What is TSN?
TSN is an extension of standard Ethernet, operating at Layer 2 of the OSI model. It enhances Ethernet by introducing determinism to data communication, addressing key issues such as latency and jitter, which previously hindered Ethernet’s adoption in industrial settings. TSN offers mechanisms that ensure predictable and reliable data delivery, critical for machine control, motion systems, and other time-sensitive industrial processes.
TSN allows multiple types of network traffic, including industrial Ethernet protocols and conventional IT traffic, to share the same network. This convergence reduces the need for separate systems, leading to lower costs and improved productivity.
It’s important to note, though, that TSN primarily acts as a “pipe” for transmitting data in a deterministic manner. It does not manage higher-level application functions such as safety protocols or motion control. Therefore, existing industrial protocols will still be essential to handle these specific tasks alongside TSN.
TSN technology operates at Layer 2 of the OSI seven-layer model, as defined by ISO/IEC 7498.
The Importance of Bandwidth in TSN Networks
TSN not only provides deterministic performance but also optimizes the use of network bandwidth. As the demand for data increases with the growth of Industry 4.0 applications, efficient bandwidth utilization becomes essential. TSN prioritizes traffic based on its importance, ensuring that critical data flows without interruption, even in congested networks.
Historically, many industrial Ethernet technologies operated at 100 Mbps, which could limit performance as data volumes grew. TSN, however, is designed to work with higher bandwidths, such as 1 Gbps, which allows more data to flow across the network without sacrificing performance. This shift to gigabit Ethernet, combined with TSN’s prioritization features, ensures that industrial networks can handle increased traffic without compromising the delivery of critical data.
Evolution and Standardization of TSN
TSN is defined by the IEEE 802.1 standards, which are continuously evolving to meet the needs of modern industrial applications. The development of TSN is driven by a focus on providing deterministic performance and convergence, enabling diverse types of network traffic to coexist while maintaining transparency and reliability.
One of the key aspects of TSN’s evolution is its backward compatibility with existing Ethernet technologies. This ensures that as TSN standards continue to advance, earlier Ethernet devices can still operate within the same network. This compatibility provides businesses with a migration path that supports both current and future networking needs without rendering their existing infrastructure obsolete.
The ongoing development of TSN standards is further supported by the IEC/IEEE 60802 project, which focuses on standardizing the use of TSN in industrial automation. This initiative ensures that TSN will continue to address the demands of industrial applications, making it a future-proof investment for companies looking to optimize their network infrastructure.
The IEEE Standards Involved in TSN
- Time Synchronization (IEEE 802.1AS): TSN achieves determinism by synchronizing the time across all devices on the network. This ensures that every operation is coordinated down to sub-microsecond precision, allowing critical processes to occur exactly when needed. Time synchronization minimizes time drift, reducing delays and ensuring consistent data transfer.
- Traffic Scheduling (IEEE 802.1Qbv): Enhancements for Scheduled Traffic: After achieving synchronized timing across the network, IEEE 802.1Qbv introduces “time-aware shapers” that allocate specific time slots for different types of network traffic. These slots prioritize traffic based on its importance. For instance, critical signals like an emergency stop command would be prioritized over less urgent data, such as video frames from a machine vision system, ensuring the timely delivery of high-priority information.
- Frame Preemption (IEEE 802.1Qbu/802.3br): This feature allows critical data frames to preempt lower-priority frames, ensuring that urgent information bypasses less critical traffic. Frame preemption helps maintain real-time performance in demanding industrial applications where even a slight delay can cause system disruptions or inefficiencies.
- Traffic Shaping (IEEE 802.1Qav): TSN uses traffic shaping to regulate the flow of data through the network, ensuring that critical traffic is prioritized and bandwidth is used efficiently. By controlling the rate at which data packets are transmitted, traffic shaping prevents network congestion and maintains smooth data flow, improving the overall performance of the network.
- Redundancy (IEEE 802.1CB): TSN enhances network reliability by providing seamless redundancy. It allows data to be sent over multiple paths, ensuring that if one path fails, the data can still be delivered through another route. This feature is crucial in industrial settings where network failure could lead to costly downtime or safety hazards.
IEEE 802.1Qbv enables the creation of specific time slots for network traffic queues, determining when each type of traffic can access the network. In this scenario, four time slots are allocated to eight queues, with higher-numbered queues being given priority within their respective slots.
RT-Labs’ Positioning Towards TSN
At RT-Labs, we recognize the transformative potential of TSN for industrial networking, but we also understand that its widespread adoption will take time. While TSN offers significant advantages in terms of determinism, efficiency, and network convergence, the transition to this new technology requires careful planning and investment in infrastructure upgrades.
Many of our clients currently rely on established industrial Ethernet protocols like PROFINET and EtherCAT, which continue to serve their operational needs effectively.
Our strategy is to provide comprehensive support for both current and emerging technologies. We help clients optimize their networks today, while also positioning them for the future. By partnering with RT-Labs, companies can confidently navigate the industrial networking landscape, knowing they are equipped to handle both present and future demands.