To test the interoperability of devices from different manufacturers, there are several testbeds - such as the Industrial Internet Consortium - or the LNI testbed in Augsburg. Is it enough to rely on such testbeds for interoperability?

Walter: Testbeds and plugfests can be used to create practical systems that can be used to detect any problems at a very early stage, otherwise these problems might only occur during customer implementation. And yet: testbeds and plugfests can only cover part of the necessary work - they can never replace the necessary conformity tests. In other words, the knowledge gained from the ongoing testbed activities must lead to conformance tests and, if necessary, the existing standards must be revised. The interoperability workshop held by the Industrial Internet Consortium together with Avnu is a good example of how the problem can be tackled:
In a week-long meeting, we focused on using the Manufacturing Testbed to examine the use of TSN for flexible manufacturing and work on the configuration of these systems. Through Avnu's collaborative agreements with many organizations, including the IIC and the OPC Foundation, such findings can be communicated efficiently to generate a faster process for establishing an open, interoperable ecosystem.

So testbeds alone are not enough!

Walter: Testbeds enable several providers to test their implementations with the implementations of other providers. A certain degree of interoperability is therefore tested - but this does not necessarily mean that the products comply with the standards, as they should. It is possible for two providers to interpret the standard in the same way - but both incorrectly! These products could therefore interoperate, but would not comply with the standard.

Conformance testing is therefore needed, which is designed to test the product through a series of rigorous tests to ensure that the product meets the set standards. If the tests are passed, the product is certified and receives a corresponding label. The Avnu Alliance has now created a series of conformance and interoperability tests with a defined certification process in different markets. Avnu is using this cross-industry experience to evaluate the tests and set them up for baseline certification in the industrial market.

Which organizations could now take on which tasks?

Zuponcic: Several organizations are currently working together to create a uniform standard and an interoperable ecosystem. These include Avnu for the conformance tests, the Industrial Internet Consortium - IIC for short - and LNI 4.0 for generating the testbeds, as well as the IEC, IEEE and OPC Foundation for defining the standards themselves. Avnu and the OPC Foundation are also working together to offer conformance tests 'from a single source' for OPC UA TSN. And industry consortia such as Profinet International, ODVA, Ethernet Powerlink Standardization Group could take on their own testing functions to ensure interoperability and compliance.

Complete factory-wide new installations will make up the smaller share. The majority of TSN implementations will be in existing installations. Are there any plans to support such 'brownfield' installations in terms of interoperability?

Walter: The topic of brownfields was an important focus of Avnu's activities. This is because, assuming that the interoperability of the basic elements is guaranteed, ensuring the appropriate interfaces for brownfield devices and systems is still a very critical issue. This includes mechanisms for encapsulating the application protocols, PTP profile conversion and flexible configuration mechanisms. In the IIC testbed we already show some of these runtime elements such as protocol encapsulation and PTP profile conversion.

The interfaces relate to specific services that need to be converted from existing devices and installations to TSN-based services and protocols. In the future, these interfaces could take the form of a time gateway for time conversion, a remote management unit for converting existing configuration protocols to Restconf or Netconf, or a TSN conversion mechanism for converting asynchronous data traffic to synchronous data traffic. Avnu conformance tests will therefore include conversion functions that support the addition of brownfield devices.

Is there already a roadmap for the upcoming activities?

Zuponcic: We are working hard on this, but we cannot yet publish the roadmap for final compliance and certification.

Around 80% of nodes in industrial applications will consist of 2-port bridges! What special conditions does this entail for future TNS products?

Zuponcic: The answer to this consists of two parts. Firstly, Avnu has structured its conformance tests in such a way that they are modular. This means that tests for a bridge - and the configuration for a bridge - are valid and consistent regardless of whether that bridge is a standalone network switch or the usual integrated bridge in a 2-port end device. This ensures that the market does not have exceptional situations where their systems do not scale or interoperate.

Secondly, two-port bridge devices often have other limitations in terms of performance and price - this is not only the case with 2-port devices, there is also a need for low-current and low-cost switches as well as switches with more ports. This requires a flexible and scalable approach to the configuration and use of these devices. To this end, Avnu Group supports flexible system management, for example remote management devices that minimize the requirements for devices to support TSN. In particular, a remote management device could allow an industrial device to receive configuration information via its own industrial protocol while still participating in the broader TSN architecture. This feature creates inclusivity for restricted devices with embedded bridges without compromising the benefits of TSN for the end user.

What can and will Avnu do to support the specific conditions of the industrial market?

Walter: Avnu will continue to advance conformance test specifications and methodologies that minimize conditions or special cases.