Automotive Ethernet Testing Made Easy

Ethernet is being used to move the world’s data, from planes, trains and automobiles to industrial motor control, autonomous vehicles and the Internet of Things (IOT). The demand to create systems of systems has never been greater, and brings in new challenges to development engineers. They need to gain knowledge on new technologies and on techniques for testing in order to design high speed networks for safety-critical signals. Designing a quality product on time and under budget can be difficult if not impossible without the proper expertise. The key to succeed in this challenge is to uncover product defects in early design stages. But how can this be done without all of the other members in the network? The answer is testing using AUTOSAR, OPEN Alliance or Automotive Avnu profiles test suites to ensure conformance to industry standards.

HARMAN, a leading automotive supplier for Infotainment and Car Audio worldwide, relies on Spirent automated test solutions to ensure high quality, standards compliant products. HARMAN is using the OPEN Alliance SIG Conformance Test Suite Pack for in-car network tests.

 ?We are testing Automotive Ethernet, the TCP/IP protocol family, and various other automotive protocols like SomeIP, AVB for Infotainment control devices like amplifier, head units, telematic modules and more“, says Mr. Eisinger, Qualification Engineer at Harmans Compliance Tests Center. ?If these tests pass, we can guarantee to our customers that those protocols are implemented correctly. Spirent’s OPEN Alliance test solution helps us to ensure the interoperability of ECUs from different vendors, which is a crucial requirement to meet quality and security standards. We have already been using the test automation platform TTworkbench (which is the platform behind the OPEN Alliance SIG Test Suite Pack) right from the start for testing our MOST (Media Oriented Systems Transport) protocol products. We know TTworkbench well, and we are very pleased with its user-friendly handling and with Spirent's fast and competent support.”

Spirent has 25 years of Ethernet development experience and has shaped many of the industry standards used in existence today.

TSN, Evolving Ethernet to address Low Latency Applications

TSN specifications are defining ways to enable zero congestion loss of time-critical data flows. But loss due to congestion is only half of the issue, as network designers and architects also must measure worst-case end-to-end latency within the network. Latency measurements must also consider primary and redundant flows during fault recovery conditions. This is to be able to measure normal vs redundant data path flows in a live network because it is extremely critical to industrial motor control applications. Using the Spirent emulated devices, you can quickly check the Best Clock Master Algorithm (BCMA) inside real devices on the network to ensure they recover from faulted conditions.

Testing the network with a mix of real devices and Spirent’s Emulated Devices with gPTP functionality will enable designers to find out what scenarios help them to optimize and check network traffic to ensure no loss of time-critical data flows. This is achieved using Spirent embedded counters and timers:

Over 40 measurements tracked in real-time for each received stream including:

1.      Advanced sequencing: In-order, lost, reordered, late and duplicate

2.      Latency: Avg, min, max and short-term avg; first/last frame arrival timestamp

3.      Latency modes: LILO, LIFO and FIFO

4.      Data integrity: Generate Errors: IP checksum, TCP/UDP checksum, frame CRC, embedded CRC and PRBS bit errors

5.      Histograms: Jitter, Inter-arrival, Latency, Sequence

Automated Summary of Timing and Synchronization for IEEE 802.1 – gPTP  

1.      IEEE802.1as Clock Results

2.      IEEE802.1as Time Properties Results

3.      IEEE802.1as Clock Sync Results

4.      IEEE802.1as Parent Clock Info Results

5.      IEEE802.1as Message Rate Results

6.      IEEE802.1 State Summary Results

Impairment / Error injection - Timing and Synchronization for IEEE 802.1 – gPTP

As you are deploying a time-aware network we must take into consideration timing errors. The two main contributors to timing errors are the accuracy of the correction field and the peer delay calculations for each member in the network. Do they reflect the actual delay experienced by the sync messages? Here is a break of possible errors:

Variable Errors

o Quantization errors in time stamps

o  Synchronization/rounding errors in local DUT clocks

o  Phase noise in oscillators

Fixed Errors

o  Asymmetric delays in physical layer ie: time stamp type and point

o  Cable lengths between forward and reverse paths

 In a typical device under test the application functionality turnaround time can and will impact the downstream path delay calculation when internal DUT hardware and software resources are shared between the application functions and network communications.