A router board makes a good IoT gateway when you want OpenWrt, several network segments (IoT VLAN, guest, LAN), a VPN, or a cellular uplink, and don't need a desktop, camera or big GPIO header.
| OpenWrt One | BPI-R3 Mini | BPI-R3 | BPI-R4 | |
|---|---|---|---|---|
| SoC | MT7981B (Filogic 820) | MT7986A (Filogic 830) | MT7986 (Filogic 830) | MT7988A (Filogic 880) |
| RAM | 1 GB | 2 GB | 2 GB | 4 or 8 GB |
| Flash | 256 MiB NAND + 16 MiB NOR (recovery) | 128 MB NAND, 8 GB eMMC | 128 MB NAND, 8 GB eMMC, microSD | 128 MB NAND, 8 GB eMMC, microSD |
| Wired | 1x 2.5G WAN, 1x 1G LAN | 2x 2.5GbE | 5x 1GbE, 2x 2.5G SFP | 4x 1GbE, 2x 10G SFP |
| Wi-Fi | Wi-Fi 6 onboard | Wi-Fi 6 onboard | Wi-Fi 6 onboard | via Wi-Fi 7 miniPCIe cards |
| Cellular | — | M.2 Key B (5G modules listed by Banana Pi) | mini PCIe (USB) for LTE | M.2 Key B for 4G/5G |
| Power | USB-C, PoE on WAN | 12 V (20 W) or USB-C PD | 12 V / 2 A | 12 V / 5.2 A or 19 V / 3.2 A |
All values come from Banana Pi's and OpenWrt's pages for each board; see the dedicated R3 and R4 items for their boot switches and pitfalls.
Which one
- OpenWrt One: the OpenWrt community's own development board. Its 16 MiB NOR holds a protected backup system, and a NAND/NOR DIP switch lets you boot the recovery system, so a failed flash doesn't brick it. PoE on the WAN port means a single cable can power it. The best pick when you mainly want a robust, well-supported OpenWrt box.
- BPI-R3 Mini: small (65 x 65 mm), two 2.5GbE ports and an M.2 slot for a 5G modem (Banana Pi lists Quectel RM500U-CN and RM520N-GL). Good for a cellular-backed gateway. Its specification lists NAND and eMMC as storage, with no microSD slot.
- BPI-R3: many ports and SFP for a home or lab network with separate segments. Mind the 2.5GBase-X-only SFP ports.
- BPI-R4: 10G SFP and Wi-Fi 7, but Wi-Fi costs extra and the Wi-Fi card needs the 19 V supply.
For an IoT gateway in practice
- Put IoT devices in their own network segment and allow only what they need (MQTT broker, NTP, update servers).
- Run the broker or Home Assistant on a separate machine or container host if the router has little RAM; 1 GB (OpenWrt One) is plenty for routing, not for a full smart-home stack.
- Prefer boards whose model has an official OpenWrt device page and current releases.