Re: [quicwg/base-drafts] Ignoring ACK delay can result in wrong RTT calculations (#3350)

[kixelated <[e-mail]>]

Using the above example, where we expect `smoothed_rtt=100` and `rttvar=0.6`

Here is the problematic code. It produces `smoothed_rtt=116.6` and `rttvar=10.4`
```
    adjusted_rtt = latest_rtt
     if (latest_rtt > min_rtt + ack_delay):
       adjusted_rtt = latest_rtt - ack_delay
```

Like @ianswett said, an improvement would be to use the `ack_delay` while `adjusted_rtt >= min_rtt`:

``
    adjusted_rtt = min(latest_rtt - ack_delay, min_rtt)
``

It produces `smoothed_rtt=100.3` and `rttvar=0.4`. However, this will still over-estimate the smooth and under-estimate the variance.

-- 
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/issues/3350#issuecomment-574837523