[Gllug] Bandwidth shaping

Simon Stewart sms at lateral.net
Wed Apr 3 11:08:53 UTC 2002

On Wed, Apr 03, 2002 at 11:36:49AM +0100, Rev Simon Rumble wrote:
> I'm trying to get my head around bandwidth shaping.  It's really doing
> my head in.
> Okay so it seems you can only control outbound traffic and the aim of
> any shaping algorithm is to get the packet queuing to happen in a
> queue over which you have control.
> So would it be possible to use a loopback network connection to begin
> controlling inbound bandwidth?  Alternatively, if you have a machine
> running as a router between your computer and the Net connection,
> could you get it to shape the incoming traffic?

Simon, you need to look at the ingress packet filter if you're keen on
shaping incoming traffic. It's not too bad to get to grips with, and
should do what you want it to do (though shaping _incoming_ traffic is
a lot harder than shaping outgoing traffic, for obvious reasons)

One caveat is that it really works best on a 2.4 kernel, so if you're
lairy of that then watch out (I know that you're okay with using one,
but some of the other people on the list might still have their
reservations about it) Indeed, getting the ingress filter to work on
2.2 was a real PITA --- I gave up and went through the pain of
rewiriting the firewall in the end, cos that was a relatively trivial
exercise and provided additional benefits[1]
> I don't think I'm the only one who has little interest in controlling
> outbound bandwidth and lots of interest in ensuring I can still ssh
> into my machine even though a big download is occurring.

The traffic shaping HOWTO at http://lartc.org/ contains an example
script to do just this (at least, prioritise interactive sessions at
the expense of "bulk" downloads) if my memory serves.



[1] Slimmer firewall config, stateful filtering, etc.

And tomorrow will be like today, only more so.
		-- Isaiah 56:12, New Standard Version

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