On Thu, 14 Mar 2013, Michael Welzl wrote:
As I just said to Mikael, I don't think I worded that one well. I'm
envisaging two thresholds, testing two stress levels. It a lower one, one
marks ECN-capable traffic and drops non-ECN-capable traffic; at the higher
one, one drops from all traffic. What "threshold" means in a given
algorithm is algorithm-dependent, however.
Great, I turn on ECN, and that gives me more delay, just what I want!
And, even better: the more people use ECN, the more delay everybody gets.
Could you please elaborate on how you came to this conclusion?
Seriously, I see the incentive idea behind this two-level marking idea,
but one has to carefully consider the increased delay vs. gained
throughput trade-off in such a scheme.
Why would it be better to drop the packet than to ECN-mark it?
Concrete example:
Buffer depth > 30 ms = mark ECN traffic, drop non-ECN traffic
Buffer depth > 50 ms = drop all draffic
The congestion signal to TCP at buffer depth 30 ms is the same for both
ECN and non-ECN traffic, so I don't see how this would increase the delay?
--
Mikael Abrahamsson email: [email protected]
