[ns] problems working with RAMP (RApid Model Parameterization)
fumi at wgserve.de
Wed Apr 20 08:53:15 PDT 2005
i just developed a flexible traffic-generator which enbeds Otcl to
define the scenario, specify the characteristics of the traffic and
generate the actual traffic by populating an abstract traffic stucture.
I am now going to compare my generator with others. I found RAMP
(bundled with ns2) which provides a set of differend scripts to
parametrerize a simple http (and ftp) model. I first tried the examples:
.../tcl/ex/empweb/isigen.tcl.../tcl/ex/empweb/simple.tcl. I found that
there are many typing errors to fix before the scripts work (only the
simple example works fine (and out-of-the-box) with version 2.26 of ns).
additionally there are missing cdf-files :(. After solving these
problems i found that many model-variables described in the
corresponding RAMP-paper as CDF-defined are hardcoded constants or
modeled by cdf-files defining a constant distribution. is there a way to
get the mentioned missing files? why are so many model-variables modeled
constant? has anybody already tried tu run the examples? is it right
that ramp only maps a real-world scenario (of cause only its traffic)
into a simulation, without any possibility to use the resulting
distributions for other scenarios?
After this i tried to generate my own cdf-files using the ramp-scripts.
There, too, many patches were needed to get it work. I found that the
scripts, especialy "outputCDF" needs more that much memmory. for a short
tcpdump-slice of about 3 days it needs more then 3GB of memmory. is this
normal? is there a more improved cdf-calculator? has anybody already
generated his own cdf-file set?
it would be great if anybody could answer at least a few questions....
i already tried to contact Kun-chan Lan directly... but sadly with no
success :( (he didnt answer at all) ...
another big question: which traffic generators are you working with?
it would be great to hear about to (perhaps) compare these
traffic-generators with my new one as well..
thanks a lot..
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