Debugging SDN in HPC Environments
Debugging SDN in HPC Environments
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DOI：
10.1145/3219104.3229277
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发表时间：
2018-07
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影响因子：
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通讯作者：
M. Hayashida;Sergio Rivera;James N. Griffioen;Zongming Fei;Yongwook Song
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作者：
M. Hayashida;Sergio Rivera;James N. Griffioen;Zongming Fei;Yongwook Song
HPC网络和园区网络开始利用各种级别的网络可编程性，范围从可编程网络配置（例如，NETCONF/YANG、SNMP、OF-CONFIG）到基于软件的控制器（例如，OpenFlow Controllers）到通过网络功能虚拟化（NFV）的动态功能放置。虽然可编程网络提供了新的功能，但它们也使网络更难调试。当应用程序经历意外的网络行为时，没有建立的方法来调查可编程网络中的原因，并且许多传统的故障排除调试工具（例如，ping和traceroute）可能完全无用。这种支持可编程性的故障排除工具的缺乏对于试图了解其网络问题的根本原因的研究人员来说是一个严峻的挑战。本文探讨了调试一个利用基于SDN的网络路径的高性能流的所有校园科学DMZ网络的挑战。我们提出了流跟踪器，一个轻量级的，基于数据平面的调试工具，支持SDN的网络，允许最终用户动态地发现网络是如何处理他们的数据包。特别是，我们专注于解决通过使用来自被分析的流的实际数据包来识别SDN路径的问题，而不是现有的昂贵方法，其中将探测数据包注入网络或复制实际数据包以用于跟踪目的。我们的模拟实验表明，流量跟踪器对监控流的性能影响可以忽略不计。此外，我们的工具可以扩展以获得关于实际交换机行为、拓扑和其他流信息的进一步信息，而无需对SDN控制平面的特权访问。
HPC networks and campus networks are beginning to leverage various levels of network programmability ranging from programmable network configuration (e.g., NETCONF/YANG, SNMP, OF-CONFIG) to software-based controllers (e.g., OpenFlow Controllers) to dynamic function placement via network function virtualization (NFV). While programmable networks offer new capabilities, they also make the network more difficult to debug. When applications experience unexpected network behavior, there is no established method to investigate the cause in a programmable network and many of the conventional troubleshooting debugging tools (e.g., ping and traceroute) can turn out to be completely useless. This absence of troubleshooting tools that support programmability is a serious challenge for researchers trying to understand the root cause of their networking problems. This paper explores the challenges of debugging an all-campus science DMZ network that leverages SDN-based network paths for high-performance flows. We propose Flow Tracer, a light-weight, data-plane-based debugging tool for SDN-enabled networks that allows end users to dynamically discover how the network is handling their packets. In particular, we focus on solving the problem of identifying an SDN path by using actual packets from the flow being analyzed as opposed to existing expensive approaches where either probe packets are injected into the network or actual packets are duplicated for tracing purposes. Our simulation experiments show that Flow Tracer has negligible impact on the performance of monitored flows. Moreover, our tool can be extended to obtain further information about the actual switch behavior, topology, and other flow information without privileged access to the SDN control plane.