NetSatBench is a distributed emulation platform for evaluating communication protocols and application workloads over large-scale LEO satellite systems. Satellites, gateways, and user terminals are implemented as Linux containers distributed across a cluster of bare-metal or virtual machines, while emulated links are realized through a Layer-2 VXLAN overlay. The system state is maintained in an Etcd key-value store and updated through epoch files, which propagate link and task changes to local control agents running inside the emulated nodes. In contrast to library-oriented tools that require users to write control programs, NetSatBench adopts a higher-level declarative workflow based on JSON "scenario files" and a command-line interface. The platform decouples physical-layer and routing modeling from the emulator core through external plug-ins, while providing built-in support for IPv4 and IPv6 routing, including IS-IS and ideal time-varying routing. Rather than focusing on emulator micro-performance alone, we illustrate what NetSatBench enables through an SRv6-based LEO architecture in which control procedures manage data tunnels between users and gateways under different handover policies. This case study shows how NetSatBench can support protocol-level experimentation under time-varying LEO dynamics and highlights the importance of end-to-end handover strategies that jointly account for the satellites serving both the user and the gateway.

翻译：NetSatBench是一个用于评估大规模低轨卫星系统中通信协议与应用工作负载的分布式仿真平台。卫星、网关和用户终端被实现为运行在裸机或虚拟机集群上的Linux容器，仿真的链路通过二层VXLAN覆盖网络实现。系统状态存储在Etcd键值存储中，并通过节点文件更新，这些文件将链路和任务变更传播到运行在仿真节点内部的本地控制代理。与要求用户编写控制程序的面向库的工具不同，NetSatBench采用基于JSON"场景文件"和命令行界面的更高级声明式工作流。该平台通过外部插件将物理层和路由建模与仿真核心解耦，同时提供对IPv4和IPv6路由的内置支持，包括IS-IS和理想时变路由。我们不只关注仿真器的微性能，而是通过一个基于SRv6的LEO架构来展示NetSatBench的能力，在该架构中，控制过程管理不同切换策略下用户与网关之间的数据隧道。这个案例研究展示了NetSatBench如何支持时变LEO动态下的协议级实验，并强调了端到端切换策略的重要性，该策略需联合考虑同时服务于用户和网关的卫星。