How It Works
Pull up the wrong undersea cable, and the Internet goes dark in Berlin or Dubai. See our animated infographics of how the web works!

Webmaster John Rennie and "the Beast" aboard the Wave Sentinel in the port of Dorset, England Jonathan Worth

For the past five years, John Rennie has braved the towering waves of the North Atlantic Ocean to keep your e-mail coming to you. As chief submersible engineer aboard the Wave Sentinel, part of the fleet operated by U.K.-based undersea installation and maintenance firm Global Marine Systems, Rennie--a congenial, 6'4", 57-year-old Scotsman--patrols the seas, dispatching a remotely operated submarine deep below the surface to repair undersea cables. The cables, thick as fire hoses and packed with fiber optics, run everywhere along the seafloor, ferrying phone and Web traffic from continent to continent at the speed of light.

The cables regularly fail. On any given day, somewhere in the world there is the nautical equivalent of a hit and run when a cable is torn by fishing nets or sliced by dragging anchors. If the mishap occurs in the Irish Sea, the North Sea or the North Atlantic, Rennie comes in to splice the break together.

On one recent expedition, Rennie and his crew spent 12 days bobbing in about 250 feet of water 15 miles off the coast of Cornwall in southern England looking for a broken cable linking the U.K. and Ireland. Munching fresh doughnuts (a specialty of the ship’s cook), Rennie and his team worked 12-hour shifts exploring the rocky seafloor with a six-ton, $10-million remotely operated vehicle (ROV) affectionately known as "the Beast."

Long Arm of the Beast

The Beast is like a lunar lander on steroids. Working at depths of more than a mile, it can trundle along the seabed on caterpillar treads or, when its thrusters kick in, skim above canyons like a hovercraft, at a top speed of three knots. Rennie and his team of six control the Beast via a joystick, using its sonar, video cameras and metal detector to locate damaged cables. Plucking a cable from the ocean floor is akin to picking up a piece of thread in a blizzard while wearing a catcher’s mitt. Currents can be fierce, which makes it difficult to hold the Beast steady above the cable. Visibility can be close to nil, which means that even finding the cable in the first place can be a long and frustrating process of trial and error. But according to Rennie, "gripping and cutting is the trickiest." This delicate piece of submarine surgery has to be performed quickly and cleanly, using only a murky video image as a guide.

When Rennie found the U.K.-Ireland cable--fishermen had cut it after it became entangled in a dragnet--the Beast’s manipulator arm grabbed it, sliced it clean, and brought each end to the surface. On board the ship, the cable was repaired and x-rayed (Rennie needed to make sure the splice was set right, as with a broken bone), then tested and lowered to the seafloor. "There is no time for celebration when we fix a cable," Rennie says. "There is lots of pressure from cable owners to move quickly. They are losing revenue."

Most cable breaks go unnoticed by users. Maybe a YouTube clip will take someone a nanosecond longer to download, but that’s about all anyone might notice when a single cable snaps. There are so many different lines connecting so many different places—a map of the network looks like the inside of a baby grand: strand after strand of cable stretching across the ocean floor like so many piano wires that service providers can usually reroute around any break. But if several cables snap in chorus, as they did several times in the past two years, big problems result.

Last December 19, when three cables under the Mediterranean Sea were damaged, Internet service began to wink out across the Middle East and parts of Southeast Asia. Egypt suffered terribly, losing as much as 80 percent of its network. E-mail and Web access were disrupted in Saudi Arabia and other Gulf states, while services fluttered in countries as far away as Malaysia and Taiwan. India’s enormous outsourcing industry—the customer-service backbone of the Western world—was also hampered, with the humble fax machine making a brief but crucial comeback until traffic was rerouted around the breaks. The same thing had also happened in January and February, disrupting Internet access to homes and businesses throughout the region for days.

The incidents reveal a surprising fact about the Internet: that it requires constant physical maintenance. Without people like Rennie patching cables, the entire network would gradually stop. First, traffic would slow to a crawl as more bits crammed into fewer and fewer cables. Then, after a while, isolated service failures like the ones in the Middle East would pop up. Eventually, as line after line went dark, U.S. businesses would be cut off from their outsourced functions abroad, international e-mail traffic would halt, and global financial transactions would cease. Pockets of connectivity would persist, but ultimately the Internet we rely on to stay in touch with the rest of the world would be reduced to the local-area network in your office.

