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Aboard an Alcatel-Lucent undersea cable ship (photos)

The telecommunications infrastructure company gives ZDNet UK a tour of its cable gear factory and the ship Ile de Batz, offering a look at a vital part of the global Internet that's normally hidden by miles of water.

1 of 13 David Meyer/ZDNet UK

Ile de Batz

The Ile de Batz is one of three dedicated ships that Alcatel-Lucent uses to lay the submarine fiber-optic cables that carry broadband connectivity across the oceans. The ship is usually based in Calais, France, but made a stop recently in Greenwich, England, to pick up components from Alcatel-Lucent's factory. The telecommunications infrastructure company invited ZDNet UK to see the factory and the ship, and have a look at a vital part of the global Internet that's normally hidden by miles of water. The Ile de Batz usually spends between 30 and 40 days at sea on each voyage. It can lay up to 200 kilometers (120 miles) of cable per day, in normal conditions, to a depth of about 8km. That cable and its components are expected to have a lifespan of about 25 years.

2 of 13 David Meyer/ZDNet UK

Philippe Dumont

Philippe Dumont is in charge of Alcatel-Lucent's submarine network business. The market for such deployments, he said, has remained "quite stable" over the last couple of recessionary years, which "came as quite a surprise" to Alcatel-Lucent.

Dumont said the biggest cabling project in the world right now is Africa, but the connectivity being deployed there will be quite different from what people in the U.K. are used to. "Access to the Internet in Africa is mostly based on mobile," he said. "You will not see DSL, but you will see mobile broadband through smartphones and USB dongles."

The biggest part of the traffic in such a deployment will come from consumers, followed by enterprise customers such as banks that have been somewhat cut off from the world's Internet infrastructure until now.

A big cable deployment can be worth around half a billion dollars, so telecom operators tend to invest in such projects through consortia, rather than on their own. According to Dumont, the competition between consortium members will drive down prices for end users.

3 of 13 David Meyer/ZDNet UK

Submarine cable

Here, a member of the ship's crew shows off the various thicknesses of cable that are deployed from the Ile de Batz.

The different sizes are used at different depths, although surprisingly the larger diameters are used closer to the surface. The top example in this picture is the lightweight cable that Alcatel-Lucent uses in very deep oceans, where ships' anchors pose no threat. The shallower the waters, the more heavily-armored the cable needs to be, as depicted in this progression of thickness.

If cut, the cable can be repaired--Alcatel-Lucent has more ships on standby around the world for this purpose--but each reconnection degrades the system gain of the cable. The system is designed with enough headroom to tolerate a certain number of repairs.

4 of 13 David Meyer/ZDNet UK

Cable-splicing machine

This is the cable-splicing machine used on board the Ile de Batz--one of the most delicate and precise pieces of equipment on a ship laden with very heavyweight gear.
5 of 13 David Meyer/ZDNet UK

Molding machine

This machine molds protective layers on to the cable. The ship acts as much as a factory and repair shop as a straightforward spooler-out of cable; each leg of a cable requires a lot of individual customization.
6 of 13 David Meyer/ZDNet UK

Cable tank

Here is one of the Ile de Batz's two main cable tanks, with a small amount of spare 17mm cable included for the benefit of those touring the ship.

Each of the ship's two cable tanks can hold up to 5,500km, or 3,000 tons, of fiber-optic cable. There are also two spare tanks, each with a 250-ton capacity.

7 of 13 David Meyer/ZDNet UK

Linear cable engine

This is the linear cable engine used to feed cable from the tanks to the rear of the Ile de Batz, from where it descends to the briny depths.
8 of 13 David Meyer/ZDNet UK

The plow

This massive and surreal device is the Ile de Batz's plow, which is used to bury cable. The cable can be buried up to 3m under the sea bed, which happens in waters up to 1.5km deep. This is the limit of what those in the industry consider to be "shallow" waters--areas where fishing takes place, and cables need to be especially well-protected.
9 of 13 David Meyer/ZDNet UK

Control systems

The Ile de Batz has all of the normal navigation and engine systems of any large vessel, but with the addition of specialist controls shown here. These are separate from those used for the main navigation and cable-laying functions of the Ile de Batz, and use precision sensors and computers to calculate the strength of the sea and the wind to exactly control the ship's movement during cable deployment.
10 of 13 David Meyer/ZDNet UK

Greenwich factory

This is Alcatel-Lucent's Greenwich factory--the same site where part of the first transatlantic cable was built in the mid-19th century. These days, the factory is used to build three particular pieces of cable kit: repeaters, branching units, and power feed equipment.
11 of 13 David Meyer/ZDNet UK


This is one of Alcatel-Lucent's repeaters, which are used to amplify the signal at various points along the cable. This repeater, a model from two years ago, has a throughput of around 1.5 terabits per second.
12 of 13 David Meyer/ZDNet UK

Branching unit

Alcatel-Lucent also makes branching units at its Greenwich facility. This is the component that would be used to split off connectivity to a site that the cable passes by--for example, to Congo on the West Africa Cable System (WACS), which runs from the U.K. to South Africa, that Alcatel-Lucent is building.
13 of 13 David Meyer/ZDNet UK

Power feed equipment

This power feed equipment, produced at Alcatel-Lucent's Greenwich facility, is destined to be deployed where the WACS line comes ashore in Congo. This is the kit that powers the repeaters along a submarine cable.

Alcatel-Lucent's Dumont said he expects the big African deployment to wind down around 2012 for the cable part, after which a second wave of transmission backhaul will be rolled out.

"We think Asia will be next--there is [capacity] but not so many connection points," Dumont said. "China has a lot of needs, as do small countries like Vietnam. The west of Australia also has very little connectivity."

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