tcp troughput weirdness

[Dan Nelson]

In the last episode (Jul 12), David Malone said:
> > did the trick! now can someone remind me what inflight does? and
> > could someone explain why increasing sendspace alone did not do the
> > trick? (i had it at 64k, which got things better, but not
> > sufficient).
> 
> TCP inflight limiting is supposed to guess the bandwidth-delay
> product for a TCP connection and stop the window expanding much
> above this. It's a pretty neat idea for DSL links that often have
> huge buffers at the far end, where inflight limiting can prevent
> delays to interactive traffic.
> 
> However, some of the guys I know that work on TCP dynamics reckon
> that they can they can come up with situations where inflight
> limiting will break. Unfortunately, I haven't had time to talk
> this through with them. I guess you may have found one of those
> situations ;-)

You might want to apply the patch at the bottom of
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/75122 ; without it, new
connections get a random initial bandwidth.

-- 
	Dan Nelson
	dnelson at allantgroup.com