NS2 : Simulating Link State Routing

  The post provides the NS2 Script (TCL Script) to simulate a wired network using Link State Routing Protocol.

Execution of the Script

Network Topology in NAM

Data Transfer & Link Failure

Data Transfer through Alternate Path

Second Link Fails & Data Transfer through Alternate Path

Click here to download the NS2 Script.

NS2 : Simulating Distance Vector Routing

  The post provides the NS2 Script (Tcl Script) to simulate a wired network using Distance Vector Routing Protocol.

Execution of the Script

NAM Showing the Network Topology

Data Transfer in NAM

First Link Fails

Data Transfer through Alternate Path

Second Link Fails & Data Transfer through Alternate Path

Click here to download the NS2 Script.

NS2 : Simulating TCP in Wireless Networks

   This post provides the NS2 Script (Tcl Script) to simulate a wireless network using TCP.

Execution of the Script

Topology in NAM

Data Transfer in NAM

Click here to download the NS2 Script.

NS2 : Simulating UDP in Wireless Networks

   This post provides the NS2 Script (Tcl Script) to simulate a Wireless Network using UDP.

Execution of the Script

Topology in NAM

Data Transfer in NAM

Click here to download the NS2 Script.

OTcl Class Program

   OTcl refers to the object oriented extension of Tcl. It is used in Network Simulator (NS2). This post provides an example program involving OTcl Classes.

Program Execution

Click here to download the OTcl Program. 

Tcl Program to Find the Square of a Number

      This post discusses the Tcl program to find the Square of a Number. 

Program Execution

Click here to download the Tcl Program.

NS2 : Simulating a Network using SFQ Queue Management Algorithm

   In this post the NS2 Script (TCL Script) to simulate a wired network using SFQ (Stochastic Fairness Queuing) queue management algorithm is provided.

Executing the TCL Script

Topology in NAM

Data Transfer in NAM

   

Click here to download the NS2 Script.

NS2 : Simulating Multicast in Wired Networks

      In this post I have added the NS2 Script (TCL Script) to simulate multicast in wired networks.   

Executing the TCL Script

Topology Shown in NAM

Data Transfer in NAM

Data Transfer in NAM

Click here to download the NS2 Script.

NS2 : Simulating a Network using RED Queue Management Algorithm

   In this post the NS2 Script (TCL Script) to simulate a wired network using RED (Random Early Discard) queue management algorithm is provided.

Executing the TCL Script

Topology in NAM Animator

NAM Showing Packet Drop

Click here to download the NS2 Script.

NS2 : Simulating a Network using Drop Tail Queue Management Algorithm

   This post contains NS2 Script (TCL Script) to simulate a wired network using Drop Tail queue management algorithm.

Executing the TCL Script

NAM Animator Showing the Topology

NAM Showing Data Transfer 

Click here to download the NS2 Script.

NS2 : Wireless Simulation 2

   This post contains NS2 Script (TCL Script) to simulate a simple Wireless Network. The simulation involves wireless nodes which move from one position to another occasionally. 

Executing the TCL Script

Initial Node Position

Node Position after Movement

Click here to download the NS2 Script.

NS2 : Simulating Link Failure in Wired Networks

   In this post I have included the NS2 Script (TCL Script) for simulating link failure in wired networks. 

$ns rtmodel-at 1.0 down $n1 $n2
The code given above will fail the link between Node n1 and Node n2 at time 1.0.

$ns rtmodel-at 2.0 up $n1 $n2
The code given above will reconnect the link between Node n1 and Node n2 at time 2.0.

Executing the TCL Script

Simulated Network in NAM

Initial Traffic Flow Simulation in NAM

Link Between Node1 and Node2 Failed

 Traffic Flow through a Different Path

Link Between Node1 and Node2 is Up Again

Click here to download the NS2 Script.

NS2 : Simulating a Simple Wired Network Using TCP

   In this post I have added the NS2 Script (TCL Script) to simulate a Simple Wired Network using TCP (Transmission Control Protocol). 

Executing the TCL Script

NAM Window Showing the Network

NAM Window Showing the Traffic

  Click here to download the NS2 Script.

NS2 : Simulating a Simple Wired Network Using UDP

  

  This post gives the NS2 Script (TCL Script) to simulate a simple network using UDP (User Datagram Protocol ). The Shell command to execute the script is shown below.

Executing the script udp.tcl

NAM Window Showing the Simulation

Click here to download the NS2 Script.

Installing NAM on Fedora 17

  After installing NS-2.35 on Fedora 17 by calling the script ./install on the shell the following message is printed on the screen many often. "Please compile your nam separately". The message tells us that the NAM utility has not been installed properly. In order to install the NAM utility change the file xwd.c. 

The location of the file xwd.c is ns-allinone-2.35/nam-1.15/xwd.c. In the file xwd.c comment the following line of code as shown below.

// #include <X11/Xmu/WinUtil.h>

Save the file xwd.c.

Run the ./install script on the Shell again. NAM utility will be installed properly.

       

Installing NS-2.35 on Fedora 17

  Installing NS-2 on Fedora 17 only requires executing the ./install command on the Shell. But many often the Make process will fail. If the Make process fails then change the file ls.h.

The location of ls.h is the location of ls.h is  ~/ns-allinone-2.35/ns-2.35/linkstate/ls.h.

Open the file ls.h and change the code in line number 137.

The code in line line number 137 is  void eraseAll( ) { erase(baseMap::begin( ), baseMap::end( )); }  

Change it into the code given below,
void eraseAll( ) { this->erase(baseMap::begin( ), baseMap::end( )); } 

After making the change save the file ls.h.

Now again run the script ./install in the Shell. The installation will be complete.

Xgraph for plotting in NS-2

After running your NS-2 program you will have a trace file as output.

Let us assume the name of the output file is "trace1.tr"

The trace file might look like below

+ 1             0 2 cbr 210 ------- 0 0.0 3.1 0 0
- 1              0 2 cbr 210 ------- 0 0.0 3.1 0 0
r  1.00212  0 2 cbr 210 ------- 0 0.0 3.1 0 0
+ 1.00212  0 2 cbr 210 ------- 0 0.0 3.1 0 0
+ 1.055      0 3 cbr 210 ------- 0 0.0 3.1 0 0

I am not explaining the meaning of the trace file. Instead I am giving instructions to use xgraph to draw a graph involving data extracted from the trace file.

To use xgraph we need 2 columns of data. The Unix command called "cut" is used for this purpose.

Open terminal and type the following commands

###############################

    cut  -d  " "  -f  2  trace1.tr  >  file1

    cut  -d  " "  -f  6  trace1.tr  >  file2

    paste      file1     file2    >   output

    xgraph   output

###############################

This will extract columns 2 and 6 and then draw a graph using the xgraph utility.

 
 for "cut" keyword -d specifies the delimiter between columns.
 Here the delimiter is white space ("  ").
 -f specifies the column number of the data to be extracted.