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<p>I think the blog used the data they collected from speedtest.net.
I conducted research on that topic. Ookla's speedtest is TCP based
(usually 4-6 concurrent TCP flows to a test server). Ookla
deployed over 12k test servers (many ISPs contributed to it). The
test used IP geolocation to pick a set of ten nearest servers
geographically and establish WebSocket to send "ping"s to test the
network latency. The test then chooses the server with the lowest
latency and send 10 more probes to test the RTTs. The "latency"
they referred should be the extract from the RTT tests.</p>
<p>I think it is a norm to have shared last mile and advertise the
"max" capacity, just like what cable providers did.</p>
<p>I remembered when they start launching the beta test. Only that
latitude range had continuous satellite coverage. I assume the
service outside that range would be unstable. But they have ground
station built out of that range already. So, they just need to
launch more SpaceX rockets...</p>
<p>For CDN, they signed agreements with Google (and Azure?) I expect
ground stations have direct interconnection with the cloud
providers for content. They can also have caches installed in the
ground station (e.g., netflix, youtube), similar to some ordinary
ISPs installed in-network caches in Central Offices. However, i
agree that they cannot do caching on the satellites, particularly
we have HTTPS :)<br>
</p>
<p>Ricky<br>
</p>
<div class="moz-cite-prefix">On 8/12/2021 3:34 PM, Ulrich Speidel
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:786faf6a-988d-ff29-42a6-44b508bf6625@cs.auckland.ac.nz">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<p>It always pains me to see "speed" tests like these, especially
if the methodology they've used isn't clear. My big gripes:</p>
<p>- I strongly suspect that the speed tests here (and in so many
other blogs/vlogs) are UDP-based, which doesn't tell me a thing
about how much TCP goodput I'll get over any of these links.<br>
- Latency is measured between end user and ... what? The
satellite gateway? Some imaginary fixed point on the Internet
that all our traffic has to to through? Or maybe just
speedtest.net's servers, whose locations possibly don't matter
one iota for my Internet performance?<br>
- If we reasonably assume that the capacity of a Starlink
satellite needs to be shared between its users, then few users /
satellite equates to a large share of the capacity. From
Starlink's front page: "Starlink is available to a limited
number of users per coverage area at this time." Guess what?
What we see here may not last, but it's sure great for
marketing.<br>
- Ever wondered why Starlink's bulk of beta users sits between
40-something and 50-something degrees of latitude? That's right,
because that's where you get the largest concentration of
satellites right now, which helps keep the number of users per
satellite down. Elsewhere? Tough luck.<br>
- At the other end of your terrestrial broadband connection
might be a few CDN servers, meaning you and your fellow
customers will only need to use the ISP's feed once for that
viral cat video everyone wants to watch. Starlink goes direct to
site, not to a local ISP. So if your ISP is in space and the
CDNs are on the ground, a thousand Starlink users on a satellite
wanting to watch the cat video will need to bring it across the
satellite a thousand times. Your terrestrial ISP (or even
sat-based ISP with a terrestrial network connecting end users)
only needs to do this once.</p>
<p>But big numbers always look great, don't they?</p>
On 13/08/2021 9:22 am, Darrell Budic wrote:<br>
<blockquote type="cite"
cite="mid:7AB190E6-A974-42A4-982F-5071CA45F31E@onholyground.com">
<a
href="https://www.speedtest.net/insights/blog/starlink-hughesnet-viasat-performance-q2-2021/"
class="" moz-do-not-send="true">https://www.speedtest.net/insights/blog/starlink-hughesnet-viasat-performance-q2-2021/</a>
<div class=""><br class="">
</div>
<div class="">Nothing we didn’t know, but interesting
comparisons between the 3 sat companies and fixed breadboard
around the world.</div>
<div class=""><br class="">
</div>
<div class="">Made me wonder if there’s anyone else contributing
to the speed tests in Iowa county, WI, looks a lot like my
averages there...</div>
<br>
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<pre class="moz-signature" cols="72">--
****************************************************************
Dr. Ulrich Speidel
School of Computer Science
Room 303S.594 (City Campus)
Ph: (+64-9)-373-7599 ext. 85282
The University of Auckland
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