[mlyle]

So, for clarity, it's never one fiber line being cut. It's a big massive bundle of fiber carrying different circuits for different carriers different places that were run in the same trench and all got cut at once.

Then they get to dig it out better and someone gets to get down in the hole and figure out which piece of fiber needs to be spliced to which other one.

Because of DWDM, some of those individual fibers may each be carrying 64 channels that in turn each carry 400gbit/sec for different providers/services/etc.

[korethr]

And when it's a large bundle cut, it's going to take a bit before service is restored. I have been told that a highly skilled tech can splice a single strand in a matter of minutes. Looking it up, I find figures of an average of 30 minutes per joint for 4-strand bundles, and slowing down from there. So if you have a 144-strand bundle to repair, or multiple 144-strand bundles, it's going to take several hours to effect the repair, and you're probably going to have to rotate through techs to avoid fatigue-induced errors slowing things down even more.

[fcsp]

Would it maybe be an idea to, going forward, color the cables individually before putting them into the ground?

[jzwinck]

Of course they are colored. Like this: http://www.evertopcomms.com/144-fiber-count-gyts-fiber-optic...

It is still a lot of work, and so far not automated.

[bobthepanda]

It is also, as a matter of practicality, going to be very difficult to find 144 colors that can‘t be mistaken for one another, particularly in conditions that i would imagine wouldn‘t have great lighting.

[Hydraulix989]

Well, the layout has them grouped into colored sub-bundles.

[Scoundreller]

If they’re all in use and it’s point to point, might be easier connecting whatever to whatever. Then simultaneously swap line cards around as they get lit up or letting IP do its thing.

Source: I have no idea.

[korethr]

Not as feasible as it sounds initially. I don't know if you've ever looked inside a cat-5/6/whatever networking cable[1], but if you do, you'll see that it is actually a bundle of 8 individual wires, in 4 twisted-together pairs, color coded. Those different wires carry different electrical signals, and if the various signals are not supposed to be on the various wires they are supposed to be on, the connection won't work.

So imagine if you cut a Cat6 cable in half, and then spliced the individual wires back together without regard to which wires you connected. Very likely, Pair 1 negative is connected Pair 3 negative, Pair 2 has its polarity reversed, etc, and so the network link never comes online.

At the individual device level, fiber cables are connected in pairs, in a crossover fashion. Device A Tx connects to Device B Rx, and vice versa. So with a random splicing, you would end up with pairs getting crossed or broken up, invalidating the connections and labeling of every patch panel downstream, making for yet more work than the initial work of splicing the cut bundle.

1. Not impugning your intelligence, knowledge, or character here, some people never have because they've never needed or wanted to, and that's totally okay.

[srswtf123]

You must be joking. Cables are Color-coded and labeled obsessively.

You should take some time to understand the physical layer of infrastructure. There will always be work to do in meet-me-rooms!

[jeremyjh]

This. Even if you have redundant lines with multiple providers there is a good chance they are part of the same fiber bundle. It can be really difficult to get providers to admit who they are leasing from and what the physical runs are.

[mikem170]

And then telco's may move leased fiber to other paths without telling customers, messing up the physical redundancy they thought they had...