6. Next screen will ask for your Internet connection type keep it as "Direct connection" and click next and in next screen choose one site to download the packages and click next.
7. In next screen Cygwin will allow to select the packages you want to install
8. Uncheck the option "Hide obsolete packages" then click on "view" button till the word "category" changes to "Full"
To install NS2 you need to select and install following packages:
To select a package search the package name and click on word "skip" this will change it to version number of the package. Do this for all above packages and click next to start download and installation
9. Once installation is complete create desktop icons if you need.
NOTE: If you missed any package while installing Cygwin first time you can install it by running the setup.exe again and selecting the package in step 8.
10. Cygwin installation is complete now you can run Cygwin from desktop and see its interface.
