Why Industrial Ethernet Protocols Will Remain Relevant

July 28, 2022
While Time-Sensitive Networking technology can deterministically move data from one place to another via Ethernet, it’s the industrial Ethernet protocols that address specific application requirements.

Industrial facilities over the past two decades have seen a significant level of fieldbus communication networks replaced by industrial Ethernet. According to a 2021 study by HMS Networks, industrial Ethernet accounts for 65% of new installed nodes, while fieldbuses account for 28% of new installed nodes.

With the continued advance of Time-Sensitive Networking (TSN) through numerous new product offerings and its ability to bring determinism to standard Ethernet, some might wonder if it’s only a matter of time before the industrial Ethernet protocols like Profinet, CC-Link IE, EtherNet/IP, and EtherCAT begin to recede in the face of TSN. A closer look at TSN and the industrial Ethernet protocols explains why this is unlikely—and not possible in the foreseeable future.

According to Thomas Burke, global strategic advisor at CLPA (the CC-Link Partner Association), TSN technology only addresses network functions at Layer 2 (Data Link) of the Open System Interconnection (OSI) model for communications. Therefore, it’s only responsible for getting data from one place to another in a deterministic manner without looking at what the data is. What needs to be done with the data is typically handled at the higher-level layers that address application requirements. These are managed by industrial Ethernet technologies.”

Burke notes that some users may wonder why both TSN and industrial Ethernet are needed since most industrial Ethernet protocols can provide determinism when required. He says the answer lies in convergence.

“Typically, most of industrial Ethernet protocols do not allow different kinds of traffic to be merged on the same network,” says Burke. “TSN adds this missing capability by allowing multiple traffic types to share the same network while being handled in a deterministic way.”

Burke advises OEMs and end users exploring the use of TSN-enabled industrial Ethernet protocols to ensure those protocols can address the I/O, motion control, and safety aspects of the intended application. For example, he notes that CC-Link IE TSN's protocol uses layers 3 to 7 of the OSI reference model to build on the layer 2 TSN capabilities. “By doing this, it allows I/O, motion, and safety control to be integrated with standard TCP/IP traffic in a deterministic way.”