Earlier this year, the Industrial Internet Consortium (IIC), National Instruments, Bosch Rexroth, Cisco, Intel, Kuka, Schneider Electric and TTTech announced a collaboration to develop the world’s first time-sensitive networking (TSN) testbed to advance the network infrastructure that will support the future of the Industrial Internet of Things (IIoT) and Industry 4.0. Machine designers, builders and users need reliable and secure access to smart edge devices, and standard network technologies will evolve to meet the requirements of the next generation of industrial systems.
TSN is a set of IEEE 802 standards designed to enhance Ethernet networking to support latency-sensitive applications that require deterministic network performance.
The goal of the IIC testbed is to display the value of new Ethernet IEEE 802 standards, referred to as TSN, in an ecosystem of manufacturing applications (Figure 1). TSN powers a standard, open network infrastructure that supports multi-vendor interoperability and integration, as well as real-time control and synchronization between motion applications and robots, for example, over an Ethernet network.
At the same time, TSN is designed to support traditional traffic found in manufacturing applications; this can’t be accomplished without the convergence of IT and operational technologies.
“This testbed seeks to discover and invent new products and services leveraging the Internet of Things in industrial systems,” says Dr. Richard Soley, executive director of the IIC. “The testbed developers realize that their markets will be disrupted by IoT and are developing this testbed to discover and invent that disruption. This testbed will prove the value and functionality of IEEE 802 time-sensitive networks in machine-control applications.”
Testbeds are a major focus and activity of the IIC and its members. “Our testbeds are where the innovation and opportunities of the industrial Internet—new technologies, new applications, new products, new services and new processes—can be initiated, thought through and rigorously tested to ascertain their usefulness and viability before coming to market,” explains Soley.
The testbed will combine different critical control traffic, such as OPC UA, and best-effort traffic flows on a single, resilient network based on IEEE 802.1 TSN standards. It will demonstrate TSN’s real-time capability and vendor interoperability using standard, converged Ethernet, and it will assess the security value of TSN and provide feedback on the ability to secure initial TSN functions. Equally important is the testbed’s attempt to show the IIoT’s ability to incorporate high-performance and latency-sensitive applications.
In the past, real-time control applications typically were deployed using nonstandard network infrastructure or unconnected networks that left the devices and data siloed and difficult to access. TSN’s value is in unlocking data in real time and fulfilling the IIoT promise of improved productivity from big data analytics and smarter systems.
IEEE 802.1 is the specification for switch operation. “One aspect we’re focusing on in this testbed is scheduling,” explains Todd Walter, chief marketing manager, National Instruments (NI), and industrial segment chair, AVnu Alliance. “The profile of IEEE 1588 for precision time protocol (PTP) is to distribute time and synchronize all of the end nodes and all of the switches, so they all have common concepts of time, or synchronized time. Switches already have the ability to look at a packet and put it in different queues. TSN creates a reservation for a particular packet at a particular time. The bridge can identify the packet and gives it a fully scheduled pass through the network. For control applications, that’s ideal.”
The testbed is focused around smart manufacturing because TSN will have applicability across a lot of industries. IIC member companies bring their own devices to the testbed. “One application we’ll test will be machine-to-machine coordination between a robot and another machine,” explains Walter. “A robot has a controller, sensors, actuators, drives and motors. We’ll communicate through some standard interfaces and commands to coordinate the robot controller with another machine that has motion, sensor or vision integration; and we’ll be able to put those multiple controllers together with multiple systems being coordinated—for example, coordinating a Kuka robot with a Bosch Rexroth motion system. We’ve structured the testbed to be able to support many standard protocols.”
The testbed is physically hosted in Austin, Texas, at the National Instruments campus, where NI is handling the design. Cisco and TTTech are supplying the switching (Figure 2). The major components are scheduled to be integrated by the third quarter of 2016. “We plan to come out with feedback to the conformance bodies and then reference architectures and guidance by the fourth quarter,” explains Walter.
Security and safety
For TSN, security has to be designed-in as a layered system, explains IIC’s Soley. “One cannot add security as a new feature later,” he warns. “Air-gapping, while the obvious approach to perimeter security, has major drawbacks—most obviously the loss of the air-gap, that is, the accidental or intentional connection of a supposedly air-gapped system to the Internet. But, more pervasively, air-gap security ignores the fact that the vast majority of security failures are perpetrated by insiders. Air-gap security, as a perimeter measure, cannot guard against insider threats. The developers for this IIC testbed are aware of the issues and developing their time-sensitive networks with security in depth designed-in.”
The security level needs to be pushed as far down as possible, adds NI’s Walter. “When there’s a network infrastructure that’s open, that creates a security hole,” he cautions. “If you can get access to that layer, you can get everywhere. We want to push security all the way into the end node. In addition to being able to adopt all of the IT best practices for security, we can add another layer of security because we have information about the data flows. We know the timing and the path, and that can be another powerful tool for the layers of security. In the testbed, we want to figure out what we can apply that’s already in use and what we also can add.”