181–190 of 223 posts
Earlier quoted context omitted.
Can you provide a source to this statement? The redundancy needed to transmit at desirable reliability with 50 % packet loss would, I imagine, very quickly eat into any millisecond gains -- even with theoretically optimal coding. Someone more familiar with Shannon than I could probably quickly back-of-the-napkin this.
Traders wouldn't use redundancy etc. Whenever a packet with info arrives, they would trade on that info (eg. "$MSFT stock is about to go down, so buy before it drops!"). If there is packet loss, then some info is lost, and therefore some profitable trading opportunities are missed. But thats okay. There are thousands of such opportunities each second - they can come from consumer 'order flow' - ie. information that s…
Earlier quoted context omitted.
You would have to map out the cables to do that. Light in fiber optic cable travels roughly 70% of the speed of light ~210,000 km/s Earth's circumferences is ~40,000 kilometers. Direct route from the other side of Earth to another would be roughly 100 milliseconds, round trip 200 ms.
Since light travels at 100% the speed of light in a vacuum (by definition), I have wondered if latency over far distances could be improved by sending the data through a constellation of satellites in low earth orbit instead. Though I suspect the set of tradeoffs here (much lower throughput, much higher cost, more jitter in the latency due to satellites constantly moving around relative to the terrestrial surface) pr…
Earlier quoted context omitted.
> Low-bandwidth/low-latency people tend to also demand high reliability and consistency. For trading applications, people will absolutely pay for a service that is hard down 75% of the time and has 50% packet loss the rest, but saves a millisecond over the fastest reliable line. Because otherwise someone else will be faster than you when the service is working. They can get reliability and consistency with a redundan…
Can you provide a source to this statement? The redundancy needed to transmit at desirable reliability with 50 % packet loss would, I imagine, very quickly eat into any millisecond gains -- even with theoretically optimal coding. Someone more familiar with Shannon than I could probably quickly back-of-the-napkin this.
https://www.latimes.com/business/la-fi-high-speed-trading-20...
https://arstechnica.com/information-technology/2016/11/priva...
https://en.wikipedia.org/wiki/TD-2#Reemergence
I'm not sure about the high packet loss statement, but it wouldn't suprise me that it's true if the latency is lower enough to get to take advantage of arbitrage opportunities often enough to justify the cost.
Earlier quoted context omitted.
You would have to map out the cables to do that. Light in fiber optic cable travels roughly 70% of the speed of light ~210,000 km/s Earth's circumferences is ~40,000 kilometers. Direct route from the other side of Earth to another would be roughly 100 milliseconds, round trip 200 ms.
Since light travels at 100% the speed of light in a vacuum (by definition), I have wondered if latency over far distances could be improved by sending the data through a constellation of satellites in low earth orbit instead. Though I suspect the set of tradeoffs here (much lower throughput, much higher cost, more jitter in the latency due to satellites constantly moving around relative to the terrestrial surface) pr…
Earlier quoted context omitted.
Author here - Interesting. Someone on X also gave this idea to me. Any good resources for how to accurately compute this?
The theoretical best latency would be something like speed_of_light_in_fiber/great_circle_distance_between_regions, both of which are pretty easy to find. The first is a constant you can look up, and the second you can compute from coordinates of each region pair.
Earlier quoted context omitted.
You would have to map out the cables to do that. Light in fiber optic cable travels roughly 70% of the speed of light ~210,000 km/s Earth's circumferences is ~40,000 kilometers. Direct route from the other side of Earth to another would be roughly 100 milliseconds, round trip 200 ms.
Since light travels at 100% the speed of light in a vacuum (by definition), I have wondered if latency over far distances could be improved by sending the data through a constellation of satellites in low earth orbit instead. Though I suspect the set of tradeoffs here (much lower throughput, much higher cost, more jitter in the latency due to satellites constantly moving around relative to the terrestrial surface) pr…
I think it's just too damn expensive for your average webapp to cut out ten milliseconds from backend latency.
Earlier quoted context omitted.
Since light travels at 100% the speed of light in a vacuum (by definition), I have wondered if latency over far distances could be improved by sending the data through a constellation of satellites in low earth orbit instead. Though I suspect the set of tradeoffs here (much lower throughput, much higher cost, more jitter in the latency due to satellites constantly moving around relative to the terrestrial surface) pr…
I am pretty sure this was one of the advertised strength of Starlink. Technically the journey is a bit longer, but because you can rely on the full speed of light you still come out ahead.
It would be really cool if it didn't just show the ping, but how much worse it is compared to the theoretical optimum (speed of light in fiber optic medium, which I believe is about 30% slower than c). I raise this because I've been in multiple system architecture meetings where people were complaining about latency between data centers, only to later realize that it was pretty close to what is theoretically possible…
Doesn't look like this is a ping[0]! Which is good. Rather it is a socket stream connecting over tcp/443. Ping (ICMP) would be a poor metric. [0] https://github.com/mda590/cloudping.co/blob/8918ee8d7e632765...
but you're right
It is insane to see this and conceptualize that you can send data across the world and back in under 500ms. Imagine telling someone that 100 years ago.