commit 52eebf04ce6bd828e9535e1759a18bd3c3caa3e6 Author: Mike Perry <mikeperry-git@torproject.org> Date: Tue Jul 21 12:22:17 2020 -0500 Toke Høiland-Jørgensen recommends using INTERVAL for ECN. Otherwise he suspsects that circuits will exit slow start too early. --- proposals/324-rtt-congestion-control.txt | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/proposals/324-rtt-congestion-control.txt b/proposals/324-rtt-congestion-control.txt index b96c2f7..eede20b 100644 --- a/proposals/324-rtt-congestion-control.txt +++ b/proposals/324-rtt-congestion-control.txt @@ -192,12 +192,18 @@ outbuf. The duration of total circuitmux queue time for each cell will be compared a consensus parameter 'min_queue_target', which is set to 5% of -min network RTT. (This mirrors the CoDel parameter of the same name). - -As soon as a cell of a circuit spends more than this time in queues, a -per-circuit flag 'ecn_exit_slow_start' will be set to 1. As soon as a -cell is available in the opposite direction on that circuit, the relay -will flip the cell_t.command of from CELL_COMMAND_RELAY to +min network RTT. (This mirrors the CoDel TARGET parameter). + +Additionally, an inspection INTERVAL parameter 'queue_interval' governs +how long queue lengths must exceed 'min_queue_target' before a circuit +is declared congested. This mirrors the CoDel INTERVAL parameter, and it +should default to approximately 50-100% of average network RTT. + +As soon as the cells of a circuit spend more than 'min_queue_target' +time in queues for at least 'queue_interval' amount of time, per-circuit +flag 'ecn_exit_slow_start' will be set to 1. As soon as a cell is +available in the opposite direction on that circuit, the relay will flip +the cell_t.command of from CELL_COMMAND_RELAY to CELL_COMMAND_RELAY_CONGESTION. (We must wait for a cell in the opposite direction because that is the sender that caused the congestion). @@ -849,6 +855,13 @@ important to tune first): - Range: [1, 10000] - Default: 10 + queue_interval: + - Description: How long in milliseconds must cells exceed + 'min_queue_target' queue delay before we actually send a + congestion signal? + - Range: [1, 10000] + - Default: 200 + xoff_client xoff_mobile xoff_exit @@ -1122,4 +1135,3 @@ per circuit, at most. 25. Tor Performance Metrics for Live Network Tuning https://trac.torproject.org/projects/tor/wiki/org/roadmaps/CoreTor/Performan... -