Re: [quicwg/base-drafts] Update ACK generation policy (#3501)

ianswett <> Sun, 22 March 2020 16:17 UTC

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Date: Sun, 22 Mar 2020 09:17:49 -0700
From: ianswett <>
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Subject: Re: [quicwg/base-drafts] Update ACK generation policy (#3501)
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ianswett commented on this pull request.

I don't want to land this for reasons posted in the issue.

> @@ -3170,11 +3170,21 @@ delayed retransmissions from the peer. For Initial and Handshake packets,
 a max_ack_delay of 0 is used. The sender uses the receiver's `max_ack_delay`
 value in determining timeouts for timer-based retransmission, as detailed in
 Section 5.2.1 of {{QUIC-RECOVERY}}.
+The max_ack_delay needs to be set so that at least several samples can

When max_ack_delay is first sent, the path RTT is not known.

-In order to assist loss detection at the sender, an endpoint SHOULD send an ACK
+An ACK frame SHOULD be generated for at least every tenth ack-eliciting

There's no mention here of ACKing more frequently for N initial packets to avoid reducing the increase in slow-start.

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