Repair Crews Reach Vicinity of Damaged Cables In Mediterranean

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."

Comments

Re:Maybe this time ...

[pipboy9999]

... 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

Dang! I was getting SUCH a good deal

[HawkinsD]

Dang it! I was getting SUCH a good deal from the colocation facility in Yemen.

Wow

[papasui]

Stop pissing off Andrew Ryan.

How do they do it?

[tsa]

How do they repair the cables? Especially with glass fibre I wouldn't know what to do.

Re:How do they do it?

[John Hasler]

> How do they repair the cables?

Superglue and duct tape.

Re:How do they do it?

[TheGratefulNet]

this is for UNDER WATER use.

therefore, its better left to DUCK tape.

(sorry....)

Re:How do they do it?

[Anonymous Coward]

Don't worry, you don't have to do a thing. They already have people who do know what to do.

Re:How do they do it?

[Yvan256]

Red Green to the rescue!

Re:How do they do it?

[pipboy9999]

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?

[Aphoxema]

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.

Re:How do they do it?

[Anonymous Coward]

http://www.laser2000.co.uk/fusion_splicers.php?area=262

Re:How do they do it?

[au3276f8ads7bfsad76s]

Better yet, how do they find where it's broken? I'm assuming you can't just 'ping' the broken end and get a distance measurement...

Re:How do they do it?

[AngelCeleste]

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?

[onkelonkel]

You had it right. OTDR.

Optical Time Domain Reflectometer. You just ping the broken end and get a distance measurement.

Re:How do they do it?

[Octorian]

With a device known as an Optical Time Domain Reflectometer. Supposedly they can not only detect cable length, breaks, but even the location of splices.

Re:How do they do it?

[rickb928]

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?

[davidsyes]

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 the cable dragged out from the opened cofferdam.

Admittedly, the cofferdam might have to be as big as a small submarine (say, 33' in diameter) and include local power supply, air generation, and resting areas for the crew, as well as rapid escape gear. This thing might have to survive extreme depths of around 5,000 feet. But, it won't be rated for combat, shock, and so on, but any 1.5 to 1.9 survival factor (similar to USN submarines) might be good enough since the cofferdam would be towed and ballasted down to the rated working depting.

Possibly even better might be a huge half-pipe that is massively heavy enough to semi-protect workers who are in advanced work suits. But, the nice thing about a mobile clamshell/decomissioned sub-like hull is the crew would be working at depth without suits, pressurized like sub crews, and avoid decompression routines.

Re:How do they do it?

[MBGMorden]

Luckily you can have both in one :)

http://duckproducts.com/products/detail.asp?catid=1&subid=1&plid=3

Re:How do they do it?

[Anonymous Coward]

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.

Re:How do they do it?

[ByOhTek]

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.

Re:How do they do it?

[aphexer]

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 English). But really, they put the fiber in a machine, together with the fiber of the new cable they are putting in between, and they hit a button: "weld". It creates an arc through the point where the fiber needs to be welded together. After the arcing you heat that spot so the atomic structure can repair a little.

Repeat 500 times and put some extra mechanical protection around to protect your welding, and you're done.

There exists equipment that can do multiple fibers at once, so basically the engineer who's doing it just needs to place both ends of the fibers in the machine, hit the button, remove fiber and repeat for a day or 2.

Re:How do they do it?

[AdamHaun]

Actually, you can. You use a device called a Time Domain Reflectometer, 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.

Re:How do they do it?

[joeslugg]

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?)

Re:How do they do it?

[tabrisnet]

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?

[CODiNE]

Surely not! We all know here that ducks float.

Re:How do they do it?

[ColdWetDog]

I knew it! Sharks with Lasers! We don't need any stupid submarines.

Re:How do they do it?

[Anonymous Coward]

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 automatic heating. These machines commonly cost about as much as a nice new car (around $30-50 thousand U.S. dollars, IIRC) and require specialized training and supplies for regular, telephone-pole mounted cables. Undersea cables probably have extra special costs.

In any case, a bundle with hundreds of strands takes days to repair. It can take several hours to splice a broken 36 strand cable.

You can only get so many machines close enough to the broken cable, so the work does not allow for, say, 50 splicers to all work on it at once.

Of course, I'm glossing over all the work it takes to pull a cable off the sea floor, get it on a ship, and then put it back. Someone else can gather karma for that info ;)

Re:How do they do it?

[lucifuge31337]

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.

Re:How do they do it?

[AliasMarlowe]

Surely not! We all know here that ducks float.

Only if they weigh the same as a witch!

Re:How do they do it?

[SETY]

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.

Re:How do they do it?

