[Codel] [RFC PATCH] codel: ecn mark at target

Eric Dumazet eric.dumazet at gmail.com
Sat Aug 4 02:45:38 EDT 2012

On Fri, 2012-08-03 at 19:44 -0700, Dave Täht wrote:
> From: Dave Taht <dave.taht at bufferbloat.net>
> The consensus at ietf was that ecn marking should start at
> target, and then the results fed into the codel drop scheduler.
> While I agree with the latter, I feel that waiting an interval
> before starting to mark will be more in-tune with the concept
> of a sojourn time, and lead to better utilization.
> As I am outnumbered and outgunned, do it at target.

Well, thats a huge way to favor non ECN flows against ECN flows.

Marking _all_ ECN enabled packets just because last packet sent had a
sojourn time above target is going to throttle ECN flows and let non ECN
flows going full speed and take whole bandwidth.

Doing so is a nice way to keep users switching to ECN one day.

IETF could just say : ECN is doomed, forget about it, dont even try. 

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