Why aren't HFT firms using short wave radio (DXing)? I suppose low-orbit satellite-to-satellite would probably beat fibre for anything over ~4000km too.
The throughput probably isn't high enough.
Network Latencies and Speed of Light
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Re: Network Latencies and Speed of Light
#22Serious question: for a transatlantic network, would it ever make sense to do something along the lines of buoy + helium balloons + laser or microwave? Or in a similar vain, would it make sense to attach microwave 'towers' to shipping vessels? I could see something like that work really well for the HFT world, where some clever hacks could make use of an unstable, but extremely low latency connections.
It depends what problem you're trying to solve.
For inter-landmass traffic, my gut feel is bandwidth is the bigger concern.
The latencies we see now (as noted in TFA) are not that far from theoretical limits. I'd suggest responsiveness is best solved further up the stack -- and it's what most organisations have done / are doing.
Basically you don't want to run chatty protocols over high RTT networks, and people are slowing getting this ... but many orgs are stuck with HTTP, MAPI/MoH, SMB/CIFS consuming most of their WAN bandwidth.
Re: Network Latencies and Speed of Light
#23going through the earth is a shorter distance but unfortunately light speed is slower that way
Re: Network Latencies and Speed of Light
#24Why aren't HFT firms using short wave radio (DXing)? I suppose low-orbit satellite-to-satellite would probably beat fibre for anything over ~4000km too.
That's an interesting one. Maybe complicating instructions might take too long to encode, but making it a simple buy/sell trigger for one particular security could work? But also going over too long a distance means the stock markets are closed in that part of the world.
There is also a satellite company LeoSat that was trying to build a low latency long distance network of low flying satellites with laser links between them. Guessing that's a "tad" :-) (few billion) more expensive than a pair of shortwave transceivers. But if money is not an issue they say they can do 1.5x faster than terrestrial speed:
http://leosat.com/media/1115/leosat-finance.pdf
100ms NY to Tokyo, for example. Not bad.
Re: Network Latencies and Speed of Light
#25He mentions an overhead of about 11ms in a cross-country network, which may be insignificant in the 35ms overall latency.
But, much of the infrastructure is communicated to regional servers or local CDNs, not cross country. A game server might split loads across east-coast servers and west-coast servers to improve responsiveness. In those cases, it's not unfeasible to see a 2ms-5ms speed-of-light latency. And that's where those 11ms really starts to affect user experience, since now you're looking at latencies that can cut into your 60fps frame rates. (or local video-chat services or even websites)
Re: Network Latencies and Speed of Light
#26Re: Network Latencies and Speed of Light
#27Why aren't HFT firms using short wave radio (DXing)? I suppose low-orbit satellite-to-satellite would probably beat fibre for anything over ~4000km too.
> 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
Re: Network Latencies and Speed of Light
#28going through the earth is a shorter distance but unfortunately light speed is slower that way
Why is light slower that way?
Re: Network Latencies and Speed of Light
#29He mentions an overhead of about 11ms in a cross-country network, which may be insignificant in the 35ms overall latency. But, much of the infrastructure is communicated to regional servers or local CDNs, not cross country. A game server might split loads across east-coast servers and west-coast servers to improve responsiveness. In those cases, it's not unfeasible to see a 2ms-5ms speed-of-light latency. And that's…
FPS won’t be reduced by latency increases, responsiveness will though.
Re: Network Latencies and Speed of Light
#30Why aren't HFT firms using short wave radio (DXing)? I suppose low-orbit satellite-to-satellite would probably beat fibre for anything over ~4000km too.
> 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.