The Role of the 4G-to-Ethernet Gateway in Industrial Architecture
In most industrial facilities, field devices (PLCs, HMIs, meters, IP sensors) are already connected via an Ethernet local area network. The problem is that this LAN often lacks a reliable WAN connection—either because the site is isolated, because fiber is not available, or because the existing connection is insufficient or unreliable.
Eziwan’s industrial Ethernet 4G router solves this problem by adding a 4G WAN gateway to the existing LAN without having to restructure it:
- Existing equipment retains its IP addresses and network configuration
- The 4G router connects to the existing switch (or directly to the PLC)
- It automatically establishes an encrypted VPN tunnel to the cloud or your data center
- All WAN traffic passes through the 4G connection—monitoring, remote access, and configuration downloads
No PLC reconfiguration, no IP address changes, and no production downtime during installation.
Managed Ethernet Ports: Flexible OT Network Architecture
The Eziwan 4G router includes a managed Ethernet switch with full VLAN support, allowing you to build sophisticated OT network architectures within the same cabinet:
| Port | Possible Configuration | Typical Use |
|---|---|---|
| ETH1 | LAN, Secondary WAN | Main PLC, backup fiber |
| ETH2 | LAN, DMZ | OT network switch, local HMI |
| ETH3 | LAN, DMZ | IP camera, Ethernet sensor |
| ETH4 | LAN, Secondary WAN | Supervisory PC, IT access |
VLAN trunk mode allows multiple VLANs to be carried over a single Ethernet cable to a third-party switch (Hirschmann, Moxa, Cisco IE) for more complex network topologies.
VLANs and OT/IT Segmentation: IEC 62443 Compliance
The IEC 62443 standard (cybersecurity of industrial control systems) recommends segmenting OT and IT networks to limit the spread of security incidents. The Eziwan 4G router allows you to implement this segmentation without an additional switch:
VLAN OT (control network): PLCs, HMIs, Ethernet sensors. Restrictive firewall policies: Only SCADA/Modbus TCP traffic to the Eziwan cloud is allowed outbound. No direct access from the IT network.
IT VLAN (supervision network): Supervision PC, VPN clients, remote access. Access to OT VLANs is permitted only through explicit firewall rules (port 102 for S7, port 502 for Modbus TCP).
VLAN Management: the router’s own administration interface, accessible only from the VPN or a dedicated management network.
Supported Protocols: From Modbus to MQTT
The Eziwan 4G Ethernet router does more than just provide transparent IP transport. It includes an industrial protocol gateway:
- Modbus TCP: Direct remote access to PLC registers via VPN
- Modbus RTU → Modbus TCP: Conversion from the RS-485 port to the Ethernet LAN
- Modbus RTU → MQTT: Collection of Modbus data and publication to your MQTT broker (AWS IoT, Azure IoT Hub, Mosquitto)
- SNMP: Monitoring of the network status of connected devices using IT monitoring tools
This application layer enables OT devices without native IP connectivity (RS-485 meters, legacy Modbus RTU controllers) to be connected to the industrial cloud via the control cabinet’s Ethernet network.
4G Latency and Suitability for SCADA Applications
The latency of a 4G LTE connection is 20 to 50 ms under normal conditions on French networks. Compare this value to the requirements of your applications:
| Application | Required Latency | 4G Compatible? |
|---|---|---|
| SCADA Monitoring (cycle >1s) | < 500 ms | ✓ Yes |
| Remote HMI Access | < 200 ms | ✓ Yes |
| IoT Telemetry (10s+ cycle) | < 1000 ms | ✓ Yes |
| File and Log Transfer | Non-critical | ✓ Yes |
| PID control loop | < 10 ms | ✗ No (prefer local fiber) |
| Motion control (CNC) | < 1 ms | ✗ No |
For real-time control applications, 4G is not a substitute for a local network. However, it is perfectly suited for all monitoring, maintenance, and remote access applications.
Installation and Commissioning: No Reconfiguration of the Existing LAN Required
Deploying the Eziwan 4G Ethernet router in an existing industrial network follows a simple procedure that does not disrupt production:
- Connect the router to the existing switch via an available Ethernet port (standard RJ45 cable)
- Insert the M2M SIM cards into the router’s nano-SIM slots
- Connect the 24V DC power supply from the cabinet’s power source
- Wait for automatic provisioning (2–3 minutes): the router downloads its configuration from the Eziwan cloud and establishes the VPN tunnel
Once the service is up and running, your existing LAN devices will connect to the Internet via 4G and can be accessed remotely through the Eziwan VPN—without any changes to their network configuration.