Re: [quicwg/base-drafts] Attempt to define slow start/congestion avoidance (#4005)

[mirjak <[e-mail]>]

@mirjak commented on this pull request.



> -Additive Increase Multiplicative Decrease (AIMD) approach that increases
-the congestion window by one maximum packet size per congestion window
-acknowledged.  When a loss or ECN-CE marking is detected, NewReno halves
-the congestion window, sets the slow start threshold to the new
-congestion window, and then enters the recovery period.
+The congestion controller is in congestion avoidance any time the congestion
+window is at or above the slow start threshold.
+
+Congestion avoidance uses an Additive Increase Multiplicative Decrease (AIMD)
+approach that increases the congestion window by one maximum packet size per
+congestion window acknowledged.
+
+When first entering congestion avoidance, when a packet is declared lost, or
+when the ECN-CE count is detected, the congestion controller halves the
+congestion window, reduces the slow start threshold to the resulting size, and
+enters the recovery period.

I think the MUST requirement is that the cwnd is set to ssthresh when LEAVING recovery. In order to decrement the cwnd gradually we could say that only one new packet for two ACKed ones should be send which then would be mostly inline with TCP or we can leave the detailed scheme to the implementation and just put some warnings to not overload the link in recovery. Alternatively you could also e.g. halve the cwnd and then pace out packets over one RTT (which is assume is what implementation do right now?)

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/4005#discussion_r472901102