[Starlink] APNIC56 last week
David Lang
david at lang.hm
Mon Sep 25 04:59:03 EDT 2023
On Mon, 25 Sep 2023, Alexandre Petrescu wrote:
> Apart the AI's inability aspect, it stays interesting if future LEO Internet
> access systems competes to fiber in the right range.
wired (including fiber) is going to beat wireless pretty much anywhere it's
available. Wireless (and LEO) have the advantage that it's EXPENSIVE to run
wires, so they start to shine when the use density decreases (and even there,
there will be areas where 'fiber is bing run down this road anyway, so let's
offer service to people along the way to earn a few penny's and some good PR)
the quirk where very long range communication can be slightly lower round-trip
time by first hopping up into space is balanced by the more limited bandwidth
available through that space connection (you have to get through miles of
atmosphere, and that's going to limit your throughput compared to millimeters to
get into the fiber)
> The timestamped technologies should be compared. Starlink today's 20ms
> should be compared to today's advanced 5G 1ms, and not to 4G 50ms. Future
> LEO Internet access should be compared to future 6G terrestrial and future
> FTTH, because they also evolve.
True, but when you are looking at limits imposed by known physics, it's a pretty
safe bet. Yes, it is possible that quantum entanglement will translate into FTL
communications that can be used to replace everything we know, but that's rather
unlikely for at least a LONG time.
David Lang
> Alex
>
>
>> The laser communication system is about *40% faster* than fiber due to the
>> speed of light in vacuum
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>^1
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>.
>> The number of laser transponders in a second-generation Starlink satellite
>> is not mentioned in the information I found. However, it is worth noting
>> that the second-generation Starlink satellites are expected to be
>> significantly more capable than their predecessors
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>^1
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>.
>> They will be larger and much faster, with a capacity of up to *80 Gbps per
>> satellite*, compared to *18 Gbps* in the current version
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>^1
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>.
>> The proposed Starlink Gen2 constellation, consisting of approximately
>> 30,000 satellites, would have a total instantaneous bandwidth of at least
>> *500 terabits per second (Tbps) over land*, which is around 1800 Tbps
>> including ocean coverage
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>^1
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>.
>>
>> Please note that the information I provided is based on available sources
>> and may not cover all the details about the second-generation Starlink
>> satellites. For more specific information, it is recommended to refer to
>> official sources or SpaceX’s announcements.
>>
>> Is there anything else I can help you with? 😊
>>
>> Learn more:
>> 1. nextbigfuture.com
>> <https://www.nextbigfuture.com/2021/09/version-2-starlink-with-lasers-and-gen-2-spacex-starlink-bigger-and-faster.html>
>> 2. arstechnica.com
>> <https://arstechnica.com/information-technology/2021/01/spacex-adds-laser-links-to-starlink-satellites-to-serve-earths-polar-areas/>
>> 3. spaceflightnow.com
>> <https://spaceflightnow.com/2021/09/14/spacex-launches-first-full-batch-of-laser-equipped-starlink-satellites/>— see
>> less
>>
>> " *(End of BING Response)*
>>
>> Hesham
>>
>>
>>
>> On Sat, Sep 23, 2023, 2:55 PM Larry Press via Starlink
>> <starlink at lists.bufferbloat.net> wrote:
>>
>> In his first Starlink simulation, Mark Hadley assumed five
>> transponders per satellite -- Two in-plane, two adjacent, and one
>> crossing:
>> https://www.youtube.com/watch?v=3479tkagiNo&list=PLrRMhEONgz06oMXQOljB5BoZxZw6cShLN&index=3
>> <https://www.youtube.com/watch?v=3479tkagiNo&list=PLrRMhEONgz06oMXQOljB5BoZxZw6cShLN&index=3>
>>
>> In his next Starlink simulation, Mark Hadley assumed four:
>> https://www.youtube.com/watch?v=QEIUdMiColU&list=PLrRMhEONgz06oMXQOljB5BoZxZw6cShLN&index=2
>> <https://www.youtube.com/watch?v=QEIUdMiColU&list=PLrRMhEONgz06oMXQOljB5BoZxZw6cShLN&index=2>
>>
>> I guess he assumed the relative velocities were too high for the
>> crossing connection.
>>
>> I asked Bard "How many laser transponders are in a
>> second-generation Starlink satellite?" and it said "four."
>> I asked ChatGPT "How many laser transponders are in a
>> second-generation Starlink satellite?" and it said it did not know.
>> I asked Bard again and the second time it said it did not know.
>> When I pointed out that it had told me "four" the first time I
>> asked, Bard apologized for its previous answer.
