Re-Architecting NFV Ecosystem with Microservices: State of the Art and Research Challenges

Network Function Virtualization (NFV), considered a key enabler of network "softwarization", promises to reduce capital and operational expenditures for network operators by moving packet processing from purpose-built hardware to software running on commodity servers. However, the state-of-the-art in NFV is merely replacing monolithic hardware with monolithic VNFs, the software that realizes different network functions (e.g., firewalls, WAN optimizers, and so on). Although this is a first step toward deploying NFV, common functionality is repeatedly implemented in monolithic VNFs. Repeated execution of such redundant functionality introduces processing overhead when VNFs are chained to realize Service Function Chains and leads to sub-optimal usage of infrastructure resources. This stresses the need for re-architecting the NFV ecosystem, from VNFs to their orchestration, through modular VNF design and flexible service composition. In that perspective, we make the case for using the microservice software architecture, proven to be effective for building large-scale cloud applications from reusable and independently deployable components, to re-architect the NFV ecosystem. We also discuss the state-of-the-art in realizing modular VNFs from both industry and academia. Finally, we outline a set of research challenges for microservice-based NFV platforms.