* [Starlink] mems optical switching
@ 2023-03-18 22:19 Dave Taht
2023-03-19 12:58 ` Michael Richardson
2023-03-19 14:16 ` Brandon Butterworth
0 siblings, 2 replies; 8+ messages in thread
From: Dave Taht @ 2023-03-18 22:19 UTC (permalink / raw)
To: Dave Taht via Starlink
I think, in general, we have gathered here quite a few folk that are
interested in new technology, and the list
does veer away from starlink issues more often than not. Today, this
about google's mems switching tech hit,
and I keep wondering where else it could be applied.
https://www.semianalysis.com/p/google-apollo-the-3-billion-game
--
Come Heckle Mar 6-9 at: https://www.understandinglatency.com/
Dave Täht CEO, TekLibre, LLC
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Starlink] mems optical switching
2023-03-18 22:19 [Starlink] mems optical switching Dave Taht
@ 2023-03-19 12:58 ` Michael Richardson
2023-03-19 14:16 ` Brandon Butterworth
1 sibling, 0 replies; 8+ messages in thread
From: Michael Richardson @ 2023-03-19 12:58 UTC (permalink / raw)
To: Dave Taht via Starlink
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Dave Taht via Starlink <starlink@lists.bufferbloat.net> wrote:
> I think, in general, we have gathered here quite a few folk that are
> interested in new technology, and the list
> does veer away from starlink issues more often than not. Today, this
> about google's mems switching tech hit,
> and I keep wondering where else it could be applied.
> https://www.semianalysis.com/p/google-apollo-the-3-billion-game
An interesting read.
Starlink content: could they avoid latency and power consumption by using
optical switching in the satellites. I suspect it's irrelevant, because the
satellites don't have more than about four lasers. (I think I heard four)
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Starlink] mems optical switching
2023-03-18 22:19 [Starlink] mems optical switching Dave Taht
2023-03-19 12:58 ` Michael Richardson
@ 2023-03-19 14:16 ` Brandon Butterworth
2023-03-19 14:33 ` Christian von der Ropp
1 sibling, 1 reply; 8+ messages in thread
From: Brandon Butterworth @ 2023-03-19 14:16 UTC (permalink / raw)
To: Dave Taht; +Cc: Dave Taht via Starlink, brandon
On Sat Mar 18, 2023 at 03:19:49PM -0700, Dave Taht via Starlink wrote:
> Today, this about google's mems switching tech hit,
They've been talking about it since last year, seems to have got
a hype bump recently.
Who expected circuit switching to make a comeback?
> I keep wondering where else it could be applied.
They've been used for a long time, eg almost 20 years ago -
https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf
There is a goal of optical packet switching, until then you're
limited to where there are limited flows of long enough duration
to make the change from packet to circuit switching viable. So mostly
automated testing.
I've dabbled with the idea in an archive use case where very few of
a large set of storage nodes need to connect to a moderate number
of servers. For some cases we could have zero switches. The goal was
a mostly dark infrastructure and many 1000s of storage nodes,
removing the switches saves a lot of power.
Commercial optical switches are expensive so I was looking at
making an optical strowger as I wanted a high fan out not
large n^2.
In the mobile world they are looking at doing flexible bandwidth
per node with coherent optics over gpon fibre plant, allocating
variable amounts of spectrum to each, which could be adapted to a
similar circuit model. It'd be no use to google as they want the
full bandwidth between each node but as dwdm coherent optic costs
come down you could imagine doing the same with a full channel
between each pair, so like a conventional WSS but cheaper. If it
wasn't for the optics cost I suspect they'd have done that reducing
switching time to a channel change.
brandon
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Starlink] mems optical switching
2023-03-19 14:16 ` Brandon Butterworth
@ 2023-03-19 14:33 ` Christian von der Ropp
2023-03-20 11:32 ` Dave Taht
0 siblings, 1 reply; 8+ messages in thread
From: Christian von der Ropp @ 2023-03-19 14:33 UTC (permalink / raw)
To: starlink
All-optical switching could greatly reduce complexity and power
consumption on the satellites at the cost of flexibility. Up to 44
satellites in an orbital plane would use individual wavelengths which
would be passed on transparently down the daisy chain and only
satellites in range of gateways would convert the optical signals back
into electrical ones, and send them down to earth while they pass a
gateway. This would result in relatively short duty cycles, hence less
power draw per orbit and less heat dissipation issues.
