[mat-wg] [routing-wg] RIPE Labs post: Does The Internet Route Around Damage?

> We analysed last week's AMS-IX outage from the perspective of RIPE
> Atlas, to shed some light on the question if the Internet routes
> around damage.

> Our analysis is here:
> https://labs.ripe.net/author/emileaben/does-the-internet-route-around-damage-edition-2023/

Great analysis, thanks! A few questions/observations/suggestions for
further analysis by aspiring routing researchers...

On IXP-less backup paths:

  "The main alternative in our data are paths without IXP. This could be
  a direct lateral peering that is not IXP-mediated, or using transit
  instead of the IXP."

Would it be possible to distinguish between those cases? Maybe by
looking at any additional ASes that show up in the new paths, and trying
to detect provider/customer relationships using some known approach.
Intuitively the second case seems more "normal", because if you had a
direct peering (PNI), then why would you have preferred AMS-IX in the
first place? But of course it's possible that those non-IXP-mediated
peerings are over slower links or otherwise inferior.

On the belated NL-IX rerouting:

This indeed looks like an intentional change of routing preferences;
looking at the steep/vertical increases, probably done by a single or a
few large providers.  Now I'm of course very curious who did this (and
was able to shift about 15% of all Atlas traceroutes around :-).

Cheers,
-- 
Simon.