Robust automotive ethernet testing beyond basic TC8 compliance
Modern vehicles are no longer defined solely by mechanical performance. They are defined by software, connectivity and high-speed data exchange. From ADAS and infotainment to zonal architectures and centralised compute platforms, Automotive Ethernet is at the heart of in-vehicle communication.
Standards such as those defined by the OPEN Alliance and IEEE have allowed scalable Ethernet deployment in vehicles, including 100BASE-T1, 1000BASE-T1 and emerging multi-gig variants. But as bandwidth increases and architectures grow more complex, one thing becomes clear:
Performance alone isn’t enough. Validation must be rigorous, repeatable and statistically meaningful.
At Resillion, we recently completed an extensive OPEN Alliance Automotive Ethernet project for a customer that went well beyond basic compliance. It combined Layer-1 testing, interoperability validation, diagnostics assessment and transmitter electrical performance analysis, supported by custom automation.
Full OPEN Alliance Layer-1 and interoperability scope
The project looked at the OPEN Alliance Automotive Ethernet ECU Test Specification – Layer 1 (TC8), within our custom-built interoperability test suite. This gave us full coverage of both conformance and real-world interoperability scenarios.
It focused on four critical robustness domains:
- Link establishment and wake behaviour – ensuring deterministic start up and network stability
- Interoperability and signal quality reporting – validating behaviour under degraded channel conditions
- Cable diagnostics capability – confirming reliable fault detection
- PHY transmitter electrical performance (PMA) – ensuring signal integrity and electrical compliance
Together, these areas determine whether an ECU will be compliant with the specification.
Testing in detail
Link-up and wake-up behaviour
We validated link establishment behaviour under all required trigger conditions:
- OABR_LINKUP_01 – Link-up time (Power-on Link Partner)
- OABR_LINKUP_02 – Link-up time (Power-on DUT)
- OABR_LINKUP_03 – Link-up time (Wake-up DUT)
Rather than performing isolated checks, these tests were executed across repeated cycles with statistical evaluation to ensure:
- deterministic link establishment
- low timing variation
- alignment with OEM startup and wake-up expectations
In modern architectures like these, milliseconds matter.
Interoperability signal quality indication
To assess robustness under degraded channel conditions, we performed:
- OABR_SIGNAL_01 – Indicated signal quality with decreasing channel quality
- OABR_SIGNAL_02 – Indicated signal quality with increasing channel quality
These tests verify coherence between:
- Artificial channel degradation
- PHY-reported signal quality indicators
- DUT-level diagnostic reporting
This ensures that when the physical layer degrades, the system accurately detects and reports it – a key requirement for production diagnostics and field reliability.
Cable diagnostics validation
We validated the DUT’s PHY cable diagnostic capabilities using controlled fault injection:
- OABR_CABLE_01 – Near-end and far-end open detection
- OABR_CABLE_02 – Near-end and far-end short detection
Reliable fault detection is critical not only for development validation but for vehicle safety. Malfunctioning connections must be detected and reported reliably so drivers and OEMs are aware when systems are not functioning as intended.
PHY transmitter electrical performance (PMA)
The project also covered 100BASE-T1 PMA transmitter electrical tests, including:
- OABR_PMA_TX_01 – Transmitter output droop
- OABR_PMA_TX_03 – Transmit clock frequency accuracy
- OABR_PMA_TX_04 – Power Spectral Density (PSD)
- OABR_PMA_TX_05 – MDI return loss
- OABR_PMA_TX_06 – MDI mode conversion
- OABR_PMA_TX_07 – MDI common-mode emission
- OABR_PMA_TX_08 – Transmitter distortion
These tests validate signal integrity directly at the PHY interface, ensuring compliance with OPEN Alliance and IEEE electrical limits.
Custom automation for faster and more repeatable testing
While OPEN Alliance specifications clearly define what to test, many of these tests, particularly link-up, wake-up, and interoperability scenarios are still executed manually or semi-manually in many labs.
To address this, we developed a custom in-house automation framework that:
- precisely controls DUT and Link Partner power sequencing
- accurately timestamps trigger and link-establishment events
- executes large iteration counts efficiently
- collects statistical metrics (min / max / mean / standard deviation)
- produces structured logs suitable for engineering analysis and reporting
The result:
Reduced execution time, improved repeatability, better traceability and higher confidence in the data delivered to the customer. Automation also removes the limitations of manual testing, enabling more rigorous validation and extended coverage beyond the requirements of the Open Alliance CTS.
Powered by Keysight Automotive Ethernet Solutions
A critical success factor for this project was the use of Keysight Technologies Automotive Ethernet test solutions as the core measurement backbone.
Automotive Ethernet validation, particularly at the PHY and interoperability levels places stringent demands on test equipment. Measurements must be repeatable, standards-aligned and accurate under controlled signal and channel conditions, while still reflecting real-world automotive environments.
Keysight’s Automotive Ethernet portfolio enabled Resillion to:
- perform standards-aligned PHY transmitter electrical measurements (PMA) with high confidence
- execute controlled channel impairment and signal quality scenarios for interoperability testing
- accurately correlate physical-layer impairments with DUT-reported diagnostics
- maintain traceability and repeatability expected by OEMs and Tier-1 suppliers
By using Keysight instrumentation, in combination with Bitifeye’s Valiframe test suite, Resillion ensured that all measurements were performed using industry-recognised reference solutions, reducing ambiguity and increasing confidence in the results delivered to the customer.
Importantly, Keysight’s solutions also provide a clear scalability path toward higher-speed Automotive Ethernet technologies, including 1000BASE-T1 and Multi-Gig Automotive Ethernet (2.5G / 5G / 10G) – which aligned with Resillion’s roadmap for future Automotive Ethernet validation services.
“Cooperation with independent test houses and service providers such as Resillion adds critical value by complementing Keysight’s automated Automotive Ethernet conformance and interoperability (IOP) test solutions with independent validation, additional automation, and expertise. Combined with Keysight’s broad and unique Automotive Ethernet portfolio covering physical media attachment (PMA) Tx, Rx, and channel or link segment physical layer testing all the way up to Layer 7 of the OSI model, this approach gives the industry confidence that products are not only standards compliant, but truly interoperable and production ready.”
Beyond 100BASE-T1
Although this engagement focused on 100BASE-T1, the test architecture and automation were deliberately designed to scale toward:
- 10BASE-T1
- 1000BASE-T1
- Multi-Gig Automotive Ethernet (2.5G / 5G / 10G)
- Future OPEN Alliance and IEEE-based Automotive Ethernet standards
Validation frameworks must evolve as quickly as vehicle architectures do.
Delivering confidence in automotive ethernet designs
As vehicle networks grow in speed and complexity, validation must go beyond checkbox compliance.
Resillion’s approach enables:
- early-stage development validation
- efficient execution of statistically meaningful test campaigns
- confidence in interoperability, diagnostics and electrical robustness
If you’re developing Automotive Ethernet ECUs and need efficient, transparent and technically rigorous validation, we’d be happy to discuss how our approach can support your program.
