications
7、 architecture. The SAE J1939-31 Network Layer document defines the OSI Network layer requirements and services that enable electronic control units (ECUs) on one network segment to intercommunicate with other ECUs on different network segments of the vehicle network. The SAE J1939 communications net
8、work is a high speed ISO 11898-1 CAN based communications network that supports real-time closed loop control functions, simple information exchanges, and diagnostic data exchanges between Electronic Control Units (ECUs) physically distributed throughout the vehicle. The SAE J1939 communications net
9、work is developed for use in heavy-duty environments and suitable for horizontally integrated vehicle industries. The SAE J1939 communications network is applicable for light-duty, medium-duty, and heavy-duty vehicles used on-road or off-road, and for appropriate stationary applications which use ve
10、hicle derived components (e.g. generator sets). Vehicles of interest include, but are not limited to, on-highway and off-highway trucks and their trailers, construction equipment, and agricultural equipment and implements. The physical layer aspects of SAE J1939 reflect its design goal for use in he
11、avy-duty environments. Horizontally integrated vehicles involve the integration of different combinations of loose package components, such as engines and transmissions, that are sourced from many different component suppliers. The SAE J1939 common communication architecture strives to offer an open
12、 interconnect system that allows the ECUs associated with different component manufacturers to communicate with each other. SAE INTERNATIONAL J1939-31 Revised APR2014 Page 2 of 35 TABLE OF CONTENTS 1. SCOPE 3 2. REFERENCES 3 2.1 Applicable Documents 3 2.2 Related Publications . 4 3. DEFINITIONS AND
13、ABBREVIATIONS . 4 3.1 Definitions . 4 3.2 Abbreviations 6 4. NETWORK LAYER DESCRIPTION . 6 4.1 General 6 4.2 Reasons for Multiple Networks . 6 4.3 Network Topology . 7 5. NETWORK INTERCONNECTION ECUS . 10 5.1 Types of Network Interconnection ECUs 10 5.2 Message Forwarding Transit Delay Requirements
14、. 13 5.3 NIECU Conformance (Minimum Requirements) . 13 5.4 NIECU Suitability Criteria 14 6. NETWORK INTERCONNECTION FUNCTIONS . 14 6.1 Message Forwarding . 14 6.2 Message Filtering 14 6.3 Address Translation 15 6.4 Protocol Translation 15 6.5 Database Management . 15 6.6 Tunneling (Foreign Message T
15、ransport) . 16 7. NETWORK INTERCONNECTION ECU DATABASE MANAGEMENT MESSAGE . 19 7.1 General Network Message Requirements 19 7.2 Network Message Definition . 19 7.3 Message Filter Database Services (N.MFDB) 20 7.4 Network Topology Information Services (N.NT) . 23 7.5 NIECU General Parametric Data Serv
16、ices (N.GP) . 25 7.6 NIECU Specific Port Pair Parametric Data Services (N.SP) 26 7.7 Network Message Data Definitions . 28 8. NOTES 32 8.1 Marginal Indicia . 32 APPENDIX A STATUS AND STATISTICS PARAMETER DEFINITIONS 33 FIGURE 1 TYPICAL SAE J1939 VEHICLE NETWORK FOR TRUCK AND BUS . 8 FIGURE 2 TYPICAL
17、 SAE J1939 VEHICLE NETWORK FOR AGRICULTURAL APPLICATIONS . 9 FIGURE 3 FOREIGN MESSAGE TRANSPORT EXAMPLE 1 - LOGICAL MODEL 17 FIGURE 4 FOREIGN MESSAGE TRANSPORT EXAMPLE 1 - MESSAGING SEQUENCE 17 FIGURE 5 FOREIGN MESSAGE TRANSPORT EXAMPLE 2 18 FIGURE 6 FOREIGN MESSAGE TRANSPORT EXAMPLE 3 18 FIGURE 7 N
18、ETWORK MESSAGE (PGN 60672) DEFINITION . 20 FIGURE 8 EXAMPLE OF MESSAGE FILTER DATABASE ACCESS . 21 TABLE 1 NETWORK MESSAGE CONTROL BYTE VALUES 28 TABLE 2 PORT NUMBER ASSIGNMENTS 29 TABLE 3 FILTER MODE VALUES . 30 TABLE 4 NIECU STATUS AND STATISTICS PARAMETER NUMBERS. 31 TABLE A1 NIECU TYPE ASSIGNMEN
19、TS . 35 SAE INTERNATIONAL J1939-31 Revised APR2014 Page 3 of 35 1. SCOPE SAE J1939-31 Network Layer describes the requirements and services for Network Interconnection ECUs (NIECU) that enable electronic control units (ECUs) on a network segment to intercommunicate with other ECUs on different netwo
20、rk segments of the vehicle network. This document defines various types of NIECUs. The information in this document applies only to ECUs that are intended to provide networking services. It is not necessary for an ECU to provide any of these services in order to be compliant with the SAE J1939 proto
