[tor-relays] Question regarding bandwidth ratio on bridges.torproject.org and a few further, small, (probably related) questions

[meskio]

Quoting telekobold (2023-07-05 17:56:35)
> I'm operating two Tor bridges. When calling bridges.torproject.org, for one of 
> the bridges (set up in March, 2023), there are three outputs:
> - obfs4: functional
> - a bandwidth ratio
> - a "last tested" entry.
> But for my second bridge (set up at the beginning of June 2023), 
> bridges.torproject.org does not output a bandwidth ratio.
> 
> What does this missing bandwidth ratio output mean, since everything else 
> seems to be normal?

The bandwidth ratio is measured by onbasca[0]. Is a ratio of how fast is your 
bridge compared to the rest of bridges, 1 means average (for some definition of 
average), lower than 1 means is slower than others, higher than 1 means is 
faster than others. rdsys uses that ratio to decide if some of the bridges 
should not be distributed.

This is a recent setup (some months) and we are still testing it. It looks like 
some bridges are failing to be tested by onbasca, we need to investigate why[1]. 

rdsys will do distribute bridges without a bandwidth ratio, so your bridge 
without it should be distributed normally as long as is functional.


[0] https://gitlab.torproject.org/tpo/network-health/onbasca/
[1] https://gitlab.torproject.org/tpo/network-health/onbasca/-/issues/157


> I am honestly not quite sure to what extent the fingerprint of the bridge is 
> information worth protecting, or whether only the port and IP address need to 
> be protected.

You should keep the fingerprint private, as it can be used to retrieve the port 
and IP of the bridge. But is ok to publish the hashed fingerprint.

> By the way, I also don't understand why my two bridges don't have a higher 
> advertised bandwidth - currently, it's 4.87MiB/s for one and 1.43MiB/s for the 
> other relay. I never got the fast flag for either bridge yet, in contrast to 
> my two "normal" relays. On both servers, at least 1.6GiB/s is available, and a 
> monthly data throughput of several terabytes.

Bridges can not get a 'fast' flag, those flags are only for relays. The flag 
comes from the bandwidth authority, but we don't run one for bridges.

> And, as a last issue, I didn't specify a distribution mechanism for my bridge, 
> in the hope that the most suitable mechanism will be selected automatically. 
> Initially, for one of my bridges (the one for which bridges.torproject.org 
> outputs a bandwidth ratio) the bridge was assigned distribution mechanism 
> "Moat". But suddenly, "None" is displayed under distribution mechanisms at 
> metrics.torproject.org, which means that apparently the bridge is no longer 
> distributed. What could be the reason that the distribution mechanism suddenly 
> changed?

I don't know, as long as your bridge is functional it should have a distribution 
mechanism assigned. Do you mind sharing with me the hashed fingerprint of the 
bridge to look at it? (it can be in private)

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