>>
>> I remain an "AI" skeptic:
>> https://circleid.com/posts/20230721-google-bard-fails-to-answer-satellite-internet-questions
>>
>> *From:* Starlink <starlink-bounces at lists.bufferbloat.net> on
>> behalf of David Lang via Starlink <starlink at lists.bufferbloat.net>
>> *Sent:* Friday, September 22, 2023 1:41 AM
>> *To:* Alexandre Petrescu <alexandre.petrescu at gmail.com>
>> *Cc:* starlink at lists.bufferbloat.net <starlink at lists.bufferbloat.net>
>> *Subject:* Re: [Starlink] APNIC56 last week
>> I believe that I read that STarlink has 5 lasers per sat. but
>> whatever the
>> number, it's a tiny number compared to the number of satellites
>> that they have
>> up there.
>>
>> As you are looking at 'trains', check their altitude. They aren't
>> going to
>> shuffle sats around much, it's expensive in terms of fuel and they
>> are only
>> allowed to provide service when they are in their proper orbits.
>>
>> We know the lasers are in operation as they are providing service
>> to places more
>> than one sat hop away from ground stations. We also know they have
>> a lot of
>> ground stations around to share the load.
>>
>> We have almost no details on the specific modules they are using,
>> and none on
>> what routing they are using.
>>
>> David Lang
>>
>>
>> On Fri, 22 Sep 2023,
>> Alexandre Petrescu via Starlink wrote:
>>
>> > Date: Fri, 22 Sep 2023 10:26:26 +0200
>> > From: Alexandre Petrescu via Starlink
>> <starlink at lists.bufferbloat.net>
>> > Reply-To: Alexandre Petrescu <alexandre.petrescu at gmail.com>
>> > To: starlink at lists.bufferbloat.net
>> > Subject: Re: [Starlink] APNIC56 last week
>> >
>> >
>> > Le 21/09/2023 à 21:05, Inemesit Affia via Starlink a écrit :
>> >> Not going to go into details but lasers have been identified in
>> photos
>> >> of the sats and one of the component suppliers is known. (The
>> scale is
>> >> novel, not the tech, demisabiliy is new though)
>> >
>> > 4 or 2 lasers on each sat (N-S, E-W) is potentially a very
>> different
>> > matter from an IP routing standpoint. It still is a reduced set of
>> > variables, for a routing protocol (it is not like there being an
>> > arbitrary number of IP interfaces, it's just 2 or 4).
>> >
>> > For component manufacturers: yes, I heard about a few
>> manufacturers of
>> > such equipment for laser comms for LEO sats, experimented.
>> There is
>> > public information about a few of them. I dont know which is
>> considered
>> > by starlink, but there is not my worry. There is also a difference
>> > between laser links between sats on different orbit altitudes (e.g.
>> > laser for ISL for GEO to MEO) and lasers between sats on a same
>> orbit
>> > altitude, or on a same orbit. It's three different things, with
>> > different sets of requirements: focusing, power levels, distance
>> ranges.
>> >
>> > At the lowest limit (cheapest, less powerful, less range
>> distance), I
>> > suppose it is possible to use simply LiFi optical links (a sort
>> of WiFi
>> > but with light). If so, then it is very easy to have IP on it.
>> >
>> > There is also an 'optical' spec that was circulated here on this
>> list
>> >
>> (https://urldefense.com/v3/__https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf__;!!P7nkOOY!pso4rogBStK7jR7pEg21ACCfJyL_ZCltZip5K7pxmJhmaSKfOY1RgwXzW4EtPOvEhS9XoLRaKS8QbVoEgYhXDWmzfQ$
>> ),
>> > although it seemed to me to figure on kepler's website, not on
>> > starlink's. In that spec, it is said Ethernet, among other
>> things. On
>> > Ethernet, IP can run easily.
>> >
>> >>
>> >> Starlink can't deliver to Antarctica or Northern parts of Alaska,
>> >> Ascension Island, Diego Garcia, Easter Island, Vanuatu, Iran
>> without
>> >> ISL's etc
>> >
>> > I'll have to look where these places are.
>> >
>> > When looking at starlink satellites I often see trains forming and
>> > lasting for a while. Someone said these sats are like that
>> (trains)
>> > prior to be put on a more evenly distanced, in-orbit; but some time
>> > passed, and they continue this kind of behaviour: form denser
>> trains,
>> > then distance more evenly, and back again. So I am not sure these
>> > 'trains' are ephemeral. They seem to be in such 'train'
>> structure while
>> > above some particular continents or areas, but not sure. It
>> takes a lot
>> > of time to make a meaning of it.
>> >
>> > Also, now here are at least two kinds of starlink subscription
>> plans:
>> > 40EUR/month and 287EUR/month, for fixed vs mobile.
