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<div class="moz-cite-prefix">I haven't internalized this yet, but my
instantaneous reaction is:<br>
<ul>
<li> a radar screen is something people have been educated to
understand, so that's cool, and over time, plotting the time
taken for something against the load in somethings is what
capacity planners expect to see: "_/"</li>
</ul>
<br>
--dave<br>
<br>
On 18/04/16 06:48 PM, David Lang wrote:<br>
</div>
<blockquote
cite="mid:alpine.DEB.2.02.1604181539160.13992@nftneq.ynat.uz"
type="cite">On Mon, 18 Apr 2016, Dave Taht wrote:
<br>
<br>
<blockquote type="cite">I have been sitting here looking at wifi
air packet captures off and
<br>
on for years now, trying to come up with a representation, over
time,
<br>
of what the actual airtime usage (and one day, fairness) would
look
<br>
like. Believe me, looking at the captures is no fun, and (for
example)
<br>
wireshark tends to misinterpret unreceived retries at different
rates
<br>
inside a txop as tcp retries (which, while educational, makes it
hard
<br>
to see actual retries)...
<br>
<br>
Finally today, I found a conceptual model that "fits" - and it's
kind
<br>
of my hope that something already out there does this from
packet
<br>
captures. (?) Certainly there are lots of great pie chart tools
out
<br>
there...
<br>
<br>
Basically you start with a pie chart representing a fixed amount
of
<br>
time - say, 128ms. Then for each device transmitting you assign
a
<br>
slice of the pie for the amount of airtime used. Then, you can
show
<br>
the amount of data transmitted in that piece of the pie by
increasing
<br>
the volume plotted for that slice of the pie. And you sweep
around
<br>
continually (like a radar scanning or a timepiece's pointer) to
show
<br>
progress over time, and you show multicast and other traffic as
eating
<br>
the whole pie for however long it lasts.
<br>
<br>
conceptually it looks a bit like this:
<br>
<br>
<a class="moz-txt-link-freetext" href="http://blog.cerowrt.org/images/fairness.png">http://blog.cerowrt.org/images/fairness.png</a> (I borrowed this
graph
<br>
from
<a class="moz-txt-link-freetext" href="http://www.webdesignerdepot.com/2013/11/easily-create-stunning-animated-charts-with-chart-js/">http://www.webdesignerdepot.com/2013/11/easily-create-stunning-animated-charts-with-chart-js/</a><br>
)
<br>
<br>
Another way to do it would be to have the pie represent all the
<br>
stations on the network, and to have the "sweep hand" jump
between
<br>
them...
<br>
</blockquote>
<br>
does it really matter how much data is passed during the timeslice
as opposed to just how much airtime is used? (and there will be a
large chunk of airtime unused for various reasons, much of which
you will not be able to attribute to any one station, and if you
do get full transmit data from each station, you can end up with
>100% airtime use attempted)
<br>
<br>
I would be looking at a stacked area graph to show changes over
time (a particular source will come and go over time)
<br>
<br>
I would either do two graphs, one showing data successfully
transmitted, the other showing airtime used (keeping colors/order
matching between the two graphs), or if you have few enough
stations, one graph with good lines between the stations and have
the color represent the % of theoretical peak data transmission to
show the relative efficiency of the different stations.
<br>
<br>
<br>
While the radar sweep updating of a pie graph is a neat graphic,
it doesn't really let you see what's happening over time.
<br>
<br>
David Lang
<br>
<br>
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<br>
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<br>
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<br>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
David Collier-Brown, | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
<a class="moz-txt-link-abbreviated" href="mailto:davecb@spamcop.net">davecb@spamcop.net</a> | -- Mark Twain
</pre>
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