tcp troughput weirdness

Noritoshi Demizu demizu at
Tue Jul 12 10:21:24 GMT 2005

(I am sorry if you have received this e-mail.  I'm resending this
 because it seems the previous one was lost.)

> TCP inflight limiting is supposed to guess the bandwidth-delay
> product for a TCP connection and stop the window expanding much
> above this.

(Just to clarify..)
TCP inflight limiting has a dedicated variable "snd_bwnd".
And min(tp->snd_wnd, tp->snd_cwnd, tp->snd_bwnd) limits
the amount of data to be sent.

> 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 ;-)

I experienced such situations with DragonFlyBSD.  I put examples
where inflight limiting reduces throughputs at the following pages.

Sorry, all senders in those examples are DragonFlyBSD.

Noritoshi Demizu

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