[p2p-hackers] Hard question....

Daniel Stutzbach agthorr at cs.uoregon.edu
Mon Apr 3 18:13:36 UTC 2006

On Sun, Apr 02, 2006 at 10:58:05PM -0700, David Barrett wrote:
> > From: Daniel Stutzbach
> > That is not actually the right question, because the answer is
> > typically "None or very, very little".  TCP's goal is to achieve
> > saturation and not leave unused capacity.  If you try to measure the
> > "available bandwidth" that TCP leaves behind, you're not going to have
> > much to work with.
> Um... most connections aren't saturated 24x7.  

Well, sure, but anytime there's another bulk transfer going on in the
background, "available bandwidth" measurements are not very useful.
That's all I'm saying ;)

> Like, I have a 6Mbps connection and sometimes I'm just using AIM.
> In this situation, I'd like to measure that 5.9Mbps is free.  Any
> clever ideas on how to accomplish this?

There are bunch of heuristic techniques to estimate the available
bandwidth, but I'm not an expert on them.  Search for "available
bandwidth estimation" and "packet pair".

Daniel Stutzbach                           Computer Science Ph.D Student
http://www.barsoom.org/~agthorr                     University of Oregon

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