How to implement a modem reconnection in the router when the connection is lost?

Question

Computer networks

There is an Asus RT-AC68U router, a 3G / 4G modem Huawei E392 (Megafon) with an amplifier is connected to it. Communication is not always stable. As I understand it, when the signal is lost, the modem does not reconnect.
I wanted to write a script that would periodically ping Google and restart the router or modem if the signal was lost, but I can’t find a place where I can save this script so that it doesn’t get overwritten when the router is restarted.
Can you suggest how to solve the problem? If the script helps, then how to write it to the router?

Answer 1

If you have Asus flashed with dd-wrt, then part of the nvram can be assigned to jffs, where you can store your own scripts.