[iccrg-slowstart 00007] Re: [Iccrg] SSDT contributions

[Dirceu Cavendish]

Michael,

Good charts. Question: how did you pick the specific 82Mbps and 5.1Mbps request values? Why didnt you request 9Mbps on a 10Mbps link?

Dirceu



----- Original Message ----
From: Michael Scharf <michael.scharf at ikr.uni-stuttgart.de>
To: iccrg-slowstart at infonet.cse.kyutech.ac.jp
Cc: iccrg IRTF list <iccrg at cs.ucl.ac.uk>
Sent: Tuesday, April 15, 2008 12:33:04 PM
Subject: [iccrg-slowstart 00007] Re: [Iccrg] SSDT contributions

Dirceu,

in simple usage scenarios (e. g., HTTP/1.0-like communication) the
impact of Slow-Start is rather obvious, as well as the potential
speedup that faster algorithms could achieve.

The attached slides show some Linux measurement results that compare
the Slow-Start with Quick-Start (best case). There can be a
performance improvement of one second or more, which is typically
"user perceivable". The difference would be even larger if the TCP
stacks used delayed ACKs (Linux disables them sometimes). Of course,
the larger the RTT, the more significant is the effect.

I also have data for more realistic HTTP request patterns, but in this
case the Slow-Start impact is more difficult to quantify and depends a
lot on the application communication pattern.

Michael

On Fri, 11 Apr 2008 at 10:45:20, Dirceu Cavendish wrote:
> Michael,
> 
> I think the "user perceivable" impact of faster SS algorithms should be documented within ICCRG. Do you have data backing that up (for any application of your choice)?
> 
> I am attaching few slides on experimental results in reducing segment losses during SS, for discussion. As presented in Manchester, we reduce losses by both reducing the speed of cwnd increase (in a fractional rather than by 1 way), as well as NOT transmitting the entire cwnd on a back-to-back fashion - introducing "micro-pauses" during transmissions...
> 
> Dirceu


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