You may have noticed that I sometimes mention that routers and other devices has a watchdog. A watchdog is one of the things that makes 4G and 5G routers for professionals better than the ones you buy off the shelf from your local electronics store, for example. But what exactly is a watchdog, and why is it important? Let’s explain how a watchdog works and why it makes a big difference in business-critical installations.
Why a watchdog keeps your 4G/5G router running when it matters most
One reason a professional or industrial router offers a more stable connection is the many internal processes designed to keep the router running and the mobile network connection active. The routers and modems we provide for mobile connectivity have several built-in features that keep the connection alive.
Why is continuous connectivity so important? If you already work with mission-critical applications, you likely don’t need that question answered. But for everyone else: imagine an unmanned store or a rural fuel station. If the router loses connection and no watchdog is present, the system goes down. With a watchdog, the router reboots itself and is usually back online within minutes. No unnecessary travel. No downtime. No lost revenue.
What a watchdog does
A watchdog monitors whether all internal routines in the hardware are functioning. It can monitor whether software is being executed correctly—this is called a software watchdog. It can also ensure all components in the router are operating as they should—often referred to as a hardware watchdog.
Hardware watchdog – the internal safety valve
A hardware watchdog can be implemented in different ways depending on the router’s design, but it’s generally an extra circuit on the router’s mainboard that monitors the processor, modem, and other components. Often, though not always, there is a separate chip that checks the router’s activity every second. If a fault is detected—if the processor or modem, for example, stops responding—the watchdog can cut power and restart the entire router. This function is active automatically during operation and doesn’t require manual activation. The only time it is disabled is during startup, when the system waits until the processor is running and the router is functioning as expected.
Software watchdog – automatic restarts
The router’s built-in firmware contains several processes that ensure the software is continuously running. For example, a software watchdog runs background code that checks whether the software is executing correctly. If the software crashes or freezes, the watchdog triggers a restart. A software watchdog doesn’t need a hardware counterpart to reboot the system, but when both are present, they work together. If either one detects a fault, the router—or specific processes—are restarted. One example: the firmware includes a service that checks whether the router is registered in the mobile network. The watchdog monitors this, and if it is not registered, it resets the 4G modem. If this fails after a set number of attempts, the router reboots entirely. Many routers now offer a configurable threshold for how many failed attempts should trigger a full reboot—adjustable in the firmware.
Ping-reboot keeps the connection alive
The firmware includes a feature called Ping Reboot, which periodically sends ICMP requests (commonly called ping) to a defined IP address or host to verify internet or service reachability. If no response is received after a pre-set number of attempts, the router reboots. You can often configure the interval, i.e., how frequently the router checks internet connectivity.
Automatic reboot
The router can also be set to restart automatically at specific times. This helps prevent potential connectivity or operational issues. Restarting clears cache memory and temporary data stored for quick access, which over time may slow down processes. Think of it like rebooting a computer—a good practice for optimal performance.
SMS alerts on failure
If the router loses its data connection, it can send an SMS alert. Most routers also support reboot via SMS. If the router fails to reconnect and doesn’t restart automatically, you can send an SMS command to force a reboot.
Cloud services on alert
Remote management tools for routers and hardware are almost a requirement in many installations today. They save travel time and reduce downtime. These tools not only notify you when a device becomes unreachable, but also provide historical performance data—useful for identifying problems like an incorrectly sized antenna or unstable power supply. These services often cost just a few euros per month and offer a very low-cost way to ensure high operational reliability.
Switch SIM card on poor signal
Many routers in our lineup have dual SIM slots, allowing the router to switch SIM cards if the primary signal or network quality drops below a critical level. This means that if you want a backup operator, the router switches over to the secondary SIM and returns to the primary when conditions improve. This ensures stable connectivity even during network issues.
An alternative to dual SIM, which is often even easier to manage, is using roaming SIM cards. Just like when your phone switches carriers abroad, these SIMs automatically change between all available networks in your country—e.g., between all major operators in Sweden. It’s a secure solution managed by the network and operator, and it works even if your router only has a single SIM slot.
Choose a router that delivers
If your connectivity is critical, invest in a device with a watchdog function, that is one important feature that ensures connectivity —whether you’re in construction, energy, industry, or transport.