Deterministic Ethernet Explained

Deterministic Ethernet refers to an extended set of capabilities that allow standard Ethernet to be used in real-time, mission critical applications such as Factory Automation, Process Control, and Automobile Networks.

 

Ethernet has traditionally been a "best-effort" network. To allow Ethernet to be deployed in mission critical applications, it is necessary to add specific features including time synchronization, scheduled traffic, ingress policing, seamless redundancy and others.  These features allow network designers to ensure that certain classes of traffic can be delivered on time, every time throughout the entire network topology. 

 

Deterministic Ethernet started in the factory automation market, where large OEMs defined their own methods for adding these capabilities to Ethernet and this has spawned a number of "open standards" that are used in Industrial Ethernet today. 

 

The IEEE standards organization is currently working to add Time Sensitive Networking (TSN) features to standard 802.1 and 802.3 Ethernet to provide deterministic performance.  When this work is completed, it will become practical to deploy standard TCP/IP Ethernet (with the TSN extensions) in real-time, mission critical applications.  However, it is unlikely that the existing industrial protocols will be replaced by TSN.  It is more likely that they will be adapted to make use of the inherent deterministic capabilities provided by TSN.  

 

The goal behind the new TSN standards is to achieve a truly converged network where all classes of traffic can seamlessly coexist.  This would allow mission critical real-time traffic to coexist on the same network as streaming traffic and best-effort traffic.  A major driving force behind the development of these new TSN standards is the emerging Automotive Ethernet market.

 

An important point to note is that the new IEEE standards are based on some of the same basic techniques that have been used in the Industrial Ethernet protocols for many years.  Profinet IRT, for example, employs a scheduled traffic methodology to manage its time critical data.   Techniques such as Innovasic's PriorityChannel technology have pioneered the path to ensuring that Industrial Ethernet devices are immune to network traffic overload conditions in the same way that ingress policing aims to accomplish this within TSN.  For this reason, companies experienced in Industrial Ethernet can apply that experience in enabling new TSN standards to be successfully deployed.

 

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