Repair Crews Reach Vicinity of Damaged Cables In Mediterranean 145
GWMAW writes "A robotic submarine searched beneath the Mediterranean on Sunday for damaged communications cables, two days after Web and telephone access was knocked out for much of the Middle East.
Telecommunication providers from Cairo to Dubai continued Sunday to scramble to reroute voice and data traffic through potentially costly detours in Asia and North America after the lines running under the Mediterranean Sea were damaged Friday." According to the article, "Once found, the cable ends will be pulled to the surface and repaired on deck — a process that could take several days."
Dang! I was getting SUCH a good deal (Score:5, Funny)
Dang it! I was getting SUCH a good deal from the colocation facility in Yemen.
Wow (Score:5, Funny)
How do they do it? (Score:5, Interesting)
How do they repair the cables? Especially with glass fibre I wouldn't know what to do.
Re:How do they do it? (Score:5, Funny)
> How do they repair the cables?
Superglue and duct tape.
Re:How do they do it? (Score:5, Funny)
this is for UNDER WATER use.
therefore, its better left to DUCK tape.
(sorry....)
Re:How do they do it? (Score:5, Informative)
Luckily you can have both in one :)
http://duckproducts.com/products/detail.asp?catid=1&subid=1&plid=3 [duckproducts.com]
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Surely not! We all know here that ducks float.
Re:How do they do it? (Score:5, Funny)
Surely not! We all know here that ducks float.
Only if they weigh the same as a witch!
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Red Green [wikipedia.org] to the rescue!
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I'm sure it's possible to cut off clean ends and put a replacement between, possible install a repeater in between. The beam already has to be extremely powerful to cross hundreds of miles, another cut shouldn't cause too much attenuation.
I just hate to think what happens if this happens too many times, they'll have to lay a whole new cable.
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how do you propose to power it?
I'm not saying power couldn't be supplied, but I don't think it'd be cost effective, and you'd need to run a whole new set of lines.
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Re:How do they do it? (Score:5, Informative)
Actually, there are repeaters in line, albeit I don't remember the distances. There's a big copper conductor in the jacket (just one, the ground is the ocean itself) sending a couple hundred volts through it.
Re:How do they do it? (Score:4, Informative)
how do you propose to power it?
I'm not saying power couldn't be supplied, but I don't think it'd be cost effective, and you'd need to run a whole new set of lines.
The same way the repeaters are already powered - the are power leads bundled with the fiber cable. In a full cut, they would have to repair the copper power leads anyway.
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I didn't know they already did that.
Taking on the GP's reply to my post...
I guess that's what a Biological/Computer Science major gets for posting on an electrical/(civil?) engineering topic.
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You'd still have to dismantle the cable and clean up the fibres anyway. An anchor is not going to make any kind of clean cut. So the task of splicing an any kind of repeater is going to be just as complex as joining the cable back together. Even before you consider the problem of powering that repeater.
Re:How do they do it? (Score:5, Informative)
The actual fiber repair is done pretty much as it would be done for terrestrial cables. Either a fusion splice, usually by re-cleaving the ends for a clean surface and vibrating the ends ultrasonically to heat by friction and weld them together, or a very small splicing kit that holds the ends in near-perfect alignment, usually filled with a gel of identical optical properties to reduce the loss and refraction. Since space is an issue, I suspect fusion splices are the only acceptable option.
The biggest problem is both accomodating the repairs to the fiber jackets, and then re-sealing the cable. I wouldn't be suprised that there are fairly standard splice boxes that solve this.
Replacing segments doesn't seem like a good option. Any useful segment should measure miles in length, which is pretty expensive. Even replacing a segment and hauling the old one in for repair sounds like more trouble than it's worth. Of course, repairs on the open sea sound like fun to me. I had enough trouble sitting at a little worktable in a dim cable room with equipment balanced here and there, and testing going on constantly. A nice 20-30 foot sea would make me want to apply at the local McDonald's. Life is too short.
