Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Network Latencies and Speed of Light

fgiesen.wordpress.com

Post reply on HN
Print view View original

11–20 of 50 posts

Re: Network Latencies and Speed of Light

#11

Post by itcmcgrath »

bpchaps wrote: post #5

Serious 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.

I doubt that would be lower latency. Even forgetting the physics and curvature issues, you'll end up with many more hops which is going slow it down due to processing and retransmission delays.

Re: Network Latencies and Speed of Light

#13

Post by carterehsmith »

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.

Also, radio towers; because, the fiber (or whatever) cables usually zigzag following the roads or utility poles; meantime, the two radio towers can exchange radio waves traveling in a straight line.

Re: Network Latencies and Speed of Light

#14

Post by 0xcde4c3db »

RyanShook wrote: post #10

What about all the hops your signal has to take to make the round trip? Couldn’t those be optimized or sped up? Is copper latency really equivalent to fiber?

> Is copper latency really equivalent to fiber?

Notwithstanding differences between specific types of cables and transceivers, yes, the rule of thumb is that they're roughly equivalent. The big advantages with fiber mostly come with being physically smaller for a given bandwidth (e.g. more bandwidth per square inch of conduit cross-section, more bandwidth per cable weight for vertical or suspended runs) and needing less active equipment between any two points in the network (e.g. PON, long-haul single-mode runs).

Re: Network Latencies and Speed of Light

#15

Post by xxxdarrenxxx »

What about a potential quantum link.

Quantum is currently talked about a lot in relation to computer processing, but I actually got interested into quantum physics over a decade ago through scientfic work being done with a goal off pseudo-teleportation.

They experimented with the vibrating? particles in such a way, that they would "resonate" particles an x distance away, potentially even making distance irrelevant. All happening at a 1:1 ratio.

I belive it's called quantum entanglement

Re: Network Latencies and Speed of Light

#16

Post by newman8r »

bpchaps wrote: post #5

Serious 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.

the current longest microwave links are only a few hundred kilometers apart if I recall correctly (http://www.marketwired.com/press-release/exalt-sets-new-worl...)

so you'd be talking about MANY links to achieve a transatlantic connection. Optical links would have to be even closer.

Re: Network Latencies and Speed of Light

#17

Post by wmf »

itcmcgrath wrote: post #11
bpchaps wrote: post #5

Serious 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.

I doubt that would be lower latency. Even forgetting the physics and curvature issues, you'll end up with many more hops which is going slow it down due to processing and retransmission delays.

Microwave is faster even though it requires more hops.

Re: Network Latencies and Speed of Light

#18

Post by dgoldstein0 »

6d6b73 wrote: post #4

Well, we already have tech that can provide us with virtually lowest latency physically possible without having to dig any tunnels - high frequency radio waves :) Of course bandwidth could be a problem but for pings it should be enough.

The point isn't to optimize for pings. It's to optimize for real use cases - video chat, web browsing, music and video streaming, etc. Most of these applications need at least a moderate amount of bandwidth.
Post reply on HN