Large-scale quantum networks with thousands of nodes require topology-oblivious routing protocols to realize. Most existing quantum network routing protocols only consider the intra-domain scenario, where all nodes belong to a single party with complete topology knowledge. However, like the classical Internet, quantum Internet will likely be provided by multiple quantum Internet Service Providers (qISPs). In this paper, we consider the inter-domain scenario, where the network consists of multiple subnetworks owned by mutually untrusted parties without centralized control. Under this setting, previously proposed quantum entanglement routing policies, which rely on the network topology knowledge, are no longer applicable. We propose a Quantum Border Gateway Protocol (QBGP) for efficiently routing entanglement across qISP boundaries. To guarantee high-quality information transmission, we propose an algorithm named online top-K path selection. This algorithm utilizes the information gain introduced in this paper to adaptively decide on measurement parameters, allowing for the selection of high-fidelity paths and accurate fidelity estimates, while minimizing costs. Additionally, we implement a quantum network simulator and evaluate our protocol and algorithm. Our evaluation shows that QBGP effectively distributes entanglement across different qISPs, and our path selection algorithm increases the network performance by selecting high-fidelity paths with much lower resource consumption than other methods.
Large-scale quantum networks with thousands of nodes require topology-oblivious routing protocols to realize. Most existing quantum network routing protocols only consider the intra-domain scenario, where all nodes belong to a single party with complete topology knowledge. However, like the classical Internet, quantum Internet will likely be provided by multiple quantum Internet Service Providers (qISPs). In this paper, we consider the inter-domain scenario, where the network consists of multiple subnetworks owned by mutually untrusted parties without centralized control. Under this setting, previously proposed quantum entanglement routing policies, which rely on the network topology knowledge, are no longer applicable. We propose a Quantum Border Gateway Protocol (QBGP) for efficiently routing entanglement across qISP boundaries. To guarantee high-quality information transmission, we propose an algorithm named online top-K path selection. This algorithm utilizes the information gain introduced in this paper to adaptively decide on measurement parameters, allowing for the selection of high-fidelity paths and accurate fidelity estimates, while minimizing costs. Additionally, we implement a quantum network simulator and evaluate our protocol and algorithm. Our evaluation shows that QBGP effectively distributes entanglement across different qISPs, and our path selection algorithm increases the network performance by selecting high-fidelity paths with much lower resource consumption than other methods.
The rapid advancement of quantum networking technologies requires a robust and scalable control plane to effectively manage the complexities of quantum communication. This paper presents a novel framework designed to enhance the scalability of the control plane in Quantum Internet architectures. The proposed solution integrates a hierarchical control structure that leverages the Border Gateway protocol (BGP) for adaptive slow high level control plane and a fast low control with virtual circuits in the network in or between AS boundaries (external Quantum BGP), ensuring efficient data quantum transmission while minimizing latency. Additionally, we implement a decentralized approach that enables individual AS to make localized decisions (using quantum control over MPLS, RuleSet, Segment Routing, SDN, etc), thus reducing the burden on central controllers. This work provides a foundational step towards realizing a scalable and efficient Quantum Internet, paving the way for future research and development in quantum communication systems.
Quantum network can provide end-to-end entanglements through quantum operations, supporting various quantum applications such as quantum key distribution and distributed quantum computing. However, many previous proposals for quantum networks assumed the division of quantum network into time slots and batch processing of network communication tasks, performing poorly in dynamic network scenarios and not fully utilizing network resources. This work focuses on the routing problem in entanglement quantum networks, aiming to provide more efficient end-to-end entanglement establishment for upper-layer applications. We propose an on-demand routing algorithm that dynamically adjusts the optimal path based on the current network conditions. Specifically, we consider the benefits of path width for quantum networks and propose an algorithm for finding the shortest wide path. Using this algorithm, each node establishes its own routing table. Additionally, to dynamically avoid network hotspots, we introduce the concept of traffic to reflect the busyness of nodes. Finally, using a dynamic cost calculation method as the routing metric, we select the optimal path for the current request. To evaluate the performance of the proposed quantum routing algorithm, we conducted simulation experiments on SimQN quantum simulation platform. The results show that our approach improves network throughput by 14 percent compared to existing solutions.
