Author’s Preface

Hello, fellow tech experts! Recently, our company project involves automotive Ethernet, and I was completely clueless at the beginning. After spending over half a month researching materials and testing equipment, I finally figured out the ropes. Thinking that the internet is full of hidden talents, there must be many experts interested in this technology, so I’m writing this post to share my experience while seeking guidance from you all.

Here’s my conclusion upfront: Automotive Ethernet is genuinely great technology, but it has quite a few pitfalls. If you’re working in automotive electronics or interested in connected vehicle technology, I recommend reading this post patiently.

Why Does Automotive Ethernet Exist?

To understand this, we need to start with traditional automotive networks. Previously, cars mainly used CAN bus, LIN bus, and similar technologies, which were painfully slow:

• CAN bus: Maximum 1Mbps, not even enough for a backup camera nowadays
• LIN bus: Even worse at 20kbps, basically just for controlling window up/down functions
• FlexRay: Though capable of 10Mbps, it’s prohibitively expensive for most manufacturers

Modern cars are becoming increasingly intelligent, with various cameras, radars, and sensors generating explosive data growth. A single 1080p camera generates tens of MB of data per second, which traditional buses simply cannot handle. Not to mention applications like autonomous driving, 8K in-vehicle displays, and OTA updates.So automotive Ethernet emerged as a solution – essentially bringing network technology into vehicles, but with specialized modifications.

Core Technology Analysis of Automotive Ethernet

Physical Layer Black Technology

The most impressive aspect of automotive Ethernet is achieving 100Mbps or even 1Gbps using just one pair of twisted wires! This is made possible by Broadcom’s BroadR-Reach technology. While regular Ethernet requires 4 pairs of wires, automotive Ethernet needs only 1 pair, bringing several benefits:

• 30% reduction in harness weight (real money savings for automakers)
• 80% cost reduction (more real money savings)
• Transmission distance up to 15 meters (enough to cover the entire vehicle interior)

Protocol Support: One Network for All

Unlike CAN bus with its specialized nature, automotive Ethernet can simultaneously run multiple protocols:

• DoIP: Vehicle diagnostics, replacing traditional OBD interfaces
• AVB: Audio/video transmission with guaranteed latency and bandwidth
• TCP/IP: Connected vehicle applications, seamless internet integration
• SOME/IP: Service-oriented communication, very promising

This is like a highway where any type of vehicle can travel, much more flexible than dedicated roads.

Real Product Experience Sharing

Speaking of theory, let me share some practical experience. I recently tested several automotive gateway products, including the SV910 5G Vehicle Gateway . This is also our company’s main product currently – you can search for “SV910 automotive gateway” if interested:Key Features:

• 3 x 1000/100BASE-T1 interfaces (these are automotive Ethernet interfaces)
• 2 x traditional 1000/100BASE-TX interfaces
• Support for 5G, WiFi 6, V2X, and many other functions

When I first received it, I wondered why they designed this hybrid configuration. After actual use, I realized we’re in a technology transition period where vehicles have both new devices supporting automotive Ethernet and traditional CAN/Ethernet devices. The hybrid configuration is indeed very practical.Interesting findings during testing:

1. Heat dissipation is crucial – This device operates in -35°C to +75°C temperature range. Summer in-vehicle temperatures often exceed 60°C, which ordinary network equipment simply cannot handle.

2. Thoughtful interface design – Uses M12 aviation connectors, much more robust than regular RJ45, with IP40 protection rating. In the vehicle’s vibration and high-temperature environment, interface stability is truly critical.

3. High functional integration – Not just a gateway, but also integrates edge computing, 5G communication, GPS positioning, and other functions. One device replaces several, which is valuable for space-constrained vehicle environments.

In-Depth Technical Analysis

Time Synchronization: Critical of the Critical

Automotive Ethernet uses IEEE 802.1AS standard for time synchronization with sub-microsecond precision. How important is this? Imagine an autonomous driving scenario: the front camera detects an obstacle while radar confirms the distance. If this data isn’t time-synchronized, the system might make incorrect judgments. At high speeds, even a few microseconds of error could be fatal.

AVB Audio/Video Bridging

AVB technology solves a key problem: how to ensure transmission of critical data during network congestion. Through stream reservation protocol, it reserves bandwidth for important audio/video data, ensuring priority transmission even when the network is busy. This is crucial for automotive applications – you can’t have navigation voice guidance stuttering due to network congestion.

Power Consumption and Supply

Automotive Ethernet supports PoDL (Power over Data Line) technology, enabling power supply to terminal devices through data lines. This design is clever – transmitting both data and power while reducing wiring complexity.

Standardization Status and Industry Chain

Current automotive Ethernet-related standards include:

• IEEE 802.3bw: 100BASE-T1 physical layer standard
• IEEE 802.3bp: 1000BASE-T1 physical layer standard
• IEEE 802.1AS: Time synchronization standard
• IEEE 802.1Qav: AVB standard

Regarding the industry chain, Broadcom leads in technology, providing BroadR-Reach technology. Domestically, communication manufacturers like Huawei and ZTE are also making moves. Among automakers, BMW, Mercedes-Benz, and others are actively promoting adoption.

Development Trends and Personal Views

According to various research reports, the automotive Ethernet market is growing rapidly, with penetration rates expected to reach 80% by 2025. I think this prediction is quite reliable for several reasons:

1. Technology maturity is sufficient – After years of development, automotive Ethernet technology is quite mature, with products entering mass production.

2. Rapidly declining costs – With scaled production, costs are dropping quickly to levels acceptable to automakers.

3. Increasing application scenarios – Applications like autonomous driving, connected vehicles, and OTA updates have exploding bandwidth demands that traditional buses simply cannot meet.

However, I must also provide some perspective: automotive Ethernet won’t completely replace traditional buses. CAN bus still has advantages in real-time performance and reliability, especially for safety-critical applications like braking and steering. The future will likely see multiple networks coexisting, each serving their specific roles.

Pitfall Experience Sharing

I encountered several pitfalls during testing that I’d like to share:

1. Test environment must simulate real vehicle conditions – Vehicle environments are complex with strong electromagnetic interference, high temperatures, and vibrations. Laboratory testing often fails to reveal problems.

2. Compatibility testing is crucial – Different manufacturers’ devices may have compatibility issues, especially with proprietary protocol implementations.

3. Cable quality cannot be compromised – Automotive Ethernet has high cable quality requirements. Cheap cables may cause signal attenuation and increased error rates.

Conclusion

Automotive Ethernet is indeed a very promising technology with great significance for automotive intelligence development. As technical professionals, we need to:

• Stay updated with technological developments: This field changes rapidly with new standards and products emerging constantly
• Focus on practical applications: Can’t just look at theory; must combine with specific application scenarios
• Pay attention to industrial ecosystem: Going it alone won’t work; requires industrial chain collaboration

Finally, I welcome discussion and exchange with all experts, especially those with relevant project experience who can share practical insights. My level is limited, so please feel free to correct any errors in this article!