Technology trends and challenges in SDN and service assurance for end-to-end network slicing

Network slicing is a core technology to enable new services and solutions in 5G and upcoming 6G communications. However, many issues arise when applying network slicing at a commercial scale, as this requires end-to-end management and automation of the network. Network slicing also requires various state-of-the-art technologies based on collaboration across international standards organizations and open-source communities. This paper reviews and summarizes the recent technological trends and challenges related to Software-Defined Networking (SDN) and service assurance for end-to-end network slicing. First, we focus on the essential use cases and technology trends associated with network slicing, followed by a survey of standard organizations and open-source projects related to network slicing and how they have evolved. Then, we overview an end-to-end network slicing architecture considering Open Radio Access Network (O-RAN) standard. For Radio Access Network (RAN) slicing, we zero in on managing RAN and xHaul with an integrated policy. For transport slicing, we discuss SDN architecture and requirements for network slicing with traffic isolation, unified QoS policy, and traffic engineering. We also cover SLA management using protocol-independent active monitoring and passive monitoring. In the later part of the paper, we summarize technical considerations for end-to-end network slicing, including the RAN-integrated xHaul architecture, converged enterprise network for multi-connectivity, 5G edge data center architectures using programmable data plane, and network slicing security. Overall, this paper reviews the various design issues associated with network slicing and the proposals to resolve these issues to facilitate end-to-end network slicing at a commercial scale.