On Credibility-Based Service Function Chain Deployment

With the advancements of Software Defined Networking and Network Function Virtualization technologies, users can access the software-based service function chain (SFC), which is composed of multiple sequential virtual network function (VNF) nodes. Although SFC is more flexible and adaptive in terms of design and deployment, the security risks should not be underestimated. At present, there is a lack of security or risk assessment for SFC, and SFC deployments rarely take their security into account. However, vulnerabilities and risks can cause VNF node failure during operation, which can lead to issues such as disruptions in SFC service and user data leakage. This paper proposes the concept of SFC credibility, which quantifies the authenticity, availability, and reliability of the VNF nodes from both time and space dimensions. Then, a hierarchical credibility evaluation model is built such that VNF nodes can be selected for the user based on their trustworthiness. A credibility-based deployment strategy is further designed for SFC and the corresponding VNF forwarding graph. Furthermore, a comparative study with three existing deployment strategies has shown the advantages of the proposed method. The extensive experimental results demonstrate the improved trust degree and the acceptance rate of SFC with a limited budget.