349. Submarine Cables

Submarine   Cables

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The internet’s largest and most important — and yet unsung — champions are the privately-owned submarine cables that orbit the Earth.
Terra firma links between cities and cables that run alongside roads and into houses and officers are certainly impressive — and without them we wouldn’t have an internet! — but sinking a cable into the Pacific, Atlantic, Indian, and even Arctic Oceans requires a billion-dollar logistical feat that requires months or even years to enact.
Across these cables, which span distances of up to 13,000 km (8,000 miles) and have total lengths over 21,000 km (13,000 miles), terabits of information squirt from one side of the planet to another.
To get from London to Tokyo, your packets can traverse Europe, the Mediterranean, the Red Sea, the Arabian Sea, the Indian Ocean, and finally the South China Sea — or they can hop across the Atlantic, the entirety of continental North America, and then long haul over the Pacific.
These cables are just three inches thick, carry just a few optic fibers, and have total capacities of between 40Gbps and 10Tbps, and latencies that are close to the speed of light and just a few milliseconds in duration.
These cables shouldn’t run out of capacity any time soon, too: we’re already at the stage where we can send 40Gbps over a single fiber, and graphene optical switches should expand the total capacity of submarine cables (and the terminating routers) into the petabit- and exabit-per-second range.
As far as laying a submarine cable, specialized cable-laying ships must be used — and again, when a cable is broken (usually by a trawler, but sometimes a whale!), another special ship must be used. This generally means that laying a cable is logistically challenging and very expensive — and when a cable breaks, it sometimes isn’t possible to fix it immediately if a cable-fixing ship isn’t nearby (and for this reason, most submarine cables use a ring topology in case one stretch is broken).
It’s also amazing to consider that the first trans-Atlantic cables were laid in the 1860s, and trans-Pacific cables followed in the early 1900s. These cables were incredibly low-bandwidth — repeaters didn’t exist yet, so the only way of getting a signal across the pond was by upping the voltage and creating a very noisy link — but by the early 1900s, the British Empire had already connected up most of the continents (see below). It’s also worth noting that the only continent that isn’t wired into the internet is Antarctica; the temperature of the Antarctic Ocean is too low, and the movement of the ice shelf by up to 10 meters per year is tricky to overcome.
Finally, we would be remiss to ignore geostationary, orbital communications satellites. While satellite data links can be in the gigabit range, the high latency of bouncing a signal through a point that is rather far away (35,000 km, 22,000 miles) makes them unsuitable for many consumer internet services. This same latency will pose some big problems when we start colonizing other planets and need to create an interplanetary (or intergalactic) internet, or galnet for short.

Damage affects internet services

MULTAN, Mar 27 - One of the international submarine cable’s (SMW4) has experienced fault in sea waters near Alexandria, Egypt which has impacted internet services in the Far East, Middle East, Pakistan, India and North Africa.
The total length of the SEA-ME-WE 4 (SMW4) submarine cable system is approximately 20,000 km which consists of the main backbone across the Eastern and Western worlds and links 14 countries with 16 landing stations across Europe, Middle East and Asia plus the extension links in various countries.
The international consortium of operators in the region that manages the submarine cable system is proceeding to deploy repair services to restore services at the earliest, said a press release issued here by PTCL on Wednesday.
Meanwhile, PTCL has already undertaken necessary actions to minimize the impact on the services to customers in Pakistan, by making alternate arrangements for internet capacity.
This has been made possible because of PTCL multiple submarine cable systems in Pakistan, added the release.
Customers may experience slow browsing during peak hours and PTCL sincerely regrets this temporary inconvenience caused to valued customers, under the prevalent circumstances, concluded the release.

customer is better because we have no other ISP)