* Re: [Codel] fq_Codel vs Sfq_Codel
2015-02-28 17:58 ` Dave Taht
@ 2015-02-28 21:09 ` Dave Taht
2015-02-28 23:36 ` Tom Henderson
1 sibling, 0 replies; 4+ messages in thread
From: Dave Taht @ 2015-02-28 21:09 UTC (permalink / raw)
To: divya singla, Tom Henderson; +Cc: codel
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@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@gmail.com> wrote:
>> can anybody tell me is there any difference between fq_Codel and Sfq_Codel?
>>
>>
>>
>> _______________________________________________
>> Codel mailing list
>> Codel@lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/codel
>>
>
>
>
> --
> 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Codel] fq_Codel vs Sfq_Codel
2015-02-28 17:58 ` Dave Taht
2015-02-28 21:09 ` Dave Taht
@ 2015-02-28 23:36 ` Tom Henderson
1 sibling, 0 replies; 4+ messages in thread
From: Tom Henderson @ 2015-02-28 23:36 UTC (permalink / raw)
To: Dave Taht, divya singla; +Cc: codel
On 02/28/2015 09:58 AM, Dave Taht 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?
Dave and all,
The status of ns-2 and ns-3 support is as follows.
In ns-2, some new models (CoDel, SFQCoDel, CoDel-DT, and PIE)
contributed by Kathleen Nichols, CableLabs, and Cisco will be part of
the ns-2.36 release, which is in preparation. An initial release
candidate was posted here:
http://nsnam.isi.edu/nsnam/index.php/Roadmap#Release_candidates_for_testing
and the code in the CVS tree is consistent with this. (Preview)
documentation on the new models is available here:
http://www.isi.edu/nsnam/dist/release/rc1/doc/node69.html
and here:
http://www.isi.edu/nsnam/dist/release/rc1/doc/node89.html
When will 2.36 be released? I am working through a long list of issues
getting the debug build to work on clang-based systems, and when those
are resolved (in the next few weeks?) I'll release 2.36. The release
candidate above is pretty close to what will be the final bits.
In ns-3, basic CoDel was added in n-3.21. Dave and Andrew McGregor
contributed some models for FQ- and SFQ-CoDel a while back; links to
this code can be found on our wiki Current Development page. Inclusion
of these is blocked by some stack refactoring that Dave pointed to in a
subsequent post, to insert a priority queue sublayer for these queues.
I'm working towards the goal of making these available by ns-3.23 (May),
but I aimed for ns-3.22 and missed, so I can't promise that these will
be done by May; we'll see.
If anyone wants to help test these new simulation models and get them
into shape for release, please contact me.
- Tom
^ permalink raw reply [flat|nested] 4+ messages in thread