Re: [quicwg/base-drafts] Change PTO to be per packet number space (#3066)

ianswett <> Mon, 28 October 2019 21:58 UTC

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Date: Mon, 28 Oct 2019 14:58:21 -0700
From: ianswett <>
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Subject: Re: [quicwg/base-drafts] Change PTO to be per packet number space (#3066)
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ianswett commented on this pull request.

> @@ -477,6 +477,9 @@ limited by the endpoint's idle timeout.
 A sender computes its PTO timer every time an ack-eliciting packet is sent.
 When ack-eliciting packets are in-flight in multiple packet number spaces,
 the timer MUST be set for the packet number space with the earliest timeout.
+Even when there are ack-eliciting packets in-flight in multiple packet number
+spaces, the exponential increase in probe timeout occurs across all spaces to

I removed the 1 packet limit when not coalescing when pointing out this existing exponential backoff behavior, so it should be:
 time 0: send first flight
 time P: send Initial and Handshake
 time 2P: Send 1RTT and Initial
 time 4P: send Handshake and 1RTT

Hopefully before 2P the server receives an ACK of something anyway, since that's seconds into the connection.

But we may want to tweak this as a result of the discard keys conclusion.

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