Time-sensitive networking (TSN) refers to the family of standards defined by the IEEE 802.1 task group to enable the best data delivery for time-sensitive traffic in converged networks. For manufacturing, TSN brings determinism to standard Ethernet networks.
Recent tests of TSN conducted by Avnu Alliance (a community creating an interoperable ecosystem of low-latency, time-synchronized, highly reliable networked devices using open standards) have shown that manufacturers using robotic control and industrial automation technologies can deliver faster, safer and more reliable operations even while applying TSN capabilities over wireless links.
Avnu Alliance members tested TSN capabilities of time synchronization (802.1AS) and traffic shaping (802.1Qbv) over Wi-Fi in industrial automation applications. During testing, a remote-controlled robotic arm was made to perform several fine manipulation tasks demonstrating the use of time synchronization and time-aware scheduling capabilities.
Avnu members observed that, without the 802.1Qbv capability, this task was severely impacted by competing traffic. When the TSN capability was enabled, the arm successfully completed the manipulation task even when competing traffic was present.
The status of robot control actuation and gripper were consistently delivered over the wireless link, with most actuation commands arriving within 2 milliseconds (msec) of the previous sample.
According to Avnu Alliance, this demonstrates TSN’s ability to ensure smooth, reliable performance.
In industrial automation applications, responsiveness to control signals must be near instantaneous, especially for safety-critical data, such as emergency stop signals. During testing, the 802.1Qbv traffic shaping capability was used to schedule a time-sensitive queue to open while other queues closed to avoid conflict with high priority traffic. Measuring the end-to-end latency of the time critical traffic when background traffic was present, the lowest average latency was 1.1 msec, with a bounded latency of 2 msec.
Avnu Alliance said this demonstrates that wireless TSN ensures high priority traffic benefits from low latency, resulting in a faster response time and safer automated operations.
“Advances in wireless technologies hold the potential to transform industrial applications, however low the latency and high the reliability requirements are,” said Dave Cavalcanti, Avnu Alliance president and chair of the wireless TSN working group.
To ensure interoperability, the Avnu Wireless TSN working group is also developing test specifications for TSN over Wi-Fi. Keysight’s automated Wi-Fi compliance package, based on the Avnu TSN test plans, will help Avnu members and test houses advance the TSN Wi-Fi ecosystem.
"Validation of TSN standards are increasingly important to ensure that network devices work together at the component level," said Ram Periakaruppan, vice president and general manager of Keysight's Network Test and Security Solutions group. As a member of the Avnu Alliance, Keysight (a supplier of network test and security technologies and services) plays a key role in standardizing test methodologies for TSN over Wi-Fi.
See the full methodology and results of these experiments in the Wireless TSN: Tests and Use Cases Demonstration with Wi-Fi whitepaper.
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