Re: [quicwg/base-drafts] Persistent Congestion Time Threshold (#2365)

ianswett <notifications@github.com> Mon, 11 February 2019 20:12 UTC

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Subject: Re: [quicwg/base-drafts] Persistent Congestion Time Threshold (#2365)
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ianswett commented on this pull request.



> +  rttvar = 0
+  max_ack_delay = 0
+  kPersistentCongestionThreshold = 2
+
+If an eck-eliciting packet is sent at time = 0, the following scenario would
+illustrate persistent congestion:
+
+  t=0 | Send Pkt #1 (App Data)
+  t=1 | Send Pkt #2 (PTO 1)
+  t=3 | Send Pkt #3 (PTO 2)
+  t=7 | Send Pkt #4 (PTO 3)
+  t=8 | Recv ACK of Pkt #4
+
+The first three packets are determined to be lost when the ACK of packet 4 is
+received at t=8.  The congestion period is calculated as the time between the
+oldest and newest lost packets: (3 - 0) = 3.  The duration for persistent

The text is normative and the pseudocode is an appendix.  I'm ok with the pseudocode not being perfect, especially for cases that are fairly unlikely in practice.

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