Re: [Bloat] Bufferbloat research: Help required

[Dave Hart <davehart@gmail.com>]

On Sun, Nov 25, 2012 at 3:21 PM, Dauran raza <dauran.raza@gmail.com> wrote:
> My name is Dauran Raza and i am currently doing Masters in Computer Science
> from University Paderborn. Currently i am researching on the Problem of
> Bufferbloat for a course under Prof Holger Karl. I have been regularly
> reading you articles on your websites about this problem and it has been
> really helpfull. I have a problem which is not answered so far through any
> research paper. I wanted to know is there any difference in Wired and
> Wireless networks caused by this problem and can you guide me with any good
> paper or article to read on.

I wish you well in your graduate studies, and I commend Prof. Holger
Karl for his interest in the topic.  I am, however, cautious that I
don't want to do your research for you.

Briefly, as you would hopefully anticipate, wireless presents more
challenges to addressing bufferbloat than wired.  For example, the
jitter (delay variability) is much worse than wired, and 802.11n
requires aggregation of multiple packets into one transmission to
achieve its higher throughputs vs. 802.11g, which further increases
jitter and complicates AQM.

Even ignoring wireless, gigabit wired is more challenging than 100
Mbit, again because techniques used to maximize peak throughput (such
as deeper transmit buffers and receive interrupt coalescing) tend to
make bufferbloat more of a challenge.

There's a theme here -- those developing network advancements have
tended to focus on maximizing achievable throughput without enough
consideration of the negative effects on bufferbloat, often (at least
historically) with no understanding of bufferbloat at all.

I pray I have not said too much already, and if I have, please convey
my apologies to Prof. Karl.

I suggest digging into the mailing list archives:

https://lists.bufferbloat.net/listinfo

I'd start with the bloat and bloat-devel lists, then the Codel-related
lists, and possibly other -devel and -commit lists.  Also, if you make
yourself useful in one or more bufferbloat.net projects, you will gain
firsthand knowledge of the issues as well as personal relationships
with people well-versed in the issues.

Thanks for your interest,
Dave Hart