Re: [quicwg/base-drafts] Reword Immediate ACK Recommendation (#2424)

ianswett <> Mon, 11 February 2019 20:28 UTC

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Subject: Re: [quicwg/base-drafts] Reword Immediate ACK Recommendation (#2424)
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ianswett commented on this pull request.

I'm confused about what problem you're trying to fix with the immediate ACK text.  Can you clarify?

> @@ -135,6 +135,12 @@ Crypto Packets:
 : Packets containing CRYPTO data sent in Initial or Handshake
+Out-of-order Packets:
+: Packets that do not increase the largest received packet number for its
+packet number space by exactly one. Packets usually arrive out of order

Duplication doesn't count as out-of-order because the packet is ignored.  Misbehaving senders are certainly possible, but I'm not sure how important they are to this text?

> @@ -244,11 +250,11 @@ ack-eliciting packet. QUIC recovery algorithms do not assume the peer sends
 an ACK immediately when receiving a second ack-eliciting packet.
 In order to accelerate loss recovery and reduce timeouts, the receiver SHOULD
-send an immediate ACK when it receives a new packet which is not one greater
-than the largest received packet number. A receiver MAY send immediate ACKs
-for the next few ack-eliciting packets that are received, but SHOULD NOT
-send an immediate ACK for more than 1/8 RTT after receiving an out-of-order
+send immediate ACKs for an interval after it receives an out-of-order packet.
+This interval SHOULD be between zero (immediately acking only out-of-order

I'm finding this increasingly hard to read.  Can we pop the stack and you can explain what's unclear about the existing text?

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