The Physical Internet

Over three billion people use the Internet on a regular basis, with 46,000 gigabytes of data pulsing through cables each and every second. While the Internet has been described as a network, a culture, or even a cloud of information - these abstract concepts hide a simple and very physical reality. Behind the romance of instantaneous communication and free information, the Internet relies on a bunch of cables and data exchanges that criss-cross the globe.

Most people don't think about the physical nature of the Internet - in fact - the existence of a global network seems to transcend the concept of geography. In reality, however, the emails that you write and websites that you visit rely on detailed and highly organised physical infrastructure. Data servers and fibre optic cables form the basis of this structure, with servers acting as nodes and cables acting as information highways between global hubs. While the Internet is now available in practically every corner of the world, the physical structure of the Internet is very much based in the West.

Starting out on the American West Coast in 1969, the original ARPANET expanded to New York and eventually to the United Kingdom in 1973. ARPANET officially became the Internet in 1984 when it was reorganised as a decentralised "network of networks." However, despite this democratic vision, there are still only a few major exchanges that form the backbone of the modern Internet. For example, only six exchanges have an average throughput of over 1,000 gigabytes per second, with the most significant servers found in North America and Europe.

Despite its massive size, even the Internet can't escape geography, with many data centres located in geographically significant locations rather than world centres. If you're a user of Google, Facebook, Yahoo, or Microsoft, your personal data is probably stored at a private data centre in a stable region with access to inexpensive power. While smaller web companies store their servers in large data centres managed by third parties, larger companies increasingly have their own dedicated data centres where hundreds of thousands of servers are located. Google and Microsoft have six data centres each in the United States, with additional servers popping up across Europe and Asia.

If data centres are the capital cities of the Internet, then fibre optical cables are the highways that run between them. A single piece of fibre cable can transmit as much as 100 billion bits per second, which is about ten thousand times faster than a typical home broadband connection. Because a single cable can contain hundreds of fibres, it only takes one cable to provide enough capacity for millions of users. Super submarine cables link continents across the ocean floor, with smaller cables linking countries and cities and mobile networks taking more of the burden every day.

The world's major information super-highways run across America and between the United States and Europe, with other significant lines running into Asia and down the coast of Africa. The North Atlantic Ocean between America and Europe is the busiest place for submarine cables, especially between New York and London. Other major fibre- ways run between the East Coast of America and Japan, around the South China Sea, and across the Mediterranean. Next time you receive an email or check your Facebook messages, take a moment to remember, each piece of data relies on real junctions and real cables that stretch and pulse across the globe.

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