Computer Networks: NS Demo

Computer Networks - CMPSCI 653

NS Lecture Page

Slides presented in class: [PPT] - [PS]
Network model and parameters:
NS script: example.tcl - Class handout [ps]
Perl script to parse the NS trace file and extract packet loss information: get_stats.pl.
Results from running the following simulation: ns example.tcl 500 1234 700 0
- Aggregate queue size (instantaneous and cumulative average), dropped packets (instantaneous). Green curve is cumulative average starting at time 0. Blue curve is cumulative average starting at time 50 (ignores the transient):
  
  Graph generated using gnuplot with the script queue.gnu
- Number of packets in the queue of individual flows (TCP flows 1 and 2, instantaneous). Red flow starts at time 5. Green flow starts at time 10:
  
  Graph generated using gnuplot with the script window.gnu
- Average throughput of individual flows (TCP flows 1 and 2, cumulative):
  
  Graph generated using gnuplot with the script window.gnu
Perl script to run NS several times and gather some statistics (computes the sample mean and 95% confidence interval): runner.pl
- Results obtained by running the runner.pl script. Average queue size as a function of bottleneck queue capacity.
  
  Graph generated using gnuplot with the script avg_queue.gnu