Re: [quicwg/base-drafts] Rework section on persistent congestion (#3961)

[Mike Bishop <[e-mail]>]

@MikeBishop approved this pull request.



> +This duration allows a sender to send as many packets, including some in
+response to PTO expiration, as TCP does with Tail Loss Probe ({{RACK}}), before
+establishing persistent congestion, as TCP does with a Retransmission Timeout
+({{?RFC5681}}).

This many parenthetical phrases in commas is tough to parse.  Can we divide it up a little more?  Into multiple sentences, by using something other than commas, or by condensing?

```suggestion
This duration allows a sender to send as many packets before
establishing persistent congestion, including some in
response to PTO expiration, as TCP does with a Retransmission Timeout
({{?RFC5681}}) and a Tail Loss Probe ({{RACK}}).
```

> +This design does not use consecutive PTO events to establish persistent
+congestion, since application patterns impact PTO expirations. For example, a
+sender that sends small amounts of data with silence periods between them
+restarts the PTO timer every time it sends, potentially preventing the PTO timer
+from expiring for a long period of time, even when no acknowledgments are being
+received. The use of a duration enables a sender to establish persistent
+congestion without depending on the occurrence of PTOs.
+
+### Establishing Persistent Congestion
+
+A sender establishes persistent congestion on receiving an acknowledgement if at
+least two ack-eliciting packets are declared lost, and:
+
+* a prior RTT sample existed when both packets were sent;
+
+* the duration between the send times of these two packets exceeds the

Actually, I might move that third bullet to be first.  Conceptually, it frames the idea that they're the first and last packets of a 2+ packet sequence.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/3961#pullrequestreview-465397169