On the next page, see our animated graphic of how the web works.

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122 Comments

On the 'World Map' in the 'How the traffic flows' display, why is there no mention of bandwidth in/out of Russia?

Being cut off from customer service in India no I would not be bothered by that at all.

I think it might have been better if they left those lines broken and pulled up all the cable.

I found the articles on the Internet and the Inkjet printers fascinating; two things that we use daily; sometimes when I see the cover of the magazine I believe it should be called PopSciFi, I understand that you need to capture peoples attention but there is plenty of wonderful things already in use that people do not know how they work, I will give you an example: my inexpensive watch that is synchronized daily with the atomic clock (Is that wonderful or what?).

Truly yours
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Marustkl, I hope I spelled your UN correctly? Small "l's" and "i's" play games with my vision.
So odd when I decided to turn on my PC, go to Pop Sci, and find pages 50-1. My actions for doing so were, (1) could not find Australia and, (2) no Russia either.
Of course page 1 on the NET brought me to your question first. That was when I noticed "Sydney," but still no Russia. Strange!
You would think there would be some interesting views and info with Russia, Alasaka, and the Bering Strait!
Of course in my interest to comment after seeing yours', I logged right in and typed this without finishing the article, Yet! I hope I'm not eating shoe in a few minutes, I very seldom comment on anything and I'm still wondering if I'll learn from my hasten urges, or go back to my "NO"= opinion/comment/question attitude?
Sincerely

Your caption is wrong, Dorset is a county, not a port.

just wanna say great article! i had no idea the internet was that hard-wired around the globe.

to stop terrorists from disrupting the internet by destroying the cables wouldn't it make sense to have all the cables linked so they would destroy their own internet capability

Your article was very interesting and informative; but as I read the article; I couldnt help but wonder if you are giving future terrorists another avenue in which to disrupt the world.

very usefull article.

who protect internet? we all must keep the internet

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You would think there would be some interesting views and info with Russia, Alasaka, and the Bering Strait! if you are giving future terrorists another avenue in which to disrupt the world.

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I wonder if cookie-cutter sharks can also disrupt these cables as well. I have heard they can reek havoc on power cables (they cut out the insulation).

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Your actulally quite right. The internet is a collection of networks not necissarily IP based. A majority of attacks exist on the IP side. Wide area networking technology carries all traffic regaurdless of the payload. If there is an attack on the border of your internal IP network the WAN cares not. If your border is penatrated and a connection is made to create another network, again the WAN doesn't care. Can the internet be taken down? Not if you have skilled and knowledgeable Information Security officers maintaining the network you reside on.
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If there is an attack on the border of your internal IP network the WAN cares not. If your border is penatrated and a connection is made to create another network, One latest thing for all of you guys, their a campaign started by a university here is a link of it. kindly check it its really useful i think.
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The map on the 2nd page is not correct. Where's Russia and Eastern Europe?

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Your actulally quite right. The internet is a collection of networks not necissarily IP based. A majority of attacks exist on the IP side. Wide area networking technology carries all traffic regaurdless of the payload. If there is an attack on the border of your internal IP network the WAN cares not. If your border is penatrated and a connection is made to create another network, again the WAN doesn't care.

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A big thanks to engineers like John Rennie who work round the clock to ensure that we continue to have the internet connectivity that we most depend on for our 24 X 7 online global communication. I didn't even realize that it is the undersea cables, that carry phone and Web traffic from continent to continent at the speed of light, which made this possible. Full marks to James Geary for providing this mind boggling revelation.
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Really, I believe the search engines are solely responsible for protecting innocent children and other dangerous aspects of the Internet. They use an algorithm that keeps the quality sites on the top 10, while keep the dangerous, pornographic, violate, adultery information at a minimum, unless of course you search it up, while kids won't do most likely at a YOUNG age.

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I never really thought about how the internet was linked around the world... this was very informative and eye opening.

