The distribution of entanglement in quantum networks is typically approached under idealized assumptions such as perfect synchronization and centralized control, while classical communication is often neglected. However, these assumptions prove impractical in large-scale networks. In this paper, we present a pragmatic perspective by exploring two minimal asynchronous protocols: a parallel scheme generating entanglement independently at the link level, and a sequential scheme extending entanglement iteratively from one party to the other. Our analysis incorporates non-uniform repeater spacings and classical communications and accounts for quantum memory decoherence. We evaluate network performance using metrics such as entanglement bit rate, end-to-end fidelity, and secret key rate for entanglement-based quantum key distribution. Our findings suggest the sequential scheme's superiority due to comparable performance with the parallel scheme, coupled with simpler implementation. Additionally, we impose a cutoff strategy to improve performance by discarding attempts with prolonged memory idle time, effectively eliminating low-quality entanglement links. Finally, we apply our methods to the real-world topology of SURFnet and report the performance as a function of memory coherence time.

翻译：量子网络中的纠缠分发通常基于理想化假设进行研究，例如完美同步和集中式控制，而经典通信往往被忽略。然而，这些假设在大规模网络中并不实用。本文从实用角度出发，探讨了两种最小化的异步协议：一种是在链路层面独立生成纠缠的并行方案，另一种是从一方迭代扩展纠缠至另一方的顺序方案。我们的分析考虑了非均匀中继器间距和经典通信，并计入了量子存储器退相干效应。我们使用纠缠比特率、端到端保真度以及基于纠缠的量子密钥分发的密钥生成率等指标来评估网络性能。研究结果表明，顺序方案由于在性能上与并行方案相当且实现更简单，因而更具优势。此外，我们引入了截止策略以提升性能，即丢弃存储器空闲时间过长的尝试，从而有效消除低质量的纠缠链路。最后，我们将所提方法应用于SURFnet的实际拓扑结构，并报告了性能随存储器相干时间变化的结果。