  The Quantum Internet is envisioned as the final stage of the quantum
revolution, opening fundamentally new communications and computing
capabilities, including the distributed quantum computing. But the Quantum
Internet is governed by the laws of quantum mechanics. Phenomena with no
counterpart in classical networks, such as no-cloning, quantum measurement,
entanglement and teleporting, impose very challenging constraints for the
network design. Specifically, classical network functionalities, ranging from
error-control mechanisms to overhead-control strategies, are based on the
assumption that classical information can be safely read and copied. But this
assumption does not hold in the Quantum Internet. As a consequence, the design
of the Quantum Internet requires a major network-paradigm shift to harness the
quantum mechanics specificities. The goal of this work is to shed light on the
challenges and the open problems of the Quantum Internet design. To this aim,
we first introduce some basic knowledge of quantum mechanics, needed to
understand the differences between a classical and a quantum network. Then, we
introduce quantum teleportation as the key strategy for transmitting quantum
information without physically transferring the particle that stores the
quantum information or violating the principles of the quantum mechanics.
Finally, the key research challenges to design quantum communication networks
are described.
