> On 11 Jun, 2020, at 7:03 pm, David P. Reed <[email protected]> wrote: > > So, what do you think the latency (including bloat in the satellites) will > be? My guess is > 2000 msec, based on the experience with Apple on ATT > Wireless back when it was rolled out (at 10 am, in each of 5 cities I tested, > repeatedly with smokeping, for 24 hour periods, the ATT Wireless access > network experienced ping time grew to 2000 msec., and then to 4000 by mid day > - true lag-under-load, with absolutely zero lost packets!) > > I get that SpaceX is predicting low latency by estimating physical distance > and perfect routing in their LEO constellation. Possibly it is feasible to > achieve this if there is zero load over a fixed path. But networks aren't > physical, though hardware designers seem to think they are. > > Anyone know ANY reason to expect better from Musk's clown car parade?
Speaking strictly from a theoretical perspective, I don't see any reason why they shouldn't be able to offer latency that is "normally" below 100ms (to a regional PoP, not between two arbitrary points on the globe). The satellites will be much closer to any given ground station than a GEO satellite, the latter typically adding 500ms to the path due mostly to physical distance. All that is needed is to keep queue delays reasonably under control, and there's any number of AQMs that can help with that. Clearly ATT Wireless did not perform any bufferbloat mitigation at all. I have no insight or visibility into anything they're *actually* doing, though. Can anyone dig up anything about that? - Jonathan Morton _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
