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[quicwg/base-drafts] recovery pseudocode enters "recovery" after "slow start" (#4045)

Kazu Yamamoto <notifications@github.com> Tue, 25 August 2020 00:56 UTC

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Date: Mon, 24 Aug 2020 17:56:16 -0700
From: Kazu Yamamoto <notifications@github.com>
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Subject: [quicwg/base-drafts] recovery pseudocode enters "recovery" after "slow start" (#4045)
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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".

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