Re:Musk files to provide Internet service from space
by x0054 on Tuesday June 09, 2015 @10:24PM
(#9689709)
Hmm, interesting. Well, I have Exede Satellite service as my ISP (best I can get) and my best latency, to any server, is 800ms. The way I figure it, 35,786 km / 300 miles per ms would be 120ms up * 4 for the round trip. So that's 480ms, plus another 20ms-100ms to a google or another large server. So that's theoretical latency of 600ms, so where are the other 200ms of latency coming from! :(
I am wondering because I maintain some linux servers for some of my projects, and any time I need to do something serious, I have to drive to a coffee shop and borrow their connection. SSH over 800ms latency is frustrating, to say the least.
Re:Musk files to provide Internet service from space
by roamingryan on Tuesday June 09, 2015 @10:53PM
(#9689813)
Much of the remaining latency is likely coming from FEC and interleaving needed for the RF links.
http://en.wikipedia.org/wiki/Forward_error_correction#Interl...
Re:Musk files to provide Internet service from space
by havatar on Tuesday June 09, 2015 @10:38PM
(#9689759)
look into mosh, a ssh replacement for high latency connections.
Re:Musk files to provide Internet service from space
by azernik on Tuesday June 09, 2015 @11:08PM
(#9689850)
And the other disadvantage is more expensive and complicated ground equipment that can handle changing angle to satellites and handoff on three order of every several minutes. But I imagine that's only getting cheaper...
As described in this article, the SpaceX constellation would be in a much lower orbit. The advantage is a much faster ping time (say, around 10 ms). The disadvantage is you need a large number of satellites to provide continuous coverage for the entire earth...but that's less of a disadvantage if your company also launches rockets.