ما هي الأنواع الثلاثة من ENA؟

Could you kindly elaborate on the three distinct types of ENA? I'm particularly interested in understanding the characteristics and functionalities of each type. Would you mind providing a brief overview of each, highlighting their unique features and how they contribute to the overall ENA framework? Additionally, it would be helpful if you could discuss any potential advantages or disadvantages associated with each type. Thank you in advance for your clarification.