Software Defined Networking (SDN) promises to bring unparalleled flexibility, configuration simplification and vendor lock-in removal. On the flip side, the SDN logic centralization requires a global renovation of network equipments. Moreover, it raises issues, e.g., on network resiliency and reaction to failures, that have been naturally and effectively solved in traditional routing protocols.
In this talk, we identify pros and cons of different hybrid SDN models, where SDN and distributed packet forwarding paradigms coexist. The coexistence models span (i) topology-based paradigm separation, (ii) service-based paradigm separation and (iii) paradigm integration. Further, we discuss how we envision that network hybridization can help mitigating major concerns of SDN. On the one hand, it enables retro-compatibility and incremental deployment, hence providing means and incentives to transition to SDN. On the other hand, in our vision, it can represent an interesting network design point that combines the advantages of SDN and traditional paradigms. Unfortunately, due to their intrinsic heterogeneity, hybrid networks present new management and interoperability challenges. We describe techniques to realize network management abstractions, like declarative traffic control and consistent update, that hide the complexity of hybrid networks, and guarantee network-wide correctness.
Stefano Vissicchio received his Master degree in computer science from the Roma Tre University in 2008, and the Ph.D. degree from the same institution in April 2012. He collaborated with the Italian research network ISP (Consortium GARR) between 2011 and 2012. Currently, he holds a postdoctoral position at the University of Louvain (UCL) in Belgium. His research interests are mainly focused on Software Defined Networking, network management and routing.