WiFiVL

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WiFiVL

• WiFi Virtual Laboratory
• T. Sturgeon, A. Miller, C. Allison
• University of St. Andrewshttp//wifi.dcs.st-andre
  ws.ac.uk

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Goals of WiFi Virtual Laboratory

• WiFi is an expanding area of interest
• Large increase in wireless network availability
• Can be a dry subject to learn from a textbook
• Provide environment for user to create a wireless
  scenario
• Capable of supporting a classroom of users
• WiFiVL should be accessible without any
  specialised software or previous programming
  knowledge

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Frame format
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CSMA/CA protocol
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Ns

• What is it?
• Ns is a discrete event simulator targeted at
  networking research
• Ns provides substantial support for simulation of
  TCP, routing, and multicast protocols over wired
  and wireless (local and satellite) networks.
• Who uses it?
• Researchers
• Teachers
• Why use it?
• Cheaper saves time and hardware costs
• Easy to set up 1-1000 hosts
• How to use it?
• Installs on Linux and Windows under Cygwin
• NS is driven by OTcl
• OTcl, short for MIT Object Tcl, is an extension
  to Tcl/Tk for object-oriented programming
• NS provides a trace of network events .tr, .nam
• Provides an animator to visualise results from
  the trace file (nam)

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Barriers to Using Ns for Learning

• Complicated Install
• Many dependencies
• Quite a few bugs
• Possible under Windows however Cygwin required
• Necessitates learning new scripting language
• OTCL
• Necessitates learning interpretation of trace
  files
• Trace files and NAM files provide results of
  simulation
• Many different keys in the trace format

for set i 1 i lt opt(nn) incr i set
WT(i) ns_ node i proc coord_proc a
return expr 10 a for set i 1 i lt
opt(nn) incr i WT(i) set X_ coord_proc
i WT(i) set Y_ coord_proc i WT(i) set Z_
0.0
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User Interface Form
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Point and Click User Interface
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Showing sensing range
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System Architecture
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OTCL Generation
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ActionScript 2.0 Task Scheduler

• Ability to run a task at a set time
• Schedules tasks based on their simulation time
  which is read from an XML file

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Resulting Animation
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Evaluation

• Core honours module in networks
• WiFiVL deployed to 3rd year university students
  2005/2006
• Analysis based on final exam results from 2003 to
  2006
• Compared distributions of results in the WiFi
  question in years 2003-2006
• Compared distributions of results in WiFi with
  the other questions from the same paper
• Summative statistics for the study

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Preliminary Results

• Number of students choosing a WiFi question has
  risen from 70 to 94
• Those who chose WiFi question recently
• Increased score for the question than previous
  years
• Highest mark achieved in the WiFi question
• Scores for poorer students rise along with
  overall performance of the year
• In upcoming semester users will be provided with
• Worksheet to complete
• Evaluation form
• WiFi had an average of 71 which compares to 67 58
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• Average 71(2006), 57(2005) 56(2003)
• Uptake 94 (2006), 69 (2005), 78(2003)

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Current Work

• Exposing the modular nature of this design
• Integration with other learning tools
• Revised format for configuring a scenario
• Web form, whilst highly accurate and efficient
  could be more user-friendly
• Exposing more of the Ns API
• Carrier sensing power
• Exposing more of the capabilities of NS2
• Could expand to wired scenarios to show
• Routing
• Queues..
• Integration with ELeGI made available as Grid
  learning service(s)
• Script Generation
• OTCL Generator released as an independent library
• Open System
• Try it out and give us some feedback

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Questions