Actually I've been suspecting that the SDA targets all-optical switching
for the Transport Layer constellation as I don't seen any other
immediate reason for the requirement of their OISL standard to require
wavelength switching within the ITU channel grid for LCTs (see p. 18 of
the OISL 3.0:
https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf)
As a matter of fact tuneable wavelenghts were already required in the
draft version of the OISL standard published in April 2020:
https://twitter.com/Megaconstellati/status/1310336728595562499
-Christian
Am 19.03.2023 um 16:16 schrieb Brandon Butterworth via Starlink:
> On Sat Mar 18, 2023 at 03:19:49PM -0700, Dave Taht via Starlink wrote:
>> Today, this about google's mems switching tech hit,
> They've been talking about it since last year, seems to have got
> a hype bump recently.
>
> Who expected circuit switching to make a comeback?
>
>> I keep wondering where else it could be applied.
> They've been used for a long time, eg almost 20 years ago -
> https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf
>
> There is a goal of optical packet switching, until then you're
> limited to where there are limited flows of long enough duration
> to make the change from packet to circuit switching viable. So mostly
> automated testing.
>
> I've dabbled with the idea in an archive use case where very few of
> a large set of storage nodes need to connect to a moderate number
> of servers. For some cases we could have zero switches. The goal was
> a mostly dark infrastructure and many 1000s of storage nodes,
> removing the switches saves a lot of power.
>
> Commercial optical switches are expensive so I was looking at
> making an optical strowger as I wanted a high fan out not
> large n^2.
>
> In the mobile world they are looking at doing flexible bandwidth
> per node with coherent optics over gpon fibre plant, allocating
> variable amounts of spectrum to each, which could be adapted to a
> similar circuit model. It'd be no use to google as they want the
> full bandwidth between each node but as dwdm coherent optic costs
> come down you could imagine doing the same with a full channel
> between each pair, so like a conventional WSS but cheaper. If it
> wasn't for the optics cost I suspect they'd have done that reducing
> switching time to a channel change.
>
> brandon
> _______________________________________________
> Starlink mailing list
> Starlink@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Starlink] mems optical switching
2023-03-19 14:33 ` Christian von der Ropp
@ 2023-03-20 11:32 ` Dave Taht
2023-03-20 11:42 ` David Lang
2023-03-20 11:46 ` Mike Puchol
0 siblings, 2 replies; 8+ messages in thread
From: Dave Taht @ 2023-03-20 11:32 UTC (permalink / raw)
To: Christian von der Ropp; +Cc: starlink
We haven't heard much about the starlink ISL links lately. Any sign
they are working anywhere yet?
On Sun, Mar 19, 2023 at 7:33 AM Christian von der Ropp via Starlink
<starlink@lists.bufferbloat.net> wrote:
>
> All-optical switching could greatly reduce complexity and power
> consumption on the satellites at the cost of flexibility. Up to 44
> satellites in an orbital plane would use individual wavelengths which
> would be passed on transparently down the daisy chain and only
> satellites in range of gateways would convert the optical signals back
> into electrical ones, and send them down to earth while they pass a
> gateway. This would result in relatively short duty cycles, hence less
> power draw per orbit and less heat dissipation issues.
>
> Actually I've been suspecting that the SDA targets all-optical switching
> for the Transport Layer constellation as I don't seen any other
> immediate reason for the requirement of their OISL standard to require
> wavelength switching within the ITU channel grid for LCTs (see p. 18 of
> the OISL 3.0:
> https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf)
>
> As a matter of fact tuneable wavelenghts were already required in the
> draft version of the OISL standard published in April 2020:
> https://twitter.com/Megaconstellati/status/1310336728595562499
>
> -Christian
>
> Am 19.03.2023 um 16:16 schrieb Brandon Butterworth via Starlink:
> > On Sat Mar 18, 2023 at 03:19:49PM -0700, Dave Taht via Starlink wrote:
> >> Today, this about google's mems switching tech hit,
> > They've been talking about it since last year, seems to have got
> > a hype bump recently.
> >
> > Who expected circuit switching to make a comeback?
> >
> >> I keep wondering where else it could be applied.
