The majority of people around the world, including George Clooney in “Gravity” believe that the Internet’s connectivity is provided by satellite communications. Not so, I hear the likes of the content providers such as Amazon, Facebook, Google, Microsoft, as well as all the telecommunications companies say. For the moment, they are correct in that about 99.5% of our international data and voice connectivity is provided over submarine fibre cables which cross-cross the world.  The global submarine network is comprised of an estimated 213 independent fibre cable systems totalling c 550,000 miles (900,000 km) of fibre.  Each year sees another 20-30 submarine cables systems being built to augment or replace the existing cables, provide additional diversity and connectivity enabling more capacity for the global Internet.

However, “the times they are a changing” and a number of factors, both political and technological are becoming evident which could become a fundamental game changer for the current submarine fibre cable (and terrestrial fibre backhaul) based global Internet.

Just before Christmas, two influential security papers were released: one in the UK and one in Taiwan which identified that the global submarine cable systems were vulnerable and could be taken down.  This is nothing new and over a century ago in World War One, the first act of Winston Churchill, then the First Sea Lord in the British Admiralty was to order the Royal Navy to severe the German telegraphic cables linking their colonies to Germany. That resulted in Germany using long range HF radio which could then be intercepted and vital messages decrypted.  

Now over 100 years later, UK's most senior military officer has warned of a new threat posed by Russia to communications and internet cables that run under the sea. Air Chief Marshal Sir Stuart Peach, Britain Chief of Defence Staff, said Britain and NATO needed to prioritise protecting the lines of communication. He stated it would "immediately and potentially catastrophically" hit the economy if they were cut or disrupted. Western Defence and intelligence chiefs see not just increased Russian submarine activity in the Northern waters, but its willingness to use unconventional asymmetric warfare.

Sir Stuart said: "There is a new risk to our way of life, which is the vulnerability of the cables that criss-cross the sea-beds. Can you imagine a scenario where those cables are cut or disrupted, which would immediately and potentially catastrophically affect both our economy and other ways of living."

According to the Policy Exchange report - published in December 2017 many cable systems are potentially at risk.

"Undersea cables are the indispensable infrastructure of our time, essential to our modern life and digital economy, yet they are inadequately protected and highly vulnerable to attack at sea and on land, from both hostile states and terrorists," the report concluded.

Conservative MP Rishi Sunak, author of the report, warned a successful attack on the UK's network of undersea communications cables could deal a "crippling blow" to the country's security and economy.

In Asia, China also sees submarine cable networks as an essential element of its “One Belt, One Road” initiative. Undersea cables will ensure that Beijing is well placed to influence communications and media as part of its global strategy and the three main Chinese telecommunication operators are investing heavily in new submarine cable builds to Asia, the US and Europe from mainland China.

With the build-up of Chinese forces in the South China Sea and potential flash-points in the region with the US, the Philippines and Vietnam, cable operators are looking to diversify new submarine cable builds away from the South China Seas to reduce risk and provide additional diversity.

We are also seeing certain submarine cable “choke-points” such as Egypt which all the present Europe–Asia submarine cables currently transit and natural choke-points in Asia, such as the Luzon Straits which are prone to sea-quakes. Natural disasters or political upheaval can and has had a serious impact on global communications and while this primarily impacts and slows down the Internet, outages are having an adverse impact on trade and financial dealings as systems become more automated.

As a result, planners are looking for diversification using “meshed” networks to provide resilience and high availability, but this all comes at a cost and end to end connectivity is only as good as the weakest link in the chain.

One of the challenges in building submarine cable systems and the supporting terrestrial backhaul is that it is primarily point to point connectivity and requires fibre to be laid. Many locations, especially in the interiors of Africa, Asia and the Middle East do not have this fibre overlay, although major build programmes are underway to support mobile 4G and in the future 5G, as well as superfast broadband.  For those areas without fibre connectivity, satellite can offer a solution, but the current technology is confined to radio frequency spectrum (RF) with bandwidths of up to 1 Gbps which is limited compared to the 10-200 Gbps wavelengths available on fibre.  Off-shore facilities such as oil and gas rigs, as well as maritime and naval shipping are also largely dependent on satellite communications.  

Satellite communications uses the radio frequency spectrum and the satellites themselves are normally in geostationary orbits, which causes latency issues given the distance involved from the earth’s surface. Satellite operators have built new constellations which are closer in either medium earth orbit (MEO) or even low earth orbits (LEO) to improve latency, but the higher bandwidth required is only achievable by using lasers.     

