几乎相同：比较物理和虚拟测试床
Virtually the Same: Comparing Physical and Virtual Testbeds
摘要：
网络设计人员、规划人员和安全专业人员越来越多地依赖于大规模虚拟测试平台来模拟网络并做出有关实际部署的决策。然而，关于这些虚拟测试平台与物理测试平台的匹配程度的研究有限。具体来说，这些测试平台所依赖的虚拟化是否能够很好地捕捉真实世界的行为，以支持决策？作为第一步，我们在物理和虚拟测试平台上进行简单的实验，以开始了解测试平台的不同之处和不同之处。我们在一台主机上设置了一个Web服务，并从另一台主机上针对该服务运行ApacheBench，在这些测试期间对每个系统进行检测。我们定义了一个初始的可重复的方法来定量比较测试平台。具体来说，我们比较了三个抽象层次的测试床：应用程序，操作系统（OS）和网络。对于应用程序级别，我们使用ApacheBench结果。对于操作系统的行为，我们比较模式的系统调用排序使用马尔可夫链。这为我们的测试平台中的工作负载和操作系统行为提供了独特的视觉表示。我们还深入研究了读系统调用行为，并展示了在一个级别上两个系统是如何确定和相同的，但随着我们在抽象中的移动，一致性下降。最后，我们使用数据包捕获来比较网络行为和性能。我们重建流和比较每个流和每个实验的统计。我们发现，测试平台中的工作负载的行为是相似的，但支持它的底层流程确实有所不同。根据虚拟网络驱动程序的不同，低级别网络行为在分组化方面可能会有很大变化。虽然这些差异可能很重要，并且了解它们将有助于实验设计人员，但核心应用程序和操作系统行为仍然代表类似的过程。
英文摘要：
Network designers, planners, and security professionals increasingly rely on large-scale virtual testbeds to emulate networks and make decisions about real-world deployments. However, there has been limited research on how well these virtual testbeds match their physical counterparts. Specifically, does the virtualization that these testbeds depend on actually capture real-world behaviors sufficiently well to support decisions? As a first step, we perform simple experiments on both physical and virtual testbeds to begin to understand where and how the testbeds differ. We set up a web service on one host and run ApacheBench against this service from a different host, instrumenting each system during these tests. We define an initial repeatable methodology to quantitatively compare testbeds. Specifically, we compare the testbeds at three levels of abstraction: application, operating system (OS) and network. For the application level, we use the ApacheBench results. For OS behavior, we compare patterns of system call orderings using Markov chains. This provides a unique visual representation of the workload and OS behavior in our testbeds. We also drill down into read-system-call behaviors and show how at one level both systems are deterministic and identical, but as we move up in abstractions that consistency declines. Finally, we use packet captures to compare network behaviors and performance. We reconstruct flows and compare per-flow and per-experiment statistics. We find that the behavior of the workload in the testbeds is similar but that the underlying processes to support it do vary. The low-level network behavior can vary widely in packetization depending on the virtual network driver. While these differences can be important, and knowing about them will help experiment designers, the core application and OS behaviors still represent similar processes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
