Yes, you can get a seat in IPU with a 20k general rank if you have a defence quota. The defence quota gives you a big advantage as 5 per cent seats are reserved. You might not get top colleges like USICT, but mid-tier ones are possible. Your chances depend on the course and counselling round. So yes, you have a good chance to apply in all rounds to improve it. For information, just visit https://engineering.careers360.com/articles/ipu-cet-reservation-criteria .