Operational technology (OT) is undergoing a very similar transformation to the one that information technology (IT) undertook in the 1980s and ‘90s. OT networks for controlling manufacturing processes or providing occupant comfort and safety in buildings are moving away from complex amalgamations of legacy, built-for-purpose protocols to seamless, Ethernet-based frameworks.
But there's understandable risk aversion among the operators of these networks. If the elevators in an office building stop working…if the lights stop behaving as anticipated…if it's suddenly too warm in the facility…if there are supposed to be 10,000 widgets on the pallet at the end of a shift and there are only 8,800…suddenly, somebody is hunting the OT network operator’s head. The mindset of the OT world historically has been, above all, to deliver the function safely and reliably and make sure things (almost) always work. In that light, continuing to rely on the network tools that have been working for 25 or more years remains a very appealing approach in OT.
Cybersecurity issues related to those legacy, built-for-purpose protocols that dominated OT networks have grown more and more glaring in recent years. OT networks traditionally relied on “security through obscurity”—rogue actors not long ago largely neither saw nor understood OT, and so they left it alone. Today, however, they have recognized an opportunity to, for example, access a thermostat and move up the network to compromise more valuable corporate assets.
Change has been accelerating over the last decade. Applications are moving from older fieldbus-style networks to Ethernet, which is now widely regarded as a key enabling technology for the Fourth Industrial Revolution, or “Industry 4.0.”
Single-Pair Ethernet (SPE) is the bridge from where the OT world is today to where it must go tomorrow if it is to successfully address the tremendous array of challenges that building and industrial automation operators face moving forward.
Picture an OT network as a stack of boxes. The top box is the cloud, and the bottom box is where all the sensors and actuators are—the edge of the network. OT networks once were siloed from Ethernet-based IT networks, but Ethernet has been steadily creeping down the OT stack. The technology has now reached the top of the programmable logic controllers (PLCs). Defined in IEEE 802.3cg, SPE provides a way to upgrade this edge of OT networks.
SPE is a breakthrough that enables OT networks to become part of a seamless Ethernet-based network. The same topologies that the OT world has relied upon historically are still supported but with substantial boosts to performance, security, flexibility, and manageability. OT applications and data are more transportable throughout the network, without requirements for translation gateways or need for distinct networks with different technologies to be merged or separated. Plus, because Ethernet is well known, the ability for developers and operators to easily find knowledgeable talent is enhanced, further accelerating adoption. The transition to Ethernet is a key part of enabling OT network operators to make use of the network control tools that IT has developed over the last 30-plus years.
Also, with SPE, the media is very similar to what's already deployed for the legacy serial networks—two wires of cables with characteristic impedance of about 100 Ω. Importantly, this means that deployed cables potentially can be reused, which substantially lowers the barriers to entry. This characteristic sets up the possibility of either migrating to Ethernet without restructuring a plant or designing a new plant and having a familiar fallback if problems are encountered.
Paving the way forward
SPE, furthermore, avails the OT world with a range of innovations and lessons learned that the Ethernet ecosystem has grown, developed, and hardened in IT networking over the last 40 years:
- Providing power and data on the same wires – Using Power over Ethernet (PoE), Ethernet has transformed networks from just providing control to also powering devices. The latest PoE standard from IEEE defines up to 71.3 W of power at the device end. In SPE, a single-pair variation of PoE (SPoE, sometimes called PoDL) can deliver up to 52 W. PoE and SPoE deliver the greater levels of robustness and efficiency to the technique for passing electrical power along with data on Ethernet cabling to compel automation, building, and industrial network operators toward PoE.
- Time-Sensitive Networking – A question that perplexed the OT world in the early days of Industry 4.0 and the Internet of Things (IoT) was how to ensure that applications would be transported and delivered in the proper time sequence. Ethernet’s Time-Sensitive Networking (TSN) capability, first developed and standardized for audio and video stream distribution, has gradually been extended for tighter and tighter timing constraints in applications such as industrial control and automobiles.
- Network Segmentation – The ability to do even simplistic things that Ethernet affords at the edge of the network—segmentation, virtual local area networks (VLANs), etc.— goes a long way in beefing up OT networks for the cybersecurity challenges that they have encountered in recent years.
Building- and industrial-automation networks are indicative of Ethernet’s growth into more and more varied deployment scenarios. The Ethernet Alliance’s Ethernet Roadmap is the industry’s only publicly available Ethernet guide sharing key underlying technologies, and current and future interfaces across the diversifying application horizon.
Already, future iterations of the roadmap are being planned, and operators of building- and industrial-automation networks are to engage with the Ethernet Alliance, the voice of Ethernet, to participate in tracking the technology’s ongoing evolution.
Peter Jones is the chair of the Ethernet Alliance. He is a Distinguished Engineer in the Cisco Networking HW team. He is active in IEEE 802.3. He works on the evolution of technology to add value to physical infrastructure and make technology consumable.
Razvan Petre represents Spirent as a Principal Member of the Ethernet Alliance. He is a product manager for Spirent Communications’ TSN portfolio. He helps design test and assurance solutions addressing next-generation TSN device and network testing needs for a wide range of verticals including automotive, industrial automation, aerospace, and service provider networks.
Bob Voss is the SPE subcommittee chair for the Ethernet Alliance. He is a Distinguished Engineer, Panduit Corporate Research and Development, located at the Jack E. Caveney Innovation Center. His practice areas are Industrial Automation, Building Automation and the Internet of Things.