Eli5 How come it is not possible to have fast internet across the globe so players from different continents can play together with good ping (<100ms)?
The governments of many countries have not approved Starlink yet, otherwise it’s absolutely possible.
Starlink has under 40ms of ping usually.
Speed of light.
Earth’s circumference is about 40,000km, so the distance between two points on Earth can be up to 20,000km. Even if you could deliver information at the speed of light between these two points, it would still takes 133ms for a message to go back and forth, and that’s ignoring and other latencies. In practice, data travels through fiber optic at about 2/3 the speed of light, so it would take even longer.
A ping is how fast a request from your computer arrives at the remote computer, and a reply reaches you from that remote computer. So it’s pretty much twice the amount needed for one way communication.
You are limited by how fast data travels through fiber cables and through copper cables.
Through fiber cables, the data runs at speeds slightly slower than the speed of light… if the speed of light is 299 792 458 meters/s, you could assume the data would travel at around 275-280,000 km/s or 280 km/ ms
But your data incurs some additional delay as it travels from node to node, as your data merges with data from other provides and “squeezed” through cables.
Currently, you are connected through copper of fiber cables to some equipment of your Internet Service Provider (ISP) in your apartment building or in the neighborhood, from there your data is combined with data from other subscribers and goes to a datacenter of your ISP where there are multiple connections to other ISPs or to various exchanges which connect ISPs so that data can be passed between them.
At some point, if you want the data to go to another continent, the data will have to go through a fiber cable that goes through the ocean. How fast your data travels through these ocean cables depends entirely on how much your ISP is willing to pay, as there isn’t an infinite amount of bandwidth available.
There are multiple such fiber cables, and people that put those fibers there in the ocean and maintain them, and rent capacity to ISPs… your ISP will rent some capacity and use that capacity for the subscribers it has.
For example a company may have a 40 gbps fiber cable and rents 1 gbps (1000 mbps) to your ISP.
Your ISP may collect data from a lot of subscribers, and this data may be 0.9 gbps one second, and may be 1.2 gbps the next second … the hardware equipment may “delay” your data or other subscribers’ data for a few ms when the 1 gbps capacity of the fiber is reached.
So even though in theory the data should travel on that fiber cable from start to finish in 30ms, it may take 35-50 ms for the data to actually arrive at the other end, if the hardware takes a few milliseconds to find some space for your data to go through the cable.
Some people say Starlink could be a solution. Partially yes, it can reduce the latency, but in reality it’s not much better.
You may have a few ms of savings because your data goes directly above to a satellite above your head instead of going through multiple devices to your ISP. The data may travel a bit faster in space hopping between satellites, but that’s debatable, as we don’t know exactly how much processing one satellite needs in order to pass your data to another satellite, and you don’t know through how many satellites the data jumps until it goes down to Earth.
And then, you also depend on the base stations on Earth.. The data goes down to various stations spread around the world, which then deliver your data through regular fiber cables to various ISPs.
For example, me in Romania may send the data directly above my head to a Starlink satellite, and the data may hop from satellite to satellite to one above Chicago where Starlink has a station, the data comes down in Chicago and then it may go through regular fiber cables to New York, for around 700-900 miles, so that’s some extra ms of latency.
There are two issues:
1) The speed of electricity (or, in the case of optical fibre, the speed of light).
2) The ‘hops’ between various switches and data centers that route your packets to and from the correct place.
If you were trying to play on a server the other side of the world, where the entire length of the connection around the world was fibre and there were absolutely no hops in between, it would still take around 200ms for a simple ping to get back to you. This is based on the world’s circumference being around 40,000km and the speed of light in fibre being around 200,000km/s.
But this is just the theoretical minimum. In practice you need to add in multiple hops in data centers and almost certainly some sections being on much slower copper wiring.