21、col. 2. REFERENCES 2.1 Applicable Documents General information regarding this series of documents is found in SAE J1939. The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 S
22、AE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J1587 Electronic Data Interchange Between Microcomputer Systems in Heavy-Duty Vehicle Applications SAE J1922
23、Powertrain Control Interface for Electronic Controls Used in Medium- and Heavy-Duty Diesel On-Highway Vehicle Applications SAE J1939 Recommended Practice for a Serial Control and Communications Vehicle Network SAE J1939-21 Data Link Layer SAE J1939-71 Vehicle Application Layer SAE J1939-81 Network M
24、anagement 2.1.2 ISO Publications Available from American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ISO 11783 Tractors and Machinery for Agriculture and Forestry Serial Control and Communications Data Network ISO 11898-1 Road vehicles
25、 - Controller area network (CAN) Part 1: Data link layer and physical signaling ISO 11992 Road Vehicles Interchange of digital information on electrical connections between towing and towed vehicles ISO 15765 Road Vehicles Diagnostics on Controller Area Network (CAN) SAE INTERNATIONAL J1939-31 Revis
26、ed APR2014 Page 4 of 35 2.2 Related Publications The following publications are provided for information purposes only and are not a required part of this SAE Technical Report. 2.2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-73
27、23 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J1939-01 Recommended Practice for Control and Communications Network for On-Highway Equipment SAE J1939-02 Agricultural and Forestry Off-Road Machinery Control and Communication Network 2.2.2 IEEE Publication Available from I
28、nstitute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, NJ 08854-4141, Tel: 732-981-0060, www.ieee.org. ANSI/IEEE STD.802-1D Local Area Networks: Media Access Control (MAC) Bridges 3. DEFINITIONS AND ABBREVIATIONS See SAE J1939 for definitions that are not defined in this docume
29、nt. 3.1 Definitions 3.1.1 Address Space The allowable range of Addresses on a particular subnetwork. The address space is continuous for the set of network segments when connected by a repeater or bridge. The address space is separate for each network segment when connected by a router, which means
30、the same address can be used by a different CA on each side of the router. When segments have separate address space, CAs on one segment cannot directly address individual CAs on the other segment. 3.1.2 Database A general reference to the collection of data in some NIECUs that defines the operation
31、 of the internetworking functions and contains status and statistical data about the NIECU internetworking activity. Examples of operation data might be a list of PGNs for filtering messages forwarded between network segments or the filtering mode to apply. Examples of status and statistical data mi
32、ght be the maximum size for the filter database or the average number of messages forwarded per second. The term can be used in reference to the data collection as a whole or in reference to a specific subset of the data collection, such as the data governing the transfer of messages between a pair
33、of ports on the NIECU. 3.1.3 Foreign Message Transport Foreign Message Transport describes the functionality for transferring non-SAE J1939 messages (i.e. foreign messages) over an SAE J1939 network in an SAE J1939 compatible manner. Using special SAE J1939 PGNs assigned by SAE J1939, the non-SAE J1
34、939 message is encapsulated into the data field of the special SAE J1939 PGN which can then be transported over the SAE J1939 network. The definition for how a Foreign Message is encapsulated into the data field of these special SAE J1939 PGNs is defined elsewhere, typically within the industry stan
35、dard documents associated with the special SAE J1939 PGN, such as within ISO 11992 or ISO 15765. The addresses associated with the SAE J1939 messaging and any addressing that is a part of the foreign message are considered separate address spaces. SAE J1939 source addresses shall be claimed and used
