Hi Dave,
you probably know already, but
mtr -ezb4 www.heise.de
will report compliant MPLS segments:
My traceroute [v0.95]
123-1234567.local (192.168.42.229) -> www.heise.de (193.99.144.85)
2023-08-30T21:39:48+0200
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host
Loss% Snt Last Avg Best Wrst StDev
1. AS??? 192.168.42.1 (192.168.42.1)
0.0% 1067 0.9 0.6 0.5 9.1 0.4
2. AS6805 loopback1.0003.acln.06.ham.de.net.telefonica.de (62.52.201.200)
0.0% 1067 12.3 22.5 9.9 172.7 17.5
3. AS6805 bundle-ether10.0002.dbrx.06.ham.de.net.telefonica.de (62.53.2.98)
0.7% 1067 12.4 12.0 10.3 16.5 0.7
4. AS6805 ae7-0.0001.corx.06.ham.de.net.telefonica.de (62.53.15.0)
0.0% 1067 18.7 19.2 17.2 48.9 2.4
[MPLS: Lbl 16624 TC 0 S 1 TTL 1]
5. AS6805 ae6-0.0002.corx.02.fra.de.net.telefonica.de (62.53.0.49)
0.0% 1067 41.6 19.6 17.2 51.6 3.9
[MPLS: Lbl 16624 TC 0 S 1 TTL 1]
6. AS6805 bundle-ether2.0001.cord.01.off.de.net.telefonica.de (62.53.0.199)
0.0% 1067 19.0 19.3 17.7 87.1 2.2
[MPLS: Lbl 16624 TC 0 S 1 TTL 1]
7. AS6805 bundle-ether1.0002.corp.01.off.de.net.telefonica.de (62.53.28.171)
0.0% 1067 22.9 19.2 17.5 29.7 0.9
8. AS??? ipv4.de-cix.fra.de.as12306.plusline.net (80.81.192.132)
0.0% 1066 18.5 19.7 18.2 93.0 2.5
9. AS12306 82.98.102.71 (82.98.102.71)
0.0% 1066 19.6 19.4 17.7 69.5 1.7
[MPLS: Lbl 24002 TC 0 S 1 TTL 1]
10. AS12306 82.98.102.23 (82.98.102.23)
0.0% 1066 17.8 19.8 17.4 197.7 9.9
11. AS12306 212.19.61.13 (212.19.61.13)
0.0% 1066 19.8 19.6 17.5 155.7 6.1
12. AS12306 www.heise.de (193.99.144.85)
0.1% 1066 19.6 19.1 17.6 63.7 1.5
Not that these do not already stick out as hops at different locations (here
Hamburg (ham), Frankfurt (fra) and Offenbach)) all with more or less identical
distance-independent RTTs.
Other than that quite intriguing puzzle, I wonder whether we could teach flent
to run a bidirectional traceroute/mtr as part of its measurements..?
Regards
Sebastian
> On Aug 30, 2023, at 20:07, Dave Taht via Starlink
> <starlink@lists.bufferbloat.net> wrote:
>
> In the attached 5 minute plot from a few days ago (I can supply the
> flent.gz files if anyone wants them), I see a puzzling spike at T+155s
> to nearly 90ms of baseline latency, then down to 20ms. No degree of
> orbital mechanics can apply to this change, even factoring in an over
> the horizon connection, routing packets on the ground through LA to
> seattle, and back, or using a couple ISLs, can make this add up for
> me. A combination of all that, kind of does make sense.
>
> The trace otherwise shows the sawtooth pattern of a single tcp flow ,
> a loss (sometimes catastrophic) at every downward bandwidth change.
>
> An assumption I have long been making is the latency staircase effect
> (see T+170) forward is achieving the best encoding rate at the
> distance then seen, the distance growing and the encoding rate falling
> in distinct steps, with a fixed amount of buffering, until finally
> that sat starts falling out of range, and it choses another at T+240s.
>
> But jeeze, a 70ms baseline latency swing? What gives? I imagine
> somehow correlating this with a mpls enabled traceroute might begin to
> make some sense of it, correlated by orbital positions....
>
>
> --
> Oct 30: https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
> Dave Täht CSO, LibreQos
> <thestarlinkmystery.png>_______________________________________________
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