The quantum internet will extend today's networks with a capability no classical infrastructure can offer: the distribution of entanglement between distant nodes. That single resource underlies services provably beyond classical reach, such as secure communication against computationally unbounded adversaries, blind delegated computation on remote quantum servers, and entangled networks of atomic clocks. Most of these services require a single multipartite state shared among several nodes at once — for the most part a graph state: one qubit per vertex of a graph, one entangling interaction per edge. This Thesis addresses the distribution of one such state: given an arbitrary network of entanglement switches, deliver the m-qubit path graph state, in the order the application requests, to m single-qubit end nodes — the weakest client model in the literature. Prior protocols support arbitrary topologies or such minimal end nodes, never both. The strongest of them are also centralized: the construction and the memory demand concentrate at a single node. The Thesis takes the opposite approach: a distributed protocol. The Path Graph State Distribution (PathGSD) protocol grows the target state one end node at a time behind a single reference qubit that walks a classically planned route, the shortest ordered Steiner walk. The work is partitioned among the switches, which coordinate only through entanglement and classical messages; no single node ever builds or stores the whole state. The design is deliberately simple, guided by engineering principles, and the simplicity pays at scale: planning is polynomial and completes in seconds on a network of 22,500 switches, where the closest optimization-based alternatives face exponential blow-up. Correctness is proved in the graph-state measurement calculus; a memory-reuse discipline and a parallel multi-domain execution mode complete the protocol. The protocol is implemented as communicating discrete-event processes on the QuantumSavory simulator, validated against exact theoretical expectations, and evaluated against the strongest available baselines: the star-specific Piecemaker and Factory protocols, simulated under noise, and the Graph State Transfer (GST) algorithm's proved cost expressions, evaluated exactly on arbitrary topologies. PathGSD consumes fewer Einstein-Podolsky-Rosen (EPR) pairs than the exact GST baseline on every single-domain family tested, keeps switch memory constant in the network size where the centralized baseline's grows, matches the star-specific protocols on their home topology, and reaches measured speed-ups of up to 1.9× when two administrative domains execute in parallel.
In recent years, quantum communication networks have emerged as a promising alternative to classical communication networks for the transmission of quantum information. One of the challenges for achieving optimal performance in quantum communication networks is the efficient routing of quantum signals across multiple paths. To address this, a variety of routing protocols have been proposed, including multi-path routing protocols. Multi-path routing involves sending a quantum signal through multiple distinct paths simultaneously to reduce delays in the transmission of quantum information. By distributing the quantum information over multiple paths, this approach can provide significant performance improvements, including reduced latency and higher throughput. In addition, multi-path routing can enable new possibilities for the security of quantum communication networks, such as more secure entanglement swapping protocols and improved protection against eavesdropping. In this paper, we investigate the performance of multi-path routing protocols in multi-node quantum communication networks. We consider two approaches to multi-path routing, a basic routing approach based on shortest path optimization, and a more advanced approach based on graph partitions. We evaluate the performance of these protocols in a range of multi-node networks, with focus on the trade-off between latency and throughput. The results show that multi-path routing yields significant performance improvements in such networks and provides an efficient way for routing quantum signals across multiple paths.
A quantum Internet for communicating information encoded in quantum systems over large distances would enable a host of new technologies to be deployed. While exciting progress has been made in small-scale quantum networks, a global quantum Internet will require - like the classical Internet - communicating in a multiple quantum Internet service provider (multi-qISP) setting, with protocols that are oblivious to the global network topology. Here we give a brief overview of quantum networks aimed at those new to the field, present two network-oblivious transport layer protocols for enabling high fidelity communication and performing fault diagnostics, and highlight a number of research opportunities in this nascent field of research.
This paper proposes a dynamic routing protocol for quantum networks based on the fluctuating entanglement states between quantum nodes. The core of the protocol lies in real-time monitoring of entanglement strength and dynamically adjusting routing paths based on these changes. This approach aims to mitigate the risk of information loss due to entanglement decay, ultimately achieving high reliability in quantum routing. Unlike traditional protocols relying on fixed topologies, this protocol adapts to the dynamic nature of entanglement, enhancing routing efficiency and resilience. The protocol utilizes a graph-based representation of the quantum network and employs algorithms for entanglement assessment and path optimization. Mathematical models are presented to formalize the routing process, including the calculation of entanglement fidelity and path cost. The proposed system demonstrates improved routing performance and fault tolerance compared to static routing schemes. The key contribution is a dynamic, adaptive routing strategy that leverages the inherent properties of quantum networks for reliable quantum information transmission.