Re: [quicwg/base-drafts] Add more context and text around ACK frequency (#3706)

[ianswett <[e-mail]>]

@ianswett commented on this pull request.



> -received packet. Limiting ACK frames avoids an infinite feedback loop of
-acknowledgements, which could prevent the connection from ever becoming idle.
-However, the endpoint acknowledges non-ACK-eliciting packets when it sends an
-ACK frame.
+### Acknowledgement Frequency
+
+A receiver determines how frequently to send acknowledgements in response to
+ack-eliciting packets. This determination involves a tradeoff.
+
+Endpoints rely on timely acknowledgment to detect loss; see Section 5 of
+{{QUIC-RECOVERY}}. Window-based congestion controllers, such as the one in
+Section 6 of {{QUIC-RECOVERY}}, rely on acknowledgments to manage their sending
+rate. In both cases, delaying acknowledgment can adversely affect performance.
+
+On the other hand, reducing the frequency of packets that carrying only
+acknowledgements reduces packet processing cost at both endpoints. It can also

Now that I read this again, I'm actually not sure what you mean.  Do you mean packet processing cost as in the cost of receiving a large number of data packets, so fewer ACK-only packets reduces that cost?

I was thinking you were saying it reduces the number of ACKs that have to be received and processed.

Either way, I have a small suggestion.
```suggestion
acknowledgements reduces packet transmission and processing cost at both endpoints. It can also
```

> -received packet. Limiting ACK frames avoids an infinite feedback loop of
-acknowledgements, which could prevent the connection from ever becoming idle.
-However, the endpoint acknowledges non-ACK-eliciting packets when it sends an
-ACK frame.
+### Acknowledgement Frequency
+
+A receiver determines how frequently to send acknowledgements in response to
+ack-eliciting packets. This determination involves a tradeoff.
+
+Endpoints rely on timely acknowledgment to detect loss; see Section 5 of
+{{QUIC-RECOVERY}}. Window-based congestion controllers, such as the one in
+Section 6 of {{QUIC-RECOVERY}}, rely on acknowledgments to manage their
+congestion window. In both cases, delaying acknowledgments can adversely affect
+performance.
+
+On the other hand, reducing the frequency of packets that carrying only

```suggestion
On the other hand, reducing the frequency of packets that carry only
```

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