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Re: [quicwg/base-drafts] Update initial congestion window on MTU decrease (#3998)

Martin Thomson <notifications@github.com> Mon, 17 August 2020 01:41 UTC

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Date: Sun, 16 Aug 2020 18:41:55 -0700
From: Martin Thomson <notifications@github.com>
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Subject: Re: [quicwg/base-drafts] Update initial congestion window on MTU decrease (#3998)
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@martinthomson commented on this pull request.



> +If the maximum datagram size is decreased in order to complete the handshake,
+the initial congestion window SHOULD be recalculated with the new smaller size.
+This avoids overly large initial congestion windows.  The initial window is
+not recalculated at any other time.

So I'm concerned about other places we use the initial window.  One is where you go idle and decide to reset the congestion window.  Another is where you move to a new path.  The former is interesting in this case because the MTU might carry across.  The latter, less so.

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