After facing problem in web installer (due to internet connectivity like all other Indians) I tried and found a method to download offline installer for Visual Studio 2015. You can read that article here.
Not after some time of writing this article some of my readers notified me that Microsoft has released a ISO file for offline installation to no need to follow any process now. I thought WOW that’s great. But everything was not so great because when I tried installing my all new Visual studio 2015 Enterprise using ISO then I found there are something to take care off to install it.