commit 764abbfdea60b6a709801b244a2e3a798858a491 Author: Nick Mathewson <nickm@torproject.org> Date: Mon Aug 16 12:25:27 2021 -0400 Specify the exact "fraction of paths" calculation that Tor uses. --- path-spec.txt | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/path-spec.txt b/path-spec.txt index 092e8d4..f02bee6 100644 --- a/path-spec.txt +++ b/path-spec.txt @@ -144,6 +144,23 @@ of their choices. NUM_GUARDS_TO_USE guards among our primary guards. (see guard-spec.txt) + We define the "fraction of bandwidth-weighted paths" as the product of + these three fractions. + + * The fraction of descriptors that we have for nodes with the Guard + flag, weighted by their bandwidth for the guard position. + * The fraction of descriptors that we have for all nodes, + weighted by their bandwidth for the middle position position. + * The fraction of descriptors that we have for nodes with the Exit + flag, weighted by their bandwidth for the exit position. + + If the consensus has zero weighted bandwidth for a given kind of + relay (Guard, Middle, or Exit), Tor instead uses the fraction of relays + for which it has the descriptor (not weighted by bandwidth at all). + + If the consensus lists zero exit-flagged relays, Tor instead uses the + fraction of middle relays. + 2.1.1. Clients build circuits preemptively