[xoa]

One interesting upcoming latency twist to this will be when the Starlink inter-sat optical links go online for the whole network. Version 0.9 is already used (and required) for polar and new batches are all launching with them, but I don't think they've hit critical mass yet to bring it up. Once they do though that will be a significant shift for anyone where intercontinental servers form a significant part of their usage. Speed of light in conventional fiber is only about 70% c, and of course for the vast majority of people the actual path their packets take through the network is very far from ideal great circle path between two points on the globe (ie., they will first have to travel to the nearest hub then nearest subocean link which in some cases could add massive travel distance).

But within the Starlink network signals will go essentially 100% c, and as the constellation approaches design capacity the paths will get closer to ideal too (at least to the nearest ground station). At long enough range the 40% speed advantage alone will make up for orbital RTT penalty even before path savings which means Starlink will be able to offer much lower latency then fiber. I think it'll be the first time though where we see a weird split where your local connection speed is no longer the sole deciding factor and you can actually see a radical latency split between local and very long range traffic for two different WAN types.

[virtuallynathan]

> Once they do though that will be a significant shift for anyone where intercontinental servers form a significant part of their usage.

I have strong doubts this capacity will be used for random user traffic. It's worth much more to use it to serve oceans, poles, islands, and areas where ground stations can't be built (yet). Other capacity could easily be sold to HFT firms, etc.

[cycomanic]

I'm not sure I buy this. There is a number of aspects you have not considered here. For the intersatellite links very hop will include an optical/electrical/optical conversion with FEC overheads etc. There is also the question of nearest ground station. It's not clear how many ground stations there are and how far they are from the server you want to connect to (especially considering that they might need to go to a backup station due to weather). It's also still unclear to me how much latency the routing will add, those satellites move pretty fast so during a connection you will likely have to make quite a few handovers, I doubt that you can hold an optimal path the whole time (my suspicion is that we will observe the same as observed in the article, somewhat higher latency with significant variation). That said they are clearly better than GEO, but compared to fibre they will always be niche.

[hunterb123]

> It's not clear how many ground stations there are and how far they are from the server you want to connect to

https://www.google.com/maps/d/viewer?mid=1H1x8jZs8vfjy60TvKg...

Personally, I'm excited to see a latency reduction for across the pond comms.

I don't see much reason to be pessimistic about it, we shall see!

[mhandley]

It will be very interesting to see how they manage queuing across the network of ISLs. The latency benefits can be real, but only if they don't allow queues to build in the satellites themselves. It's not too hard if you run the network at low utilization, but that would make it rather expensive. Running such a dynamic and meshy wide-area network at high utilization without significant queuing in the nodes is currently an unsolved problem in the networking research community. I do think it can be done (I have my own ideas how), but it's definitely not something that current networking algorithms can handle.

[greesil]

Every hop in the network is going to add latency though. Your calculation doesn't include this.

[zamadatix]

This is also true of links on the ground, you can't get very far without at least running DCM or other active optical components which add time as well. How it factors between the two really comes down to exactly how it's going to be implemented, particularly on the Starlink side. There's a lot of "could" in terms of getting lower latency than ground links but that doesn't mean it's actually the preferred metric they'll want to chase with their system.