36、 when sending and receiving these special PGNs over an SAE J1939 network. Any addressing that is a part of the foreign message will need to be included in the encapsulated data field content if necessary. SAE INTERNATIONAL J1939-31 Revised APR2014 Page 5 of 35 3.1.4 Network The complete collection o
37、f one or more physical communication links, or network segments, on a vehicle that may be connected together physically and/or virtually through network interconnection devices. 3.1.5 Network Interconnection ECU (NIECU) An ECU that provides interconnection of messages between one or more network seg
38、ments. The standard types of NIECUs are repeater, bridge, router, and gateway. 3.1.6 Port The connection point on a controller to the network. A NIECU has two or more ports connected to different network segments. 3.1.7 Port Pair A title that describes the two ports being discussed and the direction
39、 of data flow (from-to) 3.1.8 Segment A physical section of a vehicle communications network. The physical section is bounded by the ECUs connected to it and any NIECUs. All of the ECUs on a segment “see“ the signal at the same time (i.e., there is no intermediate device between different sections o
40、f the network). Multiple segments can be connected together by NIECUs. 3.1.9 Subnetwork (Subnet) A subset of the vehicle network consisting of one or more network segments connected together. Subnetworks may include: Tractor, Trailer, Implement, and Braking System. Subnetworks are typically separate
41、d by a bridge, router, or gateway to help minimize bus traffic on each segment. Collectively the subnetworks are the Vehicle Network. 3.1.10 Transit Delay The amount of time delay incurred when an NIECU forwards a received message from one network onto another network. The time between the moment th
42、e message is received at an NIECU and the moment that same message is transmitted out by that NIECU. 3.1.11 Transparent The characteristic of an NIECU and its internetworking functions that are performed in such a way that the actions and operations are not perceived by other ECUs on the vehicle net
43、work. If the NIECU is transparent, then the other devices on the network do not need to know of the presence of the NIECU, and the NIECU network functions and services take place without any visible effects (i.e., invisible). A bridge NIECU between a tractor subnet and trailer subnet is characterize
44、d as transparent if ECUs on the tractor subnet and ECUs on the trailer subnet can communicate with one another without knowledge of the bridge involvement in forwarding some messages between the network segments, filtering other messages, and possibly changing the data rate between the networks. 3.1
45、.12 Tunneling The networking function of encapsulating one network protocols message within messages of a second network protocol and carried over the second network. The network message that is tunneled is all or part of the payload of the messages carried on the other network. SAE INTERNATIONAL J1
46、939-31 Revised APR2014 Page 6 of 35 3.2 Abbreviations CA Controller Application ECU Electronic Control Unit NIECU Network Interconnection ECU OEM Original Equipment Manufacturer PGN Parameter Group Number SPN Suspect Parameter Number 4. NETWORK LAYER DESCRIPTION 4.1 General The Network Layer defines
47、 the requirements and services for NIECUs, which are the electronic devices that provide intercommunications between different segments of a vehicle wide SAE J1939 network. An NIECU is an ECU with more than one port, or network connection, with a Controller Application that functions to transfer inf
48、ormation from a port connected to one network segment to a port connected to another network segment. When the vehicle network has multiple segments and it is necessary to transfer information between devices on separate network segments, then an NIECU is needed to provide for the transfer of messag
49、es from one segment to another. The type of NIECU required between two segments of the network depends upon the needs of the system and the protocol of each network segment. For example, a bridge may isolate two segments of media and the bus traffic on each, but the network is still considered “one“ network in terms of address space and identifiers. There are several different types of NIECUs, each providing different internetworking f
