[tor-relays] Tor bandwidth scanner "longclaw" slow to the US West Coast

[juga]

Hi,

thanks for reporting this issue. Replying inline:

Neel Chauhan:
> Hi,
> 
> I believe the Tor bandwidth scanner nicknamed "longclaw" is measuring
> relays in the US West Coast worse than other bandwidth scanners in North
> America. This happens on multiple ISPs, both ones I have and ones I don't.

Tor bandwidth scanners and directory authorities not necessarily run in
the same machine/IP and it's the case of longclaw's bandwidth scanner,
which is located in the US East Coast.

> 
> This includes two Tor exit instances on a dedicated server hosted in Los
> Angeles on Psychz Networks (AS40676):
> 
> https://metrics.torproject.org/rs.html#details/156AAC3FAD1ACC8906316519DCB444B8C77E4EBF
> 
> https://metrics.torproject.org/rs.html#details/A69CEB30328B1E85C6B167FECAF2F509CBD9517F
> 
> 
> And two Tor non-exit instances on a home server in Seattle on Wave
> Broadband (AS11404), using a symmetrical Gigabit link:
> 
> https://metrics.torproject.org/rs.html#details/B0F9BA27944FA59E3B1A182208FF7C0CFF5497B2
> 
> https://metrics.torproject.org/rs.html#details/DB710B14D7329B7289CFCC547F48EF53F812C40D
> 
> 
> The consensus weight values from longclaw are much lower than other
> North American bandwidth scanners, according to
> https://consensus-health.torproject.org/.
> 
> This also affects other relays/ISPs on the West Coast US/Canada, such as
> Emerald Onion, AT&T U-verse, Sonic.net, and QuadraNet. The same
> ISPs/hosts in the East Coast aren't affected.
> 
> This discrepancy in the measurement disproportionately favors European
> and East Coast US/Canada relays at the expense of West Coast relays,
> centralizing the Tor network even further than it already was. This
> wasn't an issue in the past, even as early as a few months ago. It only
> started appearing around June.

If the reason for lower bandwidth measurements is the location -it could
be other reasons- then it's weird that it would affect the US West Coast
and not Europe, given it's located in the US East Coast.

To understand why this is happening, it's very helpful that you give us
this information.
I personally suspect it might not be related to the scanner location.
We'll investigate this as part of the issue you opened at
https://gitlab.torproject.org/tpo/network-health/sbws/-/issues/40014.

It might take some weeks, since a lot of the work done on this topic is
volunteer work. Apologies in advance about it.

> 
> Is anyone else hosting West Coast relays having this issue? 

Good question.

Is
> "longclaw" actually measuring bandwidth from Europe? If so, WHY?

No, it's not measuring bandwidth from Europe.

> 
> I got in contact with "longclaw"'s admin and he wasn't too helpful.

It looks to me that the longclaw's admin has been helpful if they have
suggested you to write to this mailing list, so that more people can
check this issue and/or they have suggested you to report an issue in
gitlab so that the bandwidth scanner developers won't forget about it :)

Also, not all directory authorities run bandwidth scanners and not all
of them know about the complexity on how bandwidth is determined.

Hope it helps.

Best,
juga

-- 
they/them

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