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…

Installing Windows, Linux and Yosemite inside Mac

This post tells you how to install Windows and Linux within Macintosh Machine (Yosemite)
Base OS: Yosemite
Other OS: Windows 8.1, Fedora 21 (Linux Mint 17.1 also)
Machine used: Mac Mini (Mid 2013)

Installing Yosemite

Step 1: Install Yosemite (If you have mavericks, download it from the Store and install it)

Installing Windows 8.1 

  • Open Boot Camp and select "Install Windows 7 or later" and also select "Download the support Softwares for Windows 7 or later", You need to provide a FAT partitioned Pen Drive (This wil be another pendrive other than the Windows 8 Boot Pen Drive, if you dont have any other pendrive, leave this step, after installing Windows you may come back and download the support softwares) and Click Next.
  • Now Mac will ask for partitioning your hard disk into two (Select atleast 50GB for installing Windows).
  • Reboot and Press the "Option" button and select Windows (You have to insert the USB that boots Windows 8.1)
  • Everytime when Mac restarts, you need hold the "Option" key to select the Windows OS.
  • Once Windows installed, Open the FAT Pen Drive with the support software (There will be folder called Bootcamp, open it and click the setup.exe and wait till all the drivers are installed and you can see a bootcamp icon in the bottom right task bar)
  •  Thats it.... (Hold the "Option" Key everytime if you want to select the concerned OS (Mac or Windows)

Installing Linux (Fedora 21 or Linux Mint 17.1 or Ubuntu 14.04.1) 

  • Make a bootable Pendrive with either of these three OS (in my case, i used Fedora 21 64 bit)
  • You need to make the bootable pendrive that suits Mac... Here are the steps
  • Copy the Fedora-xx.iso file in Desktop and issue the command 
  • $] hdiutil convert -format UDRW -o ~/Desktop/fedora21.img ~/Desktop/Fedora-xx.iso
    $] diskutil list
    Select the appropriate disk (in my case/dev/disk2) and make it bootable by the following command
    $] diskutil unmountDisk /dev/disk2 
    $] sudo dd if=~/Desktop/fedora21.img.dmg of=/dev/rdisk2 bs=1m
    (you can use /dev/rdisk2 for faster operation, else you can use /dev/disk1, also remember i did all my work at the Desktop so, i put ~/Desktop, 
    in your case you can change the alternate location where you stored the iso and img) 
    $] diskutil eject /dev/disk2 
  • Install rEFInd for Mac  http://sourceforge.net/projects/refind/files/latest/download
  • To install rEFInd, unzip rEFInd and open the folder, Open Terminal and drag the install.sh from the rEFInd folder and drop it to the Terminal and press Enter... 
  • Open "Disk Utility" by pressing the "Command+Space Bar" and shrink the boot space for Linux (20GB is the minimum recommendation I suggest). You can see the picture below. (The first image shows the unshrinked partition and the second image shows after shrinking)
Linux in Mac Mini
Linux in Mac Mini

Linux in Mac Mini
Linux in Mac Mini
  • Once done, Shutdown the machine and then Power ON. 
  • Select the Linux OS from FAT Partition and boot and install Fedora 
  • if You get the following error, "sda may not have enough space for grub2 to embed core.img" during the partition, you can reboot the machine and Hold the Option key and then select the Fedora Linux.
Once everything is installed, you can continue to boot Mac (Yosemite) or Windows 8.1 or Fedora 21..... So all three OS in a single Machine..... 

Raise your queries through the comment section below..... :)

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