A R T I C L E I N F O  
A B S T R A C T  

1. Introduction  

2. Preliminaries  

3. Classical Information vs Quantum Information vs Quantum Entanglement  

4. Entanglement: a Deeper Look  

5. Beyond Physical Connectivity  

6. Quantum Internet Protocol Stack: State-of-the-Art  

7. Open Issues and Research Directions  

8. Conclusions  