Guaranteed-Availability Network Function Virtualization with Network Protection and VNF Replication

Abstract

Network function virtualization (NFV) provides an efficient and flexible way to deploy network services in the form of service function chains (SFCs) by adopting generalized equipment. However, software-based virtualized network functions (VNFs) bring new challenge for network operators in providing service availability guarantees. Traditionally, network-level protection mechanisms are considered separately from function-level VNF backup mechanisms. However, a SFC's availability cannot be guaranteed if only network- level protection mechanisms or only function-level VNF backup mechanisms are considered. In this paper, we propose a coordinated protection mechanism that adopts both backup path protection in the network and VNF replicas at nodes to guarantee a SFC's availability. The proposed mechanism determines the number of replicas required for each VNF in the SFC, and allocates the replicas to physical nodes on the working and backup paths while maintaining ordered dependency among VNFs. Simulation results show that the proposed algorithms contribute to reducing the SFC blocking and the cost of computing resources.