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Re: PRIO example



On Thursday 04 January 2001 18:44, you wrote:
> > I have set up some test for DiffServ and it is working great for link
> > sharing with CBQ.
> > Now I try to use PRIO scheduler instead of CBQ to share the link and make
> > a EF class and a BE class. I use the example from iproute.
> >
> > I do not get the desired result.
> >
> > How can I use this setup and managed to get enough bandwidth to my EF
> > class?
> >
> > The PRIO scheduler is not able to make classes. What is then the
> > difference of the children I make for EF and BE compared to when I make
> > classes for this with CBQ?
>
> Classes (by default 3) are automatically created when you install the
> "prio" qdisc. If you want a different number of classes, use "bands N"
> option, and N classes will be created with the minor part of the classid
> from :1 to :N. Due to a bug you can't list these classes (tc segfaults),
> but their presence can be confirmed by QoS measurements.
Ok

I have tried to use RED for the BE class and TBF for the EF class. That 
showed up that the BE class used to much bandwidth with the values I used for 
limit, max, burst etc. How can I compute the bandwidth I am taking, with the 
values I use for this parameters?

How much have the priorities I am using affecting the result? 
E.g :
$TC qdisc add dev $DEV parent 2:2 red limit 60KB\
    min 15KB max 45KB burst 20 avpkt 1000 bandwidth 10Mbit\
    probability 0.4
 
$TC filter add dev $DEV parent 2:0 protocol ip prio 5\
    handle 0 tcindex mask 0 classid 2:2 pass_on        

Priority 5..

A also does not now what it mean to pass the parameter [pass_on | 
fall_through].
What's the meaning with this?

Usage: ... red limit BYTES min BYTES max BYTES avpkt BYTES burst PACKETS
               probability PROBABILITY bandwidth KBPS [ ecn ] 

If I use an 10Mbit switched Ethernet, what should be the best parameters 
values over for RED for not making the BE to use to much bandwidth so it is 
some left for my EF class?
The "bandwidth KBPS" parameter, is this the value of the physical link or 
what I will give to my class?

When I use TBF for both the EF class and BE class the results are better, but 
not as good as for CBQ.
Is CBQ better to use?


> I don't have one available, but there are lots of them floating around on
> the web.

I have searched, but it seems like it hard to find some examples other than 
that which followed with iproute...

Best regards
-- 

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Petter Larsen
Institutt for informatikk,
Universitetet i Oslo

sveinpe@ifi.uio.no
http://www.stud.ifi.uio.no/~sveinpe

Linux is best..:-)

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