But how does it work? Have you ever wondered how an image of a cat gets to your London computer from an Oregon server? We are not just talking about the wonders of TCP / IP or the ubiquitous Wi-Fi hotspots, although all of these are important. No, we are talking about a large infrastructure: huge submarine cables, vast data centers with all their redundancy of power systems and gigantic, labyrinthine networks that connect billions of people directly to the Internet.
Perhaps more importantly, as we rely more and more on ubiquitous Internet connectivity, the number of connected devices increases, and our thirst for traffic knows no bounds. How do we make the internet work? How do Verizon and Virgin (the largest Internet service providers in the US - approx. New) manage to constantly transfer one hundred million bytes of data home every second, non-stop, every day?
Well, after reading the next seven thousand words, you will know about it.
British Telecom (BT) can attract customers with the promise of fiber to every home (FTTH) for higher speeds, and Virgin Media has a good quality of service - up to 200 Mbps for individuals thanks to its hybrid coaxial fiber network ( GVC)… But, as the name suggests, the World Wide Web is truly a global network. Internet insurance exceeds the power of a single provider on our island or, indeed, anywhere in the world.
First, we will take a look at one of the most unusual and interesting cables that carry data and how it reaches the British coast. We are not talking about any common thread between the data centers on the ground a hundred miles away, but about a contact station in a mysterious place on the west coast of England, where, after a journey of 6500 kilometers from New Jersey American, the Atlantic Tata submarine cable ends.
An American connection is essential for any major international communications company, and the Tata Global Network (TGN) is the only single-owner fiber network on the planet. It is about 700 thousand kilometers of submarine and terrestrial cables with over 400 communications nodes worldwide.
However, Dad is willing to share. Not only can the director's children play Call of Duty without delay, but a select group can watch Game of Thrones online without delay. The Tata Tier 1 network accounts for 24% of the world's internet traffic every second, so the chance to meet TGN-A (Atlantic), TGN-WER (Western Europe) and their cable friends is not to be missed.
The station itself - a fairly classic data center in appearance, gray and indescribable - may generally seem like a place where, for example, cabbage is grown. But inside everything is different: to move around the building you need RFID cards, to enter the data center - give the impression, but first - a cup of tea and a conversation in a conference room. This is not your usual data center, and some things need to be explained. In particular, submarine cable systems require a lot of energy, which is provided by many waiting units.
Protected submarine cables: Benefits of Dark Fiber
Carl Osborne, Tata's Vice President of World Networks, joined us on tour to share our thoughts. Before Dad, Osborne worked on the ship himself, laying the cable and overseeing the process. He showed us samples of submarine cables, demonstrating how their design changes with depth. The closer you are to the surface, the more insulation you need to withstand potential transport damage. The ditches are dug in shallow water where the cables are laid. However, at greater depths, as in the Western European Basin with a depth of almost five and a half kilometers, no protection is required - commercial transport does not threaten the cables from the bottom.
At this depth, the cable diameter is only 17 mm, it is like a felt pen in a thick polyethylene insulating sheath. The copper conductor is surrounded by a lot of steel wires that protect the optical fiber core, which is embedded in a steel tube with a diameter of less than three millimeters in soft thixotropic jelly. The shielded cables are the same inside, but in addition they are covered with one or more layers of galvanized steel wire wrapped around the entire cable.
Without a copper conductor, there would be no submarine cable. Fiber optic technology is fast and can carry almost unlimited amounts of data, but fiber cannot run long distances without a little help. To improve the transmission of light along the entire length of a fiber optic cable, repeaters are needed - in fact, signal amplifiers. On land, this is easily done with local electricity, but at the bottom of the ocean, the amplifiers draw direct current from the copper conductor of the cable. Where does this current come from? From the stations at both ends of the cable.
Although consumers do not know this, the TGN-A is actually two cables that cross the ocean in different ways. If one is damaged, the other will ensure continuity of communication. The TGN-A alternative lands 110 kilometers (and three ground amplifiers) from the main and takes its energy from there. One of these transatlantic cables has 148 amplifiers, while the other, longer, has 149.
Station leaders are trying to avoid publicity, so I'll call our station guide John. John explains how the system works:
"To power the cable, there is a positive voltage at our end, but in New Jersey it is negative. We try to maintain the current: the voltage can easily hit the resistance of the cable. A voltage of about 9 thousand volts is divided between the two ends. This is called bipolar feeding. So at about 4,500 volts at each end. Under normal circumstances, we could keep the entire cable working without any help from the United States. "
Needless to say, the amplifiers are built to last 25 years without interruption, as no one will send divers down to change contact. But looking at the test of the cable itself, inside which there are only eight optical fibers, it is impossible not to think that, with all these efforts, there must be something more.
"Everything is limited by the size of the amplifiers. Eight fiber pairs require amplifiers twice the size, ”explains John. And the more amplifiers there are, the more energy is needed.
At the station, the eight wires that make up TGN-A form four pairs, each containing a receiving fiber and a transmitting fiber. Each wire is painted in a different color, so that in the event of a breakdown and the need for repairs at sea, technicians can understand how to reassemble everything in its original state. Likewise, onshore workers can figure out what to enter when connected to a submarine line terminal (SLTE).
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