Internet protocols are the new frontier for Ethernet

Ethernet Insights

• Ethernet has become the main communications protocol in manufacturing for a long time and now companies are using Internet of Things (IoT) protocols to improve communications.
• IoT communications has many benefits, but it also needs enhanced security and protocol efficiency because more systems are vulnerable to cybersecurity attacks.
• Time-sensitive networking (TSN) has become a major need because of its ability to deliver precise synchronization.

The wire wars have been over for a long time, and Ethernet has won at all levels: Operational technology (OT), information technology (IT), internet and the cloud. While there are still special cases, it’s clear Ethernet will be the predominant transport for years to come. The benefits of Ethernet are clear: high speed, flexible architectures, and a myriad of troubleshooting tools, plus one backbone for device connectivity.

Industry surveys have shown more products are being connected via Ethernet and while legacy systems will still require proprietary transports, they are on the decline.

The same cannot be said for network communication protocols. There are large pockets of communications applications that benefit from the features and benefits that are associated with a particular protocol. These are often driven by vendor support, but they also fall into feature categories that benefit certain applications.

Most vendor network protocols have support for legacy communications delivering a broad base of support. Some examples are Modbus, simple network management protocol (SNMP) and OPC. These protocols deliver a particular purpose and have varying levels of API sophistication, but are recognized for their general purpose nature and broad applicability.

IoT communication

The world of IoT communications has brought with it additional requirements, specifically the need for enhanced security and protocol efficiency. Newer protocols for Industrial Internet of Things (IIoT) communications include OPC UA, message queuing telemetry transport (MQTT), and advanced message queuing protocol (AMQP). Requirements for IIoT communications generally require “publish and subscribe” communications (Pub/Sub), the ability to support a broker for application subscriptions, and devices that can publish data to that broker on a change or scheduled basis. Most IoT, IIoT and gateway appliance solutions support these communications.

There are protocols that fall into vendor categories such as Profinet, EtherCAT, EtherNet/IP and CC-Link. While these are typically general purpose and designed to handle the broad range of applications supported by that vendor, they have all been made public as industry standards for the market to adopt.  However, most still support 10 to 100 Mb communications. Most major vendors support more than their own solution, often two or three protocols.

TSN and deterministic communication

The advent of new Ethernet specifications, specifically the IEEE 802.1Q features to support time-sensitive networking (TSN), will usher in an opportunity for very high performance, coupled with general purpose communications. This can best be described as finally enabling the combination of IT and OT networks.

TSN delivers microsecond-level time synchronization across devices, enabling them to accurately schedule their communications for deterministic performance. TSN also offers the prioritization of messaging and the shaping of large packets, to assure no blocking of traffic. This combination of features is opening previously closed networks and removing their islands of information. The end user benefits include improved troubleshooting and device management as well as access to more data for performance and quality metrics.

TSN is gaining market share and additional vendors are showing support to ensure interoperability. Several organizations have collaborated and formed an interoperability organization, the TSN Industrial Automation Conformance Collaboration.

The combination of IT and OT networks will likely deliver a resurgence of simple network management protocol (SNMP) as a solution to monitor all devices in a network and no longer only the devices on the IT network.

Thomas Burke is global strategic advisor at CC-Link Partner Association (CLPA), a CFE Media and Technology content partner. Edited by Chris Vavra, web content manager, Control Engineering, CFE Media and Technology, cvavra@cfemedia.com.

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