No requirement for layer3 for that. I’d bet money they’ll keep L3 out of space. nb On Sun, Jul 18, 2021 at 8:20 PM David Lang wrote: > Elon is talking about a viable path in the future being dishy - sat - sat > - > dishy > > They aren't there yet, but they are sure planning on it > > David Lang > > On Sun, 18 Jul 2021, Nick Buraglio wrote: > > > We keep saying “route”. What do we actually mean from a network stack > > perspective? Are we talking about relaying light / frames / electric or > do > > we mean actual packet routing, because there are obviously a lot of > > important distinctions there. > > I’m willing to bet that there is no routing (as in layer 3 packet > routing) > > at all except the Dish NAT all the way into their peering data center. > The > > ground stations are very likely RF to fiber wave division back to a > carrier > > hotel with no L3 buffering at all. That keeps latency very low (think > O-E-O > > and E-O transitions) and moves L3 buffering to two locations and keeps > the > > terrestrial network very easy to make redundant (optical protection, > etc.). > > > > nb > > > > On Fri, Jul 16, 2021 at 12:39 PM Jonathan Bennett < > > jonathanbennett@hackaday.com> wrote: > > > >> > >> > >> On Fri, Jul 16, 2021, 12:35 PM Nathan Owens wrote: > >> > >>> The other case where they could provide benefit is very long distance > >>> paths --- NY to Tokyo, Johannesburg to London, etc... but presumably at > >>> high cost, as the capacity will likely be much lower than submarine > cables. > >>> > >>>> > >> Or traffic between Starlink customers. A video call between me and > someone > >> else on the Starlink network is going to be drastically better if it can > >> route over the sats. > >> > >>> > >>>> On Fri, Jul 16, 2021 at 10:31 AM Mike Puchol > wrote: > >>> > >>>> Satellite optical links are useful to extend coverage to areas where > you > >>>> don’t have gateways - thus, they will introduce additional latency > compared > >>>> to two space segment hops (terminal to satellite -> satellite to > gateway). > >>>> If you have terminal to satellite, two optical hops, then final > satellite > >>>> to gateway, you will have more latency, not less. > >>>> > >>>> We are being “sold” optical links for what they are not IMHO. > >>>> > >>>> Best, > >>>> > >>>> Mike > >>>> On Jul 16, 2021, 19:29 +0200, Nathan Owens , wrote: > >>>> > >>>>> As there are more satellites, the up down time will get closer to > >>>> 4-5ms rather then the ~7ms you list > >>>> > >>>> Possibly, if you do steering to always jump to the lowest latency > >>>> satellite. > >>>> > >>>>> with laser relays in orbit, and terminal to terminal routing in > orbit, > >>>> there is the potential for the theoretical minimum to tend lower > >>>> Maybe for certain users really in the middle of nowhere, but I did the > >>>> best-case math for "bent pipe" in Seattle area, which is as good as > it gets. > >>>> > >>>> On Fri, Jul 16, 2021 at 10:24 AM David Lang wrote: > >>>> > >>>>> hey, it's a good attitude to have :-) > >>>>> > >>>>> Elon tends to set 'impossible' goals, miss the timeline a bit, and > come > >>>>> very > >>>>> close to the goal, if not exceed it. > >>>>> > >>>>> As there are more staellites, the up down time will get closer to > 4-5ms > >>>>> rather > >>>>> then the ~7ms you list, and with laser relays in orbit, and terminal > to > >>>>> terminal > >>>>> routing in orbit, there is the potential for the theoretical minimum > to > >>>>> tend > >>>>> lower, giving some headroom for other overhead but still being in the > >>>>> 20ms > >>>>> range. > >>>>> > >>>>> David Lang > >>>>> > >>>>> On Fri, 16 Jul 2021, Nathan Owens wrote: > >>>>> > >>>>>> Elon said "foolish packet routing" for things over 20ms! Which seems > >>>>> crazy > >>>>>> if you do some basic math: > >>>>>> > >>>>>> - Sat to User Terminal distance: 550-950km air/vacuum: 1.9 - 3.3ms > >>>>>> - Sat to GW distance: 550-950km air/vacuum: 1.9 - 3.3ms > >>>>>> - GW to PoP Distance: 50-800km fiber: 0.25 - 4ms > >>>>>> - PoP to Internet Distance: 50km fiber: 0.25 - 0.5ms > >>>>>> - Total one-way delay: 4.3 - 11.1ms > >>>>>> - Theoretical minimum RTT: 8.6ms - 22.2ms, call it 15.4ms > >>>>>> > >>>>>> This includes no transmission delay, queuing delay, > >>>>>> processing/fragmentation/reassembly/etc, and no time-division > >>>>> multiplexing. > >>>>>> > >>>>>> On Fri, Jul 16, 2021 at 10:09 AM David Lang wrote: > >>>>>> > >>>>>>> I think it depends on if you are looking at > datacenter-to-datacenter > >>>>>>> latency of > >>>>>>> home to remote datacenter latency :-) > >>>>>>> > >>>>>>> my rule of thumb for cross US ping time has been 80-100ms latency > >>>>> (but > >>>>>>> it's been > >>>>>>> a few years since I tested it). > >>>>>>> > >>>>>>> I note that an article I saw today said that Elon is saying that > >>>>> latency > >>>>>>> will > >>>>>>> improve significantly in the near future, that up/down latency is > >>>>> ~20ms > >>>>>>> and the > >>>>>>> additional delays pushing it to the 80ms range are 'stupid packet > >>>>> routing' > >>>>>>> problems that they are working on. > >>>>>>> > >>>>>>> If they are still in that level of optimization, it doesn't > surprise > >>>>> me > >>>>>>> that > >>>>>>> they haven't really focused on the bufferbloat issue, they have > more > >>>>>>> obvious > >>>>>>> stuff to fix first. > >>>>>>> > >>>>>>> David Lang > >>>>>>> > >>>>>>> > >>>>>>> On Fri, 16 Jul 2021, Wheelock, Ian wrote: > >>>>>>> > >>>>>>>> Date: Fri, 16 Jul 2021 10:21:52 +0000 > >>>>>>>> From: "Wheelock, Ian" > >>>>>>>> To: David Lang , David P. Reed < > dpreed@deepplum.com> > >>>>>>>> Cc: "starlink@lists.bufferbloat.net" < > >>>>> starlink@lists.bufferbloat.net> > >>>>>>>> Subject: Re: [Starlink] Starlink and bufferbloat status? > >>>>>>>> > >>>>>>>> Hi David > >>>>>>>> In terms of the Latency that David (Reed) mentioned for California > >>>>> to > >>>>>>> Massachusetts of about 17ms over the public internet, it seems a > bit > >>>>> faster > >>>>>>> than what I would expect. My own traceroute via my VDSL link shows > >>>>> 14ms > >>>>>>> just to get out of the operator network. > >>>>>>>> > >>>>>>>> https://www.wondernetwork.com is a handy tool for checking > >>>>> geographic > >>>>>>> ping perf between cities, and it shows a min of about 66ms for > pings > >>>>>>> between Boston and San Diego > >>>>>>> https://wondernetwork.com/pings/boston/San%20Diego (so about 33ms > >>>>> for > >>>>>>> 1-way transfer). > >>>>>>>> > >>>>>>>> Distance wise this is about 4,100 KM (2,500 M), and @2/3 speed of > >>>>> light > >>>>>>> (through a pure fibre link of that distance) the propagation time > is > >>>>> just > >>>>>>> over 20ms. If the network equipment between the Boston and San > Diego > >>>>> is > >>>>>>> factored in, with some buffering along the way, 33ms does seem > quite > >>>>>>> reasonable over the 20ms for speed of light in fibre for that 1-way > >>>>> transfer > >>>>>>>> > >>>>>>>> -Ian Wheelock > >>>>>>>> > >>>>>>>> From: Starlink on behalf > >>>>> of > >>>>>>> David Lang > >>>>>>>> Date: Friday 9 July 2021 at 23:59 > >>>>>>>> To: "David P. Reed" > >>>>>>>> Cc: "starlink@lists.bufferbloat.net" < > >>>>> starlink@lists.bufferbloat.net> > >>>>>>>> Subject: Re: [Starlink] Starlink and bufferbloat status? > >>>>>>>> > >>>>>>>> IIRC, the definition of 'low latency' for the FCC was something > like > >>>>>>> 100ms, and Musk was predicting <40ms. roughly competitive with > >>>>> landlines, > >>>>>>> and worlds better than geostationary satellite (and many > >>>>>>>> External (mailto:david@lang.hm) > >>>>>>>> > >>>>>>> > >>>>> > https://shared.outlook.inky.com/report?id=Y29tbXNjb3BlL2lhbi53aGVlbG9ja0Bjb21tc2NvcGUuY29tL2I1MzFjZDA4OTZmMWI0Yzc5NzdiOTIzNmY3MTAzM2MxLzE2MjU4NzE1NDkuNjU=#key=19e8545676e28e577c813de83a4cf1dc > >>>>>>> https://www.inky.com/banner-faq/ https://www.inky.com > >>>>>>>> > >>>>>>>> IIRC, the definition of 'low latency' for the FCC was something > like > >>>>>>> 100ms, and > >>>>>>>> Musk was predicting <40ms. > >>>>>>>> > >>>>>>>> roughly competitive with landlines, and worlds better than > >>>>> geostationary > >>>>>>>> satellite (and many wireless ISPs) > >>>>>>>> > >>>>>>>> but when doing any serious testing of latency, you need to be > wired > >>>>> to > >>>>>>> the > >>>>>>>> router, wifi introduces so much variability that it swamps the > >>>>> signal. > >>>>>>>> > >>>>>>>> David Lang > >>>>>>>> > >>>>>>>> On Fri, 9 Jul 2021, David P. Reed wrote: > >>>>>>>> > >>>>>>>>> Date: Fri, 9 Jul 2021 14:40:01 -0400 (EDT) > >>>>>>>>> From: David P. Reed > >>>>>>>>> To: starlink@lists.bufferbloat.net > >>>>>>>>> Subject: [Starlink] Starlink and bufferbloat status? > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> Early measurements of performance of Starlink have shown > >>>>> significant > >>>>>>> bufferbloat, as Dave Taht has shown. > >>>>>>>>> > >>>>>>>>> But... Starlink is a moving target. The bufferbloat isn't a > >>>>> hardware > >>>>>>> issue, it should be completely manageable, starting by simple > >>>>> firmware > >>>>>>> changes inside the Starlink system itself. For example, > implementing > >>>>>>> fq_codel so that bottleneck links just drop packets according to > the > >>>>> Best > >>>>>>> Practices RFC, > >>>>>>>>> > >>>>>>>>> So I'm hoping this has improved since Dave's measurements. How > >>>>> much has > >>>>>>> it improved? What's the current maximum packet latency under full > >>>>>>> load, Ive heard anecdotally that a friend of a friend gets 84 > msec. > >>>>> *ping > >>>>>>> times under full load*, but he wasn't using flent or some other > >>>>> measurement > >>>>>>> tool of good quality that gives a true number. > >>>>>>>>> > >>>>>>>>> 84 msec is not great - it's marginal for Zoom quality experience > >>>>> (you > >>>>>>> want latencies significantly less than 100 msec. as a rule of thumb > >>>>> for > >>>>>>> teleconferencing quality). But it is better than Dave's > measurements > >>>>> showed. > >>>>>>>>> > >>>>>>>>> Now Musk bragged that his network was "low latency" unlike other > >>>>> high > >>>>>>> speed services, which means low end-to-end latency. That got him > >>>>>>> permission from the FCC to operate Starlink at all. His number > was, I > >>>>>>> think, < 5 msec. 84 is a lot more than 5. (I didn't believe 5, > >>>>> because he > >>>>>>> probably meant just the time from the ground station to the > terminal > >>>>>>> through the satellite. But I regularly get 17 msec. between > >>>>> California and > >>>>>>> Massachusetts over the public Internet) > >>>>>>>>> > >>>>>>>>> So 84 might be the current status. That would mean that someone > at > >>>>>>> Srarlink might be paying some attention, but it is a long way from > >>>>> what > >>>>>>> Musk implied. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> PS: I forget the number of the RFC, but the number of packets > >>>>> queued on > >>>>>>> an egress link should be chosen by taking the hardware bottleneck > >>>>>>> throughput of any path, combined with an end-to-end Internet > >>>>> underlying > >>>>>>> delay of about 10 msec. to account for hops between source and > >>>>> destination. > >>>>>>> Lets say Starlink allocates 50 Mb/sec to each customer, packets are > >>>>> limited > >>>>>>> to 10,000 bits (1500 * 8), so the outbound queues should be limited > >>>>> to > >>>>>>> about 0.01 * 50,000,000 / 10,000, which comes out to about 250 > >>>>> packets from > >>>>>>> each terminal of buffering, total, in the path from terminal to > >>>>> public > >>>>>>> Internet, assuming the connection to the public Internet is not a > >>>>> problem. > >>>>>>>> _______________________________________________ > >>>>>>>> Starlink mailing list > >>>>>>>> Starlink@lists.bufferbloat.net > >>>>>>>> > >>>>>>> > >>>>> > https://secure-web.cisco.com/1sNc_-1HhGCW7xdirt_lAoAy5Nn5T6UA85Scjn5BR7QHXtumhrf6RKn78SuRJG7DUKI3duggU9g6hJKW-Ze07HTczYqB9mBpIeALqk5drQ7nMvM8K7JbWfUbPR7JSNrI75UjiNXQk0wslBfoOTvkMlRj5eMOZhps7DMGBRQTVAeTd5vwXoQtDgS6zLCcJkrcO2S9MRSCC4f1I17SzgQJIwqo3LEwuN6lD-pkX0MFLqGr2zzsHw5eapd-VBlHu5reC4-OEn2zHkb7HNzS1pcueF6tsUE1vFRsWs2SIOwU5MvbKe3J3Q6NRQ40cHI1AGd-i/https://lists.bufferbloat.net/listinfo/starlink > >>>>>>>> > >>>>>>>> _______________________________________________ > >>>>>>> Starlink mailing list > >>>>>>> Starlink@lists.bufferbloat.net > >>>>>>> https://lists.bufferbloat.net/listinfo/starlink > >>>>>>> > >>>>>> > >>>>> > >>>> _______________________________________________ > >>>> Starlink mailing list > >>>> Starlink@lists.bufferbloat.net > >>>> https://lists.bufferbloat.net/listinfo/starlink > >>>> > >>>> _______________________________________________ > >>> Starlink mailing list > >>> Starlink@lists.bufferbloat.net > >>> https://lists.bufferbloat.net/listinfo/starlink > >>> > >> _______________________________________________ > >> Starlink mailing list > >> Starlink@lists.bufferbloat.net > >> https://lists.bufferbloat.net/listinfo/starlink > >> > >_______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink >