recovery pseudocode enters "recovery" after "slow start"

[kazu-yamamoto]

The spec says that "congestion avoidance" after "slow start". However, it seems to me that pseudocode enters "recovery" after "slow start".

When packets are lost, OnCongestionEvent is called:

OnCongestionEvent(sent_time):
  // Start a new congestion event if packet was sent after the
  // start of the previous congestion recovery period.
  if (!InCongestionRecovery(sent_time)):
    congestion_recovery_start_time = now()
    congestion_window *= kLossReductionFactor
    congestion_window = max(congestion_window, kMinimumWindow)
    ssthresh = congestion_window
    // A packet can be sent to speed up loss recovery.
    MaybeSendOnePacket()

This function sets congestion_recovery_start_time if the state is not "recovery", which means either "slow start" or "congestion avoidance". So, "recovery" starts after "slow start".

[janaiyengar]

@kazu-yamamoto : you are right; perhaps this could be made part of #3982?

[kazu-yamamoto]

@janaiyengar Better definition of each state is welcome. But I'm talking about the pseudocode. My implementation based on the pseudocode enters "recovery" after "slow start". That's why I noticed this issue. We should fix the pseudocode somehow. (To fix this bug, I introduced a variable to hold the state explicitly in Haskell quic.)

[martinthomson]

Entering recovery after slow start is correct. The language in the draft was confusing. Hopefully #4055 helps there.

[kazu-yamamoto]

The language in the draft was confusing.

Indeed...

[kazu-yamamoto]

After merging #4055, the pseudocode matches the language. Let's close this.

[martinthomson]

Let's leave this open until #4055 merges then.