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NS-2 Tutorial

COMP 7810 09R2

University of ManitobaMarch 4, 2009

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Goal and Outline

Goal of this tutorial

Lead you to get started using NS-2

Outline

Introduction - Whats NS?

Steps in Using NS-2 (through examples)

Development and Your Project

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Whats NS?

NS is a packet-levelsimulator

Started with Keshavs REAL in 1989

Been revised in Berkeley, then others

Overview

Major engine (network components) written in C++

User-interface is tcl script

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My First Tcl Script

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Test it out!

Go to

http://www.cs.umanitoba.ca/~yliu/TEACH/NS

2/TUTORIAL

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My First OTcl Script

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NS-2 Simulated Components

Protocols

TCP, UDP, DCCP, SCTP, TFRC, Wi-Fi, etc.

Network model

Nodes, links, topology, channel schedulers, buffer

management, etc.

Traffic model

Applications: FTP, CBR, MPEG, etc. Traffic traces

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NS-2 Simulated Components (II)

All implemented by students/researchers like

you and me

Each release has a few more contributed

components added

Many are still being developed

Well documented steps to use and to add to

NS-2

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General Steps In Using NS-2

Obtaining NS-2 (made available for you)

Writing an OTcl script. E.g., a.tcl

Run the simulation. Just type ns a.tcl

Post-process the trace generated

Plot graphs and include in your papers

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Obtaining NS-2

Available to you here in CS

Linux version 2.33 installed on neram-02 (a

networks lab Linux machine)

Each student is given a separate complete

copy of NS-2

Email me if you dont know how to access yours

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Obtaining NS-2 (for your home PC)

Available for both Linux and Windows

For Windows, you need VMware or cygwin

For Linux, install all-in-one package requires only

four commands tar xzvf ns-allinone-2.33.tar.gz

cd ns-allinone-2.33

./install

source setup.csh (Note this script was written by our systemadmin Gilbert, you may need to copy it over and customize it a little bit)

You are ready to go

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Writing An OTcl Script

Use NS-2, take a look at ns-simple.tcl

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Writing An OTcl Script (II)

Add to NS-2 Write a new network layer component

Write a new transport layer protocol

Write a new application Steps

Writing new components in .cc and .h (often free

implementations are available)

Add to existing header files in package

Add to Makefile and re-compile

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Add To NS-2

Step-by-step instructions for a few examples

available in NS by Example from WPI

On Transport, Application, and Network Layers

respectively

Web site

http://nile.wpi.edu/NS/

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Run The Simulation

Plug in the trace file names

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Run the Simulation to Collect Traces

Entire packet level event trace dump to file

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Post-Process the Trace Generated

Through scripting languages such as Perl,

awk, (ba)sh (shell scripts)

Or spread sheet such as Excel

See example ns-simple-trace.tcl to generate

trace out.tr

Perl and awk combined to produce jitter.txt

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Plot the Graphs

Gnuplot, very handy tool to give nice graphs

See example gp, a Gnuplot script that I

wrote

The generated .ps file can be easily added to

LaTeX for paper / report writing

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Development

Editor (you need a comfortable way to edit

files under Linux)

Vi, Emacs, pico, what else do people use?

Make

A very simple utility to automate compilation

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Your Course Project

Some tools to play with

OTcl, editor, make, perl, gnuplot

nam to avoid (an animator not essential to

simulation)

Need to add to NS-2?

Search for existing implementations on the net

first Have fun!