Fundamentals of Design: Networking under Pressure of Time
Time-Sensitive Networking Transforms Traditional Ethernet for Real-Time Applications
Time-Sensitive Networking (TSN) is an enhancement of standard Ethernet technology, designed to cater to the specific needs of real-time applications such as industrial automation, robotics, aerospace, and military systems. Unlike traditional Ethernet, which emphasizes flexibility and scalability but cannot guarantee strict timing, TSN introduces precise time synchronization, scheduled traffic, and traffic prioritization to ensure time-critical data is delivered reliably and on time.
Key aspects of TSN include Precision Time Synchronization, Scheduled Traffic and Traffic Scheduling, Frame Preemption and Traffic Shaping, Integration with Power over Ethernet (PoE), and its adaptation for specialized fields like aerospace and military networks.
Precision Time Synchronization is achieved through IEEE 802.1AS, an evolution of the IEEE 1588 Precision Time Protocol, which synchronizes all network devices to microsecond accuracy. This ensures all devices operate in lockstep, eliminating jitter and time drift common in conventional Ethernet.
Scheduled Traffic and Traffic Scheduling are facilitated by IEEE 802.1Qbv and other TSN standards. These networks schedule when specific traffic classes can transmit, akin to traffic lights and dedicated lanes, allowing guaranteed bandwidth and bounded latency for critical data flows.
Frame Preemption and Traffic Shaping enable TSN to interrupt lower-priority traffic with high-priority frames to ensure timely delivery even under network congestion. TSN also uses methods to manage and reduce latency and buffering delays.
TSN is compatible with PoE networks, allowing simultaneous delivery of power and deterministic data over a single Ethernet cable, simplifying deployments in industrial contexts.
Differences between TSN and traditional Ethernet are evident in areas such as timing, latency, traffic prioritization, jitter, suitability for real-time demands, and standards. TSN offers precise time synchronization, low, deterministic, bounded latency, strict scheduled traffic and frame preemption, minimized jitter, and is designed for real-time critical applications, while traditional Ethernet is more flexible but nondeterministic in nature.
TSN is not limited to wired networks. It is being integrated with wireless technologies like 5G, where 5G networks act as logical TSN bridges, preserving these deterministic properties over wireless links to extend TSN’s benefits to mobile or distributed industrial systems.
TSN is used in various fields, including the Internet of Things (IoT), test and measurement purposes, and the automation of various systems. It is also a topic of discussion in blending it with other protocols like DDS, OPC UA, and communications for real-time applications.
In conclusion, TSN builds on Ethernet by adding precise time synchronization, scheduling, and traffic management to meet the stringent latency and reliability needs of next-generation industrial, aerospace, and military applications, differentiating it fundamentally from conventional Ethernet's flexible but nondeterministic nature.
References:
[1] IEEE. (2021). Time-Sensitive Networking (TSN). Retrieved from https://www.ieee.org/standards/get_standards/detail/802.1Qbv-2021
[2] IEEE. (2018). Time-Sensitive Networking (TSN) – Overview. Retrieved from https://www.ieee.org/standards/get_standards/detail/802.1Qbv-2018
[3] IEEE. (2021). IEEE Std 802.1DP-2021, IEEE Standard for Local and Metropolitan Area Networks – Bridges and Remote Bridges II – Amendment 3: Time-Sensitive Networking (TSN) Profile for Aerospace and Defense Bridging. Retrieved from https://ieeexplore.ieee.org/document/9453388
[4] IEEE. (2021). IEEE Std 802.1Qbv-2021, IEEE Standard for Local and Metropolitan Area Networks – Amendment 1: Time-Sensitive Networking (TSN) Overview and Architecture. Retrieved from https://ieeexplore.ieee.org/document/9453398
[5] IEEE. (2020). IEEE Std 802.1Qbu-2020, IEEE Standard for Local and Metropolitan Area Networks – Amendment 1: Time-Sensitive Networking (TSN) for Wireless Access. Retrieved from https://ieeexplore.ieee.org/document/9009682
Data-and-cloud-computing technologies could leverage Time-Sensitive Networking (TSN), a technology that enhances standard Ethernet, to manage time-critical data more efficiently in real-time applications. TSN, with its integration of Precision Time Synchronization, Scheduled Traffic, and Traffic Scheduling, among other features, offers a promising solution for reducing latency and buffering delays, crucial in modern data-intensive systems.
