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The Internet

How Will Tonga's Broken Internet Cable Be Mended? (bbc.com) 62

Posted by msmash from the closer-look dept.
An undersea fibre-optic cable which connects Tonga to the rest of the world was severed during the eruption of a volcano. From a report: New Zealand's ministry of foreign affairs says it could take more than a month to repair breaks in the 49,889km (31,000miles) of cable that serves the South Pacific. The undersea eruption - followed by a tsunami - led to Tonga's 110,000 people being cut off. A 2G wireless connection has been established on the main island, using a satellite dish from the University of the South Pacific. But the service is patchy, and internet services run slowly. The cable, which is operated by Tonga Cable, is believed to have broken about 37km (23 miles) offshore. According to Reuters, fault-finding conducted by the company in the aftermath of the volcano seemed to confirm a cable break.

he process of mending it is actually quite simple, according to principal engineer at Virgin Media, Peter Jamieson, who is also vice-chairman of the European Subsea Cable Association. "They will send a pulse of light from the island and a machine will measure how long it takes to travel and this will establish where the break is," he explained. Then a cable-repair boat will be sent to the location of the first break. It will use either an ROV (remotely-operated underwater vehicle) or a tool known as a grapnel (basically a hook on a chain) to retrieve the broken end. That will be re-joined to fresh cable on board the boat and then the same process will happen at the other end of the break. If all goes well, the whole process will take between five and seven days. It will take time to get a cable repair boat to the archipelago and the closest one is currently stationed in Port Moresby, Papua New Guinea - about 4,700km (2,900 miles) away. The specialised ship, The Reliance, serves more than 50,000km (31,000 miles) of cable in the South Pacific.
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How Will Tonga's Broken Internet Cable Be Mended? More

How Will Tonga's Broken Internet Cable Be Mended?

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  • Headline makes it seem like they don't know (Score:5, Informative)

    by 93 Escort Wagon ( 326346 ) on Tuesday January 25, 2022 @03:31PM (#62206519)

    The actual text says "yeah we do this all the time, it's simple". But that doesn't generate clicks, I guess.

    • Re:Headline makes it seem like they don't know (Score:4, Informative)

      by mspohr ( 589790 ) on Tuesday January 25, 2022 @05:23PM (#62206883)

      The headline poses a question which a lot of people may have. How do you fix a cable? The article explains that it's not hard but there will be a long delay while a ship is positioned.
      Hardly seems like clickbait.

    • I've been living in Tonga for the last few years. A couple of years back we had a ship "accidentally" anchor drag the fibre in three different places, and were without internet for about 2 months while they did exactly the same repair as they are doing now. They had backup sat gear but being disused for some time some of the staff had taken some of the parts home with them (I shit you not), and they were lost. They claimed they would have another backup system in place to prevent a similar event again, but

  • Interesting, nothing on fire. (Score:4, Informative)

    by smap77 ( 1022907 ) on Tuesday January 25, 2022 @03:45PM (#62206545)

    Now that's some nerdy news that is palatable. With the constant stream of amped-up headlines I typically encounter, I thought they were going to have to lay a new cable from Singapore or somewhere, but no, it's just "This is how it is done". Boat, ROV, Splice, Done.

    Maybe next time: This is how Tonga's Undersea Cable will be Mended.

  • How do they connect? (Score:3)

    by lsllll ( 830002 ) on Tuesday January 25, 2022 @03:46PM (#62206551)
    Do they use a massive barrel connector x 2? Won't there be signal degradation?

    • It's fiber so they use optical splices and as I understand there are already splices every X number of kilometers where there are optical amplifiers so I imagine perhaps they add another amplifier in the chain or it's not a concern with the amount of splice needed.

      • I always thought they just had a magic smoke generating machine on the boat so they could pump it back into the cables where it leaked out.

        • Fiber doesn't contain smoke, newb. Fiber contains freakin' lasers. Why they don't just replace the cables with sharks, I'll never understand.

  • I don't quite get how they use time of flight to determine where the break is. Does the broken-off end of an underwater fiber create a reflection necessarily?

    • You get a reflection from any break.

    • Re: (Score:3, Informative)

      by Tim the Gecko ( 745081 )

      Yes, it reflects light back because there is a difference in refractive index between water and optical fiber glass. The wikipedia [wikipedia.org] article is rather technical, but this sums up what they are doing:

      Fiber break locators are intended to be low-cost instruments specifically designed to determine the location of a catastrophic fiber event, e.g., fiber break, point of high reflectance, or high loss. The fiber break locator is an opto-electronic tape measure designed to measure only distance to catastrophic fiber events.

