Re: [tsvwg] Tsvart last call review of draft-ietf-tsvwg-le-phb-08

[Christian Huitema <[e-mail]>]

On 2/9/2019 5:29 PM, Brian E Carpenter wrote:

>> There is some experience of that with other scavenger modes, e.g. using LEDBAT. Slowing down to a trickle is fine, but slowing down to zero is not. In practice, many applications that are willing to use a scavenger mode will trigger an error if they see no progress for a sustained amount of time, and then they will restart the connection and remove the LEDBAT or LE option -- which of course defeats the purpose.
> Well, that's not a true scavenger application. Restarting the transport connection
> might be a reasonable option, but giving up on LE is effectively saying "lower
> effort is not really what I wanted."
>
> Anyway, I think that reinforces my point: it's an interesting discussion, but
> out of scope for this draft.


I kind of made the same point at the time, but the reasoning was that
complete lack of progress is also an indication of complete failure, so
you end up triggering the management path for failure. The typical
candidate scavenger app at Microsoft would be software update download
or telemetry upload. None of them would have accepted a scavenger mode
that completely starved them; we had to program around that.

And by the way, that's generally OK because when the apps operate at the
bottom speed they don't go in the way of VOIP, video games, etc.

But I am not going to repeat myself on the thread...

-- Christian Huitema