> > They've been used for a long time, eg almost 20 years ago -
> > https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf
> >
> > There is a goal of optical packet switching, until then you're
> > limited to where there are limited flows of long enough duration
> > to make the change from packet to circuit switching viable. So mostly
> > automated testing.
> >
> > I've dabbled with the idea in an archive use case where very few of
> > a large set of storage nodes need to connect to a moderate number
> > of servers. For some cases we could have zero switches. The goal was
> > a mostly dark infrastructure and many 1000s of storage nodes,
> > removing the switches saves a lot of power.
> >
> > Commercial optical switches are expensive so I was looking at
> > making an optical strowger as I wanted a high fan out not
> > large n^2.
> >
> > In the mobile world they are looking at doing flexible bandwidth
> > per node with coherent optics over gpon fibre plant, allocating
> > variable amounts of spectrum to each, which could be adapted to a
> > similar circuit model. It'd be no use to google as they want the
> > full bandwidth between each node but as dwdm coherent optic costs
> > come down you could imagine doing the same with a full channel
> > between each pair, so like a conventional WSS but cheaper. If it
> > wasn't for the optics cost I suspect they'd have done that reducing
> > switching time to a channel change.
> >
> > brandon
> > _______________________________________________
> > 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
--
Come Heckle Mar 6-9 at: https://www.understandinglatency.com/
Dave Täht CEO, TekLibre, LLC
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Starlink] mems optical switching
2023-03-20 11:32 ` Dave Taht
@ 2023-03-20 11:42 ` David Lang
2023-03-20 11:46 ` Mike Puchol
1 sibling, 0 replies; 8+ messages in thread
From: David Lang @ 2023-03-20 11:42 UTC (permalink / raw)
To: Dave Taht; +Cc: Christian von der Ropp, starlink
[-- Attachment #1: Type: text/plain, Size: 4510 bytes --]
Their coverage of the poles and oceans is growing outside of the 'bent pipe'
model, so I think that's proof that they are working.
I am in southern california and commonly go out a gateway in vancouver BC, I
think that's more than a simple bent-pipe hop away.
David Lang
On Mon, 20 Mar 2023, Dave Taht via Starlink wrote:
> Date: Mon, 20 Mar 2023 04:32:19 -0700
> From: Dave Taht via Starlink <starlink@lists.bufferbloat.net>
> Reply-To: Dave Taht <dave.taht@gmail.com>
> To: Christian von der Ropp <cvdr@vdr.net>
> Cc: starlink@lists.bufferbloat.net
> Subject: Re: [Starlink] mems optical switching
>
> We haven't heard much about the starlink ISL links lately. Any sign
> they are working anywhere yet?
>
> On Sun, Mar 19, 2023 at 7:33 AM Christian von der Ropp via Starlink
> <starlink@lists.bufferbloat.net> wrote:
>>
>> All-optical switching could greatly reduce complexity and power
>> consumption on the satellites at the cost of flexibility. Up to 44
>> satellites in an orbital plane would use individual wavelengths which
>> would be passed on transparently down the daisy chain and only
>> satellites in range of gateways would convert the optical signals back
>> into electrical ones, and send them down to earth while they pass a
>> gateway. This would result in relatively short duty cycles, hence less
>> power draw per orbit and less heat dissipation issues.
>>
>> Actually I've been suspecting that the SDA targets all-optical switching
>> for the Transport Layer constellation as I don't seen any other
>> immediate reason for the requirement of their OISL standard to require
>> wavelength switching within the ITU channel grid for LCTs (see p. 18 of
>> the OISL 3.0:
>> https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf)
>>
>> As a matter of fact tuneable wavelenghts were already required in the
>> draft version of the OISL standard published in April 2020:
>> https://twitter.com/Megaconstellati/status/1310336728595562499
>>
>> -Christian
>>
>> Am 19.03.2023 um 16:16 schrieb Brandon Butterworth via Starlink:
>> > On Sat Mar 18, 2023 at 03:19:49PM -0700, Dave Taht via Starlink wrote:
>> >> Today, this about google's mems switching tech hit,
>> > They've been talking about it since last year, seems to have got
>> > a hype bump recently.
>> >
>> > Who expected circuit switching to make a comeback?
>> >
>> >> I keep wondering where else it could be applied.
