Re: want to randomly drop packets based on percent

[George Nychis <gnychis@cmu.edu>]

Stephen Hemminger wrote:

> O
>  
>
> > > > > > I wanted to insert artificial packet loss based on a percent so i found:
> > > > > > network emulab qdisc could do it, so i compiled support into the kernel 
> > > > > > and tried:
> > > > > > tc qdisc change dev eth0 root netem loss .1%
> > > > > >       
> > > > > >
> > > > > >            
> > >            ^^^^^^
> > >
> > > You need to do add not change. Add will set the queue discipline
> > > to netem (default is pfifo_fast).  Change is for changing netem parameters
> > > after it is loaded.
> > >
> > >
> > >
> > >      
> > bahhh I see... the wiki has "change" instead of add.  Now i'm running 
> > into another problem, I have an XCP qdisc that I have already added via:
> > tc qdisc add dev ath0 root xcp capacity 54Mbit size 500
> >
> >    
>
> Wiki reads as a set of examples.  First uses, "add" after that "change".
>
>
>  
>
> > therefore when I also try to incorperate loss:
> > tcq disc add dev ath0 root netem loss .1%
> >
> > I get:
> > RTNETLINK answers: File exists
> >
> > Is it possible to use two qdiscs on the same interface?
> >
> >    
>
> No, but netem is "classful" so you can put xcp inside netem.
> Look at the token bucket example on the wiki.
>
>  
Sorry, I was looking at the LARTC guide, completely skipped over the 
blatently obvious block of commands you were pointing me too :P

Thanks!
George
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