Industrial Ethernet is an important communication technology used in industrial applications. Real-time Ethernet is one of the most established wired communication technologies for cyber-physical control applications. Examples of use cases where it is applied include:

• Motion control
• Control-to-control communication
• Control-to-sensor/actuator communications
• Mobile robots
• Remote access and maintenance
• Closed-loop process control
• Process monitoring
• Plant asset management

Compared to standard IT communication, these technologies have specific requirements, such as:

• Short communication cycle times and concurrent communication cycles with divergent times
• Typically, a large number of short Ethernet frames
• Highly precise synchronization for certain applications
• Transmission of functional safety protocols (see IEC 61784-3)

Industrial Ethernet network communication can be established on different layers, each requiring different 5G network capabilities:

1. IP connections (layer 3): Communication established on or above the IP layer. Nothing special is required from the 5G system, as long as the automation device includes a 5G module. If a router is placed between the device and the 5G system, then the network and devices must be configured, via NAT or specific 5G mechanisms, to enable communication. (e.g., EtherCAT Automation Protocol, Ethernet/IP)
2. Bridged networks (layer 2): Communication is established directly at the MAC address layer. This requires the UE, 5G RAN, and 5G core to support Ethernet PDU or have the capability to encapsulate Ethernet frames into IP packets, i.e., through tunneling. (e.g., EtherCAT Automation Protocol, POWERLINK, PROFINET)
3. Non-bridged networks: Communication does not rely on address information in the Ethernet frame but rather on data in the payload. Due to the ring topology, which may not always map directly to the 5G system, this could require proprietary, non-standardized solutions. (e.g., EtherCAT, SERCOS III, PROFINET IRT)

As mentioned above, bridged networks require the 5G system to support either Ethernet PDU or encapsulation of Ethernet frames into IP packets (tunneling). For the end user, this means that one of these options must be supported both by the UEs used in the industrial Ethernet use cases and by the 5G system itself. Both the UEs and the 5G system must be configured to utilize Ethernet PDU. For tunneling, only the UEs involved in the tunnel need to be configured, unless the connection to the data network is also part of the tunnel, in which case the 5G system must be configured accordingly. Some tunneling protocol options include VXLAN and GRETAP.

One drawback of tunneling is that it compromises real-time capabilities. Tunneling protocols such as VXLAN can encapsulate the VLAN TCI and restore it when the packet exits the tunnel, but within the core network, the requested IEEE 802.1Q priority is not preserved. Currently, tunneling is more commonly supported in commercial products than Ethernet PDU, although Ethernet PDU support is expected to grow in the medium term.

Synchronization of industrial Ethernet networks is also critical in specific use cases. Precise synchronization is the foundation for enabling TSN over 5G, which would make applications like motion control and similar use cases possible. UEs can synchronize their working clocks using the 5G radio connection to transmit time synchronization information, but this method lacks the precision required for all industrial use cases due to asymmetric uplink and downlink and transmission time jitter. According to specifications, UEs can also be synchronized using a native 3GPP-defined mechanism that provides greater time accuracy; however, this is not yet commercially available.

For more information about industrial Ethernet networks, deployment options combining industrial Ethernet and 5G networks, and time synchronization in these systems, please refer to the white paper “Integration of Industrial Ethernet Networks with 5G Networks.”

Time synchronization over 5G is also explained in more detail in the white paper “Integration of 5G with Time-Sensitive Networking for Industrial Communications.”