But nice work if you can do it.
Re:How do they do it? (Score:4, Informative)
Fusion splices are the only acceptable option because you can't afford to have a 0.1 dB splice on a long fiber. Too much loss will upset your whole link budget and you will not get an acceptable SNR at the far end.
BTW, I have never read how a fusion splicer works, but all the ones I have used align the fiber and look like they send a current between two metal contacts for ~0.2 seconds that fuse the fiber. I'm pretty sure ultrasound isn't used. When you are trying to align two fibers exactly, vibrating them doesn't sound like a good idea.
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But nice work if you can do it.
No it's not.
I dunno how things work on cable ships for other countries, but working on the USNS Zeus [fas.org] sucks bigtime.
No internet, no phones, no email, not even any outgoing traffic. NO electronic emissions of any kind. That also includes satellite TV because the dish does emanate some EMF. The only thing you can get is US Navy fleet broadcast coming in on UHF or EHF. You're gone for 3-4 months at a time, nobody onboard except for the captain knows where you're going or when
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The things you describe sound like military paranoia. I imagine things would be better on civilian repair ships.
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So, after a nudge, nudge you get a wink, wink? Does that make the cable a goer?
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new windshields? *confused*
Re:How do they do it? (Score:5, Funny)
Don't worry, you don't have to do a thing. They already have people who do know what to do.
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That is why you are not doing it.
I am not an expert myself. However Glass does Melt, and can be fused back together, is a possibility, or the ends polished and put right next to each other... Perhaps there is a lot of Dark Fiber built into the cable to be bypassed. Humans made the technology, they probably know how to fix it.
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Stuck together with a glue having similar optical properties IIRC
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A typical rule of thumb is to bundle twice the number of fibers that you actually need. In an undersea cable, I wouldn't be surprised if they include four or even ten times what is needed to take occasional breaks and even future expansion into account. However, no amount of dark fiber will help when the whole bundle is severed by saboteurs^H^H^H^H^H^H^H^H^Hanchors.
MacGuyver uses a Swiss Army Knife, and this: (Score:2)
http://en.wikipedia.org/wiki/USS_Jimmy_Carter_(SSN-23) [wikipedia.org]
Re:How do they do it? (Score:5, Informative)
How do they repair the cables? Especially with glass fibre I wouldn't know what to do.
My assumption would be that there are points built into the cable where you can exchange out bad segments for new segments.
Re:How do they do it? (Score:4, Informative)
http://www.laser2000.co.uk/fusion_splicers.php?area=262
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It would be interesting if they could build a cofferdam to house the bad ends and conduct repairs in it.
Say each segment is some 300 feet long. One or more cofferdams of such length could be built and kept on stand-by. When a cable is damaged or cut in some way, the cofferdams (maybe similar to a submarine or coffin with hinges on one side so that the other open and close to admit the cable. The bad ends would be trimmed off and given new ends, and the cofferdam unlocked and flooded and dragged aside, or th
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Not really that useful. A cofferdam will just slice the cable just outside the wall when you drive the steel elements into the seabed. Also, it'll take weeks or months to set up and break down, and doesn't work in water deeper than a few hundred feet, anyway.
Now you could use a caisson or dive bell to do the repairs, but then you have the issue of damaging workers' health in long saturation dives, and you have to spend long time getting guys up and down to the work site.
The best option is the one they do
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To the contrary, the existance of submarine taps are very well established. [wired.com]
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How do they repair the cables? Especially with glass fibre I wouldn't know what to do.
http://www.francetelecom.com/sirius/dossiers_anim/cables_sous_marins/index_en.html
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Re:How do they do it? (Score:5, Informative)
Optical Time Domain Reflectometer. You just ping the broken end and get a distance measurement.
Standard fare on good network testers (Score:3, Interesting)
I used to work at a network operations centre and we had testers that did all the kind of stuff. They'd tell you how long a cable was, what the loss was, if there was a break, info about the other end, etc, etc. Also could do layer 2 and 3 diagnostics. It was a real useful tool if a connection didn't work. Plug it in, see what looked out of place.
