Towards correct network virtualization
Towards correct network virtualization
复制标题
迈向正确的网络虚拟化
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Brighten Godfrey
中科院分区：
文献类型：
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作者：
S. Ghorbani;Brighten Godfrey
在SDN中，底层基础设施通常被抽象为可以将网络视为逻辑或虚拟实体的应用程序。通常，虚拟抽象与其实际物理实现之间的“映射”不是一对一的，例如，单个“大交换机”抽象对象可以使用一组分布式物理设备来实现。一个关键问题是，哪些抽象可以映射到多个物理元素，同时忠实地保留其本机语义？例如，应用程序开发人员是否总是期望她的抽象“大交换机”能够完全充当物理大交换机，尽管实际上是使用多个物理交换机实现的？我们展示了答案对于现有的虚拟到物理映射技术来说，这个问题是“否”：虚拟“大交换机”和物理网络之间的行为可能不同，从而提供了不正确的应用程序级行为，尽管最普遍和最常用的正确性不变量（例如每个数据包的一致性）始终保留，这些示例表明，为了实现正确性的实际概念，我们需要通过定义端到端正确性来采取第一步。仅关注应用程序的正确性条件，并概述了获得具有正确的虚拟到物理映射的虚拟化系统的研究愿景。
In SDN, the underlying infrastructure is usually abstracted for applications that can treat the network as a logical or virtual entity. Commonly, the ``mappings" between virtual abstractions and their actual physical implementations are not one-to-one, e.g., a single "big switch" abstract object might be implemented using a distributed set of physical devices. A key question is, what abstractions could be mapped to multiple physical elements while faithfully preserving their native semantics? E.g., can an application developer always expect her abstract "big switch" to act exactly as a physical big switch, despite being implemented using multiple physical switches in reality? We show that the answer to that question is "no" for existing virtual-to-physical mapping techniques: behavior can differ between the virtual "big switch" and the physical network, providing incorrect application-level behavior. We also show that that those incorrect behaviors occur despite the fact that the most pervasive and commonly-used correctness invariants, such as per-packet consistency, are preserved throughout. These examples demonstrate that for practical notions of correctness, new systems and a new analytical framework are needed. We take the first steps by defining end-to-end correctness, a correctness condition that focuses on applications only, and outline a research vision to obtain virtualization systems with correct virtual to physical mappings.