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…

Installation of Network Simulator (NS2.35) in Mac OS

Installing NS2 in Mac OS is always a tougher task. Setting and configuring so many config files, etc.
But the latest version of NS2 (ns-2.35) is easily installing under Mac OS

OS Taken here is Mac OS 10.6 (Snow Leopard)
NS Version is ns-2.35 RC8

Prerequisites: Mac OS should be installed with the developer pacakge called xcode
with the help of Xcode only, all development modules can be handled.

So, the first step is to install the xcode, Download Xcode from this link http://developer.apple.com/xcode/

Download the ns-allinone-2.35 rc8 for installation, Download from http://www.isi.edu/nsnam/dist/release/RC8/

1. Install Xcode
2. Unzip or untar ns-2.35 using the command "tar zxvf ns-allinone-2.35-xxx.tar.gz" (without quotes)
3. The ns-2.35 configuration files contains  the path to xlibdir and xincdir, so you need not include the path for those directories.
4. kindly ensure that the path to xlibdir and xincdir are installed on your Mac OS(Xcode)
5. execute the command ./install inside the directory (~ns-allinone-2.35-xxx/) (use terminal to install) .
6. Once installed successfully, the path setting information will be provided to you. copy those informations and put it in a file called .profile or .bash_profile (please note that there is a dot in these files)

in my case, this is the path information (include the following line in the .profile file)

export PATH=$PATH:/Users/VIT/Downloads/ns-allinone-2.35-RC8/bin:/Users/VIT/Downloads/ns-allinone-2.35-RC8/tcl8.5.8/unix:/Users/VIT/Downloads/ns-allinone-2.35-RC8/tk8.5.8/unix

and also one more path called LD_LIBRARY_PATH
export LD_LIBRARY_PATH= <paths>

7. finally execute the command "source .profile" (wihtout quotes) and logout and login back.

open the terminal and type ns (you will get a % symbol indicates that the ns2 is installed successfully)
type nam and you can see a animation window is popping out.
(thats it)

if you want to install ns2.34 and earlier versions in Mac OS, then the above method will not be suitable for you. you need to include the
xlibdir and xincdir path in all the config files of ns2
and then proceed with the above steps..

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