Multipath Inter-Domain Routing Protocols for Quantum Networks With Online Path Selection

Quantum entanglement routing presents a significant challenge in the development of large-scale quantum networks. While intra -domain quantum entanglement routing has been extensively studied, the quantum Internet, like the classical Internet, will likely be serviced by multiple quantum Internet Service Providers (qISPs), necessitating topology-oblivious routing protocols. This paper focuses on the inter -domain scenario, where the network consists of multiple subnetworks owned by mutually untrusted parties without centralized control. In this context, previously proposed entanglement routing strategies, which rely on knowledge of network topology, are no longer applicable. We propose the Quantum Border Gateway Protocol ( QBGP ) for efficiently routing quantum entanglement across qISP boundaries, with built-in multipath load balancing support to enhance network performance. To further ensure high-quality information transmission, we design QPSEL , an online learning algorithm that identifies high-fidelity paths in a topology-oblivious manner. This algorithm utilizes a novel information gain metric, introduced in this paper, to adaptively adjust measurement parameters and minimize resource usage. We implement a quantum network simulator and evaluate both QBGP and QPSEL . Our results show that QBGP effectively distributes entanglements across qISP boundaries and balances traffic through multipath load balancing. Moreover, QPSEL significantly improves network performance by selecting high-fidelity paths with much lower resource consumption compared to existing methods.