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Network Latencies and Speed of Light

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Re: Network Latencies and Speed of Light

#31

Post by sgt101 »

ericjang wrote: post #9

Money is no object to HFT firms when it comes to reducing latency. A recent technique involves laying optic fiber cables with hollow interiors, so that the internal refraction of light spends more time in a vacuum and less time slowed down by the pesky glass medium.

Which is why the regulators really need to get sharper with them vs. what they are doing to the economy. They are front running, destroying value and spending the money on a whole load of tat - a massive case of misallocation of capital. They need to be shuttered.

Re: Network Latencies and Speed of Light

#33

Post by dfee »

js2 wrote: post #7

Obligatory link to "The case of the 500-mile email": https://www.ibiblio.org/harris/500milemail.html

My favorite part: “I diffed it against the sendmail.cf in my home directory. It hadn't been altered--it was a sendmail.cf I had written. And I was fairly certain I hadn't enabled the "FAIL_MAIL_OVER_500_MILES" option.”

Re: Network Latencies and Speed of Light

#34

Post by Retric »

mkj wrote: post #30
bostik wrote: post #27

Earlier quoted context omitted.

> Why aren't HFT firms using short wave radio (DXing)? They are. See mshook's response, with nice reference links downthread: https://news.ycombinator.com/item?id=16196339

Those are microwave which basically need line of sight? I was thinking of lower frequencies which can sometimes go hundreds of kilometers without repeaters.

You want your severs as close as possible to an exchange. Even 2 miles is a noticeable increase in latency.

Re: Network Latencies and Speed of Light

#35

Post by Simon_says »

ec109685 wrote: post #28
bawana wrote: post #23

going through the earth is a shorter distance but unfortunately light speed is slower that way

Why is light slower that way?

I'm not sure if this is what he's referring to, but light (and the passage of time) is slower in a gravity well. A geodesic in spacetime will minimize the time it takes for light to travel between two points. In the case of going through the Earth, the geodesic will be only slightly deflected from what you would consider the straight-line path through a sphere in a flat spacetime.

Re: Network Latencies and Speed of Light

#37

Post by paulddraper »

sgt101 wrote: post #31
ericjang wrote: post #9

Money is no object to HFT firms when it comes to reducing latency. A recent technique involves laying optic fiber cables with hollow interiors, so that the internal refraction of light spends more time in a vacuum and less time slowed down by the pesky glass medium.

Which is why the regulators really need to get sharper with them vs. what they are doing to the economy. They are front running, destroying value and spending the money on a whole load of tat - a massive case of misallocation of capital. They need to be shuttered.

HFT, or Bitcoin?

Re: Network Latencies and Speed of Light

#38

Post by jlgaddis »

mkj wrote: post #30
bostik wrote: post #27

Earlier quoted context omitted.

> Why aren't HFT firms using short wave radio (DXing)? They are. See mshook's response, with nice reference links downthread: https://news.ycombinator.com/item?id=16196339

Those are microwave which basically need line of sight? I was thinking of lower frequencies which can sometimes go hundreds of kilometers without repeaters.

Bandiwdth, mostly.

The lower you go in frequency, the less bandwidth is available.

The entire "HF" spectrum is ~30 MHz. My Wi-Fi at home uses a wider channel than that.

The lower frequencies -- that will travel across the ocean, unaided -- don't have anywhere near the bandwidth necessary (to support the throughput that they need).

Re: Network Latencies and Speed of Light

#40

Post by andrepd »

paulddraper wrote: post #37
sgt101 wrote: post #31

Earlier quoted context omitted.

Which is why the regulators really need to get sharper with them vs. what they are doing to the economy. They are front running, destroying value and spending the money on a whole load of tat - a massive case of misallocation of capital. They need to be shuttered.

HFT, or Bitcoin?

Stop shoehorning and derailing the conversation please.
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