Queuing Models in NS2

M/M/1 is a system with poisson arrival time, servicing exponentially and a queue of unlimited capacity and type of FIFO Queue. This is the simplest queuing system.  NS2 supports various distributions like pareto, exponential, constant, unifrom, etc to handle the network dynamics and metrics. So it is very easy to test the given network link to monitor a given queue using any of these queuing models. The listing 3 and 4 are monitoring the link when DropTail queue is used with a capacity of finite and infinite. Listing 13.3 uses infinite capacity and Listing 13.4 uses Finite capacity The output screen shot is shown below the scripts for further understanding
Listing 3 – M/M/1 Queuing Model #new Simulator creation set ns [new Simulator] #trace file creation for capturing the UDP data set tf [open out.tr w] $ns trace-all $tf
#setting the exponential distribution param set lambda 30.0 set mu     33.0
#creation of nodes set n1 [$ns node] set n2 [$ns node] #The queue limit is 1Lakh as the capacity is infin…

Tracegraph installation in Fedora 21

To install tracegraph (a software that handles the tracing automatically by specifying the trace file generated from ns2)

OS Used: Fedora 21 (64 bit)
Tracegraph version: 2.02

Download the tracegraph software from this link

Since tracegraph is a 32 bit software, you need to install all the 32bit libraries. The following packages that ends with .i686 are related to 32bit libraries

Steps to install
$] su
and press the root password
$] yum update
$] yum install ld-linux.so.2 libXext.i686 libXt.i686 libXp-devel.i686 
Still if tracegraph is not working, install these softwares too (this will also help in installing ns-2.35)
$] yum install tcl tk gcc-c++ libX11-devel libXt-devel libXmu-devel

To install Tracegraph
untar the software after copying it to your home folder (/home/pradeepkumar) in my case.
$] tar zxvf tracegraph202.tar.gz
$] cd tracegraph202
After the above step you need to set the LD_LIBRARY_PATH
Open the file /home/pradeepkumar/.bash_profile and give this line in the file
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/pradeepkumar/tracegraph202/bin/glnx86
and save the file and logout and login back.
$] ./trgraph 
This should pop out three windows, then tracegraph is installed successfully.

Since tracegraph is a very old software, there could be some bugs in the recent Operating Systems. So whenever, you open the tracefile, use the following command to open the files (Rather than using the File menu within tracegraph)

$] ./trgraph /path/to/file.tr


T S Pradeep Kumar

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