Three Things to Know when Designing an Automotive Ethernet Network

It’s common knowledge that Ethernet is ingrained in the enterprise IT and telecommunication networks, but is just starting to heat up in the automotive industry. Since this technology is still in its infancy stage, what should automotive designers focus on when devising the next generation of in-vehicle networks?

Prioritize Automotive Safety Standards

Auto TechnicianDriver and passenger safety is paramount for auto manufacturers. Currently, in-car Ethernet is mainly used for in-vehicle camera feed distribution. But as automotive Ethernet becomes widely adopted, it will have closer contact with steering, braking, and driver assistance systems—and as a result comprehensive testing will be essential to ensure driver safety.

IT has quality of service (QoS) and reliability of service standards for the accurate data transmission across LANs and WANs. However, this is rarely as important as it is in vehicles, where poor QoS could cost lives if critical data isn’t delivered quickly enough. In particular, prioritization and synchronicity will have to undergo rigorous testing to ensure all systems start together and are ready to function. If the network is overloaded, it is essential that first priority is given to safety-critical systems; it’s dangerous impairing brake function for the sake of infotainment.

Account for Legacy Network Technologies

Existing automotive network environments present a few challenges to testing in-vehicle networks. Legacy network technologies like CAN, LIN, MOST and FlexRay are relatively inexpensive and well-suited to specific tasks. Even as BroadR-Reach® Ethernet grows, it’s unlikely that they’ll be going anywhere for some time yet.

BroadR-Reach will therefore have to be tested under ‘real world’ conditions to see how reliably is can cope with automotive-specific network traffic, in a way that generic IT systems are not. Testing for legacy networks will almost certainly require automotive-specific test development.

Develop Performance Test Standards

Adoption of existing performance testing methodologies used in enterprise networks can prove useful to automotive R&D teams, as long as they’re tailored for in-vehicle networks. For example, IT performance tests commonly cover, among other things, jitter, latency, throughput, packet loss, and packet out of order—all aspects that are as important to automotive networks as any other.

These can be tested separately, but the Internet Engineering Task Force RFC-2544 benchmarking methodology gives engineers a shared set of tests that can be automated, speeding up the process. In addition, extensions to IETF RFC-2544 add standards for switch benchmarking, QoS, synchronization, and application playback—all giving a better understanding of network performance.

Mature Ethernet testing standards give new automotive testing regimes a solid foundation to build on, but it can only ever be a foundation.

If you’d like more comprehensive advice on the specifics of testing automotive Ethernet performance, download our new white paper. Join us to discuss automotive network testing on LinkedIn.

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