Hey Gaurav,
Sad to note that no one replied.
To answer your question:
Most schools say a minimum of 2-3 experience is beneficial. Some schools say it is preferred but not mandatory. If you have a typical profile, I would say that 4 years or more would be ideal.
But if you are non-IT and have some really outstanding data for the rest of your apps, 2 years would be the best.
Higher experience always helps so they know that you have some experiences to share with in the classroom. But these days, some schools have started going young. Or so some surveys say. But I still recommend a minimum of 2.
Vineesh,
Just telling you what I know and think. I am not the expert.
