
The secret world of microwave networks - kintamanimatt
http://arstechnica.com/information-technology/2016/11/private-microwave-networks-financial-hft/
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greenyoda
Previous discussion, a couple of days ago:
[https://news.ycombinator.com/item?id=12862789](https://news.ycombinator.com/item?id=12862789)

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candiodari
> Stretching between London and Frankfurt, there is a private, mysterious
> network that is twice as fast as the normal Internet

In latency, perhaps. Microwave networks are famous for the minimal bandwidth
they provide though.

It's also not even a case of using a shorter route. Speed of light in fiber =~
2/3c, speed of light in "free space" (atmosphere) =~ 99%. On the exact same
route, microwaves will be faster, with one tiny caveat. Light can be
regenerated through a site (retransmitted without any delay, ie. pure optical
regen), microwaves cannot. So in reality the situation is:

0-50 km: fiber wins, hands down (with one exception: cell antennas. Since you
already have power + antenna approval, it can be cheaper to just microwave the
signal to a central point versus get a fiber connection) 50-500 km: microwave
wins, but wouldn't win on the same route (fiber routes within cities have to
take the long and winding road due to approvals and obstacles) 500km+: due to
the fact that it isn't known how to keep microwave dishes stable on the ocean
that is near-inevitable on these distances, fiber wins

Some time in the future free space optical transmissions over either LEO
satellites or solar-powered planes will win out over microwave terrestrial
transmissions. Free space optics also have the massive advantage that they do
not require approvals, either for the planes (vs very very tall masts for
microwave, which definitely need approval and often face local opposition),
nor do they require approval for the transmission (microwave transmissions at
the power levels required for these distances require approval). Since free
space optical transmissions have far greater bandwidth, I'm hopeful that we'll
be seeing internet latency reduce as well. Also, while satellites aren't
cheap, one satellite has about the same price as 50-100 km undersea fiber.
Therefore a 500 satellite constellation is cheaper than laying a single cable
from London to New York. Of course, fiber will remain the bandwidth king for
the time being.