We are now seeing technological advances in Free Space Optics (FSO) which may help provide a three dimensional solution to the challenge for the next evolution of the global Internet.  Free-space optical communication is a technology that uses light propagating in free space to transmit data for telecommunications or computer networking. "Free space" in this instance means air or a vacuum (space). This contrasts with optical fibre as used in terrestrial and submarine cables. Light in free space also travels up to 30% faster than light in a fibre so careful planning is required to see which is more effective taking into account the additional distance due to the up and down satellite links.  This gives a break-even point of around 8,000km between submarine/terrestrial versus satellite.

Space Communications

The major advantages of laser communication in space have the various space agencies racing to develop a stable space communication platform, with many significant demonstrations and achievements.  In deep space, laser communications is now routine for space missions but the constraint comes when NASA and the other agencies want to transmit high volume bandwidth data which they have collated from space missions down to earth. Here they have to use conventional RF transmissions and the simplest analogy is trying to empty a reservoir using a tap.  

The first gigabit laser-based communication was achieved by the European Space Agency in November 2014 and is called the European Data Relay System (EDRS) and is now fully operational. A two-way distance record for communication was set by the Mercury laser altimeter instrument aboard the MESSENGER spacecraft, and was able to communicate across a distance of 15 million miles (24 million km), as the craft neared Earth on a fly-by in May 2005. Laser communications in deep space will be further tested on the PSYCHE mission to the main-belt asteroid 16 Psyche, planned to launch in 2022. The system is called Deep Space Optical Communications, and is expected to increase spacecraft communications performance and efficiency by 10 to 100 times over conventional means.

NASA's OPALS project achieved a breakthrough in space-to-ground communication in December 2014, uploading 175 megabytes in 3.5 seconds. Their system was also able to re-acquire tracking after the signal was lost due to cloud cover.

These advances have helped pave the way for a new ground and space global network which can deliver bandwidths of 10-100Gbps and upwards required to service the global Internet.  The main challenge is that the lasers and the transmitted light are affected by weather and clouds, fog and rain which all deteriorate the laser signal and as a result any satellite network has to take account of the effects of the troposphere.  Ideally, the satellite ground stations should be in locations which have clear blue skies to provide 100% availability.  The reality is that cloud free line of sight between the satellite and the ground station will vary depending on the location, time of year and weather.   

Quantum computing and the Quantum Internet

As computing power increases, we are also seeing rapid advances in computing power with quantum computing promising to be the most exciting step change in computing power and the ability to solve complex problems.  One of the main challenges for quantum computing is achieving low latency connections between computers and free space optics offers advantages compared to conventional fibre optic communications as it is around 30% faster.  

"Because there's no air between the satellites, there's nothing to degrade the signal," says Dr Jamie Vicary, a senior research fellow at Oxford University's department of computer science and a member of the Networked Quantum Information Technologies Hub (NQIT).

"If we want to have a really global-scale quantum Internet, it looks like a space-based solution is the only way that will work, but it's the most expensive."

Rupert Ursin, senior group leader at the Austrian Academy of Sciences' Institute for Quantum Optics and Quantum Information believes the quantum internet will need land-based and space-based networks to operate in parallel.

"In the cities, we need a fibre network, but long haul connections will be covered by satellite links," he explains. 

Global Network Vision

As one potential solution to the challenges raised in this article, Laser Light Communications intends to deploy an All-Optical Global Communications Network called HALO™.  Laser Light’s proposed satellite backbone will interconnect over 100 customer Points of Presence (PoP) or ground nodes clustered within 20+ SD-WANs around the world. The PoPs would be connected in an SD-WAN “hub and spoke” arrangement with regional terrestrial and subsea fibre connectivity to provide a fully-meshed network. This would enable the cloud free line of sight between the satellite and ground stations to be taken into account and traffic to be routed via the appropriate route (both satellite and fibre cable) to provide the high availability and lowest latency.  

The capacity of the planned HALO constellation (initially 8 building to 12 Medium Earth Orbit satellites at 10,000km) is in excess of 33Tbps.  The full network would be comprised of 48 Satellite-Satellite 200Gbps optical crosslinks and 72 Satellite-Ground 100Gbps optical bi-directional links.  Customers such as global enterprises, private network providers, data centres, media companies, financial institutions, carriers, and government entities would be connected via the space segment, as well as conventional regional fibre, as each ground node can mutually support other ground nodes as diverse satellite locations.

The traffic routing algorithms would take account of adverse weather and route traffic accordingly to the nearest available node and use the “hub and spoke“ connectivity to deliver traffic. Although still in the funding stage, this initiative is attracting interest and offers a three dimensional connectivity solution for the Global Internet. The solution also addresses security concerns and provides bandwidth on demand services.

So George Clooney could be right and in the 2020s we may see a significant shift of Internet traffic from submarine cables to space.