Steps for conducting the experiment

General Instructions

Follow are the steps to be followed in general to perform the experiments in Advanced Network Technologies Virtual Lab.

1. Read the theory about the experiment
2. View the simulation provided for a chosen, related problem
3. Take the self evaluation to judge your understanding (optional, but recommended)
4. Go to the exercises section, choose a problem, and carefully read the problem description
5. Write a script (or make necessary changes) to simulate the desired scenario in the code editor just below the problem statement
6. Click on the 'Run' button to execute the simulation script
7. Simulation with ns2: If the simulation was successful, and was instructed to create a trace file, contents of the trace file would be displayed in the area below the 'Run' button
8. Simulation with ns3: If the simulation was successful, output of the program would be displayed in the area below the 'Run' button
9. A trace file generated as a result of simulation with ns2 could be used for certain kind of analysis, which would be discussed in a later section

Experiment Specific Instructions

1. The problem statement is presented in the 'Exercises' page, which you have to simulate with NS2.
2. Simulate the code given in the 'Exercise' page and find out the no. of formation of Piconet and Scatternet.
3. Set the global configuration parameters for Bluetooth network.
4. Configure the nodes:

$ns node-config -macType Mac/BNEP
set btRouting AODV 
set val(nn)     32

set P 0.5	;# 0.3333 ~ 0.6667
set K 7
set delta 5
set lastRoundTries 6

set trafficStartTime 90
set collisionRng 22.4	;# set to 0 to turn collision off.
set rpAlgo	DRP
set tsniff	256
set seed 1634
set tracePageScan off

5. The following line of code shows the number of nodes in the network:

set val(nn)     32

6. Run the simulation by varying the number of nodes
7. After the simulation of the code is over, scroll its output, and go to the end. There you can find information on the number of master, slave, master-slave and slave-slave nodes in the network. Note down these values -- for each value of the total number of nodes -- in a text file.
8. Compute the piconet density and slave degree from the above obtained values.
The UCBT Bluetooth extension for NS-2, which we have used here, generates a lot of informative messages when a simulation is executed. To preserve bandwith, and reduce the delay, over the Web, we have disabled most of such messages.

Trace File Analysis

A simple tool has been provided as part of this lab to analyze the trace files generated after simulation with ns2. A summary of the available options, and usage guide is given below.

Features List

Following is a list of functionalities provided by the Trace Analysis tool:

• Trace file formats: Following trace file formats are being supported:
  • Wired
  • Wireless (new format)
  • Satellite -- currently redirects to wired mode
  • Mixed -- when both wired and wireless connections are present in the simulation
• General Statistics: To provide some common statistics about the simulation being run. Currently displays only the simulation duration.
  • Inputs: None
  • Output: Text
• Average Throughput: Computes total # of bytes received by a node over the entire simulation duration
  
  • Inputs: Node #
  • Output: Number
• Bytes Received: Plots cumulative count of bytes received by a node over the entire simulation duration
  
  • Inputs: Node #; for wireless scenario, trace levels (AGT, MAC, RTR)
  • Output: Graph
• End-to-end Delay: Plots the end-to-end delay delay encountered by packets while moving from a source node to the destination node
  
  • Inputs: Source node #, destination node #, scaling factor [optional] -- scaling factor helps to amplify the y-axis values
  • Output: Graph
• Packet Retransmissions: Plots # of retransmission(s) of a given packet occurs between the source and destination nodes
  
  • Inputs: Source node #, destination node #
  • Output: Graph
• Hop Count: Plots the # of hops traveled by a packet to reach the destination node from the source node. It counts the destination node as well.
  
  • Inputs: Source node #, source port #, destination node #, destination port #
  • Output: Graph

Limitations

1. For analyzing the problems in the "Satellite Networks" experiment, please use the Wired mode of analysis
2. Analysis of trace files for mixed mode of simulations (wired & wireless) is not supported currently
3. Outputs produced do not necessarily have accuracy for scientific publications. In particular, the plot of hop counts may vary a bit from the original count (in wireless mode) in cases when a packet has been forwarded to more than one node.
4. The tool currently allows only a single instance of a given type of plot. For example, this doesn't let you plot end-to-end delays between multiple (source, destination) node pairs