Ethernet welcomes new growth: Experts' view on automotive Ethernet and AVB technology

Before discussing automotive Ethernet, let’s take a look at the development process and current status of Ethernet. The concept of “The Intergalactic Computer Network” in 1963 is considered to be the origin of the modern Internet; in 1969, “The Advanced Research Projects Agency Network (ARPANET)” was the first network to implement TCP/IP and the origin of the “global Internet”; after more than 50 years of development, Ethernet technology has undergone many technological breakthroughs and innovations, and the transmission media covers optical fiber, twisted pair, wireless, etc., and the bandwidth has reached 10Gbit/s; although Ethernet has made great progress, the inherent characteristics of Ethernet “simpler, faster, and cheaper” have always accompanied the progress of Ethernet. Today, Ethernet has been fully integrated into all people’s lives.

In 2010, the inherent characteristics of Ethernet and the great changes it brought to people's lives attracted the attention of the automotive and automotive electronics industries. The OPEN Alliance (One-Pair Ether-Net) Special Interest Group (SIG) was born to specialize in the research of Ethernet applications in vehicles. In 2015, with the completion of the development and mass production of vehicle Ethernet physical layer chips by chip manufacturers such as NXP and Broadcom, the desire to "get Ethernet on the car" was realized. Vehicle Ethernet still inherits the characteristics of "simpler, faster, and cheaper", and further combines it with the requirements of vehicles. Based on the original commercial or industrial Ethernet protocol, the protocol is developed for the functional characteristics of the vehicle, and the low-cost UTP (Unshielded Twisted Pair) is used as the physical layer medium. The transmission bandwidth of 100Mb/s is 100 times higher than the theoretical bandwidth of the original vehicle network CAN bus. In the future, 1000Mb/s bandwidth will be used. These are all the continuation of "simpler, faster, and cheaper".

In 2013, in-vehicle Ethernet was a new thing for the automotive electronics industry and vehicle manufacturers in China. Most practitioners were on the sidelines regarding the application of in-vehicle Ethernet. Changchun Jingyu Electronics Co., Ltd. conducted research on the application of in-vehicle Ethernet in domestic vehicles and initially established a high-definition audio and video entertainment system based on the AVB protocol.

As an important organization for automotive Ethernet, AVnu also certified the AVB protocol-based system consisting of four high-definition (resolution 1920*1080) displays based on the NVIDIA K1 processor and commercial 100base-TX (ordinary Ethernet cable) media in October 2014, verifying the technical feasibility of AVB protocol, high-definition transmission, and multi-screen interaction. Currently, the more mature solution on the market is the demo car based on UTP (100base-T1) media, which can verify the relevant standards of the automotive Ethernet physical layer.

As automotive Ethernet technology matures, a wide variety of applications emerge. The networking method of automotive Ethernet is relatively simple, and both star topology and linear topology can be used to complete the networking. The star topology is centered on the "switch", and the available communication bandwidth between nodes is higher, and the delay and jitter are smaller. Reducing nodes will lead to the waste of "Switch" ports, and adding nodes requires different "switch" hardware support; the linear topology consists of a "hand-in-hand" method between nodes, which can easily increase and decrease nodes, but the available bandwidth is reduced, and the delay and jitter are increased;

The existing vehicle network architecture is based on the gateway controller as the core of the network. If this network architecture is used, what changes will the in-vehicle network architecture undergo after the application of in-vehicle Ethernet?

Advantages: Increased communication bandwidth between distributed functions. Increased possibility of expanding network segments; Disadvantages: Distributed functions are implemented through different ECUs, which increases complexity. Scalability leads to an increase in the number of connectors in the network part of the ECU;

What impact will the domain control architecture have?

Advantages: good network scalability; from a functional perspective, the entire functional domain can be implemented by a single supplier; Disadvantages: cross-domain functions are more complex; domain control costs increase vehicle costs;

Keep the original network core gateway controller unchanged, and add Ethernet system locally, such as integrating the "Switch" function with the car machine for the infotainment system, expanding the "Switch" function based on the main functions of the original car machine, and expanding the Ethernet rear headrest display and digital amplifier; the original instrument "Switch" can expand surround view, night vision, and digital antenna. Improve the intelligence of the vehicle, reduce the original vehicle wiring harness, optimize the function distribution, and make it possible for Ethernet to be installed in domestic vehicles.