Re: [LARTC] TCP Rate Control

[Stef Coene <stef.coene@docum.org>]

On Thursday 15 May 2003 19:41, Varun Varma wrote:
> Stef Coene wrote:
> > You mean something like the gred or red qdisc.
>
> The difference is RED drops the packets after they arrive basing it on
> the understanding that the TCP implementations would take this as a hint
> and slow down the transmission rates.
>
> Rate control on the other hand takes a more "hands on" approach to the
> problem. As Jose mentioned, ack pacing, window sizing etc...it actually
> exploits fundamentals in TCP flow control itself.
>
> > But I wonder if it will be a big different between "TCP rate contorl" and
> > plain old shaping.
>
> There are lot of comparisions on this. I don't want to get into a debate
>   here, since people from each group [rate control vs. queueing] feel
> very stongly about their stand.
But I'm still intested in the comparision :)

> Simply put, there are dozens of queueing disciplines, because some might
> "behave better" than other in some cases. I *feel* that rate control
> would work better in some particular cases, so I was interested in
> knowing if a rate control like implementation is available under Linux.
Not in the default linux kernel.

> >>Seems to be a patented "idea" in the USA, but I remember someone on this
> >>list talked not long ago about he waaas implementing something like this
> >>for Linux, from outside the USA. Check the archives for the message:
> >>Subject: Re: [LARTC] How far can TC go?
> >>From: Patrick McHardy <kaber@trash.net>
> >>Date: Sat, 29 Mar 2003 11:08:30 +0100
>
> Thanks for the reference...still need to check it out.
I already did :

Packeteer has various patents covering tcp rate control and everything else
they do, including the "idea" to look at upper layers to detect the type 
of traffic.
I live in germany so i don't really care that much about their patents 
(they had none in europe last time i checked). last summer i started 
implementing tcp rate control as qdisc for linux. i haven't worked on it for 
a couple of month now,  but if anyone wishes to participate i would be glad 
to dig out my source again. it is basically working, the remaining problems 
are mostly how to detect and handle interactive traffic.

Patrick

> About the patent thing...I know for sure that ack pacing has been
> published in paper before. Note: I am not suggesting how to circumvent
> this patent in any way. That said, I think it should be possible to work
> out other mechanisms, based around TCP flow control, which don't work
> the way Packeteer's patent works.
>
> If you google for "linux rate control", you come up with a link like:
>
> http://www.postel.org/pipermail/end2end-interest/2001-April/000701.html
>
> Which is a master's thesis, proposing another way to implement rate
> control.

Stef

-- 

stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.oftc.net

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