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When will satellites eliminate this cabling need running around the world? It seems like this hard wire could be a good backup for the future to satellite transmissions. Just a thought...?

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I wanted to know more of the internet linking, and this article was very very interesting for me ...
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It's interesting to be reminded of the actual physical underpinnings of the internet from time-to-time. As much as we focus on what is virtual, whether shopping, dating, news, etc. there is always something and someone in the real world keeping the plates spinning.

Thanks for the interesting article.

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It’s frightening how much we have all become reliant on the internet for communication, trade and our general safety. I dread to think what would happen if a natural disaster destroyed the cables beneath the North Sea; it would have a knock on effect of tremendous damage to the western world. I hope there are plans for a backup system as we have already seen the disruption a few damaged cables can cause next time we might not be so lucky.

Very though provoking article.

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It is great that they use remotely operated submarine deep to repair underseas cables which are vital in connecting continents across the vast oceans. The article shows how interconnected we are and why the wrong cut in the cables could greatly impact one or more countries.

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What a fascinating article - I had always wondered how the internet was connected between the UK and and the US - now I know! http://thecostablancapropertyguide.com/costa-blanca-repossessions.html

great article. Most people would be surprised to see the size of the cables connecting continents.

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A big thanks to engineers like John Rennie who work round the clock to ensure that we continue to have the internet connectivity that we most depend on for our 24 X 7 online global communication.
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Why is the internet so writing intensive rather than being photo-intensive?

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I dread to think what would happen if a natural disaster destroyed the cables beneath the North Sea;
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A majority of attacks exist on the IP side. Wide area networking technology carries all traffic regaurdless of the payload. If there is an attack on the border of your internal IP network the WAN cares not. If your border is penatrated and a connection is made to create another network, again the WAN doesn't care.
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I never thought that many countries are so dependent on some cables in the sea! So we have to trust in "The Beast"! Great article, very intresting.

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I don't think anyone protects the Internet. Some days I wish there was some kind of oversight, but then there are some I don't ;-)

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He's a nicely tough guy. He risks his life for the sake of all people.
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I have experienced the problem of Internet cut!! The people who risk their lives to make it working are really great.

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would be pretty scary if the internets went down and I couldn't play any more games :(
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This man is my hero! I lke this artice thanks a lot

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I like this article.
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Man, I didn't know that most of the internet is hard wired underground. Amazing.

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The Internet is not secure. But it is growingly so as people (experts) keep updating and working hard to enhance the security.
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Thank you. The Internet still has to focus a lot to ensure better security. many cases of cyber crimes are still happening anywhere. Brooklyn Locksmith

In fact, did you know what happened when Vizag Cable Landing had torn off the connectino between India nad Singapore? It was a disaster.

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I think the internet has evolved into something extremely important. With so much information being passed around there's bound to be vulnerabilities.

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Fascinating! I never knew cables ran at the bottom of the ocean. it's funny because the internet is out of sight, how it works truly is out of mind.
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Google will dominate this in a few years..

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the internet is a very cool thing but who knows how long it can last....

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wow. you don't realize what kind of work it takes to keep the internet going.

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Great article. I didn`t mention what it takes to get the internet working

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It's very helpful for us.Thanks.
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thanks. very usefull article.

who protect internet? we all must keep the internet

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Great article, very helpful. Thanks

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What about this new law i keep reading about?
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very usefull article. Thanks...
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Wow thats a bit scary to think that the internet could just go out like that. If that happens in my area i wouldn't be able to make any money on the internet for a while. My whole business depends on the internet up and running.

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It is great that they use remotely operated submarine deep to repair underseas cables which are vital in connecting continents across the vast oceans.

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Great article! thanks for sharing... It is surprised to see the size of the cables connecting continents.
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Cyber attacks, adult content and all negative aspects of the internet will always exist. It's really up to us how the internet will continually grow and influence kids.
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I ageere with you (Zauberer De Pasco)

Great article. I didn`t mention what it takes to get the internet working.

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Are there any organizations (formal or informal) that take an active role against bots, such as counter-hacking an infected machine to repair flaws (forced vaccinations)? I’ve read about the Air Force planning to have its own ‘bot network’ to do battle with other bots, but I’ve always been curious if it would just be easier to set up honeypots that repair infected machines.

