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…

xgraph Error (dialog.c)

If you are installing ns2 allinone package in fedora or ubuntu or any other linux, all the packages will be installed successfully. Occasionally the recent distributions of Linux flavors failed to install xgraph.


The possible error you may get is [dialog.o] error,


  1. Open the file dialog.c which is available under the folder xgraph-12.1/ (this is in my case)
  2. Find out the function getline() (will be at two places), usually line number 780 and 891 or 889, replace getline() function to newgetline() (at the both the places)
  3. save the file and at the prompt give ./configure
  4. give the command make
  5. If there are no errors, xgraph will work now..

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