Re: Re the default linux tcp algorithm being changed from bic to cubic.

On Thu, 28 Sep 2006 11:07:18 +0100
Douglas Leith [off-list ref] wrote:

Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

Steve,

I think we're all conscious of the fact that recent history contains 
quite a number of proposals for changes to tcp's congestion control 
algorithm for high bandwidth-delay product paths that on closer 
inspection have proved problematic in one way or another.   It seems to 
be a hard problem to solve, so maybe that's fair enough and hopefully 
we'll end up with a workable solution soon.

Where I'm coming from here though is that bic was made the linux default 
a year or so ago at a time when there were essentially no tests 
available on its performance other than the infocom paper by Injong. 
Subsequent tests have since highlighted a bunch of issues with bic.  To 
my knowledge, we're currently in a similar situation with cubic as we 
were with bic back then i.e. essentially no independent tests 
investigating its behaviour.

Of course I know Injong has posted some test results, but these are 
hardly independent as he's the author of both bic and cubic.  Have there 
perhaps been private tests carried out (e.g. by osdl) ?  If so, would it 
be possible to make them public ?  If not, well that would be good to 
know too.

My tests have been limited and showed no difference. It is worthy
of more discussion as to what is best. Could you rerun your tests?