4 ms·

But for something more realistic for gaming, a player in Boston hitting a server in NY. The fiber message travels something like 200 miles, while the satellite

But for something more realistic for gaming, a player in Boston hitting a server in NY. The fiber message travels something like 200 miles, while the satellite message travels 2,200 miles.

amirhirsch 8y ago
Boston to New York is 215mi or a 430 mile round trip. At 200 miles up where they intend to put the satellites orbiting over major cities, it's going to be about 1000 mile round trip. I thought that the US servers for most games are in the middle of the country to get the best average ping for a cross-country audience. Blizzard is like Chicago and Texas.
- penagwin 8y ago
  Not usually. In my experience, they usually follow the typical popular datacenter areas e.g. East Coast/West Coast. I've mostly only seen really popular games offer Central locations like Dallas/Chicago. But it's getting a lot better now that vultr (COD uses them) and other VPS providers get more and more locations.
- kbenson 8y ago
  > Boston to New York is 215mi or a 430 mile round trip. Assuming terrestrial lines travel as the crow flies, which is not all that likely (but probably not too far off). > At 200 miles up where they intend to put the satellites orbiting over major cities, it's going to be about 1000 mile round trip. Other people here are noting that fiber signals travel at ~70% the speed of light, while radio waves travel at very close to the speed of light. If that's true, it puts the optimal time for land based optical communication at ~3.3ms[1] ms, while the optimal time for a low orbit satellite at ~5.4ms[2] (if I didn't screw up the math). That's slower, but not by a whole lot, so it might even be better than you're predicting. Also, are people actually getting sub 4ms round trip times between Boston and New York? If not, then the difference here might be entirely subsumed by other factors. 1: 430 Miles / 186,000 M/s / 0.70 = 0.0033 s 2: 1000 Miles / 186,000 Miles/s = 0.0054 s
- maccam94 8y ago
  Nope, the biggest AWS region is in Virginia (as well as a bunch of others, energy is cheap there). There are also lots of datacenters in Dallas, TX and San Jose, CA. NYC has a lot of connectivity (throughout the northeast, and transatlantic) but the cost of real estate is so high that it is uneconomical to operate lots of large datacenters there. The majority of the population in the US is in the eastern half (1/3 in states on the East coast), so you don't actually decrease median latency by putting datacenters in the geographic center: https://commons.wikimedia.org/wiki/File:United_States_population_distribution_2000_census.png https://commons.wikimedia.org/wiki/File:United_States_popula...
  - jjeaff 8y ago
    Nope, the mean population center of the contiguous United States is somewhere west of St. Louis. https://en.wikipedia.org/wiki/Mean_center_of_the_United_States_population https://en.wikipedia.org/wiki/Mean_center_of_the_United_Stat... Actually not too far away from the geographic center which is somewhere in Kansas.
    - maccam94 8y ago
      That doesn't disagree with what I said. The majority is still in the East (the mean is East of the geographic center), and you don't want to optimize for average latency anyway. You'll get the best median latency with two datacenters by putting one on the mid-Atlantic coast (~180M people East of the Mississippi) and one on the mid-Pacific coast (another 50M in Pacific Coast states). That means the latency for ~2/3 of the population is way lower, and the max latency is still about the same as putting them in the center of the country.
CydeWeys 8y ago
Radio waves are faster than light going through a fiber optic cable, and the satellite mesh network will have fewer hops (switching packets on fiber is expensive time-wise). The difference in latency won't be nearly as bad as a naive comparison of these two numbers would suggest. Depending on what hops your terrestrial traffic is going through, the satellite transmission could well be faster. To give you a trivial example, I'm seeing 11 ms ping right now to a server within my own city, that's only a couple miles away. This is ~0% signal transmission delay and ~100% switching delay.
- Hikikomori 8y ago
  It's still transmission delay, you are underestimating how fast routers forward packets today. Likely the server has a different provider and them and your ISP does not peer in your city, so you have to go somewhere else where they peer (or where their transit peers).
  - chupasaurus 8y ago
    I think no ISP would connect to others with a huge coil of fiber to add that amount of latency.
    - Hikikomori 8y ago
      No? But they do not connect to each other in every city either, which is why you can get this delay even if both parties are in the same city.
      - chupasaurus 8y ago
        All the uplinks of my ISP with one exception (carrying traffic through various lines up to european IXs) are connected to the Internet through the same MSK-IX which is 900 miles away from my city and adds 4ms latency. I don't think GGP's traffic route is that long though.
        8y ago
username444 8y ago
So maybe satellites simply aren't the best-use case for gaming? I don't think Elon is counting on gaming to be the backbone of this service.

