Hey Piyush

Since you have not specified which exam is this rank of, I can only consider the all India examination- JEE. So, accordingly, even if these ranks are of mains or advanced, I am sorry but you cannot get any of the seats of your desired branch, i.e., CSE/IT. Also, it is unlikely that you may get any other branch in any of the NITs or IIITs. Thus, you should start  looking for other options indeed. At this rank, it is unlikely that you may get CSE or IT in any top ranked private college as well. But don't you lose your hopes. Check for the college predictor link to get more options available- https://engineering.careers360.com/jee-main-college-predictor

I hope this helps you. Feel free to ask any other queries.

All the best!!