Abstract:

In order to meet the requirements of high reliability and low latency in the 5G network environment， and reduce the resource consumption of network bandwidth at the same time， a Service Function Chain （SFC） deployment method based on node comprehensive importance ranking for traffic and reliability optimization was proposed. Firstly， Virtualized Network Function （VNF） was aggregated based on the rate of traffic change， which reduced the deployed physical nodes and improved link reliability. Secondly， node comprehensive importance was defined by the degree， reliability， comprehensive delay and link hop account of the node in order to sort the physical nodes. Then， the VNFs were mapped to the underlying physical nodes in turn. At the same time， by restricting the number of links， the “ping-pong effect” was reduced and the traffic was optimized. Finally， the virtual link was mapped through k-shortest path algorithm to complete the deployment of the entire SFC. Compared with the original aggregation method， the proposed method has the SFC reliability improved by 2%， the end-to-end delay of SFC reduced by 22%， the bandwidth overhead reduced by 29%， and the average long-term revenue-to-cost ratio increased by 16%. Experimental results show that the proposed method can effectively improve the link reliability， reduce end-to-end delay and bandwidth resource consumption， and play a good optimization effect.

Key words: network function virtualization, Service Function Chain (SFC) deployment, traffic change rate, node comprehensive importance, reliability

摘要：

为满足5G网络环境下高可靠性、低时延的要求，同时降低网络带宽资源消耗，面向流量与可靠性优化提出一种基于节点综合重要度排序的服务功能链（SFC）部署方法。首先，基于流量改变率聚合虚拟网络功能（VNF），从而减少部署的物理节点，提高链路可靠性；其次，通过节点的度、可靠性、综合时延与链路跳数定义节点综合重要度，并依据该重要度对物理节点排序；然后，将VNF依次映射到底层物理节点上，同时通过约束链路条数以减少“乒乓效应”并优化流量；最后，通过k-最短路径算法映射虚拟链路，从而完成整个SFC的部署。相较于原有聚合方法，所提方法的SFC平均可靠性提升2%，SFC端到端平均时延降低22%，平均带宽开销降低29%，长期平均收益开销比提高16%。实验结果表明，所提方法能有效提高链路的可靠性，降低端到端的时延与带宽资源消耗，起到了良好的优化效果。

关键词: 网络功能虚拟化, 服务功能链部署, 流量改变率, 节点综合重要度, 可靠性