      Lots of detail here [thefoa.org].

      • You can do this with all kinds of cables including coaxial. Also it only gives you the distance to the first break, you need to verify from the other end it’s just 1.

        • From the summary it sounds like they're measuring the distance from both ends and the splice will bypass any number of breaks in between.

    • Re: (Score:3)

      by bjwest ( 14070 )
      It works the on the same principle as RADAR or a TDR (Time Domain Reflectometer) for coax cable. Send a signal out (light pulse down the fiber, in this case) and measure how long it takes the echo to return after it hits the target. The target in the case of an OTDR (Optical Time Domain Reflectometer) being the break, where the difference in refraction bounces back a portion of the pulse.

    • Re: (Score:1)

      by Anonymous Coward
      I knew you get reflections (I've used a coax TDR), but fiber optic cables have amplifiers, so I didn't think that would work. Turns out the amplifiers are bidirectional. Neat!

    • Re: (Score:2)

      by jabuzz ( 182671 )

      Any dielectric discontinuity will create a reflection. Do they not teach Maxwell's equations anymore?

      • It's perfectly plausible that not everyone around here is a trained electrical engineer. Just the same as everyone around here isn't a geneticist, software engineer, aerospace engineer, astrophysicist, and bar-certified lawyer all at once.

        Take a breath and be a nicer person.

  • Welding. Repair it by welding. That’s my recommendation. There’s nothing a TIG welder can’t join together.

    • Welding. Repair it by welding. Thatâ(TM)s my recommendation. Thereâ(TM)s nothing a TIG welder canâ(TM)t join together.

      Your recommendation is mostly correct, but not TIG.

      Not necessarily this specific machine, but something of the sort: https://www.amazon.com/Mophorn... [amazon.com]

      I'd also like to agree with the previous poster who pointed out that the headline is obnoxious and intended to imply some major problem where none exists. Splicing fiber is routine, even on undersea fiber. It does require equipment and training, but a broken undersea cable is not a reason for hand wringing "how are they ever going to fix this disaster" headlin

      • It does require equipment and training, but a broken undersea cable is not a reason for hand wringing "how are they ever going to fix this disaster" headlines.

        It is expensive though, sometimes problems that are simple to identify and straight forward to fix are still difficult.

        • As it turns out, fixing undersea cables is a thing that happens all the time. The only reason this is going to take a while is because there isn't a boat equipped nearby, so they have to send one half way across the Pacific in order to do a fairly routine job.

  • New Zealand's ministry of foreign affairs says it could take more than a month to repair breaks in the 49,889km (31,000miles) of cable that serves the South Pacific.

    Given that Earth circumference is roughly 25,000 miles, that cable must take a lot of detours if its length is 31,000 miles!

    Or maybe, just maybe, 31,000 miles accounts for more than one specific cable that needs to be fixed...

    • Re: (Score:3)

      by grcumb ( 781340 )

      New Zealand's ministry of foreign affairs says it could take more than a month to repair breaks in the 49,889km (31,000miles) of cable that serves the South Pacific.

      Given that Earth circumference is roughly 25,000 miles, that cable must take a lot of detours if its length is 31,000 miles!

      Or maybe, just maybe, 31,000 miles accounts for more than one specific cable that needs to be fixed...

      Yes, the actual cable in question is a direct connection between Suva in Fiji and Nuku'alofa in Tonga, a distance of about 750km, give or take.

    • I'm guessing there's a whole bundle of them, which would normally give redundancy in case of a cable break. However, when something of this magnitude happens, there's little parallel redundancy that is going to get the job done.

  • ...5 hours on the support helpline later (Score:3)

    by bugs2squash ( 1132591 ) on Tuesday January 25, 2022 @05:25PM (#62206899)
    are the lights on the modem on, is it powered up ? Our technician will be onsite some time between 5am Monday and 3pm Sunday please be sure to be at home when the tech calls.

  • No surprises for Those Who Know (Score:5, Interesting)

    by AlanObject ( 3603453 ) on Tuesday January 25, 2022 @05:30PM (#62206915)

    For anyone even remotely interested in the history and technology evolution of undersea cable, you can hardly do better than Neal Stephenson's epic essay [wired.com] in Wired on the subject even though it is more than 15 years old.

    Recommended reading for anyone who aspires to technical literacy.

  • This is where my major in underwater basket weaving comes into play! Well, who's laughing now?

  • Duct tape will fix anything, even stuff that isn't broken!

  • ...Super glue and duct tape.... duh!

  • Duct tape fixes everything
  • Where's Musk's Starlink?

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