# A Perspective on Ethernet in Automotive Communications--Current Status and Future Trends
## 3 Ethernet for Automotive Communications  
Automated driving poses new challenges, as it requires correct perception of the surrounding environment in any driving condition. To achieve this result, not only are many more sensors than in current ADAS needed, but such sensors are also of different types, such as radars, ultrasonic sensors, LiDARs, and video cameras. Given the high number of sensors and the bandwidth requirements of some of them (e.g., cameras, LiDARs), high-bandwidth automotive-grade networks are required.  
Ethernet technology is a suitable candidate, as it offers high bit rates of up to 10 Gbps. Moreover, automotive-grade Ethernet Physical layers able to correctly operate in harsh conditions under high electromagnetic radiation and thermo-mechanical stress are standardized, and most of them are already available. Consequently, Automotive Ethernet represents the main in-car networking solution for current and future automotive architectures. The main reasons that originally triggered interest in Ethernet for automotive communication were the higher bandwidth provided as compared to other in-car networks, the support offered to the Internet Protocol (IP) stack, and its wide use and acceptance, thanks to IEEE standardization and openness [26]. Moreover, the large community of developers and users generated positive market expectations in terms of a high number of good-quality chips available at low development and manufacturing costs.  
Thanks to the IEEE standardization, Automotive Ethernet is nowadays unanimously considered the solution for achieving a homogeneous in-vehicle network that will replace the multiple small networks connected via gateways that are currently used in cars.  
A broad range of data rates for automotive usage is available, i.e.,  
* 100 Mbps (standardized as IEEE 802.3 bw-2015);
* 1 Gbps (standardized as IEEE 802.3 bp-2016);* 10 Mbps (standardized as IEEE 802.3 cg-2019, also known as 10 Base-TIS);
* 2.5, 5, and 10 Gbps (standardized as IEEE 802.3 ch-2020, also known as Multi-Gig Automotive Electrical Ethernet PHY).  
The migration from domain-based to zonal architectures, which use Ethernet links to support autonomous operation, demands data rates higher than 10 Gbps. Consequently, the IEEE standardization project \"Greater than 10 Gb/s Electrical Automotive Ethernet\"-P802.3 cy ([[https://standards.ieee.org/project/802_3](https://standards.ieee.org/project/802_3) cy.html]([https://standards.ieee.org/project/802_3](https://standards.ieee.org/project/802_3) cy.html) (accessed on 23 December 2022)) that addresses 25, 50, and 100 Gbps rates is on its way to being approved in 2023.  
However, Ethernet was not designed with real-time traffic in mind, but as a best-effort network. As a result, special mechanisms had to be introduced to provide real-time traffic with bounded delays that can be analytically obtained through timing analysis [27; 28; 29]. Early studies in the literature proposed applying traffic-shaping techniques to bound the interference of best-effort traffic on real-time flows over Ethernet networks in order to provide statistical guarantees on the timely delivery of real-time frames [7; 30; 31]. Later on, Credit-Based Shaping (CBS) was adopted by the AVB family of standards [32] to limit the traffic bursts of real-time flows so that they could be provided with bounded latency over Switched Ethernet. While this is very well suited to the needs of audio/video traffic, CBS is not suitable for supporting safety-critical control traffic, as shaping can delay the frame transmissions, thus introducing transmission jitter. To handle time- and safety-critical traffic, the TSN family of standards [3] introduced time-aware shaping in the IEEE 802.1Q switches.  
In the following subsection, the main features of the AVB standards are discussed.