4 ms·

It would be interesting to also see what the lowest possible latency between the regions would be so you can see how much overhead the interchanges are adding.

It would be interesting to also see what the lowest possible latency between the regions would be so you can see how much overhead the interchanges are adding. For example, the distance between us-east-1 and us-west-1 is approximately 2,500 miles. Light travels at 186,000 miles/second, so that's 13 milliseconds one-way. So the fastest possible TCP SYN/ACK/SYNACK is 39 milliseconds between the two DCs just to establish a connection.

scottlamb 6y ago
Light travels at 186,000 miles/second in a vacuum. A quick websearch says fiber's index of refraction is ~1.467. One round trip then takes 39 ms (coincidentally the same number you said for 3 legs), vs the 62.36 ms on this chart. In theory they could reduce latency by ~23 ms then with a truly direct path. To do better would require abandoning fiber.
- legulere 6y ago
  Hollow fiber would almost reach full light speed: https://www.nojitter.com/enterprise-networking/hollow-fiber-new-option-low-latency https://www.nojitter.com/enterprise-networking/hollow-fiber-... https://www.rp-photonics.com/hollow_core_fibers.html https://www.rp-photonics.com/hollow_core_fibers.html
  - scottlamb 6y ago
    Neat! I'd never heard of that. I look forward to the day when it's generally used rather than yet another cool technology wasted on stupid high-frequency trading.
    - virtuallynathan 6y ago
      It's actually being deployed for HFT in London right now by euNetworks.
dheera 6y ago
I spent about 15 minutes trying to create a custom Distance function in Google Sheets: const DISTANCE = function(a, b) { [latA, lonA] = a.split(","); [latB, lonB] = b.split(","); latA=parseFloat(latA); lonA=parseFloat(lonA); latB=parseFloat(latB); lonB=parseFloat(lonB); return 2 * 6371000 * ASIN(SQRT((SIN((latB*(3.14159/180)-latA*(3.14159/180))/2))^2+COS(latB*(3.14159/180))*COS(latA*(3.14159/180))*SIN(((lonB*(3.14159/180)-lonA*(3.14159/180))/2))^2)) } So that I could just paste concatenated "lat,lon" coords in place of the AWS region names and just compute e.g. =DISTANCE(A2,B1) Into a second sheet, and then just divide the first sheet by the second sheet as a third sheet. but I kept getting some "#NAME" error and I don't have time to figure it out. Bad UX, Google. This should have been easy. Better yet, you're freaking Google, why isn't there a DISTANCE("Hong Kong", "Singapore", "straightline") function? I have to get back to work but if someone can figure the rest of this out please comment back.
- bradknowles 6y ago
  If you’re going to calculate distances between two geological locations, then you want to calculate Great Circle distances, as that will be the shortest path at the surface of the planet. A straight line distance might require tunneling down into the planet a surprising amount of distance, and is an absolute lower bound on the possible distance between the two points, but is not a realistic distance that could actually be achieved in most cases.
  - dheera 6y ago
    The formula above should be great circle distance, if I didn't screw it up.

scottlamb 6y ago

Light travels at 186,000 miles/second in a vacuum. A quick websearch says fiber's index of refraction is ~1.467. One round trip then takes 39 ms (coincidentally the same number you said for 3 legs), vs the 62.36 ms on this chart. In theory they could reduce latency by ~23 ms then with a truly direct path. To do better would require abandoning fiber.

legulere 6y ago
Hollow fiber would almost reach full light speed: https://www.nojitter.com/enterprise-networking/hollow-fiber-new-option-low-latency https://www.nojitter.com/enterprise-networking/hollow-fiber-... https://www.rp-photonics.com/hollow_core_fibers.html https://www.rp-photonics.com/hollow_core_fibers.html
- scottlamb 6y ago
  Neat! I'd never heard of that. I look forward to the day when it's generally used rather than yet another cool technology wasted on stupid high-frequency trading.
  - virtuallynathan 6y ago
    It's actually being deployed for HFT in London right now by euNetworks.

dheera 6y ago

I spent about 15 minutes trying to create a custom Distance function in Google Sheets: const DISTANCE = function(a, b) { [latA, lonA] = a.split(","); [latB, lonB] = b.split(","); latA=parseFloat(latA); lonA=parseFloat(lonA); latB=parseFloat(latB); lonB=parseFloat(lonB); return 2 * 6371000 * ASIN(SQRT((SIN((latB*(3.14159/180)-latA*(3.14159/180))/2))^2+COS(latB*(3.14159/180))*COS(latA*(3.14159/180))*SIN(((lonB*(3.14159/180)-lonA*(3.14159/180))/2))^2)) } So that I could just paste concatenated "lat,lon" coords in place of the AWS region names and just compute e.g. =DISTANCE(A2,B1) Into a second sheet, and then just divide the first sheet by the second sheet as a third sheet. but I kept getting some "#NAME" error and I don't have time to figure it out. Bad UX, Google. This should have been easy. Better yet, you're freaking Google, why isn't there a DISTANCE("Hong Kong", "Singapore", "straightline") function? I have to get back to work but if someone can figure the rest of this out please comment back.

bradknowles 6y ago
If you’re going to calculate distances between two geological locations, then you want to calculate Great Circle distances, as that will be the shortest path at the surface of the planet. A straight line distance might require tunneling down into the planet a surprising amount of distance, and is an absolute lower bound on the possible distance between the two points, but is not a realistic distance that could actually be achieved in most cases.
- dheera 6y ago
  The formula above should be great circle distance, if I didn't screw it up.