>> > They've been used for a long time, eg almost 20 years ago -
>> > https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf
>> >
>> > There is a goal of optical packet switching, until then you're
>> > limited to where there are limited flows of long enough duration
>> > to make the change from packet to circuit switching viable. So mostly
>> > automated testing.
>> >
>> > I've dabbled with the idea in an archive use case where very few of
>> > a large set of storage nodes need to connect to a moderate number
>> > of servers. For some cases we could have zero switches. The goal was
>> > a mostly dark infrastructure and many 1000s of storage nodes,
>> > removing the switches saves a lot of power.
>> >
>> > Commercial optical switches are expensive so I was looking at
>> > making an optical strowger as I wanted a high fan out not
>> > large n^2.
>> >
>> > In the mobile world they are looking at doing flexible bandwidth
>> > per node with coherent optics over gpon fibre plant, allocating
>> > variable amounts of spectrum to each, which could be adapted to a
>> > similar circuit model. It'd be no use to google as they want the
>> > full bandwidth between each node but as dwdm coherent optic costs
>> > come down you could imagine doing the same with a full channel
>> > between each pair, so like a conventional WSS but cheaper. If it
>> > wasn't for the optics cost I suspect they'd have done that reducing
>> > switching time to a channel change.
>> >
>> > brandon
>> > _______________________________________________
>> > 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
>
>
>
> --
> Come Heckle Mar 6-9 at: https://www.understandinglatency.com/
> Dave Täht CEO, TekLibre, LLC
> _______________________________________________
> Starlink mailing list
> Starlink@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Starlink] mems optical switching
2023-03-20 11:32 ` Dave Taht
2023-03-20 11:42 ` David Lang
@ 2023-03-20 11:46 ` Mike Puchol
2023-03-20 18:55 ` Ulrich Speidel
1 sibling, 1 reply; 8+ messages in thread
From: Mike Puchol @ 2023-03-20 11:46 UTC (permalink / raw)
To: Dave Taht, starlink
[-- Attachment #1: Type: text/plain, Size: 5145 bytes --]
I tested them in the middle of nowhere (literally) and it worked, no gateways anywhere even close. Latencies varied between 20-30ms and up to 400ms (to the POP), and there were occasional outages.
What was fascinating was that I could predict when an outage would take place by watching starlink.sx and seeing that the ISL-linked satellites would dissapear from view with no others to take over, and also predicting when I'd have service again by watching the next ISL-linked sat approach the field-of-view.
The other test I did was, while watching the tracker and the azimuth to the satellite, place myself at the right position between the antenna and the satellite, and confirm that the link would drop.
All of the above was possible because a) there weren't that many ISL satellites in orbit at the time, and b) the density of satellites in the region I was testing was low, so only 1-2 satellites could be serving my location at a time, making tests easier.
Best,
Mike
On Mar 20, 2023 at 12:32 +0100, Dave Taht via Starlink <starlink@lists.bufferbloat.net>, wrote:
> We haven't heard much about the starlink ISL links lately. Any sign
> they are working anywhere yet?
>
> On Sun, Mar 19, 2023 at 7:33 AM Christian von der Ropp via Starlink
> <starlink@lists.bufferbloat.net> wrote:
> >
> > All-optical switching could greatly reduce complexity and power
> > consumption on the satellites at the cost of flexibility. Up to 44
> > satellites in an orbital plane would use individual wavelengths which
> > would be passed on transparently down the daisy chain and only
> > satellites in range of gateways would convert the optical signals back
> > into electrical ones, and send them down to earth while they pass a
> > gateway. This would result in relatively short duty cycles, hence less
> > power draw per orbit and less heat dissipation issues.
> >
> > Actually I've been suspecting that the SDA targets all-optical switching
> > for the Transport Layer constellation as I don't seen any other
> > immediate reason for the requirement of their OISL standard to require
> > wavelength switching within the ITU channel grid for LCTs (see p. 18 of
> > the OISL 3.0:
> > https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf)
> >
> > As a matter of fact tuneable wavelenghts were already required in the
> > draft version of the OISL standard published in April 2020:
> > https://twitter.com/Megaconstellati/status/1310336728595562499
> >
> > -Christian
> >
> > Am 19.03.2023 um 16:16 schrieb Brandon Butterworth via Starlink:
> > > On Sat Mar 18, 2023 at 03:19:49PM -0700, Dave Taht via Starlink wrote:
> > > > Today, this about google's mems switching tech hit,
> > > They've been talking about it since last year, seems to have got
> > > a hype bump recently.
