[altq 293] Re: Ingress traffic shaping?

[Kenjiro Cho <kjc@csl.sony.co.jp>]

Luigi, Glad to have you on the list.

Luigi Rizzo wrote:
> > OK, I can see how the above fits into place, but any suggestions - if our main
> > link is 1024kbs, what we should run AltQ at (and again, if the main link is
> > 2048kbs)? - Will this simple idea of "slowing" AltQ down, actually work? (i.e.
> > allow us to set acheivable limits for incoming TCP in certain clases?) - I
> > realise it's in the realms of a potential "simple fix" for a complex problem
> 
> i suppose in this case you just set the out port on the FreeBSD box
> to 512k so the queue will build up with the incoming traffic.

If Karl's question was what is the recommended shaper rate for
1024Kbps, we don't know.  90% of the link rate would be ok but we
don't have enough experience to claim it.

> Somebody (Julian specifically, but the idea has been in the air for
> some time) suggested that to limit incoming TCP traffic you should try
> to shape outgoing ACKs. Not easy, requires per-flow state, etc.etc.
> but it might be the way to go for slow links.

There is a commercial product called packeteer using that technique.
http://www.packeteer.com/

-Kenjiro