Re: [aqm] AQM schemes: Queue length vs. delay based

[Anoop Ghanwani <[e-mail]>]

On Thu, Nov 14, 2013 at 5:33 PM, Preethi Natarajan <[e-mail]>wrote:
>
>
> Just pointing out the evidence here --
> http://www.ietf.org/proceedings/86/slides/slides-86-iccrg-5.pdf
>
> The slides contain preliminary results from DC scenarios, showing PIE's
> parameters and adaptability to DC scenarios. Thank god for the IETF
> archives :)
>
> Hi Preethi,

In these simulations what was the buffer size used?  From my read, it looks
like the setup had ~400 KB per port before any marking/discarding would
take place.  This is significantly more than what is available in
top-of-the-rack switches used in many data centers.

This should give you an idea of the kind of buffering that is actually
available.  As port-counts go up, the amount of buffering per port goes
down.
http://people.ucsc.edu/~warner/buffer.html

For the simulations to be relevant for such switches, they would have to be
done with significantly smaller buffer sizes.  The sizing gets even worse
when we consider there may be multiple priorities and some of those may be
lossless (requiring dedicated buffers be set aside for them).

Anoop