On Tuesday 16 September 2003 09:21, Kevin O'Connor wrote:
> Hi,
>
> I have a cable modem with a bandwidth capped upload rate. I'd like to
> prioritize packets going outbound according to the TOS header of the IP
> field. I've read through the LARTC Howto several times, and I think I have
> a good feel for the information it it. It also seems that what I'm trying
> to do is pretty straight-forward and common. Unfortunately, the HOWTO
> doesn't seem to have a good answer for this simple problem, nor have I been
> able work out how to do this from wading through a lot of other
> documentation.
>
> It appears that the pfifo_fast qdisc has most of what I want - prioritizing
> by TOS header. Unfortunately, it is a "work conserving" queue, and won't
> work with my cable modem unless I can artificially slow down the link.
>
> The tbf qdisc seems like it has the second part of what I want - an
> artificial upload cap. Unfortunately, it doesn't do prioritizing. I'm
> using just the tbf qdisc right now with decent results, but it still isn't
> exactly what I want - sometimes bulk connections will cause latency for
> interactive sessions and I find that my maximum upload rate is slightly
> impaired on bulk connections.
>
> So the question is, how do I successfully combine the above two qdiscs?
>
> Ideally, I'd like to have three queues (interactive, normal, and bulk) like
> pfifo_fast has, with maximum latencies (or queue size) for each of the
> queues (eg, 50ms, 100ms, 500ms respectively). And then prioritize the
> queues so that interactive data is always taken first and bulk data last.
>
> It would seem the htb qdisc has what I want. Unfortunately, the
> documentation (in both the howto and the htb website) all describe
> complicated scenarios where I need something much simpler. Also, I can't
> seem to find the answer to simple questions like - how do I set the maximum
> queue size (and/or maximum latency) for a qdisc that is a child of an HTB
> qdisc?
You can add a htb qdisc and 1 class. And attach the pfifo_fast to the class.
So the htb class will limit the traffic and the pfifo_qdisc will prioritize
the packets.
Stef
--
stef.coene@xxxxxxxxx
"Using Linux as bandwidth manager"
http://www.docum.org/
#lartc @ irc.openprojects.net
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