Cost-efficient flow migration for SFC dynamical scheduling in geo-distributed clouds

Abstract

Combining Network Function Virtualization (NFV) and Software Defined Network (SDN) enables the delivery of network services in a flexible and cost-efficient manner. NFV allows elasticity scheduling of Virtual Network Function (VNF) instances to adopt the dynamic variation of network flows, such as VNF instance scale out or in and load balancing. To implement the elasticity scheduling, existing flows need to be re-routed through the VNF instances. One major problem is how to select appropriate flows for migration to reduce migration cost and improve network performance after migration. In this paper, we propose a Cost-efficient Flow Migration framework, CFM, to jointly optimize flow migration cost and network performance after migration (including flow routing cost and maximum VNF instance load) for flow migration in Service Function Chain manner. Experimental results demonstrate that CFM can reduce flow routing cost after migration by 43%∼62% compared with previous works, while achieving similar flow migration cost in scale out/in scenario. In load balancing scenario, CFM can also reduce flow migration cost by 65%∼79% and flow routing cost after migration by 43%∼79% compared with previous works, while ensuring that the maximum VNF instance load does not significantly increase.