[Bloat] Network computing article on bloat

Dave Taht dave.taht at gmail.com
Tue Apr 26 17:16:57 EDT 2011


On Tue, Apr 26, 2011 at 2:30 PM, Constantine Dovrolis
<dovrolis at cc.gatech.edu> wrote:
> Thanks Wes - I was hoping that someone will make this point.
>
> btw, another common reason for lossless operation is the
> size of the flows. basically flows often finish before their
> window increases so much that they overflow their bottleneck's
> buffer.

We do tend to overuse TCP for short flows, like those of the core http
protocol without 1.1 pipelining. However more uptake of 1.1's
pipelining would lead to more correct and timely behavior in the
presence of congestion, and longer flows in the general case.

That said in an age of netflix and facetime, we have problems with big
flows again.

>
> Plz spend some time to read the following paper:
> http://www.cc.gatech.edu/fac/Constantinos.Dovrolis/Papers/buffers-ton.pdf

The paper above appears to be testing against networks in the USA, and
at speeds higher than 1Mbit.

Did you try working internationally, at speeds closer to 128Kbit?

> It is very relevant to the bufferbloat initiative and it shows clearly,
> I think, that statements like "Big Buffers Bad. Small Buffers Good."
> are crude oversimplifications that will cause even more confusion.

I think they are crude simplifications, but they lead to slightly more
correct conclusions in the general case than the alternatives. I would
love to have a short elevator pitch that nailed the problem
adequately.



>
> regards
>
> Constantine
>
> On 4/26/2011 4:21 PM, Wesley Eddy wrote:
>>
>>
>> Operating with infinite storage and operating without packet loss are
>> two different things.
>>
>> Ideally, you may have a path with ample bandwidth such that packet
>> losses don't occur and all connections are either application limited or
>> receive window limitedand congestion control never kicks in. In this
>> case, there's no loss and the Internet clearly works.
>>
>
> --------------------------------------------------------------
> Constantine Dovrolis, Associate Professor
> College of Computing, Georgia Institute of Technology
> 3346 KACB, 404-385-4205, dovrolis at cc.gatech.edu
> http://www.cc.gatech.edu/~dovrolis/
>
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>



-- 
Dave Täht
SKYPE: davetaht
US Tel: 1-239-829-5608
http://the-edge.blogspot.com



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