Q2NS is an open-source quantum network simulator built on ns-3, the de facto standard for classical network simulation. By inheriting ns-3's mature classical stack and event-driven execution model, Q2NS enables faithful co-simulation of quantum-network dynamics and classical signaling, a core requirement for the functioning of any quantum network. Its modular architecture is designed for extensibility, with pluggable quantum-state backends (state-vector, density matrix, stabilizer) and a clean separation between network control and node-level operations. Q2NS comes with a quantum network visualizer Q2NSViz, supporting interactive inspection of both physical- and entanglement-induced connectivity graphs, helping users interpret protocol behavior and entanglement manipulation processes. We present a demonstration of Q2NS, highlighting its ability to capture and simulate the coexistence of quantum and classical communication. The proposed demonstration presents quantum communication scenarios of increasing complexity: from entanglement distribution basics to multipartite graph-state manipulation, complemented by pre-loaded examples in Q2NSViz that require no prior quantum communication or coding experience.

翻译：Q2NS是一个基于ns-3构建的开源量子网络模拟器，ns-3是经典网络模拟的事实标准。通过继承ns-3成熟的经典协议栈和事件驱动执行模型，Q2NS能够实现量子网络动力学与经典信令的忠实协同模拟，这是任何量子网络运行的核心要求。其模块化架构专为可扩展性设计，配备可插拔的量子态后端（态矢量、密度矩阵、稳定子），并在网络控制与节点级操作之间实现了清晰分离。Q2NS附带量子网络可视化工具Q2NSViz，支持对物理连接图和纠缠诱导连接图进行交互式检查，帮助用户理解协议行为与纠缠操控过程。我们展示了Q2NS，突出其捕获和模拟量子与经典通信共存的能力。所提出的演示呈现了复杂度递增的量子通信场景：从纠缠分发基础到多体图态操控，辅以Q2NSViz中预装的示例，这些示例无需任何量子通信或编程经验即可操作。