The core of the Internet’s timekeeping system are the Stratum-1 timeservers, those connected to reference hardware, that anchor the server hierarchy. It is essential that these root servers are accurate and reliable, and this it is typically taken as a given. We examine this premise through an examination of 102 prominent Stratum-1 servers, using 3 datasets spanning 6 years, collected in reference testbeds with authoritative timestamping. We describe a methodology capable of rigorously removing congestion related variability, allowing server errors to be unambiguously revealed. We use the data and methodology to assess the health of public network timing, and how it varies over time, by reporting on the type, severity, duration, and prevalence of server errors, and how they relate to protocol level information. We present conclusive evidence that the system has problems. We find that errors are widespread, significant, often endemic, consistent over time, and typically come with no warning at the protocol level. Our results highlight the lack of oversight in the current system, and provides the foundation of a server health monitoring capability, necessary to restore and maintain trust in network timing. We describe three specific applications where our results can have an impact. Our data, detailed results and software are publically available.

中文翻译：

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迈向可信赖的时间：远程服务器审核和Internet计时的误区

Internet计时系统的核心是Stratum-1时间服务器，这些服务器连接到参考硬件，用于固定服务器层次结构。这些根服务器必须准确可靠，这通常是给定的。我们通过检查102台著名的Stratum-1服务器，使用跨越6年的3个数据集（在具有权威时间戳的参考测试台上收集）来检查此前提。我们描述了一种能够严格消除与拥塞相关的可变性的方法，可以明确显示服务器错误。我们通过报告服务器错误的类型，严重性，持续时间和普遍性以及它们与协议级别信息的关系，使用数据和方法来评估公共网络计时的运行状况以及其随时间的变化。我们提供的确凿证据表明该系统存在问题。我们发现错误随着时间的流逝是广泛的，重大的，经常是地方性的，一致的，并且通常在协议级别没有警告。我们的结果强调了当前系统缺乏监督，并提供了服务器运行状况监视功能的基础，这是恢复和维持对网络时序的信任所必需的。我们描述了可能对我们的结果产生影响的三个特定应用。我们的数据，详细结果和软件可公开获得。是恢复和保持对网络时序的信任所必需的。我们描述了可能对我们的结果产生影响的三个特定应用。我们的数据，详细结果和软件可公开获得。是恢复和保持对网络时序的信任所必需的。我们描述了可能对我们的结果产生影响的三个特定应用。我们的数据，详细结果和软件可公开获得。