What are Industrial Network Edge Devices?

By Chantal Polsonetti

Industry Trends

The industrial network “edge” infrastructure tier is populated by devices such as Ethernet, wireless, and cellular gateways; Ethernet switches and routers; and wireless access points (WAPs). Network edge infrastructure devices play an increasingly important role as middleware entities that connect the field to the enterprise. These products have traditionally been relied on to bridge IT and OT environments, bring automation devices onto the enterprise backhaul, and/or bring legacy equipment into automation or enterprise architectures. An industrial gateway, for example, may be used to interface automation-specific machine networks to Ethernet backhauls, while a cellular gateway may link remote oil and gas installations to corporate operations. Today’s network edge products may also target sensor-to-cloud integration and/or edge computing to further industrial internet-based strategies and improve business performance.Industrial Edge Devices

Industrial network edge infrastructure devices are typically distinguished from commercial ones by not only their application but also their industrial packaging. This includes features such as extended environmental, shock, vibration, and surge ratings as well as DIN rail, 19-inch rack, or wall mount form factors.

Industrial Internet of Things (IIoT) Definition

ARC Advisory Group defines the industrial Internet of Things (IIoT) as connecting intelligent physical entities, such as sensors, devices, machines, assets, and products to each other, to internet services, and to applications. The IIoT architecture builds upon current and emerging technologies such as mobile and intelligent devices, wired and wireless networks, cloud com-puting, Big Data, analytics, and visualization tools.

The term IIoT is one of several terms associated with leveraging connectivity of industrial devices to achieve business benefit. Other examples include In-dustrie 4.0, popular in Germany, Europe, and China, as well as IT-OT convergence, smart manufacturing, and others. While the term “IIoT” is used throughout this report, it is understood to encompass these related terms as well due to the primary emphasis on connectivity.

Definition of a Connected Device

The industrial automation landscape is populated with numerous connectiv-ity options. Devices are deemed potential candidates for use in the IIoT by virtue of the type of network interface they support. Due to the focus on potential internet connectivity, only devices with Ethernet, industrial Ether-net, or Wi-Fi network capability are included. Devices used exclusively with serial, analog, or other non-internet-capable dedicated automation interfaces are excluded.

Industrial Network Edge Classification by Device Type

Presentation of the market data is largely from the perspective of the type of industrial network infrastructure device. The following sections detail the definitions of each respective network infrastructure device type.

Industrial Ethernet Switches

An industrial Ethernet switch is used to transmit Ethernet data frames be-tween devices connected to an industrial Ethernet network. Most Ethernet switches use the store-and-forward method to transmit frames between the Ethernet ports on connected devices. Industrial Ethernet switches are avail-able in managed, lightly managed, and unmanaged versions.

Numerous features further distinguish industrial Ethernet switches from their commercial brethren. These include ruggedized enclosures and high IP (Ingress Protection) ratings, DIN rail or rack mounting, industrial connect-ors, ability to withstand extended temperature ranges, passive cooling, redundant components, and conformance to industrial infrastructure stand-ards. Leading suppliers include Belden (Hirschmann), Siemens, and Cisco.

Industrial Fixed Ethernet Routers

The main purpose of a router is to connect multiple networks and forward packets destined for either its own or other networks. A router is considered a Layer 3 device because its primary forwarding decision is based on the in-formation in the Layer 3 IP packet, specifically the destination IP address. Industrial Ethernet routers provide IP routing between Ethernet-based in-dustrial and enterprise networks. These are largely the traditional type of industrial Ethernet routers that are used to establish VPNs and secure fire-walls to ensure secure communication between networks. Leading suppliers include HMS Networks, Siemens, and Belden.

Industrial Fixed Ethernet Gateways

An industrial Ethernet gateway is used to interface between Ethernet and networks that support different protocols. A gateway may contain function-ality such as protocol converters, impedance matching devices, rate converters, fault isolators, or signal translators as necessary to provide sys-tem interoperability.

Industrial gateways covered in this report are used to bring networked de-vices, whether IP based or not, onto IP-based networks and potentially into

the industrial internet. Due to the emphasis on industrial internet applica-tions, all master or backhaul networks must be IP based, which excludes serial and other non-IP masters. Leading industrial ethernet gateway sup-pliers include Advantech and Moxa.

Industrial Fixed Cellular Routers

Cellular routers leverage the 2G, 3G, 4G LTE, and, in the future, 5G cellular networks supported by telecommunication carriers. Cellular routers are used to enable remote monitoring and access applications in areas ranging from tank and pipeline monitoring to electrical substation automation and digital oilfield. Cellular networks are also used for remote industrial ma-chinery monitoring, allowing remote machine access without the need to pass data through a corporate LAN.

Industrial Fixed Cellular Gateways

Industrial cellular gateways primarily interface remote devices connected to 2G, 3G, or 4G LTE cellular to industrial Ethernet or wireless networks. Many of the new IIoT gateways support cellular interfaces, typically as a card-based slave interface to an Ethernet backbone. Cellular gateways have es-tablished their value proposition in areas such as preventative maintenance, remote programming, and usage monitoring in industries such as energy and oil & gas.

Industrial Wireless Routers & Access Points

Industrial wireless routers typically combine the functions of a wireless router as well as a wireless access point (WAP). These devices may function in a wired LAN, in a wireless-only WLAN, or in a mixed wired/wireless network, depending on the manufacturer and model. Leading suppliers in this category include Cisco, HP, and Zebra.

Industrial Wireless Gateways

This segmentation includes gateways that interface wireless slaves to a Wi-Fi master. This can include a variety of specific slave wireless protocols. Note that wireless to Ethernet (backhaul) gateways are included in the Ether-net category. General Electric and Honeywell are leading suppliers of industrial wireless gateways.

Industrial PC-based Gateways

Industrial PCs are ruggedized and built to meet specific industry standards. Typically, this means that they can be run round-the-clock and handle harsh industrial environments. Thanks to their computing power, memory capac-ity, and flexibility; IPCs can also be used as gateways and process additional tasks.

IPCs offer the potential to perform real-time analytics in the field and select data locally, avoiding the cost of having to send large volumes of often un-needed data over a network for storage in remote locations. The IPC can also simply buffer data, providing temporary storage and sending it to the next level as required. Leading suppliers of IPC-based communication gateways include Advantech and Siemens.

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