Is it 15ms to the satellite? If so, that's like 30ms to land, which would negatively impact gaming if it still needs to travel from where it lands to the end goal (via normal pathing?)
1000 km / speed of light = 3.34 ms. Suppose you want to ping a server next door to you and your ISP is a satellite 1000 km away. The distance your signal travels is 1000km from client to satellite, 1000 km from satellite to server, 1000km from server to satellite and 1000km satellite back to client. 4000 km at the speed of light is 13.34ms (the transceiving latency is probably negligible in comparison, though I'm not 100% sure about the DSP requirements for this sort of system)
If the target server is far away and the signal goes 7000 km from satellite to satellite in space before coming back down, then your signal it will need at least 46.7ms more in space for a 14km round trip in space, which results in a minimum possible ping of 60ms to ping a server 7000 km away. Fiber-optics are 30% slower than radio links, so this 60ms minimum is 10% lower latency than the best fiber-optics can do: (7000 km / .7 speed-of-light) = 66ms
If the distance to your server is 2.333x the distance to your satellite you will have lower latency with radio than fiber optics. Bringing the altitude of the satellites down will make a big difference, but you also need a lot more of them in a constellation to have low average distances.
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.
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.
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).
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.
Not sure what you are talking about. 900 miles is ~1500km, 1500km at the speed of light in fiber (2/3 of SOL) takes 7,5 milliseconds, so 15ms roundtrip.
But I don't see why it's relevant. Forwarding in modern ISP routers is on the tens to hundreds of microseconds level, even if there are many hops it does not add up to that much. So what he has is likely not "switching delay", and even saying that 11ms is 100% switching delay when it's the same city (low amount of hops even if multiple ISP's are involved) is just ridiculous.
Took that number (it was for one way trip though) from memory, might be scrambled. Just checked, RTT 17ms with 3ms jitter for me.
22ms RTT is still too much though. Even with centralized network for cross-border traffic like in my country, there are IXs way closer than those 1500km to any town on european part and obviously to the East of Urals (the longest distance between IXPs is ~3000km for Krasnoyarsk-Khabarovsk, the longest distance to the closest IXP of 1500km have Norilsk - the most northern city on the globe and it's satellite Dudinka).
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.
> 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.
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_popula...
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.
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.
The 30ms figure is just the earth->satellite->earth part though. It still has to go through terrestrial wires to the server, and then be processed, and back through wires to the transmitter.
30ms would be you and the game server both on Starlink, on the same satellite. Otherwise, you have to add that to the latency between the ground station and the target server.
IIRC, the plan with Starlink is to have many stations that are supposedly easy to operate in many large-ish datacenters in major areas as opposed to systems like Iridium which have few, complex downlink stations in comparison.
Maybe from me to a geographic location 400 miles away, yes. But what about 4k miles away, like coast to coast?
That would probably depend on how many satellites it has to bounce through and how far it has to travel terrestrial, but I would think there is a geographic distance where that 30ms is faster.
