On Mon, Dec 17, 2001 at 03:20:51AM -0500, Mike Silbersack wrote:
> 
> (Moving over to -net, please remove -stable from any cc's)
> 
> On Mon, 17 Dec 2001, Thomas Zenker wrote:
> 
> > I allways wondered, why the initial slowstart window is set to one
> > (well some years I didn't look into the tcp code though). 9 years
> > ago I had to develope the firmware for a store&foreward radio
> > network, where I applied a lot of the ideas from the then net/2 tcp
> > stack.  The rtt in such a network is really horrible and packetsizes
> > have to be taken in account. Anyway the optimal initial window there
> > was 2. With a window of two there much more probability to get a
> > connection going, because you send two packets in the beginning,
> > if the first is lost, the receiption of the second one gets the
> > first one resent long before the timeout. Otherway round, if the
> > second is lost... the third is on its way already. With a intital
> > window of 1 the only recovery is by timeout. The argument against
> > bigger than two was (at least in my case) not to defeat the intention
> > of the slowstart.  Anyway, in tcp probably something between 2 and
> > 4 could be considered.
> >
> > Thomas
> 
> RFC 2581 suggests that 4 is a good value (well, not exactly 4, they have a
> formula which comes out to about 4 in most cases.)  I'm inclined to agree
> that something between 2-4 would be a good value for our non-local
> slowstart flightsize as well.  Maybe after 4.5 is released we can go look
> into it.  (It's too late to be changing stuff now.)
> 
> Mike "Silby" Silbersack

ok.

everybody can try this anyway:

sysctl net.inet.tcp.slowstart_flightsize=2


-- Thomas Zenker
   c/o Lennartz electronic GmbH
   Bismarckstrasse 136, D-72072 Tuebingen, Germany
   Phone:  +49-(0)7071-93550
   Email:  [EMAIL PROTECTED]

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