Abstract: The Wifi Virtual Laboratory development was started ...

fawnhobbiesSoftware and s/w Development

Jul 4, 2012 (5 years and 15 days ago)

224 views

ActionScript allows for much more dynamic content and greater control over the
display of information and media. A problem with ActionScript is the lack threading
or timing capabilities. Hence, telling the program that a packet needs to be sent in
0.003 (s) is quite difficult. The time base was taken by using each frame as the tick
of a clock. Each new frame incremented the current time by a very small amount.
Once in a new frame any events in the simulation that were to be run in the following
frame would be added to the tail of a queue. As each new frame is displayed the
queue is checked and if any events are present they are removed and executed.
Abstract: The Wifi Virtual Laboratory development was started in summer 2005. It is designed
to allow students to learn about wireless networks by creating a simulation and seeing the
results. The user defines a simulation using a HTML form. These settings are then converted
into OTCL which is run on the NS2 network simulator. The result of a simulation is a file with
details of the transport and MAC layer events. This information is converted to XML and then
displayed using ActionScript 2.0 in Flash MX.
This project makes
the power of the
NS2 simulator
accessible for
students learning
about wireless
networks.
NS2 is a network
simulator developed
at UC Berkeley and
is written in C++.
Simulations are
specified in Object
TCL.
NS2 executes the
script and outputs a
file listing network
events.
The overhead of
learning OTCL
discourages the use
of NS2 in
undergraduate
courses.
In this project a
graphical web
interface for the
generation of OTCL
scripts has been
developed.
The resulting
simulation can be
viewed in any web
browser rather than
the Linux-only NAM
player program.
Tomcat
Data from HTML
form about the
simulation sent to
servlet
OTCL script
generated
from HTML
data
NS2
NAM – Trace of
every network
event
Convert
NAM file to
XML
Flash
ActionScript
displays the
results to the
user
0
n
Flash frames animated at 50 per second
XML
trace file
Calculate
simulation time
based on frame
number
Found event
to animate at
this time.
Animation execution
queue
{tommy, alanr, ca } @dcs.st-andrews.ac.uk