Industrial Automation

4 Important Things to Know about            IEEE 802.1 & Time Sensitive Networking

Dr. Oliver Kleineberg

This week a major step forward in Industrial Ethernet is being demonstrated at the Belden Booth at the Hanover Fair (Hall 9, Booth D11) in Germany. It’s a live demonstration of Hirschmann Ethernet switches using the IEEE 802.1 time sensitive networking (TSN) standard to allow the simultaneous transmission of critical control plus best-effort background traffic.


This demo signals the delivery of an  important capability which is deterministic, time-critical packet delivery. It transforms standard Ethernet from an “I’ll get it there as soon as I can” communications technology to one that provides timing guarantees for mission-critical applications.


As someone involved with designing and maintaining industrial networks it’s important for you to understand where industrial Ethernet is going. Time sensitive networking represents the next step in the evolution of dependable and standardized automation technology.


Time sensitive networking will play an important role in communications infrastructure as greater numbers of devices are connected under the Industrial Internet of Things (IIoT) and Industry 4.0 revolution. Read on to learn the 4 important things you need to know about it.



TSN is the next step in the evolution of industrial Ethernet. Shown above is a demonstration of standard Hirschmann RSP35 switches running TSN using IEEE 802.1. Except for firmware modifications, the switches are production units from the factory.


1. It Fulfills the Dream of Standardized, Real-time Industrial Ethernet Networks

While Ethernet is loved for its high bandwidth, interoperability and lower costs of maintenance and support, to date it has not been able to meet fieldbus levels of determinism in packet delivery and timing. Yet, the ability to provide timing guarantees is a key requirement for many mission-critical applications that rely on network communication.


In the early 2000s efforts to create real-time Ethernet did not succeed because different organizations, often centered on a particular technology provider, split up the emerging market with incompatible solutions. In the late 2000s however, our Hirschmann group, a longtime significant contributor to industrial Ethernet standards, noticed a new technology called AVB for Audio and Video Bridging.


AVB enables synchronized playback of audio/video data on different devices and it does it using standardized IEEE 802 Ethernet. While it may not be apparent immediately, the ability to guarantee playback at a certain point in time at different locations in the network is a prime characteristic of a real-time Ethernet protocol.


Hirschmann teamed up with another major player in industrial Automation, Siemens, to initiate a project within IEEE 802.1 to develop AVB further into a standardized industrial protocol. The goal was nothing less than the first vendor-neutral real-time Ethernet based on IEEE 802 specifications alone.


At first the IEEE AVB task group was intrigued but wondered how large a market there would be for its standard. But in 2011, an unlikely ally -- the automotive industry -- adopted Ethernet for car networks, creating a huge market.

For the automotive industry, using deterministic Ethernet makes wiring harnesses simpler, lighter in weight and less expensive. It also makes vehicle electronics more readily adaptable to driver assistance systems and improves the ability of car makers to quickly adopt technology innovations. What industry doesn’t want benefits like that?



The automotive Ethernet market is driving the adoption of time sensitive networking for in-vehicle control and multimedia networks.


2. Today's Time Sensitive Networking Will Work in the Future

Time sensitive networking is not a single technology, but an arrangement of many different technologies. While the first, and one of the most important, parts of TSN has now been released as “IEEE 802.1Qbv – Enhancements for Scheduled Traffic,” other specifications will follow in the next 3-4 years.


The good news is that industrial users and device vendors do not have to wait for all parts of the standard to be released. What is released can be used right away, and additional functionality can be added later, as the specifications are completed. The well-defined IEEE 802.1 standardization process guarantees that each new specification will integrate seamlessly into the existing TSN ecosystem.


Thus, there is no need to wait or hesitate to start working with the next generation of industrial Ethernet – the future of standardized real-time networks is starting now.


3. Time Sensitive Networking Provides Interoperability

Time sensitive networking has mechanisms to enable the coexistence of real-time and non-real-time communication on the same network and it supports fault-tolerance and bandwidth reservation. These capabilities fundamentally enhance basic Ethernet technology.


Standardizing time sensitive networking in IEEE 802 will result in broad interoperability between vendors and the widespread availability of uniform silicon chips that support the technology. This will allow the functionality to permeate beyond industrial and automotive Ethernet markets and make it part of the standard Ethernet feature set – just as bridging and filtering or VLANs did in the past.


4. Time Sensitive Networking is a Foundation Technology for the IIoT

As our Hanover Fair demo shows, IEEE 802.1 time sensitive networking can already be incorporated into standard switches. Over time, it will be built into the chips and software of all of our industrial Ethernet switches.


TSN has already become one of the key enabling technologies for the IIoT and Industry 4.0, for example through standardization efforts with OPC Unified Architecture (UA). By combining TSN standards for lower layers of communication with OPC UA standards for higher protocol layers, the result is an open architecture that can be used to fully network even the most demanding production processes.


From small motion control applications to the flexible intelligent automation networks of the future that encompass entire factories, TSN is a foundation technology that ties everything together. We are proud to have shaped the time sensitive networking standard from its beginning and we are excited to take the next industrial Ethernet networking steps together with our customers.


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