On Wednesday 06 August 2003 20:41, Patrick Turley wrote:
> > > The fact that the filters are metering traffic flows implies that they
> > > have are stateful. When using filters with egress queue hierarchies, it
> > > was my understanding that no state was needed since all they do is
> > > direct packets into classes. It sounds like my current understanding is
> > > quite wrong.
> >
> > I don't think the filters are statefull. If you use policers, you only
> > rate limit the filters. The filters itself have no idea about the
> > traffic flows.
>
> Then there are two further questions (the first of which I actually
> should have asked before):
>
> 1) When working with egress traffic control, filters are attached to
> classes. The documents I've read so far tell me that the ingress qdisc
> is classless so, on the face of it, filters shouldn't be useable at all.
> Please tell me which part of this I have badly misunderstood.
Ingress is indeed classless, but you can filters on it. It's not important
where the filters point to because there are no classes. But you can add
policers to the filters.
> 2) Since the filters themselves are, as you say, stateless, then it
> sounds like a "policer" is a separate object that's being created at the
> same time as the filter. Is there any other way to create a "policer"
> object, or do they only exist when attached to filters? When working
> with egress traffic control, can you attach policers to filters, and how
> would they interact with the classes?
You have to see the policer as a small tbf qdisc that exists on his own. If
you add the policer to a filter, all packets are "queued" in the policer and
throttled.
You can also use the same policer on different filters. So the packets from
different filters are "queued" in the same policer. To do so, you need the
tcindex option.
I will dig in my mail archive and put online on www.docum.org what I can find.
Stef
--
stef.coene@xxxxxxxxx
"Using Linux as bandwidth manager"
http://www.docum.org/
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