Breaking Down Network Slicing: Hierarchical Orchestration of End-to-End Networks

Network slicing is one of the key enabling techniques for 5G, allowing network providers to support services with diverging requirements on top of their physical infrastructure. In this article, we address the limited support and oversimplified resource allocation on different network segments of existing end-to-end (E2E) orchestration solutions. We propose a hierarchical orchestration scheme for E2E networks, breaking down the E2E resource management and network slicing problems per network segment. We introduce a higher-level orchestrator, the hyperstrator, to coordinate the distributed orchestrators and deploy network slices (NSs) across multiple network segments. We developed a prototype implementation of the hyperstrator and validated our hierarchical orchestration concept with two proofof- concept experiments, showing the NS deployment and the impact of the resource allocation per network segment on the performance of NSs. The results show that the distributed nature of our orchestration architecture introduces negligible overhead for provisioning NSs in our particular setting, and confirm the need of a hyperstrator for coordinating network segments and ensuring consistent QoS for NSs.