– Fibre optic and electricity.

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What has my fibre optic internet (transmits using light frequency) have to do with electricity ? Hydro good out miles/kms away – not affecting our household, yet my internet goes out, why?

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6 Answers

Anonymous 0 Comments

One end of a fiber connection is converting an electrical signal into light, and the other end converts it back into electricity. If a hub or server essential to your internet connection goes dark due to the power going out, there goes your internet as well.

I feel like internet infrastructure being only powered by a hydro dam is very odd and bad design, but what do I know about your local area.

Anonymous 0 Comments

>What has my fibre optic internet (transmits using light frequency) have to do with electricity ? Hydro good out miles/kms away – not affecting our household, yet my internet goes out, why?

You do not have a direct fibre optic cable connection to… likely *anywhere*.
Before your ELI5-question arrived on whatever reddit server it resides on now it had to traverse many – possibly dozens of – relays and distribution nodes.
And if any stops on your connection’s way to the rest of the world fail without alternative routing paths… well, then you connection to the rest of the world fails.

Anonymous 0 Comments

Fiber internet works by converting the 1s and 0s that make up a normal internet connection into 1s and 0s transmitted over light. In the simplest form, a light turns on and it’s 1, a light turns off and it’s a 0. In most fiber optic systems, this is done with a laser and a detector that converts electricity into light and vice-versa.

Even though the cable itself carries no electricity, you still need electricity on either end of the connection to drive the laser and the detector. If whatever is on the other end of the cable loses power, the connection stops.

Now, most internet service providers operate on both power from the power grid and power from backup generators that typically run on diesel fuel. If the power grid were to go down, internet service provders have a backup in the form of both massive batteries and diesel generators. It takes a few minutes for a diesel generator to spin up, and during that time an internet service provdier still has to keep the connection flowing so they fall back on massive batteries. These batteries that they fall back on are literally massive banks of what are essentially giaganitc car batteries, providing enough power to keep everything powered until the generators take over powering everything. These batteries might only last a few minutes, but with the generators being there, that’s all a service provider really needs.

But. In some situations even the diesel generators might not offer enough power to keep absolutely everything up and running for the entire duration of a power outage. Instead, companies have to prioritize what equipment gets power and what doesn’t. In many cases, the fiber optic lines that are running to “critical infrastructure” like government buildings and cellphone towers are powered with a higher priority than individual customers. This means that occasionally there are situations in which customers will lose internet service (even over fiber optic cables) during a situation in which a power outage lasts a long time. It helps keep the critical things running for longer.

Now, this might not be the case with what’s happening in your situation. It sounds like your internet service provider just has a smaller issue preventing you from getting a connection. Most service providers have at least two different connections to the power grid to prevent situations like yours from happening. It just depends on what service points the fiber optic cable to your home passes through to get to you. Light can’t travel forever so sometimes there are signal boosters that require their own power, and something might have gone wrong. It all really just depends on the infrastructure of your particular service provider.

Anonymous 0 Comments

The simplest way to view it is, ironically, to think of it like the actual street/highway system. If you live on a small dirt road out in the middle of nowhere, then a big problem that requires road ~~destruction~~ *construction* can cause huge problems for you being able to actually get to your house. If, on the other hand, there’s road construction on some major thoroughfare through a city, there’s *usually* a bazillion other ways to get to where you’re going, they just take longer or require more left turns or the like.

So if any problem occurs at at any of the “early” stages of your connection (before it gets into the wider internet infrastructure), you may be stuck, because there’s only a very small number of routes to get to *your specific house,* even though there’s a bazillion ways to get from Information Highway 5 to Any Random Web Address.

Anonymous 0 Comments

> not affecting our household

But is it also not affecting the ISP building on the other end of your fibre cable?

Anonymous 0 Comments

Fibre itself is just a light-tube, there are no electronics.

At each end are lasers and light detecting circuits. Powered by electricity.

Often the fibre run is to a local cabinet where it’s converted to electrical signals and then put down a different, better type of fibre that can travel many kms. That fibre then ends in… more electronics that do the same, and those are connected to things that do the same, and so on, around the entire world.

But your house fibre – if indeed it is fibre, because there’s a lot of misselling – is only a small local run. The actual fibre that connects you and a thousand other users back to a central hub will be local to you, and powered by electricity.

This is one of the things I have to explain to employers on a regular basis, for even “local” networks (i.e. a few hundred metres in either direction). Because the switches we used to deliver networking to the copper cables in your office and the wireless access points are almost always connected to each other by fibre (fibre doesn’t allow electricity down it, so you use fibre connections between buildings to prevent different electrical phases from allowing current to flow between the equipment and potentially starting fires or damaging equipment).

But they are powered by electricity, so if you have too many things in the critical network paths that are all reliant on power, things go off when something in the middle goes off.

In many workplaces, I have actually enforced that we do this:

– Switch A is connected to Switch B with fibre.

– Switch B is connected to Switch C with fibre.


– Switch A is connected to Switch C with fibre.

This means that if the equipment running Switch B goes off, there is still a fibre-only-path between A and C. So long as A and C stay powered, they will stay connected to each other, even if B is off.

And this usually works out very simply because the fibres between A and B, and those between B and C will already have – say – 16 individual fibres in them.

I run 8 of those fibres directly to B, where it connects to the switch and converts the signal.

I run the other 8 directly into the 8 of the other fibre that’s going to C. Now there is a path that is entirely fibre between A and C and B can turn off without affecting it.

But still if A or C turn off, we lose the data in the fibre because one end isn’t powered to send/receive the data. So what you do is just extend this scheme in madly-connected ways.

A -> B -> C -> D -> A.
As well as B->D, A-C, etc.

Now any one switch going off makes no difference to the rest of the network because they’re all connected via fibre paths to some other switch which IS powered.

Every time I inherit a network, it’s designed like your local ISP network. One connection from you to some equipment, and that cabinet is reliant on a connection to more equipment and so on, with little resiliency or redundancy in it.

And every time I explain to my team what we need, and start building out, by the time I leave a site, every points is heavily connected to each other INCLUDING using fibres to just bypass certain switches. It costs almost nothing, in the grand scheme of things.

Because fibres are amazing and can connect you to equipment that’s literally kilometres away… but it’s all dependent on both ends having power to read/send the signal over the fibre.