KNOT IoT Gateway (RB924i-2nD-BT5&BG77)

The KNOT (product code RB924i-2nD-BT5&BG77) is a small gateway for field equipment. The catalogue lists it as an LTE device with the default configuration router-lte and lte1 as the WAN interface. The shape matches: two small ethernet ports, one radio on 2.4 GHz and a modem, in a box that belongs on a pole or in a cabinet.

Two catalogue figures decide what fits here: the ports are 100 Mbit and there is 64 MB of memory. That last number is exactly the line at which the configurator raises its small-board warning.

The ports and the modem

• lte1: the modem, and your WAN by default. This is where your carrier's APN goes.
• ether1: 100 Mbit, with PoE-in. Your power cable, if you feed it that way.
• ether2: 100 Mbit, without PoE.

There is no PoE-out: the catalogue records no feeding port on this model, so the PoE-out per port field never appears. A sensor or camera behind it needs its own supply. See PoE-out per port.

Two wired ports is fewer than the three some roles demand. Office router with VLANs, Router + CAPsMAN and Hotspot are therefore greyed out with "Needs at least 3 wired ports (WAN + LAN + trunk)". What ends up in the bridge is covered in Bridge and ports.

The product code mentions Bluetooth 5, but our catalogue does not record that field. The configurator therefore knows nothing about it and writes no lines for it; whatever you want from the Bluetooth side, you arrange on the device itself.

The radio

One radio, wlan1, on 2.4 GHz. No 5 GHz. For a handful of sensors and a laptop on site that is enough; for a room full of clients it is not. The Wi-Fi package is wireless, the older of the two in RouterOS v7, so the script writes /interface wireless. No WPA3, no 802.11r, no configurable management frame protection. The catalogue records no Wi-Fi generation for this model. See Setting up Wi-Fi and Channels, width and power.

With a single radio the repeater role uses a virtual AP on that same radio to broadcast. The tool ticks that box for you; remove it and the repeater broadcasts nothing.

What is inside

From the catalogue: MIPSBE, 64 MB of memory, licence level 4 and the QCA9531 switch chip. At 64 MB the small-board warning appears: RouterOS v7 runs, but there is not much room. Keep the configuration small, do not install extra packages, and check what is left with /system resource print after pasting.

Licence level 4 is enough for what this device does, but it is not unlimited; see RouterOS licences. hw_vlan is empty, so you do not get the warning about bridge VLAN filtering and hardware offload here. That does not make VLANs free on this board: with two ports and 64 MB a VLAN setup is rarely worth it.

What it is good at, and where it runs out

Good at: putting a few devices in a remote spot on the internet through a SIM, with Wi-Fi alongside for whoever walks up with a laptop.

Where it runs out:

• 100 Mbit. On a fast mobile connection the cable is the bottleneck.
• 64 MB. No hotspot, no containers, no large firewall sets.
• Carrier-grade NAT. Mobile internet often sits behind CGNAT, so port forwarding and inbound VPN do not work. Build an outbound tunnel; see WireGuard.
• One 2.4 GHz radio. Range, not speed.

Which roles fit

• LTE / 5G router: the role this device exists for. It appears because the catalogue records a modem.
• Home router: if you would rather use ether1 as the WAN.
• Access point and CAP (managed by CAPsMAN): Wi-Fi behind another router, everything bridged.
• Wireless CPE / point-to-point and Wi-Fi repeater: available, with the single-radio caveat.
• VPN gateway: available. Mind CGNAT, and what encryption costs this board.
• Harden only (baseline): the safest choice on a board this small, because it leaves the network alone.

The quickest route to a working configuration

1. Pick One device and search for KNOT or RB924.
2. Pick the LTE / 5G router role.
3. Fill in the APN and leave the rest of the uplink alone.
4. Set up the LAN, see LAN and DHCP, and keep it small.
5. Set the country and one SSID, set an admin password, reset and paste. See Using the script.

Afterwards check /interface lte print and /ip address print. No address on lte1? See LTE does not connect.

What trips people up

• The wrong APN. Signal enough, no internet.
• Looking for Bluetooth in the tool. The catalogue does not record it, so the configurator does nothing with it.
• Copying a bigger router's configuration here. What fits on a hEX does not fit here.
• Letting memory fill up. If the device keeps rebooting or an upgrade fails, look at free memory first; see High CPU load.
• Assuming unlimited data. A camera behind a SIM drains a bundle quickly.