What is an IoT gateway?
In an IoT architecture, sensors, meters, and controllers generate data using “field” protocols designed for industrial use, not for the Internet. Sending all of this data directly to the cloud would be nonsensical from an economic, energy, and strategic standpoint. The IoT gateway aggregates, sorts, and translates these data streams before transmitting them.
Specifically, an IoT gateway serves three purposes:
- Multi-protocol data collection — it queries devices via Modbus, RS-485, BACnet, M-Bus, LoRaWAN, or Zigbee.
- Translation & Preprocessing — it converts raw data into structured messages (MQTT/JSON), filters, aggregates, and time-stamps the data at the edge (edge computing).
- Secure transport — it pushes data to the cloud via an encrypted tunnel, most often over a cellular network.
It serves as the bridge between devices and the cloud: without it, it would be impossible to monitor a heterogeneous fleet from a single interface.
IoT Gateway vs. Router: Don’t Confuse the Two
The two are often confused because a modern IoT gateway includes a router. However, the distinction is clear.
| Criterion | Traditional Router | IoT Gateway |
|---|---|---|
| Main Function | Forward IP packets | Collect + translate + route |
| Field Protocols | None | Modbus, RS-485, BACnet, M-Bus… |
| Data Processing | No | Filtering / aggregation at the edge |
| Cloud connection | Raw | Structured MQTT / HTTPS |
| Industrial VPN | Optional | Built-in by default |
| Remote locations (4G/5G) | Depending on model | Yes (embedded SIM) |
For more information on this topic, see our comparison of industrial routers vs. internet boxes and the IoT Router page.
How an IoT Gateway Works: The Architecture
The gateway is positioned between the OT network and the cloud. It does not expose any incoming ports: the connection always goes from the gateway to the platform, which drastically reduces the attack surface. Data is cached locally if the connection is lost, and then resynchronized.
Why Edge Preprocessing Changes Everything
Sending each raw measurement to the cloud every second uses up a lot of mobile data and obscures useful information. A good IoT gateway applies rules at the source:
- Send only in the event of a threshold exceedance or a significant variation;
- Aggregate (average, min/max over 5 minutes) before transmission;
- Detect anomalies locally and trigger an immediate alert without waiting for the cloud;
- Buffer data during a network outage.
This edge filtering reduces connectivity costs and improves the reliability of monitoring. It is a cornerstone of IIoT predictive maintenance.
Criteria for Choosing an Industrial IoT Gateway
- Supported Protocols — Check for Modbus RTU and TCP, RS-485, and the bus systems used in your facility (BACnet, M-Bus, etc.).
- Connectivity — 4G/LTE or even 5G, with multi-carrier SIMs for resilience.
- Security — Outbound VPN, signed firmware, OTA updates, IT/OT segmentation.
- Provisioning — zero-touch provisioning (ZTP) for mass deployment without an on-site technician.
- Form Factor & Ruggedness — DIN-rail mounting, industrial temperature range, wide input voltage range.
- Fleet Monitoring — a cloud console to manage all gateways; otherwise, operations become unmanageable.
The Eziwan Approach
The Eziwan Gateway is an all-in-one industrial IoT gateway: Modbus/RS-485 data collection, 4G/LTE router with multi-carrier SIM, built-in VPN client, and zero-touch provisioning. When paired with the Eziwan Cloud, it provides centralized monitoring of your entire fleet, alerts, and secure remote access—all from a single interface.
Whether you’re equipping pumping stations, solar power systems, or a fleet of remote-reading meters, the same gateway and platform can be adapted to your specific use case.