NOC no longer exists in Dubai
It is all based on education and salary now
limited contract will give an employer a 6 month ban if they leave before 2 years however most contracts are unlimited therefore no ban
Providing you have a high school diploma ( Need to earn more than 8000) or Bachelors need to earn more than 12000 then no ban
Rules on Ban in UAE are much softer than what they were in history. Anyone, almost, can change a job after having completed 1 year in contract. There are few fine details such as Limited or unlimited contract and educational level etc. But its cake walk in comparison to past.
In case you have a ban, new employer pays a fee to the government and gets it removed. I wouldn't believe it few years back. But now, its happening. WLO had put certain conditions for UAE to fulfill and free manpower movement was one of them.
I just started a job in Dubai! and the rules are similar here, you have to either be let-go from your position, or wait. however i believe its only 6 months not 2 years?