3RD IAIT
NERVOUS SYSTEM OF THE EARTH
You think the internet lives in the cloud. It lies at the bottom of the ocean.
Bandwidth Architecture
Modern submarine cables transmit data at up to 340 Tbps. Light pulses travel through hair-thin glass fibers at 200,000 km/s.
Fighting Signal Decay
Optical repeaters sit every 80 km on the ocean floor to boost fading light, powered by 10,000V DC sent through the cable's core from shore.
Sharks vs. The Internet
Sharks bite cables sometimes. They are attracted to the electromagnetic fields. The vulnerable sections now get steel and Kevlar wrapping.
The Cable-Laying Giants
Specialized cable ships hold up to 8,000 km of cable. They move at 6 knots while laying cable with millimeter precision using GPS and sonar arrays.
Chokepoints & Severance
A ship's dragged anchor or a deliberate submarine attack can silence a country. In 2022, Tonga was completely isolated for five weeks after a volcanic eruption severed its only link.
Landing Stations
The cables emerge from the sea into hyper-secure concrete bunkers on beaches worldwide, where 10,000V power is injected and light is routed to terrestrial data centers.
Repair Expeditions
When a break occurs, ROVs (Remotely Operated Vehicles) dive thousands of meters to retrieve the ends, haul them to the surface ship, and splice glass strands thinner than a hair.
The Private Backbone
Historically funded by telecom consortiums, today over 60% of new transoceanic capacity is being built exclusively by Google, Meta, Amazon, and Microsoft.
THE “CLOUD” IS A LIE.
Owned by Giants
Five companies own or co-own the cables that carry over 95% of global internet traffic: Google, Meta, Amazon, Microsoft, and a few telecoms. The internet is private infrastructure, not public.
Geopolitically Volatile
A volcanic eruption severed Tonga's only cable in 2022. The country went offline for five weeks. Submarines could do the same thing deliberately during a conflict. NATO now treats cable attacks as a national security threat.
Physically Fragile
Cables near shore are buried. In deep water they just sit on the ocean floor. A dragging ship anchor can cut off a region's internet in seconds. Over 100 cables get repaired every year.
THE NUMBERS
What it takes to keep the world connected
Bandwidth Explosion
Submarine cable capacity has grown 1,000x in 25 years
Who Owns the Internet
Over 60% of new cable capacity is built by just five tech companies
THE BANGLADESH CONNECTION
How those cables connect to Bangladesh and what it means for people here
Three Cables, One Coastline
Bangladesh connects to the global internet through three submarine cable systems: SEA-ME-WE 4, SEA-ME-WE 5, and the upcoming SEA-ME-WE 6. They come ashore at Cox's Bazar and Kuakata.
From Isolated to Connected
Bangladesh got its first submarine cable in 2006 with SEA-ME-WE 4. Before that it relied on satellite links. International bandwidth has gone from 20 Gbps to more than 2,200 Gbps since then.
Digital Bangladesh
Every Bkash payment, every video call, every export order processed online goes through these glass fibers on the ocean floor. They are not optional infrastructure.
LIVE CABLE MAP
Every line on this globe is a real submarine cable route
Route data sourced from TeleGeography SubmarineCableMap & ITU Global ICT Statistics
It runs 24/7. You've never seen it. Now you know.
The next time you send a message from Dhaka to New York it travels to a cable landing station, gets converted to light, and shoots through a glass fiber across 15,000 km of ocean in 60 milliseconds.