Realizing Flat Multi-Zone Multi-Controller Software-Defined Networks using Zenoh

Software Defined Networks (SDNs) are becoming an increasingly important paradigm in modern networking. By making it possible to detach the control plane from network devices and to instruct those devices via a high-level programming language, SDNs yield a number of administration-level improvements, such as better policy-driven network management and easier support for multi-tenancy. However, moving the complexity of network administration to the controllers entails additional challenges, such as scalability, support for different controller network topologies, and efficient maintenance of network state information. In this paper, we consider a distributed and decentralized approach to the SDN paradigm, targeting zero-configuration scalability and transparency through the Zenoh framework. We explore the application of Zenoh as an east/westbound protocol for SDNs and compare its performance against that of a strongly coupled HTTP-based alternative. Our results show that Zenoh's support for distributed queries enables our SDN architecture to effectively scale to hundreds of SDN controllers with zero configuration overhead, while supporting high east/westbound query throughput.