In the network function virtualization (NFV) environment, network services are usually provided in the form of service function chains (SFCs), which defines the link order of virtual network functions required in service requests and are mapped to the physical network. Although NFV facilitates the flexible provision of network services, service interruptions may occur as a result of software and hardware failures. Current solutions mostly use the backup method to ensure the reliability of SFCs. However, these methods ignore the SFC construction phase that has an impact on reliability. Besides, the resource efficiency still requires improvement. To address these issues, reliability-oriented SFC construction and backup problems are investigated in this work. First, an instance-sharing and reliable construction algorithm (ISRCA) is proposed to aggregate multiple SFCs into a service function graph (SFG), and perform reliability screening for the SFG set. After mapping the SFG to the physical network, a node-ranking algorithm with centrality and reliability (NRCR) is proposed for backup node selection and backup instance deployment to improve the reliability of SFCs that have not met the requirements. Experimental results demonstrate that under the premise of ensuring reliability, the proposed backup method can reduce the consumption of bandwidth resources by about 11.7%, when combined with the proposed construction method, it can further reduce the backup resources by 13.9%.

中文翻译：

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面向可靠性、资源高效的服务功能链构建与备份


在网络功能虚拟化（NFV）环境中，网络服务通常以服务功能链（SFC）的形式提供，它定义了服务请求中所需的虚拟网络功能的链接顺序并映射到物理网络。虽然NFV有利于灵活提供网络服务，但由于软硬件故障，可能会导致服务中断。目前的解决方案大多采用备份的方式来保证SFC的可靠性。然而这些方法忽略了对可靠性有影响的SFC构建阶段。此外，资源效率仍需提高。为了解决这些问题，本工作研究了面向可靠性的 SFC 构建和备份问题。首先，提出了实例共享和可靠构造算法（ISRCA），将多个SFC聚合成服务功能图（SFG），并对SFG集合进行可靠性筛选。将SFG映射到物理网络后，提出一种具有中心性和可靠性的节点排序算法（NRCR）来进行备份节点选择和备份实例部署，以提高未满足要求的SFC的可靠性。实验结果表明，在保证可靠性的前提下，所提出的备份方法可以减少约11.7%的带宽资源消耗，与所提出的构建方法相结合，可以进一步减少13.9%的备份资源。