> On 9 Jun, 2015, at 21:29, Steven Blake <[email protected]> wrote: > > That's great, but I'm talking about how to do AQM on Nx100 Gbps packet > processing ASICs, not Linux boxes. And I agree that FQ is desirable, > but not always cost effective or feasible to retrofit.
Ah, you are talking about core networks. That’s a little out of my area of expertise, but… As I understand it, core networks are generally supposed to be over-provisioned. However, even a nominally over-provisioned link can be saturated in the short-term and/or at peak load. A straightforward AQM system is useful for coping with that. There is a well-known theory which states that, for a dumb FIFO, queue length can be reduced from the “BDP rule of thumb” to BDP * sqrt(flows) in the case where a large number of flows is normally expected. This is the case for core networks, but not the edge (where the link is routinely saturated by a single flow). I think it’s reasonable to suppose that the same theory might apply to Codel parameters. If so, taking a nice round number of 10000 flows (since you can’t predict it very precisely, an order of magnitude or two is sufficient), the new parameters would be interval=1ms and target=50us. If you re-run your analysis using those parameters, do you get more reasonable behaviour? Intuitively, I think you should get similar per-packet behaviour at 100G using those parameters, as at 1G using the defaults. - Jonathan Morton _______________________________________________ aqm mailing list [email protected] https://www.ietf.org/mailman/listinfo/aqm