But for something more realistic for gaming, a player in Boston hitting a server in NY. The fiber message travels something like 200 miles, while the satellite message travels 2,200 miles.

amirhirsch 8y ago

Boston to New York is 215mi or a 430 mile round trip. At 200 miles up where they intend to put the satellites orbiting over major cities, it's going to be about 1000 mile round trip. I thought that the US servers for most games are in the middle of the country to get the best average ping for a cross-country audience. Blizzard is like Chicago and Texas.

penagwin 8y ago
Not usually. In my experience, they usually follow the typical popular datacenter areas e.g. East Coast/West Coast. I've mostly only seen really popular games offer Central locations like Dallas/Chicago. But it's getting a lot better now that vultr (COD uses them) and other VPS providers get more and more locations.
kbenson 8y ago
> Boston to New York is 215mi or a 430 mile round trip. Assuming terrestrial lines travel as the crow flies, which is not all that likely (but probably not too far off). > At 200 miles up where they intend to put the satellites orbiting over major cities, it's going to be about 1000 mile round trip. Other people here are noting that fiber signals travel at ~70% the speed of light, while radio waves travel at very close to the speed of light. If that's true, it puts the optimal time for land based optical communication at ~3.3ms[1] ms, while the optimal time for a low orbit satellite at ~5.4ms[2] (if I didn't screw up the math). That's slower, but not by a whole lot, so it might even be better than you're predicting. Also, are people actually getting sub 4ms round trip times between Boston and New York? If not, then the difference here might be entirely subsumed by other factors. 1: 430 Miles / 186,000 M/s / 0.70 = 0.0033 s 2: 1000 Miles / 186,000 Miles/s = 0.0054 s
maccam94 8y ago
Nope, the biggest AWS region is in Virginia (as well as a bunch of others, energy is cheap there). There are also lots of datacenters in Dallas, TX and San Jose, CA. NYC has a lot of connectivity (throughout the northeast, and transatlantic) but the cost of real estate is so high that it is uneconomical to operate lots of large datacenters there. The majority of the population in the US is in the eastern half (1/3 in states on the East coast), so you don't actually decrease median latency by putting datacenters in the geographic center: https://commons.wikimedia.org/wiki/File:United_States_population_distribution_2000_census.png https://commons.wikimedia.org/wiki/File:United_States_popula...
- jjeaff 8y ago
  Nope, the mean population center of the contiguous United States is somewhere west of St. Louis. https://en.wikipedia.org/wiki/Mean_center_of_the_United_States_population https://en.wikipedia.org/wiki/Mean_center_of_the_United_Stat... Actually not too far away from the geographic center which is somewhere in Kansas.
  - maccam94 8y ago
    That doesn't disagree with what I said. The majority is still in the East (the mean is East of the geographic center), and you don't want to optimize for average latency anyway. You'll get the best median latency with two datacenters by putting one on the mid-Atlantic coast (~180M people East of the Mississippi) and one on the mid-Pacific coast (another 50M in Pacific Coast states). That means the latency for ~2/3 of the population is way lower, and the max latency is still about the same as putting them in the center of the country.

CydeWeys 8y ago

Radio waves are faster than light going through a fiber optic cable, and the satellite mesh network will have fewer hops (switching packets on fiber is expensive time-wise). The difference in latency won't be nearly as bad as a naive comparison of these two numbers would suggest. Depending on what hops your terrestrial traffic is going through, the satellite transmission could well be faster. To give you a trivial example, I'm seeing 11 ms ping right now to a server within my own city, that's only a couple miles away. This is ~0% signal transmission delay and ~100% switching delay.

Hikikomori 8y ago
It's still transmission delay, you are underestimating how fast routers forward packets today. Likely the server has a different provider and them and your ISP does not peer in your city, so you have to go somewhere else where they peer (or where their transit peers).
- chupasaurus 8y ago
  I think no ISP would connect to others with a huge coil of fiber to add that amount of latency.
  - Hikikomori 8y ago
    No? But they do not connect to each other in every city either, which is why you can get this delay even if both parties are in the same city.
    - chupasaurus 8y ago
      All the uplinks of my ISP with one exception (carrying traffic through various lines up to european IXs) are connected to the Internet through the same MSK-IX which is 900 miles away from my city and adds 4ms latency. I don't think GGP's traffic route is that long though.
      - 8y ago

username444 8y ago

So maybe satellites simply aren't the best-use case for gaming? I don't think Elon is counting on gaming to be the backbone of this service.