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I think the internet has evolved into something extremely important. With so much information being passed around there's bound to be vulnerabilities. But why these cuts are there?

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the internet definitely needs to be watched.
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I thought google was the only one protecting the internet
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Yes,absolutely agree with you and everybody should contribute a little bit to the internet.
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Great article! thanks for sharing... It is surprised to see the size of the cables connecting continents.
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I abosolutely agree with you but i am feeling scary that internet is going to disappear...
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Thanks for this great informative article about "Who Protects The Internet" - till now no idea about this..Thanks for sharing..
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Nice article.
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No one will be able to protect the internet from Americans now that obama is looking for powers to shut it down as and when america feels threatened
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When internet goes down even for 1 day there will be loss of billion of dollars. As there is no one who owns the internet it is understanding between various parties to maintain the internet equipments.
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That machine is very great, he use it to protect the Internet?
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Surely we should be looking more towards satellite technology rather than laying cables beneath the sea. From day one the cables will be begin to degrade in such an environment, so its not the ideal long-term solution.
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That machine is very great, he use it to protect the Internet?

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That machine is very great.

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Very interesting article. The title had me hooked and of course the picture is really cool. I had no idea there were cables running underneath the sea:)
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I wish I had mod points today, I would mod you insightful.

It can't be protected without having control of it.

The single best thing about the internet is that no one has full control of it. Had it been controlled by government or industry, it would be a miserable little shadow of what it is today.

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Great Article. Good to see some one is helping
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This is a very interesting article. I had no idea that cables such as this existed!

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The only way you can see porn and stuff is if you actively turn off the filter, search engines do a good job protecting the internet imo

I believe the search engines are solely responsible for protecting innocent children and other dangerous aspects of the Internet. They use an algorithm that keeps the quality sites on the top 10, while keep the dangerous, pornographic, violate, adultery information at a minimum, unless of course you search it up, while kids won't do most likely at a YOUNG age.

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I guess I'm one of those people who thought that in this day and age we wouldn't be using cable for the internet anymore. I figured we would be bouncing things off of satellites by now.

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Google controls and protects the internet :P
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It's amazing to imagine the amount of maintenance that the internet requires.
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Ver interesting article! Thanks for sharing!

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The internet is a collection of networks not necissarily IP based. A majority of attacks exist on the IP side. Wide area networking technology carries all traffic regaurdless of the payload.. If there is an attack on the border of your internal IP network the WAN cares not. If your border is penatrated and a connection is made to create another network, again the WAN doesn't care. Can the internet be taken down? Not if you have skilled and knowledgeable Information Security officers maintaining the network you reside on.

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There are usually redundant or backup links built for certain paths. Even though frequent cuts or disruptions to any line may happen, the user experience may not be drastically impacted. Perhaps just a little longer than it takes to route to a secondary route. What's interesting to me in this article is the pic of the undersea installation! I have never seen it before.

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Great article..interesting one..very informative.. Thanks for sharing :)

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Being cut off from customer service in India no I would not be bothered by that at all.

I think it might have been better if they left those lines broken and pulled up all the cable.

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What a fascinating article - I had always wondered how the internet was connected between the UK and and the US - now I know!

So we have the NSA, CIA, Federal Agencies and probably other dark closet types, all are now scaremongering around the security, social dangers, likely terrorist mis-use and dangers of having freedom of expression (amongst others) without constraints and control.

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Can the internet be taken down? Not if you have skilled and knowledgeable Information Security officers maintaining the network you reside on.
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The internet can not be affected in that way.
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I didn't even realize that it is the undersea cables, that carry phone and Web traffic from continent to continent at the speed of light, which made this possible.
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It is great that they use remotely operated submarine deep to repair underseas cables which are vital in connecting continents across the vast oceans.

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amazing, its not often you thin kabout things like this when you wait on your emails going back and forward

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Wait tell we get a solar flare...that will be worst!
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These deep sea cables seem like an obvious target for terrorists

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What's to stop Al Qaeda from targeting these?

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There were some additional links to internet security I noticed.

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