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Vehicle communication introduction

来源：公众号“汽车安全前瞻研究”

2020-05-12

1767

[Author]

Samuel WENG

This article will introduce the basic information towards vehicle telecommunication basic categories.

First:Open System Interconnection Reference Module

we have to start the whole article from OSI model. and following is the their introduction and definitions.

(1)Application layer, which supports for application layer interface, so that another software can communicate with. some protocols are famous, like HTTP,HTTPS, FTP, TELNET, SSH etc;

(2)Presentation layer, which can change the data and system format so that the format can be integrated with the receiver port and those format and system canbe suitable for transportation;

(3)Session layer, which does not participate in specific transmissions, which provides mechanisms for establishing and maintaining communication between applications, including access verification and session management; informationhere is called message;

(4)Transport layer, the data unit called packets. within TCP it is called segments, and in UDP, we called it as datagrams. Within this layer, we have to check and ensure that data unit fragmentation, out-of-order packets, and other dangers that may occur during transmission must be tracked, but some lostmessages might not be aroused attentively;

(5)Network layer, which ensure the suitable routers and connection joints, so that data can be transmitted in time. The network layer composes the frames providedby the data link layer into a data packet. The network layer header is encapsulated in the packet, which contains the logical address information-thenetwork address of the source site and destination site addresses.

(6)Data link layer, which will operates for ethernet etc protocols.

(7)Physical layer, many equipments, including hardware sensors, actuators those contribute to the physical.

we can set some example protocols and information listed as following here, for OSI each layer:

Second:TCP/IP protocol suite

present the vehicle communication will be more based on TCP/IP protocol suite rather than in CAN, no matter in ethernet or flexray or others, and we often called inthis suites.

Many communication and SEOOC like AutoSAR will includes one stack mainly for TCP/IP,they are mainly called TCP/IP stacks.

we will make mapping from OSI layer to TCP/IP layer, as following:

And for each layer, some example protocol listed as following:

Third:IEEE802

IEEE group try to establish the LAN and Metropolitan Area Network, and following IEEE group i had adopted from CSDN, author 'NDSC的我' as simplification of IPS:

Final:AutoSAR related TCP/IP Stack

we based on AutoSAR, and describe the TCP/IP stack inside this famous SEOOC communication stack.

inside the communication management, we have following TCP/IP from drive, toabstraction, towards service, and to RTE, here listed had been adopted partlyfrom AutoSAR manuals:

①data flow: