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 propose 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：在量子网络中，纠缠分发通常是在理想化假设下进行的，例如完美同步和集中控制，而经典通信往往被忽略。然而，这些假设在大规模网络中不太实际。本文从实用角度出发，探讨了两种最小的异步协议：一种在链路层面独立生成纠缠的并行方案，以及一种从一方到另一方迭代扩展纠缠的串行方案。我们的分析考虑了非均匀的中继间距和经典通信，并计及了量子存储器的消相干效应。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中的密钥速率等指标评估了网络性能。研究结果表明，串行方案因与并行方案性能相当且实现更简单而具有优越性。此外，我们提出了一种截止策略，通过丢弃存储器空闲时间过长的尝试来提高性能，从而有效消除低质量纠缠链路。最后，我们将所提出的方法应用于SURFnet的实际拓扑，并报告了性能随存储器相干时间的变化。