[atlas] Satellite based "last mile" and Atlas probes

As best I can determine the 2nd and 3rd hops are topologically very close
to the major IX points in Seattle. Based on the geographic location of my
probe and starlink terminal, its traffic goes up to space and back down
again to 1 of 3 possible starlink earth stations in Washington state.

These earth stations are known to be located at either the Starlink offices
in Redmond, WA, there is one site colocated with a Level3/Centurylink/Lumen
DWDM site slightly east of Seattle, and another which is at a commercial
teleport in the north-central part of the state.

RTT ICMP ping times to things in Seattle are a combination of two round
trips through space, plus modem framing/encoding/FEC, and terrestrial
latency from one of those earth stations to the downtown Seattle
destination and back. For instance to the anycase instances of a nameserver
that I know to be physically located at one of Seattle's main carrier
hotels.



On Fri, Apr 23, 2021 at 3:22 AM Ponikierski, Grzegorz via ripe-atlas <
ripe-atlas at ripe.net> wrote:

> Malte Appel already partially responded to you questions. I will try to
> provide more details.
>
>
>
> Each probe has build-in measurements for 1st and 2nd hop. For your probe
> it is:
>
>    - nice view https://atlas.ripe.net/probes/1001821/#tab-builtins
>    - 1st hop
>    https://atlas.ripe.net/api/v2/measurements/1/results/?probe_ids=1001821&start=1619136000&stop=1619222399&format=json
>    - 2nd hop
>    https://atlas.ripe.net/api/v2/measurements/2/results/?probe_ids=1001821&start=1619136000&stop=1619222399&format=json
>
>
>
> If you take your probe as an example you will notice that your first hop
> is your local router (Starlink dish?) and it has RTT <1ms. It's your 2nd
> hop which can indicate what RTT is generated by Starlink satellite
> connection (RTT Median Average ~30ms). I'm curious where exactly is located
> this 2nd hop :)
>
>
>
> Regards,
>
> Grzegorz
>
>
>
> *From: *Ray Bellis <ray at isc.org>
> *Date: *Friday 2021-04-23 at 10:44
> *To: *"ripe-atlas at ripe.net" <ripe-atlas at ripe.net>
> *Subject: *Re: [atlas] Satellite based "last mile" and Atlas probes
>
>
>
>
>
>
>
> On 22/04/2021 20:52, Ponikierski, Grzegorz via ripe-atlas wrote:
>
> Checking
>
> first hop can be tricky because this first hop can be local router with
>
> RTT <1ms and second hop can indicate that we are on satellite
>
> connectivity. For that API for sure API must be used. Here is the full
>
> list of build in measurements:
>
>
> https://urldefense.com/v3/__https://beta-docs.atlas.ripe.net/built-in/reference.html*traceroute-5-000-6-999__;Iw!!GjvTz_vk!CGnJSJwFwnAeSTFJcu_wN5qF5pxMnHYnUY2rcHz_afOJoH0Tp49DDDQm0TvPlSQ$
> <https://urldefense.com/v3/__https:/beta-docs.atlas.ripe.net/built-in/reference.html*traceroute-5-000-6-999__;Iw!!GjvTz_vk!CGnJSJwFwnAeSTFJcu_wN5qF5pxMnHYnUY2rcHz_afOJoH0Tp49DDDQm0TvPlSQ$>
>
> <
> https://urldefense.com/v3/__https://beta-docs.atlas.ripe.net/built-in/reference.html*traceroute-5-000-6-999__;Iw!!GjvTz_vk!CGnJSJwFwnAeSTFJcu_wN5qF5pxMnHYnUY2rcHz_afOJoH0Tp49DDDQm0TvPlSQ$
> <https://urldefense.com/v3/__https:/beta-docs.atlas.ripe.net/built-in/reference.html*traceroute-5-000-6-999__;Iw!!GjvTz_vk!CGnJSJwFwnAeSTFJcu_wN5qF5pxMnHYnUY2rcHz_afOJoH0Tp49DDDQm0TvPlSQ$>
> >
>
> + build in ping tests for 1^st and 2^nd hop are respectively measurement
>
> #1 and #2.
>
>
>
> Can you please elaborate on this?
>
>
>
> I have a separate need (relating to an ICANN RSSAC WG) to be able to
>
> detect high latency last mile hops but I could not identify the specific
>
> "built-in ping tests for 1st and 2nd hop" that you described.
>
>
>
> Were you perhaps suggesting that it was actually just the first couple
>
> of rows of data from the built-in *traceroute* tests that hold this data?
>
>
>
> thanks,
>
>
>
> Ray
>
>
>
>
>
>
>
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