Re: [quicwg/base-drafts] Rewrite of RTT estimation section (#2592)

ianswett <notifications@github.com> Thu, 11 April 2019 19:26 UTC

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Subject: Re: [quicwg/base-drafts] Rewrite of RTT estimation section (#2592)
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ianswett commented on this pull request.



> -ack delay.  Ignoring ack delay for min RTT prevents intentional or unintentional
-underestimation of min RTT, which in turn prevents underestimating smoothed RTT.
-
-A sender calculates both smoothed RTT (SRTT) and RTT variance (RTTVAR) similar
-to those specified in {{?RFC6298}}.  Note that computing smoothed_rtt does not
-use ack_delay for the first RTT sample, because doing so would result in a
-smoothed_rtt that is smaller than the min_rtt.
-
-On every newly acknowledged ack-eliciting largest acked:
+## Measuring and Reporting Host Delay {#host-delay}
+
+An endpoint measures the delay incurred between when a packet is received and
+when the corresponding acknowledgment is sent.  The endpoint encodes this host
+delay for the largest acknowledged packet in the Ack Delay field of an ACK frame
+(see Section 19.3 of {{QUIC-TRANSPORT}}).  This allows the receiver of the ACK
+to adjust for any host delays - importantly, for delayed acknowledgements - when

```suggestion
to adjust for any host delays, which is particularly important for delayed acknowledgements, when
```

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