Re: want to randomly drop packets based on percent

From: George Nychis
Date: Mon Apr 17 2006 - 13:05:27 EST




Stephen Hemminger wrote:

On Mon, 17 Apr 2006 18:30:51 -0400
George Nychis <gnychis@xxxxxxx> wrote:



Stephen Hemminger wrote:



On Mon, 17 Apr 2006 03:38:33 -0400
George Nychis <gnychis@xxxxxxx> wrote:





Hey,

I'm using the 2.4.32 kernel with madwifi and iproute2 version 2-2.6.16-060323.tar.gz

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

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?

Thanks!
George
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