[Codel] fq_Codel vs Sfq_Codel

[Dave Taht]

ah, it looks like tom is making some progress on ns3 here:

http://code.nsnam.org/tomh/ns-3-dev-aqm

On Sat, Feb 28, 2015 at 9:58 AM, Dave Taht <dave.taht at gmail.com> wrote:
> sfq_codel in ns2 is derived more from SFQ than DRR, and there are
> several substantial differences, although sfq_codel  can be almost,
> but not quite, configured to act the same as the dual DRR version that
> is in the actual, shipping, fq_codel. The version of DRR fq_codel uses
> is more similar to "DRR+" and "DRR++", but is uniquely it's own.
>
> You have to use sfq_codel VERY carefully in the ns2 version, as the
> ability to correctly generate a five tuple hash is not there.
> Correctly generating a 5 tuple is almost, but not quite, in the ns3
> version, last I looked, and that ns3 version is MUCH closer to the
> actual fq_codel version deployed in the field, but still not quite the
> same thing.  I have kind of lost track as to the right ns2 and ns3
> versions to start from, also. Tom?
>
> in terms of setting up realistic scenarios: A common (actually, nearly
> universal) change to fq_codel in the field at low bandwidths (below
> 50mbit) is to use a reduced quantum (300 bytes). I don't remember how
> to do that right in the ns2 version. It has, after all, been 3 years
> of no interest from the academic community. Also the codel target and
> interval need to be tuned slightly, at below 2.5mbits to account for a
> single full length packet at those speeds.
>
> I am delighted by the sudden upsurge in interest in the *fq_codel
> versions but I would certainly appreciate more efforts on making the
> underlying simulations actually match the deployment, before everyone
> goes off writing papers again.
>
> See sch_fq_codel.c in the linux distributions since 3.6, see also
> codel.h there, and compare against what you have for ns2 and ns3.
>
> I completely lack time or funding to make sims match the (much better
> reality) at this point. Worst case, I would encourage you to test the
> sims verses the deployed code with the same exact tests, so you can
> see what differences exist.
>
>
> On Sat, Feb 28, 2015 at 9:34 AM, divya singla <divyasingla1989 at gmail.com> wrote:
>> can anybody tell me is there any difference between fq_Codel and Sfq_Codel?
>>
>>
>>
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>
>
> --
> Dave Täht
> Let's make wifi fast, less jittery and reliable again!
>
> https://plus.google.com/u/0/107942175615993706558/posts/TVX3o84jjmb



-- 
Dave Täht
Let's make wifi fast, less jittery and reliable again!

https://plus.google.com/u/0/107942175615993706558/posts/TVX3o84jjmb