Research On The Routing Algorithm In Quantum Metropolitan Area Network

With the gradual maturity of quantum communication in theory and experiment,the practicalization of quantum communication technology has become a research hotspot.Among them,quantum cryptography communication network is an important direction.At present,dedicated quantum communication networks have been successfully built in actual scenarios.However,as dedicated quantum networks are too expensive to build and require the assistance of classical networks,a solution has been proposed by researchers.It is to build a quantum metropolitan area network(MAN)that is compatible with classical and quantum communications,enabling co-fibre transmission of quantum information,classical information and quantum cryptography information.In this network,classical information can be forwarded through all routers,while quantum cryptography information can only be forwarded through trusted relays,i.e.the quantum MAN should be able to provide different routes for different types of services.In this paper,we focus on the routing algorithm in quantum MANs and then propose a quantum MAN routing algorithm based on Routing Information Protocol(RIP)and a quantum MAN routing algorithm based on joint metrics,which are mainly as follows.Firstly,we propose a quantum MAN routing algorithm based on RIP.This algorithm supports classical communication by preserving the working process of RIP and supports quantum cryptography communication by adding an additional new path to the path from the trusted relay to the quantum network in quantum MANs.In the final routing table,there are two paths from the trusted relay to the quantum network,which are the optimal paths for transmitting classical information and quantum cryptography information respectively.There is only one optimal path from trusted relay to classical network,classical router to quantum network and classical router to classical network.The routing algorithm has the following functions: 1)it can generate classical routes for the whole network and quantum routes for the quantum subnetwork;2)it can select the optimal paths for classical and quantum cryptography information according to the type of information and deliver them to the destination;3)it can provide secure quantum communication while ensuring that classical communication is not affected.The simulation results prove that the routing algorithm can achieve the above functions.Secondly,we propose a quantum MAN routing algorithm based on joint metrics.The above routing algorithm focuses on classical communication and quantum communication in quantum MANs,where the selection of the optimal path for quantum communication depends on path hops which don't reflect the characteristics of quantum networks.To solve this problem,the algorithm considers the influence of quantum keys available on quantum communication and uses the weighted result of the path hops and the minimum keys available to the path as the routing metric to select a path for quantum communication in a quantum MAN.Since the number of keys affects the transmission path of quantum cryptography information in the network,the corresponding processing is done to complete the establishment and update of the route.The simulation verifies that the normal transmission of classical and quantum cryptography information can be ensured in this algorithm,while balancing the link key size and improving the network communication performance and security.