Възможно ли е моят интернет маршрутизатор да се изнася?

I’ve been having problems with my internet connection over the past weeks (intermittent disconnections, slow transfers, etc.), and my provider keeps telling me that the problem is not on their end.

I have cable modem with a Wi-Fi router (this router was not provided by them).

The router is quite old (DIR-300), so I’m starting to wonder if it could be the issue and if I should replace it.

Is it possible that it is the cause? Can they become so outdated that they cause intermittent interruptions of service?

If I reset the modem and the router, they work fine for a few hours, but the problems starts again after a while.

Yes.

In general, routers can and do fail. The primary cause of failure for consumer grade equipment is heat stress. Most consumer grade hardware runs far too hot and have respectively poor air circulation compared to their ventilation needs.

Long-term exposure to heat causes various components to degrade/fail and manifests itself as “intermittent” problems. In general, consumer grade hardware is not as robustly made as commercial or enterprise hardware. But all physical devices are subject to physical effects.

It’s not uncommon for consumer grade devices to fail within a few years due to heat or vibration issues. Routers stuck near windows (argh! the sun!), placed on the floor (dust!), or jammed into a bookcase (no air flow) are especially prone to failures. Contrast that with commercial grade devices which are often still working for 10 or more years after their first deployment.

Most cable modems have either an Ethernet port or Wi-Fi ability. To isolate the cause of your network problems, you should consider bypassing your router and plugging your PC/laptop directly into the cable modem to see if whether or not you experience the same problems.

Of course, bypassing the router means you bypass the router’s firewall protection and NAT abilities so take due precautions on your computer.

A (possibly) good example of the Second Law of Thermodynamics:

«Any transformation of a thermodynamic system is carried out with increase in entropy including overall entropy of the system and the external environment.»

You wrote:

If I reset the modem and the router, they work fine for a few hours, but the problems start again after a while.

This may be an overheating problem or the overheating is the symptom…

The easiest way to check if the router is Out of Service or near to this inevitable state, you may try with another one temporary (from a friend for example). If this solved the Internet connection problems, you have the answer.