> > >
> > > Who expected circuit switching to make a comeback?
> > >
> > > > I keep wondering where else it could be applied.
> > > They've been used for a long time, eg almost 20 years ago -
> > > https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf
> > >
> > > There is a goal of optical packet switching, until then you're
> > > limited to where there are limited flows of long enough duration
> > > to make the change from packet to circuit switching viable. So mostly
> > > automated testing.
> > >
> > > I've dabbled with the idea in an archive use case where very few of
> > > a large set of storage nodes need to connect to a moderate number
> > > of servers. For some cases we could have zero switches. The goal was
> > > a mostly dark infrastructure and many 1000s of storage nodes,
> > > removing the switches saves a lot of power.
> > >
> > > Commercial optical switches are expensive so I was looking at
> > > making an optical strowger as I wanted a high fan out not
> > > large n^2.
> > >
> > > In the mobile world they are looking at doing flexible bandwidth
> > > per node with coherent optics over gpon fibre plant, allocating
> > > variable amounts of spectrum to each, which could be adapted to a
> > > similar circuit model. It'd be no use to google as they want the
> > > full bandwidth between each node but as dwdm coherent optic costs
> > > come down you could imagine doing the same with a full channel
> > > between each pair, so like a conventional WSS but cheaper. If it
> > > wasn't for the optics cost I suspect they'd have done that reducing
> > > switching time to a channel change.
> > >
> > > brandon
> > > _______________________________________________
> > > 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
>
>
>
> --
> Come Heckle Mar 6-9 at: https://www.understandinglatency.com/
> Dave Täht CEO, TekLibre, LLC
> _______________________________________________
> Starlink mailing list
> Starlink@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Starlink] mems optical switching
2023-03-20 11:46 ` Mike Puchol
@ 2023-03-20 18:55 ` Ulrich Speidel
0 siblings, 0 replies; 8+ messages in thread
From: Ulrich Speidel @ 2023-03-20 18:55 UTC (permalink / raw)
To: starlink
[-- Attachment #1: Type: text/plain, Size: 7635 bytes --]
Not so fast! A number of issues here, and one of them is that the
question itself is unclear. There are several levels of "working":
* A satellite forwarding uplink traffic to an adjacent peer within the
same orbital plane for downlink.
o Dto for cross-plane
* A satellite forwarding incoming laser link traffic to another
satellite in the same orbital plane.
o Dto for cross-plane
* Routing to select destinations only.
* Routing to everywhere.
* Doing so efficiently globally under load.
I'm pretty sure that they are managing somewhere around the first 3-4
major bullet points by now, with probably some outages (I note that
Starlink now advertises global maritime coverage, at a price around 10
times that of a land-based subscription). But the last point is where it
truly gets hard.
The other thing worth remembering is that distance isn't necessarily a
good indicator - it depends on where that distance accrues. Southern
California to southern BC is around 2000 km, and the zone around the
US-Canada border is where satellite density is highest - and capacity
attracts in Starlink. Note also that gateways are generally in spots
where there is little obstruction in terms of elevation, so in the case
of Vancouver BC can probably serve birds that are just a few degrees
over the horizon (which also helps keeping the beam out of geostationary
trouble). Read: a lot stays bent pipe.
On 21/03/2023 12:46 am, Mike Puchol via Starlink wrote:
> I tested them in the middle of nowhere (literally) and it worked, no
> gateways anywhere even close. Latencies varied between 20-30ms and up
> to 400ms (to the POP), and there were occasional outages.
>
> What was fascinating was that I could predict when an outage would
> take place by watching starlink.sx and seeing that the ISL-linked
> satellites would dissapear from view with no others to take over, and
> also predicting when I'd have service again by watching the next
> ISL-linked sat approach the field-of-view.
>
> The other test I did was, while watching the tracker and the azimuth
> to the satellite, place myself at the right position between the
> antenna and the satellite, and confirm that the link would drop.
>
> All of the above was possible because a) there weren't that many ISL
> satellites in orbit at the time, and b) the density of satellites in
> the region I was testing was low, so only 1-2 satellites could be
> serving my location at a time, making tests easier.