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Re:How do they do it? (Score:5, Informative)
With a device known as an Optical Time Domain Reflectometer [wikipedia.org]. Supposedly they can not only detect cable length, breaks, but even the location of splices.
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Indeed, any piece of fiber which isn't of very good quality will reflect part of the transmitted optical signal. By measuring these reflections with an OTDR like you said, you can pin-point the exact location of the damaged fiber. Even a splice of very good quality creates a little loss (about 0.10 dB), which you can measure.
Measurement with an OTDR is basically an optical radar. Send out an optical pulse and measure what comes back. Do some heavy math and you can plot signal loss vs cable length.
One hard p
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Well you can, in a way. A pulse of light will be partially reflected from the broken end and the round-trip time measured. You should also be able to detect the last repeater in each half and so isolate the break to segment between the repeaters. There is also copper wire in the cable to power the repeaters and it should be possible to figure out how far the break in it is from the shore station by several methods.
IMHO the operators need to give more thought to reliability. They need more space diversit
OTDR (Score:2)
http://en.wikipedia.org/wiki/Optical_time_domain_reflectometer [wikipedia.org]
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Actually, you can. You use a device called a Time Domain Reflectometer [wikipedia.org], which sends a pulse down the line and times how long it takes a reflection to come back.
2 * Distance = Speed of light * Round trip time
To find the location of the fault to within ten feet you need a timer with about a 20 nanosecond resolution, which equates to a 50 MHz counter -- not too difficult.
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sure you can. google OTDR (Optical Time Domain Reflection). You get a fraction of a second value and multiply * speed of light in a fiber and voila, #feet to break.
Wouldn't that be "#meters to break?"
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that depends what units your reference for the speed of light in the fiber (note: speed of light in a fiber is considerablly slower than the speed of light in free space) is in.
Re:How do they do it? (Score:4, Informative)
fiber splicers - its mostly done in the field because in house we have handy-dandy prespliced fiber cables of different lengths. If you see (fill in local ILEC) out repairing a cut cable, chances are they might be splicing.
Re:How do they do it? (Score:5, Informative)
How do they repair the cables? Especially with glass fibre I wouldn't know what to do.
They drag the cable up and cut it (assuming it is not already in two pieces). They strip back the armor and sheath on both pieces. They then splice in a new piece of cable using a fusion splicer, which basically lines up each individual fiber (quite a time-consuming process to clean and prep each piece) and then the fusion splicer essentially melts the fiber strand back together. They put heat-shrink and something like a splint to keep it from bending over the spliced area and then fit each splice into a tray. The trays are then mounted into a splice case. Submarine cables are much more difficult because it has to be well sealed and able to withstand significant pressure.
The faults are located using an OTDR (Optical Time Delay Reflectometry), which basically sends light down the fiber and measures the reflections. As we know the speed of light we can accurately measure the distance to a break, imperfections, etc of the cable and splices.
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They cut the cable in half, and put a new piece in it. They can locate the exact point of failure using an OTDR, as already mentioned in other comments by now.
In one such big under-sea cable, there could be hundreds of individual fibers inside. (It doesn't cost alot more to put another fibre in the big cable, and you get alot more bandwidth to sell).
For each fiber inside the cable they "weld" it to the new piece they are putting between. (I'm sorry, I don't have the correct translation for the word in Engli
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I'm wondering about the "pulled to the surface and repaired on deck" part.
I imagine a cable laying on the sea floor going more or less "straight"
from A to B. Is there enough slack in the line to bring the broken
ends to the surface and hold them together?
(Clearly, the answer must be 'yes'. But I'm just wondering if anyone knows
more about it. Do they intentionally leave in some slack just for such a
reason when they lay a cable like this?)
