Interesting experience, this has happened twice now. When house looses power I am still online now that I have moved to Fiber.
It feels a bit eerie. My network and computers, TV, media center, etc are all on UPS so they just keep going. Things just get really quite which is interrupted by just the periodic beeps of the UPS systems.
Does anyone know why my new Fiber connection does this but my old system which was bonded DSL did not? I know back in the early days of DSL I could do this, but some where along the way it stopped being power outage resistant.
Your fiber ONT box (where the fiber signal gets converted to copper ethernet) probably has a backup battery in it. This is especially useful if you have VOIP landline phone service through your fiber provider so you can call for help if necessary when the power is out. You or your provider will need to replace this battery every few years, just like with a UPS.
In my case the NID is in the basement and connected to my own UPS that powers everything on my main comm panel.