>> >
>> >>
>> >> North South links seem to work but not East West (if they exist)
>> >
>> > Yes, good question. It makes a lot of difference whether there
>> are 2 or
>> > 4 laser links on each sat. It also makes a lot of difference if
>> trying
>> > to make IP routing work there (assuming there could be 2 or 4 IP
>> > interfaces for lasers).
>> >
>> > This (number of ISL links on a starlink sat) can have an impact
>> on how
>> > people show LEO satellite topologies in Internet Drafts at IETF.
>> >
>> > Alex
>> >
>> >>
>> >> On Thu, Sep 21, 2023, 2:20 PM Alexandre Petrescu via Starlink
>> >> <starlink at lists.bufferbloat.net> wrote:
>> >>
>> >>
>> >> Le 19/09/2023 à 06:39, Ulrich Speidel via Starlink a écrit :
>> >> > FWIW, I gave a talk about Starlink - insights from a year
>> in -
>> >> at last
>> >> > week's APNIC56 conference in Kyoto:
>> >> >
>> >> >
>> https://urldefense.com/v3/__https://conference.apnic.net/56/program/program/*/day/6/technical-2/__;Iw!!P7nkOOY!pso4rogBStK7jR7pEg21ACCfJyL_ZCltZip5K7pxmJhmaSKfOY1RgwXzW4EtPOvEhS9XoLRaKS8QbVoEgYjUChNXHQ$
>>
>> >>
>> >>
>> >> Thanks for the presentation.
>> >>
>> >> I would like to ask what do you mean by "Method #2: "space
>> >> lasers""and
>> >> "Not all Starlink satellites have
>> >> lasers" on slide 5?
>> >>
>> >> It seems to be saying there is inter-satellite
>> communications. The
>> >> need
>> >> of that seems to stem from the lack of ground 'teleport'
>> that is
>> >> necessary for DISHY-SAT-Internet communications, so a
>> SAT-to-SAT
>> >> communication is apparently used with lasers. I can agree with
>> >> the need.
>> >>
>> >> What standard is used for these lasers?
>> >>
>> >> Is this ISL communicaiton within the starlink constellation a
>> >> supposition or a sure thing?
>> >>
>> >> Other presentations of starlink mentioned on this list dont
>> talk
>> >> about
>> >> this lasers between sats (dont show lasers on the sats),
>> but kepler
>> >> talks about optical links, and also there is talk about
>> ISOC LEO
>> >> Internet about such 'lasers from space'.
>> >>
>> >> (I must say that I thought previously that there were only
>> 2 or 3
>> >> ground
>> >> teleports overall in EU and USA, but I see now there is a
>> teleport
>> >> in NZ
>> >> too).
>> >>
>> >> (for price comparison: it is said 100USD monthly, but in
>> France right
>> >> now the monthly subscription is at around 40 Euros; this
>> competes
>> >> very
>> >> advantageously to other satcoms ISPs for rural areas
>> non-covered
>> >> by 5G;
>> >> the cellular monthly subscriptions are still much more
>> advantageous,
>> >> where there is 5G, of course).
>> >>
>> >> Alex
>> >>
>> >> >
>> >> > Also well worth looking at is Geoff Huston's excellent
>> piece on the
>> >> > foreseeable demise of TCP in favour of QUIC in the same
>> session.
>> >> One
>> >> > of Geoff's main arguments is that the Internet is
>> becoming local,
>> >> > i.e., most traffic goes between a CDN server and you, and
>> most
>> >> data is
>> >> > becoming proprietary to the application owner, meaning it
>> suits the
>> >> > Googles and Facebooks of this world very well not to be using
>> >> TCP for
>> >> > its transport, but rather pull the transport specifics
>> into the
>> >> > application layer where the have full control.
>> >> >
>> >> > Food for thought, especially since LEO networks are a
>> >> particularly bad
>> >> > place to put local content caches, since the concept of
>> what's
>> >> "local"
>> >> > in a LEO network changes constantly, at around 20,000
>> miles an
>> >> hour or
>> >> > so. Spoke to a Rwandan colleague who installs Starlink
>> there and
>> >> sees
>> >> > all traffic to anywhere go via the US with RTTs of nearly 2
>> >> seconds,
>> >> > even if the Rwandan user is trying to access a Rwandan
>> service.
>> >> >
>> >> > About to hop onto a plane (ZK-NZJ) tonight with free WiFi
>> (Ka band
>> >> > GEO) enroute to Auckland in the hope of getting a better
>> experience
>> >> > than last time when the system seemed to run out of IP
>> addresses on
>> >> > its DHCP.
>> >> >
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>> >>
>> >>
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