Re: [quicwg/base-drafts] Changing the Default QUIC ACK Policy (#3529)

Gorry Fairhurst <> Sat, 28 March 2020 10:16 UTC

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Date: Sat, 28 Mar 2020 03:16:52 -0700
From: Gorry Fairhurst <>
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Subject: Re: [quicwg/base-drafts] Changing the Default QUIC ACK Policy (#3529)
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I think this isn't the correct question. This is about the default policy. 
The default policy is about what a receiver does by "default" - the current text uses a value of ACK every other packet, 1:2. TCP specified this when transmission rates were low, and TCP depended on individual ACKs to clock data (no pacing, IW=2), detect loss (no PTO), increase cwnd (per ACK packet), etc. In response, TCP causes ACK congestion and strange interactions with radio access. Performance over WiFi, DOCSIS etc suffers unless the network tries to address this. 
I don't see why QUIC, which doesn't rely on any of these, needs to set a DEFAULT of 1:2. This is literally a few lines of code difference, and we could use 1:10.
These CC's you mention may have different needs and that needs to be handled by telling the remote that your CC has these specific needs - which I think is what Jana's extension is about. 

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