A Review of Various Quantum Routing Protocols Designed for Quantum Network Environment

The quantum internet is a global system also called the future internet and is considered a complement to the classical packet switching internet, which performs the function of exchanging messages in the network in an innovative way, as it depends on the basic principles of quantum bits. In order to prepare for the quantum internet, its protocols must be configured initially like routing protocols, and because routing in the quantum internet depends mainly on the property of quantum entanglement, it is facing a constant challenge to what the quantum properties impose, Accordingly, studies in this field continue to emerge, as proposals for protocols are renewed. Therefore, in this research, we present a comprehensive study of the recently proposed quantum routing protocols by classifying these protocols into two categories, the first deals with the routing metrics on which the protocol depends, while the other deals with the problem being solved through the routing protocol. It is shown that although many metrics were suggested for routing protocols, the common metric was the throughput (entanglement rate), In addition, it was considered an essential metric in solving most of the routing problems in quantum networks.