[IonOtter]

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 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 you'll be back.

The Zeus would drive a Tibetan Hermit insane.

Re:How do they do it?

[Anomalyst]

If you nudged it, the connection went down!

So, after a nudge, nudge you get a wink, wink? Does that make the cable a goer?

Re:Maybe this time ...

[internetcommie]

In the age of the intarwebs undersea piracy has replaced piracy on the high seas!

Slack

[terraformer]

There has to be a lot of slack for them to be able bring up both ends and not require massive amounts of force or cause stress on the ends. I wonder if they lay the cable not straight but in shallow s-turns back and forth to introduce slack into the system.

Re: Slack

[Civil_Disobedient]

There was a terrific article written for Wired by Neal Stephenson (yes, that Neal Stephenson!) called Mother Earth Mother Board 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:

The basic problem of slack is akin to a famous question underlying the mathematical field of fractals: How long is the coastline of Great Britain? If I take a wall map of the isle and measure it with a ruler and multiply by the map's scale, I'll get one figure. If I do the same thing using a set of large-scale ordnance survey maps, I'll get a much higher figure because those maps will show zigs and zags in the coastline that are polished to straight lines on the wall map. But if I went all the way around the coast with a tape measure, I'd pick up even smaller variations and get an even larger number. If I did it with calipers, the number would be larger still. This process can be repeated more or less indefinitely, and so it is impossible to answer the original question straightforwardly. The length of the coastline of Great Britain must be defined in terms of fractal geometry.

A cross-section of the seafloor has the same property. The route between the landing station at Songkhla, Thailand, and the one at Lan Tao Island, Hong Kong, might have a certain length when measured on a map, say 2,500 kilometers. But if you attach a 2,500-kilometer cable to Songkhla and, wearing a diving suit, begin manually unrolling it across the seafloor, you will run out of cable before you reach the public beach at Tong Fuk. The reason is that the cable follows the bumpy topography of the seafloor, which ends up being a longer distance than it would be if the seafloor were mirror-flat.

Over long (intercontinental) distances, the difference averages out to about 1 percent, so you might need a 2,525-kilometer cable to go from Songkhla to Lan Tao. The extra 1 percent is slack, in the sense that if you grabbed the ends and pulled the cable infinitely tight (bar tight, as they say in the business), it would theoretically straighten out and you would have an extra 25 kilometers. This slack is ideally molded into the contour of the seafloor as tightly as a shadow, running straight and true along the surveyed course. As little slack as possible is employed, partly because cable costs a lot of money (for the FLAG cable, $16,000 to $28,000 per kilometer, depending on the amount of armoring) and partly because loose coils are just asking for trouble from trawlers and other hazards. In fact, there is so little slack (in the layperson's sense of the word) in a well-laid cable that it cannot be grappled and hauled to the surface without snapping it.

This raises two questions, one simple and one nauseatingly difficult and complex. First, how does one repair a cable if it's too tight to haul up?

The answer is that it must first be pulled slightly off the seafloor by a detrenching grapnel, which is a device, meant to be towed behind a ship, that rolls across the bottom of the ocean on two fat tractor tires. Centered between those tires is a stout, wicked-looking, C-shaped hook, curving forward at the bottom like a stinger. It carves its way through the muck and eventually gets under the cable and lifts it up and holds it steady just above the seafloor. At this point its tow rope is released and buoyed off.

The ship now deploys another towed device called a cutter, which, seen from above, is shaped like a manta ray. On the top and bottom surfaces it carries V-shaped blades. As the ship makes another pass over the detrenching grapnel, one of these blades catches the cable and severs it.

It is now possible to get hold of the cut ends, using other grapnels. A cable repair ship carries many d

Conspiracy Theory

[Anonymous Coward]

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.

Re:Satellites FTW?

[karmatic]

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.

Gilligan Saved the Cable!

[camperdave]

Gilligan didn't cut the cable, the Professor did. He made a saw out of Mrs Howell's diamonds to try to cut through the outer sheath of the cable. When that didn't work, he rigged a blow torch to burn/melt his way through to the wires. All Gilligan did was cover up the hole with tree sap when the storm hit again. He *SAVED* the cable.

Re:Gilligan Saved the Cable!

[Wansu]

  Gilligan didn't cut the cable, ...

He gingerly buried it in Marianne's trench.

Re:Satellites FTW?

[hardburn]

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.

cables and eavesdropping

[BigHungryJoe]

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.

Standard fare on good network testers

[Sycraft-fu]

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.

Huh?

[GuloGulo]

"There are moments when I am not proud of America..."

What does America have to do with you being a paranoid whackjob?