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If you think about it, given the long length of the cable compared to the depth of the ocean floor, you aren't adding much the total length of the run buy taking it to the surface. You could easily have some slack in the system to accommodate this. And of course, the cable is cut, so you might just add a new splice sec
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lift it and then melt the fiber.
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When the BT engineer installed my companies fibre based connection, they did this [youtube.com], it's probably just as awesome but on a larger scale.
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I would imagine by splicing each fibre and replacing the sheaths as they go.
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Ok, I'll bite.
Optical fiber cables are connected by first identifying each strand in the bundle, and the other cut end of that same strand. Matching strands are taken, one set at a time, into a fusion splicing machine. The fusion splicing machine aligns the strands, then heats the ends so the glass melts together.
Older splicing machines required the person operating the machine to visually ensure the strands were aligned, and the heating was automatic. New machines perform computer-guided alignment and a
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They use something called a "fusion splicer" to weld the fibres together.
and while you're at it (Score:1, Troll)
Slack (Score:3, Interesting)
Re: Slack (Score:5, Informative)
There was a terrific article written for Wired by Neal Stephenson (yes, that Neal Stephenson!) called Mother Earth Mother Board [wired.com] all about the laying of the longest underwater telephony cable in history. He goes into a lot of details as to how the cable is laid, what happens to the cable when it reaches shore, what is the cable made of, how does it work, etc.
Here's an excerpt where he explains how slack affects the process:
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I never knew laying cable could be so interesting.
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I'm sorry, I'm sure that was a really useful explanation, but I'm stuck on one detail -- there's a public beach named Tong Fuk??!!
Conspiracy Theory (Score:2, Interesting)
If I was a certain US entity who is worried about more and more internet traffic avoiding the ol' USA, I'd "damage" a cable while using the outage as a cover to put a tap a few hundred miles away. If anything goes awry while tapping the cable, the obvious damage will be labeled as the cause.
But that's just me.
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Yes, the operant question for me in this story is "did we/the CIA cut the cable, did some other entity do it, or was it an accident?"
Not a whole lot of clues to go on so far.
And I wish I had some links to stories of various cable capers we (the USA) have been involved in before show those encountering this possibility for the first time.
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Yes, the operant question for me in this story is "did we/the CIA cut the cable, did some other entity do it, or was it an accident?"
If that's what you're focusing on, then the operant question for you should be "is my tin foil thick enough?"
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Satellites FTW? (Score:1)
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~500ms Latency.
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Re:Satellites FTW? (Score:5, Interesting)
Yet another reason why we need a better satellite infrastructure. If everyone were using satellites, a reroute through Asia would be unnecessary.
Except for the whole "240ms minimum latency" thing. Also, it's a lot easier to fix a malfunctioning cable than a malfunctioning satellite. Also, bad weather over the Satellite NOC can take out everyone's connection.
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Geosychronous orbit has too much time latency, and LEO takes more satellites to cover the same area. It'd be cheeper to just lay more cable, but corporations tend to push for raw efficiency rather than redundancy. It's going to take governments using their buying power to encourage redundant routes to get us back to where DARPA was in the '80s.
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People don't like satellite links. Some people don't like then so much that they will hang up and re-dial hoping to get routed over a cable next try. The reason is the delay. Light is fast but geo-sync is high. It's annoying to have a lag in the phone conversation so cables are always preferred.
Not necessarily a single point of failure. (Score:2)
I don't think this is a single point of failure. Now, of course I didn't read the article, but according to this map [telegeography.com] of submarine communications cables, middle east has more than one cable reaching it.
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Given the all the frantic rerouting going on, as well as the similar problems faced earlier this year, we should assume that it is, in fact, a central point of failure, no matter what an abstract overview map tells us.
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The re-routing over the hours/days following the event is pretty much what would be expected given that theese are commercial links that companies have to pay to send thier data over.
Presumablly someone at each ISP has to do (perhaps only approximately and mentally) a cost-benifit analysis and decide that the cost of sending the data via an alternative route is worth the reputation saved by getting thier customers back online quickly.