>
> Best,
>
> Mike
> On Mar 20, 2023 at 12:32 +0100, Dave Taht via Starlink
> <starlink@lists.bufferbloat.net>, wrote:
>> We haven't heard much about the starlink ISL links lately. Any sign
>> they are working anywhere yet?
>>
>> On Sun, Mar 19, 2023 at 7:33 AM Christian von der Ropp via Starlink
>> <starlink@lists.bufferbloat.net> wrote:
>>>
>>> All-optical switching could greatly reduce complexity and power
>>> consumption on the satellites at the cost of flexibility. Up to 44
>>> satellites in an orbital plane would use individual wavelengths which
>>> would be passed on transparently down the daisy chain and only
>>> satellites in range of gateways would convert the optical signals back
>>> into electrical ones, and send them down to earth while they pass a
>>> gateway. This would result in relatively short duty cycles, hence less
>>> power draw per orbit and less heat dissipation issues.
>>>
>>> Actually I've been suspecting that the SDA targets all-optical switching
>>> for the Transport Layer constellation as I don't seen any other
>>> immediate reason for the requirement of their OISL standard to require
>>> wavelength switching within the ITU channel grid for LCTs (see p. 18 of
>>> the OISL 3.0:
>>> https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf)
>>> <https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf)>
>>>
>>> As a matter of fact tuneable wavelenghts were already required in the
>>> draft version of the OISL standard published in April 2020:
>>> https://twitter.com/Megaconstellati/status/1310336728595562499
>>> <https://twitter.com/Megaconstellati/status/1310336728595562499>
>>>
>>> -Christian
>>>
>>> Am 19.03.2023 um 16:16 schrieb Brandon Butterworth via Starlink:
>>>> On Sat Mar 18, 2023 at 03:19:49PM -0700, Dave Taht via Starlink wrote:
>>>>> Today, this about google's mems switching tech hit,
>>>> They've been talking about it since last year, seems to have got
>>>> a hype bump recently.
>>>>
>>>> Who expected circuit switching to make a comeback?
>>>>
>>>>> I keep wondering where else it could be applied.
>>>> They've been used for a long time, eg almost 20 years ago -
>>>> https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf
>>>> <https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf>
>>>>
>>>> There is a goal of optical packet switching, until then you're
>>>> limited to where there are limited flows of long enough duration
>>>> to make the change from packet to circuit switching viable. So mostly
>>>> automated testing.
>>>>
>>>> I've dabbled with the idea in an archive use case where very few of
>>>> a large set of storage nodes need to connect to a moderate number
>>>> of servers. For some cases we could have zero switches. The goal was
>>>> a mostly dark infrastructure and many 1000s of storage nodes,
>>>> removing the switches saves a lot of power.
>>>>
>>>> Commercial optical switches are expensive so I was looking at
>>>> making an optical strowger as I wanted a high fan out not
>>>> large n^2.
>>>>
>>>> In the mobile world they are looking at doing flexible bandwidth
>>>> per node with coherent optics over gpon fibre plant, allocating
>>>> variable amounts of spectrum to each, which could be adapted to a
>>>> similar circuit model. It'd be no use to google as they want the
>>>> full bandwidth between each node but as dwdm coherent optic costs
>>>> come down you could imagine doing the same with a full channel
>>>> between each pair, so like a conventional WSS but cheaper. If it
>>>> wasn't for the optics cost I suspect they'd have done that reducing
>>>> switching time to a channel change.
>>>>
>>>> brandon
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>>>
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>>
>>
>>
>> --
>> Come Heckle Mar 6-9 at: https://www.understandinglatency.com/
>> <https://www.understandinglatency.com/>
>> Dave Täht CEO, TekLibre, LLC
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>
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--
****************************************************************
Dr. Ulrich Speidel
School of Computer Science
Room 303S.594 (City Campus)
The University of Auckland
u.speidel@auckland.ac.nz
http://www.cs.auckland.ac.nz/~ulrich/
****************************************************************
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2023-03-18 22:19 [Starlink] mems optical switching Dave Taht
2023-03-19 12:58 ` Michael Richardson
2023-03-19 14:16 ` Brandon Butterworth
2023-03-19 14:33 ` Christian von der Ropp
2023-03-20 11:32 ` Dave Taht
2023-03-20 11:42 ` David Lang
2023-03-20 11:46 ` Mike Puchol
2023-03-20 18:55 ` Ulrich Speidel
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