What is Automotive Ethernet?
This page covers Automotive Ethernet basic features and mentions Automotive Ethernet types. It describes standards and anatomies used in automotive ethernet market.
Definition: The ethernet used in automotive vehicles such as cars is known as automotive ethernet.
It is a physical network which is used to connect various components within a car using
wired network. This ethernet type has following features:
• Should support High Data Rate without EMI/EMC problems
• Should meet latency, synchronization and bandwidth requirements.
• Power should be delivered over ethernet cables
• Should support distributed network architecture for communication
• Should work with TCP/IP based protocols
The figure-1 depicts automotive ethernet wherein PHY should be compliant to support data transmission over single twisted pair. PHY gets interfaced with MAC layer using MII (Media Independent Interface). The upper layer protocols such as TCP/IP resides on SoC on microcontroller.
Earlier days it was not possible for ethernet to be used in cars and other automotive vehicles due to
following reasons.
• Ethernet could not support EMI/RFI requirements with 100 Mbps data rate.
RF noise was too much.
• Could not meet low latency requirements in microsecond range.
• It was difficult to control allocation of bandwidth with different stream rate
requirements.
• It was difficult to achieve synchronization between multiple devices.
Standards and Anatomies used in Automotive Ethernet Market
Now-a-days the vehicle consists of advanced driver assistance and control as well as infotainment systems. There are multiple proprietary standards for communication in a car between different vehicle components such as analog signals running on wires, MOST (Media Oriented Systems Transport), flexray, CAN, LIN, LVDS and ethernet technologies. Each component in vehicle has its own wiring and communication specifications.
To meet vehicle specifications new and modification to existing IEEE standards have been developed such as IEEE 802.3 and 802.1.
Following anatomies and standards are used in automotive ethernet market.
The figure-2 depicts estimated progression of automotive ethernet from 1st generation through 3rd generation (year 2020).
• 100Base-T1 (100 Mbps Ethernet over single twisted pair which is used for automotive applications)
• 1000Base-T1 (1000 Mbps ethernet over single twisted pair)
• IEEE 802.1 Audio/Video Bridging (AVB) specifies
priority queueing, time synchronization and traffic shaping to be used in vehicles.
Automotive Ethernet Types
Following are the types of ethernet used in automotive industry.
• One Pair Ethernet (OPEN)
• Energy Efficient Ethernet
• Power Over Ethernet (PoE)
• Gigabit Ethernet (GIG-E)
Refer Automotive Ethernet types➤
ETHERNET LINKS
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