Commercial vehicle operators have many options available to them for managing their assets. Whether in an on-highway fleet, agricultural / off-road, construction, or military, available real-time vehicle information is growing. While accessing this data via applicable Wide Area Networks (WANs) is commonplace, new technologies are just beginning to develop to take advantage of all of the connectivity possibilities to further aid in delivery of goods and services. As an enabler to expanding these fleet management applications, vehicle on-board networks (commonly referred to as “in-vehicle” or simply “vehicle networks”) are expected to support a growing number of vehicle related technological solutions.
This paper provides background on vehicle networks, including key terminology, an introduction to standards based protocols, and critical SAE vehicle network related standards. While an historical view of vehicle network topologies and a rationale for the very first vehicle networks is summarized, growth applications such as fleet management system use of vehicle network data generated is emphasized.
To provide an understanding of the importance of a vehicle network backbone, a comparison to modern local area networks (LANs) is provided, along with the structure of the data packets or Protocol Data Units (PDUs). Next, standards based vehicle networks supporting Heavy Duty vehicles are described to explain information is conveyed. These standard protocols include SAE
J1708
,
J1587
,
J1939
,
J2534
, CAN (ISO 11898), and ATA/TMC RP1210. In order to illustrate how these standard protocols work, this paper provides a detailed overview of SAE
J1939
including the
J1939
-7 and
J1939
-73 standards, as well as Heavy-Duty On Board Diagnostics (HD OB) standard Messaging and Diagnostics that use
J1939
. The paper describes how these protocols and those related with LAN and WAN networks complement each other to provide end-to-end connectivity to support a variety of fleet management applications.
Next, the promise of leveraging integration of vehicle networks with LANs and Wide Area Networks (WANs) is discussed. While the industry has recently begun the implementation of the aforementioned internetworking, future inter-vehicle networking scenarios will be described, along with proposed standards required for implementation.
Finally, the future for vehicle networking is outlined including opportunities for standards development in the area of security, bandwidth allocation, application-specific vehicle network protocols, and emerging WANs.