Also afaict the middle east isn't the most politically stable of areas and
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And most of them are connected to the same city, where one ship can drag its anchor across all of them at once.
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then it might be worthwhile to invest in an underground tunnel or at least some kind of protective shielding under which the cables can sit. if it's a large network hub where 5-6 cables meet, then the cost of a little physical protection might be cheaper than the cost of losing huge segments of the network in addition to having to repair all those broken cables.
or, if the cables remain relatively stationary, you could install a radio beacon or GPS marker over the cable bundles so that large ships know not t
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then it might be worthwhile to invest in an underground tunnel or at least some kind of protective shielding under which the cables can sit.
I dunno. IANAE, but I can imagine that whatever would be strong enough to protect the cable from being torn up by an anchor big enough to hold a *battleship* in place, even if only applied to the "near-coast" parts of the cable, would cost more than redundant cable or even repairing cable (and probably would also require some as yet incomplete scientific breakthroughs. Adamantium, anyone?)
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apparently your imagination is very lacking. if you put the cables underground, then there'd be nothing for the anchor to latch onto. likewise, if you build something similar to an extension cord cover [google.com] over the cables, then they would be similarly protected. it doesn't have to be that strong. some kind of plastic or rubber that is saltwater-resistant would be fine.
no scientific breakthrough needed--just a little a common sense.
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Well, as I said, I'm not an engineer, so I don't know much about the feasibility of burying the cables under the ocean floor... but how would a rubber or plastic "cord runner" help? It's not heavy enough to stop it from being dragged by an anchor until the cable breaks, or likely strong enough to withstand having one dropped on it more than a few times...
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same way that an extension cord cover prevents you from tripping over a cord and ripping it out of the socket. if the cable is lying flat against the ground then there's nothing for the anchor to catch on.
and i highly doubt that there are very many undersea cables that are broken by anchors being dropped directly on top of them. usually when the cables are cut it's due to an anchor being dragged along the seabed by an oil tanker or other large ships. that
The summary has it... (Score:2)
In the summary is enough information to show who has the most to gain from such an interruption and subsequent re-routing. If they are routing traffic through North America, it will be going through the NSA-snooped network. There are moments when I am not proud of America...
Huh? (Score:2, Insightful)
"There are moments when I am not proud of America..."
What does America have to do with you being a paranoid whackjob?
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What part of the illegal NSA wire-tapping program did you miss over the course of this entire year?? And just because it has been exposed does not mean it has stopped! It is STILL RUNNING.
cables and eavesdropping (Score:4, Funny)
I've got sources inside US intel that tell me these are botched attempts by Syrian intelligence to tap these undersea lines.
The chair is against the wall.
John has a long mustache. That is all.
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Any ideas ... (Score:2)
... about who did it?
With OTDRs on-line ready to go on line at ech end of the cable, one should be able to locate the break within hours (if not minutes). Put that together with satellite recon photos and one should be able to track and identify ships in the area to narrow the search down.
Yeah, I know who runs the satellite networks. And it might not be in their best interest to identify one of their own ships. But I'm certain that the Russians would be more than happy to provide the needed data, just to
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... they will find Gilligan's Island and rescue the castaways.
And then whom ever owns the copy right to Gilligan's Island will misread the headline and sue them for using the under sea cable to download episodes of Gilligan's Island
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I bet 10$ that it's Gilligan who cut the cables by accident.
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That's $10 for each of us right?
Gilligan Saved the Cable! (Score:3, Informative)
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I always wondered why didn't they just cut the fucking cable, tie it off, and wait for a repair ship to show up? But then again they where trapped on that island for 15 years and to god damn stupid to build a boat. The professor could pull a fusion reactor out of his ass but couldn't fix a god damn boat engine.
Re:Gilligan Saved the Cable! (Score:5, Funny)
Gilligan didn't cut the cable, ...
He gingerly buried it in Marianne's trench.