Wondering Aloud About Device Discovery

In the IT world, both network pings and System Network Maintenance Protocols (SNMP) provide a way for networked devices from different vendors to advertise identity, capabilities and other useful characteristic information. Wouldn’t it be nice if the OT world has something like that?

Network pings are messages sent to every possible address to determine who exists. New devices can be discovered by comparing the list of devices responding to the ping to the list of known devices. For detailed information on an enterprise device, enterprise network tools use the SNMP to interrogate devices to learn the device type, get real-time status updates on attributes like print toner, read configuration and monitor the operation of a device. SNMP is built into almost every IT device.

Imagine if the OT world had something vendor-neutral built into devices that allowed a supervisory system to identify the devices on a network, their configuration and what capabilities they have, information that is essential to the maintainability of a plant floor network. Wouldn’t it be nice?

Good things come to those who wait. The Link Layer Discovery Protocol (LLDP) is now being promoted by both the ODVA and Profinet International (PI) to address this lack of device discovery. PROFINET was the first factory floor technology to make LLDP a required component of every device. ODVA is planning to make it mandatory later in 2022, and support for LLDP will be required for all EtherNet/IP devices in 2022 or 2023. Vendors building EtherNet/IP devices would be smart to immediately begin incorporating LLDP into their devices.

A Brief Overview of LLDP

LLDP is a Layer 2 (of the OSI Model) protocol, detailed in IEEE 802.1AB-2005. It replaces several proprietary protocols implemented by individual vendors and supported only on their equipment. LLDP was introduced by the Internet Engineering Task Force (IETF) to standardize a vendor-neutral mechanism for exchanging device information.

The typical information that is gathered using LLDP includes several items particular to devices, like routers and switches, on enterprise networks.

  • System name and description
  • Port name and description
  • VLAN name and identifier
  • IP network management address
  • Capabilities of the device (for example, switch, router or server)
  • MAC address and physical layer information
  • Power information
  • Link aggregation information

There is also a portion of the LLDP messaging protocol that provides custom data fields so information about factory floor devices can be tailored even further.


The factory floor was in dire need of device discovery capabilities and LLDP solves that problem. It identifies devices, connections between devices and provides detailed configuration data, while also providing manufacturers with a single place to view device configuration data for a network. This is a significant step forward for automation specialists who design and implement these complex systems.

For a more in-depth look at LLDP, check out our LLDP tech page. If you need help determining what’s right for your particular application, Real Time Automation can help. We’ve been delivering innovative communications solutions to the industrial automation market since 1989. Our products seamlessly integrate your process equipment so you can collect, analyze and interpret the real-time data you need to improve productivity and maximize efficiencies.

RTA specializes in making easy-to-use connectivity products, including industrial protocol gateways, embedded source code stacks and customized OEM solutions. Our products are used by control engineers on factory floors all over the world and come backed by our industry-leading Enginerd® tech support to help you save time, money and aggravation. And, our products come with a 5-year warranty, are made in America and are always in stock, ready to ship the same day you place an order.

At RTA, we move your data…so you can move your business forward.

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