[tor-relays] Measuring the Accuracy of Tor Relays' Advertised Bandwidths

[Roger Dingledine]

On Tue, Aug 06, 2019 at 05:31:39PM -0400, Rob Jansen wrote:
> Today, I started running the speedtest on all relays in the network. So far, I have finished about 100 relays (and counting). I expect that the advertised bandwidths reported by metrics will increase over the next few days. For this to happen, the bandwidth histories observed by a relay during my speedtest are first committed to the bandwidth history table (within 24 hours), and then reported in the server descriptors (within 18-36 hours, depending on when the bandwidth history commit happens).

Great.

There will be another confusing (confounding) factor, which is that the
weights in the consensus are chosen by the bandwidth authorities, so
even if the relay's self-reported bandwidth goes up (because it now sees
that it can handle more traffic), that doesn't mean that the consensus
weight will necessarily go up. In theory it ought to, but with a day or
so delay, as the bwauths catch on to the larger value in the descriptor;
but in practice, I am not willing to make bets on whether it will behave
as intended. :) So, call it another thing to keep an eye out for during
the experiment.

Woo,
--Roger