Re: A basic approach
My previous ISP supplied me with an AIO router/modem device which they managed.
Solution: I plugged my router into one of their device's ethernet ports. Never had any issues for 3 years. I switched ISPs for one that let me purchase my own modem. Best part: Didn't have to make any changes to my LAN since I am using the same router, no passwords/SSIDs had to be modified unless I wanted to.
I hope most Reg readers here use their own routers rather than ISP supplied. Makes life easier especially when troubleshooting connectivity issues.