An appealing feature of Network Function Virtualization (NFV) is that in an NFV-based network, a network function (NF) instance may be placed at any node. This, on the one hand, offers great flexibility in redundancy allocation to meet the availability requirements of flows; on the other hand, it makes the challenge unique and difficult. One particular highlight is that there is inherent correlation among nodes due to the structure of the network, implying that special care is needed for redundancy allocation in NFV-based networks. To this aim, a novel approach, called CoShare, is proposed. Originally, its design takes into consideration the effect of network structural dependency. In addition, to efficiently make use of resources, CoShare proposes the idea of shared reservation, where multiple flows may be allowed to share the same reserved backup capacity at an NF instance. Furthermore, CoShare factors in the heterogeneity in nodes, NF instances and availability requirements of flows in the design. The results from a number of experiments conducted using realistic network topologies show that CoShare is able to meet diverse availability requirements in a resource-efficient manner, requiring less resource overbuild than using the idea of dedicated reservation commonly adopted for redundancy allocation in NFV.

中文翻译：

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CoShare：一种高效的 NFV 冗余分配方法

网络功能虚拟化 (NFV) 的一个吸引人的特性是，在基于 NFV 的网络中，网络功能 (NF) 实例可以放置在任何节点上。一方面，这为冗余分配提供了极大的灵活性，以满足流量的可用性要求；另一方面，它使挑战变得独特而困难。一个特别的亮点是，由于网络的结构，节点之间存在固有的相关性，这意味着在基于 NFV 的网络中需要特别注意冗余分配。为此，提出了一种称为 CoShare 的新方法。最初，其设计考虑了网络结构依赖性的影响。此外，为了有效利用资源，CoShare 提出了共享预留的思想，其中可以允许多个流在一个 NF 实例共享相同的预留备份容量。此外，CoShare 将节点的异构性、NF 实例和设计中流的可用性要求考虑在内。使用现实网络拓扑进行的大量实验结果表明，CoShare 能够以资源高效的方式满足不同的可用性要求，与使用通常用于 NFV 冗余分配的专用预留思想相比，需要更少的资源过度构建。